Amplify EyeCare Chattanooga Logo
Authors
Ghosh, Atanu; Collins, Michael J.; Read, Scott A.; Davis, Brett A.; Chatterjee, Payel

Axial Elongation Associated with Biomechanical Factors during Near Work

publication date
Category
see more

Abstract/Introduction

Purpose 

To investigate the changes occurring in the axial length, choroidal thickness, and anterior biometrics of the eye during a 10-minute near task performed in downward gaze.

 

Methods 

Twenty young adult subjects (10 emmetropes and 10 myopes) participated in this study. To measure ocular biometrics in downward gaze, an optical biometer was inclined on a custom-built height- and tilt-adjustable table. Baseline measures were collected after each subject performed a distance primary gaze control task for 10 minutes to provide washout period for previous visual tasks before each of three different accommodation/gaze conditions. These other three conditions included a near task (2.5 diopters [D]) in primary gaze and a near (2.5 D) and a far (0 D) accommodative task in downward gaze (25 degrees), all for 10 minutes’ duration. Immediately after and then 5 and 10 minutes from the commencement of each trial, measurements of ocular biometrics (e.g., anterior biometrics, axial length, choroidal thickness, and retinal thickness) were obtained.


Conclusion/Results

Results 

Axial length increased with accommodation and was significantly greater for downward gaze with accommodation (mean ± SD change, 23 ± 13 μm at 10 minutes) compared with primary gaze with accommodation (8 ± 15 μm at 10 minutes) (p < 0.05). A small amount of choroidal thinning was also found during accommodation that was statistically significant in downward gaze (13 ± 14 μm at 10 minutes; p < 0.05). Accommodation in downward gaze also caused greater changes in anterior chamber depth and lens thickness compared with accommodation in primary gaze.

 

Conclusions 

Axial length, choroidal thickness, and anterior eye biometrics change significantly during accommodation in downward gaze as a function of time. These changes seem to be caused by the combined influence of biomechanical factors (i.e., extraocular muscle forces, ciliary muscle contraction) associated with near tasks in downward gaze.


Contact Us To Amplify Your EyeCare

Working Hours

Monday - Thursday
8:00 am - 5:15pm
friday-sunday
Closed
Location
1043 Executive Drive Suite #101 Hixson, TN 37343
Website Accessibility Policy
Safety protocols page
phone-handsetarrow-uparrow-right linkedin facebook pinterest youtube rss twitter instagram facebook-blank rss-blank linkedin-blank pinterest youtube twitter instagram