JOURNAL CLUB

RECENT NOTEWORTHY STUDIES TO STIMULATE DISCUSSION AND DEBATE

■ Treatment correlations in AMD. To determine whether previous reports that both polymorphisms in the gene coding apolipoprotein E (APOE) and the location of fluid within the macula affected the outcomes of treatment for wet AMD, doctors in Australia undertook a prospective study.

A total of 186 eyes of 186 patients with subfoveal CNV due to AMD were enrolled and monitored over 12 months. All of the patients were submitted to VA measurements, OCT, and genetic testing. The patients were treated with three months of loading doses of ranibizumab (Lucentis, Genentech, South San Francisco, CA) or bevacizumab (Avastin, Genentech).

The study found that patients with an ε2 polymorphism on the APOE gene were more likely to have intraretinal fluid at baseline. After the loading doses, 48 eyes still had intraretinal fluid on OCT, with no statistically significant association between variations in APOE and fluid, although almost twice as many patients with the ε2 polymorphism had fluid, compared to patients with other polymorphisms.

Although the authors concede that larger studies are needed to determine the true relationship between the APOE gene polymorphisms and intraretinal fluid, they believe that testing for this gene could be a predictor of treatment response to anti-VEGF drugs in the future.

Wickremashinge SS, Sandhu SS, Amural-Islam FM, et al. Polymorphisms in the APOE gene and the location of retinal fluid in eyes with neovascular age-related macular degeneration. Retina. 2014;34:2367-2375.

■ DME grading. Retinal physicians in Vienna have developed a new grading system for clinically significant DME, using both OCT and fluorescein angiography, and they recently tested it in a cohort of 40 patients.

Fifty-six eyes of these patients underwent spectral-domain OCT with one of three different models, as well as FA. The images were then graded by three of the authors, using the SAVE protocol, which assesses subretinal fluid (present or not present), area (from 0 to 9 fields), vitreoretinal interface abnormalities (present or not present), and etiology (focal or nonfocal leakage, ischemia, or atrophy).

The intergrader reliability was good for three of the four criteria, with only vitreoretinal interface abnormalities showing weaker agreement. In addition, the study team was able to identify atrophic as a new etiology for DME, consisting of retinal cystoid degeneration without Müller cells.

Further studies are already under way to test the SAVE protocol in both clinical and study settings, as well as studies designed to identify correlations between SAVE grading and established visual and anatomical assessments.

Bolz M, Lammer J, Deak G, et al; Diabetic Retinopathy Research Group Vienna. SAVE: a grading protocol for clinically significant diabetic macular oedema based on optical coherence tomography and fluorescein angiography. Br J Ophthalmol. 2014;98:1612-1617.

■ ERG in macular hole. A pair of ophthalmologists recently found that cone implicit time, as measure by electroretinography, could predict visual outcomes following macular hole surgery.

Nineteen consecutive patients underwent macular hole closure surgery by pars plana vitrectomy with internal limiting membrane peeling. All of the eyes received gas tamponade, followed by at least five days of face-down positioning, followed by a series of visual function tests, including ERG, and comparison with these data to baseline measurements.

The key result was that cone 30-Hz flicker implicit time on ERG was statistically significantly prolonged presurgically in the patients, compared to their age-matched controls. This alteration in cone function persisted in these patients for up to 18 months postsurgically. Seven patients with cone 30-Hz flicker implicit times >33.5 msec had notably worse VA outcomes.

The authors believe that their study provides evidence for the theory that cones are the more sensitive type of photoreceptors to certain traumatic events. The study was the first to use ERG in this particular context.

Andréasson S, Ghosh F. Cone implicit time as a predictor of visual outcome in macular hole surgery. Graefes Arch Clin Exp Ophthalmol. 2014;252:1903-1909.

■ Treat-and-extend data. Ophthalmologists from Wills Eye Hospital in Philadelphia recently published three-year data on a treat-and-extend protocol, finding additional evidence for the efficacy of this protocol.

One hundred ninety-six eyes of 212 patients with wet AMD received intravitreal injections of either ranibizumab or bevacizumab for a period of at least one year using a treat-and-extend protocol that was extended or shortened by two-week intervals. BCVA, central retinal thickness, and number of injections were recorded.

With a mean follow-up period of 1.88 years, mean BCVA improved from 20/139 to 20/79 at one year and was maintained at between 20/64 and 20/69. Mean central retinal thickness decreased from 351 µm to between 275 and 285 µm. The mean numbers of injections were 7.6, 5.7, and 5.8 for years 1, 2, and 3, respectively.

Confident of the conclusion that the treat-and-extend protocol is safe and effective, the authors end the article with a call for head-to-head comparisons of this protocol with others, including on-label monthly dosing. RP

Rayess N, Houston SKS III, Gupta OP, Ho AC, Regillo CD. Treatment outcomes after 3 years in neovascular age-related macular degeneration using a treat-and-extend regimen. Am J Ophthalmol. 2014;159:3-8.