| KERATOCONUS UPDATE |
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| Year : 2022 | Volume
: 36
| Issue : 1 | Page : 25-35 |
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Applications of epithelial thickness mapping in corneal refractive surgery
Dan Z Reinstein1, Timothy J Archer2, Ryan S Vida3
1 London Vision Clinic, London, United Kingdom; Department of Ophthalmology, Columbia University Medical Center, New York, USA; Department of Ophthalmology, Sorbonne Université, Paris, France; School of Biomedical Sciences, Ulster University, Coleraine, United Kingdom
2 London Vision Clinic, London; School of Biomedical Sciences, Ulster University, Coleraine, United Kingdom
3 London Vision Clinic, London, United Kingdom
Correspondence Address:
Dr. Dan Z Reinstein
London Vision Clinic, 138 Harley Street, London W1G 7 LA
 Source of Support: None, Conflict of Interest: None
DOI: 10.4103/sjopt.sjopt_227_21
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In this review, we discuss the applications of epithelial thickness mapping in corneal refractive surgery. The review describes that the epithelial thickness profile is nonuniform in the normal eye, being thinner superiorly than inferiorly and thinner temporally than nasally. It is postulated that this is due to the eyelid forces and blinking action on the superior cornea. Changes in the epithelial thickness profile have been found to be highly predictable, responding to compensate for changes in the stromal curvature gradient, using the eyelid as an outer template. This leads to characteristic changes in the epithelial thickness profile that can be used for early screening in keratoconus, postoperative monitoring for early signs of corneal ectasia, and for determining whether further steepening can be performed without the risk of apical syndrome following primary hyperopic treatment. Compensatory epithelial thickness changes are also a critical part of diagnosis in irregular astigmatism as these partially mask the stromal surface irregularities. The epithelial thickness map can then be used to plan a trans-epithelial photorefractive keratectomy treatment for cases of irregularly irregular astigmatism.
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