This study aims to assess the accuracy of toric intraocular lens (IOL) alignment axes as calculated and displayed by a novel digital guidance system. In addition, it evaluates the time required to initiate surgical guidance and postoperative refractive astigmatism following toric IOL implantation.

This single-surgeon, single-site, prospective, non-invasive observational study evaluated the accuracy of toric IOL alignment axes calculated and displayed by the digital guidance system (Cassini Technologies, B.V.) in 100 eyes. The intraoperatively calculated alignment axes were compared to preoperative measurements to assess their accuracy (in degrees). Postoperative outcomes, including residual refractive astigmatism (diopters) and visual acuity (Snellen), were recorded at 1 month postoperatively.

Inclusion criteria:

• Patients undergoing uncomplicated cataract surgery with toric IOL implantation,
• Eyes implanted with a toric IOL.

Exclusion criteria:

• Ocular comorbidity likely to impair postoperative visual acuities, or
• History of ocular trauma or zonular instability, or
• Previous refractive surgery, or
• Irregular corneal astigmatism or keratoconus, or
• Patients with physical or intellectual disabilities that may prevent reliable fixation or comprehension (e.g. Down's Syndrome, Parkinson's Disease), or
• Patients with unreliable biometry measurements, or
• Severe dry eye disease or ocular surface disease.