An Automated Grading and Diagnosis System for Evaluation of Dry Eye Syndrome.

This article describes methods used to determine the severity of Dry Eye Syndrome (DES) based on Oxford Grading Schema (OGS) automatically by developing and applying a decider model. The number of dry punctate dots occurred on corneal surface after corneal fluorescein staining can be used as a diagnostic indicator of DES severity according to OGS; however, grading of DES severity exactly by carefully assessing these dots is a rather difficult task for humans. Taking into account that current methods are also subjectively dependent on the perception of the ophtalmologists coupled with the time and resource intensive requirements, enhanced diagnosis techniques would greatly contribute to clinical assessment of DES. Automated grading system proposed in this study utilizes image processing methods in order to provide more objective and reliable diagnostic results for DES. A total of 70 fluorescein-stained cornea images from 20 patients with mild, moderate, or severe DES (labeled by an ophthalmologist in the Keratoconus Center of Yildirim Beyazit University Ataturk Training and Research Hospital) used as the participants for the study. Correlations between the number of dry punctate dots and DES severity levels were determined. When automatically created scores and clinical scores were compared, the following measures were observed: Pearson's correlation value between the two was 0.981; Lin's Concordance Correlation Coefficients (CCC) was 0.980; and 95% confidence interval limites were 0.963 and 0.989. The automated DES grade was estimated from the regression fit and accordingly the unknown grade is calculated with the following formula: Gpred = 1.3244 log(Ndots) - 0.0612. The study has shown the viability and the utility of a highly successful automated DES diagnostic system based on OGS, which can be developed by working on the fluorescein-stained cornea images. Proper implemention of a computationally savvy and highly accurate classification system, can assist investigators to perform more objective and faster DES diagnoses in real-world scenerios.

Consensus on recording of gas permeable contact lens fit.

PURPOSE: To develop a new schematic scheme for efficiently recording the key parameters of gas permeable contact lens (GP) fits based on current consensus. METHODS: Over 100 established GP fitters and educators met to discuss the parameters proposed in educational material for evaluating GP fit and concluded on the key parameters that should be recorded. The accuracy and variability of evaluating the fluorescein pattern of GP fit was determined by having 35 experienced contact lens practitioners from across the world, grading 5 images of a range of fits and the topographer simulation of the same fits, in random, order using the proposed scheme. The accuracy of the grading was compared to objective image analysis of the fluorescein intensity of the same images. RESULTS: The key information to record to adequately describe the fit of an GP was agreed as: the manufacturer, brand and lens parameters; settling time; comfort on a 5 point scale; centration; movement on blink on a ±2 scale; and the Primary Fluorescein Pattern in the central, mid-peripheral and edge regions of the lens averaged along the horizontal and vertical lens axes, on a ±2 scale. On average 50-60% of practitioners selected the median grade when subjectively rating fluorescein intensity and this was correlated to objective quantification (r=0.602, p<0.001). Objective grading suggesting horizontal median fluorescein intensity was generally symmetrical, as was the vertical meridian, but this was not the case for subjective grading. Simulated fluorescein patterns were subjectively and objectively graded as being less intense than real photographs (p<0.01). CONCLUSION: GP fit recording can be standardised and simplified to enhance GP practice.

Fluorophotometric determination of histone with 3,4,5,6-tetrafluoro-2-carboxyphenylfluorone-manganese(II) complex and its characterization.

A simple fluorophotometric method for the determination of histone has been developed. This method involves a fluorescence quenching reaction that results in the formation of a complex of manganese(II), 3,4,5,6-tetrafluoro-2-carboxyphenylfluorone (TFCPF), and histone in a non-ionic surfactant micellar medium. The calibration curve was found to be linear in the range of 0.5 to 2.0 µg/mL. The binding parameters (n, number of binding sites; K, binding constant) and thermodynamic parameters (ΔG(0), change in Gibbs free energy; ΔH(0), change in enthalpy; ΔS(0), change in entropy) were investigated spectrophotometrically for the elucidation of the reaction mechanism. The resulting binding parameters (n=4.08 and K=3.16×10(4) m(-1) at 25°C) and thermodynamic parameters (ΔG=-25.83 kJ/mol, ΔH=-9.83 kJ/mol, and ΔS=53.68 J/(mol K)) suggest that the colored complex in this reaction system is an ion-association complex between manganese(II)-TFCPF and histone.

An improved fluorophotometric method for tear turnover assessment.

PURPOSE: Scanning fluorophotometry is considered the "gold standard" to determine tear turnover rates (TTR). In this study, we attempted to improve the precision of basal TTR by fluorophotometry through a number of methodological changes. METHODS: By means of a timer program that produces audio cues, a new methodology that ensures confluence and a constant thickness of the tear film and minimization of reflex lacrimation as a result of the inhibition of the blink reflex was developed. This was compared with the standard protocol, both in a paired study and by a review of unpaired data. The minimum length of time required to monitor TTR measurements was also investigated. RESULTS: A significant improvement in correlation coefficient (r) of the log decay curve was observed as a result of changes in the protocol in both the paired (p = 0.016) and unpaired study (p < 0.0001). We determined that it was sufficient to monitor TTR for 10 min to obtain accurate results. CONCLUSIONS: We advocate that the changes be adopted as widely as possible for the precise and rapid measurement of basal tear turnover rates.

A standardized visual scale for evaluation of tear fluorescein clearance.

OBJECTIVE: To evaluate the correlation and the agreement between a validated fluorometric technique (fluorescein clearance test) and a newly developed, clinically practical standardized visual scale to evaluate tear fluorescein clearance. Also, the ability of this new method to distinguish healthy persons from patients reporting ocular irritation associated with meibomian gland disease (MGD), aqueous tear deficiency (ATD), or both was tested. DESIGN: Case-controlled study. PARTICIPANTS: Healthy persons (n = 32), patients with MGD associated with rosacea (n = 30), patients with noninflammatory atrophic MGD (n = 24), and patients with ATD (n = 39) were evaluated. There was a similar age and gender distribution in each group. METHODS: Each subject completed a symptom questionnaire and had the following tests performed: fluorescein clearance test (FCT), standardized visual scale test (SVST), corneal fluorescein staining, Schirmer 1 test, corneal and conjunctiva sensitivity, and eyelid margin and meibomian gland examination. MAIN OUTCOME MEASURES: The FCT was performed with a CytoFluor II fluorophotometer by measuring the fluorescein concentration in minimally stimulated tear samples collected from the inferior tear meniscus 15 minutes after instillation of 5 microl of 2% sodium fluorescein. The SVST score, ranging from 0 to 6, was obtained by comparing the colors of the standardized visual scale with the color of the lateral inferior tear meniscus immediately before tear collection for the FCT. Severity of ocular irritation was assessed with a symptom questionnaire. Schirmer 1 test (without anesthesia), biomicroscopic meibomian gland evaluation, and corneal fluorescein staining were performed. Corneal and conjunctival sensitivity scores were assessed with the Cochet-Bonnet aesthesiometer. The correlation and the agreement between FCT, FCT corrected for Schirmer test (corrected FCT), SVST, and SVST corrected for Schirmer test (corrected SVST) in separating healthy persons from patients with ATD, MGD, or both were studied. Furthermore, the correlations of FCT, corrected FCT, SVST and corrected SVST, corneal fluorescein staining score, corneal and conjunctiva sensitivity, meibomian gland and eyelid evaluation, and questionnaire score were studied. RESULTS: The FCT, the corrected FCT, the SVST, and the corrected SVST all showed strong correlation with irritation symptoms, corneal fluorescein staining, Schirmer 1 test score, cornea and conjunctiva sensitivity, and meibomian gland and eyelid pathologic characteristics. The FCT, the corrected FCT, the SVST, and the corrected SVST had a sensitivity in diagnosing MGD, respectively, of 67%, 72%, 69%, and 76%, and of 95%, 97%, 97%, and 97% in diagnosing ATD. The specificity was, respectively, 97%, 96%, 97%, and 94%. CONCLUSIONS: The new standardized visual scale test was equivalent to fluorometric assessment of tear clearance in its correlation with irritation symptoms, ocular surface and eyelid disease, and ocular surface sensitivity. Its ability to separate healthy persons from patients with MGD and ATD was improved by applying a correction factor based on Schirmer test score. The new standardized visual scale test is an accurate and practical method for clinical assessment of fluorescein tear clearance.

Ocular fluorometry: standardization and instrumentation development. A Concerted Action in the European Community (EUROEYE).

A Concerted Action on Ocular Fluorometry, stressing standardization and instrumentation development has been funded by the European Community. Agreement was reached on harmonization of protocols. The results obtained show that the protocols proposed for Clinical Ocular Fluorometry were generally appropriate and may be followed closely, with reproducible and meaningful results. In each group, areas for improvement could, however, be detected, particularly regarding facility of use of the newly developed softwares. The success of the ECNOF was very rewarding and every effort is being made to consolidate this success in the publication and dissemination of the agreed guidelines and results. The field of Ocular Fluorometry appears to have even more potential than was apparent at the beginning of this Concerted Action. The needs for instrumentation development have been clarified and four main directions where progress has been achieved are identifiable: spectral fluorescence analysis of naturally occurring ocular fluorophores, light scattering analysis of ocular structures and fluids, improved axial resolution for better quantification of ocular permeabilities and, finally, development of simple routine clinical instrumentation. Corneal and lens natural fluorescence appear extremely promising as indicators of disease status, particularly in diabetes. Blood-retinal barrier permeability has the potential to become a screening test isolating the eyes at risk for developing diabetic blindness and, therefore needing closer follow-up and earlier treatment. Light scattering methodologies particularly in association with ocular fluorometry, may allow improved monitorization of chronic inflammation, better therapeutical management of a variety a sight-threatening diseases.

[A new method in the analysis of vitreous fluorophotometry. Results in early diabetic retinopathy]. / Nouvelle méthode d'analyse de la fluorophotométrie du vitré. Résultats dans la rétinopathie diabétique débutante.

New methodology to analyze posterior vitreous fluorophotometry (PVF) data is described. Values for D, fluorescein vitreous diffusion coefficient and P, permeability of the blood retinal barrier (BRB) to fluorescein are obtained. D was found to be significantly greater in diabetic patients with minimal retinopathy compared with either controls or patients with no retinopathy. P values were not significantly different between diabetic patients and controls or between diabetic subgroups, confirming the absence of breakdown of the BRB, as assessed by PVF, in early diabetic retinopathy.