Search results for "Mesopic Vision"
showing 5 items of 45 documents
Visual performance with multifocal intraocular lenses
2004
Abstract Objective To evaluate distance and near visual performance under bright (photopic) and dim (mesopic) conditions in patients who had undergone uncomplicated cataract extraction with multifocal or monofocal intraocular lens (IOL) implantation. Design Prospective, nonrandomized, masked, comparative, observational case series. Participants Thirty-two eyes of 32 patients after zonal-progressive multifocal IOL implantation (Allergan Medical Optics Array SA-40N) and 32 eyes of 32 age-matched patients after monofocal IOL implantation (Allergan Medical Optics SI-40NB). Intervention All eyes underwent phacoemulsification and IOL implantation. Main outcome measures At 18 months after surgery,…
Effect of the color of the intraocular lens on optical and visual quality
2014
Purpose: To analyze the optical quality of intraocular lenses (IOL) with an orange (PC440Y) and a yellow (SN60AT) filter, and correlate these results with the visual quality of patients with these implants. Setting: Fisabio Oftalmología Médica, Valencia, Spain. Design: Randomized prospective study. Materials and Methods: The IOL optical quality was determined using the modulation transfer function (MTF) and the spectral transmission. The visual quality of 87 eyes with cataract (51 with orange filter and 36 with yellow filter) was determined by best corrected visual acuity (BCVA) and contrast sensitivity function (CSF) under photopic and mesopic conditions. To analyze the results, we use a S…
Color discrimination under mesopic conditions in cats and humans
1995
The ability to discriminate colors under various levels of mesopic illumination was studied in three cats using colored papers as stimuli and with a computer controlled training schedule. Discrimination based on brightness differences was prevented using a new method in which illuminant color was varied. The luminance threshold for color discrimination in cats was found to be 0.5 cd/m2, close to the cone threshold reported by others from ganglion cell recordings. The same experiment was carried out with human subjects and revealed a luminance threshold of 0.00042 cd/m2 for color discrimination.
Effect of Varying Levels of Glare on Contrast Sensitivity Measurements of Young Healthy Individuals Under Photopic and Mesopic Vision
2018
Contrast sensitivity (CS), the ability to detect small spatial changes of luminance, is a fundamental aspect of vision. However, while visual acuity is commonly measured in eye clinics, CS is often not assessed. At issue is that tests of CS are not highly standardized in the field and that, in many cases, optotypes used are not sensitive enough to measure graduations of performance and visual abilities within the normal range. Here, in order to develop more sensitive measures of CS, we examined how CS is affected by different combinations of glare and ambient lighting in young healthy participants. We found that low levels of glare have a relatively small impact on vision under both photopi…
The Impact on Vision of Aspheric to Spherical Monofocal Intraocular Lenses in Cataract Surgery
2013
Purpose To provide a summary of the impact on vision of an aspheric intraocular lens (IOL) compared with a spherical IOL in cataract surgery. Design Systematic review with meta-analysis. Participants Patients from published randomized controlled trials (RCTs) of cataract surgery with aspheric compared with spherical monofocal IOL implantation. Methods We systematically searched the peer-reviewed literature in MEDLINE, EMBASE, Web of Science, BIOSIS, and the Cochrane Library according to the Cochrane Collaboration method to identify relevant RCTs. The inclusion criteria were RCTs on cataract surgery comparing the use of aspheric versus spherical IOL implantation that assessed visual acuity, …