PT  - JOURNAL ARTICLE
AU  - J Cooper
AU  - K J Ciuffreda
AU  - P B Kruger
TI  - Stimulus and response AC/A ratios in intermittent exotropia of the divergence-excess type.
AID  - 10.1136/bjo.66.6.398
DP  - 1982 Jun 01
TA  - British Journal of Ophthalmology
PG  - 398--404
VI  - 66
IP  - 6
4099  - http://bjo.bmj.com/content/66/6/398.short
4100  - http://bjo.bmj.com/content/66/6/398.full
SO  - Br J Ophthalmol1982 Jun 01; 66
AB  - Objective infrared recording devices were used to measure simultaneously and continuously both accommodation and accommodative vergence to near stimuli in 4 subjects with intermittent exotropia of the divergence-excess type (2 simulated and 2 true). In addition standard clinically determined stimulus accommodative convergence to accommodation (AC/A) ratios were measured. Results showed the mean group response AC/C ratio to be 5.9/1 (range 4.5-8.0/1) with no differences between true and simulated divergence-excess. Similar AC/A ratios were found after 45 minutes of monocular occlusion. Our results clearly demonstrate relatively normal response AC/A ratios in these subjects. Thus, contrary to what is believed by many clinicians, the reduced ocular deviation at near compared with distance vision cannot be attributed primarily to an abnormally high AC/A ratio. We believe than fusional convergence after-effects and/or proximal convergence effects contribute to inflate the clinically determined stimulus AC/A ratios.