If the change is more gradual as the pupillary size increases within the treatment zone, than the benefit of further enlarging the optical zone, beyond a certain point, may be limited. Finally, it seems as if the authors' calculations are based on derived elevation data. Since in this study the optical zone was 5.0 mm and the pupillary size up to 7.0 mm, it is possible that the peripheral computed elevation data were associated with a significant degree of error. The Food and Drug Administration, to its credit, never approved the smaller optical zones previously available to our non-American counterparts. For many patients, the excimer laser is a miracle of modern medical science.
Most miracles come with some strings attached.
Effect of pupillary dilation on corneal optical aberrations after photorefractive keratectomy. Lynn M. Contrast sensitivity and glare disability after radial keratotomy and photorefractive keratectomy. Niesen U, Businger U, Hartmann P, Senn P, Schipper I. Glare sensitivity and visual acuity after excimer laser photorefractive keratectomy for myopia. Br J Ophthalmol. Schlote T, Kriegerowski M, Bende T, Derse M, Thiel HJ, Jean B. Mesopic vision in myopia corrected by photorefractive keratectomy, soft contact lenses and spectacles.