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Ophthalmology

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Retina

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57 out of 120
 

A young man presents with decreased vision in left eye. After three months, there is decreased vision in right eye. Fundus show disc telangiectasia & hyperemia with reflex normal. Most probable diagnosis is. (AIIMS May 2009)



A AION
B Leber hereditary optic neuropathy

C Papilledema
D Toxic neuropathy

Ans. B Leber Hereditary Neuropathy

(Ref: Principles and practice of Ophthalmology/Jackobeic/ 5 edition)

Leber hereditary optic neuropathy:

1. LHON is maternally inherited disease that primarily affects young males.

2. Point mutation in the NADH dehydrogenase complex genes

3. The onset typically occurs between 12-30 yrs

4. The neuropathy characterized by painless sub acute bilateral visual loss and central or centrocecal scotomas.

5. Characteristic impaired visual acuity occurs in one eye and sequential visual loss develops in contra lateral eye weeks or month’s later.

6. During acute stage, circumpapillary telangiectatic microangiopathy is present with hyperemia of the disc, swelling of peripapillary NFL, vascular tortuosity and absence of leakage from the disc or vessels in Fluorescein angiography.

Toxic Amblyopia : Toxic optic neuropathy (option D)

Refers to member of conditions in which optic nerve fibres are damaged by exogenous poisons

1. Acute painless central visual loss

2. No or little bilateral optic disc INFLAMMATION (Chronic retrobulbar neuritis)

3. Central or cecocentral scotomas

4. Causes:

a. Tobacco

b. Ethambutol*

c. Def. Of vitamin : B12

d. Ethylene glycol

e. Methyl alcohol

f. Quinine*

Papilledema (OPTION C)

Refersto bilateral optic disc swelling secondary to raised intra cranial pressure

Pathology

Due to disturbance of pressure gradient across the lamina cribrosa

Stasis of axoplasm in prelaminar area


Axonal swelling


Venous congestion


Extra cellular edema or disc edema

Etiology

1. Intracranial (B/L symmetric)

a. Hemorrhage – Subarachnoid hemorrhage (thunderclap headache) -Papilledema is earliest to develop

b. Meningitis

c. Neoplasm- glioma, meningioma,

d. Brain abscess

e. Pseudotumor cerebri (Benign intracranial hypertension)

2. Systemic

a. Malignant HTN

b. Endocrinal – hyperthyroidism, toxemia of pregnancy

3. Ocular : Secondary to hypotony

a. Ocular trauma – accidental / surgical

b. Sudden lowering of intraocular pressure (Hypotony) in cataract , RD surgery

C/F:

Ophthalmoscopic Findings

1. Blurring of disc margin

2. Hyperemia of disc

3. Swelling of optic disc ( 6 –8 D) which spills into periphery producing concentric folds in (Paton’s line)

4. Tortuous and dilated veins . Retinal hemorrhages

S/S:

1. Transient obscuration/blurring of vision(Amaurosis Fugax)

2. No decrease in VA

3. Normal colour vision

4. Normal pupillary reaction

5. Visual field – enlargement of blind spot

6. Associated symptom – headache, vomiting, diplopia on lateral gage

Anterior ischemic optic neuropathy (option a)

It is a segmental or generalized infarction within the pre laminar or laminar portion of the optic nerve caused by occlusion of posterior ciliary arteries

Classification


Arteritic Non-Arteritic

Arteritic AION

Etiology -GCA(Giant-Cell-Arteritis)

Clinical Features

1. Transient visual obscuration followed by uniocular, sudden and profound loss of vision.

2. Periocular pain. Jaw claudication

3. Pale, swollen optic nerve head surrounded by small splinter-shaped hemorrhages.

Treatment: IV Hydrocortisone with oral prednisolone.

Non - Arteritic AION

Etiology

1. Idiopathic

2. Hypertension is the major risk factor.

Clinical Features

1. Monocular, sudden and painless visual loss

2. No premonitory visual symptoms

3. Diffuse or sectorial edema with hyperemic optic nerve head surrounded by splinter-shaped hemorrhages, later the involved portion of the disk becomes pale.

4. Visual acuity in 1/3rd patients is either normal or slightly reduced. Remaining 2/3rd suffer from moderate to severe visual loss.

5. Visual field defects

1. Altitudinal hemianopia: Most commonly involves the inferior field.

2. Central Scotoma-: If there is infarction of papillomacular bundle.

6. Colour vision: It is diminished in proportion to the level of visual acuity unlike optic neuritis.

Investigations

1. Serological studies, serum lipids, blood glucose, and factors affecting viscosity.

2. To exclude occult GCA and other autoimmune diseases.

Treatment

1. Treatment of underlying disease.

2. To quit smoking and alcohol.

3. Optic nerve sheath decompression if progressive visual loss.

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