Safety and efficacy of an intraocular Fresnel prism intraocular lens in patients with advanced macular disease: initial clinical experience.

PURPOSE: To perform a pilot study of a new in-the-bag Fresnel prism intraocular lens (IOL) designed to deviate the image from diseased to healthy retina in eyes with bilateral age-related macular degeneration (AMD). SETTING: Anterior segment subspeciality practice, Pretoria, South Africa. DESIGN: Prospective nonmasked trial. METHOD: Cataract surgery and unilateral implantation of the prismatic IOL were performed in patients with bilateral AMD and cataract. Outcomes were surgical complications, subjective and objective visual improvement, and undesirable optical effects. RESULTS: Three eyes of 3 patients were evaluated. All patients reported displacement of the scotoma, and no patient reported diplopia. The only complication was posterior capsule opacification (1 eye). CONCLUSIONS: Patients noted improved vision and no diplopia. This pilot was performed using a prototype IOL with single power and single angle of deviation; however, there is scope for individual patient optimization. This new technology merits further research and development because it may benefit large numbers of patients with stable end-stage AMD. FINANCIAL DISCLOSURE: Dr. Claoué has a financial interest in the patent controlling the Fresnel prism IOL. Dr. Potgieter has no financial or proprietary interest in any material or method mentioned.

Prediction of flap response.

PURPOSE: To find predictors of the induced biomechanical and optical effects of lamellar flap creation on the cornea. SETTING: Optimed Eye and Laser Clinic, Pretoria, South Africa, and the Department of Ophthalmology and Biomedical Engineering Center, The Ohio State University, Columbus, Ohio, and Bausch & Lomb Vision Research Laboratory, Rochester, New York, USA. METHODS: This prospective study monitored the refractive, wavefront aberration, and corneal topographic changes in 29 eyes of 15 patients for 3 months after the creation of a corneal lamellar flap. The main outcome measures for statistical analysis were refraction, total corneal thickness, residual corneal bed thickness, horizontal white-to-white corneal diameter, horizontal flap diameter, topography data, and wavefront data. RESULTS: Statistically significant changes were seen in the autorefraction mode. Wavefront data showed significant change in 4 Zernike modes-90/180-degree astigmatism, vertical coma, horizontal coma, and spherical aberration. The topography data indicated the corneal biomechanical response was significantly predicted by stromal bed thickness in the early follow-up period and by total corneal pachymetry and flap diameter in a 2-parameter statistical model in the late follow-up period. CONCLUSIONS: Uncomplicated lamellar flap creation is responsible for systematic changes in corneal topography and induction of higher-order optical aberrations. Predictors of this response include stromal bed thickness, flap diameter, and total corneal pachymetry.