Extreme Regular Astigmatism: Bilateral Sequential Cataract Surgery With Zeiss At Torbi 719M Using Total Keratometry–Based Planning And Callisto Digital Alignment

To present bilateral cataract surgery in a patient with extreme regular corneal astigmatism treated with very high-cylinder toric IOLs (ZEISS AT TORBI 719M, up to +11.00 D), emphasizing Total Keratometry (TK)–based planning with the ZEISS toric calculator and precise intraoperative axis alignment using CALLISTO eye digital guidance.

Tertiary eye clinic. Sequential phacoemulsification with in-the-bag implantation of high-power toric IOLs, planned with ZEISS Toric Calculator using Total Keratometry and aligned with CALLISTO eye.

A 64-year-old female with bilateral cataract and extreme regular astigmatism underwent sequential phacoemulsification. Corneal tomography confirmed a regular pattern. Total Keratometry measurements used for toric planning showed OD astigmatism 8.38 D (TK1 40.79 D @12°, TK2 49.17 D @102°) and OS astigmatism 6.92 D (TK1 41.11 D @158°, TK2 48.03 D @68°). Axial length was 22.96 mm (OD) and 23.05 mm (OS). IOL power and axis were calculated with the ZEISS Toric Calculator incorporating SIA 0.12 D @180°. Surgery was uneventful. A ZEISS AT TORBI 719M +20.50 D with cylinder +11.00 D was implanted in OD and aligned at 102° (13/05/2025). In OS, a ZEISS AT TORBI 719M +20.50 D with cylinder +9.00 D was implanted and aligned at 69° (26/02/2026). Axis positioning was performed with CALLISTO eye digital guidance. Postoperatively, both toric IOLs remained well centred and stable. Final refraction was OD −0.75 D (axis 5°) and OS +0.50/−1.00×135°. Despite residual refractive error, the patient achieved uncorrected distance visual acuity of 1.0 (decimal) with stable pseudophakia in both eyes.

This case illustrates that even extreme regular astigmatism (≈7–8 D) can be substantially reduced with very high-cylinder toric IOLs when planning is TK-based and alignment is tightly controlled. Use of ZEISS Total Keratometry within the toric calculator and CALLISTO-guided digital axis alignment enabled implantation of an AT TORBI 719M toric range up to +11.00 D with stable centration and excellent uncorrected vision, supporting feasibility and predictability of toric correction in extreme cases.