Abstract
Purpose :
Corneal flaps generated by femtosecond lasers offer a minimally invasive option for vision correction compared to those created using a mechanical keratome. Additionally, femtosecond lasers offer flap design customization as well as demonstrate increased safety, efficacy and efficiency compared to manual flap creation. This study investigates the benefits of the novel pre-treatment laser marking (LM) technique by assessing the accuracy of flap thickness in a porcine eye model across 3 LENSAR ALLY® femtosecond laser systems.
Methods :
Flap thickness accuracy was first evaluated with and without LMs at a single incision depth in ex-vivo porcine eyes on an ALLY system followed by evaluating flap thickness with LMs on 2 other ALLY® systems. Immediately prior to the flap incision, a 9mm diameter flap centered at the corneal apex, nine small intrastromal marks are cut to ensure proper flap placement. Once marks are made and measured, a flap is then created using an optimized set of parameters. Following treatment, incision depth accuracy was assessed using an OCT at intended flap thicknesses of 100µm and 150µm. Six eyes per depth were lased on each system, ALLY®1, ALLY®2 and ALLY®3. Two OCT images were acquired, one along the horizontal plane and one along the vertical plane, and three measurements per image were obtained, one at the apex and two at the peripheries, on either side of the apex.
Results :
On ALLY®1, flaps cut with LMs at a 150µm intended depth measured 145µm ± 3µm and 151µm ± 5µm at the apex and peripheries, respectively, vs 143µm ± 15µm and 149µm ± 10µm without LMs. With the LMs on and the flap cut at an intended depth of 100µm on ALLY®1, flap thickness was measured to be 99µm ± 4µm and 101µm ± 4µm at the corneal apex and the peripheries, respectively. ALLY®2 at 100µm demonstrated incision depths of 119µm ± 5µm at the apex and 120µm ± 4µm at the peripheries and at 150µm, depths measured 170µm ± 3µm and 169µm ± 5µm at the apex and peripheries, respectively. Flap thickness on ALLY®3 was measured as 96µm ± 5µm at the apex and 99µm ± 5µm at the peripheries and 147µm ± 5µm at the apex and 152µm ± 5µm at the peripheries for intended depths of 100µm and 150µm, respectively.
Conclusions :
This innovative pre-treatment laser marking technique is effective for the ALLY® system to generate accurate, consistent and uniform flaps in patients undergoing LASIK surgery.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.