Combined Cataract and Refractive Corneal Inlay Implantation Surgery: Comparison of Three Techniques.

PURPOSE: To compare clinical outcomes of three different techniques of combined cataract and Presbia Flexivue Microlens refractive corneal inlay (Presbia Coöperatief U.A., Amsterdam, Netherlands) implantation surgery for presbyopia compensation over a 12-month follow-up. METHODS: In this comparative pilot study, 15 patients with bilateral cataract were allocated to one of three groups with a different combination of surgical steps (cataract surgery, intrastromal pocket creation, and inlay implantation). In the three-step group, the intracorneal pocket was created in the non-dominant eye, bilateral cataract surgery was performed 3 months later, and the intracorneal inlay was inserted 3 months after that. In the two-step at 3 days group, bilateral cataract surgery was performed 3 days after pocket creation and inlay implantation in the non-dominant eye. In the two-step at 3 months group, the pocket creation and the inlay implantation were performed in the non-dominant eye 3 months after bilateral cataract surgery. Visual, refractive, and contrast sensitivity outcomes were evaluated and compared between the three groups. RESULTS: Twelve months after the inlay implantation, mean monocular uncorrected distance visual acuity was 20/32 in the three-step group, 20/32 in the two-step at 3 days group, and 20/25 in the two-step at 3 months group. Achieved mean monocular uncorrected near visual acuity was similar in the three groups (20/25). The visual and refractive outcomes did not show significant differences between groups. Contrast sensitivity was similar between groups under mesopic and photopic conditions. No intraoperative or postoperative complications were observed. CONCLUSIONS: Clinical outcomes of three different techniques of combined cataract surgery and refractive corneal inlay implantation had no apparent differences between them. The corneal inlay provided excellent near vision acuity, with high patient satisfaction and a high spectacle independence rate after cataract surgery. [J Refract Surg. 2016;32(5):318-325.].

Visual outcomes and safety of a refractive corneal inlay for presbyopia using femtosecond laser.

PURPOSE: To evaluate the outcomes and safety of a refractive inlay (Flexivue Micro-Lens, Presbia Coöperatief U.A.) for the corneal compensation of presbyopia. METHODS: This prospective, interventional clinical study comprised 47 emmetropic presbyopes with a mean age of 52±4 years (range: 45 to 60 years). The inlay was inserted, centered on the line of sight, inside a corneal pocket created in the patient's nondominant eye, using a femtosecond laser. Follow-up was 12 months. Visual acuity, corneal topography, wavefront aberrometry, contrast sensitivity, structural corneal alterations, and questionnaires were evaluated. RESULTS: Twelve months after surgery, uncorrected near visual acuity was 20/32 or better in 75% of operated eyes, whereas mean uncorrected distance visual acuity (UDVA) of operated eyes was statistically significantly decreased from 0.06±0.09 logMAR (20/20) (range: -0.08 to 0.26) preoperatively to 0.38±0.15 logMAR (20/50) (range: 0.12 to 0.8) (P<.001), and mean binocular UDVA was not significantly altered (P=.516). Seventeen patients lost one line of corrected distance visual acuity in the operated eye. No patient lost 2 lines in CDVA in the operated eye. Overall, higher order aberrations increased and contrast sensitivity decreased in the operated eye. No tissue alterations were found using corneal confocal microscopy. No intra- or postoperative complications occurred. CONCLUSIONS: Twelve months after implantation, the Flexivue Micro-Lens intracorneal refractive inlay seems to be an effective method for the corneal compensation of presbyopia in emmetropic presbyopes aged between 45 and 60 years old.

Oxygen and glucose distribution after intracorneal lens implantation.

PURPOSE: Insertion of an implant in the cornea to achieve corneal multifocality has been suggested as a solution for presbyopia. However, unresolved issues related to nutrient transport need to be resolved. Our aim was to find the best lens position and influence lens transport properties in order to optimize nutrient supply to corneal cells. METHOD: An axisymmetric corneal model was built to simulate the nutrient transport in the cornea. Oxygen and glucose concentrations were calculated for normal cornea and intracorneal lens wearing conditions. The simulation considers the different tissue layers (epithelium, stroma, and endothelium) as well as layer and solute concentration dependent consumption. RESULTS: The minimum oxygen tension in the cornea was found to be higher when the lens was placed at 3/4 of the corneal thickness. Moreover, in this position, the influence of the inlay diffusivity was smaller than at more anterior or posterior placements. The diffusivity of the inlay affects the way nutrients will be transported through the cornea. The threshold where glucose may diffuse through or around the implant was found to be 1/100th of the stromal diffusivity. CONCLUSIONS: Computational methods are especially attractive to study nutrient transport in the cornea due to the difficulties associated with in vivo or in vitro measurements. The exact parameters that dictate the corneal metabolism are not known. However, the combined analysis of oxygen and glucose distribution is valuable in order to predict the complex physiological changes that arise under intracorneal lens implantation.