Abstract
Purpose: :
We report on the precision, reproducibility and efficacy of an OCT-guided femtosecond laser cataract system to facilitate and automate the anterior capsulotomy and lens disassembly.
Methods: :
In a randomized clinical trial, 29 patients underwent cataract surgery in both eyes. One randomly assigned eye received capsulotomy and lens fragmentation with a femtosecond laser (Catalys, Optimedica) while the other acted as a control eye with standard manual anterior capsulotomy and lens fragmentation. The excised capsulotomy disc was removed, followed by phacoemulsification and placement of an intraocular lens. Calibrated high definition video microscopy was used to measure the excised capsulotomy disc. The shape and diameter of the anterior capsular disc as well as centration of the resulting opening were assessed. Cumulative Dispersed Energy (CDE) was recorded and analyzed with respect to study arm and cataract grade (LOCS).
Results: :
The average deviation of the capsulotomy disk diameter from intended was 29um ± 25um with laser and 329um ± 250um with manual capsulorrhexis. With 1.0 defining a perfect circle, the average circularity for laser capsulotomies was 0.94 ± 0.04, while for manual CCC it was 0.77 ± 0.15. Cataracts with LOCs grade 1 to 4 were treated in both groups with 50% of cataracts being grade 3. On average the CDE was reduced by 40% from 18.9 (manual) to 11.6 (laser). All results were statistically significant with p < 0.05.
Conclusions: :
Deviation of the diameter of the anterior capsulotomies produced by femtosecond laser from intended was 12 times smaller and deviation from round shape 4 times lower than those with manual CCC. Pre-conditioning of the cataract with the femtosecond laser reduced the CDE by 40%, which might lead to reduction of surgical side-effects like endothelial cell loss. Future studies will evaluate how the improved precision and reproducibility of OCT-guided femtosecond cataract surgery translates into increased safety and improved refractive outcomes with various types of IOLs.
Clinical Trial: :
http://www.clinicaltrials.gov NCT00922571, NCT01069172
Keywords: cataract • laser • refractive surgery