Abstract
Purpose: :
To evaluate the effect of negative spherical aberration (NSA) on depth of focus (DoF) according to the patient’s specific pupil size under scotopic distance and photopic near conditions.
Methods: :
Dominant eyes of 19 healthy subjects were evaluated. The subjects had their pupil measured in scotopic distance and photopic near conditions and examined following cycloplegia with an adaptive optics visual simulator (AOVS). The device corrected the aberrations and induced variable magnitudes of NSA (0.3 - 0.9µm) while the subject was tested with Sloan letters. The highest magnitude of NSA that maintained 20/20 visual acuity was used to test DoF range in steps of 0.5 D, using scotopic distance and photopic near pupil diameters obtained by the pupillometry.
Results: :
The mean DoF range was higher with NSA and photopic near pupil diameter than with the scotopic distance pupil (2.53 +/-0.56D vs. 1.97 +/-0.65D; P<0.05). The mean of the highest amount of NSA tolerated while maintaining 20/20 VA was similar in each of the scotopic pupil size subgroups (-0.39m vs. -0.4m; P=0.82). There was a shift in DoF range toward myopia when shrinking the pupil diameter and maintaining the NSA (average: 0.79D)
Conclusions: :
AOVS can help determine the tolerance to differing amounts of NSA. The specific pupil size was not associated with the ability to tolerate NSA. There was an increase and shift toward myopia in DoF range just by changing the pupil size to the photopic near condition, while testing with the maximum tolerable NSA.
Keywords: clinical (human) or epidemiologic studies: treatment/prevention assessment/controlled clinical trials • refractive surgery: optical quality • accessory optic system/pretectum