The effects of panretinal photocoagulation on the primary visual cortex of the adult monkey

Joanne A. Matsubara, Dawn Y. Lam, Ronald E. Kalil, B'Ann T. Gabelt, T. Michael Nork, Dan Hornan, Paul L. Kaufman, Leonard M. Parver

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Abstract

Purpose: To determine the effects of panretinal photocoagulation (PRP) on the levels of cytochrome oxidase (CO), Zif268, synaptophysin, and growth-associated protein 43 (GAP-43) in the primary visual cortex of adult monkeys. Methods: Ten adult primates underwent unilateral argon laser PRP with instrument settings at 300 to 500 μm spot diameter, 200 to 500 mW power intensity, and 0.1 to 0.2 second duration, causing moderate to severe burns in the peripheral retina. At 20 hours, 12 days, 6 months, and 13 months after laser treatment, the visual cortex was assessed histologically for CO and immunohistochemically for Zif268, synaptophysin, and GAP-43. Results: PRP resulted in transneuronal changes in the relative distributions of CO, Zif268, synaptophysin, and GAP-43 in the primary visual cortex. CO activity was relatively decreased in the lasered eye's ocular dominance columns at 12 days post-PRP, with recovery by 13 months post-PRP. The level of Zif268 was dramatically decreased in the lasered eye's ocular dominance columns at 20 hours post-PRP, with gradual recovery by 13 months post-PRP. Levels of synaptophysin and GAP-43 immunoreactivity were increased in both the lasered and the nonlasered eyes' ocular dominance columns at 6 months post-PRP. Conclusion: PRP treatment results in metabolic activity changes in the visual cortex of the adult monkey. These changes are followed chronologically by spatial redistribution of synaptophysin and GAP-43, neurochemicals known to play a role in cortical plasticity. This study demonstrates, for the first time, that PRP as used in the treatment of diabetic retinopathy results in a redistribution of neurochemicals in the adult monkey visual cortex. Such changes may help explain the anomalous visual functional loss often reported by patients after PRP.

Original languageEnglish (US)
Pages (from-to)33-43
Number of pages11
JournalTransactions of the American Ophthalmological Society
Volume99
StatePublished - Dec 1 2001

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ASJC Scopus subject areas

  • Ophthalmology

Cite this

Matsubara, J. A., Lam, D. Y., Kalil, R. E., Gabelt, BA. T., Nork, T. M., Hornan, D., Kaufman, P. L., & Parver, L. M. (2001). The effects of panretinal photocoagulation on the primary visual cortex of the adult monkey. Transactions of the American Ophthalmological Society, 99, 33-43.