Step 3: Toric Procedure
Subtle procedural differences distinguish cataract surgery with a monofocal IOL from cataract surgery with a toric lens. These simply include: accounting for cyclorotation using reference marks, marking the steep axis and aligning the IOL once it is implanted.
Watch as Richard Tipperman, MD,* walks through the eye marking process.
*Dr. Tipperman is a paid consultant for Alcon.
Marking the Eye
Marking the eye is the cornerstone for successful toric IOL alignment and is typically performed in two stages: preoperative reference marking and intraoperative marking of the steep axis.
Reference marks account for cyclorotation — the change in the orientation of the eye when a patient moves from a sitting to supine position. Average cyclorotation of the eye is 2–4 degrees; however, some patients will experience up to 15 degrees of cyclorotation. 1 Marking the patient’s eye while they are sitting up will ensure correct orientation of the toric IOL and provide placement guidelines during the procedure.
See an animated demonstration of the reference marking process.
How to create reference marks
Step 1. After dilating drops, have the patient sit upright and align the patient’s head straight forward. Have the patient fixate on an image in the distance.
Step 2. Place marks at 3, 6 and 9 o'clock using a reference marker with ink dotted on its touch points. Or, if marking by hand, mark only at 6 o’clock as it is difficult to mark exactly 180 degrees apart.
Step 3. Prep and drape the patient for surgery.
Reference marking tips
- Make sure numbing drops are dry prior to marking the steep axis.
- Enhance fading marks by marking by hand if necessary.
Axis marks identify the steep axis of astigmatism to ensure optimal alignment. Using the preoperative reference marks you made while the patient was sitting upright, mark the eye at two positions (180 degrees apart) to define the optimal axis to align the toric IOL.
See an animated demonstration of the axis marking process.
How to mark the steep axis
Step 1. Reference the recommended lens placement axis as determined by the toric calculator and corneal topographer.
Step 2. Dial the axis marker to the angle that corresponds with the axis as determined in Step 1, and mark the dialable touch points with ink.
Step 3. Align the stationary touch points of the axis marker with the preoperative reference mark to account for cyclorotation.
Step 4. Place two marks 180 degrees apart on the steep axis of astigmatism.
Axis marking tips
- Avoid excess ink to prevent smearing.
- Check the axis again right before implanting.
- Mark the eye prior to capsulorhexis, incisions and blocks.