Term
| Are reflex tears part of the basal tear film? |
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Definition
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Term
| Which layer of the tear film is thought to control evaporation from the anterior corneal surface? |
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Definition
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Term
| What are the three layers of the basal tear film? |
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Definition
| The mucin inner layer, the middle aqueous layer, the outer lipid (oily) layer |
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Term
| The tear film has a variety of functions. What are they? |
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Definition
1.Smooths surface of the corneal (optical) 2. Protect/buffer/lubricate
3. Flushing action/garbage pickup
4. Bacteriostatic 5. Healing
6. Osmotic gradient important for cornea 7. Nutrition - primary oxygen conduit for cornea |
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Term
| If a patient is having hormonal issues, what symptom are they most likely to present? |
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Definition
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Term
| What is the autoimmune disorder that destroys the lacrimal gland and leads to tear film problems? |
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Definition
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Term
| What are some foreign agents that can cause tear film problems? |
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Definition
| make-up, medications, CL, trichiasis |
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Term
| Can lagophthalmos cause tear film problems? |
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Definition
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Term
| What is stenosis? Can it cause tear film problems? |
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Definition
Small puncta
YES - tears pool instead of draining properly and it causes the consistancy of the tear film layers to be thrown off |
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Term
| How much of the clinic's patients present with their cheif complaint of dry eye? How many of the females aged 40-60 present with their cheif complaint as dry eye? |
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Definition
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Term
| Is the lacrimal gland an exocrine or endocrine gland? Glands of Moll? Glands of Zeiss? Meibomian? |
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Definition
Exocrine
Moll - exocrine apocrine
Zeiss - exocrine holocrine |
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Term
| The inner mucin layer is made of mucous in "gel" dissolved in what? |
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Definition
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Term
| The aqueous layer of the tear film consists of soluble whats? |
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Definition
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Term
| The lipid layer of the tear film consists of a ____ inner layer and a ______ thicker outer layer |
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Definition
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Term
| Is mucin a lipoprotein or a glycoprotein? |
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Definition
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Term
| The glycocalyx plays a role in what of the tear film? |
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Definition
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Term
| The microvilli on the glycocalyx serve what function? |
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Definition
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Term
| The glyocalyx interacts with what layer of the tear film? |
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Definition
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Term
| Recent studies indicate that the tear film is composed primarily of what? |
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Definition
| An aqueous-mucin gel gradient covered with a lipid layer |
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Term
| Recent studies indicate that the aqueous-mucin phase of the tear film is necessary for what? |
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Definition
| Hydrophilic state as well as transporting growth factors to maintain corneal health and reducing the shearing force of a blink |
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Term
| Mucin is a high molecular weight glycoprotein that consists of a protein backbone with sugar side chains. These sugar side chains interact with the sugar chains of what to provide some tear film stability? |
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Definition
| The glycocalyx on apical surface of the epithelium |
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Term
| The mucin of the tear film functions to provide a _____ surface, as well as lubricating and healing. |
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Definition
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Term
| How many types of mucin are there? |
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Definition
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Term
| MUC5AC is secreted by conjunctival goblet cells that are located where? |
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Definition
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Term
| Non goblet epithelial cells of the cornea and conjunctiva secrete what two types of mucin? |
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Definition
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Term
| Detachment of the mucin at the what is necessary to refresh the tear film at each blink? |
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Definition
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Term
| Is mucin secreted as a thick or thin thread? |
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Definition
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Term
| "Sleep", "Sleepies", or "eyecrud" found on the eyes in the morning is do to what? |
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Definition
| Mucin being trapped by caruncle cilia during slepp |
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Term
| Mucin is removed as an insoluble complex and washed away by what? |
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Definition
| Lacrimal drainage thru puncta |
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Term
| What cell forms the "gel" phase of the mucin layer? |
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Definition
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Term
| The production of mucin is considered a "gray area". Adler's suggests that mucin production occurs due to what? |
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Definition
| Sympathetic input via Norepi and NPY |
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Term
| What is the receptor agonist that is thought to mediate mucosal surface lubrication by stimulating the release of mucous and other tear components? |
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Definition
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Term
| These are the constituents of mucous gel that are also secreted by conjunctival goblet cells and interact with mucins to affect the rheology of mucus |
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Definition
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Term
| Do Secretory TFF-peptides function to influence migration rates in healing (mitogens)? |
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Definition
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Term
| MUC 1 and MUC4 are what type of epithelial cells? |
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Definition
| Non-goblet stratified squamous epithelial cells |
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Term
| Non-goblet stratified squamous epithelial cells form what in the mucin layer? What does this do? |
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Definition
Form thin inner 'glycolayx' of mucin layer
Makes mucin wetable and provides stability |
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Term
| Pathologic destruction of the goblet cells can occur how? |
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Definition
Vitamin A deficiency
Ocular pemphigoid
Steven's Johnson syndrome
Alkali burns
hypertonics |
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Term
| What makes up 90% of the tears in the form of dissolved mucins? |
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Definition
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Term
| What are the main aqueous sources of the eye? |
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Definition
Lacrimal gland (90-95%)
Accessory glands (Krauss, Wolfring) |
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Term
| The meibomian (tarsal) glands secrete what type of molecule? |
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Definition
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Term
| What are the two glands that produce lipid secretions for the eyelashes? |
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Definition
| Glands of Zeiss and Glands of Moll |
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Term
| In addition to reducing the evaporation of aqueous, what else does the lipd layer do? |
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Definition
Lubricates lid
Spreads with blink and carries aqueous
Contribute to the surface tension of tear film
Prevent overflow of tears at lid margin by providing local hydrophobic barrier |
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Term
| Clinically, disruption of the lipid layer leads to what? |
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Definition
Decrease in tear break up time
Clinical dye eye |
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Term
| Does the lipid layer behave as an oil film independent of the aqueous underneath? |
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Definition
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Term
| The lipid layer of the tear film changes with a blink. When the eye is opened, what does the lipid layer look like? |
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Definition
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Term
| Is there a "typical" composition of the lipid layer in the tear film? |
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Definition
NO - composed of MANY things
waxy esters, sterol esters, polar lipids, hydrocarbons, triglycerides, free sterols, free fatty acids |
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Term
| The secretion and regulation of the lipids in the lipid layer of the tear film is not well understood. Is it parasympathetically driven, sympathetically driven, hormonal, or all of the above? |
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Definition
| Since it is not well understood it could be all of the above, one of the above or a combination of a few. |
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Term
| The secretion and regulation of the lipids in the lipid layer of the tear film is not well understood. Is it parasympathetically driven, sympathetically driven, hormonal, or all of the above? |
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Definition
| Since it is not well understood it could be all of the above, one of the above or a combination of a few. |
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Term
| Does the polar or nonpolar lipid layer of the tear film interact with the aqueous layer to form a surfactant interface? |
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Definition
Polar
aqueous - polar layer - nonpolar layer
most inward ----------- most outward |
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Term
| Blepharitis is caused by a disruption of what? How does this occur? |
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Definition
| Disruption of the tear film Inflammation occurs and causes a release of phospholipidase from inflammatory cells and the lacrimal gland. The phospholipidase induces a release of histamines, prostaglandin and seratonin which disrupts the polar lipid layer |
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Term
| Meibomian dysfunction is caused by excess production of what? |
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Definition
| Excessive production of keratin in ductal epithelium clog the opening of the Meibomian gland. |
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Term
| In Meibomitis, what bacteria produces cholesterol esterase and fatty wax esterase which hydrolyze the meibomian lipid secretions and lead to an inflammation problem? |
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Definition
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Term
| How do you differentiate a chalazion from a hordeolum? |
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Definition
Differentiate btwn the two by pain and inflammation
Chalazion - not as red, not painful
Hordeolum - red, very painful |
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Term
| What is the common treatment for a hordeolum or chalazion? |
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Definition
| Both typically are treated with a warm compress and/or digital massage. If a hordeolum is bad, topical or oral antibiotics may be given |
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Term
| If a chalazion is very large, what must be done? |
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Definition
| The large walled-off cyst would have to be surgically removed |
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Term
| What determines the "wetting power" of tears on the corneal surface? |
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Definition
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Term
| Lipocalin is a protein secreted by the lacrimal gland that binds to what molecules in an effort to influence surface tension? |
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Definition
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Term
| What protein secreted by the lacrimal gland binds to lipids in order to influence surface tension of tears? |
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Definition
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Term
All of the following may cause an evaporative dry eye EXCEPT:
Grave's Disease
Blepharitis
Meibomitis
Diabetes
Chalazion |
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Definition
Diabetes
It causes an aqueous deficient dry eye because of the lack of input to the lacrimal gland |
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