Related Experiment Videos
Elliptical features of the human optic nerve head
American Journal of Optometry and Physiological Optics
|March 1, 1987
Summary
This study analyzed optic nerve head shapes in 396 normal eyes, finding they are typically elliptical. The long axis averages 11.5% longer than the short axis, with a 10-degree tilt toward the midline.
Area of Science:
- Ophthalmology
- Optometry
- Anatomy
Background:
- The optic nerve head's shape is crucial for diagnosing various ocular conditions.
- Understanding the normative variations in optic nerve head morphology is essential for accurate clinical assessment.
Purpose of the Study:
- To quantify the degree of ellipticalness and orientation of the optic nerve head in a normal population.
- To establish frequency distributions for optic nerve head ellipticity.
Main Methods:
- Acquisition of ocular fundus photographs from 396 normal eyes.
- Digitization of nerve head circumferences and fitting of elliptical models.
- Determination of major and minor axis lengths and major axis orientation.
Main Results:
- The optic nerve head exhibits a consistent elliptical shape in normal eyes.
- The major axis is, on average, 11.5% longer than the minor axis.
- The major axis shows an average tilt of 10 degrees towards the midline.
- Elschnig type III nerve heads demonstrate higher ellipticity values compared to type II.
Conclusions:
- The optic nerve head is predominantly elliptical in shape within the normal population.
- Specific quantitative parameters for ellipticity and orientation have been established.
- Findings may aid in differentiating normal variations from pathological changes, particularly concerning Elschnig classifications.