T Iwase1, N Tanaka, K Sugiyama. 1. Department of Ophthalmology, Toyama Red Cross Hospital, Toyama and Department of Ophthalmology, Toyama Prefectural Central Hospital, Toyama - Japan. Tsuyoshilwase@aol.com
Abstract
PURPOSE: To examine postoperative refraction changes following phacoemulsification cataract surgery and to assess their influential factors, including intraocular lens (IOL) materials and anterior chamber depth (ACD) of the implanted IOL. METHODS: In this prospective study, 339 eyes were randomly assigned to receive a rigid polymethylmethacrylate (PMMA) IOL (811C or 824C), an acrylic IOL (MA60BM), or a silicone IOL (AQ110NV). All patients were followed for 48 weeks after surgery. Postoperative spherical equivalent refraction and ACD were measured by a refractometer and by an anterior eye segment image analyzer, respectively. RESULTS: In the silicone IOL group, statistically significant myopic shift was observed at 8 weeks after the surgery and continued throughout the follow-up period. Mean myopic shift at the end (48 weeks) was -0.53 D. Concomitantly shortened ACD was also confirmed at 12 weeks after the surgery. In the other groups, postoperative refraction and IOL position did not change after surgery. CONCLUSIONS: The eyes with silicone IOL caused postoperative myopic shift due to the anterior IOL movement. It is important to be aware of the characteristics of each IOL and to take myopic shift into consideration when silicone IOL is implanted. Preferably the A-constant for silicone IOL should be reconsidered to obtain rather accurate postoperative refraction.
RCT Entities:
PURPOSE: To examine postoperative refraction changes following phacoemulsification cataract surgery and to assess their influential factors, including intraocular lens (IOL) materials and anterior chamber depth (ACD) of the implanted IOL. METHODS: In this prospective study, 339 eyes were randomly assigned to receive a rigid polymethylmethacrylate (PMMA) IOL (811C or 824C), an acrylic IOL (MA60BM), or a silicone IOL (AQ110NV). All patients were followed for 48 weeks after surgery. Postoperative spherical equivalent refraction and ACD were measured by a refractometer and by an anterior eye segment image analyzer, respectively. RESULTS: In the silicone IOL group, statistically significant myopic shift was observed at 8 weeks after the surgery and continued throughout the follow-up period. Mean myopic shift at the end (48 weeks) was -0.53 D. Concomitantly shortened ACD was also confirmed at 12 weeks after the surgery. In the other groups, postoperative refraction and IOL position did not change after surgery. CONCLUSIONS: The eyes with silicone IOL caused postoperative myopic shift due to the anterior IOL movement. It is important to be aware of the characteristics of each IOL and to take myopic shift into consideration when silicone IOL is implanted. Preferably the A-constant for silicone IOL should be reconsidered to obtain rather accurate postoperative refraction.