Tear substitutes-ISHA...pdf(biochemistry pharmacology)
- 1. TEAR SUBSTITUTES ISHA OA
- 2. INTRODUCTION They are the first step of treatment given for patients with dry eyes to replace their natural tears. They lubricates the eye and help replace the natural moisture layer of tear film. They play a vital role to provide comfort by giving relief from symptoms of dry eyes. They are too used for individuals with aqueous tear deficiency since they have decreased tear film stability and volume.
- 3. 1. Ideally, tear supplements should fulfil the physicochemical role of a normal tear film 2. They should not disturb corneal metabolism nor be toxic to the eye, even with frequent use. 3. It should have a refractive index similar to that of cornea to see correctly. 4. Should enhance tear volume which is lost in dry eye condition.
- 4. 5. They should stay longer on the eye surface . Greater efficacy when there is greater viscosity than saline solutions. 6. They should be well tolerated i.e. , should be non toxic and non irritating. Inclusion of preservatives is necessary if they are to be dispensed for prolonged periods. Even in low concentrations , some preservatives cause irritation, burning or redness in eyes . pH of the tear supplement is also important to tolerability.
- 6. TEAR SUBSTITUTES EYE DROPS EYE OINTMENT EYE GEL OCULAR INSERT SOFT CONTACT LENS THERAPY PUNCTAL PLUG
- 7. They are lubricant drops which is formulated as artificial tear solutions which are commonly used. They usually contains inorganic electrolytes, preservatives, water soluble polymeric system. Various ions such as sodium chloride, potassium chloride etchelps to maintain tonicity and pH. Benzalkonium chloride, chlorobutanol, EDTA, ethyl paraben etcare used to prevent bacterial contamination.
- 8. INDICATIONS Lubricant for dry eyes. Temporary relief of burning, irritation due to dry eyes. Antibiotic drops given to prevent bacterial infections following ocular surgery. Refreshment of contact lens application.
- 10. 2. Second most common method. Primary base for ointments are petrolatum, lanolin etc.. When instilled in eye, they dissolve at the temperature of ocular surface and disperse with tear fluids. Ointment retains at the ocular surface longer. INDICATIONS 1. Exposure keratitis 2. Keratitis sicca (dry eyes) 3. After removal of foreign body 4. During and following surgery
- 11. SIDE EFFECTS Blurry vision because of its formulation at the instance , hence prescribed to use it during night before sleep.
- 12. A gelling agent with high water binding power that transforms from gel to liquid upon contact with ocular tissue. Provides long-lasting relief from dry eye symptoms.
- 13. They are sterile, thin, mono or multilayered , drug-impregnated, solid or semi-solid consistency devices placed in cul-de-sac or conjunctival sac, whose size and shapes are especially designed for ophthalmic application of individuals. ADVANTAGES No foreign body sensation. Reduced local side effects, irritation and toxicity. Increased contact time, therefore prolonged drug release.
- 14. DISADVANTAGES 1. Expensive than other supplements. 2. Patient may have discomfort placement and removal
- 15. 5. Hydrophilic bandage lenses kept on cornea. They are presoaked in drug solution. Drug release depends upon amount of drug soaking time and the drug concentration. ADVANTAGES Increased contact time with cornea. DISADVANTAGES Handling and cleaning Expensive
- 17. 6. They are tiny blocking devices placed in tear ducts called puncta, which are tiny opening in eyelids that drain tears from eyes . This helps keep the eye surface moist and comfortable , relieving dryness, itching ,burning and red eyes. Helps in prolonged action of natural tears along with artificial tears. DISADVANTAGES Scratchy or irritated feeling. May makes eye too watery . Costly
- 19. WHICH IS A BETTER TEAR SUBSTITUTE ?
- 20. All substitutes have their own advantages and disadvantages . EYE DROPS are so convenient to use , during all times consecutively. But its effect is for short period of time. When it comes to EYE OINTMENTS , it cannot be applied for day time, as it causes blurriness of vision. But it is best when it comes to its longevity of effect, it can be applied on night time, so their will be better penetration of the drug. So, comparatively a better tear substitute can be often choose by the severity of disease of that individual.
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