SBIR-STTR Award

Therapeutic applications of excimer photorefractive keratectomy (PRK) are limited by epithelial regrowth mechanism that produce a flattening of the cornea. This physiological healing response can cause a high degree of hyperopia to result in patients who have avoided corneal transplants by having had anterior corneal scars and irregularities removed with excimer laser treatment. Patients manifesting large amounts of hyperopic astigmatism, e. g. from eye surgery, could benefit from excimer PRK astigmatic treatment, but would be left with an overall hyperopic correction due to the excimer PRK flattening of the steeper meridian. Current methods of sculpturing the cornea with excimer lasers are not versatile enough to produce the complex types of ablations necessary to stop flattening from epithelial regrowth. Since the regrowth flattening is in response to edges in the stroma, stable hyperopic excimer PRK also requires complex contouring at the edge of the ablation zone. We will develop prototype instrumentation for generating complex ablations to be used in hyperopic excirner PRK procedures. It will be tested on plastic to evaluate the predictability and reliability of the system. Animal studies will be conducted in Phase II.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 will 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 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 will complete the optimization and testing of the system. We will engineer the incorporation of the new hyperopic instrumentation into the Twenty/Twenty) laser system in preparation for pre-clinical testing. We will 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. Finally, we will revise the software and hardware designs for the hyperopia module in preparation for clinical testing.Awardee's statement of the potential commercial applications of the research: The market potential for accurate, effective and safe photorefractive technology is large. This project seeks to correct hyperopic effects of phototherapeutic procedures that may benefit many thousands of patients. In addition, over 56 million Americans wear positive power corrective lenses.National Eye Institute (NEI)