J Korean Ophthalmol Soc.  2012 Nov;53(11):1663-1668.

Myopic Progression and Postoperative Exodrift in Patients with Intermittent Exotropia

• Kim MH
• Chung SA
• Choi AY
• Lee JB

Abstract

PURPOSE
To investigate the relationship between myopic progression and exodrift after surgery in patients with intermittent exotropia (X[T]).
METHODS
Eighty-five patients who underwent bilateral lateral rectus recession for X(T) and had a follow-up of more than 1 year were recruited for the present study. Progression of myopia was determined by measuring the difference in spherical equivalent of both eyes between the initial and final refraction divided by the total follow-up time per patient. Postoperative exodrift was calculated by subtracting the deviation at postoperative 6 weeks from the deviation at the last follow-up, and the deviation at postoperative day 1 from the deviation at postoperative 6 weeks. Linear regression was conducted to determine the relationship between postoperative exodrift and myopic progression. The risk factors for recurrence, defined as exodeviation of 10 prism diopters or more at the final examination, were also analyzed.
RESULTS
Sixty-eight (80.0%) subjects showed myopic progression of -0.50 diopters or more, and 47 (55.3%) had recurrence of exotropia during the mean follow-up period of 37.9 months. Patients with myopic progression showed more exotropic drift after postoperative 6 weeks than the patients without myopic progression (p < 0.01). Immediate postoperative overcorrection, oblique dysfunction, and a short follow-up period were associated with a low recurrence, whereas preoperative angle of exodeviation, sensory status, and age at the time of surgery were not.
CONCLUSIONS
In patients who underwent bilateral lateral rectus recession for X(T), a greater myopic progression was related with greater postoperative exodrift. As the development of myopia was observed to be axial in nature, the results from the present study raises the possibility that ocular elongation may reduce the effect of recession.

Keyword

Bilateral lateral rectus muscle recession; Exodrift; Intermittent exotropia; Myopic progression; Ocular elongation

MeSH Terms

Exotropia
Eye
Follow-Up Studies
Humans
Linear Models
Myopia
Recurrence
Risk Factors

Figure

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  Figure 1 Correlation between late exodrift (EOMfinal - EOM6weeks) and myopic progression. (A) Late exodrift at far = 5.775 - 1.237 × Myopic progression (p=0.034, linear regression). (B) Late exodrift at near = 5.243 - 2.949 × Myopic progression (p = 0.001, linear regression). PD = prism diopters; D = diopters.

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  Figure 2 Schematic explanation of correlation between myopic progression and postoperative exodrift. As the progression of myopia is axial in nature, these results raise the possibility that ocular elongation may reduce the effect of recession.

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