Change in intraocular lens power calculation results after ptosis surgery.

[PURPOSE] To evaluate the difference between intraocular lens power calculation and ocular biometric parameters before and after anterior levator resection surgery (ALR).

[METHODS] In this prospective study, patients with involutional ptosis who underwent ALR surgery were included. Ocular biometric parameters were obtained preoperatively and 3 and 6 months postoperatively.

[RESULTS] Forty-five patients with ptosis were selected for the study, 25 eyes had only ALR surgery, and 20 eyes had both ALR and upper lid blepharoplasty. The mean keratometry (Km) value significantly decreased from the preoperative value at 3 months postoperatively (P=0.026) and did not change between 3 and 6 months (P=0.4). The mean preoperative MRD-1 level was 0.86±1.1mm, 3.4±0.9mm at 3 months, and 3.45±1mm at 6 months postoperatively (P=0.0001). The mean IOL power targeting emmetropia increased at 3 months postoperatively (P=0.041) and did not change between 3 and 6 months (P=0.2). There was a negative correlation between MRD-1 level, K1, K2 and Km after 6 months (r: -0.171, P: 0.02; r: -0.334, P: 0.04; r: -041, P: 0.001 respectively), whereas there was a positive correlation between MRD-1 level and IOL power after 6 months (r: 0.348, P: 0.04). The mean Km, IOL power and MRD-1 levels were not statistically different between ALR-only patients and ALR-blepharoplasty patients at 6 months postoperatively (P: 0.2, 0.07, 0.32 respectively).

[CONCLUSION] Ptosis surgery can affect IOL power postoperatively due to keratometric changes, and these changes stabilize at 3 months after surgery. Keratometric measurements have been shown to be related to postoperative eyelid position.