Virtual Reality Assessment Reveals Myopic Regression After ICL Implantation in High Myopia

To investigate the correlative factors of vision regression after Implantable Collamer Lens (ICL) surgery from the perspective of binocular vision and to develop a predictive model for the refractive change over the long term.

This was a prospective study of 30 subjects (60 implants), who underwent ICL surgery at Guangdong General Hospital. Corrected distance visual acuity, uncorrected distance visual acuity, spherical equivalent (SE), axial length and binocular examination using virtual reality were analyzed before, 1 month and 1 year after the surgery.

Mean SE was (-12.01 ± 0.86) D preoperatively, (-0.44 ± 0.13)D 1 month postoperatively and (-0.97 ± 0.15)D 1 year postoperatively. The average regression 1 year postoperatively (-0.53 ± 0.25D of SE) was significant (P = 0.01). Mean axial length at the base line and 1 year after the surgery was (28.35 ± 0.39) mm and (28.91 ± 0.57) mm. The regression was correlated with the binocular equilibrium difference (r = 0.553, P = 0.002), and the degree of perceptual eye position shift, especially the horizontal shift (r = -0.620, P = 0.000). The important variables relevant to myopic regression were preoperative horizontal perceptual eye position shift (B = -0.007, P = 0.001) and binocular equilibrium difference (B = 0.146, P = 0.012).

Perceptual eye position deviation and the binocular equilibrium difference could cause binocular gazing instability, and the unstable retinal image created a 'micro retinal-defocus phenomena', leading to an elongation of the axial length and resulting in myopic regression after ICL surgery.