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.
