China
Africa
Explore chapters and articles related to this topic
Laser refractive surgery
Published in Pablo Artal, Handbook of Visual Optics, 2017
Jorge L. Alió, Mohamed El Bahrawy
Barraquer’s law of thicknesses in 1964 described the corneal flatness with central tissue removal and steepness with peripheral tissue removal.11 He then made trials of some other techniques to improve his methods as the keratophakia, which involves suturing a donor stromal disc under the initial cap, and then came the trials of Kaufman and Werblin in 1979, describing epikeratophakia, both aiming at overcoming the need to use the cryolathe, but the described techniques were reported to be neither predictable nor safe. Students of Barraquer raised the keratomileusis to its highest state of precision; the first was Swinger with the help of Krumeich, when they described the Barraquer–Krumeich–Swinger nonfreeze technique (Figure 15.3), a method of changing the shape of the cornea without freezing it, using a dye then a second pass of the microkeratome, with the aim of reducing surgical trauma and visual recovery time. The second was Luis Ruiz, who modified the principles of microkeratome by using an automated form called the automated lamellar keratoplasty (ALK), to correct high levels of myopia and hyperopia while avoiding irregular sections through a constant and reproducible speed of this automated microkeratome. It was Ruiz also who came up with the idea of passing the microkeratome a second time with the patient on table but with different suction setting, a procedure to be called in situ keratomileusis, and later demonstrated that by stopping the microkeratome before the end of the pass, it is possible to create a flap with a hinge that can be replaced again with no need for the previously required suture of the disc securing it with overnight patching.12
Effects of Superficial Keratectomy in Peripheral Hypertrophic Subepithelial Corneal Opacification on Front and Back Corneal Astigmatism
Published in Current Eye Research, 2021
Jana C Riedl, Alexander K Schuster, Aytan Musayeva, Joanna Wasielica-Poslednik, Susanne Marx-Gross, Adrian Gericke
Several previous studies compared the outcomes of superficial keratectomy, phototherapeutic keratectomy and automated lamellar keratoplasty in Salzmann’s nodular degeneration.7–9 However, the studies all focused on the safety and efficacy of the surgical interventions. They all reported an increase in visual acuity and a stable outcome in the follow up period. Analysis of the corneal astigmatism has not been performed before. It is still a matter of debate whether Salzmann’s nodular degeneration belongs to the same clinical entity as PHSCO. There are some main differences regarding both pathologies. In the present study, none of the eyes had a history of ocular inflammation or trauma, while Salzmann’s nodular degeneration was reported to present after ocular infections. So far, there are just small and limited studies evaluating the clinical outcomes of surgeries for PHSCO and some authors regard both diseases as one entity, which is why also data for Salzmann’s nodular degeneration are often taken into account when reporting therapeutic outcomes.