Refractive outcomes after cataract phacoemulsification with intraocular lens implantation in patients with different axial eye lengths

Abstract

Objective.  To assess the frequency of achieved postoperative emmetropic refraction after cataract phacoemulsification with intraocular lens (IOL) implantation in patients with different preoperative refractive profiles, and to compare refractive outcomes with axial length (AL). Materials and methods.  This retrospective comparative study included 129 eyes of 129 patients aged 65.4±9.8 years old. According to the spherical equivalent (SE), the groups were classified as hyperopic (n=21), emmetropic (n=85), or myopic (n=23). Postoperative refraction was assessed no sooner than 1 month after surgery. The primary index was the absolute distance of postoperative SE from emmetropia. Strict emmetropia was defined as SE between -0.25 and +0.25 D, additionally proportions within ±0.50 D and ±1.00 D were analyzed. Individual target refraction was not documented for the entire cohort, therefore, refractive prediction error was not calculated. Results.  Mean AL was 22.4±1.1 mm in the hyperopic group, 23.8±1.3 mm in the emmetropic group, and 26.9±2.4 mm in the myopic group (p<0.001). Strict emmetropia was achieved in 59 eyes from 129 (45.7%): in 42.9%, 48.2%, and 39.1% of cases respectively (p=0.709). Postoperative SE was within ±0.50 D in 71.3% of eyes overall, including 66.7% in patients with intact hyperopia, 72.9% with emmetropia, and 69.6% with myopia (p=0.833). A deviation greater than 1.00 D occurred in 10.9% of patients. Its highest frequency was in the group with the shortest AL: 14.3% versus 9.4% in the intermediate-AL group and 13.0% in the longest-AL group (p=0.759). Thus, with intermediate AL, the highest proportion of results close to emmetropia was observed, whereas with extreme AL values, the proportion of pronounced deviations was higher, but the intergroup differences did not reach statistical significance. Conclusion.  Strict postoperative emmetropia was achieved in 45.7% of eyes, while 71.3% were within ±0.50 D of emmetropia. AL differed significantly between preoperative refractive groups. The highest proportion of deviations greater than 1.00 D was observed in the group with a short AL, and the highest frequency of results within ±0.50 D was observed in the group with an emmetropic axial length. The obtained data justify taking into account AL when analyzing the postoperative refractive result, but do not allow considering AL as an independent predictor of deviation without individual multivariate analysis.