Cataract

Definition and diagnostic criteria Cataract is defined as the clouding of the lens in the eye, leading to a decrease in vision. Diagnosis is primarily based on patient history and a clinical examination. Typically cataracts are age-related, although they can also be congenital or secondary to other conditions.

Epidemiology Cataract predominately affects the elderly. The incidence increases significantly with age; it is estimated that by the age of 65, about half of the population will have developed some degree of lens opacity. Risk factors include age, diabetes, smoking, prolonged exposure to ultraviolet light, and certain medications such as corticosteroids.

Diagnosis
Clinical features: Symptoms of cataract include blurred vision, difficulty with bright lights and glare, altered colour perception and a potential reduction in visual acuity. It’s important to differentiate these symptoms from other eye conditions like glaucoma or macular degeneration.

Investigations: Diagnosis is typically made through a comprehensive eye examination. This includes visual acuity testing, slit-lamp examination and fundoscopy. The slit-lamp examination reveals any lens opacities (cataracts), while fundoscopy assesses the retina and optic nerve. A common finding in cataract is the presence of a grey or yellowish-brown opacity in the lens.

Treatment Treatment of cataract involves surgical removal of the clouded lens, which is replaced with an artificial intraocular lens. This is generally recommended when the cataract interferes significantly with daily activities or causes other eye problems.

Suspicion of cataract in a baby or child warrants urgent ophthalmology referral.

Prognosis The prognosis for cataract surgery is generally excellent. Most patients achieve a significant improvement in visual acuity. Complications are rare but can include postoperative infection, inflammation or, in some cases, posterior capsule opacification, which may require further laser treatment.