O
Oligodendrocyte - (See: Glia Cells - Oligodendrocyte)
Optic Atrophy - Degeneration of the Optic Nerve, due to DeMyelination and loss of Blood Vessels on the Optic Nerve Head, seen as pallor through the Ophthalmoscope. #01, #25
Optic
Nerve - The Second Cranial Nerve is the bundle of Nerve Fibers formed by the light sensitive Retina of the Eye that extends from the Eye and connects to the Brain. #25
Optic Neuritis - Is inflammation of the Optic Nerve (behind the Eye, aka RetroBulbar Neuritis). Acute Optic Neuritis causes (Rapidly Progressive Acuity Loss, Decreased Color Perception and Contrast Sensitivity (Dyschromatopsia), Central Visual Field Loss (Central Scotoma), Blurred Vision, Afferent Pupillary Defect, and Transient or Permanent Loss of Vision).
- Optic Neuritis (ON) most often includes Pain with Eye movement, in or behind the Eye when Vision deteriorates. ON episodes often reappear, each reaching a peak within days, and recovery takes from 5 weeks to six months - with or without any particular treatment.
See: CorticoSteroids In Optic Neuritis
- An ON attack is often an invisible (subclinical) event, symptoms are either not noticed, or simply dismissed. Fortunately, subsequent Visual Evoked Potential (VEP) testing always registers this prior damage, as slowed response times. This finding can be used to fullfill MS's diagnostic requirement of a previous attack (Time Dissemination), or involvement of a second (Space Criterion) CNS Functional System.
- Optic Neuritis is very common in many, but not all MSers and usually occurs in only one Eye at a time. It is one of the first diagnosable signs that you may have Multiple Sclerosis. Although acute Optic Neuritis is very upsetting and scary, ON is considered a good indication, of having a milder MS course, when it is the presenting symptom. #25
- When the inflammation involves the first part of the Nerve and can be seen at the Optic Disk, usually during the course of an Eye Examination, it is called Optic Papillitis. This may cause colors to appear washed-out or faded and bright lights generally make seeing difficult, even when there are good color contrasts.
- Wearing yellow tinted sunglasses or adding a light photo-ray tint to your eyeglass prescription, greatly reduces the glare of bright lights and the feeling of Dizziness.
(Also See: Diplopia, Afferent Pupillary Defect, Retrobulbar Neuritis, Nystagmus, Oscillopsia, Dyschromatopsia, InterNuclear Ophthalmoplegia, & Diagnosing MS)
Organelle (Little Organ) - Particles within Cells that are covered with their own membrane. Many different kinds of Organelles occur within Cells, each with a special function. #01
Oscillopsia - Continuous, Involuntary, and Chaotic Eye movements that result in a Visual Disturbance, in which objects appear to be Jumping or Bouncing. #28 (Also See: Nystagmus)
Orthotic
- A mechanical appliance such as a Leg brace
or Shoe inserts that are specially designed to Control, Correct, or Compensate for impaired limb function. #28
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since August 10, 1999.
