Dissatisfaction After Trifocal IOL Implantation and Its Improvement by Selective Wavefront-Guided LASIK.

PURPOSE: To evaluate a substantially improved wavefront acquisition technique (Peramis; SCHWIND eye-tech-solutions, Kleinostheim, Germany) for selective wavefront-guided aberration correction to improve satisfaction after implantation of trifocal intraocular lenses (IOLs). METHODS: Of 213 eyes from 108 consecutive patients receiving cataract surgery with multifocal IOL implantation (FineVision; PhysIOL, Liége, Belgium), 56 eyes (26%) of 42 dissatisfied patients were treated with selective wavefront-guided laser in situ keratomileusis (LASIK) (Amaris 1050; SCHWIND eye-tech-solutions) free of cost with a follow-up of 12 months. Selective wavefront-guided ablation corrected for all aberrations except spherical aberrations to preserve the apodization and therefore to enhance the multifocal effect. The degree of satisfaction after trifocal IOL implantation, its increase after selective wavefront-guided LASIK, and the refractive error (spherical equivalent, refractive astigmatism) before and after selective wavefront-guided LASIK were evaluated. RESULTS: Refractive astigmatism of greater than 0.50 diopters (D) was the most frequent residual refractive error (63%), followed by myopia (45%), hyperopia (20%), and increased ocular higher order aberrations (13%). After selective wavefront-guided LASIK, the refractive target (±0.50 D) was achieved in 98% and refractive astigmatism was 0.50 D or less in 93% of the eyes operated on. The overall satisfaction score in dissatisfied patients increased from 2.1 ± 0.8 preoperatively to 3.6 ± 0.8 (out of 4). Eighty-eight percent of initially dissatisfied patients would choose this procedure again. CONCLUSIONS: Selective wavefront-guided LASIK reduced refractive errors and significantly increased spectacle independence and satisfaction, which may lead to a better acceptance of trifocal IOLs. [J Refract Surg. 2019;35(6):346-352.].

Intrastromal application of riboflavin for corneal crosslinking.

PURPOSE: To experimentally evaluate the efficacy of corneal crosslinking (CXL) by injecting the photomediator riboflavin into the corneal stroma via intrastromal channels. METHODS: Five groups of pig corneas, nine each, were compared regarding stress-strain relationship and UV-absorption. Group 1 had intrastromal channels floated with riboflavin 0.5%-solution followed by UVA-irradiation (3 mW/cm(2) for 30 minutes); group 2 was handled like group 1, but were irradiated with 9 mW/cm(2) for 10 minutes; group 3 was treated according to the Dresden protocol (epi-off, 9 mW/cm(2) for 10 minutes); group 4 had the identical channel system, no riboflavin but identical irradiation; group 5 with native corneas served as a control group. The intrastromal channels were created with a femtosecond laser. The stress-strain relations were measured in corneal strips using a uniaxial material tester at strains up to 12%. The UV-transmission of the corneas was measured in groups 1, 3, and 5. RESULTS: The stress needed for a 10% strain was significantly increased by 82% in the corneas treated with the Dresden protocol compared with native cornea (P = 0.0005). With intrastromal application of riboflavin the significant increase was 87% (P = 0.0005) in group 1 and 64% (P = 0.007) in group 2. The channel formation alone did not alter biomechanics (P = 0.923). The corneal UVA-transmission was 2.4% after intrastromal riboflavin application, 8.9% after the treatment according to the Dresden protocol, and 57.9% in native corneas. CONCLUSIONS: The experiments demonstrate the intrastromal application of riboflavin by means of intrastromal channels a feasible "epi-on" approach for CXL. More experimental data are needed before clinical testing.