Laser Scanning Confocal Ophthalmoscopy and Polarimetry of Human Immunodeficiency Virus Patients Without Retinopathy, Under Antiretroviral Therapy

Abstract

Confocal laser scanning ophthalmoscopy (HRT; Heidelberg retinal tomograph II) and scanning laser polarimetry (GDx-variable corneal compensator [VCC]) were used to investigate whether early indicators of retinal nerve fiber layer (RNFL) thickness loss could be observed in patients infected with the human immunodeficiency virus (HIV) that had no associated retinopathy or optic neuropathy and were concomitantly receiving antiretroviral medications. HRT and GDx-VCC parameters obtained from a group of 13 HIV-positive subjects (n=26 eyes) on antiretroviral therapy examined with HRT, with a subgroup of six subjects (n=12 eyes) examined with both HRT and GDx-VCC, were compared with those of a matched HIV-negative control cohort (13 subjects, n=26 eyes) examined with HRT, with a subgroup of five subjects (n=10 eyes) examined with both HRT and GDx-VCC. We employed generalized estimating equations for statistical analysis. Reduced mean values for the HRT height variation contour (p<0.045) and HRT mean RNFL thickness (p<0.023) were observed in HIV-positive subjects controlling for age, sex, and race. A significantly reduced mean value corresponding to the GDx-VCC superior maximum (p<0.014) and inferior maximum (p<0.016) were also observed for the HIV-positive cohort analyzed controlling for age, sex, and race. HRT and GDx-VCC indicators of RNFL thickness appear to be significantly reduced in HIV-positive subjects without retinopathy or optic nerve disease using antiretroviral medication, suggesting RNFL loss occurs in this population of HIV-positive patients. The lack of correlation between CD4 counts, viral load, number of antiretroviral medications used, or years from diagnosis of HIV and RNFL thinning, suggests that possibly other factors associated with HIV infection may contribute to the apparent RNFL thickness loss.