Risk Factors for the Progression of Corneal Endothelial Decompensation After Laser Iridotomy

Abstract

Abstract: : Purpose: The purposes of this study are 1) to examine the frequency of the development of bullous keratopathy (BK) after laser iridotomy (LI) for angle–closure glaucoma (ACG) and 2) to evaluate the longitudinal decrease in the corneal endothelial cell density(CD) in patients who had undergone LI. Methods: First, the frequency of the development of BK after LI was calculated by retrospectively reviewing the records of 30 eyes of 27 acute ACG (AACG) patients who were treated with LI (AACG group) and 159 eyes of 95 patients with narrow angle, who had undergone prophylactic LI (narrow angle group). Eyes with a history of other surgical interventions were excluded from the study. Next, we recruited 38 eyes of 24 patients, who were regularly followed–up at our institution over two years after LI (12 eyes of 10 patients in the AACG group and 26 eyes of 19 patients in the narrow angle group) to longitudinally evaluate the CD by non–contact specular microscope and to determine the relationship between the CD and total amount of laser energy. . Results: All patients who developed BK received LI before 1998. The ratio of BK development was 5/30 (16.7%) in the narrow angle group and 29/159 (18.2%) in the the AACG group, which was not statistically significantly different (p=0.6). In 38 eyes with regular observation over two years after LI, the total amount of laser energy in AACG group (7.4±12.3J) was significantly higher than in the narrow angle group(2.0±1.3J)(p=0.04). In 26 eyes of the narrow angle group with regular observation CD was not reduced significantly (p=0.39). In 4 eyes of AACG group had 865±382 cells/mm² (55.2%loss) ,in 8 eyes had 2840 ±205 cells/mm² (0.25%loss) at final visit. The former received substantially higher laser energy (17.95±18.27J) than the latter (2.13±1.13J)(p<0.01). Conclusions: Since overall frequency of BK development was equivalent between AACG and narrow angle groups despite the significantly higher total energy received in the latter, development of BK may require the additional factors inherent to individuals other than AACG episode and laser energy amount.

Keywords: cornea: endothelium • cornea: clinical science • laser