Accommodation and spherical aberration
Purpose: The accommodation response to changing levels of longitudinal spherical aberration (LSA) was measured. The LSA of the eye is known to change from positive to negative as the level of accommodation of the eye increases. However, little is known about the effect of these changes in spherical aberration on the overall accommododation response. Methods: The existing monochromatic aberrations of three young subjects were measured using the objective aberroscope procedure across a range of accommodation levels. LSA was induced through the use of aspheric surface, rigid contact lenses (in-air) positioned over a 5 mm aperture at a distance of 12 mm from the eye. Seven levels of LSA were induced ranging from -3 D and +3 D of LSA. The subjects viewed a high contrast Maltese cross with the right eye at distances of 33 cm and 67 cm in photopic conditions. Measurements of accom~nodationle vel for each LSA condition were made from tlie left (occluded) eye using the Canon Autoref R-1, a free-space objective infra-red optometer. Results: For the three subjects who were tested, negative LSA caused an increased accommodation response and positive LSA a decreased accommodation response. Pooling the data across subjects and test distances, a linear regression on induced LSA versus accommodation response gave: Accommodation response (D) = 0.23 - 0.25 LSA (D) (rz= 0.90). Therefore, for every one dioptre of LSA, there was approximately 0.25 D of accommodation response. Some individual variations occurred and there was some apparent flattening of the slope at the extremes of induced LSA. Conclusions: These findings suggest that the accommodation response of the eye will be influenced by the natural changes in spherical aberration of the eye associated with accommodation and by optical corrections of the eye which induce spherical aberration.
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|Item Type:||Journal Article|
|Additional Information:||For more information, please refer to the journal’s website (see hypertext link) or contact the author. The contents of this journal from 1998 to 2005 can be freely accessed online via the journal’s web page.|
|Subjects:||Australian and New Zealand Standard Research Classification > MEDICAL AND HEALTH SCIENCES (110000) > OPTOMETRY AND OPHTHALMOLOGY (111300)|
Australian and New Zealand Standard Research Classification > MEDICAL AND HEALTH SCIENCES (110000) > OPTOMETRY AND OPHTHALMOLOGY (111300) > Vision Science (111303)
Australian and New Zealand Standard Research Classification > MEDICAL AND HEALTH SCIENCES (110000) > OPTOMETRY AND OPHTHALMOLOGY (111300) > Optical Technology (111302)
|Divisions:||Current > Research Centres > Centre for Health Research|
Current > QUT Faculties and Divisions > Faculty of Health
Current > Institutes > Institute of Health and Biomedical Innovation
|Copyright Owner:||Copyright 1997 Optometrists Association Australia|
|Deposited On:||25 Jan 2008|
|Last Modified:||20 May 2010 02:29|
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