Role of instrumental factors in Meibomian gland contrast assessment.

PURPOSE: Meibomian gland contrast has been suggested as a potential biomarker in Meibomian gland dysfunction. This study analysed the instrumental factors related to contrast. The objectives were to determine whether the mathematical equations used to compute gland contrast (e.g., Michelson or Yeh and Lin), impact the ability to identify abnormal individuals, to ascertain whether contrast between the gland and the background could be an effective biomarker and to assess whether using contrast-enhancement on the gland image improves its diagnostic efficacy. METHODS: A total of 240 meibography images from 40 participants (20 controls and 20 having Meibomian gland dysfunction or blepharitis), were included. The Oculus Keratograph 5M was used to capture images from the upper and lower eyelids of each eye. The contrast of unprocessed images and those pre-processed with contrast-enhancement algorithms were analysed. Contrast was measured on the eight central glands. Two equations for contrast computation were used, and the contrast both between glands and within a gland were calculated. RESULTS: Significant differences were found between the groups for inter-gland area in the upper (p = 0.01) and lower eyelids (p = 0.001) for contrast measured with the Michelson formula. Similar effects were observed when using the Yeh and Lin method in the upper (p = 0.01) and lower eyelids (p = 0.04). These results were obtained for images enhanced with the Keratograph 5M algorithm. CONCLUSIONS: Meibomian gland contrast is a useful biomarker of disease related to the Meibomian glands. Contrast measurement should be determined using contrast-enhanced images in the inter-gland area. However, the method used to compute contrast did not influence the results.

A Comparative Study of Two Imaging Techniques of Meibomian Glands.

In the present study, two different meibographers, Oculus Keratograph 5M (K5M) that uses 840 nm infrared light and the Visible Light Non-Contact Meibographer (VLNCM) that uses 610 nm visible light have been used to obtain meibography images from normal and Meibomian Gland Dysfunction (MGD) population. The main objective has been to validate and demonstrate that the use of visible light is useful for observation and quantification of MG in clinical practice. Twenty participants were enrolled in this prospective study. The upper eyelids of one randomly chosen eye were used to obtain results. Forty images were captured and analysed. Three specialized observers were recruited to grade images using Pult and Riede Pult 5-degree scale, in two different sessions. Intra-observer agreement between sessions for both devices was shown. Inter-observer variability analysis showed discrepancy between meiboscores obtained from observers with K5M (p-value < 0.05), except for session 2 in the pathology group, while no statistical difference was found with VLNCM. Repeatability analysis found no statistically significant differences between sessions. Correlation between meibographers showed no statistically significant difference and a moderate correlation coefficient between meiboscores graded with the two devices. The current study suggests that VLNCM can allow MG to be properly visualized and classified in the upper eyelids.

Improving ocular surface comfort in contact lens wearers.

PURPOSE: Contact lens discomfort (CLD) is a major concern that can lead to the decreased or abandoned use of contact lenses. Contact lens users with dry eye disease are more likely to present with CLD. This study was conducted to evaluate the efficacy of a bioprotective preservative free, hypotonic, 0.15% hyaluronic acid (HA)-3% Trehalose artificial tear in managing dry eye symptoms in contact lens wearers. METHODS: A prospective, single-arm, observational pilot study to evaluate the effectiveness of treatment with HA-Trehalose artificial tears in contact lens wearers (N = 33) aged 18-45 years with symptoms of ocular discomfort. Participants used a preservative-free, hypotonic HA-Trehalose artificial tear (1 drop/4 times per day) for 84 days. Participants were assessed using Visual Analogue Scale (VAS) for dry eye symptoms (pain, photophobia, dry eye sensation, blurry vision, foreign body sensation, itching, tingling/burning, and sticky eye feeling), Ocular Surface Disease Index (OSDI), Contact Lens Dry Eye questionnaire (CLDEQ-8), Berkley Dry Eye Flow-Chart (DEFC) on Day 0 and Day 84 and tear break-up time (TBUT), ocular surface staining with fluorescein and lissamine green, tear meniscus evaluation, and visual acuity on Day 0, 35, and 84. RESULTS: All VAS symptoms (except tingling/burning and sticky eye feeling), OSDI, CLEDQ-8, and DEFC showed statistically significant (p < 0.05) improvement from baseline (Day 0) to Day 84. Similarly, corneal (fluorescein) and conjunctival (lissamine green) quality improved during the study (p < 0.05 at Day 84 versus baseline). Tear break-up time (TBUT), conjunctival (lissamine green) staining, and tear meniscus decreased but the changes were not statistically significant. Visual acuity did not change during the study. There were no ocular or systemic adverse events. CONCLUSIONS: This study showed that the instillation of a preservative-free, hypotonic, HA-Trehalose artificial tear in contact lenses wearers with dry eye syndrome significantly improved symptoms and reduced associated signs such as corneal and conjunctival staining.