Skip to main content
. Author manuscript; available in PMC: 2014 Aug 18.
Published in final edited form as: JAMA Ophthalmol. 2013 Nov;131(11):1413–1419. doi: 10.1001/jamaophthalmol.2013.4484

Table 3.

Percentage of Participants With Binocular Summation and Binocular Inhibitiona,b

% of Participants
With Binocular
Summation
(BiS >1.1)		 With Binocular
Inhibition
(BiS <0.9)
ETDRS letters
  Strabismic participants 7 5
  Control participants 10 0
  P value .80 .10
2.5% Sloan letters
  Strabismic participants 25 16
  Control participants 75 0
  P value <.001 <.001
1.25% Sloan letters
  Strabismic participants 21 44
  Control participants 64 11
  P value <.001 <.001
Pelli-Robson CS
  Strabismic participants 9 3
  Control participants 0 12
  P value .10 .10
Sweep VEP CS
  Strabismic participants 32 49
  Control participants 36 46
  P value .70 .90

Abbreviations: BiS, binocular summation score; CS, contrast sensitivity; ETDRS, Early Treatment Diabetic Retinopathy Study; VEP, visual evoked potential.

a

Binocular summation score calculated as a ratio between the binocular letter score and the better-eye letter score for the ETDRS and 2.5% and 1.25% Sloan letter charts. For the Pelli-Robson CS and sweep VEP CS tests, the BiS was calculated as a ratio between the better-eye CS score and the binocular CS score.

b

P values calculated by 2-tailed Fisher exact test.