RECENT NOTEWORTHY STUDIES TO STIMULATE DISCUSSION AND DEBATE
■ Sunlight and AMD. In an attempt to help settle the dispute over whether sunlight exposure is a risk factor for AMD, retinal physicians in China conducted a literature review and meta-analysis to determine whether the relationship exists.
Of 14 articles the authors reviewed, 12 identified sunlight as a risk for AMD, six significantly. However, geographic degree of latitude did not have a significant effect on the risk of AMD.
However, in an unexpected finding, the study team noted that although sunlight appears to be a significant risk factor for AMD, the odds ratio decreases as gross domestic product increases, indicating the impact of better health-care systems.
Sui GY, Liu GC, Liu GY, et al. Is sunlight exposure a risk factor for age-related macular degeneration? A systematic review and meta-analysis. Br J Ophthalmol. 2013;97:389-394.
■ AMD and DR classification. Ophthalmologists and economists collaborating across several academic medical centers investigated the 10-year incidence of wet and dry AMD based on DR classification among Medicare beneficiaries.
Examining the Medicare data for cases of diabetes and of both proliferative (Figure) and nonproliferative DR between 1995 and 2005 (to control for the use of anti-VEGF drugs), they found that nonproliferative DR was associated with a significantly higher risk of both wet and dry AMD.
Meanwhile, PDR was associated only with a higher risk of wet AMD, although no higher or lower than the risk with nonproliferative DR.
Hahn P, Acquah K, Cousins SW, Lee PP, Sloan FA. Ten-year incidence of age-related macular degeneration according to diabetic retinopathy classification among Medicare beneficiaries. Retina. 2013;33:911-919.
■ Small-gauge surgery and IOP. Sutureless 23-gauge vitrectomy causes a drop in IOP, and to determine what factors are involved, scientists in France examined several of these factors, including incision architecture, as assessed by OCT.
In a prospective study, the wounds of 43 patients were imaged the day after their surgeries. Multivariate logistic regression analysis showed that only two variables measured, duration of surgery and loss of wound apposition, were significant risk factors for significant decrease in IOP.
Importantly, one factor not affecting the drop in IOP was the use or not of gas tamponade, a topic over which much controversy has been generated.
Tahiri Joutei Hassani R, El Sanharawi M, Adam R, Monin C, Dupont-Monod S, Baudouin C. Influence of sutureless 23-gauge sclerotomy architecture on postoperative intraocular pressure decrease: results of a multivariate analysis Graefes Arch Clin Exp Ophthalmol. 2013;251:1285-1292.
■ Diagnostics of myopic CNV. In a retrospective, observational case series, doctors in Paris analyzed the ability of fluorescein angiography and SD-OCT to diagnose CNV associated with high myopia.
Ninety eyes of 73 patients were enrolled, and in 82% of cases, CNV was indicated on FA vs only 48.6% of cases indicated by SD-OCT. A lack of agreement regarding signs of CNV between the two modalities was noted.
Besides recommending FA to diagnose suspected CNV in high myopes, the authors noted a relationship they found between myopic CNV and AMD in older patients.
Leveziel N, Caillaux V, Bastuji-Garin S, Zmuda M, Souied EH. Angiographic and optical coherence tomography characteristics of recent myopic choroidal neovascularization. Am J Ophthalmol. 2013;155:913-919.
■ Combo therapy for diffuse DME. To compare the safety and efficacy of two forms of combination therapy for diffuse DME, a surgeon in Egypt conducted a randomized, controlled trial of 34 eyes from 34 patients, divided into two groups of 17.
Figure. Two images of severe proliferative diabetic retinopathy.
IMAGE ADAPTED FROM AREVALO JF, SANCHEZ JG, LASAVE AF, ET AL. INTRAVITREAL BEVACIZUMAB (AVASTIN) FOR DIABETIC RETINOPATHY: THE 2010 GLADAOF LECTURE. J OPHTHALMOL. 2011;584238, COURTESY OF HINDAWI PUBLISHING CORP.
While both groups of patients were treated with intravitreal Avastin and triamcinolone, one group received pars plana vitrectomy, while the other received macular grid laser photocoagulation.
Mean BCVA was better in the group receiving vitrectomy at one and three months but worse by one year. Similarly, while mean foveal thickness was better in the vitrectomy group earlier in follow-up, it was eventually better in the laser group.
The author concluded that, within the limits of his small study, the data favored the more available and less expensive treatment with laser.
Saeed AM. Combined vitrectomy and intravitreal injection versus combined laser and injection for treatment of intractable diffuse diabetic macular edema. Clin Ophthalmol. 2013;7:283-297.