Influence of macular pigment on the sensitivity to discomfort glare from daylight.

Understanding the factors that influence the human perception of glare is necessary to properly address glare risks in buildings and achieve comfortable visual environments, especially in the workplace. Yet large inter-individual variabilities in glare perception remain unexplained and thus uncovered by the current empirical glare models. We hypothesize that this variability has an origin in the human retina, in particular in the density of macular pigments present in its central area, which varies between individuals. Macular pigments are known to absorb blue light and attenuate chromatic aberration, thus reducing light scatter. This study presents the outcomes of the first experiment ever conducted in a daylit office environment, in which glare sensitivity and macular pigment density were measured and compared for 110 young healthy individuals, along with other ocular parameters. The participants were exposed to different glare conditions induced by the sun filtered through either color-neutral or blue-colored glazing. In neutral daylight conditions with sun disc in the near periphery, neither macular pigment nor any other investigated ocular factors have an impact on discomfort glare perception whereas glare perception in conditions with the blue-colored sun disc in the near periphery was found to be correlated with macular pigment optical density.

Clinical Classification of Acquired Concomitant Esotropia.

BACKGROUND: Classification and management of acquired concomitant esotropia is controversial. We sought to establish a simple clinical classification in order to determine in which cases further investigations in search of underlying pathologies are necessary. PATIENTS AND METHODS: Observational retrospective study of the files of 175 consecutive patients examined in our unit between 2009 and 2018 for acute convergent strabismus. One hundred and nine patients were selected, after exclusion of infantile, incomitant, or mechanical esotropias, residual esotropias, and patients examined on a single occasion. All patients received a complete orthoptic and ophthalmological examination. We grouped the patients according to their common characteristics. RESULTS: We established the following categories: 1. Acute esotropia of large angle (20 to 45 prism diopters [PD]), accompanied by mild hyperopia (mean 1.2 D) in children (n = 16) and moderate myopia (mean 3.7 D) in adolescents and adults (n = 13). 2. Decompensated micro-esotropia, which is distinguished from the other categories by the presence of abnormal retinal correspondence (n = 33). 3. Decompensated esophoria, with intermittent deviations of 5 to 30 PD, esotropia being compensated part of the time (n = 25). 4. Esotropia present only at a distance in patients over 50 years of age (n = 20). 5. Small-angle esotropia (< 15 PD) greater at a distance, associated with oculomotor cerebellar syndrome (n = 2). Complementary examinations (MRI or CT scan) were performed on 21 patients, leading to the discovery of a posterior fossa astrocytoma in a 4-year-old boy. CONCLUSIONS: The recognition of decompensated micro-esotropia and esophoria, as well as distance esotropia of the elderly, avoids unnecessary additional investigations, which are indicated in any type of acute comitant strabismus if associated with any neurological sign or symptom (e.g., headaches, nausea, vertigo, imbalance, poor coordination, nystagmus, or papilledema). In the absence of neurological findings, there is no consensus about the indication of neuroimaging in large-angle acquired concomitant esotropia, but long-term follow-up of patients that do not undergo neuroimaging is strongly recommended in order to identify later occurring intracranial diseases. This is of particular importance with children.