Influence of Conjunctival Folds on Calculated Tear Meniscus Volume Along the Lower Eyelid

Anwendungsmöglichkeiten der optischen Kohärenztomographie beim trockenen Auge

Durch die stetige Weiterentwicklung und Verbesserung der Technik hat die optische Kohärenztomographie (OCT) in den letzten Jahren neue Möglichkeiten zur Beurteilung der Strukturen des vorderen Augenabschnittes eröffnet. Aufgrund der Darstellung kleinster Strukturen, wie beispielsweise des Tränenfilms, nimmt die OCT in der Diagnostik und Verlaufsbeurteilung des trockenen Auges eine immer wichtigere Rolle ein. Der vorliegende Beitrag gibt einen Überblick über die derzeitigen Einsatzmöglichkeiten der OCT beim trockenen Auge.

CLEAR - Evidence-based contact lens practice

Evidence-based contact lens -->practice involves finding, appraising and applying research findings as the basis for patient management decisions. These decisions should be informed by the strength of the research study designs that address the question, as well as by the experience of the practitioner and the preferences and environment of the patient. This reports reviews and summarises the published research evidence that is available to inform soft and rigid contact lens history and symptoms taking, anterior eye health examination (including the optimised use of ophthalmic dyes, grading scales, imaging techniques and lid eversion), considerations for contact lens selection (including the ocular surface measurements required to select the most appropriate lens parameter, lens modality and material selection), evaluation of lens fit, prescribing (teaching self-application and removal, adaptation, care regimen and cleaning instructions, as well as -->minimising risks of lens wear through encouraging compliance) and an aftercare routine.

CLEAR - Effect of contact lens materials and designs on the anatomy and physiology of the eye

This paper outlines changes to the ocular surface caused by contact lenses and their degree of clinical significance. Substantial research and development to improve oxygen permeability of rigid and soft contact lenses has meant that in many countries the issues caused by hypoxia to the ocular surface have largely been negated. The ability of contact lenses to change the axial growth characteristics of the globe is being utilised to help reduce the myopia pandemic and several studies and meta-analyses have shown that wearing orthokeratology lenses or soft multifocal contact lenses can reduce axial length growth (and hence myopia). However, effects on blinking, ptosis, the function of Meibomian glands, fluorescein and lissamine green staining of the conjunctiva and cornea, production of lid-parallel conjunctival folds and lid wiper epitheliopathy have received less research attention. Contact lens wear produces a subclinical inflammatory response manifested by increases in the number of dendritiform cells in the conjunctiva, cornea and limbus. Papillary conjunctivitis is also a complication of all types of contact lenses. Changes to wear schedule (daily disposable from overnight wear) or lens materials (hydrogel from SiHy) can reduce papillary conjunctivitis, but the effect of such changes on dendritic cell migration needs further study. These changes may be associated with decreased comfort but confirmatory studies are needed. Contact lenses can affect the sensitivity of the ocular surface to mechanical stimulation, but whether these changes affect comfort requires further investigation. In conclusion, there have been changes to lens materials, design and wear schedules over the past 20+ years that have improved their safety and seen the development of lenses that can reduce the myopia development. However, several changes to the ocular surface still occur and warrant further research effort in order to optimise the lens wearing experience.

Evaluation of tear meniscus height using different clinical methods

Clinical relevance: The height of the tear meniscus (TMH) is a generally accepted method to evaluate tear film volume, especially in dry eye diagnoses and management.Background: The purpose of this study was to evaluate the ability of different methods to measure tear meniscus height accurately and repeatably.Methods: Lower TMH of 20 volunteers (26.8 ± 5.6 years) was measured by two observers (OI and OII) using optical coherence tomography (OCT), slitlamp microscope image analysis, and with a reticule at low (8x) and high (32x) magnification. TMH was also evaluated by both observers by comparing TMH to thickness of the lid margin (lid-ratio; grade 0: TMH 1/2 lid margin thickness; grade 1: 1/3; grade 2: 1/4; grade 3: 1/5; grade 4: 1/6) and to the number of eyelashes fitting in the tear meniscus. Differences between observers were analysed by paired-t-test. Differences between OCT-TMH and other methods were analysed by ANOVA, and inter-observer repeatability by intra-class-correlation-coefficient (ICC). The ability to predict OCT-TMH was calculated by receiver operative characteristic (ROC) curve analysis.Results: There was no significant difference between OI and OII in all methods except of the eyelash-count-method (p = 0.008). For OI, TMH measured using a reticule at 8x (0.20 ± 0.05 mm) was significantly lower than OCT-TMH (0.24 ± 0.07 mm) (p = 0.032) but not at 32x (0.22 ± 0.01 mm; p = 0.435). TMH evaluated by the image software of the slitlamp (0.20 ± 0.05 mm) was significantly lower than OCT-TMH (p = 0.022). The lid-ratio-method and eyelash-count-method resulted in grades of 2.35 ± 1.22 and 2.85 ± 0.81, respectively. ROC analyses showed that only the 8x and the 32x magnification method could discriminate between normal and abnormal OCT-TMH. OCT had the best repeatability (ICC = 0.88; p < 0.001) followed by reticule using 32x magnification (ICC = 0.70; p = 0.004).Conclusion: The most reliable method to measure TMH was OCT followed by slitlamp using a reticule. TMH cannot be reliably evaluated by comparing it against lid margin thickness or number of eyelashes.

Clinical significance of contact lens related changes of ocular surface tissue observed on optical coherence images

PURPOSE

To investigate the relationship between the real contact lens imprint into the conjunctival tissue, observed by optical coherence tomography (OCT) and conjunctival staining and contact lens wearing comfort.

METHODS

17 participants (mean age = 26.6 SD ± 3.6 years; 7 females) were fitted with three different contact lenses base curves of the same silicone hydrogel custom lens type (Visell 50; Hecht Contactlinsen, Au, Germany) in a randomised order. One lens was optimally fitted according to the manufacturer's recommendation, one fitted 0.4 mm flatter and one fitted 0.4 mm steeper. After 4 h of lens wear the contact lens edge in the area of the conjunctiva was imaged nasally and temporally using OCT (Optovue iVue SD-OCT). To correct the artefact due to optical distortion with OCT, the imprint of all worn lenses was measured on a glass plate afterwards. Conjunctival staining in the limbal region after 4 h of lens wear was classified using the CCLRU Grading Scale. Comfort scoring was based on visual analog scales from 0 (very poor) to 100 (excellent).

RESULTS

The mean conjunctival imprint of all contact lens edges was 32.0 ± 8.1 μm before and 7.3 ± 6.5 μm after distortion correction of the OCT images. The distortion corrected conjunctival imprint with the 0.4 mm steeper lens (11.5 ± 6.2 μm) was statistically significantly greater compared to the optimally fitted lens (6.5 ± 5.9 μm) (One-way ANOVA followed Tukey-test; p = 0.017) and greater compared to the 0.4 mm flatter lens (3.9 ± 5.3 μm) (p < 0.001). There was no statistically significant difference between the optimally fitted lens and the 0.4 mm flatter lens (p = 0.209). The nasally measured imprint (11.4 ± 9.0 μm) was significantly greater than the temporally measured (3.3 ± 7.6 μm) (p < 0.001). There was no statistically significant correlation between the amount of conjunctival imprint and the graded conjunctival staining (p = 0.346) or the wearer's comfort (p = 0.735).

CONCLUSIONS

Contact lens edges imaged by OCT exhibited displacement artefacts. The observed conjunctival imprints are a combination of real conjunctival compression and artefacts. A deeper imprint of the contact lens into the conjunctiva caused by a steeper base curve was not related to clinically significant staining or changes in comfort after 4 h of lens wear. The observed differences between nasal and temporal imprint are likely to be caused by variations of conjunctival thickness and the shape of the underlying sclera.

Efficacy of Strip Meniscometry for Detecting Lacrimal Obstructive Diseases Among Patients With Epiphora

Purpose

Strip meniscometry (SM) is a new technique for evaluating tear film volume. The aim of the present study was to evaluate the efficacy of SM in detecting lacrimal obstructive diseases (LODs) in patients with epiphora retrospectively.

Methods

One-hundred sixty-six patients (53 men, 113 women; mean age: 72.4 ± 8.0 years) who were referred to Saitama Medical University Hospital with epiphora as their chief complaint were enrolled; finally, 72 patients with and 89 patients without LOD were examined. We assessed tear volume using SM, tear meniscus height (TMH), tear meniscus area (TMA), and Schirmer-1 test values. Patients with LOD underwent lacrimal intubation surgery to treat their epiphora; their SM scores were assessed before and 8 weeks after surgery.

Results

SM, TMH, TMA, and Schirmer-1 values were significantly higher in the LOD group (10.80 ± 3.63 mm, 0.49 ± 0.24 mm, 0.06 ± 0.06 mm², 18.46 ± 8.00 mm, respectively) than in the non-LOD group (5.44 ± 3.20 mm, 0.30 ± 0.18 mm, 0.03 ± 0.04 mm², 11.84 ± 7.16 mm). The area under the receiver operating characteristic curve (AUC) for SM was 0.88, the sensitivity and specificity were 82% and 84%. The AUC was significantly larger for SM than for the Schirmer-1 test and TMA. The SM scores significantly improved after surgery (5.30 ± 2.20 mm) compared with those before (10.69 ± 3.20 mm).

Conclusions

SM was significantly better than the Schirmer-1 test, TMH, and TMA for detecting LOD and evaluating the effect of lacrimal surgery.

Translational Relevance

SM, widely used for dry eye, is also useful for using epiphora.

Lid-Parallel Conjunctival Folds and Their Ability to Predict Dry Eye

PURPOSE

The observation of lid-parallel conjunctival folds (LIPCOF) is reported to be useful in dry eye diagnoses. Around 70% of the European clinicians use this test in a dry eye clinic. This study investigated the sensitivity and specificity of LIPCOF to predict dry eye.

METHODS

Ocular Surface Disease Index (OSDI) outcome, noninvasive break-up time (NIKBUT) using the Keratograph (Oculus, Wetzlar, Germany), and LIPCOF of 148 randomized selected patient reports (88 females; mean age=37.0±12.9 years) from 3 different sites were analyzed. Subjects were divided into dry eye and non-dry eye groups by OSDI only, named symptomatic dry eye (OSDI scores ≥15) and by a composite score (OSDI scores ≥15 and NIKBUTaverage of ≤9 sec).

RESULTS

Lid-parallel conjunctival folds (temporal, nasal, Sum [=temporal+nasal]) were significantly correlated to OSDI and to NIKBUTaverage (Spearman; r>-0.185, P<0.013). NIKBUTaverage (r=-0.322; P<0.001) was significantly correlated to OSDI scores. Based on the OSDI questionnaire, 37.2% of the subjects were symptomatic and 14.7% were positive for dry eye based on the composite score. Lid-parallel conjunctival folds were a significant discriminator between healthy and dry eye subjects (P≤0.001). The areas under the receiver operating characteristic curve for temporal LIPCOF, nasal LIPCOF, and LIPCOF Sum were 0.716, 0.737, and 0.771, respectively, for the symptomatic dry eye group and 0.771, 0.719, and 0.798, respectively, for the composite dry eye group.

CONCLUSIONS

As LIPCOF demonstrated high predictive ability of dry eye; it appears to be a promising test in the diagnoses of dry eye.

Lid-parallel conjunctival fold (LIPCOF) morphology imaged by optical coherence tomography and its relationship to LIPCOF grade

PURPOSE

Lid-parallel conjunctival folds (LIPCOF) are a well-accepted clinical sign in dry eye diagnosis. Commonly, LIPCOF is classified by grading the number of folds observed by slit-lamp microscope. This study investigated the relationship between subjective grading scale and LIPCOF morphology imaged by optical coherence tomography (OCT).

METHODS

Temporal and nasal LIPCOF of 42 subjects (mean age 27.3 ± 8.4 (SD) years; 13 M, 29 F) were observed and classified by an experienced optometrist using the Pult LIPCOF grading scale (0: no permanent, lid-parallel conjunctival fold; 1: one fold; 2: two folds, 3: three or more folds). Additionally, LIPCOF cross-sectional area (LIPCOF-A) and fold count (LIPCOF-C), as imaged by OCT (Cirrus HD; Carl Zeiss Meditec, Jena, Germany), were analysed with ImageJ 1.50 (http://rsbweb.nih.gov/ij). Correlations between subjective grading and LIPCOF-A and LIPCOF-C were analysed by Spearman correlation, differences between subjective grading and LIPCOF-C were analysed by Wilcoxon test.

RESULTS

For temporal and nasal sectors, mean subjective LIPCOF grade was 1.43 ± 0.86 grade units and 0.57 ± 0.80 grade units, mean LIPCOF-C was 1.67 ± 0.82 folds and 0.69 ± 0.78 folds, and mean LIPCOF-A was 0.0676 ± 0.0236mm² and 0.0389 ± 0.0352 mm², respectively. Subjective temporal and nasal LIPCOF grade was significantly correlated to LIPCOF-C (r = 0.610, p < 0.001 and r = 0.645, p < 0.001, respectively), and to LIPCOF-A (r = 0.612, p < 0.001 and r = 0.583, p < 0.001, respectively). LIPCOF-C was not statistical different to subjective LIPCOF grade (p = 0.07 and p = 0.239; temporal and nasal sectors, respectively).

CONCLUSIONS

OCT allows for better imaging of finer details of LIPCOF morphology, and especially of LIPCOF area. OCT evaluation of LIPCOF area correlated well with subjective grading and appears to be a promising objective method for LIPCOF classification.