Abstract
Introduction:
Pterygium is a centripetal proliferation of fibrovascular tissue, which proceeds from the bulbar conjunctiva towards the center of the cornea. Excision of the pterygium may cause visual acuity improvement and surgical excision aims to achieve a topographically regular ocular surface. The improvement of the visual acuity results from the alteration of the refractive corneal power, that is measured in the topography as alteration of the topographic astigmatism. The objective of this study was to evaluate the variation of the final topographic astigmatism after the pterygium excision surgery.
Methods:
A prospective study was carried out to follow up patients after pterygium excision surgery with corneal topography before and 1 month after the surgery. The population was of the non-probabilistic type of volunteers, with n of 74 eyes. Sampling was for convenience and participation was offered to patients from the ophthalmology residence outpatient service who underwent pterygium excision between July and December 2015.
Results:
A total of 74 surgeries were performed in the period and 44 were included in the statistical analysis. Mean values of topographic astigmatism (CYL) showed a statistically significant reduction from 2.715D to 1.448D (p = 0.0037). The change in the more curved meridian (Ks) showed no significant change from 45.60D to 45.32D (p = 0.1050), while the meridian plane at 90º Ks (Kf) showed a significant increase from 42.86D to 43,87D (p = 0.0052). Isolated analysis of the groups showed that only the group with grade 3 pterygia suffered a significant alteration of CYL from 7,12D to 1,82D (p = 0,0002).
Conclusion:
The surgery resulted in a significant reduction of topographic astigmatism only in patients with grade 3 pterygium, due to the reduction of the flattening caused by the pterygium.
Keywords:
Pterygium; Cornea; Conjunctiva; Ophthalmologic surgical procedures; Corneal topography
