Journal List > J Korean Ophthalmol Soc > v.54(7) > 1009425

Kyung, Young, and Se: Distance Stereoacuity by Frisby Davis Distance Stereotest after Surgery in Intermittent Exotropic Patients

Abstract

Purpose

To compare distance stereoacuity in patients with intermittent exotropia before and after surgery using the Frisby Davis distance stereotest (FD2), and to determine the preoperative factors that affect the postoperative distance stereoacuity.

Methods

A total of 56 patients with intermittent exotropia were examined for the present study. To determine preoperative factors that affect postoperative distance stereoacuity, age, gender, distance control, and presence of fusion were measured. The deviation angle was measured at near and at distance by using a prism cover test. Distance stereoacuity was measured with the FD2 test.

Results

According to the results of the FD2 test, the mean preoperative distance stereoacuity of patients was 64.7 ± 76.1 sec of arc, and improved to 53.6 ± 85.9 sec of arc postoperatively. The distance stereoacuity improved notably from 63.0 to 40.0 sec of arc after the successful surgery. No significant correlation was present between type of surgery, distance control, presence of fusion, and postoperative improvement of distance steroacuity.

Conclusions

Decreased stereoacuity in intermittent exotropic patients improved postoperatively, and the FD2 test was valuable in evaluating the stereoacuity in intermittent exotropic patients pre- and postoperatively.

References

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Table 1.
Changes in Frisby Davis distance stereotest according to the results of surgery
Results No. of subjects Stereoacuity y (sec arc) p-value*
Preoperative Postoperative
Success 42 63.0 ± 69.5 40.0 ± 58.6 0.00
Overcorrection 4 45.0 ± 10.0 245.0 ± 187.9 0.14
Undercorrection§ 10 80.0 ± 113.5 34.0 ± 9.7 0.07
All subjects 56 64.7 ± 76.1 53.6 ± 85.9 0.04

Values are presented as mean ± SD. Sec arc = seconds of arc.

* Statistics by Wilcoxon signed rank test

8ET ≤ Postoperative deviation at far ≤ 8XT

Postoperative deviation at far > 8ET

§ Postoperative deviation at far > 8XT.

Table 2.
Comparative Stereoacuity Values of Frisby Davis distance stereotest by type of surgery
Type of surgery No. of subjects Stereoacuity (sec arc) p-value*
Preoperative Postoperative
R & R 43 69.0 59.5 0.04
BLR 4 65.0 40.0 0.32
R or R 9 44.4 31.1 0.01

Sec arc = seconds of arc; R & R = recession and resection; BLR = bilateral lateral rectus recession; R or R = lateral rectus recession or medial rectus resection.

* Statistics by Wilcoxon signed rank test.

Table 3.
Comparative stereoacuity values of Frisby Davis distance stereotest by office control
Control No. of subjects Stereoacuity (sec arc) p-value*
Preoperative Postoperative
Good 11 50.9 29.1 0.01
Fair 11 23 50.9 44.4 79.1 0.01 0.04
Poor 22 93.0 39.1 0.03

Sec arc = seconds of arc.

* Statistics by Wilcoxon signed rank test.

Table 4.
Comparative stereoacuity values of Frisby Davis distance stereotest by Worth 4 Dot Test
Results No. of subjects Stereoacuity (sec arc) p-value*
Preoperative Postoperative
Fusion 22 44.6 56.6 0.38
Suppression 34 77.8 53.5 0.04

Sec arc = seconds of arc.

* Statistics by Wilcoxon signed rank test.

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