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Home / Archives for Lisa Dockray

TFOS DEWS II – Definition and Classification Report

February 16, 2023 by Lisa Dockray

Jennifer P. Craig, MCOptom, PhD, Kelly K. Nichols, OD, PhD, Esen K. Akpek, MD, Barbara Caffery, OD, PhD, Harminder S. Dua, MD, PhD, Choun-Ki Joo, MD, PhD, Zuguo Liu, MD, PhD, J. Daniel Nelson, MD, Jason J. Nichols, OD, PhD, Kazuo Tsubota, MD, PhD, Fiona Stapleton, MCOptom, PhD

ABSTRACT:

The goals of the TFOS DEWS II Definition and Classification Subcommittee were to create an evidence based definition and a contemporary classification system for dry eye disease (DED).

The new definition recognizes the multifactorial nature of dry eye as a disease where loss of homeostasis of the tear film is the central pathophysiological concept. Ocular symptoms, as a broader term that encompasses reportsof discomfort or visual disturbance, feature in the definition and the key etiologies of tear film instability, hyperosmolarity, and ocular surface inflammation and damage were determined to be important for inclusion in the definition. In the light of new data, neurosensory abnormalities were also included in the definition for the first time.

In the classification of DED, recent evidence supports a scheme based on the pathophysiology where aqueous deficient and evaporative dry eye exist as a continuum, such that elements of each are considered in diagnosis and management. Central to the scheme is a positive diagnosis of DED with signs and symptoms, and this is directed towards management to restore homeostasis. The scheme also allows consideration of various related manifestations, such as non-obvious disease involving ocular surface signs without related symptoms, including neurotrophic conditions where dysfunctional sensation exists, and cases where symptoms exist without demonstrable ocular surface signs, including neuropathic pain.

This approach is not intended to override clinical assessment and judgment but should prove helpful in guiding clinical management and research.

(J.P. Craig et al. / The Ocular Surface 15 (2017) 276-283)

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Filed Under: Clinicals

The Utility of Normal Tear Osmolarity Results

February 16, 2023 by Lisa Dockray

By: Christopher E. Starr, MD

Hyperosmolarity is a well-established fundamental characteristic of dry eye disease (DED).1

When patients have dry eye symptoms, osmolarity testing is a logical step to confirm the diagnosis, but what does it mean when the tear osmolarity test is normal in a patient with symptoms suggesting DED?

In the early days of point-of-care tear osmolarity testing, many practitioners faced with this diagnostic dilemma assumed the test was inaccurate because it went against their clinical judgment. When osmolarity testing disagreed, our early reaction was often that the machine must be wrong. We now know otherwise.

Just as tear osmolarity can help us diagnose DED, it can also help us know when to pause and look for an alternative diagnosis. My colleagues and I conducted a study exploring how osmolarity testing can help make alternate diagnoses in symptomatic patients.

Take-home message

Patient symptoms are not an effective method to diagnose dry eye as they often overlap with other pathologies. Tear osmolarity results provide clues for alternative diagnoses.

(Ophthalmology Times, March 15, 2017)

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Filed Under: Articles

Tear Film Osmolarity: Determination of a Referent for Dry Eye Diagnosis

February 16, 2023 by Lisa Dockray

Alan Tomlinson, Santosh Khanal, Kanna Ramaesh, Charles Diaper, and Angus McFadyen

● PURPOSE: To determine new referents, or cutoff levels for tear film hyperosmolarity in the diagnosis of keratoconjunctivitis sicca (KCS) and to assess their effectiveness in independent patient groups.

● METHOD: A meta-analysis was performed on published data for tear osmolarity in samples of normal eyes and various subtypes of dry eye, and pooled estimates of the mean and standard deviations for normal and (all) dry eye subjects were determined. Diagnostic referents were derived from the intercept between the distributions of osmolarity in the two samples and from receiver operator characteristic (ROC) curves. This referent was tested for effectiveness of diagnosis in independent groups with normal and dry eyes.

● RESULTS: An osmolarity referent of 315.6 mOsmol/L was derived from the intercept of the distribution curves, and 316 mOsmol/L from the ROC curve. When applied to independent groups of normal and dry eye subjects a value of 316 mOsmol/L was found to yield sensitivity of 59%, specificity of 94%, and an overall predictive accuracy of 89% for the diagnosis of dry eye syndrome.

● CONCLUSIONS: Tear hyperosmolarity, defined by a referent of 316 mOsmol/L, was superior in overall accuracy to any other single test for dry eye diagnosis (Lactoplate, Schirmer test, and Rose Bengal staining), even when the other test measures were applied to a diagnosis within the sample groups from which they were derived. For overall accuracy in the diagnosis of dry eye, the osmolarity test was found to be comparable with the results of combined (in parallel or series) tests.

(Invest Ophthalmol Vis Sci. 2006;47:4309–4315) DOI:10.1167/iovs.05-1504)

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Filed Under: Clinicals

Tear Osmolarity in the Diagnosis and Management of Dry Eye Disease

February 16, 2023 by Lisa Dockray

MICHAEL A. LEMP, ANTHONY J. BRON, CHRISTOPHE BAUDOUIN, JOSÉ M. BENÍTEZ DEL CASTILLO, DAVID GEFFEN, JOE TAUBER, GARY N. FOULKS, JAY S. PEPOSE, AND BENJAMIN D. SULLIVAN

● PURPOSE: To evaluate the use of tear osmolarity in the diagnosis of dry eye disease.

● DESIGN: A prospective, observational case series to determine the clinical usefulness of tear osmolarity and commonly used objective tests to diagnose dry eye disease.

● METHODS: A multicenter, 10-site study consisting of 314 consecutive subjects between 18 and 82 years of age. Bilateral tear osmolarity, tear film break-up time (TBUT), corneal staining, conjunctival staining, Schirmer test, and meibomian gland grading were performed. Diagnostic performance was measured against a composite index of objective measurements that classified subjects as having normal, mild or moderate, or severe dry eye. The main outcome measures were sensitivity, specificity, area under the receiver operating characteristic curve, and intereye variability.

● RESULTS: Of the 6 tests, tear osmolarity was found to have superior diagnostic performance. The most sensitive threshold between normal and mild or moderate subjects was found to be 308 mOsms/L, whereas the most specific was found at 315 mOsms/L. At a cutoff of 312 mOsms/L, tear hyperosmolarity exhibited 73% sensitivity and 92% specificity. By contrast, the other common tests exhibited either poor sensitivity (corneal staining, 54%; conjunctival staining, 60%; meibomian gland grading, 61%) or poor specificity (tear film break-up time, 45%; Schirmer test, 51%). Tear osmolarity also had the highest area under the receiver operating characteristic curve (0.89). Intereye differences in osmolarity were found to correlate with increasing disease severity (r2 = 0.32).

● CONCLUSIONS: Tear osmolarity is the best single metric both to diagnose and classify dry eye disease. Intereye variability is a characteristic of dry eye not seen in normal subjects.

(Am J Ophthalmol 2011;151:792–798. © 2011 by Elsevier Inc. All rights reserved.)

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Filed Under: Clinicals

Analytic and clinical performance of two compact cholesterol-testing devices

February 16, 2023 by Lisa Dockray

Volles DF, McKenney JM, Miller WG, Ruffen D, Zhang D.

ABSTRACT:

Several relatively inexpensive compact analyzers for measuring cholesterol are available for use outside of the clinical laboratory. We evaluated the analytic and clinical performance of total cholesterol assayed with the AccuMeter (ChemTrak) and the LDX (Cholestech). Accuracy of both devices was evaluated by collecting capillary and venous whole blood from 100 subjects and assaying for total cholesterol.

Results were compared with the Centers for Disease Control standardized reference laboratory method. Mean percent bias, mean absolute percent bias, and percentage of subjects with total error above +/- 8.9% were calculated and results were compared with recommendations from National Cholesterol Education Program (NCEP) for total cholesterol measurements. Precision was evaluated by assay of three pooled serum samples with both devices in duplicate in two runs/day for 20 days. The CV for each serum pool for each device was calculated and compared with NCEP recommendations for precision for total cholesterol measurements. Results with the two devices were compared. The total cholesterol mean percent bias for capillary samples was 2.1% for the LDX and -1.0% for the AccuMeter (p<0.01), and for venous samples 1.6 and -2.0%, respectively (p<0.001). The mean absolute percent bias for capillary samples was 5.4 and 5.2%, respectively (p=0.29), and for venous samples was 5.0 and 5.7% (p=0.79). Each device had an excessive number (12-22%) of individual results that exceeded NCEP recommended total error for a single cholesterol measurement (+/- 8.9%).

In the precision analysis the average CV from all three serum pools was 4.0% and 5.3% for the LDX and AccuMeter, respectively (p<0.05). Thus both devices failed to meet the NCEP recommendation for precision of 3% CV. They both provided total cholesterol results that correctly classified individual patients into appropriate risk groups 95% of the time or better if values within +/- 8.9% of NCEP cut points for risk classification were ignored. Both devices met the NCEP +/- 3% requirement for total cholesterol mean percent bias but did not meet the +/- 3% requirement for CV as a measure of precision. Because of the variability in results, both devices had excessive numbers of individual subjects with total cholesterol results greater than the recommended total error limit of +/- 8.9% difference from the standardized method.

Despite variability in some individual results, the rate of clinical misclassifications for coronary heart disease risk was relatively low for both devices if results near the NCEP cut points were repeated.

(Pharmacotherapy. 1998 Jan-Feb;18(1):184-92.)

Filed Under: Clinicals

Variability among five over-the-counter blood glucose monitors

February 16, 2023 by Lisa Dockray

Kimberly MM, Vesper HW, Caudill SP, Ethridge SF, Archibold E, Porter KH, Myers GL.

ABSTRACT:

● Background: The American Diabetes Association recommends that people with diabetes use self-monitoring to control their blood glucose concentration. To assess the need for standardization, we evaluated the variability among 5 of the most common monitors: MediSense Precision Xtra, Ascencia Dex, Prestige Smart System, OneTouch Ultra, and Accu-Chek Advantage.

● Methods: We took steps to minimize preanalytical variation. We also eliminated user variability by using one trained operator to collect samples and perform all testing. Each monitor was used twice with each participant; one test was performed using an aged strip and the other using a fresh strip. We compared monitors using a separate ANOVA for each concentration range and strip lot.

● Results: The total CVs and the within-strip lot CVs were not statistically different among monitors, ranging from 3.1% to 11.3% and from 2.1% to 8.5%, respectively. There were statistically significant differences among monitors for among-strip lot CVs, which ranged from nearly 0% to 7.5%. The degree of significance increased as the concentration range increased [3.9-5.5 mmol/l: p<0.05; 5.6-7.7 mmol/l: p =0.003; 7.8-11.1 mmol/l: p < 0.001]. The average percent difference between monitor pairs was statistically significant (p < 0.05) in more than half of the paired comparisons, with significant differences ranging from 5.7% to 32.0%.

● Conclusions: Monitor results can vary significantly so that agreement among them is poor. Standardization is necessary to minimize variability and to improve patient care.

(Clin Chim Acta. 2006 Feb;364(1-2):292-7. Epub 2005 Sep 6.)

Filed Under: Clinicals

Effect of tear osmolarity on repeatability of keratometry for cataract surgery planning

February 15, 2023 by Lisa Dockray

Alice T. Epitropoulos, MD, Cynthia Matossian, MD, Gregg J. Berdy, MD,
Ranjan P. Malhotra, MD, Richard Potvin, OD

● PURPOSE: To evaluate the effects of tear osmolarity on the repeatability of keratometry (K) measurements in patients presenting for cataract surgery.

● SETTING: Three clinical practices.

● DESIGN: Observational prospective nonrandomized study.

● METHODS: Subjects were prospectively recruited based on tear osmolarity (Tearlab Osmolarity System); that is, osmolarity more than 316 mOsm/L in at least 1 eye (hyperosmolar) and osmolarity less than 308 mOsm/L in both eyes (normal). The baseline K value was measured, and a second measurement was taken on the same instrument (IOLMaster) within 3 weeks of the first. Variability in average K, calculated corneal astigmatism using vector analysis, and intraocular lens (IOL) sphere power calculations were compared between groups.

● RESULTS: The hyperosmolar group (50 subjects) had a statistically significantly higher variability in the average K reading (PZ.05) than the normal group (25 subjects) and a statistically significantly higher percentage of eyes with a 1.0 diopter (D) or greater difference in the measured corneal astigmatism (PZ.02). A statistically significantly higher percentage of eyes in the hyperosmolar group had an IOL power difference of more than 0.5 D (P Z .02). No statistically significant differences were present when the subjects were grouped by self-reported dry eye.

● CONCLUSIONS: Significantly more variability in average K and anterior corneal astigmatism was observed in the hyperosmolar group, with significant resultant differences in IOL power calculations. Variability was not significantly different when subjects were grouped by self-reported dry eye. Measurement of tear osmolarity at the time of cataract surgery planning can effectively identify patients with a higher likelihood of high unexpected refractive error resulting from inaccurate keratometry.

(J Cataract Refract Surg 2015; 41:1672–1677 © 2015 ASCRS and ESCRS)

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Filed Under: Articles

Cornea and Sclera

February 15, 2023 by Lisa Dockray

Duane’s Foundations of Clinical Ophthalmology – Volume 2
Physiology of the Eye and Visual System
Daniel G. Dawson, Mitchell A. Watsky, Dayle H. Geroski, Henry F. Edelhauser



Please click below to view Chapter 4 detailing the cornea and sclera of the vast reference that is Duane’s Foundations of Clinical Ophthalmology.

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Filed Under: Articles

A Game-Changing Approach to Help Overcome Contact Lens Dropout

February 15, 2023 by Lisa Dockray

By: Paul Karpecki, OD, Ian Benjamin Gaddie, OD, David Geffen, OD and John Rumpakis, OD, MBA

Contact lens dropout rates have not changed appreciably in nearly two decades. Although new materials and preservative-free products have helped, neither was the tipping point we hoped for in contact lens practice. What’s more, as clinicians, we now face even greater challenges than we once did. The explosion in digital device use has placed an unprecedented burden on the ocular surface, erecting yet another hurdle to comfort. If there is one thing we have learned about contact lens dropout, it is this: We are less likely than ever to overcome it using traditional strategies. It’s time to start thinking outside the box.

In our clinical experience, and in that of many of our forward-thinking colleagues, the most effective way out of what is otherwise sure to be a downward spiral is to catch as many patients as we can as they come in for their annual exams. In other words, we need to identify which patients are at risk of dropping out prior to first fittings and before refits.

In this three-part series, we will explore how osmolarity testing can be the catalyst for change that the contact lens industry has long sought. This surprisingly simple approach is both practical and profitable.

(Review of Optometry, May 15 2016)

Click here to view the full three-part series

● Part One: A GAME-CHANGING APPROACH TO HELP OVERCOME CONTACT LENS DROPOUT – By: Ian Benjamin Gaddie, OD and Paul Karpecki, OD
● Part Two: FITTING WITH CONFIDENCE – By: David Geffen, OD and Paul Karpecki, OD
● Part Three: THE VALUE PROPOSITION: CLINICAL LAB TESTING IN OPTOMETRIC PRACTICE – By: John Rumpakis, OD, MBA and Paul Karpecki, OD

 

Filed Under: Articles

Clinical Applications of LabAmnioTM
Pearls for success with the latest Amniotic Membrane

February 9, 2023 by Lisa Dockray



Dr. Clara Chan, Dr. Guillermo Rocha and Dr. Johanna Choremis share their experience with LabAmnioTM, the latest innovation in amniotic membrane.

This webinar covers clinical cases and videos to demonstrate the use of LabAmnioTM in treating refractory corneal and conjunctival conditions.

Objectives of the webinar:
  • Amniotic Membrane options including LabAmnioTM dehydrated AM
  • Applications in corneal and conjunctival conditions
  • Clinical case experiences in multiple corneal and conjunctival indications
  • Pearls for surgical success
  • Q&A



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Filed Under: Webinars

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