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Y. Wu, B.-C. Jiang; The Effects of Spherical Aberration on Accommodative Response in Different Refractive Groups. Invest. Ophthalmol. Vis. Sci. 2010;51(13):3957.
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© ARVO (1962-2015); The Authors (2016-present)
To compare the effects of spherical aberration on accommodative response between different refractive groups.
The accommodative responses induced by negative lenses from 0 to -5 D with 1 D step were measured with a COAS device for 10 emmetropes (EMs), 13 stable myopes (SMs), and 9 progressing myopes (PMs). Three types of accommodative response were calculated from each subject's wavefront aberration data with his/her natural pupil size. The total accommodative response (tAR) was based on Zernike defocus term. The paraxial accommodative response (pAR) was based on Zernike defocus and spherical aberrations. In addition, we added the spherical aberration at the edge of 3.5 mm pupil to the pAR and defined it as the AR-3.5. This item was used for simulating the measurement obtained from auto-refractor such as Canon R-1.The difference between pAR and tAR, which was called as apparent defocus shift (ADS), was plotted as a function of accommodative response error of tAR (tAE). Each subject's accommodative stimulus-response curve (ASRC) under tAR, pAR, or AR-3.5 condition was fitted by a regression line. We compared the ASRCs and the ADS/tAE curves between the three groups and within each group.
The slope of ASRC was significantly steeper for pAR than for tAR and AR-3.5 in each group (paired sample test, all p < 0.05). Each subject's ASRC data was used to calculate the accommodative error index (AEI, Chauhan & Charman, 1995), which mainly represented the accuracy of accommodative response. The AEI results were not significantly different between tAR, pAR, and AR-3.5 within each group. Under each condition of tAR, pAR, or AR-3.5, the slope of ASRC and the AEI was not significantly different between groups (p > 0.05). The relationship between ADS and tAE for each group was linear (EMs: p = 0.001; SMs: p = 0.004; PMs: p = 0.001). The slope of ADS/tAE was significantly shallower in the PMs (0.3477) than in the EMs (0.5564) and SMs (0.6006) (linear regression comparison, all p < 0.05).
When we use tAR and AR-3.5 to represent the accommodative response, the spherical aberration of the eye has a significant effect on the slope of ASRC, which is consistent with previous studies. However, our results suggest that the spherical aberration does not change the accuracy of accommodation (AEI). In addition, the effect of spherical aberration on the slope of ASRC is less in the PMs than in the EMs and the SMs.
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