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Michael Ntodie, Kathryn J Saunders, Julie-Anne Little; What happens to the accommodative response after sustained near tasks in young uncorrected hyperopes?. Invest. Ophthalmol. Vis. Sci. 2018;59(9):2953.
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© ARVO (1962-2015); The Authors (2016-present)
Uncorrected hyperopia places an extra demand on the accommodative system for near tasks and yet we consider low levels of hyperopia unnecessary to correct in childhood. This study investigated how uncorrected hyperopia influences accommodative accuracy during performance of sustained near tasks.
Binocular assessment of sustained accommodative performance was carried out using photorefraction (PowerRefractor 3™, PlusOptix, Germany) in children with (n=21) and without hyperopia (n=60) aged 7-10 years. Hyperopia was determined by cycloplegic refraction, and defined as >/= +2.00D and anisometropia ≤1D). Binocular accommodation measures were obtained while children engaged in two near tasks at 25cm: an ‘active’ (high demand) task (reading small print on an Amazon Kindle), and a ‘passive’ (low demand) task (watching animated movie on an LCD screen) during a 10-minute period. Other baseline clinical measures were also assessed. Individual accommodative response slopes were obtained from sampling photorefraction data after 10 minutes and averaging response from right and left eyes. Calibration routines were also incorporated into the photorefraction data. A perfect response slope is equal to one.
The mean ±SD age of participants was 8.5±1.09 years, and all completed the tasks. There were no significant differences in age between groups (t=-1.02, p=0.310). Mean (±SD) spherical equivalent refractive error was 3.1±1.42D (range 2.00-7.44D) for the hyperopic group and 0.92±0.57(-0.69-1.88) for the emmetropes. There was increased response slope with the active task compared to the passive task for both hyperopes (1.1±0.34 vs 0.86±0.41 respectively) and emmetropes (0.93±0.22 vs 0.72±0.25) (t=5.72, p<0.001). Similarly, the difference in response slopes was statistically significant between hyperopes and emmetropes (F(1,79)=4.45, p=0.038) for the high demand task. However, there was no difference observed in the response slopes in the two groups for the low demand task (F(1,78)=0.31, p=0.064).
Uncorrected hyperopes exhibited increased accommodative response to a sustained high demand task compared to emmetropes. This could be due to increased accommodative-convergence in the hyperopic group. The stability of this response, the vergence response, and the role of optical correction need to be investigated.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.
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