The Impact of Different Center Alignment on Visual Quality Following Corneal Refractive Surgery: A Systematic Review and Meta-analysis

Purpose: To systematically evaluate the effect of different centration methods on postoperative visual quality in patients with refractive error undergoing corneal refractive surgery. Methods: Overall, 3,140 eyes from 65,604 records were retrieved through a comprehensive search of eight databases. Thirteen studies were included in the meta-analysis to evaluate the impact of centration methods on visual quality outcomes. Results: Postoperative decentration was significantly lower in the coaxially sighted corneal light reflex (CSCLR)–centered group than in the entrance pupil center (EPC)–centered group ( P < .05). The proportion of spherical equivalent (SE) within ±0.50 diopters (D) were significantly better in the CSCLR-centered group ( P = .001). However, no significant differences were found in postoperative uncorrected distance visual acuity (UDVA), postoperative corrected distance visual acuity (CDVA), the proportion of eyes achieving 20/20 or better UDVA, loss of two or more lines of CDVA, or astigmatism (all P > .05). Induced coma was significantly lower in the CSCLR-centered group ( P < .00001), with no significant difference in sphere or other higher order aberrations (HOAs). Significant differences in HOAs were observed between angle kappa of 0.2 mm or greater and angle kappa less than 0.2 mm groups ( P = .03), although no significant differences were found in postoperative UDVA, SE, sphere, or horizontal coma/vertical coma (all P > .05). Conclusions: CSCLR centration ablation might have a potential advantage over EPC centration in achieving better postoperative outcomes (SE residuals, and induced coma) after corneal refractive surgery according to the currently available low-quality evidence. When the preoperative angle kappa is large, an angle kappa adjustment is suggested. More high-quality trials are required in future research.