1995 Fiscal Year Final Research Report Summary
Study of the mechanism of visual function in incomplete type of congenital stationary night blindness
| Project/Area Number |
06454496
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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 | Nagoya University |
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Principal Investigator |
MIYAKE Yozo Dept.of Ophthalmology, Nagoya Univ, Associate Professor, 医学部, 助教授 (30166136)
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| Co-Investigator(Kenkyū-buntansha) |
HORIGUCHI Masayuki Dept.of Ophthalmology, Nagoya Univ, Assistant Professor, 医学部, 講師 (70209295)
TERASAKI Hiroko Dept.of Ophthalmology, Nagoya Univ, Assistant Professor, 医学部, 講師 (40207478)
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| Project Period (FY) |
1994 – 1995
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| Keywords | CSNB / Complete type / Incomplete type / rod bipolar cell / rod b-wave / STR / SRCI / Locus of night blindness |
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| Research Abstract |
We studied the mechanism of visual function in complete and incomplete type of congenital stationary night blindness (CSNB) with the following results.
1.Locus of night blindness
Using full-field stimuli with light intensities ranging from near absolute threshold to bright, ERG intensity series from patients with complete and incomplete CSNB and from normal subjects were recorded. Neither the rod b-wave nor the STR was recordable from patients with complete CSNB.In the incomplete CSNB,the STR was clearly recordable, although the absolute threshold was elevated slightly. The b-wave stimulus threshold was not elevated, and the b-wave amplitude near threshold was normal. The peak time of the STR was delayd by approximately 80 msec, whereas that of b-wave was normal.
Above results suggest that the locus of the night blindness of the complete type may lie in the rod bipolar cell, while that of incomplete type may lie proximal to the rod bipolar cell.
2.Rod-cone interaction
Dark-adapted rods have a suppressive effect on cone response (SRCI). This phenomenon was applied to analyze the pathological mechanism of CSNB.Our results indicated that SRCI is normal in both complete and incomplete CSNB,but in some cases, SRCI is absent because of localized retinal dysfunction.
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