Smoking has a number of negative effects on the body, and a recent study indicates that it may contribute to worse visual outcomes as well. A research team investigated the effect of smoking status on the one-year visual outcomes in eyes treated with anti-VEGFs for nAMD. 

Their retrospective, observational analysis included 987 treatment-naïve eyes of 837 patients with nAMD. Smoking status was documented at baseline; anti-VEGF therapy took place over a period of 11 years, from January 2006 to December 2016.

The researchers reported a significant difference in mean improvement in visual acuity at 12 months between nonsmokers, ex-smokers and current smokers (7.7 vs. 6.1 vs. 3.5 letters; p=0.046). The median number of anti-VEGF injections over the 12 months was not significantly different by smoking status, and the researchers noted that current smokers were on average 6.2 years younger than nonsmokers when starting treatment.

Additionally, the analysis of smoking effects on nAMD treatment outcomes revealed significant differences between smoking groups for baseline VA and baseline choroidal neovascular membrane size. Current smokers have an up to sevenfold greater risk of developing nAMD than nonsmokers, and despite being younger, the researchers noted that these patients tended to have more aggressive disease with worse baseline VA and larger CNVM. Nonsmokers also had more than twice the gain in VA after a year.

The researchers concluded that patients who continued to smoke while undergoing anti-VEGF therapy for nAMD experienced inferior 12-month and 24-month visual outcomes. The mechanism of association between current smoking and poorer visual outcomes with anti-VEGFs is unclear, but the authors suspect a genetic component may influence nAMD treatment outcomes. 

Retina 2020;40:1696-1703. 
Vittorio AF, Nguyen V, Barthelmes D, et al.

Quantifying IOP Reduction after Cataract Surgery
A retrospective study conducted by researchers in Portugal and the United Kingdom sought to define the extent of intraocular pressure reduction caused by uncomplicated cataract surgery in individuals with glaucoma vs. those with healthy eyes, to guide physicians hoping to use cataract surgery as an intervention for glaucoma. (The authors note a lack of data in the literature covering this topic in eyes with intraocular pressure measurements below 30 mmHg and open angles.) They hoped to contribute to the eventual creation of a formula that would allow physicians to predict intraocular pressure reduction using basic demographic and clinical measures.

Data from surgeries performed at eight sites in the United Kingdom between January 2006 and May 2015, involving 22,831 eyes—20,580 healthy eyes and 2,251 eyes with glaucoma—were analyzed. Eyes with intraoperative complications, extreme axial lengths, baseline IOP below 6 mmHg or above 20 mmHg, or other pathologies (with the exception of amblyopia), or that were undergoing multiple procedures, were excluded. (The authors note that information regarding glaucoma subtypes, topical medication use and previous glaucoma surgery was not available.)

In healthy eyes the mean IOP reduction was 1.4 ±3.74 mmHg; in glaucomatous eyes the mean reduction was 1.03 ±5.02 mmHg. Analysis using multiple linear regression found that factors associated with amount of IOP reduction included preoperative IOP, preoperative corrected visual acuity, age, axial length and a diagnosis of glaucoma. The authors conclude that in glaucomatous eyes not differentiated by degree of angle closure or other contributory factors, phacoemulsification alone produces only a modest reduction in IOP—an amount that may not be clinically meaningful.

J Glaucoma 2020;29:8:689-93
Leal I, Chu CJ, Yang YY, et al.

Follow-up in Proliferative Diabetic Retinopathy Care
An unprecedented study of interrupted treatment of proliferative diabetic retinopathy has found that 61 percent of patients with shared risk factors, such as not speaking English as a primary language and being 56 years old or older, were lost to follow-up treatment for more than six months at least once. Previous studies found this level of non-compliance in only 28.8 percent and 25.4 percent of patients.

The findings resulted from a retrospective cohort chart review of 418 adult patients with PDR who had been treated with intravitreal anti-VEGF injections and/or panretinal photocoagulation between January 1, 2014, and June 1, 2018, at the Boston University School of Medicine. Only 5 to 10 percent of patients have been lost to follow-up in clinical trials, the study noted.

A multivariate analysis identified the following risk factors for the studied patients: Non-English as the primary language (odds ratio [OR], 1.83; p=0.006); age 56 to 65 years old (OR, 1.86; p=0.014); age older than 65 years compared to age 55 years or younger (OR, 1.94; p=0.027); living 20 miles or less from the institution (OR, 2.68; p=0.009); having more than five comorbidities (OR, 2.38; p=0.034); seeing 20 or more distinct departments (OR, 4.66; p=0.007); missing more than 10 percent of non-eye-care appointments (OR, 1.61; p=0.038) and receiving only panretinal photocoagulation compared to only anti-VEGF therapy (OR, 1.93; p=0.031).

The study authors say that, to date, this is the most comprehensive study examining risk factors for LTFU (lost to follow-up) in patients being treated for proliferative diabetic retinopathy. They note that many of the variables assessed in this study have not been examined in this context previously. Besides primary language, some of these variables included history of mental illness and substance abuse, homelessness and food insecurity, insurance type, and history of noncompliance and missed appointments in other settings. Additionally, the study reported a disparity between the use of anti-VEGF therapy and panretinal photocoagulation. When comparing anti-VEGF agents to PRP, landmark studies have established ranibizumab monotherapy and aflibercept to be non-inferior and superior, respectively, the researchers observed. However, this study shows that these findings often don’t match findings in the clinical environment.

Identifying patients at high risk for being lost to follow-up may help in choosing treatment modality and appropriate patient counseling, the study concluded.

Am J Ophthalmol 2020;216:18-27.
Green M, Tien T, Ness S.  

Microvascular Impairments in Non-DR Diabetic Patients
Researchers used optical coherence tomography angiography to evaluate microvascular impairments in the eyes of diabetic patients with no diabetic retinopathy, as part of a systematic review and meta-analysis.

They searched PubMed and Embase databases to identify studies using optical coherence tomography angiography to compare microvascular changes between diabetic eyes without clinical retinopathy and healthy controls. They extracted and analyzed data of interest using Review Manager V.5.3 and Stata V.14.0. They used weighted mean differences and their 95% confidence intervals to assess the strength of the association.

Forty-four cross-sectional studies involving 2,221 diabetic and 1,838 healthy eyes were included. 

Here are some of the study’s findings: 

• OCTA imaging revealed that, when compared to the healthy control group, the no-diabetic-retinopathy group manifested enlarged areas and increased perimeters of the foveal avascular zone, with decreased perfusion density in the superficial and deep capillary plexus of the macula (except parafoveal perfusion density of the inner retina and foveal perfusion density) and reduced radial peripapillary capillary perfusion density values. 

• In addition, subgroup analyses according to the type of diabetes mellitus indicated that most of those differences became nonsignificant (except parafoveal PD in the deep capillary plexus) in type 1 diabetes mellitus, while in type 2 diabetes mellitus, they remained statistically significant.

The researchers wrote that their findings suggested that retinal microvascular impairments might have occurred prior to clinically visible diabetic retinopathy and could be detected early by optical coherence tomography angiography. However, they added, those manifestations could be inconsistent depending on the type of diabetes mellitus.  REVIEW

Am J Ophthalmol 2020; Sept 31. [Epub ahead of print].
Zhang B, Chou Y, Zhao X, et al.