A Randomised Comparison of Two Laser Iridotomy Techniques in Patients of Primary Angle Closure Disease with Absent Iris Crypts

Purpose: Patients with absent iris crypts are the most challenging cases for performing laser peripheral iridotomy. This study was conducted on patients of primary angle closure disease belonging to this group to find out the difference in the quantum of energy and number of attempts required to achieve optimum peripheral iridotomy by sequentially using double frequency Nd:YAG and Nd:YAG laser versus Nd:YAG laser alone. Methods: Forty eyes of 40 patients of 35 years or more, with primary angle closure disease and absent iris crypts, in whom laser peripheral iridotomy (LPI) was indicated, were prospectively randomized into two groups. Patients in group one sequentially underwent double frequency Nd:YAG & Nd:YAG laser and group two underwent Nd:YAG laser alone. Follow up was done one hour, three hours, one day and one week post laser. Any rise of IOP of > 8 mmHg from base line or an absolute figure of 30 mmHg at any visit was considered significant. Post laser topical loteprednol etabonate 4 times per day for one week and pilocarpine nitrate 2% eye drops twice a day for five days were used in all cases. Statistical testing was conducted with the statistical package for the social science system (SPSS) version 17.0. Results: Group one had 3 male and 16 female patients whereas group two had 9 and 12 male and female patients respectively. Nd:YAG energy required in group one (n=19) was 48.79 ± 19.41 mJ and in group two (n=21) was 88.81 ± 37.36 mJ (p=