Wavefront - guided PRK produces better optical results than wavefront - guided or optimised LASIK

WAVEFRONT-guided photorefractive keratectomy (PRK) induces fewer higher-order aberrations than wavefrontguided LASIK, while the latter induces fewer higher order aberrations than conventional or optimised LASIK, suggest the preliminary results of two new studies presented at the XXIII Congress of the ESCRS. “In my practice, I employ wavefront guided technology in every patient that is eligible,” said Steve Schallhorn MD, director of the Refractive Surgery Center at the Naval Medical Center in San Diego, California. In the first study, 58 patients received wavefront-guided PRK or wavefront-guided LASIK.The surgeons used the Amoils brush for the PRK treatments, and the Hansatome microkeratome or the IntraLase femtosecond laser for the LASIK procedures.They used the Fourier VISX Star S4/ WaveScan 3.62 system for both types of procedures, using an identical ablation profile with no nomogram adjustment. After three months, 91% in the PRK group and 88% in the LASIK group were within 0.50 dioptre of the intended treatment target. Moreover, 75% of the PRK treated eyes and 63% of the LASIK treated eyes were within 0.25 dioptre of the treatment goal. Three months after the procedure, 97 % of the LASIK group and 89% of the PRK group achieved an uncorrected visual acuity of 20/20, and 95% of the LASIK eyes and 79% of the PRK eyes achieved an uncorrected visual acuity of 20/16. Half of the PRK eyes achieved 20/12.5 uncorrected visual acuity as did 35% of the LASIK-treated eyes. The average post-operative uncorrected acuity was better than the average best spectacle corrected acuity before surgery. This was true for both the PRK treated and the LASIK treated eyes. Both methods lead to a slight improvement in bestcorrected visual acuity and photopic low contrast acuity and no average loss of scotopic contrast acuity. While PRK and LASIK performed comparably in all of the above-mentioned areas, there was a significant difference between the two wavefrontguided treatments when it came to higher order aberrations. Wavefront-guided PRK induced significantly fewer higher order aberrations than LASIK.The difference was particularly noted when it came to coma aberrations. However, the difference in higher order aberrations could be due to the type of keratome the surgeons used, according to Dr Schallhorn. Dr Schallhorn considers his results preliminary, and he is planning on enrolling a larger number of subjects. In addition, the patients will be followed for twelve months after surgery to see if some continue to improve.