Blurred vision

Anatomy
1. Layers
  1. Fibrous
    1. Sclera
    2. Cornea
  2. Vascular
    1. Choroid
    2. Ciliary body
    3. Iris
  3. Nervous
    1. Retina
Histology
Physiology of vision
1. Light hits the retina
  1. Rods are turned off
    1. Turn bipolar cells on
      1. Turn ganglionic cells on
      2. On center
        Off center
        AMPA
        mGluR6
2. Phototransduction cascade
  1. Light hits rhodopsin on rods
    1. Changes cis to trans retinal
      1. Transducin breaks up from rhodopsin
        PDE is activated to decrease cGMP
        closure of Na channels -> hyper polarization
Glaucoma
1. Increased IOP
  1. Causes
    1. Excessive aqueous production
      1. Inadequate aqueous drainage
        Certain medications (STEROIDS)
        Eye trauma
    2. Symptoms
      1. Blurred vision
        Headache
        Vision problems
        Causes
        Cataract
        Refractive errors
        Myopia (short sightedness)
        Hypermetropia (long sightedness)
2. Types
  1. Open angle
    1. Drainage system blocked
      1. Gradual increased IOP >21 mmHg
        Optic nerve damage
    2. Initial loss of peripheral vision then central vision will be affected
  2. Closed angle
    1. Lens pushing against iris
      1. Rapid increased IOP
    2. Abrupt onset of redness, eye pain, blurry vision
Eye tests
1. Visual acuity
  1. Color vision
  2. eye's ability to see an in-focus image at a certain distance
2. Refraction assessment
  1. Fundoscopy
    1. Tonometry
      1. puff of air to estimate the pressure in the eye.
        11-21 mmHg
    2. evaluate the back of your eye, including the retina, the optic disk and the underlying layer of blood vessels that nourish the retina
  2. Light waves are bent as they pass through the cornea.
Management
1. Treatment goals
  1. Preserve vision
    1. Decrease IOP
  2. Ways to treat
    1. Reduced aqueous humor production
      1. Increase aqueous humor drainage
        Prostaglandins
        Bimatoprost
        Parasympethatic
        Pilocarpine
      2. Beta blockers
        Timolol
      3. Alpha 2 agonist
        Apraclonidine
      4. CA inhibitors
        Acetazolamide

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Blurred vision

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	Created by Fatima Alkhateeb about 6 years ago