Abstract:AIM: To evaluate the efficacy and safety of Phorcides algorithm combined with Contoura Vision system in topography-guided myopic correction surgery, and compare its clinical outcomes with conventional wavefront-optimized(WFO)mode.
METHODS: A single-center open-label trial was conducted. Patients who underwent myopic correction surgery from June to December 2024 were enrolled and divided into two groups according to surgical protocols. The Phorcides algorithm combined with corneal topography-guided treatment constituted the Phorcides group, while conventional WFO treatment served as the WFO group. Both groups received surgery using the WaveLight EX500 excimer laser platform. In the Phorcides group, individualized ablation profiles were generated by the Phorcides software based on Topolyzer Vario topographic data. The WFO group underwent treatment with a standardized wavefront-optimized protocol.The primary outcome indicators included uncorrected distance visual acuity(UDVA), corrected distance visual acuity(CDVA), manifest residual spherical equivalent(MRSE), higher-order aberrations(HOAs, including spherical aberration C12, vertical coma C7, horizontal coma C8, trefoil aberration C6/C9)and incidence of postoperative complications at 3 mo after surgery.
RESULTS:This study enrolled 128 patients(256 eyes), including 64 patients(128 eyes)in the Phorcides group and 64 patients(128 eyes)in the conventional WFO group. The mean age was 28.1±5.3 y(34 males, 30 females)in the Phorcides group and 27.9±5.0 y(33 males, 31 females)in the WFO group.There were no significant inter-group differences in age, gender, preoperative MRSE and preoperative astigmatism and total higher-order aberrations(HOAs)between the two groups(all P>0.05). At 3 mo postoperatively, 1)visual acuity and refractive outcomes: the proportion of eyes achieving UDVA of 20/16 or better in the Phorcides group was 65.6%, which was obviously higher than 37.5% in the WFO group(χ2=22.18,P<0.001). MRSE in the Phorcides group was -0.07±0.14 D, significantly lower than -0.16±0.21 D in the WFO group(t=4.12, P<0.001), indicating closer alignment with the target refraction. The proportion of eyes with residual astigmatism ≤0.50 D reached 92.2% in the Phorcides group, which was 20.3% higher than 71.9% in the WFO group(χ2=16.35, P<0.001).Only one eye of one-line CDVA loss was observed in the WFO group, while no CDVA decline occurred in the Phorcides group; 2)higher-order aberrations: the total HOAs was 0.37±0.07 μm in the Phorcides group, markedly lower than 0.51±0.10 μm in the WFO group(t=12.84, P<0.001). Spherical aberration C12(0.21±0.05 μm), vertical coma C7(0.09±0.02 μm), and horizontal coma C8(0.08±0.02 μm)in the Phorcides group were all significantly lower than those in the WFO group(all P<0.001). No significant inter-group difference was found in postoperative trefoil aberration C6(P=0.056). Although there was a statistical difference in C9(P=0.022), its absolute difference was less than 0.06 μm with limited clinical significance. 3)complications: no severe adverse complications occurred in either group. Grade 1 diffuse lamellar keratitis(DLK)was found in 5 eyes(3.9%)in the Phorcides group and 7 eyes(5.5%)in the WFO group, with no significant difference in incidence between groups(χ2=0.42, P=0.517), and all of which were completely resolved after hormone therapy.
CONCLUSION:By integrating three-dimensional corneal topography data, the Phorcides algorithm can effectively improve the accuracy of myopia correction, reduce postoperative residual refractive error and accumulation of HOAs with reliable safety. It provides a superior individualized surgical strategy for patients with complex refractive errors.
