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Correlation of nerve head and blind spot elliptical features
1School of Optometry, University of Waterloo, Ontario, Canada.
American Journal of Optometry and Physiological Optics
|January 1, 1988
Summary
The shape of the optic nerve head does not accurately predict the elliptical shape of the corresponding blind spot. Blind spots were found to be significantly more elliptical than nerve heads, with negligible correlation between their shapes.
Area of Science:
- Ophthalmology
- Optometry
- Medical Imaging
Background:
- The optic nerve head (ONH) and its associated blind spot are crucial structures in visual field testing.
- Understanding the geometric relationship between the ONH and blind spot is important for interpreting visual field defects.
Purpose of the Study:
- To investigate the degree to which the elliptical shape of the optic nerve head is reflected in the shape of the corresponding blind spot.
- To quantify the correlation between the ellipticity of the ONH and the blind spot.
Main Methods:
- Elliptical fitting was performed on images of 129 optic nerve heads.
- Corresponding blind spots were analyzed using visual field testing data (Goldmann perimetry).
- The ratio of the long axis to the short axis was calculated for both structures to quantify ellipticity.
Main Results:
- Blind spots exhibited 2 to 3 times greater ellipticity compared to the optic nerve heads.
- A negligible correlation was observed between the ellipticity ratios of the nerve heads and blind spots (Pearson r = 0.07 for Goldmann 1-2 and r = 0.18 for Goldmann 1-4).
Conclusions:
- The elliptical nature of the optic nerve head is a poor predictor of the blind spot's ellipticity.
- Ocular structures beyond the optic nerve head likely influence the final shape of the blind spot.
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