American Orthoptic Journal Back Content
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Volume 47, 1997, p. 99–102
Stereopsis in Congenital Esotropia
Marshall M. Parks, M.D.
Patients with onset of esotropia at birth or within the first few weeks of age were considered a century ago to be devoid of the potential to develop binocular vision. This notion was refuted in 1939 when Chevasse showed that early surgical alignment of the esotropic eyes was essential for achieving a binocular vision result. Costenbader confirmed this in 1953, followed by Taylor in 1963 and Ing et al. in 1966.
Stereopsis was not found in all congenital esotropes proven to have fusion. The question remained, what percentage of early surgical alignment congenital esotropes have stereopsis? A study of such patients therefore was done and compared against a control study of surgically aligned deteriorated accommodative esotropia patients in order to learn the percentage of each group that manifest stereopsis at an older age when subjective testing for stereopsis is reliable.
Materials and Methods
All surgically aligned congenital and deteriorated accommodative esotropes were selected for study who were examined by me between March 1, 1986 and March 1, 1987. All patients had to have 0-8 of esotropia according to the simultaneous prism and cover test at distance either with their total refractive error corrected by spectacles or with less than total if full strength glasses were not required to maintain the 0-8 of ET. All patients had to have a least a 5 year postoperative follow-up but the findings used in this study were those of their last visit. All patients had to fuse the near Worth 4 lights. The stereopsis testing was conducted with the Titmus Stereo Test which graded the stereo from, 3000 to 40 seconds of arc.
Results
Seventy nine congenital esotropes and 41 deteriorated accommodative esotropia patients were collected. Thirty one of the 79 congenital esotropia patients (39%) had stereopsis. Forty of the 41 deteriorated accommodative esotropia patients (98%) had stereopsis. The average stereo acuity for the congenital esotropia patients was 400 seconds of arc, ranging from 100 to 3000. The average stereo acuity for the deteriorated accommodative esotropia patients was 200 seconds of arc, ranging from 40 to 3000.
Conclusion
Only 39% of aggressively treated congenital esotropic patients who manifested the monofixation syndrome when older had any degree of stereo perception. In contrast 98% of the control group of deteriorated accommodative esotropic patients after surgical alignment had stereo perception. Stereo blindness is presumed to be a genetic feature that occurs within a high percentage of the congenital esotropic patients.
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