CATARACTA NIGRA: A CASE REPORT

Cataracts are partial or total opacification of the crystalline lens. In adults, cataracts are acquired, the most common form being age-related cataracts. According to the World Health Organization (WHO), cataracts are the leading cause of curable blindness worldwide, with 35% of blind people affected by cataracts. Cataract nigra is a very rare form of cataract in elderly subjects.

Department of Ophthalmology B, Rabat Specialty Hospital, CHU ibn Sina, Mohammed V Souissi University Rabat

We report the case of a 90-year-old patient, with no notable pathological history (no previous ocular disease or ocular trauma), who consulted for a progressive, profound drop in visual acuity in both eyes. Ophthalmological examination after pupillary dilation revealed a slightly dull bluish-grey crystalline surface , and direct focal illumination revealed a dark brown crystalline lens, with the deep layers not visible in the right eye, and a total cataract in the left eye, with the fundus inaccessible.

The patient underwent extracapsular cataract surgery, which revealed the typical appearance of a cataract nigra, a rare form of cataract in the elderly.

Black cataract is a rare form of cataract in elderly patients, with a fairly typical clinical appearance, but its exact prevalence has not yet been published. One hypothesis suggests that lens proteins become insoluble in water and aggregate so that the lens nucleus becomes so hard, and blackened, and also suggests that aging is an important factor in the accumulation of these proteins that leads to the formation of black cataract. The only curative treatment is surgery.

The functional impact of cataracts is assessed clinically. The common symptom is reduced visual acuity, but each has its own associated clinical signs. Knowledge of the semiology and clinical forms of cataracts enables the indication for surgery to be established in accordance with good ophthalmic practice.