| Project/Area Number |
17591850
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Ophthalmology
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| Research Institution | Iwate Medical University |
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Principal Investigator |
MACHIDA Shigeki Iwate Medical University, School of Medicine, Associate Professor, 医学部, 助教授 (30285613)
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| Co-Investigator(Kenkyū-buntansha) |
NABESHIMA Takashi Iwate Medical University, School of Medicine, Assistant Professor, 医学部, 講師 (20364359)
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| Project Period (FY) |
2005 – 2006
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| Project Status |
Completed (Fiscal Year 2006)
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| Budget Amount *help |
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2006: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 2005: ¥2,400,000 (Direct Cost: ¥2,400,000)
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| Keywords | electoretinogram / ERG / inner retina / retinal ganglion cell / glaucoma / diabetic retinopathy / macular hole / photoreceptor / 視神経障害 / photopic negative response / 多局所網膜電図 / 錐体ERG |
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| Research Abstract |
A. Results based on animal experiments
1. ERG changes following the optic nerve damage
After the optic nerve was impaired by applying diathermy around the optic nerve head in cats, we investigated ERG changes with time. The s-wave of the mfERG disappeared 1 week after the damage. On the other hand, the photopic negative response (PhNR) significantly deteriorated 1 month after the damage. This indicates that the mfERG detects functional changes earlier than the full-field ERG after the optic nerve damage.
2. Functional changes of the inner retina associated with photoreceptor degeneration
We found that an interesting change of the inner retinal function in rats with inherited photoreceptor degeneration. We recorded ERGs from Royal College of Surgeons (RCS) rats. The third-order neuronal response was preserved despite progressive loss of the b-wave. The results indicate that the third-order neuronal response progressively make contribution to shaping the ERG with advancing photoreceptor dege
… More
neration.
B. Clinical application of the s-wave and PhNR
1. Diabetic retinopathy
Oscillatory potentials (OPs) have been used as a functional indicator for early diabetic retinopathy. This indicates that dysfunction of the inner retina occurs at the early stage of diabetic retinopathy. Therefore, we compared clinical significance to detect early change of the inner retinal function in early diabetic retinopathy between the OPs and PhNR. The results demonstrated that the OPs had higher sensitivity and specificity than the PhNR, indicating that the OPs are better indicator to detect early diabetic retinopathy than the PhNR.
2. Macular hole surgery
Indocyanine green (ICG) has been used to stain the inner limiting membrane during macular hole surgery. Animal studies have demonstrated that ICG injures retinal ganglion cells (RGCs) at high concentration. We compared the full-field and mf ERG between operated eyes and contralateral normal (control) eyes. Although there was no significant difference in the a-and b-waves between the operated and control eyes, the PhNR was significantly deteriorated. The s-wave of the mf ERG transiently reduced for 1 month after the surgery but returned to the pre-operated amplitude. These indicate that the PhNR and s-wave detect subclinical damage to RGCs induced by macular hole surgery.
3. Glaucoma
We recorded full-field cone ERGs using white stimuli in white background (W/W) or red stimuli on blue background (R/B) The PhNR obtained by these stimulus conditions were plotted against visual sensitivity and morphometric parameters of the optic nerve head. The PhNR amplitude was significantly correlated with visual sensitivity, rim area and retinal nerve fiber layer thickness. The R/B ERG has higher correlation coefficients than the W/W ERG These indicate that the PhNR recorded by R/B is better to Less
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