María Jesús Pérez-Carrasco

Effects of Light‐emitting Diode Radiations on Human Retinal Pigment Epithelial Cells In Vitro

Human visual system is exposed to high levels of natural and artificial lights of different spectra and intensities along lifetime. Light‐emitting diodes (LEDs) are the basic lighting components in screens of PCs, phones and TV sets; hence it is so important to know the implications of LED radiations on the human visual system. The aim of this study was to investigate the effect of LEDs radiations on human retinal pigment epithelial cells (HRPEpiC). They were exposed to three light–darkness (12 h/12 h) cycles, using blue‐468 nm, green‐525 nm, red‐616 nm and white light. Cellular viability of HRPEpiC was evaluated by labeling all nuclei with DAPI; Production of reactive oxygen species (ROS) was determined by H2DCFDA staining; mitochondrial membrane potential was quantified by TMRM staining; DNA damage was determined by H2AX histone activation, and apoptosis was evaluated by caspases‐3,‐7 activation. It is shown that LED radiations decrease 75–99% cellular viability, and increase 66–89% cellular apoptosis. They also increase ROS production and DNA damage. Fluorescence intensity of apoptosis was 3.7% in nonirradiated cells and 88.8%, 86.1%, 83.9% and 65.5% in cells exposed to white, blue, green or red light, respectively. This study indicates three light–darkness (12 h/12 h) cycles of exposure to LED lighting affect in vitro HRPEpiC.

Impaired Mesopic Visual Acuity in Eyes with Early Age-Related Macular Degeneration

PURPOSE To determine photopic and mesopic distance high-contrast visual acuity (HC-VA) and low-contrast visual acuity (LC-VA) in eyes with early age-related macular degeneration (AMD). METHODS Measurements were made in 22 subjects with early AMD and 28 healthy control subjects. Inclusion criteria included a photopic HC-VA of 20/25 or better. Distance VA was measured using HC (96%) and LC (10%) Bailey-Lovie logMAR letter charts under photopic (85 cd/m(2)) and mesopic (0.1-0.2 cd/m(2)) luminance conditions. RESULTS Mean mesopic distance HC-VA and LC-VA were significantly worse (0.1 logMAR and 0.28 logMAR, respectively) in the early AMD group than in the control group. Under mesopic conditions, the mean difference between LC-VA and HC-VA was significantly greater in the early AMD (0.45 logMAR) than the control group (0.27 logMAR). Mean differences between mesopic versus photopic HC-VA and mesopic versus photopic LC-VA were significantly greater in the early AMD than the control group (0.13 and 0.32 logMAR of difference between the means, respectively). Sensitivity and specificity were significantly greater for mesopic LC-VA than for mesopic HC-VA (Receiver Operating Characteristics, area under the curve [AUC], 0.94 ± 0.030 and 0.76 ± 0.067, respectively). AUC values for photopic HC-VA and LC-VA were below 0.70. CONCLUSIONS Visual acuity testing under low luminance conditions emerged as an optimal quantitative measure of retinal function in early AMD.

Normal Values for the Size of a Halo Produced by a Glare Source

PURPOSE To determine the size of a halo in the visual field induced by bright light in healthy eyes of all ages using the Vision Monitor (MonCv3; Metrovision, Pérenchies, France) and to assess the repeatability of the method. METHODS Measurements were made in the right eyes of 147 healthy subjects (mean age: 48.2 ± 16.2 years) who were classified into six age groups. Using the Vision Monitor, optotypes of low luminance were presented at a distance of 2.5 m. The visual angle subtended by the radius of the halo was calculated in minutes of arc (arc min). The repeatability of the method was determined in a subset of 37 subjects older than 50 years by calculating the Bland-Altman coefficient of repeatability. RESULTS The mean radius of the halo was 111.6 ± 39.8 arc min. Halo radius started to increase significantly from the age of 50 to 59 years. The relationship between halo radius and age (r = 0.65; P < .0001) was described by fitting a power function to the data. Halo size was independent of gender. The coefficient of repeatability of the method was ±44 arc min. CONCLUSIONS Halo size increases with age following a power model. The normal halo size values provided could help clinicians distinguish between normal or abnormal glare problems. The intersession repeatability observed for halo size measurement indicates this method could be useful for assessing visual impairment caused by glare.

Relationship between macular pigment and visual acuity in eyes with early age-related macular degeneration.

Purpose:  Today the extent to which MP impacts visual function in early AMD remains unclear. This study examines the relationship between macular pigment optical density (MPOD) and high‐contrast visual acuity (HC‐VA) and low‐contrast visual acuity (LC‐VA) in eyes with early age‐related macular degeneration (AMD).

Disk halo size measured in individuals with monofocal versus diffractive multifocal intraocular lenses.

Purpose To compare disk halo size in response to a glare source in eyes with an aspheric apodized diffractive multifocal intraocular lens (IOL) or aspheric monofocal IOL. Setting Rementeria Ophthalmological Clinic, Madrid, Spain. Design Prospective randomized masked study. Method Halo radius was measured using a vision monitor (MonCv3) with low‐luminance optotypes in eyes that had cataract surgery and bilateral implantion of an Acrysof Restor SN6AD1 multifocal IOL or Acrysof IQ monofocal IOL 6 to 9 months previously. The visual angle subtended by the disk halo radius was calculated in minutes of arc (arcmin). Patient complaints of halo disturbances were recorded. Monocular uncorrected distance visual acutity (UDVA) and corrected distance visual acuity (CDVA) were measured using high‐contrast (96%) and low‐contrast (10%) logMAR letter charts. Results The study comprised 39 eyes of 39 subjects (aged 70 to 80 years); 21 eyes had a multifocal IOL and 18 eyes a monofocal IOL. The mean halo radius was 35 arcmin larger in the multifocal IOL group than the monofocal group (P < .05). Greater halo effects were reported in the multifocal IOL group (P < .05). The mean monocular high‐contrast UDVA and low‐contrast UDVA did not vary significantly between groups, whereas the mean monocular high‐contrast CDVA and low‐contrast CDVA were significantly worse at 0.12 logMAR and 0.13 logMAR in the multifocal than in the monofocal IOL group, respectively (P < .01). A significant positive correlation was detected by multiple linear regression between the halo radius and low‐contrast UDVA in the multifocal IOL group (r = 0.72, P < .001). Conclusions The diffractive multifocal IOL gave rise to a larger disk halo size, which was correlated with a worse low‐contrast UDVA. Financial Disclosure None of the authors has a financial or proprietary interest in any material or method mentioned.

Relationship between halo size and forward light scatter

Purpose To determine the relationship between the size of a halo induced by a glare source and forward scatter or visual acuity (VA) in healthy eyes. Method Measurements were made in the right eyes of 51 healthy individuals of mean age 29.3±7.5 years. Halo radius was measured using the Vision Monitor and low luminance (1 cd/m2) optotypes presented at a distance of 2.5 m. The visual angle subtended by the radius of the halo was calculated in minutes of arc (arc min). Forward scatter or, straylight, was measured using the compensation comparison technique. Best-corrected distance VA was measured using high contrast (HC) (96%) and low contrast (LC) (10%) Bailey-Lovie logMAR letter charts under photopic (85 cd/m2) and mesopic (0.15 cd/m2) luminance conditions. Results Mean halo radius was 202±43 arc min (3.4±0.7°) and mean retinal straylight was 0.95±0.12 log units. Mean photopic distance HC-VA and LC-VA were −0.02±0.06 and 0.12±0.09 logMAR, respectively. Mean mesopic distance HC-VA and LC-VA were 0.35±0.11 and 0.74±0.11 logMAR, respectively. Forward stepwise regression analysis revealed that halo radius was significantly correlated with straylight (r=0.45) and mesopic LC-VA (r=0.48), but not with photopic HC-VA and/or LC-VA and mesopic HC-VA. Conclusions In healthy eyes, the larger the halo size induced by a given glare source, the greater the forward-scatter (straylight) and worse the mesopic LC-VA. Halo size seems to be independent of photopic HC-VA or LC-VA and mesopic HC-VA.

Photoprotective Effects of Blue Light Absorbing Filter against LED Light Exposure on Human Retinal Pigment Epithelial Cells In Vitro

Abstract Background: Over the recent years, several researches have speculated about the effects of Light Emitting Diodes (LEDs) radiation on retinal epithelium cells (RPE). Worldwide, most people live exposed to LEDs irradiation incorporated in screens of PCs, phones and TV sets. These lights give rise to the formation of reactive oxygen species and induce mutagenic mechanisms which lead to apoptosis and consequently to degenerative eye diseases, such as age-related macular degeneration (AMD). Thus, it is a priority interest to develop appropriate solutions for the growing industry field of LED light phototoxicity. The aim of this study was to investigate the protective effects of blue light absorbing filters in order to decrease induced apoptosis on human retinal pigment epithelial cells. Methods: Human retinal pigment epithelial cells were exposed to 3 light-darkness (12 hours/12 hours) cycles of white (Ta5400°K), blue (468 nm), green (525 nm) and red (616 nm) LED light. Light irradiance was 5 mW/cm2. Oxidative stress was evaluated by H2DCFDA staining, mitochondrial membrane potential by TMRM staining, DNA damage by H2AX histone activation, apoptosis by caspase-3 activation, and cell viability by DAPI. Results: Our results have shown that the use of a blue light absorbing filter decreased cellular apoptosis by 56-89% and DNA damage by 57-81%. A decrease in ROS level production and an increase in cellular viability was also obtained. Conclusion: This study suggests that blue light absorbing filters may protect against LED lighting photo toxicity and, consequently, provides a photo protector effect.

Macular Thickness and Mesopic Visual Acuity in Healthy Older Subjects

ABSTRACT Purpose/Aim: Impaired mesopic visual acuity (VA) is a risk factor for incident early age-related macular degeneration (AMD) This study examines relationships between macular thickness measurements and photopic or mesopic VA in healthy eyes. Materials and Methods: In 38 young and 39 older healthy individuals, total, inner, and outer retinal layer (IRL and ORL) thicknesses were measured in the macula region through spectral-domain optical coherence tomography (SD-OCT). Measurements were made across three subfields centered at the fovea: central foveal, pericentral, and peripheral. Best-corrected distance high-contrast (HC) and low-contrast (LC) VA were measured using Bailey-Lovie logMAR letter charts under photopic and mesopic luminance conditions. In addition, the low luminance deficit in VA (LLD, difference between photopic and mesopic VA) was calculated. Relationships were examined through Spearman correlation in each age group and through multiple linear regressions across all eyes. Results: No significant correlations were detected between photopic VA (HC-VA and LC-VA) and macular thickness measurements in each age group. In mesopic conditions, age and pupil size were independent predictors of HC-VA (p = 0.001) and age and pericentral ORL thickness predictors of LC-VA (p = 0.001). Central foveal thickness emerged as the unique independent predictor of LLD (HC-VA, p = 0.013 and LC-VA, p = 0.005). Only in the older age group, was central foveal thicknesses correlated with LLD (HC-VA, r = + 0.45; p = 0.004 and LC-VA, r = + 0.33, p = 0.038). Conclusions: Greater macular thicknesses were related to worse mesopic VA and low luminance deficit in healthy subjects.

Espesor macular medido con tomografía de coherencia óptica en ojos pseudoafáquicos con implante amarillo vs. transparente

OBJECTIVE To study the use of optical coherence tomography (OCT), for measuring the macular thickness variations produced over time in elderly pseudophakic subjects implanted with a clear intraocular lens (IOL) in one eye, and a yellow IOL in the other eye. METHODS Macular thickness measurements were obtained in the 36 eyes of 18 subjects over 65 years, with cataracts surgically removed from both eyes and implanted with different absorbance (clear and yellow) IOLs in 2 separate surgeries. Stratus-OCT was used to determine the macular thickness in 2 sessions with 5 years of difference. RESULTS After 5 years of follow-up, the eyes implanted with clear IOLs revealed a significant decrease in macular thickness. However, in eyes implanted with yellow IOLs the macular thickness remained stable. The mean overall decrease in macular thickness in eyes implanted with clear IOLs was 5 ± 8 μm (P=.02), and foveal thickness reduction was 10 ± 17 μm (P=.02). CONCLUSIONS The macular thickness changes produced in eyes implanted with a yellow IOL differ from those with a clear IOL. These observation point to a possible protective effect of yellow IOL against the harmful effects of light in elderly pseudophakic subjects. However, studies with a longer follow-up are still needed to confirm that the protection provided by this IOL model is clinically significant.