Ptosis may impact IOL power, recent study suggests. Photo: Michael Trottini, OD. Click image to enlarge.

Lid malposition can cause changes in keratometry and astigmatism values. However, surgeons should consider altering the lens power accordingly if cataract surgery is to be sequentially followed by ptosis repair. A recent study in Journal of Cataract and Refractive Surgery evaluated the relationship between intraocular (IOL) lens power and involutional ptosis. The researchers reported a significant decrease in keratometry values and corneal astigmatism in patients with a ptosis of more than 4mm who have undergone anterior levator resection surgery. They noted that clinicians must be aware of the potential change in ocular biometric parameters.

The study included 57 eyelids of 57 Caucasian patients who had anterior levator resection surgery for involutional ptosis. The patients were divided into groups by droopy upper eyelid severity over the cornea: Group 1 >4mm (n=19), Group 2 3mm to 4mm (n=22) and Group 3 1mm to 2mm (n=16). The patients underwent anterior levator resection, and the researchers obtained preoperative and postoperative ocular biometry measurements.

The mean K1, K2 and Km values significantly decreased three months postoperatively in Group 1. The mean K1, K2 and Km values also decreased three months postoperatively in Groups 2 and 3, albeit non-significantly. The mean corneal astigmatism magnitude decreased three months postoperatively in all three groups. The mean recommended IOL powers targeting emmetropia increased postoperatively in Group 1 (0.50D) and were similar pre- and post-op in the other two groups.

As the severity of the ptosis increased, the power of the IOL also increased up to 1.00D. Under these circumstances, the researchers found it difficult to believe that this difference in severity was not clinically meaningful and suggested clinicians consider this condition to prevent post-cataract surgery refractive deviation. This deviation may be more problematic if a toric or multifocal IOL implantation is planned.

“The prior application of anterior levator resection and follow-up for a reasonable time may be more ideal for these patients before cataract surgery,” the researchers wrote in their paper. “Thus, if the severity of the ptosis is lower than these levels and no symptoms result from it, cataract surgery alone is suggested, without causing any refractive error.”