Effect of crystalline lens on visual quality in pterygium patients before surgery

Abstract

Purpose: The aim of our study was to assess the visual quality of pterygium patients with total ocular aberrations, and not only corneal aberrations. Methods: 46 eyes of 37 pterygium patients (mean age 48 ± 15 years) were evaluated in a retrospective study. Inclusion criteria were primary pterygium, without any previous surgical treatment. Before surgery, subjective refraction, corrected distance visual acuity (CDVA), with an EDTRS optotype chart, and Zernike coefficients for a 5 millimetres (mm) pupil diameter measured with an Alcon LadarWave total aberrometer (Fort Worth, Texas, USA) were determined. Pterygium size in mm was measured by an experienced ophthalmologist using a slit beam of light from the limbus to the limit of the pterygium. Statistical analysis was performed using SPSS software version 26.0. The Kruskal‐Wallis test with the Tukey–Kramer criterion was used to examine the influence of the extent of corneal invasion on manifest refraction and Zernike coefficients. One‐way analysis of variance (ANOVA) with the Bonferroni criterion was performed to compare different extent values. A p value less than or equal to 0.05 was considered statistically significant. Results: The sample was divided in four groups, according to the extent of corneal invasion. The upper limits of each category were 1, 2, 3 and 4 mm, with 9, 20, 11 and 6 patients in each group, respectively. Preoperatively spheres more positive were found at high corneal invasion groups, statistically significant between 1 and 3 mm, and between 2 and 3 mm (p = 0.013 and p = 0.011) and cylinder axes were between 20° and 50° in all groups. CDVA was lower in patients with greater corneal invasion. Regarding total ocular aberrations, statistically significant differences between groups were found only in a reduced set of Zernike polynomials but oblique astigmatism (2,‐2) appeared in most of the comparatives. Most of the Zernike coefficients, were out of normal limits, compared to control values, including spherical aberration. Conclusions: Pterygium‐induced aberrations also modify the visual quality of patients when the effect of the crystalline lens aberrations is considered, the conclusions are similar to those derived from corneal aberrations. CDVA was lower preoperatively in patients with greater corneal invasion (4 mm).