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Long-Term Density Changes in Corneal Layers After Primary Pterygium Excision With Topical Mitomycin-C

Purpose: To evaluate the long-term change in average corneal densities at 18 months after primary pterygium excision with topical adjuvant mitomycin-C application, particularly the relationship between anterior and posterior corneal layer densities. Methods: Prospective observational case series. Patients were imaged with the Pentacam at 18 months after their surgery. Average corneal densities were the primary outcome and were compared with postoperative weeks 1, 4, and 12 data using paired t test. Results: In all, 31 eyes of 31 patients were recruited. Mean age at time of operation was 62.0 ± 9.4 years. Mean best-corrected logarithm of the minimal angle of resolution visual acuity at 18 months was 0.14. The mean total anterior, central, and posterior average corneal densities were 30.6, 25.9, and 20.5 respectively. Compared with postoperative week 1 data, the anterior layer was reduced by 12.7% (P = 0.0144); however, there was no significant change in the central and posterior layers (P = 0.5353 and 0.0858, respectively). Subgroup analyses did not support the use of a 10- to 12-mm annulus as opposed to total-diameter data, and density reduction effect at 18 months from week 12 and week 1 seemed to be stronger in males (P = 0.0074 and 0.0042, respectively). Conclusions: Anterior corneal scars continued to diminish in density with time. Previous finding of a significant increase in posterior layer density at postoperative week 12 is likely not a result of optical phenomenon caused by a less dense anterior layer. Sex difference in terms of scar remodeling may be present.