Does the Central Corneal Thickness (CCT) Play a Role in the Low Intra–Ocular Pressure (IOP) Found in HIV Infected Patients?

Abstract

Purpose: : To investigate the relationship between the HIV associated hypotony and CCT.

Methods: : We conducted a retrospective chart review of HIV+ patients. The control group consisted of glaucoma suspects who were not known to be HIV+. Both groups were matched for age. CCT, Cup to Disc ratio, IOP, and CD4/viral load were analyzed to determine any statistically significant correlation among HIV+ patients and controls.

Results: : 62 eyes from HIV+ patients and 82 Control eyes were studied. The two groups were matched for age and were compared using t–test for equal variance. The result showed that there are no significant differences in the ages of the control group and the HIV group (p = 0.521) assuring the same population. The following significance results were obtained: HIV group: 1. CCT is negatively correlated to Cup Disc (r = –0.364, p = 0.003). 2. CD4 is negatively correlated with VL (r = –0.329, p = 0.008). 3. CD4 is negatively correlated with Cup Disc (r = –0.229, p = 0.072). 4. VL is positively correlated with IOP (r = 0.284, p = 0.025). 5. Cup Disc is negatively correlated with IOP (r = –0.222, p =0.0825). This result was not found in the Control group. Control group: 1. CCT is negatively correlated with Cup Disc (r = –0.219, p = 0.047). This is consistent with the result found in the HIV group although the test was more significant in the HIV group. 2. CCT is negatively correlated with Age (r = –0.265, p = 0.0159). This result was not found in the HIV group. Therefore, there was no association between Age and CCT in the HIV group. Additional tests were done to compare the CCT and IOP of HIV patients against the Control group. The mean CCT in the Control group was 544.53 and that of the HIV group was 542.93. The mean IOP in the Control group was 15.47561 and that of the HIV group was 14.77419. The results show that there are no statistically significant differences in either case.

Conclusions: : These analyses reveal no statistically significant difference between the CCT and IOP of HIV patients compared to the controls with similar optic neuropathy. Patients with lower CD4 and higher viral load had increased Cup Disc ratio. It is noted that some of the control subjects were glaucoma suspects who were under treatment to lower their IOP. This may have skewed the IOP to the lower level in that group. Finally, the HIV associated hypotony does not appear to be an artifact of the CCT in the study population. A longitudinal study of HIV patients may help to further answer questions about the associated optic neuropathy, hypotony and extent of disease.

Keywords: AIDS/HIV • intraocular pressure • cornea: clinical science