Optics for Low Vision Enabling


Jörgen Gustafsson


IKDC seen through an eye with cental scotomaFor people with central visual field loss, eccentric vision is all that they have to rely on. Even for those who learn how to correctly utilize their eccentric vision, it will never be as good as the central for two entirely different reasons: the off-axis optics of the eye can result in large refractive errors, and the low function of the peripheral retina. This thesis deals with the first of these factors: how to study and correct the eccentric aberrations in people with low vision by measuring the optics of their eyes, correcting the aberrations, particularly astigmatism, and evaluating improvements in visual functions.

The individual variations are large for both astigmatism and higher order aberrations such as coma. The main results of this research show that visual improvements through eccentric corrections are possible in spite of the retina’s poor function outside of the macula.

Eccentric optical correction affects both resolution and detection capacities. A person’s visual ability can also be influenced by their awareness and training of eccentric viewing.

All in all, this thesis opens the door to a large area of research, one that is particularly important as the number of elderly people is growing and, as a result, increasing the number of people who are developing macular degeneration. The hope is that it will be possible to develop more and better evaluation methods as well as refractive corrections for eccentric vision and that it will be possible to study separate aspects of visual function in more detail. In so doing, we can increase understanding for how different diseases of the eye affect a variety of visual abilities. It is also essential that the examinations and improvements in the future involve more people than those with large central visual field loss and conscious eccentric viewing, as well as that the results find their application in clinical settings.

Thesis without appendices (pdf 1 MB)

Appendices (pp. 75-148) (pdf 2.7 MB)

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