Study subjects were part of a larger longitudinal cohort of patients enrolled as glaucoma suspects at their initial visit based on a detailed medical and ocular history and a comprehensive eye examination as previously described.
6 Inclusion criteria were: refractive errors within −5 to +3 diopters, best corrected visual acuity (BCVA) better than or equal to 20/20 (Snellen), normal standard automated perimetry (SAP) according to the Ocular Hypertension Treatment Study (OHTS) criteria
15 (reliability <15% on all indices, normality >5% on all global indices in two consecutive sessions 6 months apart), and glaucomatous optic disc appearance (vertical cup/disc ratio [C/D] ≥0.5, C/D asymmetry ≥0.2, localized thinning of the disc, splinter hemorrhage) or increased IOP (>21 mm Hg). To qualify for the present retrospective study, patients had to be monitored with PERG twice a year over a follow-up period longer than 6 years. We identified in our longitudinal cohort all glaucoma suspects (
n = 15, 28 eyes) that received treatment at some point during the follow-up and had a sufficient number of observations before and after the break point. From the same cohort, a control group of untreated patients (
n = 17, 31 eyes) was randomly selected with similar age range and follow-up time as the study group. Initiation of therapy in the study group was weighted in concert with the individual patients taking into account a constellation of risk factors including optic disc cupping, corneal thickness, family history, race, life expectancy, and psychosocial issues.
16 The 5-year risk of developing primary open-angle glaucoma, retrospectively calculated using the OHTS-European Glaucoma Prevention Study (EGPS) point system available online (
http://ohts.wustl.edu/risk/calculator.html), was higher in the treated group compared with the untreated (9.03 ± 2.36 vs. 7.83 ± 1.71;
P = 0.028). The decision to treat was not based on the OHTS-EGPS calculated risk, as the predictive models are valid for patients that meet the inclusion criteria of OHTS, and could not be generalized to our glaucoma suspect population.
16 The decision to treat was also not based on PERG measurements. Treatment consisted of either prostaglandin analogs (22/28 eyes; 79%) or β-blockers (6/28 eyes; 21%), which are known not to cause changes in pupil size (American Academy of Ophthalmology Preferred Practice Pattern, Glaucoma Panel, Hoskins Center for Quality Eye Care;
http://www.aao/ppp).