Refractive change and optical biometry dynamics after 25-gauge vitrectomy in pseudophakic eyes.

Objective: To investigate the refractive change and optical biometry dynamics after 25-gauge vitrectomy without gas tamponade for macular pathology in pseudophakic eyes.

Design: A prospective observational case series.

Participants: Patients with pseudophakic eyes who were scheduled for vitrectomy owing to macular pathology by an experienced surgeon (T.S.) at the Hayashi Eye Hospital between March 2019 and February 2020.

Methods: The primary endpoint was the change in manifest refraction spherical equivalent (MRSE) between baseline (preoperatively) and 3 months postoperatively. The secondary endpoint was the change in optical biometry parameters obtained by swept-source optical coherence tomography-based biometers between baseline and 3 months postoperatively. Optical biometry parameters included corneal curvature and axial length, evaluated by the IOLMaster 700, and intraocular lens position-that is, lens decentration, lens tilt, and aqueous depth (AQD)-evaluated by the CASIA2.

Results: Thirty-four eyes of 34 patients were enrolled. The mean MRSE values at baseline and 3 months postoperatively were -0.70 ± 1.21 diopter (D) and -0.82 ± 1.27 D, respectively, showing a significant myopic shift of -0.12 ± 0.41 D postoperatively (p = 0.043). There was no significant difference between the pre- and postoperative values of the optical biometry parameters, except for the AQD (4.28 ± 0.34 mm vs 4.27 ± 0.34 mm; p = 0.019).

Conclusions: The results suggest that replacing the vitreous by the aqueous during vitrectomy induces an average myopic shift of -0.12 D.