Glaucoma

group of ocular disorders characterized by changes in optic disk (optic nerve) that lead to optic neuropathy associated with visual sensitivity and field loss

• age >40
• family hx (20% chance of developing if an immediate relative has)
• african american/asian decent
• diabetes
• long-term steroid use
• previous eye injury

• open angle (60-70%)
• closed angle (rare)

ciliary body

blood pressure and intra-ocular pressure

• carbonic anhydrase
• alpha and beta receptors
• Na/K ATPases

2-3 microliters/min

• through the trabecular meshwork into the schlemm's canal (80-85%) then to the blood stream
• uveoscleral outflow: absorption into the iris blood vessels

10-20 mmHg

• pulse
• blood pressure
• coughing
• neck compression
• posture

• min- 6 pm
• max- awakening

balance between fluid production and outflow

decreased aqueous humor outflow through the trabecular meshwork

increased pressure from aqueous humor puts pressure on the vitreous humor (behind the lens) which puts pressure on the optic nerve which may lead to blindness

• second leading cause of blindness
• chronic, slow progressing generally gound in pts >50
• usually bilateral but one eye may be more affected than the other
• angle between the cornea and iris remains open

• systemic diseases, trauma, surgery, lens changes, inflammatory diseases,
• drugs: corticosteroids, anticholinergics, vasodilators

• loss of peripheral vision but may be diagnosed before this is seen
• sensitivity to glare
• trouble differentiating shades of light
• may have an increase in IOP but not necessaryily for diagnosis

• comprehensive eye exams
• patients <45: no risk factors (every 4 yrs) with risk factors (every 2 yrs)
• patients >45: no risk factors (every 2 yrs) with risk factors (every yr)

• further visual field loss reduced by lowering IOP to <10-12 mmHg
• progression to bilarteral blindness: 4-22% of patients
• 60-80% of patients can have their IOP controlled with drug therapy over a 5 yr period

• patients with possible glaucoma (IOP >22 mmHg)
• don't treat, just watch and wait

aqueous humor production- decreased

aqueous humor production- decreased

• trabecular outflow- increased ??
• uveoscleral outflow- increased

• aqueous humor production- increased/decreased
• trabecular outflow- increased
• oveoscleral outflow- increased

• aqueous humor production- decreased
• uveoscleral outflow- increased???

• used to shrink part of the meshwork
• minutes to perform under local anethesia
• improves drainage of aqueous fluid and reduces IOP
• Complications: cataracts, inflammation, hemorrhage, chronic, macular edema
• typically used when drug therapy fails, is not tolerated, or becomes too complicated

• creates new drainage pathway
• 5-FU and mitomycin used to here to improved success rates by reducing the inflammatory response
• drainage implants: small silicon tube inserted into the eye to help with drainage
• typically considered when drug therapy fails

• agent of choice
• lower incidence of local adverse effects
• precautions: pulmonary disease, bradycardia, 2nd or 3rd degree heart block, CHF, diabetes, myasthenia gravis, pt receiving oral beta blocker therapy
• Side effects: stinging, dry eyes, corneal anesthesia, blepharitis, blurred vision, decreased heart rate, reduced blood pressure, block symptoms of hypoglycemia

• timolol
• levobunolol
• metipranolol

• betaxolol
• levobetaxolol

carteolol

• sulfa allergies
• sickle-cell anemia
• respiratory acidosis
• pulmonary disorders
• renal disease
• diabetes
• hepatic disease

• transient burning and stinging
• ocular discomfort
• blurred vision
• tearing
• every 12 hours administration produces less IOP reduction than every 8 hour dosing

• malaise
• fatigue
• systemic acidosis
• anorexia
• nausea
• weight loss
• depression
• altered taste
• decreased libido
• increased uric acid
• renal stones

• acetazolamide
• methazolamide
• dorzolamide (trusopt)
• brinzolamide (azopt)

last line drugs, due to ocular and systematic toxic effects

• similar to miotics
• fibrinous iritis
• iris cysts
• conjunctival thickening
• occlusion of the nasolacrimal ducts
• cataracts

• asthma
• retinal detachments
• narrow angle glaucoma
• bradycardia
• hypotension
• HF
• seizures

• pilocarpine
• ***patients with dark pigmented eyes may require higher concentrations of pilocarpine***

• decreases in night vision
• frontal headaches
• eyelid twitching
• irritation

• diaphoresis
• N/V
• diarrhea
• caramping
• urinary frequencing
• bronchospansm
• heart block

• carbachol (Isopto carbachol)
• pilocarpine

• drugs are more effective given at night than during the day
• maybe useful as first-line therapy in patients who cannot tolerate or have C/I with beta-blockers

• uveitis
• changes in iris pigmentation
• hypertrichosis
• increased pigmentation in eyelashes
• ***color changes may be permanent and may takes months or years to become noticeable***

• latanoprost (Xalatan)
• travoprost (Travatan)
• unoprostone (Rescula)
• brimaprost (Lumigan)

• cardiovascular disease
• cerebrovascular diseases
• closed-angle glaucoma
• hyperthyroidism
• diabetes

• tearing
• burning
• ocular discomfort
• browache
• loss of eyelashes
• blurred vision

• increased blood pressure
• tachycardia
• arrhythmias
• tremor
• pallor
• anxiety
• increased perspiration

• diplvefrin (Propine)
• epinephryl borate (Epinal)
• epinephrine (glaucon)

• structurally similar to clonidine
• apraclonidine is less used due to tachyphylaxis and more severe allergy rates
• precautions: cardiovascular disease
• renal disease
• cerebrovascular disease
• diabetes
• patients taking MAOIs, TCAs, or antihypertensives

• ***usually a sign of allergic reaction and need to discontinue agent***
• lid edema
• eye discomfort
• foreign-object sensation
• itching
• systemic side effects: dizziness, somnolence, dry mouth, reduction in blood pressure and pulse

• apraclonidine (Iopidine)
• brimonidine (Alphagan)

• medical emergency
• less than 5% of glaucomas
• due to mechanical blockage of the aqueous humor outflow (closure of the angle) blockage usually by the peripheral iris
• symptoms: pain, vomiting, blurred vision, halos around lights, reddening of the affected eye, swollen or cloudy corneas, IOP >40 mmHg
• GOAL= rapid reduction of IOP, avoid surgery

• pilocarpine
• beta-blocker
• alpha-2-agonists
• prostaglandin analogs
• carbonic anhydrase inhibitors
• the opposite eye should be treated as well