Optical coherence tomography gauges HIV retinal damage
Updated: 2005-03-31 (Reuters Health)
By David Douglas
NEW YORK (Reuters Health) – Optical coherence tomography (OCT) is useful in assessing retinal nerve fiber layer (RNFL) thickness in HIV patients, who can develop visual problems in the absence of cytomegalovirus (CMV) retinitis.
By using OCT, senior investigator Dr. William R. Freeman told Reuters Health, “one can objectively measure the damage to the retina which appears to result in these vision losses in HIV patients without infections in the retina.”
Dr. Freeman pointed out that such visual difficulties “can be objectively documented by showing problems with color vision, the ability to see subtle contrast changes and defects in the peripheral vision.” However, “performing these tests is time consuming and difficult.”
To determine whether OCT might be useful in this connection, Dr. Freeman of the Shiley Eye Center of the University of California, San Diego in La Jolla and colleagues conducted a case-control study, using third-generation OCT to measure RNFL. This new approach provides higher resolution than was previously available.
The study involved 36 eyes of 18 HIV patients without CMV retinitis and CD4 counts above 100, 38 eyes in 25 similar HIV patients but with CD4 counts below 100, and 39 eyes in 22 HIV-negative controls.
HIV patients in the lower CD4 count group had significantly thinner overall RNFL than did the patients with higher counts and the controls. The difference was most prominent in temporal, superior and inferior retinal areas.
Thus Dr. Freeman concluded, this “structural imaging test of the retina” has shown that “there was retinal damage which could be the cause of these functional vision losses.”
Am J Ophthalmol 2005;139:295-301.
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