Drug Acting on Eye.pptx

Drug Acting on Eye.pptx

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  DRUG ACTING ON EYE SwatiG. Patil M . Pharm Pharmaceutics
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  Eye is thespecial sense organ of the sight , having limited systemic access by blood-retinal , blood- aqueous and blood- vitreous barrier. Because of which the eye exhibit unusual characteristics . Eye abnormalities include myopia ( near sightedness ) , hyperopia (far sightedness ) , Presbyopia, cataract, Introduction
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  • These arePharmacological agent Producing mydriasis are known as Mydriatics. Mydriasis means dilation of pupil. There are the two types of muscles in the iris that regulate the size of pupil . • These are the circular muscle ( sphincter muscles) and radial muscles (dilator) . Mechanism : • Pupilae supplied by parasympathetic as well as sympathetic nerve fibre . • The parasympathetic supply is through occulomotor nerve and supplies constrictor pupilae i.e. circular muscle fibres. The sympathetic supply is through superior cervical ganglion and supplies to dilator pupilae. • When Mydriatics instilled in the eye , it causes relaxation of circular muscle fibre, i.e. constrictor pupilae and
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  • This causedflattening lens which is referred as Mydriasis. Because of Mydriasis, focal length of pupil is also increase which is fix the sight for far vision, i.e. person can see the object which far away but fails to observe those that are too near , this termed cyclopegia.
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  • Miosis meansconstriction of pupil And the agent that produce meiosis are called as Miotics. Mechanism: Pupilae supplied by parasympathetic as well as sympathetic nerve fibre . • The parasympathetic supply is through occulomotor nerve and supplies constrictor pupilae i.e. circular muscle fibres. • When Miotics are instilled in the eye , the causes contraction of circular muscle fibre, i.e. constrictor pupilae and relaxation of radial muscle fibre i.e. dilator pupilae. This caused marked reduction in size of pupil whish is referred as miosis.
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  Because of Miosis, focal length of pupil is also reduced, person can see the object which are near but fails to observe those that are far away , this termed as spasm of accommodation
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  [A] Mydriatics and cycloplegics [B]Miotics and Spasm of accommodation 1.Parasympatholitics 1. Parasympathomimetics ( cholinergic) Atropine Homotropin Cyclopentolate Tropicamide Scopolamine Acetylcholine Methacholin Carbachol Pilocarpine Physostigmine Edrophonium 2. Sympathomimetic 2. Sympatholytic Adrenaline Phenylephrine Cocaine Ephedrine Gaunethedine Tolazoline Dibenamine Drug acting on eye ball are classified as :
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  Drugs  Miotics 1. Physostigmine •Physostigmine potentiate the muscarinic like action of acetyl choline by antagonism of cholinesterase to cause Miosis , ciliary spasm and fixing of lens for near vision. • The intraocular pressure may fall due to the opening of filtration angle by stretched iris which is facilitate reabsorption of the aqueous humor. • Accommodation returns to normal in 3 hours but Miosis start in few minute, is maximal in 30 minutes band may not wear off for several days. • Physostigmine is used to treat glaucoma or to counteract the effect of Mydriatics. • Drug with similar effect are Ecothiopate ( long acting cholinesterase) and pilocarpine , an alkaloid which stimulate
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  Adrenergic drug likeDibenamine which is alpha- adrenergic receptor blocker produce Miosis by causing relaxation of radial muscle (dilator) . It dose not affect accommodation and intraocular tension . Dibenamin e
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  • Pilocarpine Itis cholinergic agonists . Primarily used in treatment of glaucoma , used in the form of eye drop solution pilocarpine hydrochloride 2%, 4% and pilocarpine nitrate 2 %, 4% , one drop up to four times daily. • Indications : Chronic open-closure glaucoma , ocular hypertension an din emergency treatment of acute angle-closure glaucoma. • Contraindication : Acute iritis, Acute uveitis, inflammation of anterior segment. • Adverse effect : Eye pain , blurred vision ,ciliary spasm, lacrimation, myopia. Pilocarpin e
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  • A specificbeta-adrenergic blocker drug. It is combined with carbonic anhydrase inhibitor , dorzolamide in a single medication. Such combination reduces the number of drop needed and may improve compliance . • Indication : Ocular hypertension , chronic open-angle glaucoma. • Contraindications : Uncontrolled heart failure , bradycardia heart block , asthma. • Dosage : Eye drops instillation 1 drop ( 0.25 % or 0.5 % ) twice daily. Timol ol
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  • Mydriasis canproduced by sympathomimetic drug like adrenaline and phenylpepinefrine . • These drug dilate the pupil though have little effect on accommodation . • The intraocular pressure may fall. • Cocaine also stimulate adrenergic mechanisms to give similar effect. Mydriatic s Mydriatics
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  • Mydriasis canalso be produced by anticholinergic drug like atropine and Homotropin. These drugs antagonize the muscarinic like action of acetyl choline . These drug produce dilation of the pupil ( i.e. mydriasis ) paralysis of accommodation (i.e. cyclopegia) with fixation of the lens for vision. • A 1% of solution of atropine instilled into the conjunctival sac produces maximal dilation of pupil in about 30-60 minutes for 7-10 days. More than an hour may be necessary for the paralysis of accommodation which persist 3-5 days. • Mydriatics such as atropine are used to dilate the pupil to facilitate ophthalmological examination . In the inflammation of iris , they will rest the eye and the dilating of the pupil will keep the iris away from the lens and prevent adhesions . The persistent mydriasis may cause blockade for the filtration angle
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  • Anticholinergic drugatropine by blocking muscarinic cholinergic effects paralyze the pupillary constrictor muscle resulting into dilation of pupil ( mydriasis ). In the addition the paralysis of ciliary muscle result into paralysis of accommodation ( cyclopegia ) . • Therapeutic uses/ Indications: It is used for cycloplegics refraction procedures , particularly in children , iris , uveitis, Antispasmodic etc. • Dosage : Atropine Sulfate eye drops , solution 0.1 % . 0.5% and 1 %. • Contraindications : Angle-closure Glaucoma. Atropine
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  Drug used in Glaucoma •Glaucoma is an ocular disease characterized by elevated intraocular pressure which causes damage of optic nerve head producing visual loss. • The damage to optic nerve head and visual loss is probably due to ischemia and may be attributed to direct pressure on nerve. Objective of management of
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  The various agentused are as follows : 1.Beta adrenergic blocker : Timolol , betaxolol , levobunolol They are the beta blockers effective in glaucoma. They act by reducing the formation of aqueous humour. 2. Miotics : Pilocarpine and physostigmine . They produce contraction of ciliary muscle . 3. Alpha adrenergic agonist : Apraclonidine and brimonidine. Both are congeners of clonidine. They act by decreasing aqueous humour production. 4. Carbonic anhydrase inhibitor: Acetazolamide belongs to this group . It acts by inhibiting the generation of