Authors
GOWRISANKARAN, SOWJANYA BSOptom, MS; SHEEDY, JAMES E. OD, PhD, FAAO; HAYES, JOHN R. PhD

Eyelid Squint Response to Asthenopia-Inducing Conditions

publication date
June 27, 2011
Category
see more

Abstract/Introduction

Purpose

To study the orbicularis oculi muscle response to asthenopia-inducing conditions.

 

Methods

Twenty subjects (18–36 years) screened for 20/20 vision in each eye participated in the study. Subjects read passages under different asthenopia-inducing conditions. The inducing conditions were glare, low contrast, small font size, refractive error, up gaze, accommodative stress and convergence stress. Surface electromyography (EMG) was used to study the orbicularis oculi response from the right eye. Palpebral fissure height was measured from recorded video images of the right eye. At the end of each condition subjects were asked to rate the severity and type of visual discomfort experienced.


Conclusion/Results

Results

Outcome measures for the asthenopia-inducing conditions were compared with their respective nonstress controls. Repeated measures analysis of variance was used to analyze the data. Refractive error (p = 0.0001), glare (p = 0.0001), low contrast (p = 0.007), small font (p = 0.034), and up gaze (p = 0.001) resulted in a significant increase in EMG power. Refractive error (p = 0.0001) and glare (p = 0.0001) also caused significant reduction in aperture size. Reading a low contrast text caused a reduction in blink rate (p = 0.035), whereas refractive error (p = 0.005) and glare (p = 0.01) caused an increase in blink rate. All conditions induced significant visual discomfort (p < 0.001).

 

Conclusion

Refractive error and glare, which reduce image quality and benefit from eyelid squint, caused increased EMG power, eyelid squint response and increased blink rate. Low contrast and small font, which reduce image quality but do not benefit from eyelid squint, resulted in increased EMG power without changes in aperture size and reduced blink rate (for low contrast). Accommodative and convergence stress (in subjects with normal accommodative and vergence abilities) did not cause changes in EMG power, aperture size or blink rate. These results suggest that contraction of the orbicularis oculi is a part of the asthenopia mechanism related to compromised image quality.


Testimonials


  • I haven't actually used the optometrist side, so my review is limited to the vision therapy offered.  This office was recommended by my occupational therapist for the treatment of my double vision following a stroke.


    Claire A.

  • Love this location. I had a brain injury accident from day one one. All the team make you feel you still important and hope in the horizon after when the medical system fell you miserably. Dr. Ikeda very professional and very understanding about your issue. Two tombs up.


    Jim K.

  • My husband and I were immediately impressed with Dr Ikeda. I was hit by a car while cycling which caused broken bones and three brain injuries. The brain injuries caused double vision. Dr. Ikeda examined my eyes and got me started on vision therapy with his occupational therapist who specializes in vision therapy.  She (Chris) is absolutely great.  I am impressed with the array of tools used to help recover my binocular vision.  I am doing things I never thought were possible (balance boards etc).  Chris pushes me and keeps me motivated. I really enjoy my sessions with her.  The office staff is always friendly and they have a wonderful appointment reminder tool that makes it easy to keep my calendar up to date. I am happy the rehab center at Little Co. of Mary recommended them!!


    Teresa S.

  • The Vision Therapy is handled in a separate office through a different door from the shared waiting room. Chris, the vision therapist, has a wide and varied assortment of tools, equipment and resources to best evaluate and treat most vision issues. After just a few visits, my double vision became easier to control, using exercises developed during the therapy process. It was time well-spent.


    Joe M.

  • I have been coming here since I can remember. I love it here. The staff is so amazing and nice. They explain everything they gonna do and never make you feel rushed. Dr. Ikeda has always been my doctor and I would never want another one. He is the doctor for my whole family and is always asking how everyone is doing. I am also so crazy about picking out my frames and have to try so many and each person who helps me take the time and lets me try them all on. I would never want to go anywhere else! I definitely would recommend this office to anyone looking for a great eye doctor.


    Kayla W.

Blog

Lighting-Assessment---Intensity-1

Lighting as Part of A Low Vision Evaluation

A low vision evaluation is in some ways similar to a regular eye exam, and in other ways entirely different. […]

Read More
josh-applegate-p_KJvKVsH14-unsplash

Can ADD/ADHD be a Vision Problem?

According to a study, approximately 20% of 4.5 million children currently identified as having ADHD may have been misdiagnosed. Furthermore […]

Read More
pexels-monstera-6186146

Are all magnifiers the same? The difference in optics between handheld magnifiers

Hand magnifiers are hand-held devices that can be placed over an object or text to enlarge or magnify what you […]

Read More
see all blogs

Contact Us To Amplify Your EyeCare

Working Hours

Monday - Thursday
8:00 am - 5:15pm
friday-sunday
Closed
Location
16816 Clark Ave, Bellflower, CA 90706, United States
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