Visual acuity and contrast sensitivity screening with a new iPad application

We present a new iPad application (app) for a fast assessment of Visual Acuity (VA) and Contrast Sensitivity (CS) whose reliability and agreement was evaluated versus a commercial screening device (Optec 6500). The measurement of VA was programmed in the app in accordance with the Amblyopia Treatment Study protocol. The CS was measured with sinusoidal gratings of four different spatial frequencies: 3, 6, 12 and 18 cpd at the same contrast values of the Functional Acuity Contrast Test (FACT) included in the Optec 6500. Forty-five healthy subjects with monocular corrected visual acuities better than 0.2 logMAR participated in the agreement study. Bland-Altman analyses were performed to assess the agreement and Deming regressions to calculate Mean Differences (MDs) and Limits of Agreement (LoAs). Coefficients of reliability were 0.15 logMAR for our method and 0.17 logMAR for the ETDRS testing protocol. For testing the CS, our test showed no statistically significant differences compared with the FACT at any spatial frequency (p > 0.05). The MDs were lower than 0.05 log units for all spatial frequencies.This work was funded by 'Ministerio de Economia y Competitividad' - 'Spain' (Grants FIS2011-23175 and DPI2015-71256-R) and 'Generalitat Valenciana' - 'Spain' (Grants PROMETEOII/2014/072 and ACOMP/2014/180).Rodríguez-Vallejo, M.; Llorens Quintana, C.; Furlan, WD.; Monsoriu Serra, JA. (2016). Visual acuity and contrast sensitivity screening with a new iPad application. Displays. 44:15-20. https://doi.org/10.1016/j.displa.2016.06.001S15204

Meibomian Gland Morphology: The Influence of Structural Variations on Gland Function and Ocular Surface Parameters

Purpose: To objectively and quantitatively characterize meibomian gland morphology and to investigate the influence of morphological variations on gland function and ocular surface and tear film parameters. Methods: One hundred fifty subjects were enrolled. The examinations included tear osmolarity, tear meniscus height, bulbar conjunctival hyperemia, noninvasive tear film breakup time, lid margin thickness, foam secretion, meibomian gland expressibility, count of functioning glands, corneal and conjunctival staining, fluorescein breakup time, lid wiper epitheliopathy, and Schirmer test. Patient symptoms were assessed using the Ocular Surface Disease Index questionnaire. Images from noncontact meibography were analyzed using an automated method that objectively estimates dropout area, number of glands, gland length and width, and gland irregularity. Results: Gland irregularity highly correlated with dropout area (r = −0.4, P < 0.001) and showed significant partial correlations with fluorescein breakup time (r = 0.162, P = 0.049) and the Ocular Surface Disease Index questionnaire (r = −0.250, P = 0.002) Subjects with dropout area <32% were divided into 2 groups: high and low irregularity. Gland expressibility was statistically significantly different between the 2 groups (U = 319.5, P = 0.006). In the high irregularity group, gland irregularity correlated with the Schirmer test (r = 0.530, P = 0.001) and corneal fluorescein staining (r = −0.377, P = 0.021). Conclusions: Automated morphological analysis of meibomian gland structure provides additional quantitative and objective information regarding gland morphology. The link between dropout area and gland function is not clear. Assessment of gland irregularity might better predict gland function and its effects on ocular surface and tear film parameters

A Novel Automated Approach for Infrared-Based Assessment of Meibomian Gland Morphology

Purpose: We present and validate a new methodology for analyzing, in an automated and objective fashion, infrared images of the meibomian glands (MG). Methods: The developed algorithm consists of three main steps: selection of the region of interest, detection of MG, and analysis of MG morphometric parameters and dropout area (DOA). Additionally, a new approach to quantify the irregularity of MG is introduced. We recruited 149 adults from a general population. Infrared meibography, using Keratograph 5M, was performed. Images were assessed and graded subjectively (Meiboscore) by two experienced clinicians and objectively with the proposed automated method. Results: The correlation of subjective DOA assessment between the two clinicians was poor and the average percentage of DOA estimated objectively for each Meiboscore group did not lie within their limits. The objective assessment showed lower variability of meibography grading than that obtained subjectively. Additionally, a new grading scale of MG DOA that reduces intraclass variation is proposed. Reported values of MG length and width were inversely proportional to the DOA. Gland irregularity was objectively quantified. Conclusions: The proposed automatic and objective method provides accurate estimates of the DOA as well as additional morphologic parameters that could add valuable information in MG dysfunction understanding and diagnosis. Translational Relevance: This approach highlights the shortcomings of currently used subjective methods, and provides the clinicians with an objective, quantitative and less variable alternative for assessing MG in a noninvasive and automated fashion. It provides a viable alternative to more time-consuming subjective methods

Randomized crossover trial of silicone hydrogel contact lenses

Purpose: The aim of the current study is to assess, using new technologies, the interaction of four monthly silicone hydrogel contact lenses on the ocular surface and the comfort over 15 days of use. Methods: Prospective cross-over, randomized and double-masked study including four materials (lotrafilcon-B, samfilcon-A , comfilcon-A and filcom-V3). Clinical examination was performed in the following order: tear meniscus height, first break-up of the tear film, the average time of all tear film breakup incidents, bulbar redness, limbal redness (Keratograph 5M ,Oculus, Germany); central corneal thickness (Pentacam, Oculus, Germany), thermography values (FLIR A325; FLIR Systems Inc., USA), and slit-lamp evaluations, including ocular surface staining. Finally, subjective comfort was obtained from Contact Lens Dry Eye Questionnaire-8. Results: The impact of contact lens wear on the ocular surface didn’t show statistically significant changes over time except for corneal and conjunctival staining grades on day 15 compared to day 1 for the comfilcon A group (P = .003 and P = .01, respectively). Contact lens stability and impact on the ocular surface during contact lens wear didn’t show statistically significant changes over time except in the case of the comfilcon A material with respect to the irritation item (P = .01). Conclusions: These results suggest that the impact of monthly silicone hydrogel contact lens materials on the ocular surface after and during contact lens wear, contact lens stability over time, and subjective comfort did not reveal any significant changes over 15 days of use for any of the materials

The influence of meibomian gland loss on ocular surface clinical parameters

Purpose: To assess the relationship between the meibomian gland loss (MGL) and relevant ocular surface clinical parameters as well as the influence of age in this relationship. Methods: A total of 161 participants (mean age; 42±17 years) were enrolled in this study. Infrared meibography was performed using Keratograph 5M (K5M; Oculus GmbH, Wetzlar). Participants were divided into five groups according to total meiboscore and the ocular surface parameters of each MGL group were studied. In addition, the relationship between MGL and the ocular surface parameters was established including age as covariant. Results: Both eyelids were taken into account since no association between the MGL from upper and lower eyelid was found (k value=0.2; p=0.3) despite they were significantly correlated (r= 0.3; p<0.001). No statistically significant differences were found in symptomatology among different MGL groups. Statistically significant differences were found among MGL groups in tear osmolarity (p=0.02), bulbar redness (p=0.04), corneal and conjunctival staining (p=0.01 and p=0.004, respectively). Despite this, only corneal staining showed a significant correlation with MGL when age was covariant (r=0.2; p=0.04). Conclusions: MGL higher than 50% seems to be accompanied by signs on the ocular surface. Furthermore, age demonstrated to be a relevant factor when assessing MGL. For this reason, future studies should compare age-matched groups in order to know the contribution of the MGL on the ocular surface and establish valid cut-off values for dry eye diagnosis

Pharmaceuticals and personal care products (PPCPs) in the environment and their removal from wastewater through constructed wetlands

Pharmaceuticals and personal care products are emerging organic contaminants that are continuously introduced into the environment due to their regular and widespread consumption by human beings. Their sources and fate in the aquatic environment are multiple and depend on the particular compound. Conventional wastewater treatment plants constitute the major source of these contaminants in the environment due to their incomplete removal by unspecific treatment methods. While advanced treatment technologies are available to treat these substances, their use is oftentimes not economically justified under the current concept of wastewater treatment. In this context, constructed wetlands represent an appropriate low-cost, energy-efficient, and easy-to-operate technology to treat wastewater, which are able to achieve a very high removal of these substances due to the vast number of biotic and abiotic processes that occur within these units, especially when different wetland types are used.Postprint (published version