Optha Disorders

• Normal intraocular pressure


  10-21 mm Hg
• Hypotony


  Intraocular pressure can drop as low as 0 mm Hg
• Glaucoma


  Intraocular pressure can exceed 70 mm Hg
• Ishihara color plates


  • One of the most common and reliable color blind tests
  • Look at images with numbers embedded in dots of color, if you can't see the numbers you're probably colorblind

  
• Main parts of the eye


  • Cornea
  • Iris
  • Lens
  • Macula
  • Optic nerve
  • Pupil
  • Retina
  • Vitreous gel

  
• Aphakia


  Absence of the lens of the eye, due to surgical removal, such as in cataract surgery, a perforating wound or ulcer, or congenital anomaly

  
• Astigmatism


  Common and generally treatable imperfection in the curvature of the eye that causes blurred distance and near vision

  
• Diplopia


  Medical term for double vision
• Hyperemia


  Excess blood builds up inside the vascular system, which is the system of blood vessels in the body
• Hyperopia


  Common vision condition in which you can see distant objects clearly, but objects nearby may be blurry

  
• Myopia


  Common vision condition in which you can see objects near to you clearly, but objects farther away are blurry

  
• Ptosis


  Drooping or falling of the upper eyelid, may be worse after being awake longer when the individual's muscles are tired

  
• Proptosis


  Protrusion of the eyeball

  
• Strabismus


  Condition in which the eyes do not properly align with each other when looking at an object, the eye that is focused on an object can alternate, may be present occasionally or constantly

  
• Assessment


  • Ocular history
  • Visual Acuity
  • External Eye Examination

  
• Diagnostic Evaluation


  • Direct Ophthalmoscopy
  • Indirect Ophthalmoscopy
  • Slit-lamp Examination
  • Color Vision testing
  • Amsler Grid
  • Ultrasonography
  • Optical Coherence Tomography
  • Color Fundus Photography
  • Fluorescein Angiography
  • Indocyanine Green Angiography
  • Tonometry
  • Perimetry Testing
• Refractive Errors


  Vision is impaired because a shortened or elongated eyeball prevents light rays from focusing sharply on the retina, can be corrected with eyeglasses or contact lenses

  
• Myopia


  Nearsighted, have blurred distance vision

  
• Hyperopia


  Farsighted, have excellent distance vision but blurry near vision

  
• Astigmatism


  Irregularity in the curve of the cornea, causes a distortion of the visual image, decreases acuity of distance and near vision
• Low Vision


  Visual impairment that requires patients to use devices and strategies in addition to corrective lenses to perform visual tasks

  
• Blindness


  20/400 to no light perception, legal blindness - best corrected visual acuity does not exceed 20/200

  
• Medical Management for Impaired Vision

  • Use of low-vision aids

  
• Nursing Management for Impaired Vision


  • Assist the patient in coping with their condition
  • Ensure patient safety, especially when moving
  • Assist the patient in mastering spatial orientation
• Glaucoma


  Group of ocular conditions characterized by optic nerve damage, includes generalized or focalized increase in the optic cup size and in the cup-disc ratio

  
• Pathophysiology of Glaucoma


  Closed angle between the iris and cornea OR aqueous humor drainage obstruction, can cause direct mechanical damage or indirect ischemic damage to the optic nerve

  
• Assessment of Glaucoma


  • Blurred vision or halos around light
  • Difficulty in focusing image
  • Difficulty in adjusting to even low lighting
  • Aching or discomfort around eyes
  • Headache

  
• Classifications of Glaucoma


  • Open-angle glaucoma - chronic, progressive, and irreversible optic neuropathy with open angle of the anterior chamber
  • Closed-angle glaucoma - glaucoma associated with a physically obstructed anterior chamber angle, may be chronic or acute

  
• Diagnostics for Glaucoma


  • Tonometry (IOP measurement)
  • Ophthalmoscopy (optic nerve assessment)
  • Gonioscopy (Assessment of anterior chamber angle)
  • Perimetry (Visual field assessment)

  
• Medical Management of Glaucoma


  • Beta-blockers (one eye treated first with the other as control/baseline)
  • Miotics, adrenergic antagonists, a2-agonists, carbonic anhydrase inhibitors (decrease aqueous humor production)
  • Prostaglandins (increase outflow)
  • Mydriatics (dilate pupil and relax focusing muscles)

  
• Surgical Treatment of Glaucoma


  • Laser Trabeculoplasty (burns inner surface of trabecular meshwork to enlarge spaces and widen canal of Schlemm)
  • Laser iridotomy (creates opening in iris to promote aqueous humor outflow)
  • Filtering procedures (create opening or graft to drain aqueous humor outside eye)
  • Trabeculectomy (removal of part of trabecular meshwork)
  • Drainage implant or shunt (drainage at episcleral plate in conjunctiva)
• Nursing Management for Glaucoma


  • Performing health education about the patient's condition and regimen
  • Ensuring patient safety
  • Advising relatives to undergo glaucoma examinations every 2 years for early detection
• Cataract


  Lens opacity or cloudiness

  
• Pathophysiology of Cataracts


  Multifactorial, caused by environment, co-morbidities, and vices, leading to lens opacity/cloudiness
• Signs and Symptoms of Cataracts


  • Painless, blurry vision
  • Reduced contrast sensitivity
  • Sensitivity to glare
  • Myopic shift (returns ability to do close work without glasses)
  • Diplopia
  • Color shift (more on the blue end of spectrum)
  • Brunescence (color values shift to yellow-brown)
  • Reduced light transmission
  • Decreased visual acuity

  
• Diagnostic Tests for Cataracts

  • Snellen chart
  • Slit lamp microscopy
  • Ophthalmoscopy
• Surgical Management of Cataracts


  • Phacoemulsification (nucleus and cortex of lens liquefied and suctioned)
  • Lens replacement
• Nursing Management for Cataract Surgery


  • Withhold anticoagulants 5-7 days pre-operatively
  • Administer dilating drops pre-operatively
  • Provide prophylactic medications pre-operatively
  • Wear protective eye patch 24 hours post-operatively
  • Wear glasses at daytime and eye shield at night for 1-4 weeks post-operatively
  • Clean eye discharge upon waking with a clean, damp washcloth
• Corneal Dystrophies


  Inherited as autosomal dominant traits, characterized by deposits in the corneal layers
• Keratoconus


  Condition characterized by a conical protuberance of the cornea with progressive thinning and irregular astigmatism