1 / 49

Glaucoma

Glaucoma. Chapter 23. Role of Technician in Glaucoma . Case history Performing pretesting Aid in treatment Preoperative & postoperative care. Glaucoma . 76 million worldwide with glaucoma Many more undiagnosed! Elevated intraocular pressure Optic nerve cupping Visual field loss.

xerxes
Télécharger la présentation

Glaucoma

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Glaucoma Chapter 23

  2. Role of Technician in Glaucoma • Case history • Performing pretesting • Aid in treatment • Preoperative & postoperative care

  3. Glaucoma • 76 million worldwide with glaucoma • Many more undiagnosed! • Elevated intraocular pressure • Optic nerve cupping • Visual field loss

  4. Primary angle-closure glaucoma • ~10% of all glc patients • 5-10% of elderly population • More common in women because of shallower AC • Normal except anatomically have shallow angle

  5. Primary angle-closure glaucoma • Which of the following would have a more shallow angle because of typical eye anatomy associated with this condition? • Myopia • Hyperopia • Astigmatism

  6. Primary angle closure glaucoma • Crowding in the angle • Increases with age • Why? What structure inside the eye physically changes/grows with age? • Less than 20 degrees in width is said to constitute narrow angle glaucoma

  7. How does it happen? • Would dilation or constriction of the pupil cause more crowding in the angle? • What process can’t happen if there’s a bunch of iris tissue crowded into the angle?

  8. How does it happen? • Dilation causes the iris to “bunch up” in the angle • Aqueous humor cannot drain • Pressure builds up

  9. How does it happen • Usually begins in conditions that dilate the pupils • Can even happen because of dilation during an eye examination! • Medications could cause it • Can become fully developed in 30-60min

  10. Pain • This can be very painful • Patient may be nauseous and vomit • Cornea clouds up & patient cannot see

  11. Clinical Manifestations • Eyelid, conjunctiva, corneal edema • Cornea appears hazy & opaque • IOP is HIGH • Can be 50-60mm Hg or higher • Most people have had warning signs, but may not have understood them • Ache, blur, haloes, rainbows • Haloes usually inner blue-violet & outer yellow-red ring

  12. Diagnosis • Narrow angle identified in eye exam • Even though pressure may be normal at exam, definitely have to identify narrow angles! • Gonioscopy – the only true way to properly assess the narrowness of the angle

  13. Gonioscopy • Can differentiate between open-angle and narrow-angle glc • Types • Goniolens • Two to four-mirror lenses

  14. Gonioscopy

  15. What we see through a gonio lens • Ciliary body band • grayish • Scleral spur • White line • Trabecular meshwork • Pigmented • Schwalbe’s line

  16. Gonio view

  17. Treatment • Laser iridotomy • Do it bilaterally • 50-70% will have attack in other eye! • Allows AC to deepen

  18. Treatment • Must lower pressure first before attempting iridotomy

  19. POAG • Chronic, progressive, bilateral • Usually shows up after age 40, but diagnosed earlier now with our better screening methods • Usually caused by decreased outflow

  20. POAG • Diagnosis usually by results of three conditions • 1. increased IOP • 2. optic nerve cupping • 3. visual field defects

  21. Ocular Hypertension • Have high IOP but no VF or ONH changes • This means they can tolerate higher than normal IOP without damage • But they are a glaucoma suspect because of this, although most will never need meds to treat this

  22. Secondary Glaucoma • Caused by some other factor • Lens changes/dislocations • Scar tissue • Synechia • Iritis • Tumor • Trauma • Steroid use – chronic & high-dose

  23. Congenital Glaucoma • Rare • Infant may be very light sensitive and tear a lot • Corneal haziness & enlarged (buphthalmos)

  24. Tonometry • Measure of intraocular pressure • Many different ways

  25. Indentation (Schiotz) tonometry • Not used much anymore • Third world countries • Anesthetic • Rests on cornea & indents it • More indentation = softer cornea=lower IOP

  26. Applanation Tonometry • Cornea flattened • More accurate • The standard of measurement

  27. Goldmann Applanation Tonometry • Disadvantage-not portable • Need significant training to accurately perform • Anesthetic + fluorescein + blue light = green reflection

  28. Goldmann Applanation Tonometry See page 438 for incorrect flourescein bands

  29. IOP • Pressure varies during the day • Usually highest early am (diurnal variation)

  30. Perkins hand-held applanation tonometer • Same principle as Goldmann • It’s rather bulky

  31. Non-contact Tonometer • “Airpuff” • Principle of how long it takes the puff of air to exactly flatten cornea • Takes less time to flatten a soft eye (lower IOP) • Not as accurate • Can use with contact lenses

  32. Tonopen • Portable, hand-held, lightweight • Applanation technique

  33. Optic Disk Evaluation • Cupping + pallor (color-pale) • Center depression is the cup • The fibers around the edges are the rim

  34. Glaucoma cupping - asymmetric

  35. Heidelberg Retina Tomograph • 3-D topographic map of ONH

  36. GDx VCC • Looks at the nerve fiber layer • Printout give color-coded picture showing thickness of NFL

  37. Optical Coherence Tomographer OCT • Cross section of retina • Can show macular thickness, retinal NFL thickness and view optic nerve • Compare values over time

  38. Visual Field • Usually VF defects correspond to appearance of damage to optic disk

  39. Visual Field Defects • Enlarged blind spot • Nerve fiber bundle defect • Bjerrum’s scotoma • Nasal depression or nasal step • Last place is central vision

  40. Types of Perimetry • Kinetic • Move object from nonseeing area to a seeing area • Goldmann • Static • Uses stationary test objects presented randomly • Threshold static perimetry • Change intensity of light • Humphrey

  41. Treatment • No cure but can be controlled in many cases • Compliance • Reduction of IOP is principal goal

  42. Treatment • Eye drops • Many types & newer formulations • Side effects

  43. Eyedrops • Miotics • Pilocarpine • Can interfere with vision • Sympathomimetics • Propine • Beta blockers • Timoptic (timolol) • Still used a lot

  44. Eyedrops • Carbonic anhydrase inhibitors • Oral – closed angle • Drops now available • Prostaglandins • Lumigan, xalatan • Alpha agonists • alphagan

  45. Eyedrops • Hyperosmotic • Angle closure & surgery • Many side effects

  46. Compliance • 20-40% of patients miss dosages • Don’t feel “sick” so don’t take meds • Cost • Pick meds with fewer doses per day

  47. Other treatments • Argon laser trabeculoplasty (ALT) • Laser holes into trabecular meshwork • Selective laser trabeculoplasty (SLT) • Less thermal than ALT so less scarring • Excimer laser trabeculostomy (ELT) • Least damage • Waiting FDA approval

  48. Surgery • Create an opening between anterior chamber and subconjunctival space • With or without implant (tube shunt) • Post-op care is critical • Hypotony, wound leak, fluid shifts, infection

More Related