Sine Amsler Charts: a new method for the follow-up of metamorphopsia in patients undergoing macular pucker surgery

Purpose: To evaluate our new method for the follow-up of metamorphopsia in patients with a macular pucker. Methods: Sine Amsler Charts (SAC) are a set of eight modified Amsler charts where we have replaced the straight lines by sine curves of the same frequency but with different amplitudes (grades I-VIII). The patient first examines a regular Amsler chart with the affected eye; subsequently the SAC are presented in random order to the fellow eye. With this eye the patient then selects the SAC with the amplitude that,best corresponds to the metamorphopsia observed with the affected eye. After 30 min the test was repeated. A comparison of pre- and postoperative SAC scores was made in 63 patients. The correlations between preoperative visual acuity, membrane type, leakage on fluorescein angiography, preoperative SAC score, postoperative SAC score and postoperative visual acuity were analyzed. Results: Preoperative repeat testing with the SAC revealed 100% reproducibility in the grading of metamorphopsia. Postoperative SAC was unchanged in 16% of cases, one grade lower in 54%; two grades lower in 21% and more than two grades lower in 7%. Postoperative visual acuity was unchanged (i.e., within two EDTRS lines of the preoperative value) in 49% of cases; improved in 48% and decreased in 3%. A decrease in SAC score with a two-line increase in visual acuity occurred in 43% of cases. Conclusion: The SAC examination is a reproducible and rapid method for the comparison of the preoperative and postoperative metamorphopsia in patients undergoing pucker surgery and it may serve as an additional outcome measure.