3D analysis of lens geometry before and after cataract surgery

Session Details

Session Title: Monofocal IOLs: New Biomaterials & Visual Performance

Session Date/Time: Tuesday 17/09/2019 | 16:30-18:00

Paper Time: 17:42

Venue: Free Paper Forum: Podium 2

First Author: : P.Hoffmann GERMANY

Co Author(s): :                                 

Abstract Details

Purpose:

Few data is available on the topic of the crystalline lens as well as IOL geometry in relation to the line of sight. Some data was published using purkinjemeters, yet this method has severe limitations dealing with IOLs. Swept Source OCT (ssOCT) allow for enveloping the surface of crystalline as well as artifical lenses and evaluating their 3D-position in relation to the line of sight., including decentration and tilt.

Setting:

Private eye clinic in Germany. Ongoing interventional cohort study.

Methods:

We measured 85 eyes of 85 consecutive cataract patients with the Tomey CASIA2 ssOCT, a machine specifically designed for anterior segment imaging. Measurements were taken one week prior to and 4 weeks after phacoemulsification of femtosecond laser assisted cataract surgery. Two different lens platforms were used: 1. Hoya Vivinex, 2. J&J Tecnis 1piece family. Envelope curves were captured using “semi auto trace” of software version E. Tilt and decentration angles were related to the line connecting the fixation diode light and the fovea (presumed line of sight).

Results:

Mean tilt of the crystalline lens was 5.2° axis 010° in right and 5.6° axis 161° in left eyes. Postoperatively, mean tilt was 5.1° axis 014° and 5.4° axis 162°. Tilt is negatively correlated with axial length. Mean decentration was 0.15 mm x160° in right and 0.18 mm x 182° in left eyes. Postoperatively, we found 0.06 mm x 144° in right and 0.14 mm x 207° in left eyes. Mean change in centration was 0.18 mm from pre- to postoperative visit.

Conclusions:

Tilt and centration were only slightly altered from cataractous to pseudophacic condition. In femtosecond cases, change of tilt and centration was ≈15% smaller compared to manual phaco. 6 month data will be available at the time_of_presentation. Apparent IOL tilt is the result of divergent position of the eye globes while the subject is fixating a distant object with parallel line of sights. Therefore, the line of sight is tilted nasally and slightly upwards in relation to the optical axis of the eye (angle_alpha). In a pseudophacic eye, this will induce aberrations resulting in slight inner astigmatism when refracting the patient.

Financial Disclosure:

None