Ultrasound biomicroscopy and intraocular-pressure-lowering mechanisms of deep sclerectomy with reticulated hyaluronic acid implant.

PURPOSE: To evaluate the anatomic characteristics and intraocular pressure (IOP) lowering mechanisms of deep sclerectomy with reticulated hyaluronic acid implant (DS with RHAI) using ultrasound biomicroscopy (UBM). SETTING: Eye Clinic, Department of Neurological and Vision Sciences, University of Verona, Verona, Italy. METHODS: Thirty patients with primary open-angle glaucoma not controlled by medical therapy had DS with RHAI in 1 eye. A complete ocular examination and UBM study were performed 1, 3, 6, and 12 months postoperatively and thereafter at 6 month intervals. Eleven parameters were evaluated, the most important of which were IOP, surgical success in lowering IOP to 21 mm Hg or less with or without additional medical therapy, UBM appearance of the site of DS with RHAI, size of the decompression space, presence of a filtering bleb and supraciliary hypoechoic area, and scleral reflectivity around the decompression space. RESULTS: After a mean follow-up of 11.4 months +/- 4.7 (SD), the mean percentage reduction in IOP compared to preoperatively was 38% (from 26 +/- 4.5 mm Hg to 16.2 +/- 3.8 mm Hg; P =.0001). Twenty-four patients (80%) had an IOP less than 21 mm Hg; however, 7 of these eyes (23%) required additional IOP-lowering medical therapy. The operation failed in 6 patients (20%) despite additional therapy. Ultrasound biomicroscopy revealed a reduction in the size of the decompression space from 6 months postoperatively and its disappearance in 2 cases. The difference in size at the last follow-up and at 1 month postoperatively (maximum length 2.41 +/- 1.02 mm versus 3.53 +/- 0.51 mm) was significant (P =.0001). At the last examination, a filtering bleb was present in 18 patients (60%), a supraciliary hypoechoic area in 18 (60%), and hyporeflectivity of the scleral tissue around the decompression space in 14 (47%). These 3 UBM characteristics were detected singly and in various combinations. The simultaneous presence of all 3 characteristics in the same eye correlated significantly with a higher surgical success rate (P =.004). CONCLUSIONS: Ultrasound biomicroscopy showed that filtering bleb formation was frequent in eyes having DS with RHAI but that it was not the only surgically induced IOP-lowering mechanism. Increased uveoscleral and transscleral filtration may be equally important.

Ultrasound biomicroscopy and corneal endothelium in Nd:YAG-laser iridotomy.

BACKGROUND AND OBJECTIVE: Thirty eyes affected by angle-closure glaucoma that had undergone YAG-laser iridotomy were studied to evaluate variations of central anterior chamber depth, width of the angle, and loss of endothelial cells after laser treatment. PATIENTS AND METHODS: These parameters were determined before and after iridotomy: endothelial cell count using a "non-contact" specular biomicroscope, and anterior 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 UBM, after laser treatment. RESULTS: Results confirmed that, after iridotomy, there is not a significant variation in the central depth of the anterior chamber: it goes from 2.02 mm pre-laser to 2.07 +/- 0.38 mm 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 endothelial cell count was 55.8 +/- 4.08 cells per linear millimeter before laser treatment and 47.01 +/- 5.39 cells per linear millimeter afterward (P <.001). CONCLUSION: This study confirms that YAG-laser iridotomy leads to a reduction in the average endothelial cell density. The loss of these cells is inversely proportional to the distance of the iridotomy from the endothelium and the scleral spur.

Subconjunctival THC:YAG laser sclerostomy for the treatment of glaucoma: preliminary data.

A subconjunctival thermal sclerostomy was performed using the recently developed THC:YAG laser in 33 eyes with a variety of glaucomas in which, in most cases, neither medical therapy nor previous procedures had been successful in controlling intraocular pressure (IOP). The mean preoperative IOP was 27.5 +/- 7.5 mm Hg with maximum medication. The laser procedure was quick and easy, with minimal manipulation of tissues; complications were clinically insignificant. The day after the operation, 23 eyes had an IOP less than 18 mm Hg; in the other 10, it was unchanged. In most of the eyes, an obvious filtering bleb developed at the site of the sclerostomy. The internal opening of the sclerostomy was visible on gonioscopy, except in five cases, in which it was plugged by a fold of the iris root. One year after the operation, IOP was controlled in three eyes without medication and in 18 with medication. IOP remained uncontrolled in the remaining 12 eyes.