Vision loss affecting one in ten Ugandan people with HIV

The lack of routine eye care was the likely cause of the unrecognised but significant and preventable vision loss and eye disease among 11% of HIV-infected adults attending an HIV treatment site in Kampala, Uganda, report Juliet Otiti-Sengeri and colleagues in the Journal of Acquired Immune Deficiency Syndromes.

While roll-out of antiretroviral therapy will continue and so help reduce HIV-related eye problems, two issues will need to be addressed by HIV treatment programmes note the authors. HIV-infected individuals will continue to present with advanced disease and with opportunistic eye infections that require specialised treatment. In addition, antiretroviral therapy can cause immune recovery inflammatory syndromes of the eye, which also need to be managed.

Before antiretroviral therapy was available an estimated 50-75% of HIV-infected individuals in North America and Europe developed vision-related illnesses with cytomegalovirus (CMV) retinitis the primary cause of vision loss.

Prevalence of diseases of the eye in sub-Saharan Africa is estimated to be between 30 and 45%. Eye tumours and opportunistic infections causing vision loss and illnesses of the eye in resource-poor settings are often due to tuberculosis, Cryptococcus and toxoplasmosis, unlike resource-rich settings.

In resource-poor settings the more common and treatable causes of vision loss are also associated with opportunistic eye infections due to herpes viruses, in particular cytomegalovirus and to a lesser degree herpes simplex virus and varicella zoster virus.

Since the widespread introduction of antiretroviral therapy in Uganda in 2004 approximately 120,000 are now getting ART out of an estimated 1 million people living with HIV. Yet, the authors note there is little known about the extent of vision loss among people infected with HIV.

From July 2003 until August 2004 the authors screened 1,212 HIV-infected adults 18 years of age or older attending an outpatient infectious disease clinic at Mulago Hospital in Uganda to determine the extent of vision loss as well as to describe HIV-related eye diseases.

The clinic is an HIV research, training and treatment site and Mulago Hospital is Uganda’s national referral hospital and a university teaching hospital.

Those with vision loss of 6/9 or less in one or both eyes had a comprehensive diagnosis and evaluation of the eyes. 6/6 (or 20/20 in the United States) is the universal standard for ‘perfect’ vision and is a measure of how well a person sees and is referred to as visual acuity.

136 (11.2 %) patients (CI: 95% 9.49-13.13) had a vision loss of 6/9 or worse in at least one eye of which 66 (49%) had reduced vision in both eyes.

Eye diseases associated with legal blindness (6/60 or worse) were mostly related to opportunistic infections. Of the 136 patients 16 (11.8%) had cataracts, 20 (14.7%) had optic nerve disease, 35 (24.3%) had refractive errors (failure of the eye to focus causing blurred vision) and 44(32.3%) had uveitis (the third leading cause of blindness in the developing world: inflammation or swelling of the middle layer of the eye structure).

Opportunistic infections primarily associated with vision loss with the potential to cause blindness, note the authors, included CMV retinitis, toxoplasmosis of the eye, deterioration of the optic nerve as a result of cryptococcal meningitis and ethambutol optic nerve toxicity.

They also stress that ART presents an additional risk factor for loss of vision with CMV retinitis in the form of immune recovery uveitis.

Ethambutol toxicity is a known cause of visual loss for patients on TB therapy. The authors suggest if patients are monitored for loss of vision and of colour whilst on therapy blindness is preventable.

The authors highlight that before the availability of ART vision loss because of cryptococcal meningitis or TB treatment in sub-Saharan Africa was rarely seen in HIV-infected individuals. This may be a reflection of improved treatment and so survival.

The authors note factors that may have contributed to an underestimation of the prevalence of vision loss and include: patients with altered mental states, a common symptom of cryptoccocal meningitis, were excluded from the study; the high rate of CMV retinitis and subsequent short survival in sub-Saharan Africa – people are too ill to present for care; and those with eye disease but as yet undeveloped vision loss would also have been missed.

The authors note that a minority (26%) of those with impaired vision mentioned the fact during the screening process. While 40% were aware of problems but did not mention it to the physician, 34% only realised they had problems when tested.

The lack of specialised eye care, assessment and awareness about eye disease in HIV treatment sites, they stress, probably plays a part in adding to cases of preventable blindness.

People will continue presenting at a late stage of HIV infection putting them at increased risk of developing vision problems. The authors note that most treatable visual problems develop in people with a CD4 count under 200/mm³.

While they acknowledge the difficulties of identifying patients with eye disorders at a treatable stage the authors suggest simple steps to take. For example, medical assistants can determine visual acuity by asking questions about visual symptoms – floating spots, flashes, and visual loss.

Inpatients and those in hospice care can be examined by binocular indirect ophthalmoscopy (a simple hands-free device worn on the head that allows the doctor to examine a patient’s eyes) would, they suggest, result in identifying large numbers of potentially treatable cases.

They suggest “Research on cost-effective methods of identifying patients who are not under care is needed.” and conclude that “The problem of HIV-related blindness is extensive and deserves more attention as HIV care scales up worldwide.”