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Kirsten Midgley, Jenny Ha, Michael Korchak, Jayson Koppinger, Sandra Lora Cremers, Jesus Alberto Martinez; Largest Report of the Effect of Primary Pterygium on Corneal Endothelial Cell Density. Invest. Ophthalmol. Vis. Sci. 2016;57(12):5262.
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© ARVO (1962-2015); The Authors (2016-present)
A recent study published in Cornea (2014) reported that primary pterygium is associated with decreased corneal endothelial cell density (ECD), which could be related to its severity, measured by astigmatism (Astig). We present the largest and first US study to compare ECD in patients with pterygium and attempt to reproduce the previous study. We hypothesized that there would be no significant difference in ECD between pterygium and fellow eyes and no association between astigmatism and ECD.
In this retrospective study, 219 eyes of 152 patients with primary pterygium and no previous ocular surgery or trauma were examined. Preoperative ECD (Cellchek, Konan, USA), % of hexagonal endothelial cells (HEX), and Astig (Pentacam, Oculus Inc, USA), were obtained. In a subset of 83 patients with unilateral pterygium, the endothelial cell data were compared between the pterygium and the unaffected fellow eyes. Pearson correlations assessed the relationship between Astig, ECD and HEX; these analyses were repeated controlling for age. Paired t-tests were used to investigate differences in ECD and HEX in pterygium vs. control eyes. These analyses were repeated after excluding patients with fellow eyes’ Astig >2 D and an ECD difference ((healthy ECD - pterygium ECD)/healthy ECD) greater than -10%, as did Cornea paper. P<0.05 was considered statistically significant.
The average ECD and HEX were 2715.59±197.21 and 43.57±4.84, respectively. ECD (r=-0.067, p=0.321) and HEX (r=-0.019, p=0.784) were not correlated with Astig. Controlling for age (mean 46.1 ± 11.4) did not affect these correlation results (ECD r=-0.053, p=0.434; HEX r=-0.17, p=0.798). A subanalysis of 83 patients with unilateral pterygium revealed no significant difference between pterygium and fellow eyes (ECD p=0.871, HEX p=0.594). After applying previously published exclusion criteria, the remaining 77 eyes with primary unilateral pterygium showed no association between the degree of Astig difference (mean 0.40 ± 1.34) and percent of ECD decrease (0.00 ± 0.05%; r=-0.008, p=0.945).
We present the largest study of ECD eyes with primary pterygium, and also attempted to reproduce a previously published article. When used as a measure of pterygium severity, astigmatism was not correlated with ECD. Furthermore, in patients with unilateral pterygium, there was no association between the difference in astigmatism and ECD decreases.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.
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