Visual Acuity and Eye Examination Methods

Visual Acuity Testing

• Snellen chart used: Patient stands 20 feet from the chart and reads the smallest legible line.
• 20/20 vision: Normal vision; the person sees at 20 feet what most people with normal vision can see at 20 feet.

Refractive Exam

• Purpose: Determine the degree of refractive error (e.g., nearsightedness, farsightedness).
• Dilating drops: Anticholinergics.
• Pupil dilation purpose: Allows a better view of internal eye structures.
• Instrument: Phoropter; Different lenses are presented and the patient indicates which provides the clearest vision. This determines the corrective lens strength.

Ophthalmoscopic Exam

• Use: Examiner uses an ophthalmoscope to view the retina and other internal structures through the pupil.

Slit Lamp Exam

• Function: Specialized microscope with a light beam to view the eye's front structures.
• Structures viewed: Conjunctiva, cornea, anterior chamber, iris, lens, and anterior vitreous.

Tonometry

• Measurement: Intraocular pressure (IOP).
• Method: A small cone touches the numbed cornea measuring the pressure to flatten a part of the cornea.

Refractive Errors

• Myopia: Light focuses in front of the retina; blurry distant vision.

• Hyperopia: Light focuses behind the retina; blurry close vision.

• Astigmatism: Light focuses on two different points on the retina; distorted vision.

• Presbyopia: Light focuses behind the retina; decreased close vision.

• Correction: Glasses or contact lenses.

• Types of Glasses:

  • Bifocals: Two different lenses in one frame.
  • Trifocals: Three different lenses in one frame.

This quiz covers essential methods of eye examination, including visual acuity testing, refractive exams, and specialized equipment like the ophthalmoscope and slit lamp. Understand the purpose and techniques used in assessing eye health and vision clarity. Perfect for students in optometry or healthcare fields.