Sensibilidad al contraste en edad pediátrica / Contrast sensitivity in pediatric ages

La sensibilidad al contraste es considerada como la capacidad de discriminar diferencias de iluminación entre áreas adyacentes, cuyo umbral se estima como la menor cantidad de contraste que se necesita para lograr esta distinción. La medida de la agudeza visual cuantifica la visión en alto contraste; sin embargo, los objetos que nos encontramos en la vida real no son solo de alto contraste, sino que presentan diferentes niveles de contraste y tamaño, lo cual puede ser determinado con el estudio de la sensibilidad al contraste, ya sea a través de cartillas de bajo contraste o de las pruebas que evalúan las frecuencias espaciales, que serán utilizadas según la edad del paciente pediátrico. Con este trabajo se pretende mostrar los diferentes criterios relacionados con la sensibilidad al contraste en edades pediátricas, para lo cual se realizó una búsqueda en diferentes publicaciones y textos de la especialidad. Existe controversia relacionada con la edad pediátrica en la cual se alcanza la sensibilidad al contraste al nivel del adulto, así como los valores normativos en la infancia con las diferentes pruebas empleadas. La valoración de la sensibilidad al contraste constituye una herramienta más para evaluar la función visual conjuntamente con la determinación de la agudeza visual y la visión de colores. Se necesitan más estudios sobre este tema para unificar criterios con el fin de perfeccionar la atención a la población pediátrica(AU)

Contrast sensitivity is the ability to distinguish differences in luminance between adjacent areas. Its threshold is estimated as the smallest amount of contrast needed to achieve such a distinction. Visual acuity measurement quantifies high contrast vision. However, the objects around us are not only characterized by high contrast: they display different levels of contrast and size, which may be determined through the study of contrast sensitivity, either with low contrast charts or spatial frequency tests, to be used according to the pediatric patient's age. The purpose of the study was to present various criteria about contrast sensitivity in pediatric ages. To achieve this end, a search was conducted in different publications and texts from the specialty. A debate is currently in progress about the pediatric age in which adult contrast sensitivity is achieved and the standard values to be verified with the different tests applied in childhood. Contrast sensitivity assessment is one more tool to evaluate visual function and determine visual acuity and color vision. Further studies are required about the subject aimed at unifying criteria so as to improve the care of the pediatric population(AU)

Contrast Sensitivity and Color Vision Comparison Between Clear and Yellow-Tinted Intraocular Lens in Diabetic Retinopathy

PURPOSE: To compare contrast sensitivity and color vision after implantation of a clear intraocular lens (IOL) and a yellow-tinted IOL in diabetic retinopathy patients. METHODS: In the 50 eyes of 25 diabetic patients with non-proliferative diabetic retinopathy, clear IOLs were implanted in 25 eyes, and yellow-tinted IOLs were implanted in 25 fellow eyes. Three months after the surgery, contrast sensitivity function was measured with a vision contrast test system, and color discrimination was tested using the Farnsworth Munsell 100-hue test. RESULTS: Eyes implanted with yellow-tinted IOLs had significant differences in contrast sensitivity values compared to those of fellow eyes implanted with clear IOLs in both the moderate diabetic retinopathy group (6.0 cycles per degree) and the severe diabetic retinopathy group (throughout all spatial frequencies except 12.0 cycles per degree). The yellow-tinted IOL did not modify chromatic discrimination compared with that of the clear IOL. In the blue-yellow axis error score, however, there were significant differences between the clear IOL and the yellow-tinted IOL. CONCLUSIONS: With progressing diabetic retinopathy, the yellow-tinted IOL provided better contrast sensitivity than the clear IOL. The yellow-tinted IOL improved color vision in the blue-yellow chromatic axis without causing chromatic discrimination defects.

Comparison of Visual Function Among Aspheric Intraocular Lenses

PURPOSE:To compare the visual function among 3 aspheric intraocular lenses (IOLs) after cataract surgery. METHODS: A prospective analysis among 70 eyes of 68 patients who had undergone phacoemulsification and implantation of aspheric IOLs (Acrysof IQ, 30 eyes; Tecnis ZA9003, 20 eyes; Akreos Adapt-AO, 20 eyes) was performed. The best corrected visual acuity (BCVA), refraction, coma, trefoil, spherical aberration, root-mean-square (RMS), contrast sensitivity test, satisfaction and glare was evaluated during the follow-up period of 3 months. RESULTS: There were no significant differences in BCVA, satisfaction, glare, coma, trefoil, RMS and contrast sensitivity test among the 3 aspheric IOLs. Spherical aberration in Akreos Adapt-AO (0.04+/-0.05 microm) was higher compared with Acrysof IQ (0.03+/-0.04 microm) and Tecnis ZA9003 (0.11+/-0.03 microm)(p<0.01). The predictability of postoperative spherical equivalent in the Akreos Adapt-AO group (-0.57+/-0.22D) represented a statistically significant myopic refractive error compared with the Acrysof IQ (0.01+/-0.77D) and the Tecnis ZA9003 (-0.20+/-0.71D) groups (p=0.04). CONCLUSIONS: There were no significant differences in visual function except spherical aberration, which was highest in the Akreos Adapt-AO group.

Reproducibility of Morphoscopic Contrast Sensitivity Obtained with the Visual Capacity Analyzer in Glaucoma Patients

PURPOSE: To determine the reproducibility of morphoscopic contrast sensitivity test values in the patients with primary open angle glaucoma using the Visual Capacity Analyzer (ACV) designed for assessing full visual performance including contrast sensitivity. METHODS: Morphoscopic contrast sensitivity was measured in each five glaucomatous eyes. The measurement was repeated 5 times under two different luminance level of screen (maximum and 3 cd/m2). RESULTS: Under maximum luminance background, the coefficients of variation (CV) and the reliability coefficients (RC) for the spatial frequencies examined in this study ranged from 2.1% to 29.3%, from 92.1% to 100.0%, respectively. Under 3cd/m2 luminance level of screen, the CV ranged from 2.7% to 32.0%, and the RC ranged from 90.7% to 99.9%. CONCLUSIONS: The results indicates that for the spatial frequencies examined, the morphoscopic contrast sensitivity test using ACV shows good reproducibility in glaucomatous patients.

Clinical Results of AMO ARRAY Multifocal Intraocular Lens

Various kinds of multifocal intraocular lenses(IOLs) have been developed for the improvement of near and far visual acuity after cataract operation. This prospective study was performed to compare a function of AMO ARRAY multifocal IOL(Array group) with conventional monofocal IOL(Mono group). Each type of IOL was implanted into 25 eyes and uncorrected visual acuity(UCVA) and best corrected visual acuity(BCVA) at near, intermediate and far distance were evaluated before and 2 months after operation in both groups. Contrast sensitivity, photophobia and glare were also evaluated as subjective symptoms in both groups. Mean UCVA at distant and near distance before operation was 0.23+/-0.15 and 0.25+/-0.20 in mono group, and 0.13+/-0.11 and 0.14+/-0.11 in Array group. Mean UCVA/BCVA at distant and near distance 2 month after operation was improved to 0.79+/-0.28/0.87+/-0.27 and 0.34+/-0.15/0.82+/-0.26 in mono group and 0.83+/-0.19/0.86+/-0.19 and 0.50+/-0.15/0.79+/-0.15 in Array group. The difference of UCVA at near distance was statistically significant(P<0.05), while that of BCVA at near and far distance was not statistically significant between two groups(P<0.05). Array group had less contrast sensitivity at all spatial frequencies(1.5, 3, 6, 12, 18 cycles/degree) and more glare than the mono group after operation. AMO ARRAY multifocal IOL induces a good result of visual rehabilitation in both near and far distance, but it may cause more glare and less contrast sensitivity than the monofocal IOL.