Objective assessment of the effect of pupil size upon the power distribution of multifocal contact lenses.

AIM: To analytically assess the effect of pupil size upon the refractive power distributions of different designs of multifocal contact lenses. METHODS: Two multifocal contact lenses of center-near design and one multifocal contact lens of center-distance design were used in this study. Their power profiles were measured using the NIMO TR1504 device (LAMBDA-X, Belgium). Based on their power profiles, the power distribution was assessed as a function of pupil size. For the high addition lenses, the resulting refractive power as a function of viewing distance (far, intermediate, and near) and pupil size was also analyzed. RESULTS: The power distribution of the lenses was affected by pupil size differently. One of the lenses showed a significant spread in refractive power distribution, from about -3 D to 0 D. Generally, the power distribution of the lenses expanded as the pupil diameter became greater. The surface of the lens dedicated for each distance varied substantially with the design of the lens. CONCLUSION: In an experimental basis, our results show how the lenses power distribution is affected by the pupil size and underlined the necessity of careful evaluation of the patient's visual needs and the optical properties of a multifocal contact lens for achieving the optimal visual outcome

Regresión del defecto campimétrico en un paciente con glaucoma primario de ángulo abierto

Pocos estudios han podido demostrar la mejoría del campo visual tras una pérdida de sensibilidad de origen glaucomatoso. En la mayoría de ellos, las recuperaciones campimétricas se producían al comienzo del tratamiento hipotensor; y, en menos casos, fueron progresivas y/o evolucionaron en varios años. Se presenta el caso de un paciente de 46 años al que, en septiembre 1995, se diagnosticó glaucoma primario de ángulo abierto, siendo tratado con carteolol 2%. El seguimiento durante 7 años puso de manifiesto un importante grado de regresión de los defectos campimétricos, mostrando la importancia de la campimetría computarizada en el diagnóstico precoz y seguimiento del glaucoma.Just a few studies could demonstrate the improvement of the visual fields after a glaucoma-induced sensitive loss. In most of them, perimetric recoveries arose at the beginning of the hypotensor treatment and, in less cases, were progressive and/or evolved during several years. A case is presented involving a 46 years old patient who, in September 1995, was diagnosed of open angle primary glaucoma, being treated with carteolol 2%. Follow-up visits for 7 years showed certain degree of regression of the perimetric defects, showing the relevance of the automated perimetry in the early glaucoma diagnosis and follow-up examination