Rotational Stability After Nanoflex Collamer Toric Intraocular Lens Implantation in Astigmatic Patients Undergoing Cataract Surgery

A good rotational stability of toric intraocular lenses (T-IOL) allows an accurate refractive correction. However, many aspects -both pre-operative and post-operative- can interfere causing T-IOL rotation and misalignment.

Complete preoperative ocular evaluation is performed including slit-lamp examination, uncorrected distance visual acuity (UDVA), best-corrected visual acuity (BCVA), Javal keratometry, corneal Scheimplug tomography (Pentacam), optical biometry (IOL Master), Goldman applanation tonometry and fundus evaluation through dilated pupils. The spherical IOL power is calculated considering the axial length obtained with optical biometry, the magnitude of astigmatism derived from Javal keratometry and the steepest axis obtained with corneal tomography. The power of the toric IOL is determined with the online Staar Toric IOL calculator. The reference landmarks are also marked preoperatively with a sterile methylene blue fine point pen. The marking is rechecked in the operating theatre with the electronic toric marker ASICO.

Postoperative evaluation for IOL alignment and rotational stability is performed with slit-lamp photography on dilated pupils. Images are captured with Haag Streit slit lamp BQ 900 and are evaluated with the image-analysis software Protractor (Staar).