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Sonisha Neupane, Yifei Wu, Vidhyapriya Sreenivasan, Don Lyon, Katie Connolly, T. Candy; Comparison of Vergence and Accommodation Responses of Strabismic and Non-strabismic hyperopic, and emmetropic children. Journal of Vision 2018;18(10):940. doi: https://doi.org/10.1167/18.10.940.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: Accommodative esotropia is associated with significant hyperopia in childhood. Only about 20% of these hyperopes develop esotropia however. What are the factors differentiating the two groups? In this study, we compared accommodation and vergence behavior of strabismic hyperopic, non strabismic hyperopic and emmetropic children. Methods: Simultaneous Purkinje image tracking and eccentric photorefraction (PlusOptix PowerRefractor) were used to record eye alignment and refractive state of age-matched strabismic hyperopes (N=7, Mean Age: 4.36 years, mean cycloplegic refraction: +6.25 D), non-strabismic hyperopes with no optical correction (N=7, Mean Age: 4.61 years, mean cycloplegic refraction: +3.18 D) and emmetropic children (N=10, Mean Age: 5.53 years, mean cycloplegic refraction: +1.13 D). Subjects viewed naturalistic images at 80 & 33cm distances in monocular and binocular viewing conditions. The mean accommodation and alignment postures at the two distances were determined for each participant and compared across groups. Results: The emmetropic group (E) exhibited typical relationships between accommodation(A) and vergence(V) at these distances in binocular conditions (Change: A = 2.01D±0.57, V = 8.47pd±3.35). The hyperopic groups exhibited a range of behaviors. On average non-strabismics (NS) were similar to the emmetropes even in the absence of optical correction (Change: A = 1.64±0.70D, V = 9.53±1.5pd), while the strabismic group (S) were misaligned for the same demands (Change: A = 1.13±1.94D, V = 4.92±9.66pd),). In monocular conditions, the emmetropes exhibited typical response coupling (mean 4.17pd/D of accommodation), which agreed well with the NS group (mean 5.80pd/D of accommodation). Counter to common expectation, the strabismic group did not all exhibit high coupling ratios (mean 3.82 pd/D of accommodation). Conclusion: Simultaneous measures of accommodation and vergence provide critical information about the conflict between coupled vergence and accommodation responses in hyperopes. The data suggest these individuals display an unexpected range of behaviors from fully typical to decompensated convergent deviation.
Meeting abstract presented at VSS 2018
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