Evaluation of Visual Acuity and Refractive Errors after IOL Placement in Cataract ‎Patients with Regular Astigmatism

Astigmatism is a common refractive error and is common in patients requiring cataract surgery. Cataract surgery is usually accompanied by an intraocular lens (IOL) implantation. However, global sanctions in Iran and the high cost of toric IOLs sometimes lead to the application of spherical IOLs and hence residual astigmatism. Given the average age of the middle-aged Iranian population, the need to address the issue of astigmatism and cataracts is clear. To evaluate the visual acuity and refractive errors in cataract patients with regular astigmatism after spherical IOL placement and to evaluate the results of the calculation formulas for determining IOL power.

This cross-sectional study was performed on 100 eyes of 72 patients aged 50 to 75 years with regular astigmatism who underwent phacoemulsification surgery and simultaneous spherical IOL implantation at Farabi Eye Hospital in Tehran. Patients' visual acuity was performed by LogMAR chart and refractive examination using Topcon autokeratorefractor preoperatively and one month after surgery. The results of preoperative and postoperative examinations, according to the formula used and target refraction, were statistically analyzed using analysis of variance, paired t-test, and Pearson correlation in SPSS software.

The selection of “Plano” target refraction, improved patients' vision and refraction. The mean of Uncorrected Distance Visual Acuity before and after surgery showed a significant difference (p<0.001). The mean of Corrected Distance Visual Acuity and spherical refractive error before and after surgery did not show a statistically significant difference (p>0.05). The mean of refractive and corneal astigmatism, before and after surgery showed a significant difference (p<0.001).

The age of cataract patients with astigmatism can be an indicator for choosing the appropriate IOL formula. Cataracts cause astigmatism by altering the Crystalline lens, which can be reduced with surgery. With accurate refraction, the quality of patients' vision can be increased with spectacles before cataract surgery. The SRK / T formula, which has the highest frequency among the three formulas, has better visual and refraction results.