Certified Paraoptometric (CPO) - Unit III - Clinical Principles and Procedures

Visual Acuity (VA) Correct Answer: The meausure of the finest detail the eye can detect. Typically described as a Snellen fraction. Snellen Letters Correct Answer: Letters most often used to measure acuity at distance. Snellen Fraction (20/20) Correct Answer: = Testing Distance / Distance at which letter is standardized to be read Snellen numerator Correct Answer: Testing distance (usually 20 feet) Snellen denominator Correct Answer: Distance at which the letter is supposed to be read. Cover/Uncover/Alternative-Cover Testing Correct Answer: Examines the binocular relationship of the eyes. The patient is asked to fixate on a distant object (or near) while their eyes are observed. Exotropia Correct Answer: One eye fixating while the other deviates outward. Esotropia Correct Answer: One eye fixating while the other deviates inward. Hypertropia Correct Answer: One eye fixating while the other deviates upward. Keratometry/Ophthalmometry ("K-reading") Correct Answer: Measures the curvature and focusing power of the cornea. Allows you to estimate the focusing power of the cornea, the amount of astigmatism present, and give an evaluation of the integrity of the front surface of the eye. Used in estimating CL base curve. Topography Correct Answer: Basis lies with Placido disk technology. Precisely analyzing the radius of the curvature and the refractive power at thousands of points across the cornea. It assists with evaluating refractive problems in the cornea and is an excellent tool for refractive surgery (pre-op & post-op). Retinoscopy Correct Answer: An objective measure of the refractive power of the eye. Examiner shines the light into the patient's eye and observes the reflex seen in the patient's pupil. The concept is based in movement of the reflex and finding the lens that will stop that movement (neutralizing it).