Peter T. Chang

Effects of elevated intraocular pressure on mouse retinal ganglion cells

We developed and characterized a mouse model of elevated intraocular pressure (IOP) to investigate the underlying cellular and genetic mechanisms of retinal ganglion cell (RGC) death. IOP was unilaterally increased in C57BL/6J mice by photocoagulation of the episcleral and limbal veins. IOP was measured using an indentation tonometer. RGC survival was measured by retrograde labeling using DiI applied to the superior colliculous. The mechanism of RGC death was investigated using TUNEL staining, immunostaining for cleaved caspase-3, and Western blot for Bcl-2 and Bax expression. RT-PCR was used to measure changes in Bcl-2, Bax, Bad, Bak, P53, ICE and Fas. Mean IOP was increased in the treated eyes from 13+/-1.8 to 20.0+/-2.8 mmHg at four weeks and 17+/-2.2 mmHg at eight weeks. RGC loss was 15.6+/-3.4% at two weeks and 27.3+/-4.5% at four weeks after laser photocoagulation. TUNEL staining and caspase-3 positive cells were increased in the ganglion cell layer (GCL) in the treated eyes and seldom found in the control eyes. Bcl-2 expression in control group was higher than in the experimental group, while Bax expression in the control group was less than in experimental group. This mouse model resulted in a consistent, sustained increase in IOP with a reduction in the number of RGCs in the treated eye. The RGCs in eyes with elevated IOP were TUNEL-positive, with increased caspase-3 and decreased Bcl-2, consistent with apoptosis as the mechanism of neuronal cell death.

Outcomes of surgical bleb revision for late-onset bleb leaks after trabeculectomy.

PurposeTo describe the outcome of surgical bleb revision for late-onset bleb leaks after trabeculectomy. Patients and MethodsAppropriate cases were identified. Qualified and complete success required intraocular pressure of 21 mm Hg or less with and without glaucoma medication use, respectively. Bleb survival was determined using Kaplan-Meier survival analysis, and overall success rate was defined as qualified success at last follow-up. Preoperative and postoperative ocular parameters were compared using the signed-rank test. Age, sex, ethnicity, time between leak and revision, and surgeon type (attending vs. surgeons in training) were entered into a logistic regression analysis to assess the impact on surgical outcome. ResultsSeventy-eight eyes of 75 patients were included. The overall rate of successful bleb revision was 77%, and qualified and complete success at 24 months was 71% and 34%, respectively. Postoperative complications included early and late bleb leaks in 6% and 9% of the eyes, respectively; bleb-related infections in 4% of the eyes; and the need for additional glaucoma surgery in 10% of the eyes. There was no difference in preoperative and postoperative visual acuity (P=0.34) but there was an increase in intraocular pressure (P<0.0001) and the number of medications used (P<0.0001). The number of eyes that did not require glaucoma medication decreased (P=0.002). None of the variables examined had a significant impact on successful surgical outcome. ConclusionBleb revision showed a high success rate. About two-thirds of eyes required medication, 10% of eyes required additional glaucoma surgery, and there was a low risk for bleb-related infection following bleb revision.

Rapidly progressing glaucoma associated with monoclonal gammopathy.

A 63 year old woman with surgically controlled primary open-angle glaucoma developed sudden visual field deterioration and subjective visual loss despite stable intraocular pressure in both eyes. An extensive systemic workup was performed which revealed a diagnosis of monoclonal gammopathy of undetermined significance. Further work-up should be considered when the extent of a patient’s vision changes is not consistent with a known preexisting disease such as glaucoma.

Strenotrophomonas Maltophilia-related Chronic Dacryocystitis

Dacryocystitis related to Stenotrophomonas maltophilia is rare. We describe a case of Strenotrophomonas maltophilia-related chronic dacryocystitis with associated coagulase-negative Staphylococcus. Following external dacryocystorhinostomy without intraoperative or postoperative antibiotics, her discharge and lacrimal sac fullness resolved.

Intraocular Pressure Control Among Patients Transitioned From Latanoprost to Travoprost at a Veterans Affairs Medical Center Eye Clinic

PURPOSE To evaluate intraocular pressure (IOP) control and the ocular adverse effects resulting from a large-scale transition from latanoprost to travoprost among patients at a Veterans Affairs Medical Center (VAMC) Eye Clinic. METHODS Retrospective chart review of patients transitioned from latanoprost to travoprost after a revision of the drug formulary used by the VAMC in Houston, Texas. IOP control after changing medications and the incidence of ocular adverse effects attributed to travoprost were the main outcomes measured. For patients who were using IOP-lowering medications bilaterally, the worse eye was used for all IOP analyses. Long-term retention in IOP control plus a cost-saving analysis were presented as a secondary assessment. RESULTS Five hundred ninety-nine (599) patients with 1,041 treated eyes were evaluated. Mean IOP was 15.86 +/- 4.15 mmHg among patients using latanoprost prior to the prostaglandin analog transition. After transitioning to travoprost, the mean IOP was 15.78 +/- 4.38 mmHg. The mean within-eye change in IOP in the worse eye when transitioned from latanoprost to travoprost was -0.07 +/- 3.27 mmHg (P = 0.5914). Twenty-four (24) patients (4%) experienced an ocular adverse effect while using travoprost. In the long-term retention analysis at 1 year, mean change in IOP from the time of the original change to travoprost was +0.21 +/- 3.71 mmHg (P = 0.2683). CONCLUSIONS The large-scale transition from latanoprost to travoprost maintained long-term IOP control. Only a small percentage of clinic patients experienced mild ocular adverse effects after being transitioned to the new prostaglandin analog.