J Korean Ophthalmol Soc.  2009 Sep;50(9):1371-1376. 10.3341/jkos.2009.50.9.1371.

The Meaning of Monocular Occlusion on Preoperative Evaluation in Basic Intermittent Exotropia

• Jang SY
• Lee JY
• Park SH
• Kim SY

• KMID: 2212621
• DOI: http://doi.org/10.3341/jkos.2009.50.9.1371

Abstract

PURPOSE
To assess the clinical potential of one-hour monocular occlusion on preoperative alignment evaluation in basic intermittent exotropia. METHODS: Twenty-nine patients with basic intermittent exotropia who were preoperatively examined for one-hour monocular occlusion were selected (monocular occlusion group). Their records were reviewed retrospectively. The measured angle after one hour of monocular occlusion was used to determine the surgical target angle. The control group consisted of 29 patients whose age, sex and control state were similar to the monocular occlusion group. Measurement of the angle of strabismus was not done in the control group. Surgery was performed for the measured angle at six meters. The results of surgery were used to compare the groups relative to the control state. RESULTS: Fifteen patients (51.7%) had an increase in the distance deviation after one hour of monocular occlusion. Of the patients with good control, 78.6% (11/14) had an increase in the angle of misalignment. Only 26.7% (4/15) of patients with poor control experienced a change in the angle deviation (p<0.05). In all, 79.3% of patients in the study group and 75.9% of those in the control group had a satisfactory surgical outcome. Among the patients with good control, 85.7% of patients who underwent surgery for increased angle had a satisfactory outcome, compared with 71.4% of patients who underwent surgery for initial angle (p=0.375). CONCLUSIONS: One-hour monocular occlusion might help to prevent undercorrection after surgical treatment by identifying the hidden deviation, especially in the patients whose control over the distance deviation was good.

Keyword

Basic type; Fusion; Intermittent exotropia; Monocular occlusion

MeSH Terms

Exotropia
Humans
Retrospective Studies
Strabismus

Reference

References

1. Von Noorden GK. Binocular Vision and Ocular Motility. Therapy and Management of Strabismus. 5th ed.St Louis: CV Mosby;1996. p. 343.

2. Rah SH, Jun HS, Kim SH. An epidemiologic survey of strabismus among school-children in Korea. J Korean Ophthalmol Soc. 1997; 38:2195–9.

3. Hardesty HH, Boynton JR, Keenan JP. Treatment of intermittent exotropia. Arch Ophthalmol. 1978; 96:268–74.

4. Parks MM. Ocular Motility and Strabismus. Hagerstown, Md: Harper & Row;1975. p. 113–22.

5. Burian HM, Spivey BE. The surgical management of exodeviations. Am J Ophthalmol. 1965; 59:603–20.

6. Ohtsuki H, Hasebe S, Kono R, et al. Prism adaptation response is useful for predicting surgical outcome in selected types of intermittent exotropia. Am J Ophthalmol. 2001; 131:117–22.

7. Arnoldi KA, Reynolds JD. Assessment of amplitude and control of the distance deviation in intermittent exotropia. J Pediatr Ophthalmol Strabismus. 2008; 45:150–3.

8. Parks MM, Mirchell P. Clinical Ophthalmology. I. Philadelphia: JB Lippincott;1988. p. 1.

9. Kushner BJ. The distance angle to target in surgery for intermittent exotropia. Arch Ophthalmol. 1998; 116:189–94.

10. Kushner BJ. Exotropic deviations: A functional classification and approach to treatment. Am Orthopt J. 1988; 38:81–93.

11. Cooper J, Medow N. Major review: intermittent exotropia basic and divergence excess type. Binoc Vis Eye Muscle Surg Q. 1993; 8:185–216.

12. Von Noorden GK. Binocular Vision and Ocular Motility. Therapy and Management of Strabismus. 5th ed.St Louis: CV Mosby;1996. p. 85–100.

13. Kushner BJ. Selective surgery for intermittent exotropia based on distance/near differences. Arch Ophthalmol. 1998; 116:324–8.

14. Kushner BJ, Morton GV. Distance/near differences in intermittent exotropia. Arch Ophthalmol. 1998; 116:478–86.

15. Kono R, Hasebe S, Ohtsuki H, et al. Characteristics and variability of vertical phoria adaptation in normal adults. Jpn J Ophthalmol. 1998; 42:363–7.

16. Marlowe FW. Prolonged occlusion as a test for muscle balance. Am J Ophthalmol. 1921; 4:238–50.

17. Kushner BJ, Morton GV. Diagnostic occlusion in strabismus management. J Ocul Ther Surg. 1983; 2:194–200.

18. Scobee RG. The oculorotatory Muscles. St Louis: CV Mosby;1952. p. 172.

19. Burian HM, Franceschetti AT. Evaluation of diagnostic methods for the classification of exodeviations. Trans Am Ophthalmol Soc. 1970; 68:56–7.

20. Niederker O, Scott WE. The value of diagnostic occlusion for intermittent exotropia. Am Orthop J. 1975; 25:90–1.

21. Cooper EL. Purposeful overcorrection in exotropia. Kanger S, Giessen , editors. International strabismus symposium;1966. p. 311–8.

22. Scott WE, Keech R, Mash AJ. The postoperative results and stability of exodeviations. Arch Ophthalmol. 1981; 99:1814–8.

23. Kim SH, Kim SY, Kwon JY. Change of deviation angle after monocular occlusion in intermittent exotropia. J Korean Ophthalmol Soc. 2005; 46:1175–82.