VISUAL PERCEPTION LABORATORY

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Project Title: Mesopic Visual Function Assessment And Risk Genotypes For Age-Related Macular Degeneration

Summary

Age-related macular degeneration (AMD) is an eye disease that manifests at older ages. AMD mainly affects central vision, which reduces the ability to read and perform other similar tasks and eventually lead to blindness. There currently is no cure for AMD and the hope is that finding a method for early detection of the AMD disease process, and uncovering the genetic and pathological mechanisms of the disease process, will lead the way to the development of better treatments and potentially a cure. In the last few decades, modern genotyping methodology has been employed in the study of AMD and some genotypes have been identified as high-risk or low-risk genotypes for AMD. In a previous study, we showed a mesopic vision effect; that is, reduced visual function under dim light conditions, in people with no diagnosis and no symptoms but with the AMD high-risk genotypes, indicating mesopic vision may be affected at an early stage. It is possible that the early signs of ARM may be best found in mesopic vision dysfunction. We propose to investigate how individual life styles (drinking, smoking, diet and exercise) relate to altered mesopic visual function associated with genetic risk for AMD. Further, a characteristic of the early stages of AMD is the accumulation of debris and subsequent development of drusen in the retina. This damage to the retinal pigment epithelium (RPE) and retina may produce a functional barrier between the choroid and the RPE-retina, which means there is a general defect of fluid transfer. A previous report showed that acute alcohol consumption exacerbates this barrier defect and when people drank alcohol, visual function was reduced. Interestingly, the effect of drinking on AMD is perplexing: heavy drinking patterns increase the risk of AMD while moderate drinking decreases the risk of AMD. We will also examine whether acute alcohol intake is able to increase the difference in mesopic visual function between AMD high-risk genotype and low-risk genotype groups. The outcomes will enable us to develop a sensitive method to detect subclinical signs of early AMD and potentially help to elucidate alcohol drinking patterns and risk for AMD.

Specific Aims

Aim 1 : To replicate and extend our study that showed an association between AMD genotypes and mesopic visual function (rod/cone CFFs and ERGs) in healthy older adults that have no clinical signs of AMD and to additionally examine whether individual life-styles (e.g., drinking, smoking, diet, exercise) moderate the gene-mesopic vision relation. Hypothesis 1 : People in the group with high-risk genotypes for AMD will have worse mesopic visual function (rod/cone CFFs and ERGs) than those in the group with low-risk genotypes for AMD.
Hypothesis 2 : Those who are heavy drinkers (vs. lighter drinkers), heavy smokers (vs. light or non-smokers), have less healthy diets (vs. healthy diet) and do not exercise regularly (vs. exercise regularly) will have a greater reduction in mesopic visual function in the group with high-risk genotypes for AMD.

Aim 2 : To examine acute alcohol intake will affect the association between AMD genotypes and mesopic visual function (rod/cone CFFs and ERGs) in healthy older adults who have no clinical signs of AMD and to explore whether life-styles moderate the relation. Hypothesis 1 : Acute alcohol intake will significantly reduce mesopic vision function.
Hypothesis 2 : The difference in mesopic visual function measured under the influence of alcohol between groups with high-risk and low risk genotypes for AMD will be greater than that measured without alcohol.
Hypothesis 3 : Those who are heavy drinkers (vs. lighter drinkers), heavy smokers (vs. light or non-smokers), have less healthy diets (vs. healthy diet) and do not exercise regularly (vs. exercise regularly) will have greater alcohol effect to alter the gene-mesopic vision relation.


Volunteers Needed For This Project in About Two Months


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