Using the Clinformatic DataMart database, researchers sought to understand the risk factors for nonarteritic anterior ischemic optic neuropathy, a devastating ocular disease that causes permanent vision loss. In order to isolate and explore NAION’s risk factors, researchers specifically looked at associated demographic, systemic and ocular factors.

This retrospective, longitudinal cohort study included patients between 40 and 75 years old without NAION at baseline who were enrolled in a large U.S. managed-care network. These enrollees were monitored for at least two years between 2001 and 2014 to identify those newly diagnosed with NAION. All persons were under ophthalmic surveillance, and all cases had ≥1 confirmatory ICD-9-CM code for NAION during follow-up.

Of the 1,381,477 eligible enrollees, 977 (0.1 percent) developed NAION during a mean ±standard deviation follow-up of 7.8 ±3.1 years. The ±D mean age for NAION cases at the index date was 64.0 ±9.2 years vs. 58.4 ±9.4 years for the remainder of the beneficiaries. Female subjects had a 36-percent decreased risk of developing NAION compared with male subjects. Compared with whites, Latinos had a 46-percent decreased risk of developing NAION, whereas African ancestry was not significantly associated with NAION. Systemic diseases associated with NAION included hypertension and hypercoagulable states. Although diabetes mellitus was not significantly associated with NAION when compared with those without DM (p=0.45), patients with end-organ involvement from DM had a 27-percent increased risk of NAION relative to those with uncomplicated DM. Ocular diseases associated with NAION were age-related macular degeneration and retinal vein occlusion.

The study identified several modifiable risk factors that may be associated with NAION. Should future studies confirm these findings, they may offer opportunities to prevent or treat this debilitating condition, the researchers say.

Ophthalmology 2016;123:2446-2455
Cestari D, Gaier E, Bouzika P, Blachley T

Air Pollution and Central Retinal Artery Occlusion
Researchers investigated whether daily changes in ambient air pollution were associated with an increased risk of central retinal artery occlusion, using the Taiwan National Health Insurance Research Database.

This retrospective, population-based, cohort study identified patients newly diagnosed with CRAO between 2001 and 2013 in a database of 1,000,000 patients that were randomly selected from all registered beneficiaries of the National Health Insurance program in Taiwan. The researchers referenced air pollutant monitoring stations located near these patients’ residences throughout Taiwan to determine the recorded concentrations of pollutants. Patients without corresponding monitoring stations were excluded.

Using a time-stratified, case-crossover study design and conditional logistic regression analysis, researchers assessed associations between the risk of CRAO and the air pollutant levels in the days preceding each increase in those levels. Ninety-six patients with CRAO were enrolled in this study. The mean age was 65.6 years, and 67.7 percent of the patients were male.

The risk of CRAO onset was significantly increased during a five-day period following a one-part-per-billion increase in pollutant levels. After multi-pollutant adjustment, the increase in risk was most prominent after four to five days in diabetic patients. The risk of CRAO onset also significantly increased in patients with hypertension and in patients ≥65 years old after just one day of elevated pollutant levels. The results demonstrated a positive association between air pollution and CRAO onset, particularly in patients with diabetes or hypertension and those older than 65 years.

Ophthalmology 2016;123:2603-2609
Cheng HC, Pan RH, Yeh HJ, Lai KR, Yen MY

Intravitreal Bevacizumab for DME
Researchers from the U.K. wrote that since outcomes of intravitreal anti-vascular endothelial growth factor injections are variable among individuals with diabetic macular edema, they set out to determine the ocular and systemic predictors of DME response to intravitreal bevacizumab. The study was a retrospective review over two years. They defined an anatomical response to IVB as a 20-percent reduction in central macula thickness after the first course (three injections) of IVB.

In 78 eyes of 54 individuals, 28 percent of cases had an anatomical response after the first course of IVB. Systemic hypertension (odds ratio: 12.1; 95 percent-CI: 0.7 to 21) was a statistically significant predictor (p=0.025) of a good response to IVB, while previous macular laser was a statistically significant (p=0.0005) predictor of a poor response (odds ratio: 0.07; 95-percent CI: 0.01 to 0.32). Sixty-eight percent of eyes underwent subsequent treatment for DME after the first course of IVB. The visual acuity gain at 24 months in hypertensive individuals (0.7 ±3.6 letters) and nonhypertensive individuals (5.2 ±3.7 letters) was not statistically significantly different (p=0.41).

Researchers concluded that hypertension was a positive predictor, and previous macular laser was a negative predictor of response to IVB. However, they found that long-term visual acuity changes weren’t significantly different between eyes with or without systemic hypertension.

Clin Ophthalmol 2016;10:2093-8
Joshi L, Bar A, Tomkins-Netzer O, et al.