Abstract
Abstract: :
Purpose:To determine the relationship of central corneal thickness and visual field loss between fellow eyes in patients with primary open angle glaucoma. Methods: A retrospective chart review was done on all patients with open angle glaucoma seen at the Indianapolis VA Hospital during 6 consecutive months. The patients’ age, sex, type of glaucoma, central corneal thickness (CCT), visual acuity (VA), C:D ratio, Mean deviation (MD), and pattern standard deviation (PSD) were recorded. All patients were required to have had CCT measurements and HVF testing done within one month of each other. Patients were excluded with vision worse than 20/40, corneal dystrophy or disease, retinal pathology or macular disease, and prior glaucoma or other surgery that would affect visual fields. Results: Sixty–nine patients were identified who met both the inclusion and exclusion criteria. For all 69 subjects, the Spearman correlation coefficient between the differences in CCT versus differences in MD was 0.31 (P=0.009). In a subset of 22 subjects with CCT difference of 10 or more microns, the correlation was 0.64 (P=0.001). In a direct comparison of the CCT of fellow eyes, the eye with the worse MD had a mean CCT of 547.7 microns while the fellow eye had a CCT of 549.8 microns (p=0.09, paired t test) for all 69 subjects and 551.4 vs. 556.3 (p=0.20, paired t test) for the 22 subjects with 10 or greater micron CCT different between the two eyes. In the eye with the thinner CCT, the MD (–5.8 vs. –4.2, p=0.007, paired t test) and the PSD (4.6 vs. 3.6, p=0.004, paired t test) was significantly worse than in the eye with the thicker CCT for all 69 cases. Similarly, for the 22 patients with a CCT difference of 10 microns or greater between the fellow eyes, the eye with the thinner CCT had a worse MD (–4.7 vs. –2.3, p=0.049, paired t test) and worse PSD (3.8 vs. 2.4, p=0.058, paired t test). Conclusions: In a patient with POAG, disease severity based on visual field loss is significantly worse in the eye with the thinner cornea. Several studies have concluded that central corneal thickness is a risk factor for POAG[1]. Recently, disease progression in patients with POAG was found to be associated with a thinner CCT[2]. Our results confirm these findings within the same patient and demonstrate the importance of CCT in the management of glaucoma patients. [1] Gordon MO, et al. The Ocular Hypertension Treatment Study: baseline factors that predict the onset of primary open–angle glaucoma. Arch Ophthalmol 2002;120:714–720. [2] Kim JW, et al. Central Corneal Pachymetry and Visual Field Progression in Patients with Open–Angle Glaucoma. Ophthalmology 2004;111:2126–2132.
Keywords: clinical (human) or epidemiologic studies: risk factor assessment • perimetry