Session Title: Refractive II
Session Date/Time: Saturday 04/02/2012 | 08:30-11:00
Paper Time: 08:53
Venue: Grand Ballroom
First Author: : R.Lim SINGAPORE
Co Author(s): : L. Ilari
Purpose:
Limbal relaxing incision (LRI) is a common and inexpensive method of correcting astigmatism. It is often performed in conjunction with small incision cataract surgery when the patient is predicted to have >0.75D of residual astigmatism after cataract extraction alone. However, the stability of its effect over time is still not fully understood. Studies in the literature have reported that its astigmatic correction does not regress up to a year after surgery. Beyond 1 year of follow-up, information is limited.
Our study investigates the stability of the effects of LRIs with more than 2.5 years of follow-up.
Setting:
The study was carried out at the Princess Royal University Hospital, South London Healthcare Trust, NHS, UK.
Methods:
26 patients (33 eyes) underwent LRI at our institution between November 2006 and November 2008. Long-term follow-up data were available for 17 patients (22 eyes). Corneal astigmatism and topography information were captured using the Pentacam. This was compared to records collected pre-operatively, 2 weeks post-operatively and 6 weeks post-operatively.
Both average keratometric astigmatism and average surgically induced astigmatism (SIA) were studied. SIA was calculated using the AstigPLOT, EyePro 2011. Statistical analysis was performed using Wilcoxon 2-tailed matched-pair test. RESULTS We studied 22 eyes of 17 patients. Average age at surgery was 77.9 years (min 49.8 years, max 86.9 years). Average length of follow-up was 3.41 years (min 2.58 years, max 4.24 years).
Average keratometric astigmatism was 2.26D (min 1.2D, max 3.6D) pre-operatively, 1.31D (min 0.3D, max 4D) at 2 weeks follow-up, 1.24D (min 0.2D, max 3.9D) at 6 weeks follow-up and 1.23D (min 0.4, max 4.7D) at an average of 3.41 years follow-up. There was no statistically significant difference between the average keratometric astigmatism at 2 weeks and 6 weeks follow-up (p=0.28), nor between 6 weeks and 3.41 years follow-up (p=0.99). Average keratometric astigmatism at 3.41 years follow-up was significantly different to that pre-operatively (p=0.0007).
Average SIA was 2.64D (min 0.62D, max 5.2D) at 2 weeks follow-up, 1.96D (min 0.7D, max 3.89D) at 6 weeks follow-up and 2.05D (min 0.83D, max 4.07D) at an average of 3.41 years follow-up.
SIA at 2 weeks follow-up was significantly different to that at 6 weeks follow-up (p=0.0004). However, SIA at 3.41 years follow-up was not significantly different to that at 6 weeks follow-up (p=0.28).
Subgroup analysis of with-the-rule and against-the-rule astigmatism showed similar trends to the main group analysis.
Conclusions:
In our study, both analyses of average keratometric astigmatism and SIA suggest that the astigmatic effects of LRIs remain stable from 6 weeks post- operatively to our average follow-up of 3.41 years. There is some variability from 2 to 6 weeks post-operatively as indicated by the significant difference in SIA. Overall, LRIs remain an attractive option for reducing astigmatism, given its stability over time.
Financial Disclosure:
No
