Newly published results from the Comparison of Age-related Macular Degeneration Treatment Trials show that sustained visual acuity loss was relatively rare in CATT participants. While the risk was 3 percent higher among eyes treated with bevacizumab, the development of foveal scar, pigmentary abnormalities or geographic atrophy contributed to most of the sustained visual acuity loss.
Participants in the CATT clinical trial were randomized to treatment with ranibizumab or bevacizumab and to two years of monthly or p.r.n. injections, or monthly injections for one year and p.r.n. injections for the following year. Within this group, 1,030 participants were selected for a cohort study to determine the incidence, characteristics, causes and baseline predictors of sustained visual acuity loss. Sustained visual acuity loss was defined as loss of 15 or more letters from baseline at weeks 88 and 104.
Sixty-one eyes (5.9 percent) developed sustained visual acuity loss in two years. Within this group, visual acuity decreased gradually over time, with a mean decrease of two letters from baseline at four weeks, 19 letters at one year, and 33 letters at two years. At two years, eyes with sustained visual acuity loss had more scarring (60 percent vs. 41.4 percent, p=0.007), more geographic atrophy (31.6 percent vs. 20.7 percent, p=0.004), larger lesions (16 vs. 8 mm2, p<0.001) and higher proportions of: intraretinal fluid (82.5 percent vs. 51 percent, p<0.001); subretinal hyperreflective material (84.5 percent vs. 44.2 percent, p<0.001); retinal thinning (43.3 percent vs. 23 percent, p<0.001); and thickening (20 percent vs. 12.1 percent, p<0.001). The likely causes of sustained visual acuity loss include foveal scarring (44.3 percent), pigmentary abnormalities (27.9 percent) and foveal GA (11.5 percent). Baseline factors independently associated with a higher incidence of sustained visual acuity loss were the presence of nonfoveal GA (odds ratio: 2.86; 95 percent confidence interval, 1.35 to 6.08; p=0.006); larger area of choroidal neovascularization (OR for a >4-disc area vs. ≤1-disc area: 3.91; 95 percent confidence interval, 1.7 to 9.03; p=0.007); and bevacizumab treatment (OR: 1.83; 95 percent confidence interval, 1.07 to 3.14; p=0.03).
JAMA Ophthalmol 2014;132:915-921.
Ying G, Kim B, Maguire M, Huang J, et al.
Following Suggested Diet Reduces Visual Impairment Risk
Australian researchers utilized a population-based cohort composed of participants from the Blue Mountains Eye Study to determine that adherence to dietary guidelines is associated with a decreased long-term risk of visual impairment in suburban Australian patients aged 65+ years.
Participants were examined at baseline, five and 10 years. The incidence of visual impairment was defined as best-corrected visual acuity <20/40 at follow-up in one or both eyes. Dietary information was obtained at baseline using a validated food frequency questionnaire. Total Diet Score was calculated based on the Australian diet quality index. TDS includes components of diet quality, poor dietary habits and energy balance. Discrete logistic regression models with time-dependent outcome variables were used to calculate hazard risk ratios and 95 percent confidence intervals associated with the incidence of visual impairment for each unit/quartile increase in TDS, adjusting for potential confounders.
Of the baseline participants in the study (n=3,654), 1,963 had up to 10 years follow-up with completed FFQs. With each unit increase in TDS, the risk of visual impairment decreased (HR 0.94; 95 percent confidence interval, 0.88 to 1.0). The risk of developing visual impairment was lower among persons in the highest compared to the lowest TDS quartile (HR 0.71; 95 percent confidence interval, 0.41 to 1.05). This association was significant among persons aged 65+ years (HR 0.63; 95 percent confidence interval 0.38 to 0.98) but not among those aged <65 years (HR 0.95; 95 percent confidence interval, 0.46 to 1.97).
Am J Ophthalmol 2014;158:302-308.
Hong T, Flood V, Rochtchina E, Mitchell P, et al.
Evaluation of MIGS with iStents And Travoprost in OAG
Researchers enrolled 39 phakic patients with open-angle glaucoma not controlled on two medications preoperatively in a prospective, open-label, non-randomized trial to evaluate the IOP-lowering effect of two trabecular microbypass stents (iStent, Glaukos Corp.) and postoperative travoprost. Patients achieved a significant and sustained reduction in IOP and medication through 18 months.
The patients had a medicated IOP between 18 mmHg and 30 mmHg, with an unmedicated baseline IOP (after washout) between 22 mmHg and 38 mmHg. Patients received two iStents through a clear corneal incision and were prescribed travoprost starting the night of postoperative day one. Complications, IOP and various safety measures were assessed at examinations through 18 months and planned for every six months after until month 60. A washout of medications was performed 13 months postop.
All patients achieved an IOP reduction of 20 percent or more from baseline to 12 months with reduction of one medication and with IOP of 18 mmHg or less. Follow-up through 18 months showed that medicated IOP decreased from 22.2 ±2 mmHg (standard deviation) on two medications preoperatively to 14 mmHg or less on one medication at the postop visits. The mean unmedicated IOP decreased from 25.3 ±1.8 mmHg preoperatively to 17.1 ±2.2 mmHg 13 months postop. No intraoperative or serious device-related adverse events occurred.
J Cataract Refract Surg 2014;
Ahmed I, Katz L, Chang D, Donnenfeld E, et al.
New Index to Monitor Central VF Progression in Glaucoma
Researchers in New York have developed and validated a new index to monitor central visual field progression that is minimally affected by the presence or removal of cataract: the central field index.
The researchers employed a retrospective cohort of glaucoma patients (176 eyes of 142 patients) with paracentral defects seen on 24-2 perimetry and followed up with at least five 10-2 visual tests to calculate an age-corrected defect depth at test points that were obtained during the 10-2 examinations. The sensitivities at these points were scored as percentages similar to the method described for the visual field index: 100-[(|total deviation|/age-corrected normal threshold)x100]. A weighting procedure was applied based on published estimates of the occipital cortical spatial magnification.
For validation, researchers performed mixed linear model testing for the association between CFI rates of change (percent per year) and known risk factors for glaucoma progression in a population with established glaucoma and at least five 10-2 VF tests. To determine whether the CFI was affected by cataract, as is known to occur with mean deviation, the researchers conducted a pilot evaluation comparing rates of CFI change in three groups: eyes with cataract; pseudophakic eyes; and eyes in which cataract surgery was performed in the middle of the series. The mean rate of CFI change of the entire sample was -1.1 percent per year (95 percent confidence interval, -1.03 to -1.16 percent per year). Elevated intraocular pressure (p<0.001) was associated significantly with faster CFI change, whereas lens status did not influence CFI rates of change (p>0.1).
De Moraes C, Furlanetto R, Ritch R, Liebmann J.
Predictors of Sustained IOP in Eyes Receiving IVI Anti-VEGF
New York researchers asked 530 retina specialists, spanning both private and academic practice, about their current anti-VEGF protocols, including anti-VEGF drug of choice, needle gauge, injection volume, injection technique and self-reported prevalence of sustained intraocular pressure elevation. Based on survey data, it appears that serial anti-VEGF injections using higher injection volumes with a rapid injection technique may potentially lead to sustained IOP elevation.
Two hundred ninety-two specialists (55 percent) reported believing that intravitreal anti-VEGF therapy may cause sustained IOP elevation. Of these responses, the most common reported prevalence was 1 to 2 percent (48 percent), followed by 3 to 5 percent (34 percent). There was no relationship between frequency of sustained IOP elevation and anti-VEGF drug of choice. Physicians who injected more than 0.05 cc in less than one second were 5.56 times more likely to observe a high frequency of sustained IOP elevation (p=0.006; 95 percent confidence interval, 1.64 to 18.89). The underlying mechanism for this complication may be injury to the trabecular meshwork resulting from rapid elevation in IOP.
AM J Ophthalmol 2014;158:319-327.
Yannuzzi N, Patel S, Bhavsar K, Sugiguchi F, Freund K.