Abstract
Purpose: :
: Hypotony is a frequent complication following glaucoma surgery that often results in visual loss. We hypothesized that patients with increased central corneal thickness (CCT) may have an overestimation of measured Goldmann applanation IOP and predisposition to hypotony–related complications (HRC). The purpose of this study was to examine the relationship between CCT and post–operative HRC.
Methods: :
A retrospective case–control analysis was performed on patients examined at Bascom Palmer Eye Institute who had glaucoma filtering surgery with resulting hypotony. Hypotony was defined as IOP < 7 mmHg on two consecutive postoperative visits. Data was abstracted from the medical records including age, ethnicity, gender, visual acuity, pre and post–operative IOP, refractive error, and type of glaucoma surgery. CCT was obtained using an average of three readings per eye. Exclusion criteria consisted of visual acuity < 20/100, corneal pathology, or prior corneal or vitreo–retinal surgery. HRC consisted of choroidal effusion or hypotony maculopathy.
Results: :
Fifty eyes of 47 patients (mean age 71.6 ± 10, range 42–87) were enrolled. Twenty one cases of HRC and 29 controls were identified. There was no difference (P >0.05) in age, gender, race, refractive error, or use of antifibrotic agents between cases and controls. Mean post–operative IOP readings were significantly (p=0.03) lower in eyes with HRC (4.0 + 1.8 mmHg) than controls (5.0 + 1.3 mmHg). Mean CCT was similar (p=0.5) in cases (517 + 35um) and controls (523 + 35um).
Conclusions: :
These data suggest that CCT does not represent a risk factor for HRC after glaucoma surgery and Goldmann applanation tonometry readings are not overestimated by thicker CCT in such eyes.
Keywords: intraocular pressure • macula/fovea • clinical (human) or epidemiologic studies: risk factor assessment