Abstract
Purpose: :
To assess the efficacy, safety and stability of limbal relaxing incisions (LRIs) combined with cataract surgery.
Methods: :
A retrospective single centre UK study of consecutive patients undergoing LRIs combined with phacoemulsification, from 2002 to 2006 (group A). Patients were included if their pre-operative astigmatic refractive error was >1.5D. Outcomes were compared to age-matched patients with astigmatism <1.5 D who underwent phacoemulsification only (group B). Detailed examinations including corneal topography were performed pre-operatively, and post-operatively at 3 weeks and 3 months. LRIs were performed using the Nichamin nomogram, followed by phacoemulsification through a 2.5mm corneal tunnel, incorporated in one of the LRIs. Refractive and keratometric outcomes were analysed using the method of Kaye and Harris, as well as analysis of the change in refractive cylinder.
Results: :
Groups A (LRIs) and B (controls) had 43 patients each. Mean age was 74.6 and 74.3 years respectively. The mean pre-operative keratometry was also similar in both groups (difference = 0.68/0.18x135; p=0.11), although mean cylinder (as a scalar number) did show a large difference (2.44D, higher in group A). Analysis of the keratometric surgical effect (KSE) showed no significant difference between groups A and B post-operatively at 3 weeks (-0.10/0.21x94; p=0.94). Mean cylinder difference however was highly significant at 3 weeks (-1.49D; p<0.0001). The difference in KSE in group A between 3 weeks and 3 months post-operatively was also not significant (-0.10/0.39x3; p=0.57). The mean cylinder difference was again significant (+1.13D; p=0.0001), albeit notably showing an increasing cylinder. Postoperative best corrected visual acuity (BCVA) was at least 0.30 LogMar in 93% in group A and 86% in group B. One patient in group A developed cystoid macular oedema and two leaking wounds required temporary sutures. 3 patients in group B had a posterior capsular tear.
Conclusions: :
The addition of LRI to routine cataract surgery does not significantly increase surgical morbidity. If scalar analysis of cylinder alone is used then significant refractive change is achieved, although this effect seems to decrease with time. LRI however produced no significant difference in the mean keratometry or refractive error. In summary we are not able to demonstrate an overall benefit of LRI surgery in addition to routine cataract surgery, although larger studies are recommended in order to qualify this.
Keywords: refractive surgery: other technologies • small incision cataract surgery • refractive surgery: corneal topography