Abstract
Purpose :
Laser-generated corneal flaps offer a minimally invasive option for vision correction compared to mechanical keratome-generated flaps. The short pulse regime of the dual pulse LENSAR ALLY Femtosecond Laser has demonstrated improved corneal cutting capability in cataract surgery. This feasibility study introduces a potential novel modality of corneal flap creation for the LENSAR ALLY Femtosecond Laser System in the short pulse regime.
Methods :
Corneal flap generation was evaluated in both porcine and donor eye tissue. A single corneal flap, 8mm in diameter and centered at the corneal apex, was generated using the short pulse width (350fs) regime. A curved applanation ocular interface was used to constrain the corneal surface to ensure minimal movement, primarily due to the considerable size of the incision. The flap is then generated, using an optimized set of parameters, by the laser cutting a series of spirals at decreasing depths and diameters, forming continuous spirals in the cornea at the pre-programmed corneal depth, followed by a lamellar side cut that forms the flap edge. Flap depth accuracy was assessed using an OCT at intended depths of 100µm and 150µm. Ease of edge opening, flap separation from the underlying stromal bed as well as stromal bed quality, or smoothness, were all assessed under a surgical microscope.
Results :
Following laser treatment, preliminary data showed flap depth was measured to be approximately 110µm ± 23µm and 151µm ± 20µm for intended depths of 100µm and 150µm, respectively. With optimized parameters, the flap edge was easily separated from the surrounding tissue and was generally free of tissue bridges at both depths. Optimized parameters also allowed for easy lifting of the flap from the underlying stromal bed, resulting in a smoother corneal bed. Results indicated consistency across both porcine eyes and donor eye tissue.
Conclusions :
The short pulse width regime of the dual pulse LENSAR ALLY femtosecond laser has previously demonstrated improved effectiveness in corneal treatment. Here, this capability was extended to corneal flap generation, with feasibility tests indicating consistent and accurate corneal flaps that were also easy to open and lift from the underlying stromal bed as well as demonstrated corneal bed smoothness.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.