GLAUCOMA AND ANTI- GLAUCOMA

DRUGS

GLAUCOMA

A disease of progressive optic neuropathy

with loss of retinal neurons and the

nerve fiber layer, resulting in blindness if

left untreated.

There is a dose-response There is a dose-response relationship between intraocular relationship between intraocular pressure and the risk of damage pressure and the risk of damage to the visual field.to the visual field.

What causes it?What causes it?

The IOP refers to the pressure exerted by

the intraocular fluids on the coats of the

eyeball

Normal IOP is 10-21mm Hg (mean

16±2.5mmHg)

Angle AnatomyAngle Anatomy

AQUEOUS AND ANATOMY

Aqueous is continuously produced by the ciliary body

Aqueous flows from the posterior chamber through the pupil into the anterior chamber

Aqueous filters largely through the trabecular meshwork (90%)

Aqueous also exits to a smaller extent through the ocular venous system (10%)Uveoscleral outflow (ciliary body, choroid, scleral

vessels)

Types of glaucoma

I. Primary: A. Congenital B. Hereditary C. Adult (common types) 1. Narrow angle 2. Open angle II. Secondary A. Inflammatory B. Traumatic C.Phacolytic etc.

Congenital Glaucoma

Onset: antenatally to 2 years old

SymptomsSymptoms

IrritabilityIrritability PhotophobiaPhotophobia Poor visionPoor vision

Signs Elevated IOP Buphthalmos Corneal clouding Glaucomatous cupping Field loss

Congenital Glaucoma

Buphthalmos and cloudy corneasBuphthalmos and cloudy corneas

Congenital Glaucoma

Buphthalmos, glaucomatous cupping, and cloudy cornea OD

Haab’s striae

Narrow Angle GlaucomaOnset: 50+ years of ageOnset: 50+ years of age

SymptomsSymptoms Severe eye/headacheSevere eye/headache painpain Blurred visionBlurred vision Red eyeRed eye Nausea and vomitingNausea and vomiting Halos around lightsHalos around lights Intermittent eye acheIntermittent eye ache at nightat night

SignsSigns Red, teary eyeRed, teary eye Corneal edemaCorneal edema Closed angleClosed angle Shallow ACShallow AC Mid-dilated, fixedMid-dilated, fixed pupilpupil Iris atrophyIris atrophy AC inflammationAC inflammation

Narrow Angle GlaucomaMid-dilated, fixed pupilMid-dilated, fixed pupil

Open Angle Glaucoma

Onset: 50+ years of ageOnset: 50+ years of age

SymptomsSymptoms Usually noneUsually none May have loss of central May have loss of central and peripheral visionand peripheral vision latelate

SignsSigns Elevated IOPElevated IOP Visual field lossVisual field loss Glaucomatous disk changesGlaucomatous disk changes

Open Angle Glaucoma

HISTORY:Positive family historyAfrican American backgroundHistory of traumaHistory of steroid use

Risk factorsRisk factors

Parasympathetic Innervations to the Eye

2/19/201015

2/19/201016

AUTONOMIC NERVOUS SYSTEMSympathetic regulation

Fight and flight 2 main classes of receptors

Beta receptors (ß1 and ß2)Alpha receptors (α1 and α2)

Parasympathetic regulation

AUTONOMIC NERVOUS SYSTEMPupil is controlled by both

Sympathetic system dilates the pupil by stimulating the contraction of dilator muscle

Parasympathetic system constricts the pupil by causing contraction of the sphincter muscle.

Ciliary body is controlled by bothSympathetic system for aqueous productionParasympathetic system causing ciliary body muscle movement

Drugs used in treatment of glaucomaDRUGS MOA DOSE REG.

Directly acting cholinomimetics

PILOCARPINE

1) Ciliary muscle contraction.2) Pupillary constriction3) Pulling of iris 4) Opening of Trabecular meshwork All causes increased drainage of aqueous humor and causes decrease in IOP

0.5 – 4% topically TDS

Reversible Anti- AchE

PHYSOSTIGMINE -DO- 0.25 – 5% topically TDS

Irreversible Anti- AchEEcothiophate

-DO- 0.05 – 0.25% topically once in 2 weeks

Beta- blockersa)Timololb)Butaxololc)Levovunolold)Carteolol

Reduce the aqueous humorFormation by blocking b2 receptorsPresent on ciliary epithelium

0.25 – 5% BD

NONSELECTIVE α agonist1)Epinephrine2)dipivefrine

Facilitate outflow of Aqueous Humour Better penetration through cornea’ longer duration of action

0.15 – 0.25% topically 0.1%-tds

SELECTIVE α2 Agonist1)APRACLONIDINE2)BRIMONIDINE

Reduce the formation of aqueous Humour .do not cross blood brain barrier. Hence no systemic effects.

0.5 to 1% topically 0.2%topically .use restricted for acute rise in IOP after laser trabeculoplasty

Prostaglandin F2 α

analogues

Latanoprost

bimatoprost

Increase fluid

outflow through

ocular venous system

(uveoscleral outflow0.005% OD

Carbonic Anhydrase inhibitors Acetazolamide Dorzolamide

Reduces AH formation by decreasing the formation of HCO3 ion in ciliary epithelium

250-500 mg 3 times daily 1% sol BD

Prostaglandins

Systemic side effects are extremely rareAllergy is extremely rareMost side effects are local and cosmetic

Conjunctival hyperemiaIris pigmentationPeriorbital darkeningEyelash growth/thickening/darkening

WHEN PROSTAGLANDINS ARE YOUR FIRST CHOICE

Primary Open Angle GlaucomaOcular HypertensionPigmentary Glaucoma