DRUGS ACTING ON EYEBY MAI SAID SHOELA UNDER SUPERVISION OF PRF. DR. SAFAA EL REWANY PROFESSOR OF PHARMACOLOGY FACULTY OF MEDICINE UNIVERSITY OF ALEXANDRIA

OBJECTIVESLIST MAIN GROUPS OF DRUGS APPLIED ON THE EYE AND THEIR CLINICAL APPLICATIONS

DISCUSS THE LOCAL EFFECTS OF AUTONOMIC DRUGS ON THEIR RECEPTOR SITES IN THE EYE WITH RELEVANCE TO THEIR CLINICAL APPLICATIONS

IDENTIFY THE LINES OF TREATMENT OF SOME EYE DISEASES AS GLAUCOMA AND CONJUNCTIVITIS

STRUCTURE OF THE EYEANATOMICALLY EYE COMPOSED OF

ANTERIOR CHAMBER

POSTERIOR CHAMBER

ANTERIOR CHAMBER OF EYE

INCLUDES

CORNEA

IRIS

LENS

AQUEOUS HUMOUR

THE CORNEACORNEAL OR CONJUNCTIVAL REFLEXThe cornea and the sclera are supplied by sensory nerves. When the cornea is touched the corneal reflex is initiated i.e. the eye blinks on touching the cornea with a piece of cotton

DRUGS ACTING ON CORNEAINCLUDESLOCAL ANAESTHETICS DIAGNOSTIC DYES

TOPICAL ANTI-INFLAMMATORY

TOPICAL ANTI-INFECTIVE DRUGS

TEAR SUBSTITUTES LUBRICATING AGENTS

LOCAL ANAESTHETIC DRUGSINCLUDES1. Surface anaesthesia by lidocaine eye drops for : a. Tonometry: measurement of IOP b. Removal of corneal foreign bodies 2. Profound anaesthesia by tetracaine eye drops for: Removal of cataracts

DIAGNOSTIC DYESFluorescein 1%Used for diagnosis of corneal ulcers Denuded epithelium is stained bright green

Rose Bengal 1%Used for diagnosis dry eye Dead cells are stained red

TOPICAL ANTIINFLAMMATORY DRUGSINCLUDES 1. Steroidal anti-inflammatory drug anti

Used for anterior segment of eye inflammation as allergic conjunctivitis Example: Dexamethasone

2. Non-steroidal anti-inflammatory drugs Nonanti

Have anti-prostaglandins action anti Example: Ketophenac sodium

TOPICAL ANTI-INFECTIVE DRUGSINCLUDES

TOPICAL ANTI-BIOTICS

TOPICAL ANTIFUNGAL

TOPICAL ANTIVIRAL AGENTS

NEOMYCIN CHLORAMPHENICOL CIPROFLOXACIN

NYSTATIN SOLUTION

ACYCLOVIR FOR DENDRITIC CORNEAL ULCER

TEAR SUBSTITUTES AND LUBRICATING AGENTSEXAMPLE1. Methyl cellulose 2. Polyvinyl alcohol

USES1. Formation of artificial tears in dry eye conditions as Sjogrens syndrome Sjogren 2. Contact lens solution

THE IRISMUSCLES

SPHINCTER PUPILLAE MUSCLE PARASYMPATHETIC M3 RECEPTOR

DILATOR PUPILLAE MUSCLE SYMPATHETIC ALPHA 1 RECEPTOR

LIGHT REFLEXPRINCIPLE

Narrowing of pupil (miosis) when the eye is stimulated by light This miosis is due to contraction of constrictor pupillae muscle i.e. light reflex depends on integrity of parasympathetic supply of the eye Parasympatholytics abolish light reflex

THE LENSACCOMODATION REFLEX

It is the ability to increases the convexity of the crystalline lense to obtain a clear image of an object at various distances This is mediated through the parasympathetically innervated ciliary muscle, whose contraction causes suspensory ligaments relaxation thus increasing the lense curvature and diopteric power leading to accomodation for near vision

THE AQUEOUS HUMOUR

It is formed of highly vascularized ciliary body processes that absorb sodium selectively via carbonic anhydrase enzyme(70%) and ATPase enzyme(70%) system The aqueous humour circulates through the pupil and is drained in the canal of Schlemm then to episcleral veins Normally there is balance between aqueous homour formation and outflow and this keeps intraocular pressure within normal range (10(1021mmHg) 21mmHg)

CHANGES IN PUPIL SIZE

MIOSIS

NORMAL PUPIL

MYDRIASIS

AUTONOMIC DRUGS ACTING ON THE EYE

INCLUDES

MIOTICS

MYDRIATICS

MIOTICSINCLUDES

PARASYMPATHO MIMETICS

SYMPATHOLYTICS

MORPHINE

AS GUANETHIDINE

BY STIMULATION OF EDINGER WESTEFAL NUCLEUS

PARASYMPATHOMIMEYICSMECHANISM OF ACTIONThey stimulate M3 receptors in ciliary muscle M3 and constrictor pupillae muscle leading to: a. Miosis: constriction of the pupil b. Accomodation for near vision c. Reduce intraocular pressure: as when the pupil is constricted, the anterior chamber angle is widened and this facilitates the drainage through Canal of Schlemm

PARASYMOATHOMIMETICS

INCLUDES

CHOLINESTERS

CHOLINOMIMETIC ALKALOIDS

ANTICHOLINESTERASES

CHOLINESTERS1. Carbachol 1% 2. Bethenecol 1%

CHOLINOMIMETIC ALKALOIDSPilocarpine 2%

ANTICHOLINESTERASES

INCLUDESREVERSIBLE PHYSOSTIGMINE 1% NEOSTIGMINE 3% IRREVESIBLE AS D.F.P 0.1%

PARASYMATHOMIMETICS

PUPIL SIZE: MIOSIS LIGHT REFLEX: ABSENT ACCOMODATION: FOR NEAR VISION IOP: REDUCED CONJUNCTIVAL BV: CONGESTED

MYDRIATICSCAUSE

PASSIVE MYDRIASIS

ACTIVE MYDRIASIS

PARASYMPATHO LYTICS

SYMPATHOMIMETICS

COCAINE

PARASYMPATHOLYTICSMECHANISM OF ACTIONThey cause paralysis of sphincter pupillae muscle leading to: a. Passive mydriasis b. Abolish light reflex c. Increase IOP: due to narrowing of anterior chamber angle d. Loss of accomodation for near vision: as they produce cycloplegia

PARASYMPATHOLYTICSINCLUDES

ATROPINE 1%LAST FOR 10 DAYS

ATROPINE SUBSTITUTES

HOMATROPINE 2% FOR 24 hrs EUCATROPINE 2% 3-4hrs

CYCLOPENTOLATE 1% 2hrs TROPICAMIDE1%

THERAPUTIC USES1. Fundus examination and diagnosis of refractory errors 2. To break recent adhesions between the iris and the lense in anterior uveitis 3. Treatment of acute iritis and iridocyclitis as they relief pain resulting from cilliary muscle spasm

PAEASYMPATHOLYTICS PUPIL SIZE: PASSIVE MYDRIASIS LIGHT REFLEX: ABSENT DUE TO PARALYSISOF CONSTRICTOR PUPILLAE MUSCLE ACCOMODATION: FOR FAR VISION IOP: INCREASED CONJUNCTIVAL BV: NO EFFECT

SYMPATHOMIMETICSMECHANISM OF ACTIONThey produce active mydriasis by sympathetic nerve fibers that are motor to radial muscle through action on 1 receptor They do not affect light reflex or accomodation They are vasoconstrictors so the reduce vascular congestion of conjunctival blood vessels

EXAMPLEEphedrine sulphate, Phenylephrine and Dipivefrin

COCAINEMECHANISM OF ACTION1.It produces active mydriasis as it potentiates sympathetic response by: a. Decreasing re-uptake of released recatecholamines b. Inhibits degradation of catecholamines by MAO 2. It preserves light reflex 3. Abolishes corneal reflex by its local anaesthetic action

CONJUNCTIVITISINCLUDES

BACTERIAL CONJUNCTIVITIS

ALLERGIC CONJUNCTIVITIS

BACTERIAL CONJUNCTIVITIS DEFINITIONIT IS INFLAMMATION OF THE CONJUNCTIVA ASSOCIATED WITH MUCOPURULENT DISCHARGE, REDNESS AND EYELIDS EDEMA

MANAGEMENTINCLUDES

EYE LOTIONS

HOT FOMENTS

ASTRINGENT EYE DROPS

TOPICAL ANTIMICROBIAL AGENTS

EYE LOTIONSTo wash off the discharge Example: Bland eye lotions Boric acid lotion 4%

HOT FOMENTSAre applied locally in order to relief edema and pain

ASTRINGENT EYE DROPSPrecipitate proteins so decrease capillary permeability Example: Zinc sulphate 1%

TOPICAL ANTIMICROBIAL AGENTSLocal eye drops every 1-2hrslday and eye ointment at night Example: Neomycin

ALLERGIC CONJUNCTIVITISDEFINITIONIT IS ACUTE ALLERGY DUE TO EXPOSURE TO ALLERGEN . THE PATIENT PRESENT WITH REDNESS OF EYES WITH ITCHING AND LACRIMATION

MANGEMENTINCLUDES

TREATMENT OF ACUTE ATTACK

PROPHYLACTIC TREATMENT

ANTI-HISTAMINIC EYE DROPS

GLUCOCORTICOID EYE DROPS

MAST CELL STABILIZERS

ANTI-HISTAMINIC EYE DROPSExample: Levocabastine Antazoline

GLUCOCORTECOIDS EYE DROPSExample: Dexamethasone Precaution: We must exclude viral dendritic ulcer and glaucoma

MAST CELL STABILIZERSExample: Na cromoglycate

GLAUCOMADEFINITIONIT IS AGROUP OF DISEASES THAT HAVE IN COMMON A CHARACTERISTIC OPTIC NEUROPATHY WITH ASSOCIATED VISUAL FIELD LOSS FOR WHICH THE ELEVATED INTRAOCULAR PRESSURE IS ONE OF PRIMARY RISK FACTORS

CLASSIFICATION

INCLUDES

CLOSED-ANGLE GLAUCOMA

OPEN-ANGLE GLAUCOMA

CLOSED-ANGLE GLAUCOMA

It is associated with a shallow anterior chamber, in which a dilated iris can occlude the outflow drainage pathway at the angle between cornea and cilliary body In this type, acute and painful rise of IOP is often precipitated that must be controlled on an emergency basis with drugs or prevented by iridectomy

OPEN-ANGLE GLAUCOMA

The outflow of aqueous humour through the trabecular meshworkmeshworkSchlemm Schlemms canal venous system is impaired It is a chronic condition and treated medically, aiming to slow the rate of disease progression to prevent significant visual impairment

MEDICAL MANAGEMENT OF GLAUCOMAINCLUDES

-BLOCKERS

DIURETICS

SYMPATHOMIMETICS

PROSTAGLANDIN ANALOGUES

PARASYMPATHOMIMETICS

- BLOCKERSMECHANISM OF ACTION INCLUDESTimolol blocks beta receptors on the cilliary processes resulting in decreasing aqueous SELECTIVE 1 NON-SELECTIVE production It is treatment of choice in open-angle BLOCKERS BLOCKER glaucoma TIMOLOL MALEATE TOPICAL EYE DROPS LEVOBUNOLOL HCL TOPICAL EYE DROPS

DIURETICSINCLUDES

HYPER CARBONIC OSMOTIC inhibit carbonic anhydrase in the ANHYDRASE They by withdrawing fluid from the eye It acts AGENTS INHIBITORS

MECHANISM OF ACTION OF MECHANISM OF ACTION OF CARBONIC ANHYDRASE AGENTS HYPEROSMOTIC INHIBITORScilliary body, which prevents bicarbonate and reducing vitreous volume synthesis resulting in a fall in Na transport and aqueous flow ACETAZOLAMIDEORAL I.V IN EMERGENCY

MANNITOL I.V

DORZOLAMIDE TOPICAL EYE DRPS

SYMPATHOMIMETICSINCLUDES MECHANISM OF ACTION OF AND AGONISTS MECHANISM OF ACTION OF 2 It lowers the IOPAGONIST between and by a balance adrenoreceptors stimulation AND 1. mediated VC of the cilliary BVs will 2 AGONIST 1. It reduces aqueous humour production AGONISTS Decrease the aqueous flow

2. It increases uveoscleral outflow (secondary 2. 2 mediated effect will increase pathway for aqueous outflow 20%) trabecular meshwork drainage

CONTRAINDICATIONTARTRATE DIPIVEFRIN HCL BRIMONIDINE TOPICAL EYE DROPS TOPICAL EYE Angle-closed glaucoma DROPS

PROSTAGLANDIN ANALOGUES (F2 )EXAMPLE AND FORMLatanoprost solution: topical eye drops

MECHANISM OF ACTION1. It enhances the uveoscleral outflow of the aqueous 2. It increases blood flow to the optic nerve that may contribute in retinal neuroprotection

PARASYMPATHOMIMETICSEXAMPLE AND FORMPilocarpine HCL: topical eye drops or gel

MECHANISM OF ACTIONIt increases aqueous outflow by contracting the ciliary muscle. Which pulls the scleral spur, resulting in widening of the trabecular meshwork

SIDE EFFECTSBlurred vision and ache over the eye

DRUGS CONTRAINDICATED IN GLAUCOMATopical and systemic corticosteroids due to the possible increase in trabecular meshwork inducible glucocorticoid response (TIGR) gene expression as an assumed mechanism for outflow obstruction Strong vasodilators as nitrites as they may Increase aqueous humour formation Cycloplegic drugs as atropine