No abstract

The prevalence of diabetes has been accelerating at an alarming rate in the last decade; some describe it as an epidemic. Diabetic eye complications are the leading cause of blindness in adults aged 25-74 in the United States. Early diagnosis and development of effective preventatives and treatments of diabetic retinopathy are essential to save sight. We describe efforts to establish functional indicators of retinal health and predictors of diabetic retinopathy. These indicators and predictors will be needed as markers of the efficacy of new therapies. Clinical trials aimed at either prevention or early treatments will rely heavily on the discovery of sensitive methods to identify patients and retinal locations at risk, as well as to evaluate treatment effects.We report on recent success in revealing local functional changes of the retina with the multifocal electroretinogram (mfERG). This objective measure allows the simultaneous recording of responses from over 100 small retinal patches across the central 45 degree field. We describe the sensitivity of mfERG implicit time measurement for revealing functional alterations of the retina in diabetes, the local correspondence between functional (mfERG) and structural (vascular) abnormalities in eyes with early nonproliferative retinopathy, and longitudinal studies to formulate models to predict the retinal sites of future retinopathic signs. A multivariate model including mfERG implicit time delays and 'person' risk factors achieved 86% sensitivity and 84% specificity for prediction of new retinopathy development over one year at specific locations in eyes with some retinopathy at baseline. A preliminary test of the model yielded very positive results. This model appears to be the first to predict, quantitatively, the retinal locations of new nonproliferative diabetic retinopathy development over a one-year period. In a separate study, the predictive power of a model was assessed over oneand two-year follow-ups. This permitted successful prediction of new retinopathy development in eyes with and without retinopathy at baseline. Finally, we briefly describe our current research efforts to (a) locally predict future sight-threatening diabetic macular edema, (b) investigate local retinal function change in adolescent patients with diabetes, and (c) better understand the physiological bases of the mfERG delays.The ability to predict the retinal locations of future retinopathy based on mfERG implicit time provides clinicians a powerful tool to screen, follow up, and even consider early prophylactic treatment of the retinal tissue in diabetic patients. It also aids identification of 'at risk' populations for clinical trials of candidate therapies, which may greatly reduce their cost by decreasing the size of the needed sample and the duration of the trial.

No abstract

Localized functional abnormalities of the retina reflected by mfERG delays often precede the onset of new structural signs of diabetic retinopathy. Those functional abnormalities predict the local sites of new retinopathy observed 1 year later.

mfERG IT is a good predictor of DR onset, 1 year later, in patients with diabetes without DR. It can be used to assess the risk for DR development in these patients and may be a valuable outcome measure in evaluation of novel prophylactic therapeutics directed at impeding DR.

The development of recurring retinopathy over a 3-year period can be well predicted by using a multivariate model based on mfERG implicit time. Multifocal ERG delays are promising candidate measures for trials of novel therapeutics directed at preventing or slowing the progression of NPDR.

Vision functions other than standard visual acuity may affect day-to-day functioning of older adults. Additional studies of these other aspects of vision and how they can be treated or rehabilitated are needed to determine whether these aspects play a role in strategies for reducing disability in older adults.

We present an overview of a multifaceted longitudinal study of vision function and its interaction with daily activities, health, and well-being among 900 persons aged 58 to 102 years at the first visit. Standard vision measures as well as nonconventional tests designed to assess visual performance under the nonideal conditions encountered in everyday life were used. Here we summarize a few of the findings to date, with an emphasis on a direct comparison of declines in different aspects of vision function with age. The rates of declines with advancing age vary widely for the different vision functions. Also described is the reading performance of the sample and its association with some of the vision measures. Furthermore, we describe some of the associations between vision test scores and extensive longitudinal health and functioning data collected by the Buck Center for Research in Aging. Findings show that many older people with good acuity are effectively visually impaired in performing everyday tasks involving low and changing light levels, stereopsis, glare, and low contrast. We also found that vision under nonideal conditions cannot be predicted from standard acuity on an individual basis.