Impact Of Uncorrected Astigmatism On Postoperative Visual Quality Following Evo-Icl Implantation In Moderate And High Myopia With Diverse Astigmatism Proportions

To evaluate and compare postoperative visual quality in myopic patients with varying degrees of astigmatism following either full correction with toric implantable collamer lens (TICL) implantation or no astigmatism correction with ICL implantation.

This study included 80 eyes from 40 patients (18 males and 22 females) aged 26.61 ± 7.52 who underwent ICL/TICL V4c implantation. The astigmatism proportion (A%) was defined as the ratio of dioptric cylinder (DC) to dioptric sphere (DS) derived from preoperative subjective refraction. Patients with an A% of 25.67 ± 10.87% underwent TICL implantation, whereas those with an A% of 11.02 ± 2.70% received ICL implantation.

All enrolled patients achieved a postoperative corrected distance visual acuity (CDVA) of ≥ 20/20. Preoperative and 3-month postoperative evaluations included measurements of uncorrected distant visual acuity (UDVA), corrected distance visual acuity (CDVA), intraocular pressure (IOP), spherical equivalent (SE), and wavefront aberrations for 4 mm and 6.5 mm optical zones (OZ₄ and OZ_6.5). Objective and subjective visual quality assessments were conducted 3 months postoperatively using PSF, MTF, contrast sensitivity (CS), and the Quality of Vision (QoV) questionnaire score.

No statistically differences were observed between the two groups in terms of preoperative and postoperative UDVA, CDVA, IOP, or SE. Postoperatively, significant reductions were observed in the TICL group for the C3 (45/135° astigmatism), C5 (90/180° astigmatism) and C11 (secondary astigmatism) within both the OZ₄ and OZ_6.5, whereas these aberrations exhibited an increase in the ICL group (P < 0.05). Notably, these reductions were more pronounced in the TICL group within the OZ_6.5 (P < 0.05). The RMS of total ocular aberrations, HOAs, and C4 (spherical defocus) decreased postoperatively, with no significant differences between the TICL and ICL groups. No significant intergroup differences were observed in MTF, PSF or VoQ scores.

The degree of correction for spherical defocus plays a critical role in determining postoperative visual quality following refractive surgery. TICL implantation demonstrated efficacy in significantly reducing postoperative astigmatism-related aberrations, particularly within larger optical zones. In contrast, the uncorrected residual astigmatism (11.02% of preoperative cylindrical power) resulted in increased astigmatism-related aberrations. The uncorrected astigmatism did not significantly influence the correction of spherical defocus, particularly within the central optical zone, which consequently had no significant impact on postoperative subjective visual quality.