Artificial tears Flashcards
(24 cards)
What are test supplements used for. And tell me a little about this condition
Ocular lubricants- Use when tear dysfunction- dry eye.
Causes of dry eye- are Environment, Age and Allergy,office working conditions, atmospheric pollution, adverse effects of contact lens wear, refractive surgery.
It is Common, Persistent, Distressing + has limited treatment
px don’t always complain of a dry eye, but have tear dysfunction
most common > 50 yrs
can be mild to severe
severe/recurrent/persistent cases should be referred
An abnormality that leads to dry eye: Inadequate tear production and drainage. WHY
To supply nutrients to the eye
for moist conditions- evaporation and reduce surface temperature
to maintain osmotic balance
mechanical flushing
What does an aqueous deficiency lead to?
burning/itching
also hypertonicity- ocular dammage
Dry eye- Mucin deficiency
Mucin cells secrete surfactant mucin which educes surface tension and forms protective layer over cornea
if a reduction in goblet cells- then not a good mucin laer- irregular TBUT
Dry eye- Lipid abnormality
lipid layer reduces evaporation of aqueous
lipase- hydrolysis of meibomian gland dysfunction
lipid abnormality- quick TBUT
also blepharitis- due to mgd
What ocular abnormalities/ dyfunctions can cause a dry eye
aqueous deficiency mucin deficiency something wrong with lipid layer incomplete blinking dodgy epithelium layer adverse reaction and as a secondary pathology
How can incomplete blinking lead to dry eye
full closure of eye- for distribution of tears-
tear deficiency and exposure keratitis
Epitheliopathy- posh word for epithelial irregularity- and dry eye
irregular epithelium due to corneal lesions or keratoconus can lead to a thin unstable tear film
adverse reactions and dry eye
alters neurohumoral control of epithelial cell turnover- CNS drugs/beta blockers
Secondary pathology which results in dry eye
rheumatoid artheritis
derm conditions- acne rosecca/ sorjens disease, psoriarisis, sebohric dermatitis
What is available to treat dry eyes
ACETYLCYSTEINE (llube) POM
CARBOMERS (GelTears, Viscotears )
CARMELLOSE SODIUM (e.g. Optive ) HYDROXYETHYLCELLULOSE
HYPROMELLOSE (e.g. Isopto Plain /Alkaline)
LIQUID PARAFFIN (e.g. Lacri-Lube ) P medicine
MACROGOLS (e.g.Systane )
PARAFFIN, YELLOW SOFT (simple eye ointment)
POLYVINYL ALCOHOL (Sno-Tears, Liquifilm tears)
SODIUM CHLORIDE ( Minims NaCl)
SODIUM HYALURONATE (e.g. Hyabak )
SOYBEAN (Emustil)
what is acetlysysteine
POM
stings
mucolytic
breaks the linkage in disulphide bonds, to reduce mucous viscosity
also resolves filamentary keratitis- where little strands of degenerated epithetlium stick to the cornea
what are carbormers
to treat dry eye
most common
semi-solid formulations of high molecular weight polymers of acrylic acid
v viscous therefore may blur vision
however reduced frequency of instillation
comfort whilst sleeping
longer retention time- x7 compared to polyvinyl alcohol
reduce natural elimination of tears
reduced risk of allergy to benzalkonium chloride
whats a carmellose sodium
ocular lubricant
carboxymethylcellulose sodium
makes it unlikely to penetrate healththy cornea
and contact for up to 22 mins
whats hydroxyethylcellulose
A substituted cellulose ether – colloids- dissolve in water to produce colourless solutions of diff viscosity and have smoothing and cohesive properties.
Wetting of contact lenses and to prolong contact time of ocular drugs.
The Minims formulation - no preservatives but is formulated as hyetellose 0.44% w/w BP (which is hydroxyethylcellulose) and sodium chloride EP 0.35% w/w.
Whats hypomellose
Traditional choice of treatment for tear deficiency. Hydroxypropyl methylcellulose (HPMC) Cellulose ether and has been used for tear dysfunction for over 50 years. instilled frequently Ocular surface mucin is often abnormal in tear deficiency and the combination of hypromellose with acetylcysteine can be helpful. Most widely prescribed tear substitute
What’s luiqiud paraffin
it’s a P
lubricates the eye
but gives blurry vision
and don’t use with CL
macrogels
novel ph sensitive- becomes moe viscous with ocular ph
paraffin yellow soft
semisolid patroleum and mineral oil- and lanolin
melt on eye temp
blurry va- so use at night time ono
polyvinyl alcohol
to maintain tear film
and also used when mucin is reduced
Sodium chloride
for tear defficieny
and cl comfort
and to remove cl
just put salt in ur CL LOOOOOOOOOOOL
sodium hyaluronate
Viscoelastic high-molecular weight polysaccaride polymer.
Increases goblet cell density
reduces inflammation of the ocular surface in dry eye.
lubricates and protects the ocular surface
improves tear film stability
improves corneal wettability
what are other preparations available for dry eyes
Povidone (e.g. Oculotect
instead of artificial tears, what else can u do to reduce dry eye sx
Dietary manipulation: e.g.Omega-3/-6 fatty acids
Corticosteroids: have anti-inflammatory properties
NSAIDs: reduce formation of endogenous prostaglandins which may produce ocular inflammation that underpins dry eye.
Hormone supplements: e.g. androgens
Change ocular environment:
