Age-related maculopathy and macular degeneration : New diagnostic and therapeutic procedures

University dissertation from Linköping : Linköpings universitet

Abstract: Age-related maculopathy (ARM) may progress into age-related macular degeneration (AMD), which is often disastrous to near vision and reading. Currently used treatment is generally not successful in a long-term perspective. Therefore, searching for an early detection of functional disturbances as well as for prophylactic treatment appears important.Colour contrast sensitivity was measured in patients with soft drusen maculopathy (early ARM). No deterioration in visual function was observed with conventional tests. A highly significant elevation (p<0.001-0.0001) of thresholds for all three colour axes was found, indicating an impairment of retinal function. A tendency towards a bimodal distribution was seen, suggesting a subgroup with a more prominent decrease in foveal sensitivity and possibly at higher risk of progression into the exudative form of the disease. Colour contrast sensitivity appears to be a more sensitive measure of early functional disturbances of the retina than provided by the currently used tests.Contrast sensitivity was measured peripheral to an absolute central scotoma in patients with AMD and was found to be significantly lower (p<0.001) than In normals at the same degree of eccentricity. This finding may explain the variations in the need for magnification in low vision patients with identical visual acuity for achieving the same visual performance.A new system for evaluating paramacular function and establishing the most suitable area for eccentric viewing was designed. The method facilitates the procedure of teaching and training the patient to use the eccentric viewing technique successfully. Reading speed increased significantly (p<O.OOl) with significantly fewer one-hour training sessions (p<O.OOl) than needed with the current training method.In a prospective, randomised study, patients with early ARM were treated with green argon laser photocoagulation perifoveally over the drusen area. Parameters such as visual acuity, colour contrast sensitivity and central visual field were unchanged at the 12-month follow-up. The total drusen area decreased significantly (p<0.0001) after laser photocoagulation over a period of 12 mOnths. No complications were noticed. In a matched control group, the area of drusen tended to increase, and there was a significant difference {p<O.OOl) in drusen area between the two groups after 12 months. In the control group, mean visual acuity (p=0.008) and colour contrast sensitivity along the tritan axis {p=0.044) decreased, and three patients advanced to the exudative stage of AMD during follow-up. The results seem to indicate a promising prophylactic potential of the treatment.

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