Andrew M. Hendrick

Comparison Among Methods of Retinopathy Assessment (CAMRA) Study: Smartphone, Nonmydriatic, and Mydriatic Photography

PURPOSE We compared smartphone fundus photography, nonmydriatic fundus photography, and 7-field mydriatic fundus photography for their abilities to detect and grade diabetic retinopathy (DR). DESIGN This was a prospective, comparative study of 3 photography modalities. PARTICIPANTS Diabetic patients (n = 300) were recruited at the ophthalmology clinic of a tertiary diabetes care center in Chennai, India. METHODS Patients underwent photography by all 3 modalities, and photographs were evaluated by 2 retina specialists. MAIN OUTCOME MEASURES The sensitivity and specificity in the detection of DR for both smartphone and nonmydriatic photography were determined by comparison with the standard method, 7-field mydriatic fundus photography. RESULTS The sensitivity and specificity of smartphone fundus photography, compared with 7-field mydriatic fundus photography, for the detection of any DR were 50% (95% confidence interval [CI], 43-56) and 94% (95% CI, 92-97), respectively, and of nonmydriatic fundus photography were 81% (95% CI, 75-86) and 94% (95% CI, 92-96%), respectively. The sensitivity and specificity of smartphone fundus photography for the detection of vision-threatening DR were 59% (95% CI, 46-72) and 100% (95% CI, 99-100), respectively, and of nonmydriatic fundus photography were 54% (95% CI, 40-67) and 99% (95% CI, 98-100), respectively. CONCLUSIONS Smartphone and nonmydriatic fundus photography are each able to detect DR and sight-threatening disease. However, the nonmydriatic camera is more sensitive at detecting DR than the smartphone. At this time, the benefits of the smartphone (connectivity, portability, and reduced cost) are not offset by the lack of sufficient sensitivity for detection of DR in most clinical circumstances.

Cost-effectiveness of Different Diabetic Retinopathy Screening Modalities

Current screening strategies aimed at detection of diabetic retinopathy (DR) historically have poor compliance, but advancements in technology can enable improved access to care. Nearly 80% of all persons with diabetes live in low- and middle-income countries (LMICs), highlighting the importance of a cost effective screening program. Establishing mechanisms to reach populations with geographic and financial barriers to access is essential to prevent visual disability. Teleretinal programs leverage technology to improve access and reduce cost. The quality of currently employed screening modalities depends on many variables including the instrument used, use of pupillary mydriasis, number of photographic fields, and the qualifications of the photographer and image interpreter. Recent telemedicine and newer technological approaches have been introduced, but data for these technologies is yet limited. We present results of a systematic review of studies evaluating cost-effectiveness of DR screening, and discuss potential relevance for LMICs.

Current and Next Generation Portable Screening Devices for Diabetic Retinopathy

Diabetic retinopathy (DR) is the leading cause of legal blindness in the United States, and with the growing epidemic of diabetes, a global increase in the incidence of DR is inevitable, so it is of utmost importance to identify the most cost-effective tools for DR screening. Emerging technology may provide advancements to offset the burden of care, simplify the process, and provide financially responsible methods to safely and effectively optimize care for patients with diabetes mellitus (DM). We review here currently available technology, both in production and under development, for DR screening. Preliminary results of smartphone-based devices, “all-in-one” devices, and alternative technologies are encouraging, but are largely pending verification of utility when used by nonophthalmic personnel. Further research comparing these devices to current nonportable telemedicine strategies and clinical fundus examination is necessary to validate these techniques and to potentially overcome the poor compliance around the globe of current strategies for DR screening.

Toxoplasma chorioretinitis diagnosed by histopathology in a patient with AIDS.

PURPOSE To demonstrate the diagnostic difficulties in cases of retinal necrosis in immunocompromised patients including the potential for false-negative anterior segment sampling and also to emphasize the utility of diagnostic vitrectomy with histopathologic examination. METHODS This patients chart was thoroughly reviewed to present salient features that are relevant to any ophthalmologist attempting to diagnose and treat chorioretinitis. A 38-year-old man with HIV/AIDS who presented with bilateral retinal necrosis. Thorough workup, including multiple samples of anterior chamber fluid for polymerase chain reaction, was negative. RESULTS Diagnostic vitrectomy revealed a toxoplasma cyst. Triple therapy stabilized retinitis, although vision did not improve. CONCLUSION This case reminds the clinician to consider a broad differential diagnosis for retinal necrosis in immunocompromised hosts and, when serologic and anterior chamber samples are negative, to consider diagnostic vitrectomy for polymerase chain reaction and histopathologic examination.

Association of serum vitamin D levels and diabetic retinopathy in Asian Indians with type 2 diabetes

BACKGROUND Vitamin D deficiency (VDD) is a condition that has been associated with diabetic retinopathy (DR) in various populations, but has not been studied in Asian Indians. AIMS To evaluate the association of serum 25-hydroxyvitamin D (25(OH)D) levels with presence and severity of DR among Asian Indians with type 2 diabetes. METHODS We collected information on individuals with type 2 diabetes that received care at a tertiary diabetes centre in India, between 2012 and 2015. Patients were 18 years of age or older, underwent retinal examinations with DR severity grading and had serum 25(OH)D measurements. RESULTS Serum 25(OH)D levels were lower in patients with retinopathy compared to those without (11.9 ± 2.2 ng/ml vs. 13.7 ± 2.1 ng/ml, p < 0.001). Stratifying patients by DR grade, reduced geometric means of 25(OH)D levels were associated with increased retinopathy severity. After adjusting for six key covariates, VDD was associated with increased rates of proliferative DR (OR 2.05; 95% CI 1.35-3.11; p = 0.001). CONCLUSIONS In Asian Indians with type 2 diabetes, lower serum 25(OH)D was associated with increased severity of DR and the presence of VDD was associated with a two-fold increased risk for proliferative DR.

Management of proliferative diabetic retinopathy

Advancement from nonproliferative diabetic retinopathy (NPDR) into the proliferative stage is defined by the presence of neovascularization, or new blood vessel growth. Although neovascularization would seemingly be a helpful adaptation, ocular neovascularization is uniformly destructive and associated with a poor visual prognosis when unchecked.