GLAUCOMA Flashcards
Glaucoma
Optic neuropathies characterized by progressive degeneration of retinal ganglion cells
Types of glaucoma
Open angle glaucoma (OAG)
Closed angle glaucoma (CAG)
Most common form of glaucoma
Primary open angle glaucoma
Primary OAG is rare in people under
50 years
Most visually destructive form of glaucoma
Closed angle glaucoma
Which form of glaucoma is a medical emergency
Closed angle glaucoma
Glaucomatours optic neuropathy
Damage and remodeling of the optic disc tissues and lamina cribosa that lead to vision loss.
POAG prevalence is highest in which population
Older Hispanic or Latino> Blacks> Whites>Asians
Causes of glaucoma
Congenital
Trauma
Type 2 DM
Pigmentary dispersion sundrome
Raised intraocular pressure
Prolonged corticosteroid use
Hereditary
Pigmentary dispersion syndrome
Pigment cells slough off from the back of the iris and float around in the aqueous humor
What type of glaucoma is caused by pigmentary dispersion syndrome
Pigmentary glaucoma
Distribution of glaucoma according to sex
Males>Females
Risk factors for glaucoma
Age
Family history
Black race
Use of systemic or topical corticosteroids
High intraocular pressure
Genetics
Which cells produce the aqueous humor
Ciliary body
Rate of production of aqueous humor
2.5mcl per minute
Flow of aqueous humor
Ciliary body secretes into the Posterior chamber
flows to Anterior chamber through the pupil
flows to the trabecular meshwork in the anterior angle
Pathways for drainage of the aqueous humor
Schlemm’s canal (from trabecular network)
Uveoscleral pathway
Driving force for the uveoscleral outflow pathyway
Pressure gradient created by movement of the ciliary muscle
Trabecular meshwork structure
Collagen and elastic tissue covered by trabecular cells that form a filter
Intraocular pressure is determined by
Balance between aqueous humor production and drainage through the trabecular meshwork and uveoscleral outflow pathway.
Effect of high IOP on mitochondrion
Mitochondrial dysfunction which leads to metabolic stress and nerve degeneration
Lamina cribosa
Mesh-like structure in a hole in the sclera where the optic disc exits the eye
Role of lamina cribosa
Maintains the pressure gradient between the inside of the eye and the surrounding tissues
Effect of high IOP on the lamina cribosa
Displaces the lamina cribosa
Displacement of the lamina cribosa leads to……..
Pinching of the optic nerve and blood vessels causing nerve damage
Normal IOP
15-16mmHG, SD of 3mmHg
Ocular hypertension
IOP above 21mmHg
Types of open angle glaucoma
Primay
Secondary
Examples of open angle glaucoma
Juvenile glaucoma
Drug-induced
Low tension/normal tension
Pseudo-exfoliating
Pigmentary
Inflammatory
Examples of closed angle glaucoma
Malaignant glaucoma
Hyphema glaucoma
Juvenile glaucoma
Diagnostic investigations in glaucoma
Ophthalmoscopy
Tonometry
Gonioscopy
Fundoscopy
Visual function test
pectral-domain optical coherence tomograph
Spectral-domain optical coherence tomography
provides high-resolution, optical cross-sectional analysis of the retina, and choroid with depth-resolved segmentation
TONOMETRY
A test to measure the pressure inside the eye
GONIOSCOPY
uses a special lens and slit lamp to evaluate your eye’s drainage angle (anterior chamber angle)
FUNDOSCOPY
Examination of the fundus of the eye using a magnifying lens and light
Fundus
Back surface of the eye made up of
Retina
Optic disc
Fovea
Blood vessels
VISUAL FUNCTION TEST
to detect changes in peripheral vision
Signs and symtopms of chronic open angle glaucoma
40 yrs and above
Normal cornea
Symptoms are nill till late then progressive visual loss
IOP is usually high but may be normal
Signs and symtoms of acute angle closure glaucoma
Elderly
Sudden visual loss
Severe eye pain
Very inflamed eye
Watery discharge
Headache
Halos around light
Very high IOP
Hazy cornea
Signs and symptoms of congenital open angle glaucoma
Infants and toddlers
Photophobia
Watering
High IOP
Enlarged and hazy cornea with linear breaks
Target range of IOP
10-20mmHg
Two classes of non-pharmacological options for glaucoma
Penetrating/Incisional surgeries
Non-penetrating surgeries
Penetrating/Incisional surgeries
Trabeculectomy
Aqueous shunt
Combined surgeries
Non-penetrating surgeries
Deep Sclerectomy
Viscocanalostomy
Canaloplasty
Laser trabeculoplasty
Laser peripheral iridoctomy
Types of laser trabeculoplasty
Argon and diode laser trabeculoplasty
Selective laser trabeculoplasty
Trabeculectomy
Creating a new path in the eye for drainage
Deep sclerectomy
Removal of a deep scleral flap to create a scleral space for drainage
Drug classes used in glaucoma
Prostaglandin analogues
Beta antagonists
Alpha agonists
Parasympathomimetics
Carbonic anhydrase inhibitors
Rho kinase inhibitors
NMDA antagonists
MOA of prostaglandin analogues in glaucoma
Increase uveoscleral outflow
Induction of MMP in ciliary body
Role of Matrix metallopeoteinases (MMP)
Breaks down extracellular matrix, reducing resistance to outflow through the uveoscleral pathway
Recommended first line for Primary open angle glaucoma
Prostaglandin analogues
XALATAN
Latanaprost
SAFLUTAN
Tafluprost
TRAVATAN
Travoprost
LUMIGAN
Bimatoprost
Prostaglandin analogues
Bimatoprost
Travoprost
Tafluprost
Latanaprost
Latanoprostene bunod ophthalmic
MOA of beta antagonists
Decrease aqueous humor production by ciliary body
Recommended first line for patients who cannot tolerate prostaglandind analogues
Beta adrenergic antagonists
Contraindications of beta antagonists
Bradycardia
Heart block
BETOPTIC
Betaxolol
CUSIMOLOL
Timolol
BETAGAN
Levobunolol
Beta adrenergic antagonists
Nonselective:
Carteolol
Levobunolol
Metipranolol
Timolol
Selective:
Betaxolol
MOA of alpha-2 agonists
Decreases aqueous humor production
Increases uveoscleral outlfow
ALPHAGAN
Brimonidine
Alpha-2 adrenoceptor agonists
Brimonidine
Apraclonidine
Contraindications of alpha-2 agonists
Unstable cardiovascular disease
…………………………………. is used to control IOP after anterior segment laser surgery
Apraclonidine
Ocular adverse effects of alpha-2 agonists
Allergic or follicular conjunctivitis
Contact dermatitis
Systemic adverse effects of alpgha-2 agonists
Dry mouth
Fatigue
Drowsiness
Hypotension
MOA of parasympathomimetics
Opens inefficient drainage channels in the trabecular meshwork
Contraindications to parasympathomimetics
Acute iritis
Anterioir uveities
When pupillary constriction is undesirable
Parasympatho mimetics
Pilocarpine- cholinergic agonist
Ecothiophate-anticholinesterase
Carbonic anhydrase inhibitors
Reduces bicarbonate ions production and fluid flow in the ciliary body
Reduces production of aqueous humor
Contraindications to carbonic anhydrase inhibitors
Adrenocortical insufficiency
Hypokalemia
Hyponatremia
Metabolic acidosis
AZOPT
Brinzolamide
TRUSOPT
Dorzolamide
DIAMOX
Acetazolamide
CA inhibitors
TOPICAL
Brinzolamide
Dorzolamide
ORAL
Acetazolamide
Methazolamide
……………… and ………….. is preferred for long term treatment of primary open angle glaucoma
Brinzolamide
Dorzolamide
AZARGA
Brinzolamide
Timolol
SIMBRINZA
Brinzolamide
Brimonidine
COSOPT
Timolol
Dorzolamide
Rho kinase inhibitor
Increase aqueous outflow tthrough trabecular meshwork
indications of rho kinase inhibitor
Open angle glaucoma
Ocular hypertension
RHOPRESSA
Netarsudil
Side effects of rho-kinase inhibitors include
Hyperaemia
Conjunctival Haemorrhage
Excitotoxicity
cells die via apoptosis because of the presence of excessive amounts of glutamate
NMDA antagonist
Memantine
NAMENDA
Memantine
NMDA antagonist role in glaucoma management
Protection of neurons chiefly the retinal ganglion cells axons from excitotoxicity