Professor Gunilla Haegerstrom-Portnoy

School of Optometry

Aging and vision: relation to performance

A large longitudinal population study of vision function changes with aging and their relationship to general health and activities of daily living has been on-going for the last 10 years. The purpose is to assess vision function comprehensively using a battery of vision tests emphasizing low contrast function and to evaluate the relationship between vision function and visual performance as well as subjective complaints and general health and functioning. An additional purpose was to determine if nonstandard vision tests predict future loss of vision. The second phase of this National Eye Institute (NEI) sponsored study asked the following: How does vision function change with age? How do subjective complaints of vision related activities change with age? Is age alone a good predictor? How does performance of vision related tasks such as reading and driving change with age? Three phases of testing have been completed, with 902 observers the first time, 596 the second time, and 450 of the survivors the third time. The time period between tests was 4.4 and 3 years, respectively. Each vision function ages at its own rate; some functions are hardly affected, while others show 15-18 times worse performance in the oldest age groups. Many elderly are visually impaired under conditions of reduced contrast, reduced lighting or in the presence of glare conditions more often encountered in daily life. This is true even for those with good standard high contrast visual acuity. The sensory losses also results in functional impairment, e.g. face recognition and driving performance.

Neural organization of the retina: abnormal color vision-achromats

Achromatopsia or rod monochromacy is a stable and rare genetic disorder that results in legal blindness and no color vision. Blue cone monochromacy is an even rarer condition characterized by similar vision problems. An unusually large number of people with achromatopsia - over 100 autosomal recessive achromats and 30 x-linked achromats - participate in these studies. Results from these patients clarify how color vision is processed in normals. Achromats have unusual refractive errors, which may contribute to our understanding of nature vs. nurture in the development of refractive errors. Each group has a distinctly different refractive error profile emphasizing the genetic contributions to refractive errors. A longitudinal study of refractive error and vision development in children with achromatopsia is on-going. These data allow prediction of future vision function in achromats and are also helpful when encountering other children with congenital low vision of other etiologies.

Multi-focal ERG in age-related maculopathy and age-matched normal individuals

Age-related macular degeneration (ARMD) is the leading cause of legal blindness in the US population over the age of 50 years. Despite better understanding of the epidemiology, natural history and pathophysiology of the disorder, there are today no satisfactory methods to longitudinally track changes in retinal function in this disease. The multi-focal ElectroRetinoGram (ERG) is a relatively new method that allows assessment of local retinal areas using an objective test. The results indicate abnormal retinal function in many patients with ARMD even in the early stages. The results have also shown surprisingly strong ability of the multifocal ERG to predict who will go on to lose central vision function from this disease.