Use of Small Femtosecond Laser-Created Intrastromal Corneal Marks as Visual Aid in Rotational Orientation of Toric IOLs
Narrative Responses:
Purpose
Surgeons’ dependence on ink marks placed manually on the limbus to orient the axis of toric IOLs in the capsular bag is inherently inaccurate partly because of parallax error which occurs in final alignment. We evaluated whether small femtosecond laser-created marks within the corneal stromal could improve toric IOL alignment.
Methods
Patients (n=50) undergoing toric IOL cataract surgery had the 3 and 9 o’clock position pre marked on the limbus. Then the surgical eye was coupled to the Catalys (AMO) femtosecond cataract laser and the laser was custom oriented to the limbal marks. Then paired marks, 10 degrees in arc length, were lased within the corneal stroma at an optic zone (OZ) of 8.0mm along the intended axis of toric IOL placement. The toric IOL was oriented parallel to the laser marks and final orientation was confirmed with intraoperative aberrometry. Intended versus achieved IOL orientation was evaluated at one month postoperatively.
Results
At one month postop, the toric IOL axis was within ± 5 degrees of the intended axis as examined at a slit lamp in all 50 eyes studied. Residual refractive cylinder averaged 0.37 diopters (D), (range 0.00 D – 1.00 D) with the anticipated residual refractive cylinder being 0.33 D. There was very close correlation between the corneal marks and the toric IOL axis on the first postoperative day (all ± 2 degrees). The intrastromal axis marks were invisible in all cases by one month. No intraoperative or postoperative complications occurred as the result of the laser marking.
Conclusion
The use of fs laser-created marks within the corneal stroma as an aide in the rotational orientation of toric IOLs is an accurate and complication-free technique to achieve close to the intended final alignment of toric IOLs.