Investigating a possible cause of the myopic shift after combined cataract extraction, intraocular lens implantation, and vitrectomy for treatment of a macular hole

Abstract

Objective: It has been documented that combination surgery (phacoemulsification, intraocular lens implantation, and vitrectomy) produces a postoperative myopic shift. We hypothesize that the myopic shift seen in patients treated with combination surgery, membrane stripping, and injection of C 3F 8 for treatment of a macular hole is due to an erroneously short preoperative axial length measurement by the IOLMaster. Study Design: Retrospective chart review. Participants: Eleven eyes of 10 patients treated for a stage III or IV macular hole were recruited from a database search of 1 vitreoretinal practice in Regina, Sask. Methods: All eyes included in the study underwent combination surgery, membrane stripping, and injection of C 3F 8. None of the patients demonstrated concurrent eye pathology. Postoperative axial length measurements by the IOLMaster were obtained and compared with the same preoperative measurements. Results: The mean (SD) postoperative myopic shift seen in the study eyes was −0.76 (0.65) D ( z = −2.578, p < 0.01 ).The mean (SD) preoperative and postoperative axial length measurements were 23.54 (1.02) mm and 23.53 (1.01) mm, respectively. No significant difference in axial length was found between the preoperative and postoperative axial length measurements ( t = 0.43, df = 10, p = 0.68). Conclusions: These findings do not support our hypothesis of an erroneous preoperative axial length measurement by the IOLMaster in patients with a stage III or IV macular hole treated with combination surgery, membrane stripping, and injection of C 3F 8. Further studies are required to determine the precise cause of the postoperative myopic shift.