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Does Adjusting for Head Position Matter in Fundus Photography? (P11-10.005)
David Hale1, Dipakshi Tare2, Kemar Green1
1Johns Hopkins Hospital.
Neurology
|February 20, 2025
Summary
Head position impacts ocular torsion measurements in fundus photos. While significant head tilts alter disc foveal angle (DFA), standard upright head positioning shows no significant effect on DFA measurements.
Area of Science:
- Ophthalmology
- Neuroscience
- Biomedical Engineering
Background:
- Ocular torsion, measured by disc foveal angle (DFA) on fundus photos, can be influenced by head position via the vestibulo-ocular response (ocular counter-roll).
- Routine fundus photography often lacks controlled head positioning, potentially affecting torsion measurements.
Purpose of the Study:
- To investigate the impact of different head positions on the measurement of ocular torsion using disc foveal angle (DFA) in fundus photography.
Main Methods:
- Fundus photos were captured from 10 participants under three head position conditions: standard (unadjusted chin rest), upright chin rest, and chin rest tilted 10° left/right.
- Head position was quantified using a gyroscope.
- Disc foveal angle (DFA) was measured and compared across the three conditions.
Main Results:
- A significant difference in DFA was observed when the head was tilted 10° compared to the upright position (p<0.0001).
- The standard head position exhibited a larger average head tilt (1.31°) than the upright position (0.07°).
- No significant difference in DFA was found between the standard and upright head positions (p=0.62).
Conclusions:
- Head positioning during fundus photography can influence DFA measurements.
- Large head tilts significantly alter DFA, whereas standard, upright head positioning does not yield significant changes in DFA.
