Correlation of Visual Function and Structural Measurements in Patients With HIV and Normal Controls

Abstract

Purpose: : HIV patients without infectious retinitis have been shown to have vision loss. This vision loss can be measured by contrast and color vision testing, visual fields and electrophysiology. We have recently found that a structural basis of this can be demonstrated by evaluation of nerve fiber and optic disc morphology. We wished to evaluate the relationship between morphological changes in retinal nerve fiber layer and functional measures such as vision, quality of life as well as CD4 nadir in HIV patients without retinitis.

Methods: : To evaluate the structural basis of vision loss in HIV patients without retinitis 140 eyes of 75 patients were evaluated at the UCSD Jacobs Retina Center. All were in HIV positive patients without current or past infectious retinitis. We further sub-divided our group of patients with HIV into those who never reported CD4 count of below 100 (HIV high) and those who did present at one point with a CD4 nadir of below 100 (HIV low). Clinical examination followed standard protocols. In addition, we recorded functional measures such as vision quality of life (VFQ-25), ETDRS visual acuity, contrast sensitivity testing, Farnswell-Munsell 100 Hue color testing, and multifocal ERG. Structural measures included peripapillary OCT imaging (StratusOCT), and RNFL polarimetry (LDT GDx). These measurements were performed on each patient/eye in a prospective study. A group of normal volunteers who are HIV negative was our control group (normal).

Results: : Polarimetry results (NFI, Symmetry, Inferior Ratio, Superior Nasal, Inferior Maximum) and OCT results (Inferior Average, Inferior Maximum, Maximum-Minimum Difference, Smax to Imax ratio) were all significantly different between our HIV high, HIV low and normal groups. There was a significant correlation between quality of life score and structural measurements (VFQ-25 score and inferior average in OCT and polarimetry).

Conclusions: : Structural changes seen in the retina of HIV patients without retinitis are present and correlated with visual function loss. Further longitudinal studies may demonstrate a predictive relationship between structural changes and functional changes. Structural changes may be a useful measure of lifetime HIV burden. There is a significant correlation between structural changes and function including quality of life. Further data on a statistical model analyzing several measures of structure and function in HIV patients without retinitis will be presented.

Keywords: AIDS/HIV • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • imaging/image analysis: clinical