Short-Term Monocular Deprivation Shifts Sensory Eye Dominance at 3 Frequencies

Sensory eye dominance resulting from short-term monocular deprivation is not dependent on test spatial frequency, according to a study published in Eye and Vision. These findings may be instrumental in treating adults with binocular vision disorders. 

Researchers enrolled 10 participants (mean [SD] age, 24.7 [1.7] years; 4 men) in an analysis to investigate the effect of short-term monocular deprivation on test spatial frequency. Participants were deprived of sight in their dominant eye for 2.5 hours using a translucent patch. Investigators obtained interocular contrast ratio using a binocular orientation combination task. The effects of monocular deprivation on balance point were evaluated at baseline and at 3, 6, 9, and 30 minutes following deprivation.

At baseline, balance point was attained when the dominant eye’s contrast reached 46.59±0.29%, 42.30±0.51%, and 40.92±0.40% at 0.5, 4, and 6 cycles per degree (c/d) spatial frequencies, respectively. After deprivation, 33.00±0.11%, 29.91±0.32%, and 30.07±0.49% contrasts, at the same frequencies, respectively, were needed to balance the 50% contrast of the non-dominant eye, according to the report. 

Time session (F_[1.86,16.76], 33.09; P <.001) was a significant predictor for balance point. The researchers also found that balance point was significantly different from baseline and post-measure sessions at all 3 spatial frequencies (P <.01).

The change in balance point occurred in a more negative direction for all 3 spatial frequencies (F_[4,36], 9.27; P <.001) with the effect of deprivation decreasing at 30 minutes compared with earlier evaluations (all P <.02).

The change in BP across the 3 spatial frequencies did not reach significance, but the small sample size may have affected this result.

Significant positive correlations were observed for area under the curve analyses at 0.5 and 4 c/d frequencies (r, 0.715; P =.020), but no correlations were observed between 0.5 and 6 c/d (r, 0.608; P =.062) or 4 and 6. c/d (r, 0.485; P =.156).

“The sensory eye dominance could be significantly shifted in favor of the deprived eye by short-term monocular deprivation at all spatial frequencies measured, and such plasticity was not dependent on test spatial frequency,” according to the researchers. “Therefore, we do confirm the efficiency of short-term monocular deprivation effect at low to high spatial frequencies. This could help to strengthen the empirical foundation for a new therapy in adults with binocular disorders.”

Study limitations include a small sample size and single center design.