Analysis of energy levels for Nd : YAG laser capsulotomy in secondary cataract

Background: Formation of secondary cataract is influenced by various factor s, such as IOL material, IOL design, age,follow-up time and ocular and syst emic diseases. It has not yet been studied whether these factors have an cl inical impact on the energy used for Nd:YAG laser capsulotomy. Patients and methods: We examined 172 patients, aged 67.3+/-15.9 years, con cerning energy levels required for Nd:YAG laser capsulotomy. We analysed th e influence of age, implant duration, IOL fixation and ocular conditions on total energy and repetition rate of Nd:YAG laser capsulotomy. Sixty-nine p atients (43.7%) had no other ocular pathology (control), 24 (15.2%) glaucom a, 14 (8.9%) diabetic retinopathy, 12 (7.6%) retinitis pigmentosa, 8 (5.1%) high myopia, 7 (4.4%) triple procedure with perforating keratoplasty. Twen ty-four (15.2%) presented with Various additional ocular conditions such as pseudoexfoliation syndrome. Patients had undergone cataract surgery betwee n 1988 and 1995 with implantation of PMMA-IOLs. Results: Nd:YAG laser capsulotomies were performed an average 28.2+/-17.7 m onths postoperatively. The average total energy used was 12.7+/-9.4 mJ. Vis ual acuity (Pre-YAG) was 0.3+/-0.2. In the control group there was no corre lation between energy and implant duration or age (P>0.43). 26 patients req uired a second Nd:YAG laser capsulotomy. Patients with retinitis pigmentosa showed a significantly higher re-YAG rate than the other patient groups (P =0.00059). In eyes with sulcus fixation of the IOL, capsulotomies were perf ormed earlier and with higher energy levels than for in-the-bag fixation. Conclusions: The different ocular conditions of the anterior and posterior segment showed a different profile for Nd:YAG laser capsulotomy energy leve l and Nd:YAG laser repetition rate. Sulcus fixation of an IOL resulted in e arlier capsulotomies with higher energy levels.