THE LATEST PUBLISHED RESEARCH

Exercise May Reduce Risk of Developing Exudative AMD
An analysis involving 3,874 participants in the Beaver Dam Eye Study suggested that regular exercise might protect against the development of exudative age-related macular degeneration (AMD). At baseline, participants recorded their level of physical activity on a questionnaire. Later, through four examination phases at five-year intervals, researchers determined the 15-year cumulative incidence of AMD. After controlling for age, sex, history of arthritis, systolic blood pressure, body mass index, smoking and education, physical activity was not related to the incidence of early AMD or pure geographic atrophy. However, participants who reported physical activity three or more times per week were less likely to develop exudative AMD (odds ratio 0.3, 95 percent confidence interval 0.1 to 0.7) than those who did not. After multivariate adjustment, increased categories of number of blocks walked per day decreased the risk of developing exudative AMD (odds ratio 0.7, 95 percent confidence interval 0.6 to 0.97).

Source: Knudtson MD, Klein R, Klein BEK. Physical activity and the 15-year cumulative incidence of age-related macular degeneration: the Beaver Dam Eye Study. Br J Ophthalmol 2006;90:1461-1463.

One-Year Randomized Study Evaluates PDT Plus Triamcinolone for AMD
In a prospective, randomized study, photodynamic therapy (PDT) with verteporfin (Visudyne) combined with intravitreal triamcinolone produced greater improvement in mean visual acuity, lesion size and foveal thickness than PDT alone in patients with predominantly classic subfoveal choroidal neovascularization (CNV). Thirty patients received PDT alone and 31 patients received PDT followed by 11 mg of triamcinolone. Patients were retreated every three months if fluorescein angiography showed leakage.

At one year, visual acuity was significantly better (p=0.001) in the combination treatment group. Seventy-four percent of those patients lost fewer than 15 lines compared with 61 percent of the patients treated with PDT alone (p=0.78). Decreases in lesion size (p=0.001) and foveal thickness (p=0.03) were greater with the combination treatment.

The rate of retreatment was lower in the combination group (p=0.04). Glaucoma developed in 25.8 percent of those patients, and cataracts progressed in 32 percent.

Sources: Arias L, Garcia-Arumi J, Ramon JM, et al. Photodynamic therapy with intravitreal triamcinolone in predominantly classic choroidal neovascularization: one-year results of a randomized study. Ophthalmology 2006;113:2243-2250.

Chromosome 6q Locus Linked to AMD Susceptibility
A genome scan on a cohort of families with AMD confirmed previously discovered susceptibility loci at 1q, 3p, 9q, and 10q and identified a new locus at chromosome 6q (two-point heterogeneity logarithm of odds 3.70 at 6q25.2). The current scan widened a 2003 genome-wide linkage analysis of 70 pedigrees, using 556 microsatellite markers, ascertaining members of 51 new families, and expanding many of the original pedigrees. In addition, parametric and nonparametric linkage analyses were performed with a denser map of markers, and the sample was stratified by age and phenotype at ascertainment. The two major phenotypes of advanced disease used in stratification were choroidal neovascularization and geographic atrophy.

Source: Barral S, Francis PJ, Schultz DW, et al. Expanded genome scan in extended families with age-related macular degeneration. Invest Ophthalmol Vis Sci 2006;47:5453-5459.

Study Tests Safety of Lutein Supplementation
Results of a recent study indicate that elderly individuals with and without AMD can take up to 10 mg per day of lutein for six months with no apparent toxicity or side effects. Forty-five subjects received daily supplements of lutein containing 5% zeaxanthin (at doses of 2.5, 5.0, and 10 mg) for six months and were followed for another six months. Blood was collected at various intervals and serum levels of lutein, zeaxanthin and their metabolites were quantified by high-performance liquid chromatography.

After six months of supplementation with 10 mg of lutein, the mean serum concentration level of lutein increased from 210 to 1,000 nM/L (p<0.0001), and the mean serum concentration of zeaxanthin increased from 56 to 95 nM/L (p<0.0001). Similarly, the mean serum concentration of carotenoid metabolites increased (p<0.0001), and then gradually declined over the following six months.

Source: Khachik F, de Moura FF, Chew EY, et al. The effect of lutein and zeaxanthin supplementation on metabolites of these carotenoids in the serum of persons aged 60 or older. Invest Ophthalmol Vis Sci 2006;47:5234-5242.

Triple Therapy for CNV Improves Mean VA
A combination of high-dose intravitreal triamcinolone acetonide, PDT and intravitreal pegaptanib sodium improved mean visual acuity in a group of patients with CNV, especially when used as first-line therapy. The retrospective, interventional case series study involved 22 eyes of 16 patients. Thirteen eyes had been treated previously with high-dose triamcinolone and PDT, and nine eyes were newly diagnosed. All eyes were treated with 10 mg of triamcinolone followed by PDT and pegaptanib separated by a two-week interval.

A combination of intravitreal triamcinolone, PDT and intravitreal pegaptanib sodium improved mean visual acuity and macular thickness in a group of patients with CNV, as illustrated by this patient's OCT scans. (Images courtesy of Juner Colina, MD)

Six-month results showed that mean visual acuity improved by 2.2 lines in the newly diagnosed group (p=.013) and by 0.7 lines in the previously treated group (p=0.55). Change in mean macular thickness before and after treatment was statistically significant in both groups.

Source: Liggett PE, Colina J, Chaudhry NA, et al. Triple therapy of intravitreal triamcinolone, photodynamic therapy, and pegaptanib sodium for choroidal neovascularization. Am J Ophthalmol 2006;42:1072-1074.

Anti-VEGF Agent Effective against DME
To test the role of vascular endothelial growth factor (VEGF) in diabetic macular edema (DME), 10 patients with chronic DME received 0.5-mg intravitreal injections of ranibizumab (Lucentis) at baseline and one, two, four and six months in a nonrandomized clinical study.

Left: Before this study patient’s treatment with ranibizumab for severe, chronic diabetic macular edema, fluorescein angiography (FA) showed extensive pooling of dye in the macula. Optical coherence tomography (OCT) showed marked thickening and cystic change in the fovea, and visual acuity was 20/63 (31 ETDRS letters). Right: At month six, after five intravitreal injections of 0.5 mg of ranibizumab, FA showed no collection of dye in the macula, and OCT showed resolution of thickening and cystic change and return of a foveal pit. Visual acuity improved to 20/32 (45 letters). (Images courtesy of Peter Campochiaro, MD.)

At seven months (one month after the final injection), mean foveal thickness decreased from 503 µm to 257 µm, an 85 percent decrease in excess foveal thickness compared with baseline (p=.005). Mean macular volume changed from 9.22 mm³ to 7.47 mm³, a 77-percent decrease in excess macular volume compared with baseline (p=.009). Mean visual acuity changed from 28.1 ETDRS letters to 40.4 letters, an improvement of 12.3 letters (p=.005). The injections were well-tolerated; no ocular or systemic adverse events occurred.

Authors of the study paper wrote that the results show that VEGF is an important target of therapy for DME and that a randomized, controlled trial is needed to test long-term benefits.

Source: Nguyen QD, Tatlipinar S, Shah SM, et al. Vascular endothelial growth factor is a critical stimulus for diabetic macular edema. Am J Ophthalmol 2006;142:961-969.