NCM 116

• Normal intraocular pressure


  10-21 mm Hg
• Intraocular pressure in hypotony

  As low as 0 mm Hg
• Intraocular pressure in some glaucomas

  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 Opthalmoscopy
  • Indirect Opthalmoscopy
  • 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, can decrease 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 Low Vision

  Use of low-vision aids
• Nursing Management for Low Vision

  1. Assist the patient in coping concerning his condition

  2. Ensure patient safety, specially when moving

  3. Assist the patient in mastering spatial orientation
• Glaucoma


  Group of ocular conditions characterized by optic nerve damage

  
• Characteristic features of glaucomatous optic nerve

  • 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
  • Direct mechanical theory (damage in retinal layer as high IOP passes through the optic head)
  • Indirect ischemic theory (high IOP causes compression of ocular microcirculation)
  • Cell injury/Death/Necrosis

  
• 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

  
• Open-angle glaucoma


  Chronic, progressive, and irreversible multifactorial optic neuropathy that is characterized by an open angle of the anterior chamber, optic nerve head changes, progressive loss of peripheral vision, followed by central visual field loss

  
• Closed-Angle Glaucoma


  Glaucoma associated with a physically obstructed anterior chamber angle, which may be chronic or, rarely, acute. Symptoms of acute angle closure are severe ocular pain and redness, decreased vision, colored halos around lights, headache, nausea, and vomiting

  
• Diagnostics for Glaucoma


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

  
• Lifelong Medical Management to Control IOP in Glaucoma

  1. Beta-blockers (one eye is treated first with the other to serve as control/baseline)

  2. Miotic (pupillary constriction, increase in outflow) and adrenergic antagonist, a2-agonist and carbonic anhydrase inhibitors (decrease aqueous humor production)

  3. Prostaglandin (increase in outflow)

  4. Mydriatics (make the pupil of the eye dilate, relax the focusing muscles of the eye, blurred vision is a common side effect)

  
• Surgical Treatment for Glaucoma


  1. Laser Trabeculoplasty (the inner surface of the trabecular meshwork is burned using a laser to enlarge the intertrabecular spaces and to widen the canal of Schlemm to increase outflow of aqueous humor)

  2. Laser iridotomy (an opening is placed in the iris to promote aqueous humor outflow)

  3. Filtering procedure (an opening or a graft is connected to the drainage outside of the eye and reducing the IOP)

  4. Trabeculectomy (removal of the part of the trabecular meshwork, allowing to heal the partially, which would then serve as drainage)

  5. Drainage implant or shunt (similar concept as filtering procedure, but drainage is at episceral plate in the conjunctiva)
• Nursing Management for Glaucoma

  1. Performing health education about the patient's condition and the regimen

  2. Ensure patient safety

  3. Advise relatives to undergo examinations of Glaucoma every 2 years for early detection
• Cataract


  Lens opacity or cloudiness

  
• Pathophysiology of Cataract


  • Multifactorial (environment, co-morbidities, vices)
  • Lens opacity/cloudiness
• Signs and Symptoms of Cataract

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

  
• Medical Management of Cataract

  Surgical Management: Phacoemulsification, Lens Replacement
• Diagnostics for Cataract


  • Snellen chart
  • Slit lamp microscopy
  • Ophthalmoscopy
• Cataract Surgery


  1. Phacoemulsification (the nucleus and the cortex of the lens are liquefied and suctioned for removal)

  2. Lens replacement