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Designing new instruments
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As our surgical techniques continue to evolve, we often notice that our trusted surgical instruments may not be the ones best suited for the job. Sometimes the best tool for the job is the one that has not yet been designed. In cataract surgery, the recent popularity of toric IOLs has inspired surgeons to devise their own instruments for marking and positioning these lenses with a high degree of accuracy.
We've learned that marking an eye while the patient is supine can be less than accurate due to cyclotorsion of the eye. And with a toric IOL, being misaligned by just 10° will cause one-third of the astigmatic correction to be lost. Clearly, accuracy counts.
 Devgan corneal axis marker. |
Byron Stratas, MD, of Tarpon Springs, Fla., taught me to use anterior corneal stromal puncture to mark the axis for a toric IOL. Then, using the red reflex of the operating microscope, the axis dots of the toric IOL can be aligned with the dots of the anterior corneal stromal puncture. To further enhance this technique, I worked with Accutome to design a toric axis marker that inserts into the applanation holder of the slit-lamp microscope (I have no financial interest and no royalties in this product). There are curved marking tips to match the contour of the cornea, and they are spaced 6 mm apart to provide ideally spaced marks for toric IOL alignment. The center is hollow to allow centration over the pupil prior to marking. The metal markers leave an imprint on the cornea for up to 24 hours, but using the technique of 30-gauge anterior corneal stromal puncture, marks can be seen for up to 2 weeks.
I have found that this has helped to improve accuracy with toric IOL placement, which results in patients with better visual outcomes. And that's the purpose of any new instrument design.