To study the effectiveness of yellow-tinted lenses and low-plus lenses, separately and together, at reducing eye related symptoms when using a computer.
We will recruit 40 participants, ages 18-40, with near emmetropia or contact-lens corrected refractive error. They will be subjected to the following five conditions while reading on a LCD desktop monitor under glare conditions typical of a work environment:
Yellow tint only
Neutral-density gray tint only (compare to yellow)
+0.50 D sphere clear lenses
+0.50 D sphere with yellow tint
Plano sphere untinted lenses with anti-reflective coating (control)
Subjective evaluation of type of symptom sensation
EMG from orbicularis
Accommodative response – magnitude and variability
Our hypothesis is that yellow tint will be beneficial as it is known to absorb high-energy blue light which may contribute to squinting and glare, especially when using fluorescent lights. Glare has been shown to create external (dry eye-like) symptoms and the eyelid squint response can be sensitively measured with electromyography (EMG).
We further hypothesize that the +0.50 lens power, by reducing accommodative demand, will also reduce the internal symptoms (ache and pain) that have been shown to be related to accommodative stress and will also result in decreased accommodative fluctuations.
This study will determine if the measured effects are significantly different from plano (no optical power) control lenses, which will have an antireflective coating to avoid unwanted reflections on the lenses.