Blurred vision

Blurred vision

1. Anatomy

   • Layers
     • Fibrous
       • Sclera
       • Cornea
     • Vascular
       • Choroid
       • Ciliary body
       • Iris
     • Nervous
       • Retina

2. Histology

3. Physiology of vision

   • Light hits the retina
     • Rods are turned off
       • Turn bipolar cells on
         • Turn ganglionic cells on
         • On center
           • Off center
             • AMPA
           • mGluR6
   • Phototransduction cascade
     • Light hits rhodopsin on rods
       • Changes cis to trans retinal
         • Transducin breaks up from rhodopsin
           • PDE is activated to decrease cGMP
             • closure of Na channels -> hyper polarization

4. Glaucoma

   • Increased IOP
     • Causes
       • Excessive aqueous production
         • Inadequate aqueous drainage
           • Certain medications (STEROIDS)
             • Eye trauma
       • Symptoms
         • Blurred vision
           • Headache
             • Vision problems
           • Causes
             • Cataract
               • Refractive errors
                 • Myopia (short sightedness)
                 • Hypermetropia (long sightedness)
   • Types
     • Open angle
       • Drainage system blocked
         • Gradual increased IOP >21 mmHg
           • Optic nerve damage
       • Initial loss of peripheral vision then central vision will be affected
     • Closed angle
       • Lens pushing against iris
         • Rapid increased IOP
       • Abrupt onset of redness, eye pain, blurry vision

5. Eye tests

   • Visual acuity
     • Color vision
     • eye's ability to see an in-focus image at a certain distance
   • Refraction assessment
     • Fundoscopy
       • Tonometry
         • puff of air to estimate the pressure in the eye.
           • 11-21 mmHg
       • evaluate the back of your eye, including the retina, the optic disk and the underlying layer of blood vessels that nourish the retina
     • Light waves are bent as they pass through the cornea.

6. Management

   • Treatment goals
     • Preserve vision
       • Decrease IOP
     • Ways to treat
       • Reduced aqueous humor production
         • Increase aqueous humor drainage
           • Prostaglandins
             • Bimatoprost
           • Parasympethatic
             • Pilocarpine
         • Beta blockers
           • Timolol
         • Alpha 2 agonist
           • Apraclonidine
         • CA inhibitors
           • Acetazolamide

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