Abstract
Purpose: :
We sought to identify the intraocular pressure (IOP) parameter that best correlated with corneal hysteresis (CH) in a large database of patients with and without open-angle glaucoma (OAG).
Methods: :
In this retrospective study, we included patients with at least 10 office visits where Ocular Response Analyzer (ORA; Reichert Corp., Buffalo, NY) measurement was performed. Each ORA measurement was performed on a different day. Mean, peak, and standard deviation (SD) of Goldmann-correlated IOP were recorded, and Pearson correlation and linear regression were used to model the associations between IOP parameters and CH.
Results: :
We included records from 957 normal and 291 treated OAG patients. The mean duration of follow-up for normal and OAG patients was 3.0 ± 1.4 and 4.4 ± 1.1 years and the mean number of ORA measurements was 17.9 ± 7.3 and 23.3 ± 10.1, respectively. In both normal and OAG patients, SD of IOP was the IOP parameter that correlated most strongly with both baseline (Normal: r=-0.28; OAG: r=-0.30) and most recent follow-up CH (Normal: r=-0.23; OAG: r=-0.36). Age (p<0.001), but not duration of follow-up (p≥0.23), was significantly associated with CH for normal and OAG patients. Multivariable analysis demonstrated a statistically significant inverse relationship between CH and SD of IOP after adjusting for age among both normal and OAG patients (p<0.001). The results were similar whether baseline or most recent follow-up CH was the independent variable and results were unchanged when censoring the first two office visits among OAG patients to account for initiation of IOP lowering therapy.
Conclusions: :
In both normal and OAG patients, SD of IOP was more strongly correlated with CH than mean and peak IOP, and a higher SD of IOP was associated with lower CH independent of age. Lower CH may be measured in patients with greater IOP fluctuation.
Keywords: intraocular pressure • clinical (human) or epidemiologic studies: biostatistics/epidemiology methodology