Researchers at Bausch + Lomb recently conducted a prospective, randomized, double-masked, parallel-group, noninferiority clinical trial to compare the intraocular pressure-lowering effect of latanoprostene bunod 0.024% with timolol maleate 0.5% in subjects with open-angle glaucoma or ocular hypertension. The study’s findings demonstrate that LBN 0.024% once daily in the evening is noninferior to timolol 0.5% administered twice daily and results in significantly greater IOP lowering over three months of treatment in subjects with OAG or OHT.
The researchers looked at adults with OAG or OHT from 46 clinical sites and randomized them 2:1 to LBN instilled once daily in the evening or timolol instilled twice a day for three months. The researchers then recorded IOP at weeks two and six, and at month three. A total of 387 subjects completed the study.
The analysis of covariance showed that average IOP reduction with LBN was not only noninferior to timolol but also significantly greater than timolol at all but the first time point in this study (p≤0.025). Regarding LBN- and timolol-treated subjects, respectively, 31 percent and 18.5 percent (p=0.007) had their IOP reduced ≥25 percent from baseline, and 17.7 percent and 11.1 percent, respectively, (p=0.084) had their IOP reduced to ≤18 mm Hg over all time points/visits in this study. Ocular emergent adverse events, while uncommon, appeared more frequently in the LBN group, all of which were mild to moderate except one case of severe hyperemia.
Am J Ophthalmol 2016;168:250-259.
Medeiros F, Martin K, Peace J, Sforzolini BS, Vittitow JL, Weinreb RN.
Diagnostic Accuracy for Identifying Glaucoma in Myopes
Ruling out glaucoma in myopic eyes often poses a diagnostic challenge because of atypical optic disc morphology and visual field defects that can mimic glaucoma. This case-control, cross-sectional study determined that Bruch’s membrane opening minimum rim width is more sensitive than disc margin rim area and similar to retinal nerve fiber layer thickness for the identification of glaucoma in myopic eyes, and offers a valuable tool for diagnosing glaucoma patients with myopic optic discs.
The study looked at 56 myopic patients with glaucoma, with 74 non-glaucoma patients with myopia used as controls. Researchers recruited myopic subjects with refractive errors greater than -2 D and typical myopic optic disc morphology, with and without glaucoma, from a glaucoma clinic and a local optometry practice. The final classification of myopic glaucoma or myopic control was based on a consensus assessment by three clinicians using visual fields and optic disc photographs. The participants underwent imaging with confocal scanning laser tomography for measurement of DM rim area and with spectral domain optical coherence tomography for quantification of a BMO-based neuroretinal rim parameter, minimum rim width and RNFL thickness.
The researchers measured the sensitivity of DM-RA, BMO-MRW and RNFL thickness at a fixed specificity of 90 percent and partial area under the curves for global and sectoral parameters for specificities ≥90 percent.
The sensitivities at 90-percent specificity were 30 percent for DM-RA and 71 percent for both BMO-MRW and RNFL thickness. The pAUC was higher for the BMO-MRW compared with DM-RA (p<0.001), but similar to RNFL thickness (p>0.5). The sectoral values of BMO-MRW tended to have a higher, but not significantly higher, pAUC across all sectors compared with RNFL thickness.
The researchers claim that further studies are necessary to better evaluate the utility of sectoral analysis in myopic eyes, but that these results suggest that it might provide useful diagnostic information.
Malik R, Belliveau AC, Sharpe GP, Shuba LM.
The Degradation of Mitomycin-C Under Various Storage Methods
Because pharmacies store MMC under various conditions before ophthalmic surgical use, researchers decided to study the storage conditions’ effects on the drug. This study found similar high stabilities (96 to 98 percent) for all storage methods when MMC solutions were analyzed immediately after warming to room temperature. For MMC that had been refrigerated for two weeks or shipped on ice, sitting at room temperature for 24 hours resulted in negative slopes suggesting degradation; however, all MMC samples maintained greater than 90-percent retention.
The researchers used c18 reversed-phase high-performance liquid chromatography to determine the stability of 0.4 mg/mL MMC solutions, and liquid chromatography-electrospray ionization-mass spectrometry to identify degradation products. The conditions that this study compared were as follows: compounding and storage by refrigeration (one and two weeks); freezing (23 days); shipment on ice (one month frozen followed by one-week refrigeration); and immediately compounding dry powder. The researchers evaluated three samples for each storage method when samples reached room temperature, as well as one, four and 24 hours later, using MMC peak area as a percentage of total area detected with high-performance liquid chromatography as a measure of stability.
At time 0, there were similar stabilities for MMC (p=0.599) among all storage methods: one-week refrigerated (97.9 ±0.2 percent); dry powder (97.5 ±0.3 percent); two-week refrigerated (96.9 ±0.2 percent); 23-day frozen (96.7 ±3.1 percent); and shipment on ice (96 ±1.2 percent). However, MMC demonstrated significant degradation over a 24-hour period with two-week refrigeration (95.7 ±0.3 percent, B=-0.1 percent/h, p<0.001) and shipment on ice (93.1 ±1.8 percent, B=-0.1 percent/h, p=0.013). There were small amounts (<3.2 percent) of two degradants, cis-hydroxymitosene and trans-hydroxymitosene, across all samples.
The clinical significance of small amounts of MMC degradants is unclear.
J Glaucoma 2016;25:477-481.
Kinast RM, Akula KK, DeBarber AE, Barker GT.
Combined Trabectome and PPV for Treatment of Glaucoma and Vitreoretinal Pathology
Researchers at the Cincinnati Eye Institute studied patients who underwent combined Trabectome and pars plana vitrectomy for uncontrolled glaucoma and visually significant retinal pathology. The postoperative study looked at four patients during a one-year follow-up period. Optical coherence tomography outcomes at one year showed improvement in macular anatomy and foveal contour without cystoid macular edema.
Although the visual results and intraocular pressure reduction after the procedures didn’t reach statistical significance, the researchers say there was a trend toward improvement in both macular anatomy and glaucoma control, suggesting that further study of combined vitrectomy and Trabectome surgery may be warranted. Another possible advantage of the procedure is that a combined approach that simultaneously addresses both conditions would be advantageous to patients in terms of reduced costs and potentially faster visual recovery.
Surgeons performed the combined Trabectome MIGS procedure and 25-gauge PPV on three eyes of four patients for primary open-angle glaucoma. There were two male and two female patients with their ages ranging from 63 to 80 years.
The mean preoperative LogMAR visual acuity was 0.39 (20/49) and 12-month LogMAR visual acuity was 0.21 (20/32) (p=0.06). The average maximum preoperative IOP was 27 mmHg, and the mean preoperative IOP was 17 mmHg, measured over a period of six to 12 months before the combined surgery. The 12-month average IOP was 12.8 mmHg (p=0.07). One postop patient developed a hyphema requiring anterior chamber washout at one week. No other complications occurred. Researchers note that the limitations of this study include its small sample size and case selection bias.
Toussaint B, Petersen MR, Sisk RA, Riemann CD.