Cataract is an opacity of the lens of the eye or its capsule. The main complaint is gradual loss of vision. Other features include glare, especially when driving at night and monocular diplopia (double vision in one eye persisting after the other eye is covered). On examination, the red reflex can be absent with difficulty viewing the fundus.

Gradual and painless reduction in VA. On examination, VA will have declined and the red reflex will be reduced. Small cataracts will stand out as dark defects, whilst a large cataract may obliterate the red reflex.

If a cataract is suspected, the patient should be advised to have their eyes examined by an optometrist in order to assess their visual acuity and exclude other causes of visual impairment. Referral for surgery should be considered if a cataract impacts on a patient’s daily activities. Surgery may also be indicated if the patient has another eye condition, where cataract surgery would facilitate treatment or monitoring

About 1–3% of those who have cataract extractions will experience decreased vision due to cystoid macular oedema, usually from 2-4 months after surgery. Swelling of the macula causes a decrease or blurring of central vision. In most cases, cystoid macular oedema is treated with a non-steroidal anti-inflammatory medication.

The severe complication of endophthalmitis occurs earlier in the post-operative period and produces a red and painful eye.

Cataracts (CKS)