What is the preferred deviation in the immediate postoperative period following surgery for infantile esotropia? This is a difficult question to answer, although many have tried. It is clear that the initial deviation may not be stable and may continue to change during the years following surgery. In this issue, Na et al. identified factors associated with re-drift in patients with infantile esotropia. They found a significant difference in the development pattern between esotropic and exotropic drift in that recurrent esotropia occurred predominantly within postoperative year 1, whereas consecutive exotropia continued to appear even 10 years after surgery. All of their patients were followed up for at least 5 years. The presence of a definite fixation preference before surgery and the rate of myopic progression were related to the development of consecutive exotropia, whereas the presence of even a small esotropia on postoperative day 1 was associated with recurrent esotropia.
Na et al. emphasize the importance of delaying surgery until alternate fixation is produced with aggressive occlusion therapy because patients refractory to occlusion treatment showed a high rate of exotropic drift. The authors identified an association between the annual rate of myopic progression and the development of consecutive exotropia that deserves consideration. Because the prevalence of myopia has been increasing in Asian countries, including Korea, they postulate a possible ethnic-specific association that may not have been found in Western studies. Because consecutive exotropia developed at an average of 6.5 years postoperatively, the authors theorize that a myopic shift during postoperative year 5 may be a “risk factor” for exotropic drift.
Of particular importance, the study by Na et al. reported re-drift after surgery in more than 70% of patients with infantile esotropia during a long-term observation period. This finding concurs with the observations of many of my colleagues, who observed their patients for many years. Confirmation of these findings requires detailed measurements of strabismus both before and after surgery and close observation of postoperative deviations and changes in refractive status over time in patients.
Rudolph S. Wagner, MD