Limbal relaxing incisions during cataract surgery: vector analysis and subgroup analysis of a large cohort of 465 eyes

Session Details

Session Title: Combined Cataract Surgery: Techniques/Practice Styles

Session Date/Time: Tuesday 13/09/2016 | 14:00-16:00

Paper Time: 15:00

Venue: Auditorium C6

First Author: : S.Farrell IRELAND

Co Author(s): :    P. Mullaney                    

Abstract Details

Purpose:

To analyse the efficacy of standard LRI in correcting astigmatism of between 1.5D and 6D in a large cohort of patients undergoing cataract surgery in a high volume public hospital setting and to perform subgroup analysis based on the amount of pre-operative astigmatism, the orientation of pre-operative astigmatism (with the rule, oblique or against the rule), the age of the patient and the level of experience of the surgeon.

Setting:

Sligo Regional Hospital, Sligo, Republic of Ireland. A high volume public hospital setting.

Methods:

All patients undergoing limbal relaxing incision with a pre-operative keratometric astigmatism of 1.50 to 6.00 D over a six year period were analysed. Vector based analysis was performed to assess the error in the magnitude of flattening and the error in the axis at which flattening occurred. The cohort was sub grouped based on degree of astigmatism, age, orientation of astigmatism and surgeons experience. Subgroup analysis using unpaired student t-tests was performed.

Results:

465 eyes underwent analysis. Mean pre-operative keratometric astigmatism was 2.35D ± 0.79 (SD). Mean post-operative refractive astigmatism was 1.35D ± 0.87 (SD). Vector based analysis showed that mean error in the magnitude of flattening was 0.12D ±1.40 (SD). The mean absolute error in the magnitude of flattening was 1.15D ± 0.82 (SD). The mean absolute angle error was 17.14 degrees ± 22.28 (SD). Both magnitude error and angle error were normally distributed. Subgroup analysis showed eyes with higher levels of astigmatism pre-operatively had significantly higher levels of astigmatism post-operatively. Eyes with against-the-rule astigmatism had significantly higher levels of astigmatism post-operatively. There was no difference in astigmatism outcome between patients of varying ages age or between very experienced surgeons and trainees.

Conclusions:

In this, the largest reported study of LRIs to date, we show that LRIs reduce astigmatism in most cases with an average reduction in astigmatism of 42%. Vector analysis shows that residual astigmatism is due both to a variation in the magnitude of flattening which occurs and variation in the angle at which it occurs. The best outcomes occur in patients with lower pre-operative astigmatism and with with-the-rule astigmatism. We show definitively that patients of varying ages have equally successful outcomes. The technique does not require high levels of experience with similar outcomes between trainees and highly experienced surgeons

Financial Disclosure:

NONE