Abstract
Purpose: :
To assess symptom type and severity following 65 minutes of 3-D television viewing in young adults with and without their binocular vision corrective spectacle lenses (BVCSL).
Methods: :
35 adult subjects (ages 32.2+/- 4.4 yrs) were pre-screened out of 98 individuals to have the highest symptom/asthenopia scores following 65 minutes of 3-D television viewing with their habitual distance spectacle correction. They did not have amblyopia, strabismus, or ocular disease. These 35 individuals were then retested as they watched 3-D television for 65 minutes at a distance of 2.7m (which reduced the mismatch between accommodation and vergence). Retesting was conducted in a counterbalanced manner with either their habitual distance corrective spectacles or their BVCSL; the latter corrected/compensated for their exophoria with base-in prisms, their esophoria with base-out prisms (combined with 0.75D yoked prisms), and their vertical phoria with vertical prisms. A 4-point symptom-rating scale questionnaire (0=mild and 3=severe) was used to assess 11 symptoms (e.g., blur, diplopia, etc.) related to visual fatigue/visual discomfort. It was administered at 4 equal intervals during each 65 minute test session.
Results: :
There was a significant (p<0.001) overall reduction in the asthenopia score from 21.9 without, to 9.5 with, the BVCSL at the end of the session, as well as at each periodic assessment interval (p<0.001). The asthenopia score increased progressively without the BVSCL (p<0.001), but remained constant with the BVSCL (p=0.12). The primary symptoms were eye strain, dry eye, eye soreness, and headache without the BVSCL.
Conclusions: :
Correction of one's phoria/vergence-based binocular vision imbalance resulted in a significant reduction in asthenopia both during and immediately following 65 minutes of 3-D television viewing. An individual's phoria-based binocular vision imbalance should be corrected/compensated with appropriate prisms prior to prolonged viewing of 3-D television displays to optimize the interactions between vergence and accommodation, thereby resulting in reduced/minimal asthenopia/visual fatigue.
Keywords: binocular vision/stereopsis • spectacle lens