Corneal morphology and visual outcomes in LASIK patients after orthokeratology: A pilot study

Analysis of Treatment Discontinuation in Orthokeratology: Studying Efficacy, Safety, and Patient Adherence Over Six Months

PURPOSE

This study aimed to evaluate the efficacy, safety, and participant compliance of orthokeratology treatment for the correction of myopic refractive errors over a six-month prospective study and to define the potential reasons for early treatment discontinuation.

METHODS

A total of 32 participants with low-to-moderate myopia were fitted with the spherical model of corneal refractive therapy (CRT) orthokeratology lenses (Paragon Vision Sciences) and followed over six months, with specific attention to alterations in refractive error, corneal topography, and epithelial thickness. Concurrently, participant feedback and reasons for any treatment discontinuation were documented.

RESULTS

Significant changes in refractive error and in corneal topography were observed, with approximately 50% of the refractive error being corrected on the first night of use and 100% by the first two weeks (P<0.001). Central epithelial thickness experienced substantial thinning, reducing to 15.65±4.49 μm (67.38%) (P<0.001) after 6 months of lens use. Six participants withdrew from this study for varied reasons, including unmet visual expectations and difficulty adhering to the lens-wearing regimen. Notably, the dropout group exhibited higher baseline low-order aberrations and less prolate corneas than those who persisted with the treatment (P<0.05).

CONCLUSION

Orthokeratology with CRT is efficacious and safe for the correction of low-to-moderate myopia in adults, but a portion of patients discontinue the treatment in the first 6 months of contact lens wear. Special care should be taken when recommending orthokeratology in patients with higher levels of myopia and corneas with less prolate shape, providing more realistic expectations and even changing to dual axis or more sophisticated designs.

Analysis on the correlation between long-term refractive regression and visual quality after FS-LASIK

PURPOSE

To record the long-term visual quality after FS-LASIK and analyze the effect of long-term refractive regression after corneal laser surgery on the visual quality.

METHODS

78 patients (153 eyes), who had undergone FS-LASIK more than 5 years before and had undergone follow-ups between November 2020 and March 2021. We collected data on the patients' age of surgery, postoperative period, and preoperative diopters (corrected to LogMAR 0.0 by mydriatic optometry). We obtained the measurements of ARC, PRC, THP by Pentacam, and extracted values for UCVA(LogMAR), CTRmsTotal, CTRmsHO, RmsTotal, RmsHO, MTFTotal, MTFHO, PSFTotal, PSFHO, Coma-T, Coma-CT, SA-T, SA-CT, Trefoil-T, and Trefoil-CT measured with OPD Scan III. We allocated the patients into emmetropia group (SE≤ -0.5D) 40 patients (78 eyes) and regression group (SE>-0.5D) 38 patients (75eyes) based on their postoperative diopters.

RESULTS

The values for postoperative periods, preoperative diopters, CTRmsTotal, CTRmsHO, and RmsTotal, Coma-CT, CTSA-CT in the emmetropia group were significantly lower than those in the regression group. The age of surgery, UCVA, MTFTotaL, MTFHO, PSFTotal, and CTPSF values in the emmetropia group were significantly higher than those in the regression group. The ARC, PRC, THP, RmsHO, Coma-T, SA-T, Trefoil-T and Trefoil-CT values were similar in both groups. There was no significant difference in preoperative sphere, spherical equivalent and BCVA between the two groups. There were significant differences in postoperative parameters at 1y, 3yrs and 5yrs. The postoperative diopter value was significantly correlated with age of surgery, postoperative period, THP, MTFTotal, PSFTotal, Coma-T, and SA-CT.

CONCLUSION

After FS-LASIK, young patients with relatively thin cornea are susceptible to refractive regression. With the extension of postoperative period, refractive regression may aggravate. There was no significant correlation between postoperative refractive regression and higher order aberrations.