Effect of manipulating the vergence/accommodation and image size mismatches of the ±2D flipper test on the frequency and precision of accommodative facility

Vera, Jesús; Redondo, Beatriz; Martínez‐Tovar, José Miguel; Molina, Rubén; Koulieris, George A.; Allen, Peter M.; Jiménez, Raimundo

Abstract

Purpose
The ±2.00 D accommodative facility test presents several limitations, including the lack of objective information and inherent characteristics such as vergence/accommodative conflict, change in apparent size of the image, subjective criteria for judging blur and motor reaction time. By using free-space viewing conditions and an open-field autorefractor to monitor the refractive state, we examined the impact of manipulating these factors on the qualitative and quantitative assessment of accommodative facility.

Methods
Twenty-five healthy young adults (24.5 ± 4.5 years) took part in this study. Participants performed three accommodative facility tests (adapted flipper, 4D free-space viewing and 2.5D free-space viewing) under both monocular and binocular conditions in random order. A binocular open-field autorefractor was used to assess the accommodative response continuously, and these data were used to characterise accommodative facility quantitatively and qualitatively.

Results
There were statistically significant differences between the three testing methods both quantitatively (p < 0.001) and qualitatively (p = 0.02). For the same accommodative demand, a lower number of cycles was obtained for the adapted flipper condition in comparison with the 4D free-space viewing test (corrected p-value < 0.001, Cohen's d = 0.78). However, this comparison did not reach statistical significance for qualitative measures of accommodative facility (corrected p-value = 0.82, Cohen's d 0.05).

Conclusions
These data provide evidence that the qualitative assessment of accommodative facility is not influenced by the inherent limitations of the ±2.00 D flipper test. The use of qualitative outcomes by incorporating an open-field autorefractor allows examiners to increase the validity of the accommodative facility test in both clinical and research settings.

Citation

Vera, J., Redondo, B., Martínez‐Tovar, J. M., Molina, R., Koulieris, G. A., Allen, P. M., & Jiménez, R. (2023). Effect of manipulating the vergence/accommodation and image size mismatches of the ±2D flipper test on the frequency and precision of accommodative facility. Ophthalmic and Physiological Optics, 43(4), 660-667. https://doi.org/10.1111/opo.13136

• Journal Article Type: Article
• Acceptance Date: Mar 21, 2023
• Online Publication Date: Apr 1, 2023
• Publication Date: Jul 31, 2023
• Deposit Date: Jul 13, 2023
• Publicly Available Date: Aug 5, 2023
• Journal: Ophthalmic and Physiological Optics
• Print ISSN: 0275-5408
• Electronic ISSN: 1475-1313
• Publisher: Wiley
• Volume: 43
• Issue: 4
• Pages: 660-667
• DOI: https://doi.org/10.1111/opo.13136
• Public URL: https://durham-repository.worktribe.com/output/1168540