ULTRASOUND BIOMICROSCOPY AND CORNEAL ENDOTHELIUM IN ND-YAG-LASER IRIDOTOMY

BACKGROUND AND OBJECTIVE: Thirty eyes affected by angle-closure glauco ma that had undergone YAG-laser iridotomy were studied to evaluate var iations of central anterior chamber depth, width of the angle, and los s of endothelial cells after laser treatment. PATIENTS AND METHODS: Th ese parameters were determined before and after iridotomy: endothelial cell count using a ''non-contact'' specular biomicroscope, and anteri or chamber depth and angle width using ultrasound biomicroscopy (UBM). The width of the iridotomy and the distance of the iridotomy from the scleral spur and from the corneal endothelium were also measured by U BM, after laser treatment. RESULTS: Results confirmed that, after irid otomy, there is nor: a significant variation in the central depth of t he anterior chamber: it goes from 2.02 mm pre-laser to 2.07 +/- 0.38 m m post-laser. There is, however, a statistically significant increase in the angle (P < .001), which goes from 10.69 +/- 8.88 degrees (0.109 +/- 0.07 mm) to 21.03 +/- 11.28 degrees (0.183 +/- 0.09 mm). The mean dimension of the iridotomies was 0.46 +/- 0.13 mm. The mean endotheli al cell count was 55.8 +/- 4.08 cells per linear millimeter before las er treatment and 47.01 +/- 5.33 cells per linear millimeter afterward (P < .001). CONCLUSION: This study confirms that YAG-laser iridotomy l eads to a reduction in the average endothelial cell density. The loss of these cells is inversely proportional to the distance of the iridot omy from the endothelium and the scleral spur.