There are many causes of eye pain and visual loss. I would like for you to be familiar with the most common causes, know what treatment to use in the field, and know when it’s an emergency.
First, some practical anatomy. The eye converts light into chemical and electrical activity that the brain interprets. Approaching the eye from the outside, you first encounter the cornea which covers the pupil. The iris surrounds the pupil and gives your eyes their color. The iris is a group of muscles that control the pupil’s size.
Proceeding inward, the lens is encountered next followed by the vitreous which is the jelly-like substance that fills the eye. Small muscles (ciliary) control the shape of the lens. Often times, with age, the lens becomes less flexible and the little muscles become less effective. This and refractive errors are why corrective lens are required.
The retina and macula form a layer at the back of the eye and turn light energy into chemical and electrical impulses which travel through the optical nerve to the back of the brain (occipital lobe) primarily.
The white of the eye is the sclera and it is covered by a clear membrane called the conjunctiva. The conjunctiva turns red when irritated. The sclera, conjunctiva, and the cornea will be our primary focus in emergencies, but it is essential to recognize other emergent symptoms.
The history is of utmost importance. Symptoms to ask about:
- Is it possible that a foreign object got into the eye
- How long have the symptoms been present
- Pain, or light bothering the eye(s). If there is pain, is it superficial, deep, or throbbing
- Visual loss or decreased vision
- Certain areas of visual loss
- Is the eye inflamed (red)
- One eye or both
- Neck stiffness
- Fever/ chills
- Flashing lights or halos
- Any similar problems in the past
Examination in the field. Perform as much as possible. Check:
- Temperature, heart rate, and blood pressure
- Redness or blood in the whites (conjunctiva) of the eye
- Full range of eye movement and is it equal in both eyes
- Visual fields. Cover one of the person’s eyes and have them look straight ahead, with your index finger 2 feet away move it in upper, outer, downward, and medial quadrants to assess any areas of blindness. Repeat for the other eye. This will also help assess visual acuity.
- Is the eye bulging (proptosis)
- Is there tenderness of either temporal region when you press on them
- Do the pupils dilate and constrict equally
- If light bothers one eye, have them cover it and shine a light in the opposite uncovered, unaffected eye. If this causes discomfort in the symptomatic eye, it is called photophobia of the symptomatic eye.
RED FLAGS: If possible seek immediate medical attention. Examples given aren’t all of the possibilities. Sudden or gradual onset of the following:
- Visual changes with fever, chills, nausea, or vomiting (meningitis, encephalitis, botulism)
- Sudden: loss of vision, blurred vision, loss of particular areas of vision e.g. lose vision in the left half of both eyes or the top half of both eyes like a shade pulled down. (All are suggestive of a stroke or complicated migraine among other conditions)
- Seeing halos around light (glaucoma)
- Deep eye pain (a symptom of many ophthalmologic disorders including glaucoma and infections)
- Bulging eye, called proptosis or exophthalmos (thyroid, tumors or infections behind the eye)
- Swollen eye from unknown causes (infection)
- Swelling of half of the face including the eye especially with tooth pain (facial or tooth abscess related infection)
- Painful rash in the area of the eye, forehead, and/or temporal area (herpes ophthalmica) Warning: always wear gloves and do not allow the person to touch their eyes. This is highly contagious on contact and can lead to blindness and worse.
Link to part 2 of 2:Eye Pain – Is It an Emergency ? (Part 2 of 2)
This is meant to be a field guide; not a comprehensive ophthalmological post.
Resources for further study:
National Eye Institute http://www.nei.nih.gov
American Academy of Ophthalmology http://www.aao.org/young…/top-10-eye-emergencie.
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