ABSTRACT
Purpose: To study the effect of wound size modulation on pre?existing astigmatism by on?axis placement of incision in manual small?incision cataract surgery (MSICS). Methods: In this prospective interventional study conducted at a tertiary care centre, 40 eyes of 40 consecutive senile cataract patients with 1.00�00 D corneal astigmatism were enrolled for the study. MSICS by modified Blumenthal抯 technique was performed through 6.0, 6.5, and 7.0 mm on?axis incision in 1.0�49 D (group A), 1.50�99 D (group B), and 2.00�00 D (group C) astigmatism, respectively. Surgically induced astigmatism (SIA) was calculated by vector analysis and double angle plots (DAP) at 12 weeks postoperatively. Results: There were 22 males and 18 females with mean age of 58.12 � 1.18 years. The mean SIA at 12 weeks was 0.85 � 0.28 D in group A (17 eyes), 1.32 � 0.65 D in group B (10 eyes), and 1.91 � 0.69 D in group C (13 eyes). The overall median uncorrected visual acuity was 0.18 (IQR = 0 to 0.2). The mean astigmatism decreased from 1.95 � 0.74 D to 1.04 + 0.57 D (P = 0.00) in superior incision and from 1.70 + 0.50 D to 0.92 � 0.45 D (P = 0.00) in temporal incision group with central shift of centroid in all cases. Conclusion: The customization of on?axis external incision size can be used to manage pre?existing corneal astigmatism of less than 3.00 D using both temporal and superior incisions effectively
ABSTRACT
Introduction: Globally cataract is the major cause for blindness. About 75% of cases preventable causes of blindness in developing countries are attributed to cataract. As per available literature so many studies are available to study how to control the surgically induced astigmatism in variety of cataract surgeries. In the current study we aimed to focus on the effect of factors like wound modulation, and also role of superior or temporal scleral tunnel incisions on the post-operative astigmatism. Objective: To study the effect of wound modulation on postoperative astigmatism following manual small incision suture less scleral tunnel cataract surgery by either superior or temporal incision. Materials and methods: The study was a hospital based quasi experimental study, conducted in the department of ophthalmology at NRI Medical College and General Hospital, Chinakakani, Andhra Pradesh state from August 2014 to August 2015. A total of 100 randomly selected subjects undergoing cataract surgery by suture less non phaco small incision sclera tunnel technique were included. Results: 36% of the patients included in this study for superior small incision sutureless non phaco cataract surgery pre operatively had with the rule astigmatism and 42% had against the rule astigmatism and no astigmatism is seen in 22% of cases. Pre operatively 34% of the patients included Chimata T, Tirumuru D, Chowdary NL. A study of the effect of wound modulation on postoperative astigmatism following manual small incision suture less scleral tunnel cataract surgery. IAIM, 2016; 3(7): 345-352. Page 346 in this study for temporal small incision suture less non phaco cataract surgery had with the rule astigmatism and 48% had against the rule astigmatism and no astigmatism is seen in 18% of cases. In cases subjected to superior small incision suture less non-phaco cataract surgery showed against the rule astigmatism and in 72% and with the rule in 20% and no astigmatism in 4% of cases. In cases subjected to temporal small incision suture less cataract surgery had surgically induced astigmatism of with the rule in 84% and only 8% had against the rule and no astigmatism was found in 8% of cases. At six weeks 86% of cases subjected to superior small incision suture less non –phaco cataract surgery had surgically induced astigmatism of against the rule type and in 12% with the rule type and 2% had no astigmatism. In cases subjected to temporal small incision suture less non-phaco cataract surgery there was surgically induced astigmatism of with the rule type in 86% of cases ad 8% of against the rule type and 6% had no astigmatism. In cases subjected to temporal suture less non – phaco small incision cataract surgery induced astigmatism by 3 weeks was 0.69D in with the rule type and 0.31D in against the rule type and the average total was about 0.66D. By 6 weeks the mean surgically induced astigmatism in superior SICS was 0.71D in with the rule type and 1.51D in against the rule type and an average of 1.01D in total. In cases subjected to temporal SICS it was 0.69D in with the rule type and 0.33D in against the rule type and a total of 0.66 D by 6 weeks. Conclusion: Temporal small incision cataract surgeries shows less induced astigmatism whereas superior small incision cataract surgeries higher SIAS values.