Intraocular Lens Power and Corneal Topographic Change After Pterygium Surgery

To investigate the impact of pterygium excision on intraocular lens (IOL) power calculation and corneal astigmatism.

Prospective cohort study.

We enrolled 30 eyes with primary pterygium that underwent pterygium excision with a conjunctival autograft. IOL power calculation and keratometry using the IOL Master 700, along with topographic parameters using the Pentacam Scheimpflug topography system, were performed preoperatively and at 1, 3, 6, and 12 months postoperatively. We analyzed correlations between pterygium length/area and IOL power, as well as corneal topographic changes.

The mean pterygium length was 2.08 ± 0.58 mm, and the mean area was 6.05 ± 2.41 mm². One year after pterygium surgery, the calculated IOL power values using all formulas were lower than the preoperative values. Pterygia with a horizontal length of 1.73 mm and an area of 4.45 mm² and those with a horizontal length of 2.25 mm and an area of 6.95 mm² created 0.5 diopters (D) and 1.0 D errors in calculated IOL power, respectively (P < .001). The calculated IOL power values changed significantly from preoperative to 6 months postoperatively but did not change significantly from 6 to 12 months postoperatively. Pterygia with a horizontal length >1.83 mm (P < .001) and an area >5.1 mm² (P < .001) created a 2.0 D error in anterior corneal astigmatism.

Pterygium causes errors in IOL power calculation, with greater pterygium length/area exerting a larger effect. Cataract surgery with IOL implantation is recommended ≥6 months after pterygium surgery. In combined cases, calculated IOL power should be decreased by 0.5 to 1.5 D based on the pterygium length/area.