Abstract
Purpose: :
We have previously analyzed optic nerve morphology to evaluate decreased vision in human immunodeficiency virus (HIV) patients using the HRT. We now expand this study further including refractive errors in the regression analysis. We wish to determine if retinal nerve fiber layer (NFL) loss secondary to HIV disease in patients with a history of high and low CD4 groups translates to change in optic disc morphology using the Heidelberg Retina Tomograph (HRT).
Methods: :
The study included 181 eyes of 92 patients (72 men, 20 women) who were divided into three groups. Group one consisted of 40 eyes of 20 HIV-negative patients who served as control subjects. Group 2 consisted of 80 eyes of 41 HIV-positive patients who never had a CD4 count less than 100 (1.0 x 109/L). Group 3 consisted of 44 eyes of 26 HIV-positive patients with a history of CD4 counts below 100 lasting at least 6 months. Concurrent or healed cytomegalovirus (CMV) retinitis in an eye was an exclusion criterion; however, fellow eyes of CMV retinitis were included. These three groups had their optic disc analyzed using the HRT3. Measurements of the mean retinal NFL thickness and cross-sectional area of the optic disc were obtained using the HRT. Refractive error was included in the regression analysis of the data.
Results: :
HRT3 measurement of mean retinal NFL thickness showed a statistically significant difference (p value < 0.05) between eyes of HIV-negative and HIV-positive subjects. HIV-positive eyes with a history of low CD4 count had more loss of retinal NFL than high CD4 eyes. Similar differences among all three groups were found measuring retinal NFL cross sectional area. There was not a major difference in the measure of optic nerve head cup across the three groups.
Conclusions: :
HRT3 uses a novel algorithm in imaging optic disc and retinal NFL. This study confirms retinal NFL loss as demonstrated with other imaging instruments. The optic disc parameters, however, are not changed, making HIV-associated retinal NFL loss different from glaucomatous damage.
Keywords: retina • AIDS/HIV • nerve fiber layer