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1

Glaucoma

chronic progressive ocular disease that toleads to progressive damage to the optic nerve and subsequent loss of visual field

major risk factor: increased IOP

2

Classification of Glaucoma

Based on Etiology

  • Primary: open angle closure, congential
  • Secondary: due to other ocular or systemic disease (inflammatory or lens induced glaucoma)

 

Based on Mechanism

  • open angle glaucoma
  • angle closure glaucoma

3

What is normal intraocular pressure?

10 to 21 mm Hg

4

Pathophysiology of IOP causing Optic Nerve damage

Mechanical Compression of Optic Nerve

Obstruction of blood supply and death of nerve fibers - causes hollowing of the optic nerve (cupping)

5

Eye Examination for Glaucoma

Check Vision

Refraction

Pupils (RAPD)

Measure IOP (Applanation, Tonopen, Schiotz, Pneumatonometer or palpation)

Gonioscopy

Examine Optic Nerve

Perimetry and Visual Fields - can do confrontation testing, or Humphrey Field Analyzer or Goldmen Perimetry

Imaging

6

ISNT Rule

"if it isn't ISNT then it isn't"

Rim width - distance between border of disc and position of blood vessel bending

Inferior > Superior > Nasal > Temporal

7

Characteristic Field Defects

Arcuate Defects

Nasal Step

Paracentral Defect

Annular Scotomas

Temporal Wedge

Tunnel Vision with temporal Island

Enlargment of Blind Spot

8

ACUTE VISION LOSS - - - REFER IMMEDIATELY

Acute Glaucoma

Keratitis

Endophthalmitis

Vitreous or Retinal Hemorrhage

Retinal Detachment

Acute Maculopathy

Retinal Vessel Occlusions

Optic Neuritis

Ischemic Optic Neuropathy

Cortical Infart

9

CHRONIC VISION LOSS - - - REFER NON-URGENTLY

Refractive Error

Media Disturbances in the tear film, cornea, lens or vitreous

Lesions of the nueral visual pathway from the retina to the visual cortex

10

Open Angle Glaucoma

usually no symptoms

identified on routine eye exams

some patients compalin of decreased peripheral vision

prognosis: depends on stage at time of diagnosis and ability to reduce and manage IOP

11

Managment of Chronic Glaucoma

establish a baseline

set a reasonable goal for IOP

lower the pressure

continue to observe patient, modifiy if necessary

12

Prostoglandin Analogs for Glaucoma

Xalatan, Travatan, Lumigan

  • increase uveo-scleral outflow, reducing IOP
  • administered once a day

13

ß Adgrenergic Antagonists

Timpotic, Betoptic S, Betagan

  • reduces the production of aqueous humor by inhibiting cAMP, reduces IOP
  • adminstered 1-2x a day

 

  • side effects: corneal anesthesis, ptosis, hypotony, burining, superficial punctate keratitis, dry eye
  • systemic: psychosis, fatigue, BRADYCARDIA, syncope, alopecia, nausea, impotence, ASTHMA, altered response to hypoglycemia, heart failure, tinnitus, depression, anxiety, hallucinations, dysarthria, CVA

14

Sympathomimetics

Epinephrine, Dipivefrin (Propine)

  • reduces aqueous humor production, increases outflow through trabecular meshwork
  • twice a day
  • side effects: local irritation, pigmentation, corenal damage, macular edema, HTN, cardiac failure

Alpha Agonists: Iopidine, Alphagan

  • reduce production of aqueous humor, possibly increases outflow
  • 3x a day
  • side effects: local allergy, dry nose and mouth, fatigue, trachyphylaxis

15

Parasympathomimetrics

Pilocarpine, Carbachol, Echothiophate

  • increases outflow facility, reduces IOP
  • 2x a day for echo, 4x a day for pilo
  • side effects: browache, headache, occular allergy, pupillary constriction, RD, ocular inflammation
  • parasympathetic effects

16

Carbonic Anydrase Inhibitors

Topical: Drozolamide (Trusopt), Brinzolamide (Azopt) - twice a day

Oral/Parenteral: Acetazolamide (Diamox), Methazolamide (Neptazane) - 2-4 x a day

  • reduces production of aqueous humor by inhibiting carbonic anydrase
  • side effects: fatigue, parestheisas, metallic taste, electrolyte imbalance, acidosis, kidney stones, cardiovascualr and respiratory depressions, topical drops may cause local allergy

17

Hyperosmotic Agents

Oral: Glyercol, Isosorbide

IV: Mannitol

  • reduce vitreous volume to lower IOP
  • rapid effect to lower pressure within minutes
  • side effects: nausea, vomiting, diuresis, cardiovascular overload, hyperglycemia in diabetics

18

Current Medical Treatments to Lower IOP

  1. Prostaglandin
  2. ß-Adrenergic Antagonists (ß-Blockers)
  3. Adrenergic Agonists (Sympathomimetrics)
  4. Carbonic Anhydrase Inhibitors
  5. Cholinergic Agonists (miotics)

19

Surgical Treatments of Glaucoma

Laser - iridectomy

Trabeculectomy - guarded opening in the sclera

Glaucoma Drainage Device

20

Describe the presentation of congenital glaucoma:

• Epiphora – watering eyes
• Photophobia
• Blepharospasm
• Buphthalmos – enlargement of the eye
• Haab’s Striae - Horizontal breaks in Descemet's membrane