Measurement of ocular torsion after macular translocation: disc fovea angle and Maddox rod.

PURPOSE

To compare two methods of measuring ocular torsion (the subjective Maddox rod [MR] test versus the objective disc-fovea angle [DFA] test) after macular translocation surgery.

METHODS

Ocular torsion was measured on consecutive patients after macular translocation at Duke University Eye Center between August 2001 and April 2002. Both MR and DFA measurements of torsion were made at the same clinic visit 4 to 8 weeks after the translocation surgery and again within 3 months after extraocular muscle surgery to decrease torsion. MR and DFA measurements were each performed by a separate examiner who was blinded to the results of the other method.

RESULTS

Thirty-five patients (35 eyes) were included for evaluation. Twenty-nine of these patients had intorsion measured by both MR and DFA after macular translocation but before extraocular muscle surgery (MR mean of 40.3 + 7.2 degrees v DFA mean of 47.0 + 7.9 degrees [P <.001]). The intrapatient reproducibility of the MR test was high (using four readings per session), with a mean coefficient variation of 4.8%. Twenty-five patients had residual torsion measured by both MR and DFA after extraocular muscle surgery (MR mean of 4.2 + 4.7 degrees v DFA of mean 4.8 + 7.0 degrees). There was good correlation between MR and DFA measurements of torsion (r(2) = 0.9).

CONCLUSIONS

DFA measurement correlates well with MR measurement of torsion in patients after full macular translocation. This study verifies the reproducibility of MR to measure large angles of torsion and offers DFA as a simple corroborative test for measuring ocular torsion in patients with poor vision or cooperation.