Research Digest

Pseudodrusen and dry AMD.

Retinal physicians in New York have found that pseudodrusen are a predictor of late-stage dry AMD and that they affect visual function.

In a prospective, cross-sectional study, the authors subjected 51 dry AMD-affected eyes belonging to 39 patients to multiple imaging modalities, including spectral-domain OCT, fundus photography and fundus autofluorescence. The images were subsequently graded by readers blinded to the diagnoses. The eyes were also measured for visual acuity, contrast sensitivity and microperimetry.

As noted, pseudodrusen was a statistically significant predictor of contrast sensitivity and of parafoveal and macular microperimetry scores. In addition, refractive error was a predictor of contrast sensitivity, and confluent hypoautofluorescence was a predictor of parafoveal microperimetry score.

While acknowledging that little is known about pseudodrusen, the authors emphasize the importance of the relationships found in their study, particularly with regard to the planning of low-vision accommodation.

AMD rates in Ireland.

Using data from the Irish Longitudinal Study on Ageing (TILDA), ophthalmologists sought to determine the prevalence of AMD in Ireland. In this country, AMD is thought to be the cause of 25% of all blind registration.

From the initial cohort of 8,175 subjects, the authors identified 4,751 people who had retinal photographs in their charts considered suitable for grading. Researchers blinded to diagnoses subsequently graded the images.

The authors found a 7.2% rate of AMD in the cohort, consisting of 6.6% with early AMD and 0.6% with late AMD. Geographic atrophy and wet AMD were each present in 0.3% of the cohort. Among other findings, the risk factors identified for the disease included increasing age and a family history.

The rates found in the study were less than those found in the Reykjavik (Iceland) Eye Study but comparable to those in Caucasian patients in the MESA study conducted in the United States, perhaps because of the high rate of Irish ancestry among Americans.

QoL in mild glaucoma.

Doctors in China collaborating with an epidemiologist from the University of Michigan found that ophthalmologists tend to underestimate mild glaucoma’s impact on their patients’ quality of life (QoL).

The study authors enrolled 87 patients with primary or secondary open-angle glaucoma or with chronic angle-closure glaucoma, all of whom had reliable Humphrey field test results. QoL questionnaires were then administered to the patients, as well as to the ophthalmologists on the faculty of the hospital from which the patients were recruited.

Using utility analysis to determine QoL (numbers closer to one indicating better quality of life), the authors found that while the patients with mild glaucoma reported utility values between 0.70 and 0.77, the ophthalmologists estimated that the utility values in mild glaucoma would range from 0.81 to 0.95; this difference was statistically significant. The ophthalmologists also underrated the lowest utility value for moderate to severe glaucoma (0.35 vs. 0.56 according to patients).

The authors suggest that the disparity in the findings is related to the tendency of ophthalmologists to attach greater importance to the most observable aspects of QoL, such as visual function. Patients attach greater importance than ophthalmologists to emotional and social factors of QoL. Better patient-doctor communication is therefore warranted.

OCTA study in diabetic patients.

Using the new imaging modality of OCT angiography (OCTA), doctors in Beijing investigated the area and radius of the foveal avascular zone (FAZ) in patients with diabetes, reporting larger FAZs in these patients.

In a comparative, cross-sectional study, 113 eyes of 65 patients with diabetes and 85 eyes of 62 normal controls were submitted to OCTA for measurement of the area FAZ, as well as of its vertical and horizontal radii.

They found that all three dimensions of the FAZ were larger in diabetic patients. In addition, after dividing the diabetic patients into groups without diabetic retinopathy, with DR and with clinically significant macular edema (CSME), they found differences in area when comparing the controls with the patients without DR and with those with CSME.

The authors conclude that a larger FAZ is a baseline difference in the presence of diabetes, regardless of whether DR or CSME is present. Nevertheless, they acknowledge the limitations of the study, including the newness of OCTA, and recommend further research.OM