SBIR-STTR Award

We intend to generate prescribed negative cylinder excimer laser ablations using technology analogous to that presently being used for the correction of myopia in human clinical trials. The device would correct high amounts of astigmatism for which treatment with glasses and contact lenses is problematic because of induced binocular vision problems due to poor lens orientation. A prototype device for generating prescribed cylindrical ablations will be developed and evaluated on PMMA test surfaces to test for the accuracy and reliability of system function. Alignment techniques, which provide for axis orientation and ablation centering, will also be evaluated. A prototype instrument is presently being developed and should be operational by the time of funding. The device will provide for meridional adjustment of 1/3 degree intervals, slit width adjustment within 9 u per step and precise rate of closure. The design in intended to exceed the expected and patient ablation tolerances of + 0.25 D and + 2.0 degrees. PMMA testing will be carried out on two types of surfaces, flat samples and spherical contact lenses. For the samples having cylindrical component, the power of the prescribed ablation cylinder will be equal to the complement of the sample cylinder. Thus, reduction of the cylindrical component to zero would provide verification of the ablation model, and residual cylinder would indicate an error in the ablation algorithm, hardware, or alignment procedures. For clinical application eye alignment procedures will be developed during that latter phases of the project. This work will be carried out in parallel with the other studies.Awardee's statement of the potential commercial applications of the research:The market potential for accurate, effective, and safe photorefractive technology is self evident. Therapeutic applications offer the greatest benefit to risk ratio. This grant application is intended to expedite the use of this technology in the therapeutic arena.National Eye Institute (NEI)

During Phase I VISX developed hardware and software for an excimer laser system that enables it to correct hyperopic refractive errors. The potential market for such a system includes many people with hyperopia that cannot be corrected with glasses or contact lenses, and eventually, perhaps, other hyperopic patients who might choose to undergo photorefractive keratectomy (PRK). We have demonstrated that our proprietary excimer PRK system for hyperopic correction can sculpt surfaces that match theoretical lens equations. For Phase II, we now propose to complete the optimization and testing of the system. We propose: l) To engineer the incorporation of the new hyperopic instrumentation into the Twenty/Twenty(R) laser system in preparation for pre-clinical testing. 2) To optimize the efficacy of the system with pre- clinical studies on African Green monkeys. A special feature of the system is the ability to alter, under software control, the size and shape of the transition zone surrounding the central refractive correction. We will use this capability to adjust the ablation parameters for optimal performance. 3) To revise the software and hardware designs for the hyperopia module in preparation for clinical testing