b9 - glaucomas

• glaucoma

  • mostly about pressure - treatable bit of glaucoma
  • and the iridocorneal angle - controlling feature of glaucoma
  • open angle and closed angle
  • primary open angle glaucoma
  • normal tension glaucoma/ low tension glaucoma
  • pigment dispersion
  • PXF - pseudoexfoliation glaucoma
  • closed angle
  • secondary uveitic and trauma glaucoma
• regulation of glaucoma

  • ocular plumbing - production of aqueous fluid which maintains eye pressure and structure; eye continues to produce 3 micro meters per minute of aqeous regardless
  • the aqueous has to leave the eye otherwise the ball will explode
  • this is produced by cilliary epithelium and goes down trabecular meshwork and uveoscleral pathway
  • produce 6.6 pints of aquous per year between both eyes

  
• relationship of IOP to field loss

  • normal distribution for intraocular pressure
  • px with glaucoma have higher IOPs but dont need high pressure to generate glaucoma
  • can have glaucoma with normal IOP, can have pressure under 21mmHg and have glaucoma, can have pressure over 30mmHg and not have glaucoma
• risk factors for primary open angle glaucoma

  • elevative IOP
  • age - disease of aging visual system
  • black race
  • family history of glaucoma
  • myopia - weak eyes
  • migrane and vasospasm - controlling of blood flow to peripheries such as toes and fingers
  • if we constrict our perioheral digital arterioles then similar happens in optic nerve causing damage
• clinical focus on the optic nerve

  • 1.5mm high and area of 2 square millimeters 
  • Essentially a hole in the back of the eye 
  • Needs to be large enough to let retinal ganglion cell fibers signals to pass to the brain 
  • Has a central depression 
  • The RGC fibers line the inside of the whole which we call the rim 
  • Elschnig’s ring – demarcation of scleral boundary – not the edge of the optic disc, the end of the disc is marked by the end of Bruch’s membrane