pharmacology of the eye prepared by: dr./ rehab lashine pharmacology department
TRANSCRIPT
PHARMACOLOGY OF THE EYE
Prepared By :
Dr./ Rehab LashinePharmacology Department
Physiological Anatomy of the Eye
THE ANT.CHAMBER OF THE EYE
The Ciliary Body
The Pupil
Pupillary Muscles
Mydriasis
Miosis
Effect of Miosis and Mydriasis on Acquous Humor Drainage
Accomodation
Autonomic Nerve supply of the Eye
Parasympathetic:
1- Bl.Vs. …Conjuctival VD ( Oculomotor)
2- Ciliary mm.. (Accomodation) (Oculomotor)
3- Sphincter pupillae(Miosis) (Oculomotor)
4- Increased lacrimation…..7th vranial n.(N.B.: Stim. Of the nic. Rec. causes twitches of
eye lid mm.)
•Sympathetic1- Bl.Vs.( Conjunctival VC)………α1
2- Dilator Pupillae ( Mydriasis)…….. α1
3- Levator palpebrae & Muller’s m.(Exophthalmus & widening of the palpebral fissure)…..
4- Ciliary mm (relaxation)……. β2
5- Lacrimal glands (lacrimation)……… α1
6- α & β rec. in the Bl.vs. of the ciliary processes….help in regulation of aqueous humour formation
Light Reflex
Corneal Reflex
Drugs Acting on the Eye
I- Drugs affecting the size of the pupil:MioticsMydriatics
II- Drugs Affecting Accomodation….Cycloplegics
III- Drugs affecting the IOP (intraocular pressure)
IV- Local Anesthetics
V- Antiallergic agents
VI- TTT of Eye Infection
Miotics
M3 rec.: Parasympathomimeticsα1 blockers:
Sympatholytics(e.g.Phenoxybenzamine)
Central : Morphine ( ↑oculomotor nucleus)
USES:-Glaucoma-Counteract action of mydriasis- To break adhesions
Mydriatics Active:
- Sympathomimetics….(Mydriasis without Cycloplegia or loss of light reflex)
- Local anesthetics…..(Cocaine) (Mydriasis without Cycloplegia or loss of light reflex ).
Passive: - Anticholinergics……(Mydriasis with Cycloplegia & loss of light
reflex) except Eucatropine (doesn’t cause cycloplegia).
Ganglion Blockers …...(Mydriasis with Cycloplegia ) Central
USES:Fundus Exam, Therapy of acute Iritis, Breaking Adhesions
Drugs Affecting Accomodation
Drugs causing Accomodation to near objects:
- stim. of ciliary mm: Parasympathomimetics
Cycloplegics: drugs causing paralysis of ciliary mm…..loss of accomodation…fixation of vision for far vision: Parasympatholytics (EXCEPT EUCATROPINE)
N.B:.Sympathomimetic mydriatics are safely
used in adults > 40 years in whom Atropine have the risk of causing dangerous rise in IOP.
Therapeutic uses of Cycloplegic drugs:1- Ttt of Iridicyclitis2- Ttt of choroiditis3- Measurement of refractive errors
Drug Therapy of Primary Open Angle (chronic simple) Glaucoma
A) Miotics: They act mainly by↑ the acqueous outflow.
1- Direct : pilocarpine.
2- Indirect: choline esterase inhibitors
B) Sympathomimetics: ↓ acq.humour production, & ↑ outflow
C) Β-adrenoceptor blocking agents: ↓ acq.humour production…….Timolol, befunolol
D) Oral Agents: Carbonic Anhydrase inhibitors. ↓ acq.humour production…..Acetazolamide
Drug Therapy of acute angle closed (congestive) glaucoma
Dehydrating agents: IV infusion Of Hypertonic solution ( Mannitol, Glycerol)
Oral Acetazolamide
Topical miotics: e.g.: pilocarpine
Analgesics: pethidine or morphine (for pain)
Drug used in treating inflammatory and allergic eye conditions
1- Conjunctivitis: can be ttted by:A- Penicillin G, chloramphenicol ( Acute purulent
conj.)
B- Sulphacetamide (eye drops)..for trachoma
C- Tetracycline ….for chronic follicular conjunctivitis
D- Vidarabine, or Acyclovir for Herpes simplex keratitis
E- Topical steroids for chronis puppillary conj.
Drug used in treating inflammatory and allergic eye conditions( Cont.)
2- Glucocorticoids: to suppress inf., and allergy
3- Topical Antihistaminics: (eye drops), in allergies
4- Sodium cromoglycate: ( for ttt. Of spring catarrh, vernal keratoconjunctivitis)
5- Astringents : Zinc Sulphate ( angular conj.)
Harmful drugs for the Eye1- Drugs that ↑ IOP: A- Mydriatic cycloplegics, tricyclic antidepressants B- Chronic steroid use
2- Cataractogenic drugs: steroids, phenothiazines, heavy metals…
3- Drug-induced retionopathies: ethanol, methano, indomethacin,steroids
4- Drugs causing corneal deposits: Amiodarone, chloroquine…
5- Oculomucocutaneous syndrome ( Conj. Fibrosis, corneal opacities,and dimnished tear secretion) e practolol
6- O2 : 40 % for prolonged periods in premature infants causes Retrolental fiboplasia
Experiment