Estimation of Intraocular Lens Power Calculation Formula in Irregular Astigmatism With Normal Axial Length Eyes

We evaluated the intraocular lens power calculation (IOL) formulas in eyes with cataracts and irregular astigmatism who have undergone cataract surgery.

In a retrospective case series, 50 eyes with cataracts and irregular astigmatism who underwent phacoemulsification with IOL implantation were assessed. The IOL power was determined using the data of the keratometry of IOL master-derived keratometry in five formulas: Haigis, Hoffer Q, Holladay 1, SRK2  and SRKT. One month after surgery, refractive error and visual acuity were assessed.

The Mean±SD age of participants was 66.10±6.57 years (ranged 32-83). The percentage of male and female subjects was 45.8% and 54.2%, respectively. The axial length was 19.00mm to 23.00mm, which is a normal range. The most and least used formulas were SRKT and Haigis, respectively. Astigmatism and spherical refractive errors before and after surgery had significant differences (P<0.001). There was a decrease in astigmatism and hyperopic shift after surgery.

SRKT is a suitable formula for this group of patients. According to a decrease in astigmatism and hyperopic shift, an improvement in visual acuity can be expected.