Is post-trabeculectomy hypotony a risk factor for subsequent failure? A case control study

BACKGROUND: Ocular hypotony results in an increased break down of the blood-aqueous barrier and an increase in inflammatory mediator release. We postulate that this release may lead to an increased risk of trabeculectomy failure through increased bleb scarring. This study was designed to try to address the question if hypotony within one month of trabeculectomy for Primary Open Angle Glaucoma (POAG), is a risk factor for future failure of the filter. METHODS: We performed a retrospective, case notes review, of patients who underwent trabeculectomy for POAG between Jan 1995 and Jan 1996 at our hospital. We identified those with postoperative hypotony within 1 month of surgery. Hypotony was defined as an intraocular pressure (IOP) < 8 mmHg or an IOP of less than 10 mmHg with choroidal detachment or a shallow anterior chamber. We compared the survival times of the surgery in this group with a control group (who did not suffer hypotony as described above), over a 5 year period. Failure of trabeculectomy was defined as IOP > 21 mmHg, or commencement of topical antihypertensives or repeat surgery. RESULTS: 97 cases matched our inclusion criteria, of these 38 (39%) experienced hypotony within 1 month of surgery. We compared the survival times in those patients who developed hypotony with those who did not using the log-rank test. This data provided evidence of a difference (P = 0.0492) with patients in the hypotony group failing more rapidly than the control group. CONCLUSION: Early post-trabeculectomy hypotony (within 1 month) is associated with reduced survival time of blebs

Comparison of Krypton and Argon Laser Photocoagulation: Results of Simulated Clinical Treatment of Primate Retina

• We compared the clinical and histological effects of argon blue-green laser (ABGL), argon green laser (AGL), and krypton red laser (KRL) photocoagulation on the primate retina. Burns were produced in juxtafoveal and papillomacular bundle and in nonmacular areas in a manner simulating treatment of a choroidal neovascular membrane (NVM). In the juxtafoveal and papillomacular bundle areas, ABGL photocoagulation caused extensive inner retinal damage while KRL photocoagulation spared inner retinal structures. The effects of AGL photocoagulation in the fovea were intermediate in extent between KRL and ABGL photocoagulation. Axonal transport studies also showed differential effects of these wavelengths on retinal ganglion cell function. Nonmacular effects were similar for all three modalities. These results suggest that the krypton red wavelength may be more suitable than the argon green or argon blue-green wavelengths in treating choroidal NVMs near the fovea

Cell Proliferation After Laser Photocoagulation in Primate Retina: An Autoradiographic Study

• Argon blue-green laser and krypton red laser (KRL) photocoagulation were applied to primate retinas at intervals ranging from two to 23 days before the animals were killed. An injection of tritiated thymidine was given intravitreally three days before death. Argon bluegreen laser photocoagulation induced cell proliferation in the retina and retinal pigment epithelium seven days after treatment, with quiescence at 23 days. Krypton red laser photocoagulation induced similar cell proliferation not only in the retina and retinal pigment epithelium but also around choroidal vessels and in the stroma of the choroid. Peak thymidine uptake occurred seven days after KRL treatment. There was less uptake at two and 11 days and no uptake at 23 days. Thymidine uptake in the retina and choroid also was detected with low levels of KRL treatment. True cell hyperplasia (cell division) occurred after laser treatment; only KRL treatment induced cellular reaction in the choroid

Combined use of SEM-EDS, OM and XRD for the characterization of corrosion products grown on silver roman coins

In the framework of the PROMET project (European Commission contract No. 509126) aimed to develop new analytical techniques and materials for monitoring and protecting metal artefacts and monuments from the Mediterranean region, the corrosion products grown on silver Roman coins during archaeological burial is studied by means of scanning electron microscopy combined with energy dispersive spectrometry (SEM-EDS), X-ray diffraction (XRD) and optical microscopy (OM) technique