1994 Fiscal Year Final Research Report Summary
Development of experimental myopia using a primate model (tree shrews) and the investigation for the mechanisms of myopia.
| Project/Area Number |
05454466
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Ophthalmology
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| Research Institution | Asahikawa Medical College |
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Principal Investigator |
YOSHIDA Akitoshi Asahikawa Medical College, Professor, 医学部, 教授 (70125417)
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| Co-Investigator(Kenkyū-buntansha) |
KANNO Harumi Asahikawa Medical College, Instructor, 医学部, 助手 (20214728)
OGASAWARA Hironobu Asahikawa Medical College, Instructor, 医学部, 助手 (00177106)
ISHIKO Satoshi Asahikawa Medical College, Instructor, 医学部, 助手 (10250565)
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| Project Period (FY) |
1993 – 1994
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| Keywords | experimental myopia / form deprivation / tree shrew / lens autofluorescence / blood-retinal barrier / blood-aqueous barrier |
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| Research Abstract |
To investigate changes in tree shrew eyes, we studied the methodology for measuring (1) axial length, (2) refractive error, (3) ocular fluorescence, and the new computer simulation method to estimate the blood-retinal barrier (BRB). In addition, the fundus features of normal tree shrews were studied by fundus examination and angiography. The normal ocular development in tree shrews was studied to determine the structural and lens autofluorescence changes. In normal tree shrews, we found that with aging the corneal curvature increased, the lens thickened, and the length of the vitreous decreased. These changes occurred rapidly by 100 days after birth, then occurred slowly after 250 days. The degree of lens autofluorescence increased with age. We also investigated a method to induce form deprivation. In immature tree shrews, beginning the day after form deprivation was induced myopic changes were apparent and the vitreous cavity elongated. Both of these changes reached significant levels at 15 days following induction of form deprivation. This tendency changed when the animal reached maturity ; in mature tree shrews the eyes in which form deprivation was induced did not show the myopic changes during the same period. This suggests that susceptibility to form deprivation myopia may decline in mature animals. Lens autofluorescence values and the inward permeability of the BRB increased by 45 days after form deprivation was induced. However, the aqueous values, the indices of the blood-aqueous barrier, did not change. These findings indicate that myopic changes may be closely related to impaired retinal function based on the BRB permeability in tree shrews with form deprivation myopia. Furthermore, increased lens autofluorescence at the same time may indicated ocular homeostatic impairment caused by the development of myopia.
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