PRK using an absorbing cell delivery system for correction of ...

An ophthalmic laser unit with a Lambda-Physik LPX excimer emitting 193 nm and a unique beam shaping system was designed at the Complex "Eye Microsurgery." An absorbing cell, used as the main element of the delivery system, allowed us to obtain a precise profile of the laser energy density on the patient's cornea, smoothly changing the corneal refraction with each shot in the whole ablation area. The absorbing cell also allowed for varying the shape of distribution of radiation energy density depending on the patient's corneal shape. We performed more than 7000 photorefractive keratectomy laser operations in myopic patients, and report results in 3251 myopic eyes (approximately 46%) from -4.00 to -26.00 D, up to 4 years after surgery. In eyes with myopia greater than 6.00 D, emmetropia was obtained in 48% of cases; 42% had a residual mild myopia within 5.00 D; and 12% had a residual myopia more than 3.00 D. The corneal haze disappeared in 48.8% of cases; haze not affecting the visual acuity remained in 39%; and clinically significant haze remained in 12.2%. These eyes required a powerful medication or repeated PRK. After surgery, 87.7% of patients needed no spectacle correction. Excimer laser PRK with the use of the forming system efficiently corrects high myopia.