Published in:
01-03-2014 | Clinical Investigation
Prevalence and anatomic mechanism of highly myopic strabismus among Japanese with severe myopia
Published in: Japanese Journal of Ophthalmology | Issue 2/2014
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Purpose
To survey the prevalence of highly myopic strabismus among patients with severe myopia and to elucidate its anatomic mechanism.
Methods
The subjects (mean age 48.5 ± 17.8 years) were 452 Japanese patients (778 eyes) who presented between May 2011 and April 2012 and were diagnosed as severely myopic (objective refractive error ≥−6.00 D or axial length ≥27 mm). For diagnosis, the eye position at 0.33 m, axial length, and diagnostic positions of gaze were determined; magnetic resonance imaging (MRI) was also used.
Results
Sixteen eyes of 9 patients fulfilled the disease criteria, and strabismus fixus was observed for 3 eyes of 3 patients. Disease prevalence was 2.65 %. The mean age of the 12 patients was 65.5 ± 17.9 years. For 18 eyes for which the axial length could be measured, mean axial length was 28.9 ± 2.03 mm. For the 16 eyes examined by MRI the mean dislocation angle was 132° ± 14.0°. The axial length was 26 to <30 mm for 13 of the 16 eyes, dislocation angle was 110° to <150° for 14 eyes, and both axial length and dislocation angle were within these ranges for 12 eyes.
Conclusions
The prevalence of the disease was 2.65 %. However, this was not a general epidemiological survey and the screening criteria did not adequately cover all disease cases. In addition, even for eyes that are still mildly–moderately myopic, this disease can develop in the presence of orbital pulley abnormalities.