282 RETINA AND VITREOUS

Physical Disease

POSTERIOR SEGMENT TRAUMA There are approximately 2.4 million eye injuries each year in the United States; 40,000 patients are left with significant vision impairment. Before the 1970s, only 6% of patients suffering penetrating injuries recovered 5/200 VA or better; today, that figure is about 75%. Globe injuries may be classified as closed or open (laceration, IOFB, etc.).

Emergency evaluation: AMPLE history and physical (patient allergies and medications, past medical and history, last meal, then examination). Check the VA before touching the patient (legal concerns);

if VA is 5/200 or better, then there is a 28 -increased chance of salvaging acuity versus NLP, which has a very poor visual prognosis.

Early treatment is directed toward ocular stabilization as dictated by the injury. Late surgical goals include clear the ocular media, remove vitreous scaffold from any laceration, remove posterior hyaloid, and identify and treat retinal tears and breaks.

Late complications of globe injuries (and reasons for surgical failure): proliferative vitreoretinopathy, tractional RD, ciliary body shut down and phithis, cyclitic membrane, overwhelming injury, or infection (e.g., Bacillus).

CLOSED GLOBE INJURY Injuries may be classified as direct, such as commotio, RPE contusion, choroidal rupture, macular hole, chorioretinitis sclopetaria, ON evulsion, traumatic tears, or dialysis. Injuries may also be indirect, such as Purtscher’s disease, Terson’s syndrome, shaken baby syndrome, Valsalva’s maneuver, fat embolism, and whiplash injury. Associated conditions include contusion, lamellar laceration, superficial foreign body, hyphema, subluxated lens, vitreous hemorrhage (rule out RD; not an independent adverse prognostic factor).

Commotio retinae, Berlin’s or contusion edema: diffuse retinal whitening, not in a vascular pattern, from disruption of photoreceptor outer segments, with edema of all retinal layers; may have hemorrhage. Typically reversible, but may have late atrophy and variably decreased VA; may progress to macular hole or RPE disturbance.

Contusion of the RPE: like commotio, but no white discoloration, and RPE edema may have overlying serous RD. No early hypofluorescence on FA, but may have patchy RPE staining. Usually resolves.

Choroidal rupture: seen as a white scleral curvilinear streak concentric to the disk, generally temporal and single, with overlying retinal damage. May be from direct or indirect (anterior injury causing posterior contusion) injury with a tear in Bruch’s membrane, as it is not very elastic. May have associated hemorrhage or commotio. Fibrovascular ingrowth seals the rupture within 4 to 6 weeks. Give

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an Amsler’s grid with close follow-up, as CNVM risk is 10% within

5 years.

Traumatic macular hole: common after trauma, predisposed by the avascularity of the macula. Occurs days to years postinjury, with variably decreased VA, usually 20/70–400 (patient fixates at the edge of the hole). Unlike idiopathic macular holes, traumatic holes are usually larger (1/4–1/3 DD), sharply delimited, with a cuff of SRF; represents actual loss of retinal tissue, not just dehiscence. Classic treatment is observation, but patient may benefit from vitrectomy (85% closure, 20% improved VA); rarely leads to RRD.

Chorioretinitis sclopetaria: simultaneous rupture of retina and choroid without scleral rupture from passage of a high-velocity missile near the globe, causing coup-contrecoup injury. Characterized by poor VA with extensive hemorrhage and necrosis, and a ‘‘clawlike’’ break in Bruch’s membrane with late pigmentary changes and glial proliferation. Rarely RRD.

FAT EMBOLISM SYNDROME Present in 5% of patients with long bone fracture; fatal in 20% of severe cases, retinal lesions in 50%, mostly CWS and small blot hemorrhage (looks like Purtscher’s disease). Majority are asymptomatic.

NONACCIDENTAL TRAUMA (NAT), SHAKEN BABY SYNDROME Multiple circumpapillary retinal hemorrhages in any layer, often with Roth’s spots (indicates chronicity), CWS, perimacular folds, VH, retinoschisis, and subdural hemorrhage. Retinal injuries occur from rapid acceleratingdecelerating injury. Occurs in 30 to 40% of child abuse cases. Differential diagnosis: Purtscher’s disease, Terson’s syndrome, but is not caused by CPR.

Commonly has associated neurologic damage, intracranial hemorrhage, and seizures; seen in lethargic and irritable patients who are not septic. Also have high suspicion if you see hyphema, periorbital contusions, incompatible injuries, delay in presentation, multiple admissions to different hospitals, wounds in different stages of healing, mouth wounds, or skin burns. Also may occur in association with cultural therapies, such as hot spoon or coin burns, cupping, salting, moxibustion, and maqua (therapeutic burn).

Risks for NAT: lower socioeconomic status, irritable and sick babies (who are abused more often)

NAT masquerades: osteogenesis imperfecta, copper or vitamin A or C deficiency, congenital syphilis, and congenital sensory neuropathy. Differential diagnosis of bruises: mongolian spot, coagulopathies, malignancy (neuroblastoma), Hermansky-Pudlak syndrome, EhlersDanlos syndrome, vasculitis, and aspirin use.

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284 RETINA AND VITREOUS

No specific treatment. Document injuries with photos, and observe chain of custody. Be very specific in write-up: stay in your area of expertise, and do not comment on the rest of body.

OPEN GLOBE INJURY May be penetrating (into the globe), perforating (through the globe), or blunt rupture (sclera is weakest at limbus, under rectus muscles, and at the SO insertion and lamina cribrosa). Also can categorize as laceration (penetrating, IOFB, perforation) or rupture.

Signs of globe rupture: severe hemorrhage (chemosis, hyphema, VH), VA LP or worse, APD, shallow or deep AC, peaked pupil, IOP <5, or unable to visualize globe

Poor prognostic signs: APD, wound >10 mm, vitreous hemorrhage, wounds extending posterior to the muscle insertions. Zone 1 (cornea): better prognosis. Zone 2 (5 mm ring around cornea) and Zone 3 (posterior to Zone 2): worse prognosis.

Treatment (mnemonic: TICS) tetanus, IV antibiotics, CT scan; and shield the eye. Avoid ointment, and use only sterile drops prior to surgery. Even in overwhelming trauma try to suture what you can, and if necessary, do enucleation later to allow for psychological adjustment. For globe laceration, there is no outcome difference in waiting up to 36 hours. Once initial repair is completed, if secondary surgery is needed, usually wait at least 7 days for vitrectomy but not later than 14 days.

Surgery goals: determine extent of injury, restore structural integrity of globe, avoid iatrogenic damage, and decide to excise or reposit (all retina) prolapsed contents.

Surgery principles: close corneal lacerations with 10.0 nylon; fully explore scleral lacerations, excise vitreous and uvea from wound, and close with 7.0 nonabsorbable suture, but do not close small posterior wounds. Explore beneath muscle insertions, but do not insert an instrument blindly into a laceration. Prophylactic cryotherapy or scleral buckle is not recommended.

Intraocular foreign body (IOFB): 10% risk of infection, 30% if farm injury. Evaluate with x-ray or CT (not MRI).

Copper: causes chalcosis with deposits in basement membranes, causing sunflower cataract, Kayser-Fleischer ring, and retinal degeneration; may reversibly suppress the ERG. Mild inflammation from copper amalgams (often contain nickle or other metals or brass, which contains copper); higher concentration of copper causes severe suppurative endophthalmitis.

Inert foreign bodies: sand, plastic, glass, stone, and ceramic are well tolerated.

Iron: poorly tolerated; causes siderosis with deposits in epithelium, causing RPE and inner retinal degeneration (photoreceptors are spared until late). ERG early shows reduced B wave and altered loss of early receptor potential, becoming flat later.

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Wood: brisk inflammatory reaction; high risk of infection.

Zinc-aluminum: minimum inflammation; often become encapsulated.

PHOTIC, SOLAR, SUNGAZING, OR PSEUDOPHAKIC MACULOPATHY Usually bilateral if sungazing or unilateral if postoperative. Initially presents as a yellow spot in the foveola, then reddish appearance; may lead to lamellar hole (RPE rematins intact). VA usually 20/40–70 and improves over 3 to 9 months. On FA, damaged RPE may stain acutely (no leakage) and with healing leaves window defects. Reported with surgery as short as 55 minutes, from a natural ‘‘hot spot’’ of microscope light focused by the cornea and lens onto the fovea.

PURTSCHER’S RETINOPATHY From severe compression injury to the trunk, with sudden increased intrathoracic pressure with or without air or fat emboli or complement-mediated granulocyte aggregation (often coincidence with pancreatitis), causing bilateral peripapillary HE, CWS, venous congestion, few NFL hemorrhages, and occasionally ON atrophy or macular pigmentary changes. Most patients recover without visual sequelae.

RADIATION RETINOPATHY Looks like, predisposed by, and treated like diabetic retinopathy.

TERSON’S SYNDROME Twenty percent of patients with spontaneous or traumatic subarachnoid hemorrhage have sub-ILM hemorrhage that may break through into the vitreous. Vitreal or subhyaloid blood is not from direct communication with the arachnoid space but from increased venous pressure secondary to increased intracranial pressure. Usually resolves with normal VA.

TOXIC PHOTORECEPTOR RETINOPATHIES Multiple etiologies are seen:

Cardiac glycosides (digoxin, Lanoxin): used to treat congestive heart failure and arrhythmia; may cause blurred VA, yellow vision, scintillating scotomas from a direct, reversible photoreceptor toxicity; potentiated by concurrent quinidine treatment.

Sildenafil (Viagra): impotence drug that is selective inhibitor of phosphodiesterase-5 (PDE5), which modifes transduction cascade, causing a rise in cGMP. Characterized by bluish or hazy vision peaking 1 to 2 hours after ingestion in 3% of patients taking 25– 50 mg, up to 50% taking > 50 mg. No long-term visual complications.

TOXIC RPE RETINOPATHIES Drugs bind to melanin in the RPE, leading to pigmentary changes and atrophy.

Thioridazine (Mellaril): most toxic drug for the RPE, causing initial decreased central VA, with brownish discoloration of vision, and

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286 RETINA AND VITREOUS

central or ring scotoma. Characterized by initial salt and pepper fundus, followed by pigment clumping in plaquelike fashion, with later RPE atrophy. Usually safe up to 800 mg/day, and toxic if >1 g/day; maximal daily dose is more critical than accumulative dose. Needs fundoscopic exam every 6 months during administration.

Chlorpromazine (Thorazine): binds strongly to melanin, infrequent toxicity. Nonspecific fundus granularity with pigment clumping seen when dose is >800 mg/day. Also may cause pigment dusting on the lens with mild stellate cataract and brown bulbar conjunctiva deposits (pathognomic).

Chloroquine (Aralen): used as an antimalarial drug, as well as for treatment of RA and SLE. Characterized by early asymptomatic

perifoveal granularity with loss of foveal reflection (reversible), followed by ‘‘bull’s-eye’’ thinning of foveal RPE (nonreversible) and late tapetoretinal degeneration. Patients notice decreased VA with paracentral scotoma and field constriction. Maximum safe dose is 4 mg/kg/day. If total dose >300 g, 70% of patients have some degeneration, but daily dose is more critical than accumulative dose. Follow Amsler’s grid, and examine every 6 months (FA not needed routinely); may have supranormal EOG and decreased color. Can progress even after drug is discontinued.

Hydroxychloroquine (Plaquenil): significantly safer than chloroquine because it does not cross blood-retinal barrier; also used for treatment of RA and SLE. Toxic dose variable, but up to 400 mg/day is generally safe. Causes a cone dystrophy from transynaptic degeneration with classic ‘‘bull’s-eye’’ maculopathy and dyschromatopsia. Screen at least every 2 years with exam, central VF monitoring, and color plates or D-15.

Desferrioxamine: used to treat iron overload; may cause RPE alterations, cataract, and optic atrophy.

TOXIC VASCULAR RETINOPATHIES Drug causes vascular occlusion with secondary ischemic damage.

Ergot alkaloids (ergotamine, methysergide): adrenergic blockers used in migraine and postpartum hemorrhage can cause CRVO or macular edema.

Interferon-alpha retinopathy: numerous CWS, intraretinal hemorrhage, vessel occlusion, and ischemic optic neuropathy.

Oral contraceptives: less systemic thromboembolic disease today, as there is less estrogen concentration than in the past. May see disturbances in color vision, arteriolar occlusion, CRVO, retinal hemorrhage, and CME.

Quinine sulfate: antimalarial and muscle relaxant; also occasionally used as abortifactant or suicidal agent. Toxic dose is >4 g, causing blurred VA, decreased VF, nyctalopia, and photophobia. Initially

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subtle fundus findings, followed by disk pallor and vessel attenuation that resembles an old CRAO. Patients may need hemodialysis or vasodilating agents.

TOXIC EDEMATOUS RETINOPATHIES Drugs that cause CME or retinal edema.

Nicotinic acid (niacin): used in hyperlipidemia; may cause megavitaminosis and atypical CME without leakage on FA with dosage >3 g/day; reversible.

Sulfa drugs (especially chlorthalidone, Diamox, hydrochlorothiazide): drug-induced myopia from ciliary body edema, with anterior movement of the lens–iris diaphragm, or transient CME with retinal or choroidal folds.

TOXIC CRYSTALLINE RETINOPATHIES Drugs cause deposition of intraretinal crystals.

Methoxyflurane (Penthrane): anesthetic may cause secondary hyperoxalosis with calcium oxalate crystals in the RPE and inner retina; resembles flecked retina (pisciform throughout the posterior pole); may also have renal failure.

Tamoxifen (Nolvadex): antiestrogen used in breast CA; 1 to 6% of cases develop bilateral intraretinal refractile opacities (‘‘doughnut ring’’ in macula); not reported in cumulative doses <10 g. Patients may be asymptomatic to blurred VA; can continue therapy with close followup. May have cataract from blockage of chloride channels.

Talc: usually from intravenous drug abuse with end arteriole deposition, causing macular ischemia, secondary NV, or choroidal infarction.

Canthaxanthine (Orobronze, Riviera): carotenoid use in food coloring; also found in mushrooms and sometimes used as suntanning agent. Yellow, birefringent, glistening crystals in ‘‘doughnut’’ ring in the macular RPE.

Nitrofurantoin (Macrodantin): intraretinal crystals reported.

TRAUMATIC RETINITIS Post-trauma, patients may have RP-like RPE changes.

TRAUMATIC TEARS, RETINAL DETACHMENT OR DIALYSIS Twenty percent of RD is from trauma, usually seen in younger males (average age 28 years old). Most are closed globe injuries to lower lateral eye, with coup (inferior temporal) and contrecoup (superior nasal) pathology.

Dialysis is the most common lesion, seen as a ‘‘bucket handle’’ appearance behind the lens; 31% are inferotemporal, and 22% are superonasal. Giant retinal tears (>180 degrees) are seen in 16%.

Posterior flap tears with attached vitreous are seen in 11% of cases. Also, tears seen around lattice or meridianal folds. Most tears are

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