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Bearing fixing: A new computer algorithm method for subjective determination of astigmatism
Andrew Carkeet1, Jia Hao Ng1, Jia Sheng Choo1
1School of Optometry and Vision Science, Queensland University of Technology, Brisbane, Queensland, Australia.
Summary
Bearing fixing, a novel computer-controlled method, accurately determines astigmatism compared to traditional methods. While slightly more variable, it offers a feasible approach for precise vision correction.
Area of Science:
- Ophthalmology
- Optometry
- Vision Science
Background:
- Astigmatism is a common refractive error affecting visual acuity.
- Accurate subjective refraction is crucial for effective vision correction.
- Conventional methods like Jackson crossed-cylinder refraction have limitations.
Purpose of the Study:
- To introduce and explain the principles of bearing fixing, a new computer-controlled subjective astigmatism measurement technique.
- To compare the efficacy and precision of bearing fixing against the established Jackson crossed-cylinder refraction method.
Main Methods:
- The bearing fixing procedure and its underlying principles were detailed.
- Astigmatism was measured twice in 20 visually normal participants using both bearing fixing and Jackson cross-cylinder methods.
- Visual acuity was assessed after refractive correction with each method.
Main Results:
- Bearing fixing successfully yielded results for all participants.
- Mean cylinder magnitude was marginally higher with bearing fixing (0.05D) but vector analysis showed no significant difference in astigmatism compared to cross-cylinder.
- Bearing fixing exhibited higher test-retest variability (p < 0.05), though visual acuity outcomes did not differ significantly between methods.
Conclusions:
- Bearing fixing is a viable method for subjective astigmatism determination.
- Potential enhancements exist to improve the speed and precision of the bearing fixing technique.
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