Accuracy Of Toric Intraocular Lens Axis Marking Preoperatively Using Slit Lamp Method

Toric intraocular lenses are used to correct preop astigmatism. Accurate marking of the axis of IOL placement is important. There are various methods available to mark the toric axis. Simplest being bubble marker, slit lamp to advance technologies like Varion.

Retrospective analysis of patients who had toric IOL implanted during the period September 2024 to December 2025 operated by the presenting author, Coauthor .

We collected the data of the patients who had toric IOL implanted during the period-2024 to 2025. In all the patient's toric axis was marked by making the patient sit in front of slitlamp. With the slit beam in horizontal orientation, 0–180-degree axis was marked. Then the slit beam was rotated to 90 degrees, and 90-degree axis was marked. A Mobile app, was used to measure the accuracy of toric marking, and the desired axis of the toric IOL was recalculated depending on the rotation of the camera. All patients undrwent standard phacoemulsification with temporal clear corneal incision. Toric IOL was positioned along the axis which was marked using the slit lamp before the surgery.

A total of 41 patients were included in the study. Preop astigmatism varied from 0.75to 2.5 D.Against-the-rule astigmatism was the most common type, seen in 20 eyes (48.8%), followed by with-the-rule astigmatism in 14 eyes (34.1%) and oblique astigmatism in 7 eyes (17.1%). Monofocal intraocular lenses were implanted in 19 eyes (46.3%), while EDOF and multifocal intraocular lenses were each implanted in 11 eyes (26.8%). 4 patients had capsular tension ring inserted, 2 patients underwent Kahook dual blade goniotomy as additional procedures.Post op residual astigmatism was negligible. All the pts had post op visual acuity of 6/6 at 6 weeks postop. No patient needed repeat intervention to re-position the IOL.

Slit lamp is a useful and less expensive tool to mark the axis of toric IOL preoperatively.