Document Detail


The effect of proximity on open-loop accommodation responses measured with pinholes.
MedLine Citation:
PMID:  20629958     Owner:  NLM     Status:  In-Process    
Abstract/OtherAbstract:
Open-loop accommodation levels were measured in 41 healthy, young subjects using a Shin-Nippon SRW-5000 autorefractor in the three viewing conditions: a small physical pinhole pupil (SP), an optically projected pinhole in Maxwellian view (MV) and in the dark (DF). The target viewed through the pinholes was a high-contrast letter presented at 0 D vergence in a +5 D Badal lens system. Overall, results showed that SP open-loop accommodation levels were significantly higher than MV and DF levels. Subjects could be divided into two distinct subgroups according to their response behaviour: responders to the proximal effect of the small physical pinhole (SP accommodation > MV accommodation) and non-responders to the proximal effect of the small physical pinhole (SP accommodation approximately MV accommodation). Correlation analysis demonstrated that open-loop accommodation for both pinhole conditions was correlated with DF for the responders, while for the non-responders SP and MV accommodation were correlated, but were not related to DF accommodation. This suggests that under open-loop conditions some individuals' accommodation levels are mainly affected by proximal and cognitive factors (responders) while others are guided primarily by the presence of the more distal target (non-responders). In conclusion, MV reduces the proximal effect of the physical pinhole and produces open-loop accommodation responses which are more consistent than SP and DF responses.
Authors:
K A Morrison; D Seidel; N C Strang; L S Gray
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Ophthalmic & physiological optics : the journal of the British College of Ophthalmic Opticians (Optometrists)     Volume:  30     ISSN:  1475-1313     ISO Abbreviation:  Ophthalmic Physiol Opt     Publication Date:  2010 Jul 
Date Detail:
Created Date:  2010-07-15     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8208839     Medline TA:  Ophthalmic Physiol Opt     Country:  England    
Other Details:
Languages:  eng     Pagination:  365-70     Citation Subset:  IM    
Affiliation:
Vision Sciences, Glasgow Caledonian University, Cowcaddens Road, Glasgow G4 0BA, UK. kmor@gcal.ac.uk
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