Cone Location-Dependent Outcomes After Combined Topography-Guided Photorefractive Keratectomy and Collagen Cross-linking

Rohit Shetty, Rudy M. M. A. Nuijts, Maneck Nicholson, Koushik Sargod, Chaitra Jayadev, Himabindu Veluri, Abhijit Sinha Roy*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

PURPOSE: To evaluate the effect of keratoconus cone location on the change in refractive outcomes, corneal aberrations, and biomechanics after combined topography-guided photorefractive keratectomy (PRK) and collagen cross-linking (CXL). DESIGN: Prospective, comparative case series. METHODS: Topography-guided PRK was performed followed by accelerated CXL using riboflavin A and enhanced-intensity (30 mW/cm(2)) ultraviolet light. Outcome parameters including uncorrected distance visual acuity (UDVA) and best-corrected distance visual acuity (BDVA), corneal tomography and biomechanics (corneal hysteresis [CH] and corneal resistance factor [CRF], and corneal wavefront aberrations were assessed before and a year after the procedure. Eyes were subdivided into 2 groups preoperatively for statistical analysis: Group 1, cone located within the central 2-mm zone; and Group 2, cone located outside the central 2-mm zone. RESULTS: UDVA, BDVA, sphere, cylinder, and simulated keratometry improved after treatment in both groups (P <.05). However, BDVA improved more in Group 1 than in Group 2 (P = .04) and the other variables were not affected by cone location. A few corneal wavefront Zernike aberrations changed after treatment (P <.05) but none were affected by cone location (P > .05). CH and CRF increased after treatment in both groups (P > .05). Interestingly, the increases in CH and CRF were greater in Group 2 than in Group 1 (P > .05). CONCLUSIONS: Cone location appeared to impact only visual acuity and biomechanics after the combined procedure. The greater increase in CH and CRF in Group 2 may indicate differences in the ablation profile and variability in CXL outcomes and requires further study.
Original languageEnglish
Pages (from-to)419-425
JournalAmerican Journal of Ophthalmology
Volume159
Issue number3
DOIs
Publication statusPublished - Mar 2015

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