Measuring normal ocular torsion and its variation by fundus photography in children between 5-15 years of age.

Cycloposition has been measured by various methods; however, fundus photography is the most reliable method to evaluate the torsion objectively. We did a prospective study to find out the disc foveal angle (DFA) and its variation in children without squint. We included 210 eyes of 105 children between the ages of 5-15 years. DFA was calculated using standard technique after taking a fundus photograph. The cycloplegic refraction was done and compared. The mean age was 10.6 +/- 2.5 years. Mean DFA in right eye (RE) was 6.49 +/- 3.25 degrees (0-13 degrees ) and in left eye (LE) was 5.80 +/- 3.29 degrees (0-12 degrees ). The difference between the RE and LE was statistically not significant (P=0.131) (mean 1.15 +/-1.39 degrees ). Mean DFA in emmetropic children was 6.1 degrees +/- 3.4 degrees (n=112 eyes). DFA varies widely in children. The difference observed in DFA measurement for eyes with various refractive errors were compared with DFA measurements for emmetropic eyes.