Hidenobu Tanihara

Neuroprotective effects of brain-derived neurotrophic factor in eyes with NMDA-induced neuronal death

PURPOSE To determine if brain-derived neurotrophic factor (BDNF) has a neuroprotective effect against N-methyl-D-aspartate (NMDA)-induced cell death in retina. METHODS NMDA was injected into the vitreous of rat eyes. NMDA-induced neuronal death was measured by morphometric analyses on cell counts of ganglion cell layer cells and thickness of retinal layers. Also, we conducted additional experiment using retrograde labeling with a fluorescent tracer (Fluoro-Gold) for exact counting of retinal ganglion cells (RGCs). In addition, intravitreal glutamate levels were measured with the use of a high-performance liquid chromatography (HPLC) system. RESULTS Morphometric analysis of retinal damage in NMDA-injected eyes showed that BDNF could protect inner retinal cells from glutamate receptor-mediated neuronal death. Also, counts of RGCs labeled with a fluorescent tracer showed that BDNF could protect RGCs from glutamate receptor-mediated neuronal death. Furthermore, measurements of intravitreal glutamate levels indicated an increase in this excitatory amino acid in the vitreous after NMDA injection. CONCLUSIONS Exogenous BDNF can protect inner retinal cells (possible RGCs and amacrine cells) from NMDA-induced neuronal death. However, increased intravitreal glutamate levels in response to NMDA-mediated neurotoxicity may augment retinal degeneration.

Surgical results and complications of goniosynechialysis

Goniosynechialysis (GSL) was performed in 70 eyes with primary angle-closure glaucoma in which the intraocular pressure (IOP) could not be controlled with laser or surgical iridectomy. Following GSL, the IOP was maintained at below 20 mmHg, with and without eye drops, in 34 (87%) of 39 aphakic eyes and in 13 (42%) of 31 phakic eyes. In 8 of 10 eyes, all of which were phakic and the first GSL procedure was not effective, IOP could be controlled by a second GSL procedure combined with lens extraction. Life-table analysis showed a significant difference between the probable success rate, after 5 years, between the phakic and aphakic groups. Postoperative tonographic C values showed improvement in outflow facility. However, frequently encountered complications were exudation of fibrin and minor hemorrhage. Our results suggest that a combination of GSL and extraction of the lens may be necessary to control refractory angle-closure glaucoma.

Novel Mutations in the Myocilin Gene in Japanese Glaucoma Patients

Myocilin is a gene responsible for juvenile onset primary open angle glaucoma (POAG) mapped as the GLC1A locus and, many mutations have been reported worldwide. Some mutations were found not only in patients with juvenile onset POAG, but also in patients with late onset POAG and in patients with normal tension glaucoma. To investigate the mutation prevalence in Japan, we performed a mutation analysis in 140 unrelated Japanese patients. We have identified the 10 sequence variants, of which four were highly probable for disease‐causing mutations (Arg46ter, Arg158Gln, Ile360Asn, and Ala363Thr), and six polymorphisms (Gln19His, Arg76Lys, Asp208Glu, Val439Val, Arg470His, and Ala488Ala). Thus, myocilin mutations were found at the rate of 4/140 (2.9%) probands, similar to previous reports with other ethnic populations. Hum Mutat 16:270, 2000.

Argon-laser gonioplasty following goniosynechialysis

We performed laser gonioplasty following goniosynechialysis on 12 eyes that exhibited a very narrow angle. In these cases, angle closure had recurred postoperatively, although gonioscopy carried out at the time of goniosynechialysis revealed opening of the trabecular meshwork. The use of laser gonioplasty following goniosynechialysis was most effective in flattening the configuration of the iris and opening the iridocorneal angle. The induced alteration of the structure of the iris remained unchanged in all cases throughout the follow-up period, and intraocular pressure remained below 20 mmHg in 9 of the 12 eyes. It thus appears that a combination of goniosynechialysis and laser gonioplasty may be effective in the management of refractory angle-closure glaucoma in the presence of an extremely narrow angle.

Long-term results of non-filtering surgery for the treatment of primary angle-closure glaucoma

Abstract• Background: We previously reported the effectiveness of goniosynechialysis and trabeculotomy ab externo for adult-onset glaucoma. In this study, we performed non-filtering surgery on patients with primary angle-closure glaucoma and studied the long-term outcome of this treatment. • Methods: Included in this study were 35 eyes of 25 patients with primary angle-closure glaucoma, each of which had an intraocular pressure greater than 20 mmHg with maximal tolerated antiglaucoma medication, even after laser iridotomy or surgical iridectomy. Of these 35 eyes, 22 underwent trabeculotomy and 13 underwent goniosynechialysis. All patients were followed up for at least 18 months. • Results: In 21 (95%) of 22 eyes after trabeculotomy, and in 12 (92%) of 13 eyes after goniosynechialysis, intraocular pressures were well controlled at or below 21 mmHg at the final examination. However, in two of the 21 eyes in which trabeculotomy was a success, and in four of the 12 eyes in which goniosynechialysis was successful, the procedure had to be repeated before adequate control of pressure was achieved. • Conclusion: Our results show that intraocular pressure in most cases of primary angle-closure glaucoma can be controlled by restructuring of the physiologic aqueous outflow route by means of goniosynechialysis or trabeculotomy, and that filtering surgery is not necessary.

External trabeculotomy for the treatment of steroid-induced glaucoma.

Purpose: To investigate the effect of external trabeculotomy on eyes with steroid‐induced glaucoma. Methods: We retrospectively analyzed the surgical results of 14 eyes of seven patients that underwent trabeculotomy for the first surgical procedure. All patients had the history of receiving topical or systemic corticosteroids before the rise of intraocular pressure had been noted. Results: After an average follow‐up of 60.6 ± 33.5 months, in all of the 14 eyes, intraocular pressure was well controlled below or equal to 21 mm Hg at the final examinations. Conclusions: Surgical results of external trabeculotomy remain effective for a long time. It has been shown that the trabeculotomy can be a useful and effective surgical treatment of patients with steroid‐induced glaucoma.

Secondary glaucoma associated with crystalline lens subluxation

Purpose: To elucidate the clinical characteristics of secondary glaucoma associated with subluxation of the crystalline lens. Setting: Department of Ophthalmology and Visual Sciences, Kyoto University Graduate School of Medicine, Kyoto, and Department of Ophthalmology, Tenri Hospital, Nara, Japan. Methods: This retrospective study comprised 14 eyes of 13 patients with uncontrolled intraocular pressure (IOP) and lens subluxation. The subluxated lens was extracted through surgery. Results: Angle closure caused by the subluxated lens was complicated in 3 eyes. In the remaining 11 eyes, uncontrolled IOP elevation was found despite the presence of deep anterior chambers and wide open angles. A mean of 14.1 months ± 13.7 (SD) after cataract surgery, IOP was well controlled (lower than 21 mm Hg) in all 14 eyes. Mean IOP was 15.4 ± 2.2 mm Hg at the final examination. Complications included transient vitreous hemorrhage in 5 eyes, choroidal detachment in 2 eyes, and retinal tears in 1 eye. Conclusion: Lens extraction surgery was effective in controlling IOP in eyes with secondary glaucoma associated with lens subluxation.