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Evaluation of Long-Term Corneal Morphology After Photorefractive Keratectomy by In Vivo Confocal Microscopy and Specular Microscopy; 20-Year Follow-Up

Bilgihan, Kamil M.D.; Yesilirmak, Nilufer M.D.; Altay, Yesim M.D.; Tefon, Atike B. M.D.; Ozdemir, Huseyin B. M.D.; Ozdogan, Sibel M.D.; Kocamaz, Mehmet F. M.D.; Gurelik, Gokhan M.D.

doi: 10.1097/ICL.0000000000000585

Purpose: To evaluate long-term corneal morphological changes after photorefractive keratectomy (PRK) using in vivo confocal microscopy (IVCM) and specular microscopy.

Methods: This comparative case–control study included 16 eyes of 8 patients who underwent PRK for mild to moderate myopia 20 years ago and 30 eyes of 15 sex- and age-matched healthy controls. Corneal epithelial cells, sub-basal nerves, keratocytes (anterior, midstromal, and posterior), and endothelial cells were evaluated in both groups 10 and 20 years after surgery. Long-term visual outcomes were also recorded.

Results: In vivo confocal microscopy examination revealed similar epithelial morphology, sub-basal nerve fiber morphology/density, mid/posterior stromal keratocyte density, and endothelial cell density between PRK patients and controls at their 10th and 20th year follow-up. Anterior stromal keratocyte density was lower at 10th year; however, it reached to control group value at 20th year follow-up. Extracellular matrix reflectivity was slightly higher, and there was a trace subepithelial corneal haze in PRK group (milder in 20th year than 10th year) compared with controls. At the 20th year, uncorrected distance visual acuity was 20/20 or more in 6 eyes (37.5%), 20/40 or more in 16 eyes (100%), and all eyes had corrected distance visual acuity of 20/20 or better (spherical equivalent −0.31±0.37 D).

Conclusions: Photorefractive keratectomy in low to moderate myopia seems to be safe and effective method in the long term with preserving corneal morphology (including anterior stromal keratocyte and sub-basal nerve fiber density) and refractive outcomes as shown in this study. In appropriate patients, this method can be considered confidently.

Department of Ophthalmology (K.B., N.Y., A.B.T., and G.G.), Gazi University Hospital, Ankara, Turkey; Department of Ophthalmology (N.Y.), Yildirim Beyazit University, Ataturk Training and Research Hospital, Ankara, Turkey; Department of Ophthalmology (Y.A. and M.F.K.), Ufuk University Hospital, Ankara, Turkey; Department of Ophthalmology (H.B.O.), Ulucanlar Training and Research Hospital, Ankara, Turkey; and Department of Ophthalmology (S.O.), Ankara Oncology Training and Research Hospital, Ankara, Turkey.

Address correspondence to Kamil Bilgihan, M.D., Gazi Universitesi Tip Fakultesi Hastanesi, Goz Hastaliklari Anabilim Dali, Besevler, Ankara 06500, Turkey; e-mail:

The author has no funding or conflicts of interest to disclose.

Presented at the 23rd ESCRS Meeting, 2005, Lisbon, Portugal, and at the TOA 51st National Congress, Antalya, Turkey.

Accepted December 30, 2018

© 2019 Contact Lens Association of Ophthalmologists, Inc.