Abstract
Purpose: :
Meibomian Gland Dysfunction (MGD) is a prevalent and chronic condition associated with lid margin disease and keratoconjunctivitis sicca. Novel tear film analysis technologies (OPI 2.0 System; Abelson 2010) were developed to better understand tear film and blink dynamics. The purpose of this study was to evaluate dry eye signs and symptoms in adult subjects with and without MGD using the OPI 2.0 system.
Methods: :
The OPI 2.0 system provides data on: 1. Tear film break up time (TFBUT) 2. Area of corneal exposure and 3. Blink performance (rate and type) during a 2 minute video/computer recording. Following screening (Visit 1), subjects were evaluated using the OPI 2.0 system at Visit 2. Squeeze blinks (blinks with higher pressure and prolonged lid contact), corneal fluorescein staining and ocular discomfort were also assessed.
Results: :
The study was completed by 14 subjects diagnosed with MGD (poor gland secretion quality, color, and viscosity) and 5 non-MGD subjects (controls). Versus controls, MGD subjects had significantly worse lid margin redness scores (p=0.046), greater lash loss (p< 0.001), greater ocular discomfort (p <0.001), and higher levels of keratitis (p=0.046). The proportion of full blinks and squeeze blinks was significantly greater in MGD subjects than controls (p=0.044). There was no significant difference between groups in the IBI (p=0.919). Tear film stability showed no significant difference between groups in video recorded TFBUT or area of corneal break up.
Conclusions: :
The surprising discordance of the presence of MGD and keratitis alongside normal tear film break up times and low levels of corneal exposure are noted, suggesting that keratitis results from other causes (elevated inflammatory cytokines). It is possible that the act of lid contact occurring with a complete blink better facilitates excretion of meibum from the glands and uptake into the tear film. Blink pattern alterations to include more complete and squeeze blinks may help MGD subjects account for poor meibum secretions and present a relatively stable tear films; however the benefit provided by this blink profile change is uncertain.
Keywords: eyelid • clinical research methodology