Anthony J. Adams

Professor of Vision Science and Optometry

Vision in diabetes; Color vision; Assessment of retinal function

Diabetes is the leading cause of severe vision loss in the working age population (20-74 yrs). Diabetic retinopathy is responsible for the vast majority of this loss. Yet treatments of retinopathy by laser surgery, though dramatic, do not prevent, reverse or eliminate the retinopathy and are accompanied by significant vision side effects; laser treatments slow the progression of retinopathy and vision loss. Recent research efforts have been directed at direct pharmaceutical interventions to treat retinopathy.

Research Goals

New pharmacological candidates for treatment and prevention of diabetic retinopathy can only be evaluated if there are identifiable vision and functional risk factors identified PRIOR to the development of irreversible damage to the retina (retinopathy). Our research is directed toward identifying those vision and functional retinal markers.

We apply both human psychophysical (S-cone sensitivity) and electrophysiological (ERG and EOG) methods in our study of diabetics and non diabetic controls.

Psychophysics: Earlier we demonstrated that S-cone ("blue cone") pathway sensitivity losses at the fovea precede diabetic retinopathy and that this sensitivity fluctuates with diabetic blood glucose levels- even during the day. Now the application of S-cone sensitivity measures to visual field testing is commercially available and in clinical use. In our research we study diabetic subjects with and without retinopathy to predict areas of future irreversible retinopathic damage.

Electrophysiology - ERG: We have also recently shown that local electroretinograms (mfERGs) reveal functional loss in patches of retina not only associated with patches of retinopathy but also in areas apparently free of retinal damage. Our research involves the testing of the hypothesis that these patches of functional loss correspond to the patches of retina at highest risk for subsequent retinopathic damage.

Electrophysiology - EOG: We recently showed direct effects of acute glycemic levels on human vision function measured by electrophysiological methods. We have shown that he FEOG is very sensitive to blood glucose fluctuations in both non-diabetics and diabetics. And, the diabetic FEOG (fast EOG) appears to differ from that of the non-diabetic. The FEOG, a non-invasive objective measure of the eye's electrical response to light at the RPE/photoreceptor interface, reflects chloride transport at the basal membrane of the retinal pigment epithelium.

The research has promise for guiding future studies of local site specific preventative treatments.

Selected Publications

Schneck ME, Fortune B, Switkes E, Crognale M, Adams AJ. Acute effects of blood glucose on chromatic VEP's in diabetic and normal individuals. Investigative Ophthalmology & Visual Science, 38, 800-810, 1997.

Fortune B, Schneck ME, Adams AJ. Multifocal electroretinogram delays reveal local retinal dysfunction in early diabetic retinopathy. Investigative Ophthalmology & Visual Science, 1999, 40/11, 2638-2651.

Schneck ME, Fortune B, and Adams AJ. The fast oscillation of the electrooculogram reveals sensitivity of the human outer retina/retinal pigment epithelium to glucose level. Vision Research, 2000, 40, 3447-3453.

Han Y, Bearse MA, Schneck ME, Barez S, Jacobsen C, Adams AJ. Towards optimal filtering of "standard" multifocal electroretinogram (mfERG) responses: Findings in normals and diabetic patients. B J Ophthalmol 88:4;543-540, 2004.

Bearse MA, Han Y, Schneck ME, Adams AJ. Retinal function in normal and diabetic eyes mapped with the slow flash multifocal electroretinogram.  Investigative Ophthalmology and Visual Science, 45:296-304, 2004.

Han Y, Adams AJ, Bearse MA, Schneck ME. Multifocal electroretinogram (mfERG) and short wavelength automated perimetry (SWAP) measures in diabetic eyes with little or no retinopathy. Archives of Ophthalmology. In press February, 2004.

Han Y, Bearse MA, Schneck ME, Barez S, et al. Multifocal electroretinogram (mfERG) delays identify sites of subsequent diabetic retinopathy. Investigative Ophthalmology and Visual Science, 45; 948-954, 2004.

Schneck ME, Bearse MA, Han Y, Barez S, Jacobsen C, Adams AJ "Comparison of mfERG implicit time measures for detecting functional change in early diabetic eye disease"  Documenta Ophthalmologica, submitted March 2004.

Schneck ME, Fortune B, Adams AJ "Changes in the Human ERG in Response to Induced Variations in Blood Glucose" Documenta Ophthalmologica, submitted March 2004.

Bearse MA, Han Y, Schneck ME, Barez S, Jacobsen C, Adams AJ "Local Multifocal Oscillatory Potential Abnormalities in Diabetes and Early Diabetic Retinopathy" Investigative Ophthalmology and Visual Science, submitted March 2004.

Han Y, Schneck ME, Bearse MA, Barez S, Jacobsen C, Jewell NP, Adams AJ "Formulation and Evaluation of a Predictive Model to Identify the Sites of Future Diabetic Retinopathy" Investigative Ophthalmology and Visual Science, submitted April 8, 2004.

Links

The Adams Diabetes Research Website

Back to Faculty Directory page