Etty Bitton

Variability of the analysis of the tear meniscus height by optical coherence tomography.

Purpose. Tear meniscus height (TMH) is an established parameter indicative of tear film volume and has recently been determined using an optical coherence tomographer (OCT). The purpose of this study was to evaluate the inter and intra observer variability in TMH assessment using OCT. Methods. Ten subjects (6 M, 4 F; aged 32.5 ± 6.4 years) had 10 consecutive scans taken of their inferior central tear meniscus (5 scans originating at 90° and 5 origination at 270°) using the OCT2 (Humphrey-Zeiss). Images were analyzed by two observers using custom software on three separate occasions. Following a training session among observers, the images were reevaluated to assess differences in variability. Data were analyzed for differences within and across examiners, for the effect of examiner training and between scan directions. Results. The mean TMH and tear volume collapsed across subjects were between 0.24 and 0.25 mm and 25 to 27 nL/mm, respectively. No difference was noted within observers. An interobserver mean volume difference (p = 0.044) was present but was eliminated post training (p = 0.167). Variability was less with scans originating at 90°. Conclusions. The values of the TMH and tear volume are similar to those reported in the literature. Due to the interobserver differences observed, a training session between examiners may prove to be valuable, especially in a large or multicenter study.

Longitudinal Analysis of Precorneal Tear Film Rupture Patterns

The precorneal tear film is a complex structure that has attracted much attention over the years, especially in relation to dry eyes and contact lens (CL) wear. A healthy and stable tear film is essential for comfortable vision and successful CL wear.1 With an estimated 40% of the North American population suffering from dry eyes2 and some 60 million CL wearers worldwide,3 the need for simple, accurate, and cost-effective tests of tear stability has spawned much research both in the ophthalmic industry and in clinical practice.

Influence of the Blink Interval on Tear Meniscus Height in Soft Contact Lens and Nonlens Wearers

Purpose: Tear meniscus height (TMH) is an indirect measurement of tear film volume. This study investigated the temporal changes in the TMH during the blink interval in the morning (8–9 am) and at the end of the day (5–6 pm) in both soft contact lens (CL) and nonlens wearers (NLW). Methods: Fifty participants (25 CL; 25 NLW) were evaluated for their subjective symptoms, TMH, noninvasive break up time, and bulbar hyperemia at the am and pm visits on the same day. The TMH was measured at set intervals between 2 and 15 sec during the blink interval, using an optical coherence tomographer. Results: The NLW group revealed no changes in a variety of symptoms during the day, whereas the CL group reported an increase in dryness (P=0.03) and grittiness (P=0.02) over the day. For both groups, the TMH and calculated tear meniscus volume revealed lower values immediately after the blink and increased progressively afterwards, mainly due to reflex tearing. The am tear meniscus volume values tended to be higher than the pm values for both groups, but this was not significant (NLW P=0.13; CL P=0.82). Noninvasive break up time deteriorated during the day for both groups but was only significant for the CL group (P=0.002), whereas bulbar hyperemia revealed no statistically significant change for either group. Conclusions: Reflex tearing may play a substantial role in the TMH differences observed over the blink interval. Standardization of the time when a TMH measurement is performed will be valuable in comparing tear film clinical studies.

Subjective and objective variation of the tear film pre- and post-sleep.

Purpose. To date, few studies have correlated the overnight effects of the preocular tear film (POTF) with subjective symptoms. This study investigates the POTF volume and stability, bulbar hyperemia (BH), tear ferning (TF) and the participants subjective symptoms, pre- and post-sleep. Methods. Thirty subjects were recruited, consisting of two evenly distributed groups who were symptomatic of dry eye (DE) and those that were asymptomatic dry eye, determined using the McMonnies questionnaire. Subjects were evaluated at 10 p.m. (baseline), on waking at 7 a.m., and then hourly until 10 a.m. At each visit, tear meniscus height (TMH), various subjective factors, BH and POTF stability by non-invasive break-up time (NIBUT) were assessed. Tear collection was performed at 10 p.m, 7 and 10 a.m. for TF analysis. Results. With the exception of burning, all other symptoms (comfort, dryness, clarity of vision, and grittiness) revealed an overnight change (p < 0.05) within each group, but not between the two groups (p > 0.05). Both the tear meniscus height and BH were elevated upon waking and differed significantly between test times for each group (p < 0.05), but not between groups (p > 0.05). NIBUT was lower for the DE group (p < 0.001). The non-dry eye (NDE) group did not significantly alter over time (p > 0.05), but the DE group did (p = 0.004), with a longer NIBUT in the morning. TF demonstrated a degraded pattern upon waking for both groups (p < 0.05). Most of the changes returned to baseline within an hour after waking. Conclusions. The properties of the POTF undergo a change during extended periods of eye closure and the human POTF is different upon waking to that present immediately before sleep. Most of the parameters determined rapidly revert to baseline levels once the POTF is allowed to refresh.

Influence of eye position on the Schirmer tear test

INTRODUCTION The Schirmer test (ST) evaluates the volume of tears in potential dry eye candidates via a strip placed in the lower tear lake. Previously reported inconsistencies in the results may be in part due to the lack of standardization as to the methodology, e.g. the eye position during the test. The purpose of this study was to evaluate the effect of eye position on the ST score. METHODS . A ST was performed in a randomized fashion with and without anesthesia in three open eye positions (primary, superior and inferior) at 20° from each other. Palpebral aperture, age and a dry eye questionnaire (OSDI) were evaluated for correlation with the ST. RESULTS In the 20 non-dry eye volunteers (n=20, ages 18-40, mean OSDI score 10.5), the ST results were, as expected, lower overall (p < .001) with anesthesia (11.33 ± 7.78 mm) than without (19.74 ± 2.83 mm). The inferior gaze position resulted in higher values (p < .03) than the other two positions, regardless of the use of anesthesia. No correlation was noted between the palpebral aperture, age, questionnaire and the ST. CONCLUSION The ST seems to be influenced by the position of gaze. However, the mechanism for this, effect remains unclear. Further studies could focus on whether an inferior gaze of 20° compresses the tear film falsely, thereby elevating the tear volume. It is recommended that the clinician should adopt a standard eye position for the ST and that future reports provide specifics as to the methodology used.

Ex vivo heat retention of different eyelid warming masks

PURPOSE Meibomian gland dysfunction (MGD) appears to be the most common cause of evaporative dry eye, in which the meibum has an altered chemical structure that increases its melting point. Eyelid warming masks slowly transfer heat, preferably between 40 and 45°C to the inner meibomian glands, in an attempt to melt or soften the stagnant meibum. This ex vivo study evaluates the heat retention properties of commercially available masks over a 12-min interval. METHODS Five eyelid-warming masks (MGDRx EyeBag®, EyeDoctor®, Bruder®, Tranquileyes™, Thera°Pearl(®) were heated following manufacturers instructions and heat retention was assessed at 1-min interval for 12 min on a non-conductive surface. A facecloth warmed with hot tap water was used as comparison. RESULTS All masks reached above 40°C within the first 2 min after heating and remained so for 5 min, with the exception of the facecloth, which lasted only 3 min and quickly degraded to 30°C within 10 min. The Bruder® and Tranquileyes™ reached >50°C, after heating and the Bruder® maintained >50°C for nearly 6 min. The MGDRx EyeBag®, and Thera°Pearl® had the most stable heat retention between 2 and 9 min, remaining between the targeted temperature. CONCLUSIONS Heat retention profiles are different for commercially available eyelid warming masks. This ex vivo study highlights that despite the popularity of the time-honored facecloth, it is poor at retaining the desired heat over a 5-10 min interval. Clinical studies need to corroborate these results, remembering that ocular tissue parameters may be factors to consider.

In-vivo heat retention comparison of eyelid warming masks.

PURPOSE Meibomian gland dysfunction (MGD) is one of the most common causes of evaporative dry eye. Warm compresses (WC) are recommended as adjunct therapy to slowly transfer heat to the meibomian glands to melt or soften the stagnant meibum with targeted temperatures of 40-45°C. This clinical study evaluated the heat retention profiles of commercially available eyelid warming masks over a 12-min interval. METHODS Five eyelid-warming masks (MGDRx Eyebag(®), EyeDoctor(®), Bruder(®), Tranquileyes XR™, Thera°Pearl(®)) were heated following manufacturers instructions and heat retention was assessed at 1-min intervals for 12min. A facecloth warmed with hot tap water was used as comparison. RESULTS Twelve (n=12) subjects participated in the study (10F:2M, ranging in age from 21 to 30 with an average of 23.2±3.8years). Each mask demonstrated a unique heat retention profile, reaching maximum temperature at different times and having a different final temperature at the end of the 12-min evaluation. After heating, all eyelid warming masks reached a temperature near 37°C within the first minute. The facecloth was significantly cooler than all other masks as of the 2-min mark (p<0.05). CONCLUSIONS Reusability, availability and heat retention profiles should be considered when selecting an eyelid warming masks for adjunct WC therapy in the management of MGD. All masks tested, with the exception of the facecloth, demonstrated stable heat retention throughout the 12min, bringing further awareness that patient education is required to discuss the shortcomings of the heat retention of the facecloth, if only heated once.

The use of high modulus silicone hydrogel (SiHy) lens in the management of epithelial defects.

Corneal dystrophies are relatively rare bilateral anomalies. Meesman dystrophy is typically asymptomatic with little effect on visual performance. This case highlights the use of a high modulus silicone hydrogel (SiHy) lens in the management of an atypical presentation of Meesmans dystrophy with associated visual impairment due to epithelial defects. The selection of a SiHy material provided increased oxygenation to re-establish corneal integrity. However, selecting the appropriate modulus was an additional factor to consider in this case since it had a direct effect on the visual outcome. The higher modulus SiHy lenses provided a better visual success for this patient than one with a lower modulus. Modulus consideration may prove to be an additional factor in the lens choice of SiHy in the management of epithelial defects.

Unique advantage of gonioscopy for viewing an anterior pyramidal cataract.

Anterior polar cataracts (APC) are a relatively rare but well‐documented form of congenital cataract. Occasionally, these white disc‐shaped opacities protrude towards the anterior chamber with an inverse cone‐like morphology and are known as anterior pyramidal cataracts. These represent three to four per cent of all types of congenital cataracts. APCs portray a dominant mode of inheritance and generally do not progress over time. Due to their small size, APCs generally have little effect on vision and are simply monitored clinically. Photodocumentation of pyramidal cataracts has traditionally shown biomicroscopic views of the opacities. In addition to a review of APC, this report describes how a gonioscope offers a unique observational advantage in viewing an anterior pyramidal cataract.

The eyelash follicle features and anomalies: A review

The primary role of eyelashes is to protect and maintain the health of the lid margin. However, the mechanisms to fulfill this role are not fully understood. Unraveling these mechanisms will stand to greatly improve the efficiency of eye care professionals’ interventions in anomalies of the eyelashes. The aim of this article is to provide a review on eyelashes including highlights and new avenues for research; the biology of both the lash and its follicle; the pathophysiology and management of lash anomalies by eye care professionals; and the effect of iatrogenic factors on lashes. Using the database of Ovid MEDLINE, we reviewed studies specifically directed on human/mammalian eyelashes and key articles on current trends in scalp hair methodologies that can be applicable to lash research. The eyelash morphology, pigmentation and growth rate have been documented using techniques ranging from lash imaging to follicle immunohistochemistry. Furthermore, studies have demonstrated that the lash follicle is sensitive to many factors of the external environment, a variety of systemic/topical medications and cosmetics. Recently, aerodynamic studies using a mammalian eye model confirmed that an optimal lash length was needed so that eyelashes serve a protective role in reducing the number of particles that can reach the eye. Despite recent advances in lash research, studies are still scarce, due to the limited availability of the human lid for sampling. This review brings awareness that further research is needed with respect to eyelashes and will hopefully reduce the gap with scalp hair research.