ophthalmology II Flashcards
What is near-sightedness due to
Near-sightedness occurs when the optical power of the eye is too large and causes light to focus in front of the retina
what is far sightedness due to
Far-sightedness occurs when the optical power of the eye is too small and causes light to focus behind the retina
what is astigmatism
Astigmatism describes the shape of the cornea and causes light to focus in front or behind the retina.
presbyopia
another form of refractive error however it results when the eye progressively losses its ability to focus on near objects. It is a symptom caused by natural aging as the lens becomes less flexible. Usually first occurs around 40-50 yrs. The ability to focus on near objects continues to decline throughout our lives
how is visual acuity tested
Standard Snellen Eye chart. Stand 20 ft away and measure one eye at a time, with glasses (or pinhole)
How are visual fields measured
Have patient look at your nose and cover one eye. Hold fingers in periphery at ask how many fingers present. Then repeat for other eye.
how is ocular motility measured
follow finger left, right, up and down
how are pupils tested
Are they round, reactive to light, equal,
how is external eye exam performed
use pen light to observe eyelids, conjunctiva, cornea and anterior chamber
What is the fundoscopic exam
using hand held ophthalmoscope, check red reflex, optic nerve and retina
causes of unilateral red eye
Viral or Bacterial Conjunctivitis, Iritis, Corneal Abrasion, Corneal Ulcer, Herpes Simplex, Herpes Zoster Ophthalmicus, Subconjunctival Hemorrhage
causes of bilateral red eye
dry eyes or allergic conjunctivitis
most common viral cause of conjunctivitis
adenovirus- or after respiratory tract infection
most common cause of bacterial conjunctivitis
staph aureus and strep peumoniae.
compare presentation of bacterial vs viral conjunctivitis
bacterial has more inflammation of conjunctiva. Viral appears more red. Bacterial will have thick, purulent discharge and eyelid can appear more swollen and almost closed