This article is more than 5 years old. Information may no longer be current.
Laser-assisted crescent resections reshape ectatic corneas
A new procedure that reshapes ectatic corneas with laser-assisted crescent resections achieves refractive correction, reduces irregular astigmatism and higher-order aberrations, and decreases anterior chamber depth without narrowing the optical zone or weakening the cornea.
The ablation patterns are created by processing and integrating the topography and pachymetry data of the CSO Sirius into the Schwind Amaris 1050 excimer laser, using the PALK-CAM software, according to the study. A special mask is applied to block the laser beams targeted outside the desired ablation profile and to generate smooth crescent-shaped perforations with continuous curvilinear margins at a depth of 90%.
The diameter of the perforations is 8 mm at the center, gradually tapering toward both ends. The length and width of resection varies according to the degree of keratoconus. The edges of the removed areas are then closed using 10-0 interrupted nylon sutures.
Three cases with keratoconus graded 2 to 3 were operated on with this method. Root-mean-square higher-order aberration and coma were effectively reduced, and the spherical equivalent decreased significantly. Anterior chamber depth, which is greater in eyes with keratoconus and tends to widen with the progression of the disease, was also effectively reduced.
Authors César Carriazo, MD, and María José Cosentino, MD, told Primary Care Optometry News: “By performing corneal remodeling it is possible to reshape a cornea with keratoconus by correcting the irregular astigmatism and looking for the patient's emmetropia at the same time. The corneal stroma in keratoconus is thin and redistributed. For this reason, by calculating and removing this redistributed stromal volume, we can come back to normal corneas.”
They wrote in the study: “Although the initial outcomes are promising, there is a need to standardize the nomogram.”
They are currently working on this nomogram and will publish their results in the near future. – by Michela Cimberle
Disclosure: The authors reported no conflict of interest