Initial Outcomes Of Transepithelial Photorefractive Keratectomy With Proscan Aspheric Treatment Compared With Octavius Topography-Optimised Treatment

Transepithelial photorefractive keratectomy (tPRK) is an excimer laser procedure wherein transepithelial surface ablation is combined with PRK to remove the epithelium and correct refractive error in a single optimised procedure. The TENEO Model 2 can be used to perform tPRK with different ablation profiles dependent on patient characteristics and desired outcomes. The PROSCAN aspheric treatment algorithm is designed to prevent a clinically significant increase of induced spherical aberrations. The OCTAVIUS procedure uses individual patient topography data to provide a customised corneal treatment. The purpose of this study was to compare the outcomes of tPRK with PROSCAN vs OCTAVIUS in patients with mild to high myopia.

This was a prospective, single-blind, single-centre study conducted at the OasisEye Specialists in Kuching, Malaysia, in patients presenting for refractive surgery for correction of myopia and astigmatism who had not received prior surgery. The TENEO Model 2 excimer laser platform was paired with the ACE diagnostic platform for advanced preoperative data accuracy.

11 consecutive patients (8 female, 3 males) received tPRK with the PROSCAN profile (PP) in one eye and OCTAVIUS profile (OP) in the fellow eye in an alternating OD/OS arrangement.Outcome measures included monocular uncorrected and best-corrected distance visual acuity (UDVA/BCDVA), induced higher order and spherical aberrations (HOA/SA), and contrast sensitivity at 1-month postoperatively. Target refraction for all eyes was −0.50D. Epithelial ablation thickness was set at 4µm above measured thickness, with optical coherence tomography to account for the surface fluid layer. The optical zone was centred on the pupil. Mitomycin C 0.02% was applied to the stromal surface for 30 seconds, followed by a 30 mL chilled basic salt solution rinse.

At baseline, mean±standard deviation (SD) age was 29.9±5.4 years. Mean±SD refractive error (sphere/cylinder) was −4.09±0.66/−1.16±0.63 (PP) and −3.80±0.93/−0.93±0.58 (OP). At one month, mean±SD logMAR UDVA was 0.03±0.10 (PP) and 0.06±0.10 (OP). Mean±SD BCVA was −0.02±0.04 (PP) and −0.02±0.04 (OP). Mean±SD induced HOA/SA were 0.41±0.22 μm/0.34±0.27 μm (PP) and 0.44±0.31 μm/0.33±0.25 μm (OP) These results were not statistically significant. (p>0.05). There was a statistically significant difference in contrast sensitivity. Mean±SD log contrast sensitivity was 1.91±0.17 (PP) and 2.04±0.09 (OP) (p<0.05). There were no perceived dysphotopic differences between eyes.

The initial results of this study demonstrate the effectiveness of the individualised OCTAVIUS treatment compared with the standard PROSCAN ablation profile on objective and subjective measures of visual acuity in patients with myopia and astigmatism. Utilising individual patient topography data showed similar outcomes on correction of myopia and an improvement on correction of astigmatism compared with standard treatment, without impacting subjective patient experience.