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AMD in a Multi-Ethnic U.S. Population
June 2016
Fisher et al. described the incidence of age-related macular degeneration (AMD) and the effect of risk factors among 4 racial/ethnic groups residing in the United States—white, black, Hispanic, and Chinese. They found substantial variation of AMD incidence among these groups, with whites having the highest rate and blacks having the lowest.
In this prospective cohort study, the researchers examined 3,811 participants from the Multi-Ethnic Study of Atherosclerosis who ranged in age from 46 to 86. Fundus photography was performed on each participant twice, on average, at an interval of 8 years. The photos were graded at a central reading facility according to the Wisconsin Age-Related Maculopathy Grading System. The images were assessed for early and late AMD based on drusen size, type, and area; increased retinal pigment; retinal pigment epithelial depigmentation; neovascular lesions; and geographic atrophy. Demographic, clinical, and laboratory measures were included in multivariable regression models to determine their impact on the variation in AMD incidence among racial and ethnic groups.
The overall 8-year age- and sex-standardized incidence of early and late AMD was 4.1% and 2.3%, respectively. The incidence of early and late AMD, respectively, was highest in whites (5.3% and 4.1%); intermediate in Chinese individuals (4.5% and 2.2%) and Hispanics (3.3% and 0.8%); and lowest in blacks (1.6% and 0.4%). After adjustment for age and gender, black individuals had a 70% lower risk of developing early AMD than did whites; after multivariable adjustment, this finding decreased only slightly to 67%.
When adjustments were made for age, gender, and race/ethnicity, hyperopia and astigmatism were associated with early AMD; myopia was not. Age, race/ethnicity, current smoking, hyperopia, and AMD candidate gene variants CFH RS1061170 and ARMS2 RS3793917 were independently associated with incident early AMD in multivariable models for the combined sample. However, increasing age was the only statistically significant factor consistently associated with incident early AMD across the 4 racial/ethnic groups.
Although earlier reports have hypothesized that the presence or absence of certain gene alleles may be responsible for the differences, in this study, the genetic, clinical, and environmental factors assessed did not account for racial/ethnic differences seen in AMD incidence.
Latanoprostene Bunod Versus Timolol Maleate in Open-Angle Glaucoma
May 2016
Latanoprostene bunod (LBN) is a novel monotherapy with the pharmacologic activity of both a prostaglandin F2α analogue and the physiologic signaling mediator nitric oxide. Weinreb et al. compared the diurnal intraocular pressure (IOP)-lowering effect of LBN ophthalmic solution 0.024% once every evening (qPM) with timolol maleate 0.5% twice daily (BID) among patients with open-angle glaucoma (OAG) or ocular hypertension (OHT).
The study was a multicenter phase 3 randomized controlled double-masked parallel-group trial. Of the 420 randomized subjects, 387 completed the study: 264 who took LBN 0.024% and 123 who took timolol 0.5%. All participants were aged 18 or older and had been diagnosed with OAG or OHT in 1 or both eyes. The 3-month regimen included LBN qPM (plus a placebo drop in the morning to maintain masking) or 1 timolol drop BID. IOP was measured at 8 a.m., 12 p.m., and 4 p.m. at each postrandomization visit (week 2, week 6, and month 3).
The primary efficacy end point was IOP at each of the 9 assessment time points. Secondary end points were the proportion of patients with an IOP of ≤18 mm Hg consistently at all 9 time points and the proportion of patients with an IOP reduction ≥25% consistently at all 9 time points.
The researchers reported that at all 9 time points, the mean IOP in the study eye was significantly lower in the LBN group (range, 17.8-18.7 mm Hg) than in the timolol group (range, 19.1-19.8 mm Hg). In addition, the percentage of subjects with mean IOP ≤18 mm Hg was significantly higher in the LBN group compared with the timolol group (22.9% vs. 11.3%), as was the percentage of subjects with IOP reduction ≥25% (34.9% vs. 19.5%). The incidence of treatment-related adverse events—chiefly ocular irritation and conjunctival hyperemia—was low and occurred at similar rates between the 2 groups.
Topical Corticosteroids in Conjunction With Antiamoebic Therapy
May 2016
Many cornea specialists are uncertain about the risk-benefit balance of topical steroid use in the treatment of Acanthamoeba keratitis (AK). Carnt et al. performed a cohort study on the effect of topical corticosteroids administered after initiation of antiamoebic therapy (AAT). They found that use of steroids in this setting was not associated with worse outcomes and may provide benefits.
The study included 196 patients (1 eye each) diagnosed with AK at Moorfields Eye Hospital in London between January 1991 and April 2012. After exclusion of patients who had coexisting scleritis or hypopyon, outcomes for 129 patients were analyzed: 74 who received topical steroids after the start of AAT and 55 who received AAT but no steroids. (However, some patients in both groups had received steroids before diagnosis of AK.) The main outcome measure was a suboptimal outcome, which was defined as a final visual acuity of ≤20/80, corneal perforation, or the need for keratoplasty.
After multivariable analysis, the researchers found that topical corticosteroids started after initiation of AAT were not associated with a worse outcome (odds ratio [OR], 1.08); however, topical corticosteroid use before the start of AAT was a significant risk factor (OR, 3.85) for worse outcome, as were the presence a corneal ring infiltrate (OR, 5.89) and age 33 years or older at the start of ATT (OR, 4.02).
The authors concluded that clinicians and patients can be reassured that steroid use initiated after AAT is not associated with a worse outcome and, further, that it has several potential benefits, including reducing pain, corneal vascularization, and severe corneal stromal inflammation.
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Ophthalmology summaries are written by Marianne Doran and edited by Susan M. MacDonald, MD.
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