Refractive Error, Glaucoma, and Ethnicity
What is the association between refractive error and glaucoma when race and ethnicity are factored in? Shen et al. explored this question and found that myopia and hyperopia are associated with particular forms of glaucoma. The investigators looked at primary angle-closure glaucoma (PACG) and 3 types of open-angle glaucoma: primary open-angle glaucoma (POAG), normal-tension glaucoma (NTG), and pseudoexfoliation glaucoma.
For this cross-sectional study, the researchers gathered data (2008-2014) from the electronic health records of members of a Northern California health plan who were aged 35 or older with a documented refractive error. Within this group, 34,040 members had a diagnosis of glaucoma or ocular hypertension (OHTN) and 403,398 had neither. The latter served as controls.
Hyperopia was associated with PACG, while myopia was associated with an increased prevalence of all forms of open-angle glaucoma and OHTN, the researchers found. The magnitudes of the associations were strongest for those with the greatest refractive error.
In terms of ethnicity, a stronger association was seen between myopia and POAG among non-Hispanic whites, and between myopia and NTG among Asians and non-Hispanic whites. The association between hyperopia and PACG extended across all racial and ethnic groups.
Steroid Injections Raise Risk of Endophthalmitis
VanderBeek et al. set out to determine whether the rates of postinjection endophthalmitis differ between injection of intravitreal steroid and anti-VEGF drugs. They found that the risk of endophthalmitis is higher with steroid injections.
For this retrospective cohort study, the researchers evaluated 406,380 intravitreal injections (75,249 patients) administered between 2003 and 2012. Of these, 387,714 were anti-VEGF injections (bevacizumab, ranibizumab, aflibercept, or pegaptanib), and 18,666 were steroid injections (triamcinolone or dexamethasone).
A total of 73 cases of endophthalmitis occurred in the anti-VEGF group, for a rate of 1 per 5,283 injections (0.019%). In contrast, 24 cases occurred in those who received steroid injections, for a rate of 1 per 778 injections (0.13%).
The authors hypothesized that the larger-gauge needle used for steroid injections may play a role by creating a bigger needle track for easier bacterial penetration into the vitreous. The immunosuppressive nature of the steroids may be an additional risk factor.
This study is the largest collection of data on intravitreal steroid injections and endophthalmitis cases to date. The most significant limitation of this study was lack of access to laboratory culture results, the authors noted, which prevented confirmation of type of endophthalmitis from the charts.
CRAO and Risk of Stroke and Myocardial Infarction
Park et al. investigated the risk and timing of stroke and acute myocardial infarction (AMI) in patients with central retinal artery occlusion (CRAO). They found an increased risk of ischemic stroke just after CRAO occurs, particularly in the first week.
For this case series, the researchers used the Korean national claims database of 48 million individuals. They identified 1,655 patients who had CRAO in the time period 2009-2010. Of these, 139 had an ischemic stroke, 13 had a hemorrhagic stroke, and 15 had an AMI during the year immediately preceding or following the CRAO. After statistical analyses were performed, the study did not find significant associations with hemorrhagic stroke or AMI. The researchers cautioned, however, that this lack of significance could be due in part to the small number of such occurrences during the study period, and they did not discount the possibility of a longer-term risk.
Further analysis showed that the risk of ischemic stroke was particularly high in the first week after CRAO and continued to be elevated throughout the first 30 days. Given these findings, the authors suggest that patients with incident CRAO should receive immediate neurologic evaluation and preventive treatment to reduce morbidity and mortality from stroke.
Anti-VEGF Injections and Cataract Surgery Outcomes
Hahn et al. investigated the effect of prior intravitreal anti-VEGF injections on cataract surgery outcomes and complication rates. They found that patients with a history of intravitreal injections may be at greater risk for intraoperative complications and postoperative endophthalmitis.
For this retrospective cohort analysis, the researchers evaluated 203,643 Medicare beneficiaries who underwent cataract surgery from 2009 to 2013, using a 5% sample of claims data. The primary outcome was the risk of subsequent removal of retained lens fragments within 28 days; secondary outcomes included endophthalmitis (both acute and delayed-onset) and a new diagnosis of primary open-angle glaucoma (POAG).
Prior intravitreal anti-VEGF injections were associated with a significantly increased risk of retained lens fragments (hazard ratio [HR], 2.26), acute endophthalmitis (HR, 2.29), and delayed-onset endophthalmitis (HR, 3.65). However, they were not associated with greater risk of a new POAG diagnosis.
The researchers recommended that cataract surgeons should employ increased preoperative assessment, additional intraoperative caution, and postoperative vigilance in patients who have received anti-VEGF treatment.
Ophthalmology summaries are written by Jean Shaw and edited by Susan M. MacDonald, MD.
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