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Updated: Aug 7, 2026
05:36
Subjective Refraction Test Using a Smartphone for Vision Screening
Published on: October 18, 2024
Validation of the PowerRefractor for measuring human infant refraction
Pamela J Blade1, T Rowan Candy
1Indiana University School of Optometry, Bloomington, Indiana 47405-3680, USA.
Summary
The PowerRefractor shows promise for infant vision screening, accurately detecting large defocus amounts. However, individual calibration is needed for precise measurements in infants and adults.
Area of Science:
- Ophthalmology
- Pediatric Optometry
- Vision Science
Background:
- Eccentric photorefraction offers rapid, remote refraction and gaze estimation in infants.
- This technique holds potential for widespread use in infant vision screenings and developmental studies.
Purpose of the Study:
- To evaluate the refraction calibration of the PowerRefractor for uncyclopleged infants.
- Assessing the accuracy of this non-invasive method for pediatric vision assessment.
Main Methods:
- Compared PowerRefractor defocus measurements with simultaneous retinoscopy in infants (1-6 months) and adults.
- Validated instrument readings against known defocus induced by trial lenses.
Main Results:
- The PowerRefractor generally measured less than 1 D myopia with neutral retinoscopy.
- Validation functions showed slopes near 1 over a 4D range for both infants and adults.
- Infant slopes were significantly steeper than adult slopes.
Conclusions:
- The PowerRefractor can detect substantial defocus in infants.
- Individual calibration is essential for accurate accommodative accuracy and absolute defocus studies in infants, similar to adult recommendations.
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