Abstract
Purpose :
To assess and compare both eyes monochromatic-wave aberrations, of subjects with unilateral primary pterygium.
Methods :
A prospective, descriptive case series evaluated patients with unilateral primary pterygium. Thirty patients with unilateral primary pterygium underwent corneal aberration study with the Schwind Sirius. Inclusion criteria were patients with unilateral primary pterygium. Patients with ocular pathologies, previous ocular surgery, abnormal findings not related to the pterygium, any abnormal change in the normal fellow eye were excluded. The Zernike coefficient were determined up to the fifth order, and root mean square (RMS) of sphere, cylinder and high order corneal aberrations. All quantitative variables were compared using a paired t test and a p value of less than 0.05 was considered statistically significant. Two-way analysis of variance was used for comparing between eyes with pterygium and the normal fellow eye, also for comparison between both pterygium groups. All data was processed and analyzed using SPSS version 17 (IBM Corp., NY).
Results :
Sixty eyes were included of thirty, 11 men (36.7%) and 18 women (63.3%) with a mean age of 52.2 years ± 11.67 years. The mean cylinder value was -1.3 D in pterygium group and - 0.48 D in non-pterygium group, P <0.05. The mean Kmax 47.30 ± 7.81 D in pterygium group and 44.36 ± 1.29 D in non-pterygium group P<0.05. The major aberrations found in eyes without pterygium was astigmatism mean 4.33 μm, trefoil mean 2.25 μm, cuadrifoil mean 1.28 μm, coma mean 0.96 μm, and in affected eyes astigmatism mean 2.62 μm, and trefoil mean 1.26 μm. When we compared both groups all aberrations was statistically different, least spherical aberration p<0.05; and all the aberrations were bigger in eyes with pterygiums >2mm.
Conclusions :
Pterygium leads to deterioration of visual performance by causing a significant increase in corneal aberrations. The size of pterygium is a factor that determines the grade of aberration. This study demonstrated that even incipient pterygium, <2 mm can cause corneal abnormalities. Further studies are necessary to evaluate changes in this other aberrations posterior to surgical treatment.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.