Physician Assistant Exam: Conditions that Affect the Lens of the Eye
The Physician Assistant Exam will expect you to know about conditions of the eye, including the lens. The lens of the eye can be affected by several conditions, including cataracts, corneal trauma, and foreign bodies. The latter two conditions you likely saw during your time in the ER.
Cataracts — partly cloudy
Cataracts, or cloudy areas, are a very common condition that affects the lens. Over time, the affected person loses the ability to see. Many systemic conditions can cause cataracts, common ones being hyperparathyroidism and diabetes. Steroids can cause them as well. Astronauts who have left Earth orbit have a high incidence of cataracts, possibly due to cosmic rays. One big cause is just getting older. The treatment is usually surgical.
The cornea is the outermost part of the eye, and it’s susceptible to trauma. By trauma, this refers to anything that scratches the eye. Signs can include increased lacrimation, a sensation of fullness in the eye, eye itching, and pain.
A regular ophthalmoscope may miss a small corneal abrasion. You need a slit lamp and fluorescein dye to get a really detailed look at the eye. The treatment of a corneal abrasion is usually conservative, although sometimes topical antibiotics may be prescribed.
A corneal ulcer is a bacterial infection of the cornea. There are a variety of causes, including Staph, Strep, and Pseudomonas. The diagnosis is confirmed with fluorescein angiography. The treatment is topical antibiotics and/or antifungals. One viral infection that you can’t forget is herpetic keratitis. Herpes simplex keratitis commonly presents with a dendritic ulcer.
The eye can be subject to trauma from objects flying into it. For many activities — carpentry, machining, welding, or target shooting, for example — wearing eye protection is vital. The treatment for eye trauma depends on how much of the eye is affected.
Foreign objects can cause significant injury. The ophthalmologist needs to see the person pronto to do a slit-lamp examination to determine the extent of the damage. This is a full examination to make sure that the person has no bleeding in the eye or problems with the pupil.