Step 2: Surgical Planning for Toric IOL Implantation
The process for selecting the correct toric IOL is twofold:
1) Determine the required spherical lens power by using the preferred method and formula as with conventional IOLs and
2) Determine the magnitude, orientation and type of preexisting corneal astigmatism through keratometry and topography. Once you have captured the patient’s data, the toric calculator will help you determine the surgical plan and select the appropriate lens.
Ophthalmic Consultants of Boston
*Dr. Henderson is a paid consultant for Alcon.
Keratometry is the most important biometric measurement in preparing for a toric IOL procedure. It is used to determine corneal measurements, including corneal curvature and presence and orientation of the steep and flat meridians of astigmatism. Accurate Ks ensure proper IOL selection and toric alignment, resulting in the best possible postoperative outcomes.
- Use the same instrument in pre-op and post-op for each patient
- Take measurements before applying anesthetic or dilating drops
- Repeat your measurements for verification
- Use the same measurement method across your practice
- Designate the same tech to take K measurements
- Make sure Ks are 90 degrees apart
- Patients should stop wearing contact lenses at least two weeks prior to taking measurements
When to remeasure1
- Readings are inconsistent between measurements.
- Corneal power is less than 40.0 D or greater than 47.0 D.
- Average corneal power differs by more than .09 D between eyes.
- Astigmatism for either eye is greater than 2.50 D.
- The corneal diameter (white to white) is less than 10.75 mm or greater than 13.0 mm.