Eye, gradual loss of vision

Probability diagnosis

Cataract

Chronic glaucoma

‘Dry’, age-related macular degeneration

Gradual retinal detachment

Diabetic retinopathy

Serious disorders not to be missed

Vascular:

• hypertensive retinopathy

• cerebromacular degeneration

Infection:

• syphilis

• onchocerciasis (filariasis)

Cancer/neoplasia:

• intraorbital tumours

• intracranial tumours

• choroid melanoma

Other:

• optic neuritis (multiple sclerosis)

• Paget disease of skull

Pitfalls (often missed)

Retinitis pigmentosa

Drug toxicity (e.g. quinine, methanol, arsenic)

Rarities:

• choroid retinitis

• vitamin A deficiency

• Leber hereditary optic atrophy

Key history

Past history including risk factors for cardiovascular disease, family history, drug history and associated symptoms or problems.

Key examination

• Visual acuity, ophthalmoscopic examination, tonometry, although early ophthalmological referral is recommended

Key investigations

Initial tests are:

• FBE

• ESR/CRP

• blood sugar

• syphilis serology (if clinically indicated).

Diagnostic tips

• Keep the big three causes in mind—cataract, chronic glaucoma and age-related macular degeneration—and refer for shared care.

• In the older patient whose cataract is not significantly improved with the pinhole test consider macular degeneration.