SUDDEN LOSS OF VISION

DR. AJAY DUDANI

MUMBAI RETINA CENTER

S V ROAD, SANTACRUZ (W)

DR. YASHESH MANIAR

SHRIKRISHNA EYE CLINIC

SHRIKRISHNANAGAR, BORIVLI (E)

Visual loss is a common complaint among patients of different ages with variable presentations. Some patients describe it as a gray-black curtain that gradually descends or as blurring, fogging, or dimming of vision. It usually lasts a few minutes but can persist for hours. Frequency varies from a single episode to many episodes during a day; it may continue for years but more often lasts from seconds to hours. Ischemia is the most common mechanism of acute visual dysfunction, and it can affect any aspect of the visual system.

VISION LOSS

Multiple conditions are associated with transient visual loss. They can be classified according to origin or pathogenesis, but for the purpose of this article, they are outlined by source.

CLASSIFICATION

Wray has classified TMVL into 3 groups based mostly on pathogenesis; they include the following:

•Type 1 is characterized by loss of all or a portion of vision in one eye, lasting seconds to minutes, with full recovery. It is usually secondary to embolic phenomenon. Attacks have been correlated with vessels without critical narrowing but with ulceration.

•Type 2 includes visual loss due to hemodynamically significant, occlusive, low-flow lesions in the ICAs or the ophthalmic arteries. Symptoms are brief but frequent, less rapid in onset, and longer in duration with gradual recovery.

•Type 3 is believed to be due to vasoconstriction or vasospasm.

The central retinal artery, a branch of the ophthalmic artery, enters the eye through the optic disc and divides into multiple branches to perfuse the inner layers of the retina. A branch retinal artery occlusion (BRAO) occurs when one of these branches of the arterial supply to the retina becomes occluded.

Branch Retinal Artery Occlusion

•In elderly patients, embolic disease is the most common etiology of a BRAO. In a study of 70 patients with retinal emboli, 40 were found to have cholesterol emboli, 8 platelet-fibrin emboli, 6 calcific emboli, and 1 possible myxomatous embolus. These types of emboli can also be iatrogenically displaced during cardiac angiography, catheterization procedures, or any interventional embolization of any branch of the carotid artery.

Causes

•Types of emboli (endogenous and exogenous) include the following:

•Cholesterol – Atheromatous plaques from the aorto-carotid system

Platelet-fibrin – Carotid or cardiac thrombosis

Calcific - Calcified cardiac valves and atheromatous plaques of the carotid artery

Leukoemboli - Vasculitis, Purtscher retinopathy, septic endocarditis

Fat emboli - Following long bone fractures

Amniotic fluid emboli - Complication of pregnancy

Tumors - Atrial myxoma, mitral valve papillary fibroelastoma

Talc emboli - Long-term intravenous drug abusers

Corticosteroid emboli - Complication of intralesional or retrobulbar steroid injection 

Air emboli – Following trauma or surgery

Synthetic particles – From synthetic materials used in artificial cardiac valves and other vascular procedures; facial dermal filler (Restylane) 

•Nonembolic causes of BRAO

•Thrombosis - Atherosclerosis, chemotherapeutic agents, bone marrow transplants

Inflammatory conditions – Syphilis, toxoplasma, retinochoroiditis, Behçet disease, Lyme disease, pseudotumor cerebri, Bartonella infection, HIV infection, posterior scleritis, varicella-zoster infection, multifocal retinitis with optic nerve edema, West Nile virus infection

Vasospasm – Migraines, cocaine abuse, sildenafil citrate use

Coagulopathies - Sickle cell disease, Hodgkin disease, pregnancy, anemia, platelet and clotting factor abnormalities, protein C, protein S, antithrombin III, factor V Leiden deficiencies, oral contraceptives, homocystinuria, antiphospholipid syndrome, chelation therapy

Autothrombosis- From a ruptured arteriolar macroaneurysm

Compression - Preretinal arterial loops, vitrectomy surgery, trauma

Idiopathic - A syndrome of recurrent episodes of multiple BRAOs in otherwise healthy individuals has been described. An association with Susac syndrome (microangiopathy of brain, retina, and cochlea) has been seen in some of these patients.

Lab Studies•ESR

•Antitreponemal antibody, antiphospholipid antibody,  antinuclear antibody, rheumatoid factor, serum protein electrophoresis, hemoglobin electrophoresis, prothrombin time/activated partial thromboplastin time (PT/aPTT), fibrinogen, protein C and S, antithrombin III, and factor V Leiden.

•CBC to evaluate anemia, polycythemia, and platelet disorders

•Fasting blood sugar, glycosylated hemoglobin, cholesterol, triglycerides, and lipid panel to evaluate for atherosclerotic disease

•Blood cultures to evaluate for bacterial endocarditis and septic emboli

Imaging Studies

•Fluorescein angiography

•Optical coherence tomography (OCT)

•Electroretinogram (ERG)

•Serial Humphrey visual field testing

inferior branch retinal artery occlusion from a platelet-fibrin embolus. There is retinal whitening surrounding the occluded artery.

Optical coherence tomography (OCT)

Medical Care

Considering the increased rate of mortality, patients with BRAO should receive a full medical workup with special attention to the cerebrovascular and cardiovascular system. Depending on the findings, carotid endarterectomy or anticoagulation may be indicated. Lab workup for coagulopathies should also be performed if no embolic source is found.

Further Outpatient Care

•Patients should initially be evaluated every 3-6 months to monitor progression. Ocular neovascularization after BRAO is rare. If neovascularization occurs, panretinal photocoagulation should be performed.

Prognosis

•Recovery from BRAO is usually very good without treatment; 80-90% of patients improve to a visual acuity of 20/40 or better. However, some degree of visual field deficit usually persists.

•The Eye Disease Case-Control Study reported the following findings:

•Systemic hypertension is a risk factor for BRVO.

•Diabetes mellitus and open-angle glaucoma are not risk factors for BRVO.

•Moderate alcohol consumption reduces the risk of BRVO.

•Patients often complain of a sudden painless decrease of vision in the affected eye.

•Some may complain of a scotoma.

Branch retinal vein occlusion

Causes

•Most cases of BRVO are due to idiopathic factors. Usually, patients have an anatomical predisposing factor, such as an arteriovenous crossing where the artery compresses the vein. This compression leads to clot formation and subsequent BRVO.

•Inflammatory conditions that affect the retinal veins may cause local damage that predisposes the individual to intravascular clot formation with subsequent BRVO. Some of the inflammatory conditions reported in the literature are the following:

•Sarcoidosis

•Lyme disease

•Serpiginous choroiditis

•

•Thrombophilic conditions, such as the following, may also be involved:

•Protein S deficiency

•Protein C deficiency

•Resistance to activated protein C (factor V Leiden)

•Antithrombin III deficiency

•Antiphospholipid antibody syndrome

•Lupus erythematosus

•Gammopathies

Lab Studies•The authors of the Branch Vein Occlusion Study (BVOS) have recommended against extensive testing in patients with typical BRVO.

•Certain laboratory studies may be useful in atypical cases (ie, bilateral cases, those in young patients, those in patients with a personal or family history for thromboembolism). Determinations of the following may be helpful: 

•Prothrombin time (PT) and activated partial thromboplastin time (aPTT)

•Protein C, protein S, factor V Leiden, and antithrombin III

•Homocysteine

•Antinuclear antibody (ANA), lupus anticoagulant, and anticardiolipin

•Serum protein electrophoresis (SPEP) results

Imaging Studies•Fluorescein angiography

A fluorescein angiogram is obtained as soon as the hemorrhages have cleared if the patient's vision is still depressed. The test is usually done 3 months after the event.

The purpose is to determine the cause of the visual loss (eg, macular edema, macular ischemia). If the visual loss is secondary to macular edema, laser photocoagulation in a grid pattern may be of benefit. Conversely, if macular ischemia is responsible for the visual loss, laser photocoagulation should not be offered.

Optical coherence tomography (OCT): Given its ability to measure retinal thickness in a quantitative fashion, OCT is a useful adjunct in the follow-up of patients with macular edema secondary to BRVO.

Complications

•Macular edema

•Retinal neovascularization

•Vitreous hemorrhage

•Tractional retinal detachment

•Rubeosis iridis

•Epiretinal membrane

Prognosis

•An analysis of several series indicates that 53% of eyes obtain 20/40 or better visual acuity, 25% have a visual acuity between 20/50 and 20/100, and 22% have a visual acuity of 20/200 or worse.

•The more distal the occlusion is from the optic disc, the better the visual prognosis.

Central Retinal Artery Occlusion

Background: In 1859, Van Graefe first described central retinal artery occlusion (CRAO) as an embolic event to the central retinal artery in a patient with endocarditis. In 1868, Mauthner suggested that spasmodic contractions could lead to retinal artery occlusion. There is a multitude of causes of CRAO, but patients typically present with sudden, severe, and painless loss of vision.

History •The most common presenting complaint is an acute, persistent, painless loss of vision in the range of counting fingers to light perception in 90% of patients. Consider ophthalmic artery occlusion if visual acuity is worse.

•Some patients may reveal a history of amaurosis fugax involving transient loss of vision lasting seconds to minutes but which may last up to 2 hours. The vision usually returns to baseline after an episode of amaurosis fugax.

•Ask about symptoms of temporal arteritis in the older population. Patients complain of sudden, painless, nonprogressive vision loss in one eye. History of headaches, jaw claudication, scalp tenderness, proximal muscle and joint aches, anorexia, weight loss, or fever may be elicited.

•Ask about any medical problems that could predispose to embolus formation (eg, atrial fibrillation, endocarditis, coagulopathies, atherosclerotic disease, hypercoagulable state).

•Prolonged direct pressure to the globe during drug-induced stupor or improper positioning during surgery may lead to CRAO.

•Ask about drug history.

Physical •Determine the degree of vision loss (eg, no light perception, hand movement, counting fingers).

•Ocular examination includes the following:

•Check for afferent pupillary defect.

•Perform an optic nerve examination to look for signs of temporal arteritis. Critical signs include afferent pupillary defect, pale/swollen optic nerve with splinter hemorrhages.

•Cherry-red spot and a ground-glass retina may take hours to develop.

•The funduscopic findings typically resolve within days to weeks of the acute event, sometimes leaving a pale optic disc as the only physical finding.

•Emboli can be seen in about 20% of patients with CRAO.

•Boxcar segmentation can be seen in both arteries and veins. This is a sign of severe obstruction.

•Perform a cardiovascular examination for murmurs or carotid bruits.

•Perform a systemic examination for temporal tenderness, jaw claudication, muscle weakness, and fever to evaluate for temporal arteritis.

Causes of CRAO vary depending on the age of the patient. A detailed analysis of comorbid disease is necessary to elucidate the cause of the acute visual loss.

•Systemic hypertension seen in two thirds of patients

•Diabetes mellitus

•Cardiac valvular disease seen in one fourth of patients

•Cardiac anomalies such as patent foramen ovale

Causes

•Embolism

•Most commonly cholesterol but can be calcific, bacterial, or talc from intravenous drug abuse

•Associated with poorer visual acuity and higher morbidity and mortality

•Emboli from the heart are the most common cause of CRAO in patients younger than 40 years.

•Amaurosis fugax preceding persistent loss of vision suggests branch retinal artery occlusion (BRAO) or temporal arteritis and may represent emboli causing temporary occlusion of the retinal artery.

•Coagulopathies from sickle cell anemia or antiphospholipid antibodies are more common etiologies for CRAO in patients younger than 30 years.

•Atherosclerotic changes

•Carotid atherosclerosis is seen in 45% of cases of CRAO, with 60% or greater stenosis in 20% of cases.

•Atherosclerotic disease is the leading cause of CRAO in patients aged 40-60 years.

•Giant cell arteritis

•Consider in patients older than 65 years, but do not ignore in younger patients

•May produce CRAO or ischemic optic neuropathy

•Treat to preserve fellow eye

•Hypercoagulable state

•Collagen vascular disease

•Oral contraceptives

•Polycythemia

•Polyarteritis nodosa

•Rare causes

•Consider in younger patients

•Behçet disease

•Syphilis

•Sickle cell disease

•Migraine

•Hydrostatic arterial occlusion

•Increased intraocular pressure from glaucoma or prolonged direct pressure to the globe in unconscious patients can precipitate CRAO.

Lab Studies•Laboratory studies are helpful in determining the etiology of CRAO.

•CBC to evaluate anemia, polycythemia, and platelet disorders

•Erythrocyte sedimentation rate (ESR) evaluation for giant cell arteritis

•Fibrinogen, antiphospholipid antibodies, prothrombin time/activated partial thromboplastin time (PT/aPTT), and serum protein electrophoresis to evaluate for coagulopathies

•Fasting blood sugar, cholesterol, triglycerides, and lipid panel to evaluate for atherosclerotic disease

•Blood cultures to evaluate for bacterial endocarditis and septic emboli

Imaging Studies Imaging studies are helpful in determining the etiology of CRAO.

•Carotid ultrasound imaging to evaluate atherosclerotic disease. This appears to be more sensitive than carotid Doppler, which only determines the flow.

•Magnetic resonance angiogram may be more accurate in detecting obstruction.

•Fluorescein angiogram

•Delay in arteriovenous transit time (<11 seconds is normal).

•Delay in retinal arterial filling

•Arterial narrowing with normal fluorescein transit after recanalization

Early filling of cilioretinal artery

Non-filling of other vessels Late staining of vessel walls

Imaging techniques of carotid artery

Duplex scanning• High resolution real-time B-scan ultrasonography with Doppler flow analysis

• Injection of contrast medium into superior vena cava

• Also images ischaemic cerebral lesions

Magnetic resonance angiography

• Images produced by computer- assisted subtraction techniques

• Excellent visualization• Potential morbidity

Digital intravenous subtraction angiography Intra-arterial angiography

• Seldom performed

Treatment options for carotid disease

Antiplatelet therapy• Aspirin 75 mg daily

• Aspirin + dipyridamole (Persantin)

Anticoagulants - if antiplatelet therapy ineffective

• Clopidorel (Plavix) 75 mg daily

• Patients with other risk factors for stroke• Symptomatic carotid stenosis > 70%

Carotid endarterectomy

Medical Surgical

Central Retinal Vein Occlusion

Central retinal vein occlusion (CRVO) is a common retinal vascular disorder. Clinically, CRVO presents with variable visual loss; the fundus may show retinal hemorrhages, dilated tortuous retinal veins, cotton-wool spots, macular edema, and optic disc edema. In view of the devastating complications associated with the severe form of CRVO, a number of classifications were described in the literature. All these classifications take into account the area of retinal capillary nonperfusion and development of neovascular complications.

2 clinical types

ischemic and nonischemic

Nonischemic CRVO is the milder form of the disease. It may present with good vision, few retinal hemorrhages and cotton-wool spots, no relative afferent pupillary defect, and good perfusion to the retina. Nonischemic CRVO may resolve fully with good visual outcome or may progress to the ischemic type.

Ischemic CRVO is the severe form of the disease. CRVO may present initially as the ischemic type, or it may progress from nonischemic. Usually, ischemic CRVO presents with severe visual loss, extensive retinal hemorrhages and cotton-wool spots, presence of relative afferent pupillary defect, poor perfusion to retina, and presence of severe electroretinographic changes. In addition, patients may end up with neovascular glaucoma and a painful blind eye.

hemorrhages extending all over the fundus -same patient

Clinical features

Patients should undergo a complete eye examination, including visual acuity, pupillary reactions, slit lamp examination of the anterior and posterior segments, undilated examination of the iris, gonioscopy, fundus examination with indirect ophthalmoscope, and fundus contact lens.

•Visual acuity: Best-corrected vision always should be obtained. It is one of the important indicators of final visual prognosis.

•Pupillary reactions may be normal and may present with relative afferent pupillary reflex. If iris has abnormal blood vessels, pupil may not react.

•Conjunctiva: Advanced stages may show congestion on conjunctival and ciliary vessels.

•Cornea: Advanced stages may show diffuse corneal edema obscuring the visibility of internal structures.

•Iris may be normal. Advanced stages may show neovascularization. These vessels are detected best on an undilated iris. Initially, vessels may be seen around pupillary margins and peripheral iridectomy openings if present.

Fundus examination

•Retinal hemorrhages may present in all 4 quadrants.

•Hemorrhages can be superficial, dot and blot, and/or deep.

•In some patients, hemorrhages may be seen in peripheral fundus only.

•Hemorrhages can be mild to severe, covering the whole fundus giving a "blood and thunder appearance."

•Dilated tortuous veins: Veins may be dilated and tortuous.

•Optic disc edema: Optic disc may be swollen during early stage disease.

•Cotton-wool spots are more common with nonischemic CRVO. Usually, they are concentrated around the posterior pole. Cotton-wool spots may resolve in 2-4 months.

•Neovascularization of the disc

•Fine abnormal neovascularization on the disc (NVD) or within 1 disc diameter from the disc may be present.

•NVD indicates severe ischemia of the retina.

•Sometimes NVD is difficult to differentiate from optociliary shunt vessels.

•NVD can lead to preretinal or vitreous hemorrhage.

•Neovascularization elsewhere

•Neovascularization elsewhere (NVE) is not as common as NVD.

•NVE indicates severe ischemia of the retina.

•NVE can lead to preretinal or vitreous hemorrhage.

•Optociliary shunt vessels are abnormal blood vessels on the disc, directing blood from retinal circulation to choroidal circulation, which indicate good compensatory circulation.

•Preretinal or vitreous hemorrhage

•Macular edema with or without exudates

•Cystoid macular edema

•Lamellar or full-thickness macular hole

•Optic atrophy

•Pigmentary changes in the macula

Causes

Central retinal vein obstruction has been associated with various systemic pathological conditions, although the exact cause and effect relationship has not been proven. Some of the conditions in which CRVO has been associated include the following:

•Systemic vascular disease

•Hypertension

•Diabetes mellitus

•Cardiovascular disease

•Blood dyscrasias

•Polycythemia vera

•Lymphoma

•Leukemia

•Clotting disorders

•Activated protein C resistance

•Lupus anticoagulant

•Anticardiolipin antibodies

•Protein C

•Protein S

•Antithrombin III

•Paraproteinemia and dysproteinemias

•Multiple myeloma

•Cryoglobulinemia

•Vasculitis

•Syphilis

•Sarcoidosis

•Autoimmune disease - Systemic lupus erythematosus

•Oral contraceptive use in women

•Other rare associations

•Closed-head trauma

•Optic disc drusen

•Arteriovenous malformations of retina

•The Eye Disease Case-Control Study Group reported that risk of CRVO is decreased in men with increasing level of physical activity and increasing levels of alcohol consumption. The same study group reported decreased risk of CRVO with use of postmenopausal estrogens and increased risk with higher erythrocyte sedimentation rates in women.

•Lymphoma

•Leukemia

•Clotting disorders

•Activated protein C resistance

•Lupus anticoagulant

•Anticardiolipin antibodies

•Protein C

•Protein S

•Antithrombin III

•Paraproteinemia and dysproteinemias

•Multiple myeloma

•Vasculitis

•Cryoglobulinemia

•Syphilis

•Sarcoidosis

•Autoimmune disease - Systemic lupus erythematosus

•Oral contraceptive use in women

•Other rare associations

•Closed-head trauma

•Optic disc drusen

•Arteriovenous malformations of retina

Optical coherence tomography•Optical coherence tomography (OCT) scanning is a noninvasive, noncontact, transpupillary imaging technology that can image retinal structures in vivo with a resolution of 10-17 µm. OCT quantitatively measures the retina in micrometers in situ and in real time.

•OCT can detect even subtle macular edema in the presence of significant hemorrhages, which is not evident by fluorescein angiography because of blockage from hemorrhage.

•OCT is useful in quantitatively monitoring the development of macular edema and resolution with treatment.

Fluorescein angiography

•most useful test for the evaluation of retinal capillary nonperfusion, posterior segment neovascularization, and macular edema.

Medical Care

No known effective medical treatment is available for either prevention or the treatment of CRVO. Identifying and treating any systemic medical problems to reduce further complications is important. Because the exact pathogenesis of the CRVO is not known, various medical modalities of treatment have been advocated by multiple authors with varying success in preventing complications and preserving vision.

TREATMENT•Aspirin

•Anti-inflammatory agents

•Isovolumic hemodilution

•Plasmapheresis

•Systemic anticoagulation with warfarin, heparin, and alteplase

•Fibrinolytic agents

•Systemic corticosteroids

•Local anticoagulation with intravitreal injection of alteplase

Intravitreal injection of triamcinolone•In patients with macular edema, injection of triamcinolone (0.1 mL/ 4 mg) into the vitreous cavity through pars plana has been shown to be effective not only in resolving the edema but also in corresponding improvement in vision.

•Even though the exact mechanism of action of intravitreal injections of corticosteroids is not known, the triamcinolone crystals in the vitreous cavity probably reduce VEGF concentrations in the vitreous cavity. This leads to a reduction in capillary permeability and macular edema. The main drawback of an injection of triamcinolone was posttreatment recurrences of macular edema, requiring repeat triamcinolone injections, typically every 3-6 months.

Laser photocoagulation is the known treatment of choice in treatment of various complications associated with retinal vascular diseases (eg, diabetic retinopathy, branch retinal vein occlusion). Panretinal photocoagulation (PRP) has been used in the treatment of neovascular complications of CRVO for a long time. However, no definite guidelines exist regarding exact indication and timing of PRP. A National Eye Institute sponsored multicenter prospective study, the Central Vein Occlusion Study (CVOS), gave guidelines for treatment and follow-up care of patients with CRVO.

•Chorioretinal venous anastomosis

•Radial optic neurotomy

•Vitrectomy

Retinal detachment (RD) Separation of sensory retina from RPE by subretinal fluid (SRF)

Rhegmatogenous - caused by a retinal break

Non-rhegmatogenous - tractional or exudative

•Papilledema/neoplasm causes visual loss by mechanically compressing or physiologically destroying the optic nerve. If confined to the orbits, vision is affected unilaterally with a decline in central acuity, dyschromatopsia, and an afferent pupillary defect in most instances. Visual field defects involve central/paracentral and arcuate scotomas, nasal steps, or temporal wedges. Funduscopy shows a swollen, pale, or normal retina.

Papilloedema/neoplasm

Trauma

Hyphema

Ruptured globe •A ruptured globe results from a full-thickness traumatic disruption of the sclera or the cornea as a result of blunt or penetrating trauma to the eye. Open globe should be suspected in any patient who has a history of trauma to the eye, especially with a laceration or puncture wound that extends through the eyelid, followed by pain and decreased visual acuity.

Anterior segment complications of blunt trauma

Sphincter tear

Cataract Angle recession

Hyphaema

Lens subluxation

Iridodialysis Vossius ring

Rupture of globe

Macular hole Optic neuropathyEquatorial tears

Posterior segment complications of blunt trauma

Choroidal rupture and haemorrhageCommotio retinae Avulsion of vitreous base

and retinal dialysis

Complications of penetrating trauma

Flat anterior chamber

Vitreous haemorrhage

Damage to lens and iris

EndophthalmitisTractional retinal detachment

Uveal prolapse

Vitreous hammorhage

Eale’s disease

Optic Neuritis, Childhood

Optic neuritis implies an inflammatory process involving the optic nerve. In children, most cases are due to an immune-mediated process. These cases may be associated with a viral or other infection or with immunization

Optic neuritis may be the first manifestation of multiple sclerosis (MS) or part of a more diffuse demyelinating disorder, including acute disseminated encephalomyelitis or Devic disease.

Optic neuritis may be related to specific infections, diseases of the adjacent sinuses or orbital structures, and infectious and infiltrative diseases of the brain or meninges that involve the optic nerves.

Optic Neuritis

The following definitions aid in further understanding optic neuritis:

Papillitis - Optic neuritis involving the optic disc with disc edema

Retrobulbar optic neuritis - Optic neuritis involving the optic nerve behind the globe. The optic disc appearance should be normal in first-time episodes of retrobulbar optic neuritis.

Bilateral simultaneous optic neuritis - Optic neuritis in both eyes occurring within 3 weeks of each other

Bilateral sequential optic neuritis - Optic neuritis occurring in both optic nerves but separated by a period of more than 3 weeks

OPTIC NEUROPATHIES

1. Clinical features

2. Special investigations

5. Leber hereditary optic neuropathy

3. Optic neuritis

4. Anterior ischaemic optic neuropathy (AION)

• Retrobulbar neuritis• Papillitis• Neuroretinitis

Signs of optic nerve dysfunction

• Reduced visual acuity

• Diminished light brightness sensitivity

• Dyschromatopsia

• Afferent pupillary conduction defect

Applied anatomy of afferent conduction defect

Anatomical pathway Signs• Equal pupil size

• Light reaction - ipsilateral direct is absent or diminished - consensual is normal

• Near reflex is normal in both eyes

• Total defect (no PL) = amaurotic

pupil

• Relative defect = Marcus

Gunnpupil

3rd

Visual field defectsCentral scotoma

Altitudinal Nerve fibre bundle

Centrocaecal scotoma

Optic disc changes

• Retrobulbar neuritis• Early compression

Normal

• Papilloedema• Papillitis and neuroretinitis

Swelling

• Optic nerve sheath meningioma• Occasionally optic nerve glioma

Optico-ciliary shunts

• Postneuritic• Compression

Atrophy• AION

• Hereditary optic atrophies

Special investigations

Orbital fat-suppression techniques in T1-weighted images

Assessment of electrical activity ofvisual cortex created by retinal stimulation

MRI Visually evoked potential

Classification of optic neuritis

Retrobulbar neuritis (normal disc)

• Demyelination - most common

• Sinus-related (ethmoiditis)

• Lyme disease

Papillitis (hyperaemia and oedema)

• Viral infections and immunization in children (bilateral)

• Demyelination (uncommon)

• Syphilis

Neuroretinitis (papillitisand macular star)

• Cat-scratch fever

• Lyme disease

• Syphilis

Non-arteritic AION

• Pale disc with diffuse or sectorial oedema

• Eventually bilateral in 30% (give aspirin)

• Age - 45-65 years• Altitudinal field defect

Presentation

Acute signs

• Few, small splinter-shaped haemorrhages• Resolution of oedema and haemorrhages

• Optic atrophy and variable visual loss

Late signs

FA in acute non-arteritic AION

Generalized hyperfluorescenceIncreasing localizedhyperfluorescence

Localized hyperfluorescence

Superficial temporal arteritis

• Headache

• Age - 65-80 years• Scalp tenderness

Presentation

• Superficial temporal arteritis

• Jaw claudication• Polymyalgia rheumatica

• Temporal artery biopsy

• ESR - often > 60, but normal in 20%

• C-reactive protein - always raised

Special investigations• Acute visual loss

Histology of giant cell arteritis

• High-magnification shows giant cells• Granulomatous cell infiltration

• Disruption of internal elastic lamina

• Proliferation of intima

• Occlusion of lumen

Arteritic AION• Affects about 25% of untreated patients with giant cell arteritis

• Severe acute visual loss• Treatment - steroids to protect fellow eye

• Bilateral in 65% if untreated

• Pale disc with diffuse oedema• Few, small splinter-shaped haemorrhages• Subsequent optic atrophy

Leber hereditary optic neuropathy

Maternal mitochondrial DNA mutations

Signs• Disc hyperaemia and dilated capillaries (telangiectatic microangiopathy)

• Vascular tortuosity• Swelling of peripapillary nerve fibre layer

Presents• Typically in males - third decade• Occasionally in females - any age• Initially unilateral visual loss

• Fellow eye involved within 2 months• Bilateral optic atrophy

• Subsequent bilateral optic atrophy

Intraocular foreign bodies

•Intraocular foreign bodies are small particles that have penetrated the cornea or the sclera. This condition commonly occurs in the workplace; signs can be subtle, causing only light erythema and local discomfort. Visual acuity is often decreased markedly, but normal visual acuity is possible and does not rule out an intraocular foreign body. Smaller objects may produce few, if any, signs or symptoms and may be difficult to discover without a high index of suspicion. With large objects, obvious disruption of the anterior segment, a visible penetration site, hyphema, or cataract may be seen.

Imaging Studies:

•CT scans are the test of choice for IOFB localization. A consultation with the CT technician is helpful in selecting the optimal section so as to reduce the risk of a false-negative result. Helical CT scans have a very high identification rate.

•Plain x-ray is useful if a metallic IOFB is present and a CT scan is unavailable.

•MRI generally is not recommended for metallic IOFBs.

•Ultrasound is a useful tool in localizing IOFBs, and its careful use is possible even if the globe is still open; alternatively, intraoperative use after wound closure can be attempted. The ultrasound biomicroscope may help with IOFBs in the anterior segment.

IOFB CT SCAN

Endophthalmitis, Bacterial

Background: Bacterial endophthalmitis is an inflammatory reaction of the intraocular fluids or tissues caused by microbial organisms.

History

The clinical presentation is dependent on the route of entry, the infecting organism, and the duration of the disease. In general, patients complain of a decrease in vision, often with a red eye. Most patients also may complain of a deep ocular pain. Classification is based on routes of entry.

•Exogenous

•Endogenous

Exogenous•Acute postoperative (<6 wk postoperative)

•Usually, infection occurs 2-10 days after surgery.

•Patients present with visual loss greater than expected in the usual postoperative course.

•Ocular pain is seen in 75% of the patients.

•Use of postoperative antibiotic and anti-inflammatory drugs may blunt the severity of the disease and possibly delay medical attention.

•Delayed onset or chronic pseudophakic postoperative (>6 wk postoperative)

•Typically, patients present with mild-to-moderate inflammatory red eye, reduced vision, and photophobia.

•Chronic indolent course is present.

•Patients may be diagnosed with idiopathic uveitis and treated with topical steroids with temporary improvement.

•Rule out fungal species.

•Filtering bleb associated: Clinical features are similar to acute postoperative infection with purulent bleb involvement.

•Posttraumatic: History of trauma is present, and infection usually progresses rapidly.

Endogenous

•No recent history of ocular surgery is present.

•Confusion with delayed onset or chronic postoperative is possible if suspicion for endogenous route is not ruled out.

•Rarely bilateral.

Physical General findings

•Visual acuity decreased below the level expected

•Lid edema

•Conjunctival hyperemia

•Corneal edema

•Anterior chamber cells and flare

•Keratic precipitates

•Hypopyon

•Fibrin membrane formation

•Vitritis

•Loss of red reflex

•Retinal periphlebitis if view of fundus possible

Specific findings

•Delayed onset or chronic: Occasionally, findings display a white plaque within the equator of the remaining lens capsule.

•Filtering bleb associated: A purulent bleb is seen occasionally with areas of necrosis in the sclera from the use of antimetabolites.

•Posttraumatic: Evidence of penetrating trauma is seen with the possibility of an intraocular foreign body.

•Endogenous: Patient may appear systemically ill.

Lab Studies

•Perform culture and sensitivity studies on aqueous and vitreous samples to determine type of organism and antibiotic sensitivity.

•If endogenous bacterial endophthalmitis is suspected, a systemic workup for the source is required. This workup includes the following:

•Blood culture

•Sputum culture

•Urine culture

Imaging Studies

•Perform ultrasound of the posterior pole if view of fundus is poor.

•B-scan ultrasound

•Typically, choroidal thickening and ultrasound echoes in the anterior and posterior vitreous support diagnosis.

•Occasionally, another source of inflammation other than or in addition to bacterial such as retained lens material may be seen.

•The ultrasound is also important to provide a baseline prior to intraocular intervention and to assess the posterior vitreous face and areas of possible traction.

•Rarely, a retinal detachment is seen concurrently with endophthalmitis.

•A CT scan rarely is performed unless trauma is involved. Thickening of the sclera and uveal tissues associated with various degree of increased density in the vitreous and periocular soft tissue structures may be seen.

•If an endogenous route is considered, perform other imaging modalities to rule out potential sources.

•Two-dimensional echocardiogram

•Chest x-ray

Medical Care

Bacterial endophthalmitis is an ocular emergency and urgent treatment is required to reduce the potential of significant visual loss.

•All patients should have therapy consisting of intravitreal and topical antibiotics, topical steroids, and cycloplegics.

•The Endophthalmitis Vitrectomy Study (EVS) identified that the use of periocular and intravenous antibiotics are not required in endophthalmitis following cataract surgery. Medical therapy was found to be statistically as effective as surgical intervention when the presenting vision was hand motion or better. Use caution in interpreting the data from the EVS; apply it cautiously to non–cataract-related endophthalmitis.

•When the inflammation is severe, systemic and periocular therapy may be used in non–cataract-induced, delayed onset, filtering bleb–associated, and posttraumatic endophthalmitis.

•In endogenous endophthalmitis, systemic, topical, and possibly periocular therapy usually is required.

Surgical Care

Surgical intervention usually is performed urgently except in the delayed onset category where elective surgery may suffice.

•Indications for surgical therapy

•Acute pseudophakic postoperative - When the presenting vision is light perception or worse

•Delayed onset or chronic postoperative - If marked inflammation or a subcapsular plaque is identified, surgical removal is required.

•Filtering bleb associated - If marked inflammation is present. Take care not to disturb the bleb if some function still exists. To allow the possibility of a shunt valve to be placed at a later time, make an attempt to minimize the disturbance to the superior conjunctiva. If the patient is aphakic, performing the pars plana vitrectomy from the temporal side using a limbal approach may be required.

•Posttraumatic - If marked inflammation or rapid onset occurs

Complications

•Retinal necrosis

•Retinal detachment

•Retinal necrosis

•Vitreous tap

•Vitrectomy

•Increased intraocular pressure

•Retinal vascular occlusion

•Optic neuropathy

•Panophthalmitis

•Hypotony

•Ciliary body shut down

•Leaking wound

•Retinal detachment

•Cyclodialysis cleft

•Medication

Miscellaneous Hysteria/malingering

•Patients with hysterical blindness or loss of vision, despite alleged loss of vision, are still capable of maneuvering in a room. Pupillary reactions are normal. Loss of vision is a subconscious conversion symptom. A purely functional loss of vision can be assumed when the visual field is constricted markedly, orientation when walking is intact, and pupillary reactions to light are normal.

•A fluid transition exists between a hysterical and malingering patient and aggravated loss of vision. If the patient indicates a unilateral loss of vision, examination should be conducted in such a way that the patient does not know which eye is being tested or the actual size of the optotypes

Drugs

•Methyl alcohol poisoning

•Quinidine, sildenafil (Viagra), vardenafil (Levitra), and tadalafil (Cialis)

•Sudden monocular visual loss due to nonarteric anterior ischemic optic neuropathy (NAION) has been reported in a small number of patients taking sildenafil (Viagra), vardenafil (Levitra), and tadalafil (Cialis) for erectile dysfunction. The US Food and Drug Administration (FDA) advised health care professionals of the potential risk of sudden visual loss that may be attributed to the use of phosphodiesterase-5 (PDE-5) inhibitors.

•Idiopathic

•Migraine or scintillating scotoma may occur on a persistent basis or may recur after an absence of decades. Physiologic and anatomical bases have not been fully explained but are believed to involve vasospasm. Shimmering scotomas, with or without color or perception of movement, are commonly reported, usually lasting less than 30 minutes.