Investigating the correlation between scleral spur angle and intraocular lens tilt

To evaluate the correlation between the preoperative vertex-scleral spur angle (Vtx-SSA) and postoperative horizontal intraocular lens (IOL) tilt after routine cataract surgery.

Cullen Eye Institute, Baylor College of Medicine, Houston, Texas.

Prospective case series.

This study enrolled patients who underwent uneventful phacoemulsification cataract extraction with IOL implantation. The Anterion and Eyestar 900 swept-source optical coherence tomographers (SS-OCTs) were used to determine Vtx-SSA and lens tilt (crystalline and IOL) measurements, respectively. Tilt vectors were decomposed into orthogonal, vertical, and horizontal components to explore preoperative correlations independently. The Pearson correlation coefficient and linear regression analysis were used to evaluate the relationships between select variables.

In a cohort of 72 eyes of 72 patients, the preoperative Vtx-SSA was highly correlated with horizontal IOL tilt ( r2 = 0.97, P < .01). On average, tilting of the IOL in the horizontal axis accounted for nearly 80% of the total tilt magnitude. Crystalline lens measurements revealed a similarly strong correlation between horizontal tilts of the crystalline lens and IOL ( r2 = 0.97, P < .01). However, IOL tilt along the vertical meridian may be more difficult to anticipate using crystalline lens measurements ( r2 = 0.78, P < .01) and showed no correlation with axial length ( r2 = 0.00, P = .92).

The Vtx-SSA may be used as an easy-to-interpret presurgical surrogate for estimating horizontal IOL tilt. Still, it does not account for more minor contributions of tilt in the vertical plane.