Modeling of the results of laser correction of hyperopia by the methods of cluster and discriminant analysis

Statistical methods are used to solve the problem of evaluating refractive results in patients The issue of optimizing refractive laser surgeries for hyperopia correction remains relevant, as current keratorefractive surgery methods for hyperopia are less predictable, effective, and stable com- pared to myopia correction. This non-randomized retrospective study includes the results of 161 patients who underwent FemtoLASIK laser correction at the Cheboksary branch of National Med- ical Research Center "Eye Microsurgery". The average age of the patients was 41.9 years. Eval- uations were conducted before surgery and on the third day postoperatively using standard exam- ination methods, including uncorrected and best-corrected visual acuity, refractometry, non-con- tact tonometry, biomicroscopy, keratotopography, anterior segment analyzer examination, and fundus examination, among other parameters. Through cluster and discriminant analyses, a "risk group" was identified, showing the least accuracy in postoperative spherical equivalent and the lowest visual acuity indicators. A rule was developed to categorize eyes into one of the groups. The best refractive outcomes were observed in the low-degree hyperopia group, while the "risk group" included patients with high-degree hyperopia, either alone or in combination with astigma- tism. Pairwise comparisons indicated that cases from the "risk group" more frequently fell into groups with the highest (by absolute value) cylindrical component of refraction and the lowest spherical equivalent postoperatively, explaining the low uncorrected and best-corrected visual acu- ity indicators. High-degree hyperopia requires longer laser ablation time, which can lead to corneal dehydration and uneven ablation, as well as the induction of higher-order aberrations and astig- matism formation. Accommodative disorders in hyperopic patients may lead to prolonged myopic refraction postoperatively. Correction of low and moderate hyperopia using FemtoLASIK shows more accurate results compared to high-degree hyperopia correction. To improve outcomes, it is necessary to consider the degree of hyperopia, age, accommodative apparatus tone, presence of optical correction, binocular interaction characteristics, and Kappa angle during surgery planning and postoperative management. These measures can lead to more predictable and stable results, reduce the risk of complications, and enhance patient satisfaction with the treatment.