Sunday, October 25, 2009

Corneal thinning disorders

http://www.revophth.com/index.asp?page=1_14448.htm

Thinning in the ‘Quiet’ Eye

  • Dellen. In the absence of inflammation, one of the more likely causes of the thinning is a dell, or an area of non-wetting that thins and then breaks down. The treatment is lubrication, maybe punctal occlusion, and a bandage contact lens, a temporary tarsorraphy.
  • Furrow degeneration. This is a variety of peripheral thinning, typically between the limbus and the arcus senilis, that usually occurs in elderly patients. The hallmark signs of furrow degeneration are that the thinning, if it’s present at all, is very shallow, non-progressive and isn’t visually significant; the eye is white and quiet, there’s no vascularization and there’s no possibility for perforation.No actual treatment is necessary.
  • Pellucid marginal degeneration. This is a cousin to keratoconus, however, where keratoconus tends to mean central or paracentral thinning, pellucid is peripheral. Some patients with pellucid can have severe thinning, usually inferiorly, within a couple of millimeters of the limbus. Though there’s no redness, pain or inflammation, it causes significant irregular astigmatism, so the patient tends to complain of a slow, progressive worsening of vision. On topography, PMD will have an area of inferior steepening that resembles a crab claw. Glasses sometimes help, though the management typically involves a rigid gas permeable contact lens or a hybrid lens like the Synergize. Rarely, you’ll need to do a corneal transplant.
  • Terrien’s marginal degeneration. This presents as a marginal furrow, usually bilateral, and is most common in men between 20 and 40 years of age. It starts as a non-ulcerated area of thinning located superiorly, and it slowly progresses from there. You’ll see vascularization in addition to the thinning, often with a leading edge of lipid. However, the epithelium is also intact with this condition. The thinning can be progressive, and can progress circumferentially or centrally. And, since it starts superiorly, the patient usually gets against-the-rule astigmatism. You can manage the astigmatism with glasses or, failing that, RGPs or hybrid lenses.

Thinning in the ‘Hot’ Eye

  • Patients can also present with peripheral thinning accompanied by ulceration and general inflammation. These are the presentations are more concerning since actual tissue is being lost. Since several of the ulcerative conditions have similar appearances, it takes more diagnostic detective work to narrow down the cause in these cases.
  • If the eye is red and painful, and there’s peripheral thinning with an epithelial defect, then you first assess the defect’s size, location and whether it’s associated with a hypopyon.
  • None of the immune conditions cause a hypopyon, while the bacterial ones do. If there’s a hypopyon, corneal specialists say to proceed as if it’s a bacterial infection until proven otherwise. Scrape it, culture it and put the patient on antibiotics.
  • When presented with a non-infectious peripheral ulcerative keratitis, however, first suspect rheumatoid arthritis or another autoimmune condition. If a patient doesn’t already have a diagnosis of rheumatoid, physicians also suspect Wegener’s granulomatosus, a serious vasculitis; or Mooren’s ulcer, which is peripheral ulcerative keratitis of unknown etiology. Unfortunately, all three ulcerative conditions have similar characteristics, and serologic testing is often the key to making the diagnosis. Corneal specialists say many patients who present with PUK often have already been diagnosed with rheumatoid disease and are on some type of systemic medication for it already, which aids the diagnosis.
  • If the patient doesn’t already have a diagnosis of a systemic disease associated with peripheral corneal thinning with ulceration, order a panel of blood work: check for rheumatoid factor, erythrocyte sedimentation rate, an antinuclear antibody test, an anti-neutrophil cytoplasmic antibody test, a complete blood count, check for hepatitis-C, (because there’s one form of peripheral thinning that looks like peripheral ulcerative keratitis or Mooren’s ulcer but which is actually associated with hepatitis-C and is very responsive to interferon therapy).
  • If autoimmune disease isn’t the cause, the other two frequent diagnoses, Wegener’s granulomatosus and Mooren’s ulcer
  • Wegener’s is one of the main differentials in PUK because, if it’s missed, it can kill someone. Wegener’s is a vasculitis that manifests with peripheral corneal ulcers that mimic a Mooren’s ulcer, in which there’s a nasal or temporal immune-looking ulcer—in other words, there’s no hypopyon in the anterior chamber. The patient needs a chest X-Ray or a CAT scan of the chest because the Wegener’s patient will have a classic diagnostic picture in that region. If a mass is observed, a biopsy is necessary in some cases. With Wegener’s in mind, an ANCA is needed in all cases of PUK. If a patient’s ulceration involves the sclera as well as the cornea, suspect Wegener’s.
  • If the PUK isn’t from an autoimmune condition like RA, Wegener’s or hepatitis, it’s classified as Mooren’s ulcer, or a peripheral ulcerative keratitis of unknown etiology.
  • Mooren’s is typically more chronic, progressive and very painful. It will begin in the periphery and spread both circumferentially and centripetally. The key sign is that there will be a leading, undermined edge of de-epithelialized tissue. There will also usually be blood vessels crossing the edge. There’s also a milder form of Mooren’s ulcer that’s more limited and actually responds well to medical therapy consisting of lubrication and low-dose steroids and tarsorraphy, if necessary.
  • There are also less common causes that need to be kept in mind, as well: Corneal melting can occur in the setting of the neurotrophic cornea or from the frequent use of topical anesthetics or topical non-steroidal anti-inflammatories like Acular, Xibrom and Nevanac. Another cause, which was more common when we did more scleral surgery, is surgically induced necrotizing scleritis, in which there’s melting of the sclera from an old cataract wound. This was rare to begin with, and it still is, but it’s worth being aware of.
  • The cause may also be just staph marginal hypersensitivity, a relatively mild condition. In blepharitis and other lid disease, patients can get small white infiltrates at the limbus. Those infiltrates can be associated with some thinning and, when they heal, they can result in some scarring and thinning, but they’re not that serious.

Vitreous hemorrhage differentials

  • blunt trauma
  • penetrating trauma
  • abusive head trauma
  • neoplasm
  • venous malformations
  • Terson’s syndrome http://emedicine.medscape.com/article/1227921-overview
  • inflammation such as pars planitis
  • regressed retinopathy of prematurity
  • X-linked retinoschisis
  • familial exudative vitreoretinopathy

Keratoconus


http://www.revophth.com/index.asp?page=1_14488.htm



  • Down’s syndrome, Ehler’s-Danlos syndrome, Leber’s Congenital Amaurosis and atopy associated with KC but are likely secondary to the eye rubbing associated with these conditions instead of genetic link

  • i..e. secondary association in response to environmental or behavioral factors

  • only 7 percent of patients report awareness of other family members with this condition

  • KC is a complex genetic disease that requires interaction with environmental factors to make a genetically determined predisposition clinically apparent

  • hypothesis that KC includes a genetically altered dose-response curve to eye rubbing

  • Eye rubbing performed by the purely allergic patients is fairly straightforward. It is in response to allergic symptoms which patients consistently report as “itching.” When asked about eye rubbing, allergic patients are highly aware of their behavior and a typical response might be, “when my eyes itch, I rub them and if they didn’t itch, I wouldn’t rub them.”

  • KC patients are very different in this regard. While they may have allergies and their symptoms can certainly overlap with allergic complaints, their observations often include comments not typically associated with allergies. The motivation behind their eye rubbing may include itching as a complaint, but unlike the allergic patient, they often report a number of other reasons such as, “burning” or “it just feels good” or commonly, “I need relief.” KC patients also describe motivating factors for eye rubbing that are never offered by the purely allergic patient, such as, “It helps me see better.” (temporary alteration in surface topography or more likely, an improvement in the quantity, quality and distribution of surface lubrication?)

  • Allergy vs KC patients: different perceived need to rub, timing, contact method, pressure applied, duration, motion, location over the lid and the derived benefit

  • the purely allergic patient, in response to allergic itching, generally begins by using a flat instrument (back of hand, front of hand or palm applied broadly, rubbing back and forth, horizontally over the eyelids generating eyelid movement and pressure and “traction” within the lid itself with only modest pressure transmitted to the cornea. This is often followed by a transition to using the tip of the index finger as allergic rubbing tends to migrate nasally, concentrating point pressure over the caruncle for the follow through and completion of the effort. Added contact pressure is then applied at this stage when the caruncle is being rubbed and a circular component may also be added to the motion after this transition to the caruncle

  • The KC patient, on the other hand, has a limited number of favorite techniques, the majority of which begin with a pointed instrument, either a knuckle (middle knuckle more commonly than distal or proximal knuckle or fingertip(s)

  • The hallmark of the KC rub is the circular motion of this point-like pressure confined over the cornea, often with pronounced pressure transmitted posteriorly—much more than with the allergic rub (apart from the allergic caruncle rub). The intensity and duration (10 to 180 seconds, up to 300 seconds) are much greater in KC patients, as is the repetitive nature. The perceived benefit and relief reported by the KC patient is different from the relief from itching sought and achieved by the allergic patient. Interviewing these patients “in action,” the KC patient is more likely to elucidate an experience of ecstasy and euphoric rapture during and toward the completion of the rub, wanting to do even more.

  • The purely allergic patient describes the process as filling a need, wishing he did not have to do this, and in the end reports more of a “mission accomplished.”

  • Allergic patients are highly aware of these episodes and tend to be fairly accurate when reporting their symptoms, as well as the frequency and severity of eye rubbing, in response to these allergic challenges.

  • KC patients often under-report eye rubbing when first asked about it, perhaps reflecting a desensitized awareness as this repetitive behavior or habit becomes increasingly incorporated into their daily routine.

  • KC patients may also exhibit repetitive and even ritualistic behavioral tendencies compounding the physical need they feel to rub their eye. This can include profound eye rubbing at certain times of the day or associated with specific activities such as immediately after awakening or after removal of their contact lenses.

  • It appears directed at a stimulus derived from the cornea or from the interaction between the eyelid and corneal surface in the absence of a contact lens. While eye rubbing facilitates lubrication and the interaction between the eyelid and the corneal surface in the absence of a contact lens, I also wonder if contact lens removal improves oxygenation to corneal nerves that are stretched and stressed from KC but also somewhat hypoxic after contact lens wear.

  • This improvement in oxygenation immediately after contact lens removal might initiate a pain signal that responds favorably to eye rubbing—perhaps in the same way that the gate-control theory of pain explains the benefits of acupuncture or therapeutic massage.

  • Relative hypoxia from eyelid closure and the need for better surface lubrication are both factors that might also explain why some patients report early morning as another favorite time to rub their eyes.

  • Eye rubbing may also be incorporated in behavioral tendencies associated with obsessive compulsive disease (OCD) as some of these patients reveal these tendencies in other activities in their life.

  • It is not uncommon for KC patients to report their eye rubbing more accurately when they return for a follow-up visit, noting that it was called to their attention either by the eye doctor raising the question during the first visit or by family, friends or co-workers the patients might survey with regard to their behavior. Another reason for under-reporting this behavior is an embarrassment that some of these patients feel; they may have been chastised growing up or told over the years to stop rubbing their eyes by their peers or by those in authority. For these patients, it is like nail biting, and when asked to demonstrate their eye rubbing technique, they will often blush and remark on the embarrassment this brings.

  • If the patient and their family denies history of rubbing, another theory is that there may be a tendency toward putting pressure on or around the more severely affected eye while they sleep at night.

  • position was exclusively on the affected side and involved a hand position that placed considerable pressure on the eye itself.

  • consistent tendency for patients to sleep on the side that is more severely affected or progressing more rapidly.

  • Some of these patients like to sleep with their hand or fist directly against their eyelid and are more likely to hug their pillow in a manner that generates some compression around their eyes

  • While some generate substantial pressure—in effect, grinding their eye into the pillow—even the milder forms of pressure can deliver considerable cumulative effect over time.

  • Adding further to this is the thermal impact of compressing a pillow against the closed eyelid, reducing the normal dissipation of heat.

  • These patients with asymmetric KC are also more likely to develop floppy eyelids to a greater degree on their sleeping side.

  • Also patients are more likely to have undiagnosed obstructive sleep apnea (OSA), a condition that may lead to a host of cardiac and pulmonary problems, hypertension, esophageal reflux, weight gain and shortened lifespan.

  • Some KC patients develop OSA symptoms prior to acquiring their weight gain, further supporting the need for a heightened sense of awareness among clinicians who may otherwise overlook this condition.

  • Referring these patients to a sleep lab for formal study if they report restless sleep, snoring, periodic apnea, daytime restlessness, unexplained hypertension or any of the other symptoms commonly associated with OSA.

  • For those patients already diagnosed with OSA, one should be aware that their favorite sleeping position may be altered by their need to wear a CPAP or BiPAP mask, some of which require patients to sleep on their back to maintain an adequate seal.

  • link between KC and obesity. These heavier patients were also more likely to demonstrate a floppy eyelid.

  • a hypothesis that a subset of KC patients represents a syndrome that includes a floppy eyelid, “floppy” keratoconic cornea, and floppy soft palate leading to OSA is intriguing and worth pursuing as we try to better understand aging and mortality among our KC patients

  • this still does not fully account for the observed reduction in disease prevalence with advancing age.

  • patients usually point to the moreadvanced eye as their favorite eye to rub prior to PK. After PK; however, patients often switch so that the other eye becomes the favorite eye to rub

  • Their need for relief diminishes, further supporting that it is not the conjunctiva or eyelids producing this need to eye rub, in contrast to what we see with allergic patients. Instead, this may be a product of neurotrophism making the dry-eye symptoms of lid wiper epitheliopathy less symptomatic. Alternatively, this may provide added support to the gate-control theory of pain with neurogenic factors originating in the cornea “short-circuited” by vigorous eye rubbing and then dramatically reduced when tissue containing these stretched or altered nerves is eventually removed with PK.

  • Do the prominent corneal nerves seen by slit-lamp biomicroscopy anatomically represent either a response or a contribution to the viscious eye rubbing cycle we see clinically?

  • The case is strong that eye-rubbing tendencies of KC patients are overall quite distinct from those seen in the purely allergic patient. Interestingly, these same tendencies are seen in a number of patients with post-LASIK keratoectasia.

  • Perhaps the best model for KC is a genetic condition that is particularly susceptible and even accelerated by trauma resulting from eye rubbing or mechanical weakening from LASIK surgery?

  • The observed association with OSA brings to mind a number of plausible hypotheses, the most intriguing of which would be a syndrome that includes KC, floppy eyelid and OSA.

  • Consider the genetically susceptible host with the environmental “second hit” provided as follows: a) eye rubbing or nocturnal eye pressure leading to the “floppy” keratoconic cornea; b) sleeping position and eye rubbing leading to the floppy upper eyelid; and c) the genetically affected soft palate that has a greater propensity for developing OSA due to a greater susceptibility to become “floppy” and obstruct from airway turbulence at lower levels of weight gain.

Thursday, October 22, 2009

Retinitis pigmentosa

http://www.noah-health.org/en/eye/disorders/retinitispigment.html

r/o Usher Syndrome and Bardet-Biedl Syndrome

Usher: http://www.ushersyndrome.nih.gov/whatis/fulltext.html

Bardet-Biedl Syndrome http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=gene&part=bbs

Ophthalmology minutes

http://telemedicine.orbis.org/bins/content_page.asp?cid=1-600

Strabismus Diagnosis - Comprehensive Evaluation

http://telemedicine.orbis.org/bins/volume_page.asp?cid=1-3-4-7

Nystagmus

http://telemedicine.orbis.org/bins/volume_page.asp?cid=1-3-4-34

Acquired strabismus

Differential diagnoses:

* Thyroid ophthalmopathy
* Myasthenia
* Diabetic vasculopathy - stroke
* Aneurysm
* Tumor
* Multiple sclerosis (nystagmus - oscillopsia, internuclear ophthalmoplegia)
* Blowout fracture
* Decompensated congenital IV N palsy (head tilt - facial asymmetry)
* Convergence insufficiency
* Post retina or glaucoma surgery
* Myositis
* Etc.

http://telemedicine.orbis.org/bins/volume_page.asp?cid=1-3-4-25

Brown's syndrome

  • "superior oblique tendon sheath syndrome".
  • The definition of the syndrome has since been expanded to limited elevation in adduction from mechanical causes around the superior oblique
  • also been called pseudo paresis of the inferior oblique
  • Left Brown - Limited Elevation in Adduction
  • Favored head posture with left Brown: head up and to right where eyes do not go! Eyes positioned down and left to look straight ahead.
  • 1. Vision and stereo acuity usually normal
    2. Chin up face points to opposite side
    3. Deficient elevation in adduction
    4. Usually some elevation limitation in straight upgaze and in abduction
    5. Widened palpebral fissure on adduction
    6. May or may not have downshoot of involved eye in adduction
    7. May be acquired
    8. May be intermittent with or without pain

Causes:

  • "Short" Superior Oblique Tendon -Including Anomalous, Broad Insertion
  • Fascial Restrictions
  • Intrasheath Septae
  • Trochlear Entrance Restriction
  • Inflammation of the Trochlea
  • Cyst of the Reflected Tendon
  • Trochlear Trauma* (Canine Tooth) * This causes superior oblique underaction and Brown syndrome
  • Tuck of the superior oblique tendon is usually done at or near the insertion on globe

http://telemedicine.orbis.org/bins/volume_page.asp?cid=1-3-4-18

White/yellow flat macular lesion/pigment change DD

  • Posttraumatic - pigmentary disturbance; cysts or hole at macula
  • Postinflammatory - chorioretinal atrophy with pigment clumping at center and periphery of lesion
  • Coloboma of macula-atrophic area at macula often associated with coloboma of disc; sclera may be ectatic (see p. 450)
  • Radiation injuries-common after solar eclipse; punched-out appearance
  • Fuchs dark spot-pigmented spot associated with other signs of degenerative myopia
  • Drugs, including the following:
    adrenal cortex injection, aldosteroneallopurinol (?), amodiaquine, betamethasone (?), chloroquinecortisone (?), desoxycorticosterone (?), dexamethasone (?), diiodohydroxyquin, fludrocortisonefluprednisolone (?), griseofulvinhydrocortisone (?), hydroxychloroquine, indomethacin (?), iodochlorhydroxyquin, methylprednisolone, oral contraceptives, paramethasone (?), prednisolone (?), prednisone (?), quininetriamcinolone
  • Stellate retinopathy - star-shaped exudates
  • Hard exudates and circinate retinopathy
  • Drusen – common, discrete yellow spots beneath the retina
  • Doyne honeycomb choroiditis-rare; honeycomb pattern of yellow patches at posterior pole; degenerative changes at macula
  • Heredomacular dystrophies:
  • Best disease (vitelliruptive macular dystrophy) up to 18 years of age; egg-yolk lesion at macula, later absorbed to leave atrophic scar
  • Fundus flavimaculatus - yellow patches at posterior pole; degenerative changes at macula
  • Stargardt disease (juvenile macular degeneration) to 10 years of age; variable appearance in different families; bilateral lesions showing some degree of symmetry
  • Behr disease (optic atrophy-ataxia syndrome) – adults, similar to Stargardt type
  • Presenile and senile-pigmentary changes followed by atrophy, bilateral and symmetric
  • Central choroidal sclerosis - rare, atrophic retina with sclerosed choroidal vessels showing clearly
  • Central areolar choroidal atrophy-rare, exudate and edema followed by sharply defined atrophic area with white strands of choroidal vessels
  • Pseudoinflammatory macular dystrophy-rare, initially edema and exudates followed by scarring with pigmentary disturbance and atrophic patches
  • Gaucher disease (glucocerebroside storage disease)-rare, ring-shaped macular lesions, lipid deposits in cornea and conjunctiva
  • Diffuse leukoencephalopathy - rare, white deposits in periphery and macular area
  • Sjögren-Larsson syndrome (oligophrenia-ichthyosis-spastic diplegia syndrome)
  • Angioid streaks
  • Multiple evanescent white-dot syndrome (MEWDS) usually unilateral, predominantly healthy women, vitreitis
  • Acute multifocal placoid pigment epitheliopathy – rare, map-like pigmentary disturbance of posterior pole or more widespread over posterior fundus

White Dot Syndromes

http://emedicine.medscape.com/article/1227778-overview

  • group of idiopathic multifocal inflammatory conditions involving the retina and the choroid
  • characterized by the appearance of white dots in the fundus

Include:
  • acute posterior multifocal placoid pigment epitheliopathy (APMPPE),
  • serpiginous choroiditis,
  • multiple evanescent white dot syndrome (MEWDS),
  • multifocal choroiditis and panuveitis (MCP),
  • punctate inner choroidopathy (PIC),
  • diffuse subretinal fibrosis (DSF)
  • presumed ocular histoplasmosis syndrome (POHS)
  • birdshot retinochoroidopathy

Acute Posterior Multifocal Placoid Pigment Epitheliopathy (APMPPE)

  • occurs predominantly in young adults, with a mean age of onset of 27 years
  • presents with bilateral, acute, painless loss of vision
  • in approximately one third of patients, symptoms of fever, myalgia, headache, and malaise are noted prior to the onset of ocular symptoms.
  • vitreous cells and flat yellow-white placoid lesions in the posterior pole, ranging in size from 0.5 to several disc diameters. These lesions spontaneously become less opaque within 2-3 weeks and develop pigment changes at the level of the retinal pigment epithelium. During this time, a rapid improvement in the visual acuity may occur
  • most patients completely recover; however, in a small percentage of patients, atrophy and scarring of the retinal pigment epithelium develop with resultant poor visual acuity.
  • additional findings may include optic disc edema and episcleritis.
  • APMPPE has been associated with erythema nodosum, a vasculitic condition that consists of painful subcutaneous nodules in the axilla and lower extremities.
  • APMPPE with concomitant cerebral vasculitis also has been described.
  • Fluorescein angiography displays early hypofluorescence and late hyperfluorescence of the active lesions. Inactive lesions may show window defects as a result of depigmentation of retinal pigment epithelium. Indocyanine green angiography (ICG), with its ability to visualize the choroidal vascular structure, also has been used to diagnosis APMPPE. ICG angiography displays decreased visibility of the larger choroidal vessels in the early phase.
  • The differential diagnosis includes sarcoidosis, MEWDS, and birdshot retinochoroidopathy. Sarcoidosis has small yellow-white retinal pigment epithelial lesions that are usually in the peripheral fundus. Ocular sarcoidosis may present together with systemic findings of the disease, which include bilateral pulmonary hilar adenopathy, articular changes, and erythema nodosum. Patients with MEWDS have unilateral visual loss and have small lesions that usually are located in the midperiphery. MEWDS displays early hyperfluorescence on fluorescein angiography and less depigmentation overall. Birdshot retinochoroidopathy, which often has an association with the presence of the human leukocyte antigen A29 (HLA-A29), also is usually bilateral but presents subacutely with smaller lesions and is associated with significant vitreous reaction and retinal vasculitis. Fluorescein angiography may show retinal vascular leakage and macular edema.
  • The pathogenesis of APMPPE is unknown. Occasionally, a viral prodrome occurs, and speculation exists that APMPPE may have an infectious etiology. In fact, adenovirus 5 has been isolated in one patient with a concurrent viral infection. APMPPE also has been associated with human leukocyte antigen DR2 (HLA-DR2) and human leukocyte antigen B7 (HLA-B7), suggesting a genetic predisposition to the disease.
  • No treatment is required for most patients with APMPPE. The disease is self-limited with spontaneous recovery of vision in most cases. Of those eyes that are affected, 90% of them typically achieve a visual acuity of more than 20/25. In rare cases, recurrences may occur within 6 months of the initial episode, thereby giving a less favorable prognosis.
  • In cases of foveal involvement, corticosteroids may be considered, although their efficacy has not been proven in a controlled study. Corticosteroids may be beneficial in cases of associated cerebral vasculitis. Choroidal neovascularization is a rare complication of APMPPE.

Serpiginous Choroiditis

  • also known as geographic choroidopathy
  • rare condition that typically affects middle-aged males
  • patients present with unilateral or bilateral visual loss when the macula is involved, and they also may notice photopsias and scotomata
  • Gray-white lesions are noted at the level of the retinal pigment epithelium.
  • Active lesions usually are found at the border of inactive lesions and appear in an interlocking polygonal pattern that spreads out toward the periphery from the optic nerve.
  • Macular involvement is common.
  • Mild vitreous and anterior chamber inflammation is observed in one third of cases.
  • Branch vein occlusions, although not common, have been reported.\
  • On fluorescein angiography, hypofluorescence is present in the center of the lesions, and hyperfluorescence is present at the rim of the lesions in the early phase. Active lesions are hyperfluorescent in the late phase. Inactive lesions are hypofluorescent in the early phase and staining of the sclera is visible in the late phase. In addition, the choroidal vessels are easily seen on fluorescein angiography. ICG angiography does not contribute significantly toward the diagnosis.
  • Serpiginous choroiditis often is confused with APMPPE. Younger patients with APMPPE who may have a viral prodrome typically present with an acute loss of vision. The lesions in APMPPE do not emanate from around the optic nerve, and active lesions do not border inactive lesions. APMPPE causes less scarring than serpiginous choroiditis. APMPPE has an acute onset and typically has a rapid recovery, whereas serpiginous choroiditis has a subacute presentation and ultimately results in significant visual loss, especially if the macula is involved. In addition, patients with serpiginous choroiditis are more likely to develop choroidal neovascularization than patients with APMPPE. Other diseases to consider in the differential diagnosis include MCP, age-related macular degeneration, and sarcoidosis.
  • The etiology of serpiginous choroiditis is unknown. Speculation exists regarding an association with exposure to various toxic compounds.
  • The pathology of serpiginous choroiditis reveals lymphocytic infiltration in the affected choroid and the presence of fibroglial tissue surrounding the Bruch membrane.
  • Within a few weeks, the active lesions convert into inactive lesions with eventual retinal pigment epithelial atrophy.
  • If foveal involvement is absent, the visual prognosis is good, and no treatment is necessary. However, if the fovea is involved, treatment with anti-inflammatory medication is recommended.
  • A study involving long-term treatment with prednisone, cyclosporine, and azathioprine demonstrated a possible benefit. Additionally, the role of cyclosporine alone has been investigated.
  • Recurrences are common in serpiginous choroiditis.
  • A serious complication of serpiginous choroiditis is choroidal neovascularization.
  • Laser photocoagulation has been used for extrafoveal choroidal neovascularization; however, it is of limited benefit, likely due to the abnormalities of the Bruch membrane and the presence of lymphocytic infiltration.

Multiple Evanescent White Dot Syndrome

  • MEWDS occurs predominantly in young to middle-aged females, with a mean age of onset of 26.8 years.
  • In one half of patients, an associated viral prodrome is present.
  • Patients also present with acute, painless, unilateral loss of vision.
  • patients may notice photopsias and scotomata, particularly in the temporal visual field.
  • Examination of the fundus reveals flat, multifocal, gray-white lesions that appear to extend as deep as the retinal pigment epithelium layer. The lesions typically are found outside the macula in the posterior pole, ranging in size from 100-300 µm in diameter. The lesions can be subtle in appearance, and careful examination is essential for accurate diagnosis.
  • A characteristic finding of MEWDS is foveal granularity.
  • Additional findings that may be present include optic disc edema, mild vitritis (usually posterior vitreous cells), and a relative afferent pupillary defect.
  • A report described the appearance of brown areas after the resolution of the acute phase of
  • Fluorescein angiography demonstrates early punctate hyperfluorescence with late staining, in areas corresponding to the white dots. On closer examination, the early fluorescence of the lesions appears in a wreathlike pattern. Patients with MEWDS may have optic nerve staining and retinal vascular sheathing. ICG angiography demonstrates multiple hypofluorescent spots in the posterior pole and hypofluorescence around the optic nerve head, particularly in patients with enlarged blind spots. The hypofluorescent spots persist until the patient recovers.
  • Visual field testing usually shows considerable enlargement of the blind spot. The actual defect does not correlate with the distribution of white dots in the fundus, since the presence of white dots around the nerve are rare and the visual field defect persists even after the disappearance of the lesions.
  • Electroretinographic studies demonstrate reduction of the a-wave amplitude and early receptor potential with prolonged early receptor potential regeneration times, indicating photoreceptor dysfunction. These abnormalities resolve with resolution of the disease.
    Differential diagnosis
  • The differential diagnosis includes APMPPE, birdshot retinochoroidopathy, acute retinal pigment epitheliitis, and diffuse unilateral subacute neuroretinitis. APMPPE causes bilateral visual loss. The lesions in APMPPE are larger than MEWDS, and they block fluorescence early on fluorescein angiography, whereas there is early hyperfluorescence in MEWDS.
  • Birdshot retinochoroidopathy differs from MEWDS because it presents as bilateral disease in older patients. Accompanied by a subacute presentation, it is associated with significantly greater vitreous inflammation when compared to MEWDS.
    Acute retinal pigment epitheliitis, one of the very rare white dot syndromes, also presents with acute visual loss in young patients. However, it differs from MEWDS because the lesions are located in the macula and are dark in color with a halo of depigmentation.
  • Electroretinogram findings are normal in these patients.
  • Diffuse unilateral subacute neuroretinitis has been attributed to an intraocular nematode. Patients present with unilateral loss of vision and widespread retinal pigment epithelial atrophy and optic atrophy. It differs from MEWDS in that there is a prolonged clinical course and associated progressive loss of vision.
  • The pathogenesis of MEWDS is unknown. The frequent viral prodrome may indicate an infectious etiology. Since the disease has a strong female predominance, hormonal status as a possible contributing factor is being investigated.
  • MEWDS is a self-limited disease with almost all patients regaining good visual acuity within 3-9 weeks. Consequently, no treatment is recommended for patients with MEWDS. The lesions disappear without scarring, and photopsias and scotomata gradually resolve.
  • Occasionally, patients with MEWDS may have persistent blind spot enlargement.
  • Although uncommon, recurrences can occur. However, the prognosis is fairly good for these patients.
  • A rare complication of MEWDS is choroidal neovascularization that may require laser photocoagulation.

Multifocal Choroiditis and Panuveitis

  • characterized by multifocal chorioretinal lesions with significant anterior chamber and vitreous inflammation.
  • It occurs predominantly in myopic females between the second and sixth decades of life, with a mean age of onset of 33 years.
  • Patients usually present with an acute onset of blurred vision, photopsias, and scotomata.
  • Bilateral involvement is present in approximately 75% of patients.
  • Examination of the fundus reveals multiple yellow or gray lesions at the level of the choroid and retinal pigment epithelium.
  • These active lesions can range in size from 50-1000 µm and can be numerous (as many as several hundred at a time).
  • The lesions usually are concentrated in the midperiphery.
  • The active lesions can progress into chronic lesions, which are punched-out atrophic scars that develop pigmentation over time.
  • The optic disc is usually normal, although, in some cases, it may be edematous.
  • Peripapillary scarring and prominent linear chorioretinal streaks also may be present.
  • Choroidal neovascularization can be present, in addition to peripapillary fibrosis.
  • Almost all patients have vitreous inflammation, and many have anterior chamber inflammation.
  • The patient also may present with cystoid macular edema.
  • The diagnosis is based on clinical examination and can be confirmed by angiographic studies. Fluorescein angiography demonstrates that active lesions show early hypofluorescence and late hyperfluorescence. However, if patients present at a later stage, the active lesions usually have scarred or are in the process of scarring, thereby giving early hyperfluorescence and late staining. If choroidal neovascularization is present, it usually is observed as early hyperfluorescence with a lacy appearance and a late leakage of dye. ICG angiography shows both active and chronic lesions as hypofluorescent. ICG angiography of choroidal neovascularization reveals hyperfluorescence.
  • The major disease to consider in the differential diagnosis is POHS. POHS has similar ocular findings, including multiple atrophic chorioretinal spots, choroidal neovascularization, and peripapillary scarring. The lesions in POHS are less numerous and smaller. However, the key distinguishing feature is that POHS does not present with anterior segment and vitreous inflammation. Other diseases to consider in the differential diagnosis of MCP include sarcoidosis and birdshot retinochoroidopathy.
  • The pathogenesis of MCP is unknown. Controversy exists regarding the significance of a statistical association of the disease with the Epstein-Barr virus.
  • Patients with MCP have a chronic condition with recurrent bouts of active lesions and vitreous inflammation. These patients require long-term follow-up care.
  • Overall, visual prognosis is variable, with final visual acuity of 20/40 or better in 66% of eyes. With each bout of inflammation, patients with MCP develop more active lesions, which later become atrophic with significant scarring.
  • Visual loss usually results from inflammatory scars in the fovea, cystoid macular edema, choroidal neovascularization, and iatrogenic induced by long-term corticosteroid use.
  • The treatment of patients with MCP consists of corticosteroids. Oral steroids are helpful in patients with active posterior segment inflammation or with cystoid macular edema.
  • Topical corticosteroids are helpful if there is severe anterior segment inflammation.
  • However, cases in which corticosteroids have not improved the inflammation have been described.
  • The most common complication of MCP is choroidal neovascularization, which develops in 30% of patients. Laser photocoagulation may be indicated in these patients. Oral steroids also may be used for choroidal neovascularization since they have been shown to decrease the neurosensory detachments associated with choroidal neovascular membranes.
  • Two conditions are related to MCP. The first condition, PIC, affects young myopic females. It presents with an acute bilateral loss of vision, photopsias, and scotomata. However, PIC lesions are smaller and have a more cylindrical punched-out appearance. Unlike MCP, patients with PIC do not have anterior segment or vitreous inflammation. Also, patients with PIC rarely have recurrences of the lesions. The initial lesions become atrophic and scar; no new lesions erupt. In one third of patients, choroidal neovascularization develops at the site of the scar; thus, visual prognosis is variable.
  • Another related condition to MCP is DSF. In these cases, in addition to the presence of multifocal choroiditis, a prominent fibrosis exists. The fibrosis is predominantly at the area of previous inflammatory lesions, and a turbid, subretinal fluid that overlies the lesions also is present. This disease is rare, and the visual prognosis is poor.
  • Both PIC and DSF represent a spectrum of disease as it relates to MCP. PIC represents a milder form of disease, while DSF is a more severe form.

Birdshot Retinochoroidopathy

  • Also known as vitiliginous choroiditis
  • typically affects females in the fourth to fifth decade of life.
  • Patients present with a painless gradual blurring of vision, floaters, and loss of color vision.
  • More than 90% of patients with birdshot chorioretinopathy are HLA-A29 positive.
  • Ocular findings include multiple depigmented yellow-white patches scattered throughout the fundus.
  • These lesions radiate from the optic nerve and follow the larger choroidal vessels. The term "birdshot" is given because the pattern of the lesions in the fundus is similar to the shotgun scatter of a birdshot.
  • Vitritis, optic disc edema, and cystoid macular edema also may be present.
  • Diagnosis is by clinical examination, fluorescein angiography, and HLA-A29 status.
  • Fluorescein angiography demonstrates mild hyperfluorescence and staining in the late phase.
  • The pathogenesis is unknown at this time; however, speculation exists regarding an autoimmune etiology.
  • Ocular and systemic corticosteroids are generally the treatment of choice.
  • is a chronic disease with multiple recurrences, and, consequently, the long-term visual prognosis generally is guarded.

Presumed Ocular Histoplasmosis Syndrome

  • POHS usually occurs in endemic areas of Histoplasma capsulatum, which includes the Ohio and Mississippi River Valley.
  • Typically, adults in the fourth decade of life are affected.
  • No sexual predilection exists.
  • Patients may be asymptomatic or may present with visual decline and a central scotoma.
  • On ocular examination, the vitreous is clear with no evidence of inflammation.
  • Typically, peripapillary atrophy, atrophic chorioretinal lesions, and choroidal neovascularization are present.
  • The lesions, which are yellow in color and resemble punched-out lesions, also may be present in the macula. Linear streaks in the midperiphery are found in a minority of the patients.
  • The pathogenesis is presumed to be due to H capsulatum; however, the organism has never been isolated from the choroid.
  • Fluorescein angiography shows the typical features of choroidal neovascularization, ie, early lacy hyperfluorescence with late leakage. Management of this condition includes argon laser photocoagulation for extrafoveal choroidal neovascularization, while krypton laser photocoagulation is beneficial for juxtafoveal choroidal neovascularization.

Controversy exists involving the white dot syndromes; some have stated that because of the significant overlap among them, the various white dot syndromes may just represent a spectrum of the same disease. For example, women have a predilection for multifocal choroiditis, PIC, and MEWDS. Occasionally, patients have presented with findings consistent with a specific syndrome; then, they later developed findings that led to the diagnosis of a different white dot syndrome. Although controversy may exist in the artificial classification of these syndromes, it is clear that an accurate diagnosis needs to be attained in all cases to ensure appropriate management may be undertaken.

Thursday, October 15, 2009

Dry eye/eczema

http://www.athealth.com/consumer/disorders/eczema.html

  • Atopic dermatitis is often referred to as "eczema," which is a general term for the several types of dermatitis (inflammation of the skin. )
  • Is a chronic (long-lasting)
  • Not contagious
  • Emotional factors, such as stress, can make the condition worse, but they do not cause the disease
Types of Eczema (Dermatitis)

  • Allergic Contact Eczema (dermatitis): A red, itchy, weepy reaction where the skin has come into contact with a substance that the immune system recognizes as foreign, such as poison ivy or certain preservatives in creams and lotions.
  • Atopic Dermatitis: A chronic skin disease characterized by itchy, inflamed skin.
  • Contact Eczema: A localized reaction that includes redness, itching, and burning where the skin has come into contact with an allergen (an allergy-causing substance) or with an irritant such as an acid, a cleaning agent, or other chemical.
  • Dyshidrotic Eczema: Irritation of the skin on the palms of hands and soles of the feet characterized by clear, deep blisters that itch and burn.
  • Neurodermatitis: Scaly patches of the skin on the head, lower legs, wrists, or forearms caused by a localized itch (such as an insect bite) that become intensely irritated when scratched.
  • Nummular Eczema: Coin-shaped patches of irritated skin-most common on the arms, back, buttocks, and lower legs-that may be crusted, scaling, and extremely itchy.
    Seborrheic Eczema: Yellowish, oily, scaly patches of skin on the scalp, face, and occasionally other parts of the body.
  • Stasis Dermatitis: A skin irritation on the lower legs, generally related to circulatory problems.
Skin Features of Atopic Dermatitis

  • Atopic Pleat (Dennie-Morgan fold): An extra fold of skin that develops under the eye.
  • Cheilitis: Inflammation of the skin on and around the lips.
  • Hyperlinear Palms: Increased number of skin creases on the palms.
  • Hyperpigmented Eyelids: Eyelids that have become darker in color from inflammation or hay fever.
  • Ichthyosis: Dry, rectangular scales on the skin.
  • Keratosis Pilaris: Small, rough bumps, generally on the face, upper arms, and thighs.
  • Lichenification: Thick, leathery skin resulting from constant scratching and rubbing.
  • Papules: Small raised bumps that may open when scratched and become crusty and infected.
  • Urticaria: Hives (red, raised bumps) that may occur after exposure to an allergen, at the beginning of flares, or after exercise or a hot bath.
Patient education:

  • Stop after shave, cologne, perfume or makeup on or near the face, (there are so many chemicals in those products it blends into an unidentifiable soup on your skin.
  • Switch to plain water to wash your face or a simple non-soap facial cleanser, shampoo, body wash.
  • If you shave, use witch hazel to close the pores and refresh your skin.
  • Switch to perfume-free products for anything that comes near your skin including laundry soap and dryer sheets.
  • Be careful with hair products near your eyes. (The skin around the eyes is extremely sensitive to soaps, conditioners, silicone hair sprays, and other hair products. )
  • When you wash and rinse your hair, let the soap and water run towards the back of the scalp rather than over your face.
  • DON'T RUB YOUR EYES!
  • Warm Compresses. Rinse a clean washcloth with warm water and wring out thoroughly. Place the folded washcloth over the eyes for about 3 minutes, twice a day, setting a timer helps. The warmth helps to loosen the oil glands that lubricate the eyeballs. This is essential if you have dry eye, meibomitis or blepharitis.
  • Eyelid cleansing. TheraTears SteriLid Eyelid Cleanser twice a day. Make sure your hands are clean before using it. Place it gently on the eyelids, massage very lightly to remove debris, and leave it on for a full minute. It takes away any pollens and debris that builds up. My eyes always feel freshened after using SteriLid.
  • Face Cream. e.g Aveeno (extra moisturizing non-scented skin relief formula). Use the cream every time after you wash your face.
  • Eye Drops.
  • Eye Ointments. Use as soon as any irritation is felt. Give it a good hour to two and the itching inevitably goes away. I never use it for more than a few days a time
  • Drink lots of water to keep hydrated and flush impurities out of your system.
  • Restasis

Supplements:

  • Vitamin A (Fish oil, yellow and green fruit and vegetables),
  • essential fatty acids (hemp seed, flax, pumpkin oil)
  • Vitamin B complex
  • Vitamin E topical oil

http://www.healthy.net/scr/article.asp?Id=2866

  • Antioxidants (vitamins A, C, E and selenium). Ensuring that your diet is rich with these well-known free-radical scavengers can help support the body’s defences against the daily chemical onslaught. Vitamin C strengthens the skin; vitamin E improves skin healing; and vitamin A helps to regulate the rapid turnover of skin cells seen in eczema. The trace mineral selenium plays a crucial role in the glutathione-peroxidase system (the body’s natural antioxidant process) and is effective for detoxing heavy metals. Suggested dosages: vitamin C, 1000 mg twice daily; vitamin E, 400 IU/day; vitamin A, 5000-10,000 IU/day; selenium, 50-200 mcg/day
  • B vitamins. B3 (niacin) and B6 (pyridoxine) are both integral to the process of new cell formation, and play a key role in the healthy function of body tissue - especially skin, which has a quick rate of turnover. A deficiency of these vitamins has been linked to various types of eczema and other skin disorders. Suggested dosages: B3, 100-500 mg/day; B6, 50-100 mg/day
  • Gamma-linolenic acid (GLA), an omega-6 fatty acid found naturally in borage (starflower), evening primrose and blackcurrant oils, could help to improve the roughened skin seen with eczema, as well as keep inflammation under control (Am J Clin Nutr, 2000; 71 [1 Suppl]: 367-72S). One study gave 3 g/day of GLA for 28 days to children with atopic eczema; although none were completely cured, all experienced improvement in their symptoms and a reduced need for medication (J Int Med Res, 1994; 22: 24-32). Suggested dosage: 2-3 g/day
  • Omega-3 fatty acids. These essential fatty acids have recognised anti-inflammatory properties. A double-blind study found that atopic eczema patients given 10 g of fish oil for 12 weeks all achieved a reduction in itching, scaling and other eczema symptoms (J Intern Med Suppl, 1989; 225: 233-6). Suggested dosage: 1000 mg three times daily
  • Zinc. A deficiency in this essential mineral is common among people with allergies, and may play a role in the development of recurring or chronic eczema (Br J Dermatol, 1984; 111: 597-601). One team of Hungarian researchers found that zinc supplementation reduced the severity of eczema symptoms in children (Orv Hetil, 1989; 130: 2465-9). Suggested dosage: 15 mg/day of zinc with 2 mg of copper (as zinc is known to deplete the body’s copper reserves)

Management tips of the week

http://www.optometric.com/om_mtotw.aspx

Thursday, October 8, 2009

Benign eyelid myokymia



  • precipitating factors such as fatigue, stress and excessive caffeine/alcohol/nicotine intake may result in irritation of the orbicularis’ nerve fibers

  • Medical-ocular history should be comprehensive and should include such questioning as antipsychotic medication usage, past CN VII palsy and prior injection in or around the eye

  • Patients should be observed for overt eyelid twitching in isolation, associated with speaking or accompanying facial/neck/limb involvement.

  • Anterior segment biomicroscopy will demonstrate contributory conditions such as trichiasis, blepharitis, keratitis, dry eye syndrome, corneal abrasion, recurrent corneal erosion and foreign body. In some instances, BEM will not be observed during the course of examination.

  • In these instances, superior oblique myokymia (SOM) should be ruled out. (While viewing the suspect eye under the slit lamp, the patient is directed to look down and in toward his or her nose. SOM, if present, will demonstrate subtle ocular oscillations lasting less than 10 seconds.)

  • Differential diagnosis of BEM includes blepharospasm, hemifacial spasm, Meige syndrome, aberrant regeneration of CN VII, trigeminal neuralgia, Tourette syndrome, spastic-paretic facial contracture and SOM.

  • antihistamine and antihistamine-combination products also proved successful in treating the condition.

  • severe cases of BEM, botulinum toxin A (Botox, Allergan) injection to the affected eyelid area has been used

Ophthalmic agents during pregnancy/lactation

http://www.pconsupersite.com/default.asp?ID=20040


Optometric nutrition


Unusual retinal vessels

http://www.optometry.co.uk/articles/docs/8a09ee2c4a719fd88e90e28ce345ac0e_Swann1991119.pdf

Remnants of the hyaloid system

  • Mittendorf dot
    Bergmeister’s papilla
    Vogt’s arcuate line
  • very rarely, the whole vessel being preserved from disc to lens
  • associated with persistence of the primary vitreous, coloboma and ONH hypoplasia

Cilioretinal artery

  • present in 30-40% of eyes
  • arise from the temporal optic disc in a hook-like manner, often traversing the papillomacular area
    more common in cases of optic disc pit, situs inversus, pre-papillary loops and optic disc drusen
  • in CRAO, the presence of a cilioretinal arteriole may enable some degree of central vision to be retained
Congenital tortuosity

  • more commonly involves retinal arterioles than veins
  • usually non-progressive with all other findings being normal
  • there is a progressive form which is inherited as an autosomal dominant trait and may be
    associated with retinal haemorrhages
    should bedifferentiated from that secondary to other problems, such as epiretinal membrane,
    vein occlusion and diabetes

Situs invertus

  • retinal vessels emerge from the optic disc in an anomalous direction
  • typically seen in tilted disc syndrome and also in myopic eyes
  • a dragged disc and vessels can have a similar appearance and occurs in retinopathy of prematurity

Congenital retinal macrovessel

  • a retinal vessel, usually the inferio-temporal retinal vein, is enlarged and drains an area
    superior to the macula
  • vision may be slightly reduced by the large vessel crossing the macula
  • macular cysts are more common in these patients

Pre-papillary loops

  • 95% of these vessels are arterioles, and usually originate from and return to an arteriole on or near the disc
    the loops may be small and simple or large and corkscrewed
  • many are surrounded by the white remnants of Bergmeister’s papilla
    usually unilateral with associated cilioretinal arterioles
  • fill before or with other retinal arteries on fluorescein angiography and do not leak
  • vitreous haemorrhage and occlusion of the loop have been reported

AV malformations

  • arterioles and veins communicate without an intervening capillary bed
  • may be isolated to a small arteriole and venule or be widespread involving the entire vascular tree
    intracranial and facial vascular malformations may be associated and constitute the Wyburn-Mason syndrome
    similar vascular anomalies can involve the orbit, conjunctiva, sclera and iris, and
    neovascular glaucoma can be a complication
  • should be differentiated from the phakomatosis von Hippel-Lindau’s disease
  • patients should be referred for neurological assessment

Collateral vessels

  • preformed capillaries connecting retinal, and retino-choroidal circulations
  • indicate a preceding vascular disorder which may point to a significant ocular and/or systemic disease
    unlike new vessels, they do not leak on fluorescein angiography
  • potential causes include retinal vein thrombosis and glaucoma
  • if the patient, especially a middle-aged female, has a chronic, progressive vision loss, together with a pale, swollen optic disc and a disc collateral, then optic nerve sheath meningioma is a likely cause

New vessels

  • new vessels proliferate following ischaemia in conditions such as diabetic retinopathy and central retinal vein thrombosis
  • may form on the optic disc, elsewhere in the fundus and in the anterior segment
  • delicate feathery appearance and leak fluorescein