Search results for "Tear meniscus"
showing 8 items of 8 documents
Comparison of the influence of corneo-scleral and scleral lenses on ocular surface and tear film metrics in a presbyopic population
2018
PURPOSE: To assess and compare the effect of the corneo-scleral lenses (C-ScL) and scleral lenses (ScL) on tear film parameters and central corneal thickness (CCT) in healthy presbyopic subjects. METHODS: Thirty subjects wore two contact lenses (CLs), randomly assigned, of neutral power, but of different diameters, 12.7mm (C-ScL) and 18mm (ScL) and being equal in the others parameters: material (HS100) and centre thickness (0.29mm). At baseline, 20min after insertion and at 8h, the tear meniscus area (TMA) and CCT was measured (with optical coherence tomography) as well as tear osmolarity. RESULTS: TMA revealed statistical differences for both lenses at 20min (p<0.001), and also at 8h (p=0.…
Impact of contact lens material and design on the ocular surface.
2018
BACKGROUND: To evaluate the impact on the ocular surface of a daily disposable hydrogel contact lens with high water content compared with two silicone hydrogel daily disposable lenses of lower water content. METHODS: The hydrogel lens assessed was made from nesofilcon A and the silicone hydrogel lenses were made of delefilcon A and stenfilcon A. Contact lens thickness was measured to assess material stability during daily wear, and ocular surface parameters such as tear film osmolarity, tear meniscus area and central corneal thickness were also assessed. Optical quality was analysed for all cases by means of wavefront aberrometry. RESULTS: The nesofilcon A was shown to be the thinnest lens…
Evaluating tear clearance rate with optical coherence tomography
2017
Purpose: To assess the early-phase of tear clearance rate (TCR) with anterior segment optical coherence tomography (OCT) and to determine the association between TCR and other clinical measures of the tear film in a group of young subjects with different levels of tear film quality. Methods: TCR was classified as the percentage decrease of the inferior tear meniscus height 30s after instillation of 5uL 0.9% saline solution. Fifty subjects (32F and 18M) aged (mean +/- standard deviation) 25.5 +/- 4.3 years volunteered for the study. It consisted of a review of medical history, Ocular Surface Disease Index (OSDI) questionnaire, tear film osmolarity measurements, slit lamp examination and TCR …
Valoración de los parámetros geométricos del menisco lagrimal mediante tomografía de coherencia óptica, y su aplicación en el diagnóstico diferencial…
2022
La unidad funcional lagrimal es un sistema integral formado por las glándulas lagrimales y de Meibomio, la superficie ocular (córnea y conjuntiva) y los párpados, así como los nervios sensoriales y motores que los conectan. El mecanismo homeostático de la unidad funcional lagrimal regula la secreción y distribución de la lágrima en respuesta a las señales de la superficie ocular, siendo uno de sus principales objetivos el mantenimiento de una adecuada película lagrimal precorneal. La película lagrimal está formada por dos capas, una capa lipídica externa y un gel muco-acuoso interno en contacto con el glicocálix del epitelio corneal. De vital importancia para su formación es el menisco lagr…
Response of the aging eye to first day of modern material contact lens wear
2018
Objectives: To investigate the ocular surface of an aged population wearing a daily disposable contact lens over their first day of wear. Methods: Forty eyes from forty presbyopic subjects were fitted a daily CL (Delefilcon A). Tear osmolarity, tear meniscus area (TMA) and ocular surface aberrations (total higher order root means square (RMS)) were assessed at baseline (t0), at 20 minutes (t1) and after 8 hours (t2) of wear. Fluorescein corneal and conjunctival staining and tear break up time (TBUT) were performed at t0 and t2. Results: No statistically significant changes were found between t0, t1 and t2 for TMA, and between t0 and t2 for fluorescein corneal and conjunctival staining. TBUT…
OCT for Assessing Artificial Tears Effectiveness in Contact Lens Wearers
2011
PURPOSE: To apply a commercially available high-resolution spectral domain optical coherence tomographer (SOCT) to assess the change in tear volume after application of a new artificial tears formulation specifically developed for contact lens (CL) users. METHODS: Twenty OD from young healthy CL wearers (mean age, 24.7 ± 3.5 years) with refractive errors ranging from -0.75 to -2.50 D (mean, -1.56 ± 0.69 D) were examined. All subjects were fitted with Focus Dailies CL (Ciba Vision), and two drops of Blink Contacts (AMO), lubricating formulation specifically developed for CL wearers, were instilled after baseline measures. Tear meniscus volume (TMV) was measured immediately after and 1 min, 1…
Diagnostic Capability of a New Objective Method to Assess Meibomian Gland Visibility
2021
SIGNIFICANCE The diagnosis of dry eye disease and meibomian gland dysfunction (MGD) is challenging. Measuring meibomian gland visibility may provide an additional objective method to diagnose MGD. PURPOSE This study aimed to evaluate the ability of new metrics to better diagnose MGD, based on measuring meibomian gland visibility. METHODS One hundred twelve healthy volunteers (age, 48.3 ± 27.5 years) were enrolled in this study. Ocular surface parameters were measured using the Oculus Keratograph 5M (Oculus GmbH, Wetzlar). Subjects were classified according to the presence or absence of MGD. New metrics based on the visibility of the meibomian glands were calculated and later compared betwee…
Assessment of corneal thickness and tear meniscus during contact-lens wear
2014
To assess the effect of seven different daily disposable contact lenses upon corneal thickness, as well as upon tear meniscus volume, by using optical coherence tomography (OCT).Thirty-four young healthy subjects wore seven different types of daily disposable soft contact lenses, each for a period of 12h: Delefilcon A, Nelfilcon A, Omafilcon A, Filcon II3, Narafilcon A, Etafilcon A and Hilafilcon B. Central and mid-peripheral corneal thickness and lower tear meniscus volume (TMV) were measured using an OCT device during contact-lens wear at 4-h intervals throughout a 12-h period. Measurements were also recorded without any contact lenses being worn during a day.In the no-lens scenario a sma…