Unexplained vision loss in AIDS patients calls for fluorescein angiography

Ischemic maculopathy may be the culprit in patients with HIV infection who experience unexplained loss of vision, researchers report in the November issue of the American Journal of Ophthalmology. But fluorescein angiography is needed to confirm this, they add.

Dr Emmett T Cunningham Jr, of the University of California at San Francisco and a multicentre team reviewed the cases of five AIDS patients with ischemic maculopathy in an attempt to gain a greater understanding of this “uncommon disorder.” There are “few” cases of HIV-related symptomatic ischemic maculopathy in the medical literature, they write.

In all five cases, fluorescein angiography facilitated the diagnosis of ischemic maculopathy following complaints of vision loss. Onset was usually abrupt with “opacification of the superficial retina, resulting in a cherry red spot, and intraretinal haemorrhages near the fovea” clearly present in most, but not all cases. Because these changes may be absent or transient in some patients, the researchers recommend that fluorescein angiography be performed in all HIV-infected patients with unexplained vision loss.

Four of the five patients had bilateral macular disease and visual acuity at presentation varied widely, ranging from “20/20 to counting fingers,” Dr Cunningham’s team reports.

The pathogenesis of ischemic maculopathy remains unknown, although the evidence in this case series points to occult herpetic infection as a contributing factor, they write. Seven affected eyes had cytomegalovirus (CMV) retinitis and all patients were taking anti-CMV agents when they developed visual problems.

“HIV infection itself is capable of reducing vision by damaging the fine capillaries of… the macula,” Dr Cunningham said. “This cause of vision loss might be easily missed if not looked for specifically with fluorescein angiography.”

Comment

Ischemic maculopathy is caused by blockage of tiny blood vessels in the macula and has been reported as leading to vision loss in HIV-infected patients in the UK and only occurs in people who have had CMV retinitis. It may well be a late finding after cystoid macula oedema associated with severe immune recovery uveitis that has not been treated aggressively when first seen or that is unresponsive to treatment.

Flourescein is an inexpensive, non-toxic, highly fluorescent compound. It absorbs blue light and emits yellow-green light, and therefore only relatively simple modification of existing fundas cameras is necessary to perform angiography.

Fundus photography in rapid sequence after intravenous injection of fluorescent dye provides information on the flow characteristics in the blood vessels, and fine details of the retina and choroids that may not be appreciated by other means. Normal retinal vessels are impermeable to the dye. This allows a clear picture of the retinal vessels and assessment of their functional integrity, since leakage from any retinal vessel is abnormal.

The advice from Dr Cunningham, one of the most experienced doctors in this field, should be adopted for all patients in this situation.