Langis Michaud

Université de Montréal | UdeM · School of Optometry

A huge body of literature supports the concept, but many ODs struggle to implement various interventions. Here are lessons learned from the research that can help you.

Objectives To evaluate the retinal response to myopic defocus after the wear of soft multifocal contact lenses with high addition through electroretinography. Methods Twenty-seven participants meeting inclusion criteria were enrolled. Tropicamide 1% drops (2) were instilled. Participants were then fitted with three different contact lenses: a sing...

OBJECTIVE: To evaluate the effect of the orthokeratology (OK) lens design, used in the Montreal Experience cohort, on corneal treatment zone characteristics and their relationship to the pupil. METHODS: This retrospective study follows previously published work and refers to the analysis of 4 different OK lenses. Tangential topography maps were obt...

To determine if the magnitude of angle kappa (𝝹) or angle alpha (𝛼) influence clinical outcomes, uncorrected visual acuity or patient-reported satisfaction in patients implanted with multifocal or EFOD IOLS

An in-depth look at customizing orthokeratology approaches.

Purpose To present the process that led to the creation of the French Canadian translated version of the Contact Lens Dry Eye Questionnaire-8 (which allows for an assessment of symptoms while wearing soft contact lenses) as well as the validation data of the f-CLDEQ-8. Methods The CLDEQ-8 went through the process of reverse translation, which was...

32 NAVIGATING LENS CHOICE I t Õs diffi cult not to observe that the recent industry focus on scleral contact lenses-whether pertaining to clinical education, research and development, and/ or practice management-has defi nitely outpaced the attention paid to corneal gas permeable lenses. While we enthusiastically embrace the continuing developments...

Purpose: This study aims to evaluate potential causes of FDT visual field loss in a selected group of Fabry subjects. Patients and methods: This is a pilot observational study. Subjects were assessed during 2 visits. The following tests were performed: visual acuity, tonometry, optical coherence tomography (OCT) optic nerve scan, frequency doubl...

The purpose of this study was to survey a population in the Montreal area (Quebec, Canada) for its opinion concerning the importance of making children's first eye examinations legally mandatory before the children start school.

CONTEXT: Authors have refined myopia control strategies (MCS) from their experience treating more than 800 children who were followed at the Montreal School of Optometry Clinic (CUV). They developed a treatment algorithm known as the Montreal Experience (ME). Contrary to many other MCS, treatment modalities are selected after careful evaluation of...

Orthokeratology (ortho-k) is the process of deliberately reshaping the anterior cornea by utilising specialty contact lenses to temporarily and reversibly reduce refractive error after lens removal. Modern ortho-k utilises reverse geometry lens designs, made with highly oxygen permeable rigid materials, worn overnight to reshape the anterior cornea...

Scleral lenses were the first type of contact lens, developed in the late nineteenth century to restore vision and protect the ocular surface. With the advent of rigid corneal lenses in the middle of the twentieth century and soft lenses in the 1970’s, the use of scleral lenses diminished; in recent times there has been a resurgence in their use dr...

PurposeThis study aims to determine if lens or tear fluid reservoir thicknesses (LT/FRT) may influence the presence of residual astigmatism and participant’s visual acuity. Methods The study was a randomized, non-dispensing, prospective study. Empirically and randomly chosen participants were fitted with 4 combinations (350 and 250 um LT fitted wit...

Objective: The purpose of this study was to evaluate the change in Bruch membrane opening minimum rim width (BMO-MRW) during scleral lens (SL) wear. Methods: Twenty young white subjects were enrolled (10 women and 10 men); preliminary evaluation consisted of serial measurements of intraocular pressure (IOP) using a dynamic noncontact tonometer (...

Vulgarisation de la pathophysiologie, classification et traitement du glaucome

Myopia management update

Discussion about residual astigmatism with scelral lenses

This article defines a pathway for integrating myopia management into practice for practitioners who want to join the resistance against myopia. Here, the term “management” refers to managing both refractive error and axial length.

Nowadays, practitioners are playing a more active role in comanaging patients after ocular surgery. This involves optimizing refractive results and, less frequently, restoring visual acuity to irregular ocular surfaces that may have been altered by infection or trauma (including the surgery itself). Specialty contact lenses are one solution, offeri...

Applying the theory of the 4th phase of water to scleral lens fogging issues

Significance: In the bleb phenomenon, some endothelial cells transiently lose their specular reflection. This has been reported during contact lens wear and goggle-induced hypoxia or hypercapnia. Purpose: The purposes of this study were to determine whether blebs appear after scleral lens wear and if their appearance is influenced by lens cleara...

Purpose: In absence of scleral lens standards, this article aims to provide an official definition of terms related to scleral lens fitting and manufacturing, in order to make more uniform the use of appropriate terms when describing, writing or lecturing about scelral lenses. Adoption of a common terminology may also favor more fruitful exchanges...

Purpose This study aims to assess the evolution of ocular manifestations in a cohort of Fabry patients. Methods This is a prospective observational study conducted from 2013 to 2017 (5 consecutive exams). All subjects underwent a comprehensive ocular examination including oriented case history, refraction, corneal topography, biomechanical corneal...

Background and Objective To determine the relationships between corneal and scleral elevation topography in subjects with corneal ectasias and normal corneas. Material and Methods This is a multi-site retrospective study. Ocular surface topography (sMap3D, Precision Ocular Metrology, US) was collected on 115 eyes with prolate cornea profile (Group...

Cette étude a pour but premier d’établir les caractéristiques oculaires individuelles d’une population diagnostiquée de la maladie de Fabry et d’en suivre l’évolution sur une période de 5 ans. Le second but de l’étude est d’établir la fréquence des atteintes oculaires en fonction du sexe des patients atteints, de leur degré de gravité de la maladie...

Best practice clinical guidelines for myopia control involve an understanding of the epidemiology of myopia, risk factors, visual environment interventions, and optical and pharmacologic treatments, as well as skills to translate the risks and benefits of a given myopia control treatment into lay language for both the patient and their parent or ca...

Purpose This study aims to assess the evolution of ocular manifestations in a cohort of Fabry patients. METHODS This is a prospective observational study conducted from 2013 to 2017 (5 consecutive exams). All subjects underwent a comprehensive ocular examination including oriented case history, refraction, corneal topography, biomechanical corneal...

Purpose: This study aims to assess the evolution of ocular manifestations in a cohort of Fabry patients. Methods: This is a prospective observational study conducted from 2013 to 2017 (5 consecutive exams). All subjects underwent a comprehensive ocular examination including oriented case history, refraction, corneal topography, biomechanical cornea...

En 2014, le Groupe de consensus canadien sur la sécheresse oculaire a publié un document intitulé Dépistage, diagnostic et prise en charge de la sécher-esse oculaire : guide pratique à l’intention des optométristes canadiens. Ce guide pratique ne traitait pas des répercussions de la sécheresse oculaire chez les personnes en voie de subir une interv...

Purpose: To evaluate the variation of intra-ocular pressure during scleral lens wear, and the influence of the lens diameter on the results. Methods: This is a prospective, randomized study performed on Caucasian subjects (16 F; 5 M), aged 24.7 + 4.1 y.o. A diurnal variation pattern (IOPg) was established, then, transpalpebral IOP (IOPt) was tak...

PURPOSE: This article aims to report a new clinical finding associated with the wear of scleral lenses. METHODS: Non-contact lens wearer subjects were recruited and fitted with large diameter (18 mm) scleral lenses. Lens was randomly filled with non preserved saline or non preserved carboxymethylcellulose-based artificial tears (Refresh Celluvisc,...

Significance: The present study with small-diameter scleral lenses (SLs) revealed that post-lens tear thickness (PoLTT) was significantly associated with post-lens tear mixing, but not with central corneal edema, after short-term SL wear. Purpose: The aim of this study was to investigate the influence of SL tear clearance (PoLTT) on central corn...

In 2014, the Canadian Dry Eye Disease Consensus Panel published Guidelines for screening, diagnosis and management of dry eye diseases (DED). These did not address the implications of DED for individuals who are being considered for or have recently undergone ocular surgery. DED is common in certain surgical cohorts, and the perisurgical setting po...

Purpose: This study aims to analyze two commercial orthokeratology lens designs and compare their optical effects at the corneal level. Methods: This is a retrospective study on subjects seeking an orthokeratology fitting for myopia management at the Université de Montréal clinic between January 2013 and August 2015. Group A included the first 6...

Background and Objectives: Objective was to examine new findings regarding conjunctival/scleral shape mapped with a novel wide field elevation topography device and software, to propose a new classification system for scleral shape. Methods: The Scleral Shape Study Group (SSSG) collaborated on this research. Data was collected from 152 eyes of pros...

This lecture aims to review the current ways to clinically assess the conjunctival profile related to scleral lens fitting. It détails the challenge we face and raises many questions that remain unanswered for the moment. Optimization of scleral lens fitting is necessary and will imply a quadrant specific approach.

The present disclosure relates to a method for differentiating a blood absorption contribution and an absorption contribution by other optical structures of a patient’s eye to a full spectral retinal reflectometry absorption function, comprising: performing reflectometry absorption measurement on the vessels of the patient’s retina at a first numbe...

Classrooms environment may be a very detrimental contributor for myopia increase. This lecture addresses lightning condition and other elements to improve classroom environments.

Technology and smart phones are challenging for the eyes. We are animals who adapt to such challenges. This lecture demonstrates the impact of modern technology on myopia development and suggests some ways to ease this adaptation

Authors explore several common issues in scleral lenses and explain how to troubleshoot them

Co-author with Dr Christine Sindt. this lecture évaluâtes when a smaller scleral lens is needed and when a larger one may be preferred. Risk and benefits are given for each type of scleral lenses

this lecture explores different clinical applications for slcerals, hybrid, small gas permeable lenses and customized soft lenses. At the end, with these 4 types of lenses, any practitioner may answer to any patient's needs.

This lecture describes what, in theory, a soft lens would have to offer to match OK outcomes. It discusses the results obtained with several soft lens designs available.

Conférence portant sur les requis visuels en milieu scolaire et l’impact de l’environnement des classes, au Québec, sur la vision. This lecture aims to describe visual requirements for children and students and the impact of the class environment on vision, which includes the development of myopia

Purpose: This study aims to evaluate the settling of a scleral lens and if this process is influenced by the nature of the fluid layer. Methods: A prospective, non-randomized control study was performed using an 18mm scleral lens. They were fitted with a central clearance of 400 um at insertion. One eye was randomly assigned to be fitted with a no...

Purpose: This study aims to evaluate the settling of a scleral lens and if this process is influenced by the nature of the fluid layer. Methods: A prospective, non-randomized control study was performed using an 18 mm scleral lens. They were fitted with a central clearance of 400 um at insertion. One eye was randomly assigned to be fitted with a...

This lecture explores benefits and risks of fitting scleral lenses on a normal population

This lecture explores the causes explaining why myopia is becoming epidemic and how to adress this issue.

This lecture explores and compare several myopia control strategy. It defines when OK is not the best approach and when other stratégies should be put in place.

This lecture présents and compares different techniques to evaluate and assess ocular surface. It discusses how to apply this technologies to lens design (soft and sclerals)

Purpose: To evaluate the relative partial pressure in oxygen (pO2) at the corneal surface under Boston XO2 scleral lenses (SL) fitted with targeted clearances of 200 and 400 μm (SL200 and SL400). Methods: During this prospective study, the right eyes of eight normal subjects were fitted with SL200 and SL400. Clearance, validated after 5 minutes...

Purpose: This study aims to address the clinical performance of a large diameter rigid gas permeable lens (LRGP) in a group of subjects with low-to-moderate (0.75-2.75 D) refractive astigmatism. An additional goal was to determine whether soft toric or LRGP contact lenses performed better objectively in the correction of astigmatism and to determi...

I. Case History • Patient demographics : CG, 54 YO, Caucasian Female • Chief complaint: Contact lens intolerance since the last 6 months • Ocular, medical history: Fitted in gas-permeable contact lenses > 30 years ago. Always been comfortable with no issue about lenses or ocular health . Her last pair of contact lenses was purchased 14 months ago...

Course Description: Technological advancements in lenses designs and manufacturing availabilities have led to wider clinical utilizations of both hybrid and scleral contact lenses. Great patient successes have been observed in both irregular and regular corneas. This lecture will illustrate the optimal usage and selection algorithm for these new le...

It is difficult to fully compensate presbyopia and astigmatism in contact lenses. This case report opens the discussion on the optimal options to select for a patient showing moderate refractive astigmatism, myopia and presbyopia. Hybrid lenses and sclerals are considered the best options. Sclerals were selected as a final choice considering a limi...

This study aims to assess post-lens tear dynamics with scleral lenses fit with various clearances by measuring the time required for fluorescence to travel from the pre-lens (PrLTF) to post-lens tear film (PoLTF) near the lens periphery using the out-in method (OIT). Results show that OIT is a valid predictive method, that with optimal clearance OI...

This study aims to evaluate the rate of success in the fitting of mini-scleral lenses during 1 year, evaluate the complication rate associated with the prescription of mini-scleral lenses, determine the causes for fitting failures, determine the number of visits required to complete a successful fit with mini-sclerals and compare data between norma...

This study aims to evaluate relative pO2 at the corneal surface under scleral rigid gas permeable lenses of different clearances. Results indicate that higher clearance in scleral lenses is associated with chronic edematous response from the central cornea. This raises the importance of evaluating the risk/benefits ratio before fitting patients, es...

It's not rare occurrence in our offices when a patient comes in with the first symptoms of presbyopia. Those that have had refractive surgery present some fairly common challenges. The following 2 cases illustrate different approaches in correcting their presbyopia, particularly with contact lenses.

Description of a 4 steps algorithm to select the best myopia control strategy

Objective: Amplify the absorbance signal related to the lysozyme extracted from contact lenses as measured by high-performance liquid chromatography (HPLC); examine the purity of lysozyme and how much thermal denaturation affects its elution profile. Methods: In trial chromatographic runs during which contact lens extracts had been injected into th...

Purpose: This study aimed to compare two daily disposable lenses to reduce lens-induced discomfort (CLD) among different populations of symptomatic wearers. Methods: This was a multicenter, crossover, study. Subjects were contact lens wearers reporting CLD. Subjects (76) were randomly assigned to wear Nelfilcon A (NF) then Delefilcon A (DF)- gro...