Gunilla Haegerstrom-Portnoy, OD, PhD, FAAO
Research Interests
Clinical psychophysics and basic aspects of human color vision; binocular vision
Basic studies of chromatic organization of human parafoveal retina. These psychophysical studies address the general issue of chromatic organization of sensitivity control at parafoveal locations as compared with the fovea.
Studies of mechanisms of visual loss with aging. Vision changes with age have been well documented. Previously, the majority of age-related changes in color vision were attributed to a well-known yellowing of the ocular lens. Recent evidence indicates that morphological changes occur in the retina with increasing age. This project is to determine whether neural changes occur in the retina with age, as distinct from changes in preretinal filters (lens and macular pigment), and to test the hypothesis that long-term exposure to visible radiation (light) contributes to neural loss with age.
Clinical psychophysics: Understanding rod monochromatism. Typical total color blindness, achromatopsia or rod monochromatism, is inherited as an automal recessive condition and is thought to result from absence of cone function. Rod monochromats have been used in basic visual studies as models of normal human rod vision and to study rod vision without interference from cone receptors. This project aims to account for the extreme variability of vision function in rod monochromats on the basis of heterogeneity of the retina (in cone density),'variable fixation patterns, and variations in the genotypes. An additional aim is to relate phenotypical behavior (vision characteristics) to genotypes through the use of molecular genetic techniques.
Selected Publications
Haegerstrom-Portnoy G, Verdon W. Transient tritanopia in a blue cone monochromat. Clin. Vis. Sci. 1991; 6(3): 229-240.
Hamer RD, Norcia AM, Day SH, Haegerstrom-Portnoy G, Lewis D, Hsu-Winges C. Comparison of On- and Off-axis photorefraction with cycloplegic retinoscopy in infants. J. Pediatric Ophthalmol. and Strabismus 1992; 29 (4): 232-239.
Haegerstrom-Portnoy G. New procedures for evaluating vision functions in special populations. Opt. & Vis. Sci. 1993; 70 (4): 306-314.
Savage G, Haegerstrom-Portnoy G, Adams AJ, Hewlett S. Age changes in the optical density of human ocular media. Clinical Vision Scienc. 1993; 8: 97-108.
Crognale M, Switkes E, Rabin J, Schneck M, Haegerstrom-Portnoy G, Adams AJ. Application of the spatio-chromatic visual evoked potential to detection of congenital and acquired color vision defiencies. J. Opt. Soc. Am. 1993; 10(8): 1818-1825.