PURPOSE: To compare changes in corneal shape and in regular and irregular corneal astigmatism after 3.0- or 2.0-mm clear corneal incision cataract surgery (CICS) with those occurring after 3.0- or 2.0-mm scleral incision cataract surgery (SICS). DESIGN: Randomized, comparative clinical trials. PARTICIPANTS: Ninety patients scheduled for bilateral cataract surgery were randomized to 1 of 2 groups: 3.0- or 2.0-mm CICS in the left eye and 3.0- or 2.0-mm SICS in the right eye or CICS in the right eye and SICS in the left eye. INTERVENTION: All patients underwent CICS and SICS at the 9-o'clock meridian in fellow eyes. MAIN OUTCOME MEASURES: Induced corneal astigmatism was determined using vector analysis, and the averaged changes in corneal shape and irregular astigmatism were examined using videokeratography before surgery and at 2 days and 1, 2, 4, and 8 weeks after surgery. RESULTS: For the 3.0-mm incision, induced astigmatism was significantly greater in the CICS group than in the SICS group (P < or = 0.0329) at 2 weeks and later. The average of difference map on videokeratography in the CICS group showed a marked wound-related flattening and coupled steepening around the flattened area at 2 days after surgery, and these changes persisted for up to 8 weeks: the changes were markedly less in the SICS group. Among the irregular astigmatic components, higher-order irregularity in the CICS group was greater than that in the SICS group (P<0.0001). For the 2.0-mm incision, no significant difference was found between the CICS and SICS groups in induced astigmatism or in irregular astigmatic components. The average of difference map of the CICS group showed a slight wound-related flattening around the incision at 2 days after surgery, but this decreased by 2 weeks; the map of the SICS group showed little change. CONCLUSIONS: Changes in corneal astigmatism and shape after 2.0-mm CICS are virtually the same as those after 2.0-mm SICS, whereas those occurring after 3.0-mm CICS are significantly greater than those occurring after 3.0-mm SICS, which suggests that CICS is suitable for microincision cataract surgery. FINANCIAL DISCLOSURE(S): The author(s) have no proprietary or commercial interest in any materials discussed in this article. Copyright 2010 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.
RCT Entities:
PURPOSE: To compare changes in corneal shape and in regular and irregular corneal astigmatism after 3.0- or 2.0-mm clear corneal incision cataract surgery (CICS) with those occurring after 3.0- or 2.0-mm scleral incision cataract surgery (SICS). DESIGN: Randomized, comparative clinical trials. PARTICIPANTS: Ninety patients scheduled for bilateral cataract surgery were randomized to 1 of 2 groups: 3.0- or 2.0-mm CICS in the left eye and 3.0- or 2.0-mm SICS in the right eye or CICS in the right eye and SICS in the left eye. INTERVENTION: All patients underwent CICS and SICS at the 9-o'clock meridian in fellow eyes. MAIN OUTCOME MEASURES: Induced corneal astigmatism was determined using vector analysis, and the averaged changes in corneal shape and irregular astigmatism were examined using videokeratography before surgery and at 2 days and 1, 2, 4, and 8 weeks after surgery. RESULTS: For the 3.0-mm incision, induced astigmatism was significantly greater in the CICS group than in the SICS group (P < or = 0.0329) at 2 weeks and later. The average of difference map on videokeratography in the CICS group showed a marked wound-related flattening and coupled steepening around the flattened area at 2 days after surgery, and these changes persisted for up to 8 weeks: the changes were markedly less in the SICS group. Among the irregular astigmatic components, higher-order irregularity in the CICS group was greater than that in the SICS group (P<0.0001). For the 2.0-mm incision, no significant difference was found between the CICS and SICS groups in induced astigmatism or in irregular astigmatic components. The average of difference map of the CICS group showed a slight wound-related flattening around the incision at 2 days after surgery, but this decreased by 2 weeks; the map of the SICS group showed little change. CONCLUSIONS: Changes in corneal astigmatism and shape after 2.0-mm CICS are virtually the same as those after 2.0-mm SICS, whereas those occurring after 3.0-mm CICS are significantly greater than those occurring after 3.0-mm SICS, which suggests that CICS is suitable for microincision cataract surgery. FINANCIAL DISCLOSURE(S): The author(s) have no proprietary or commercial interest in any materials discussed in this article. Copyright 2010 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.