Patients with varying severities of age-related macular degeneration can experience a postoperative improvement in visual acuity after cataract surgery, according to the latest AREDS analysis. Researchers discovered this after evaluating 4,757 participants enrolled in the Age-Related Eye Disease Study, a prospective, multicenter, epidemiological study of the clinical course of cataract and AMD and a randomized, controlled trial of antioxidants and minerals. For the study, standardized lens and fundus photographs—performed at baseline and annual visits—were graded by a centralized reading center using standardized protocols for severity of AMD and lens opacities. History of cataract surgery was obtained every six months. Outcome was measured by reviewing the change in best-corrected visual acuity after cataract surgery compared with preoperative BCVA.

VA results were analyzed for 1,939 eyes that had cataract surgery during AREDS. The mean time from cataract surgery to measurement of postoperative BCVA was 6.9 months.
After adjustment for age at surgery, gender, type and severity of cataract, the mean change in VA at the next study visit after the cataract surgery was as follows: Eyes without AMD gained 8.4 letters of acuity (p<0.0001); eyes with mild AMD gained 6.1 letters (p<0.0001); eyes with moderate AMD gained 3.9 letters (p<0.0001); and eyes with advanced AMD gained 1.9 letters (p=0.04). The statistically significant gain in VA after cataract surgery persisted, on average, for at least 18 months.

Ophthalmology 2009;116:2093-100.

Forooghian F, Agrón E, Clemons TE, et al.

Aqueous Analysis Helps Judge Biomarkers

Aqueous samples may be useful for investigating potential involvement of molecular targets in various disease processes and for pharmacokinetic or pharmacodynamic studies, say researchers at Johns Hopkins University and the University of Maryland Medical System. In order to assess the value of sampling aqueous humor for measurement of potential molecular targets and for pharmacokinetic analysis, researchers conducted a substudy within the context of clinical trials. The study reviewed 40 patients with macular edema caused by central retinal vein occlusion or branch retinal vein occlusion, 11 patients with diabetic macular edema and eight patients with neovascular age-related macular degeneration. Assays for potential molecular targets were performed on aqueous samples from patients participating in drug studies (CRVO, BRVO and DME) or patients receiving standard care (neovascular AMD). Ranibizumab levels were measured in patients with CRVO or BRVO after the first and second injections of ranibizumab. Outcome was measured by reviewing aqueous levels of vascular endothelial growth factor, interleukin-6, IL-1beta, tumor necrosis factor-alpha and ranibizumab.

Aqueous levels of VEGF were significantly higher in patients with DME than in patients with CRVO, which proved to be significantly higher than those in patients with BRVO. Patients with NVAMD had aqueous VEGF levels in an intermediate range, significantly higher than those in patients with BRVO. One month after the second injection of ranibizumab, 27 of 39 patients with vein occlusions had no residual edema; mean aqueous levels of IL-6, IL-1beta and TNF-alpha were not greater in patients with residual edema. This provides a blueprint for definitive studies with larger cohorts.

There was no significant difference in aqueous ranibizumab levels one month after the first injection of 0.5 mg versus the injection of 0.3 mg, but one month after the second injection ranibizumab levels were shown to be significantly higher in eyes injected with 0.5 mg. There were substantial differences in levels among patients, but levels in the same patient at months one and two were shown to be highly correlated. No significant difference in aqueous ranibizumab levels was detected between phakic and pseudophakic patients who received the same dose.

Ophthalmology 2009;116:2158-64.

Campochiaro PA, Choy DF, Do DV, et al.

Bevacizumab Dosage Affects Neovascular AMD

Baseline aqueous vascular endothelial growth factor level might have a role in predicting angiographic response after bevacizumab injections, according to research at the Hong Kong Eye Hospital and the Prince of Wales Hospital in Hong Kong. Researchers reviewed 50 eyes of 50 patients with neovascular AMD, which were randomized to receive three monthly intravitreal injections of 1.25 mg (24 eyes) or 2.5 mg (26 eyes) bevacizumab. Patients were observed for six months, and BCVA, central foveal thickness, aqueous vascular endothelial growth factor, and pigment epithelial de-rived factor levels were assessed.

Both groups had significant central foveal thickness reductions at six months (p<0.001). However, six eyes (23.1 percent) in the 2.5-mg group lost three or more lines compared with none in the 1.25-mg group (p=0.023). No significant difference in BCVA, central foveal thickness or growth factors levels was found between the two groups at all visits. Eyes presenting with persistent angiographic leakage at three months had significantly higher baseline aqueous vascular endothelial growth factor levels compared with eyes without leakage (p=0.013). High baseline aqueous vascular endothelial growth factor level was the only significant factor associated with persistent leakage at
the three-month point (p=0.040).

The researchers concluded that three monthly intravitreal 1.25-mg bevacizumab injections seemed to result in better visual outcomes than 2.5-mg injections.

Retina 29:1218-1226;2009

Lai TY, Liu DT, Chan KP, et al.