Determination of relative contribution of the superior and inferior canaliculi to the lacrimal drainage system in health using the drop test

Murgatroyd, Helen; Craig, Jennifer P.; Sloan, Brian

doi:10.1111/j.1442-9071.2004.00846.x

Cited by 34 publications

(19 citation statements)

References 32 publications

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“…For the normal drainage, tears are mainly drained through the lower canaliculus, 16 however, when the ocular fluid volume is significantly larger than normal, as for instillation, the upper canaliculus also contributes to drainage. 17 Therefore, for the case of extra fluid instillation, the term corresponding to the drainage rate through the canaliculi in Eq. (3) should be multiplied by a factor, the value of which is between 1 and 2, depending on the fluid volume remaining on the ocular surface.…”

Section: Dynamic Tear Balancementioning

confidence: 99%

A Mathematical Model for Ocular Tear and Solute Balance

Hui

Chauhan

2005

Current Eye Research

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Section: Dynamic Tear Balancementioning

confidence: 99%

A Mathematical Model for Ocular Tear and Solute Balance

Hui

Chauhan

2005

Current Eye Research

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“…Tears are moved into the lacrimal puncta by negative pressure created within the lacrimal drainage system during a blink 42 . The majority of tears drain through the lower puncta; 43,44 however, if drainage is impaired in the lower puncta, sufficient drainage can be obtained through the upper puncta 42,45,46 . Finally, tears move via gravity from the upper tear meniscus to the lower one.…”

Section: Tear Film Dynamicsmentioning

confidence: 99%

Osmolality and tear film dynamics

Stahl

Willcox

Stapleton

2012

Clinical and Experimental Optometry

133

102

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The tear film is a nourishing, lubricating and protecting layer that bathes the ocular surface. It is continuously replenished through cycles of production and elimination via evaporation, absorption and drainage. These processes are often referred to as tear film dynamics. Osmolality is an objective clinical measurement that provides insight into the balance of these complex tear film dynamics. Balanced tear production and elimination is vital for tear film integrity, stability and normal osmolality. Imbalances cause alterations of the tear film structure and composition, ultimately leading to tear film instability and measurable tear film hyperosmolality. Elevated tear film osmolality is considered a core mechanism in dry eye, forming the basis of dry eye symptoms and leading to ocular surface damage. Despite its immense potential in the diagnosis of dry eye, tear film osmolality is not commonly assessed. This review will focus on the current knowledge of tear film dynamics and tear film osmolality. The pre-ocular tear film is the outermost layer of the eye and is of critical importance to the health of the ocular surface. A continuous cycle of production, evaporation, absorption and drainage leads to a dynamic equilibrium in the pre-ocular tear film. Tear film osmolality or tear saltiness can be considered a consequence of these various factors in tear film dynamics.1 Homeostatic balance leads to tear film stability, enabling the tear film to fulfil its vital functions such as lubrication, nourishment and protection of the ocular surface.2,3 Homeostatic imbalance causes alteration of the tear film structure and composition, ultimately leading to tear film instability and tear film hyperosmolality.2 Measurement of tear film osmolality has been suggested as a gold standard in the diagnosis of dry eyes as elevated tear film osmolality is considered a core mechanism in symptoms and ocular surface damage in dry eye. 2,4,5 Despite its immense potential in the diagnosis of dry eye, measurement of tear film osmolality has not been amenable to in-office use and is largely confined to use in research. Newly available technology might increase its uptake by clinicians. This review focuses on the current knowledge of tear film dynamics and the relevance and clinical implications of tear film osmolality. TEAR FILM STRUCTURE AND FUNCTIONThe classical description of the tear film is a three-layered structure, with a predominant aqueous phase, a superficial thin oily layer, which interfaces with the environment, and a deep mucous layer at the base. 6,7 The thickness of the tear film was originally estimated to be 4 to 8 mm, with the aqueous layer being the thickest

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“…It is therefore difficult to determine whether repair of the lacerated or avulsed canaliculus is providing a functioning system. A previous study calculated, using the drop test, that the maximal outflow capacity does reduce if one punctum is occluded; however, this level is still much higher than normal basal tear production 5 . Murgatroyd et al .…”

Section: Discussionmentioning

confidence: 96%

“…A previous study calculated, using the drop test, that the maximal outflow capacity does reduce if one punctum is occluded; however, this level is still much higher than normal basal tear production. 5 Murgatroyd et al suggest that the capacity of the common canaliculus may limit flow along two patent canaliculi, thus allowing increased flow along a patent canaliculi when the other is occluded. 5 Because of this, some authors have advocated not repairing a monocanalicular injury; a survey of UK consultants with an oculoplastics' interest reported that only 40% would always repair a moncanalicular injury.…”

Section: Discussionmentioning

confidence: 99%

Determination of the function of a repaired canaliculus after monocanalicular injury by placing a punctal plug in the non‐involved punctum on the affected side

Rosser

Burt

Osborne

2010

Clinical Exper Ophthalmology

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In this study, a repaired monocanalicular injury provided a functioning system in 88% of cases. In previous studies, it has been shown that many patients are symptom-free with just one functioning canaliculus. However, a fully functioning canalicular system may help to prevent tearing under stress conditions, and will provide a viable system if the other canaliculus is irreparably damaged in the future. Therefore, repair is recommended.

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Determination of relative contribution of the superior and inferior canaliculi to the lacrimal drainage system in health using the drop test

Abstract: The drop test was found to provide a simple and repeatable method of assessing lacrimal drainage in a minimally invasive manner in the clinical setting. In healthy volunteers in the supine position 60% of maximal lacrimal outflow capacity occurs through the inferior canaliculus.

Cited by 34 publications

References 32 publications

A Mathematical Model for Ocular Tear and Solute Balance

A Mathematical Model for Ocular Tear and Solute Balance

Osmolality and tear film dynamics

Determination of the function of a repaired canaliculus after monocanalicular injury by placing a punctal plug in the non‐involved punctum on the affected side

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