Theory of Refraction Flashcards
Pseudomyopia which is caused by an involuntary contraction of the ciliary muscle may be relieved by doing what?
Giving the patient plus correction to relax accommodative effort
Which of the following would be a subjective procedure? Visual Acuity Test, Retinoscopy, Autorefraction, Slit lamp evaluation
Visual Acuity Test
If parallel rays of light come to a point of focus in front of the retina in the eye, what condition may the patient have?
Myopia
A slit lamp is also referred to as which of the following? Bioscope, Biomicroscope, Slit Beam, all of the above
Biomicroscope
If parallel rays of light come to a point of focus behind the retina in the eye, what condition may the patient have?
Hyperopia
In history taking, it is important to identify the chief complaint of the patient for what reason?
To determine the main reason for seeking the exam
What does the acronym SOAP stand for?
Subjective, Objective, Assessment, Plan
A slit lamp can be used for all of the following except? Evaluating tear film, evaluating ocular disease, assessing corneal health, checking cranial nerves
Checking cranial nerves
If parallel rays of light come to two points of focus in front of the retina of the eye, what condition may the patient have?
Myopic astigmatism
Which of the following is not a false statement? A refraction is not a comprehensive eye evaluation, a refraction is a comprehensive eye evaluation, a refraction includes visual acuity of the patient, A refraction generally will not identify ocular health concerns
A refraction is not a comprehensive eye evaluation
Given keratometry readings of 43.00D@180/42.00D@090 and a manifest Rx of -2.00 -1.00 x 180, what type of astigmatism would the patient have?
Corneal astigmatism
Of the following statements, which one is true? Autorefractions can be used in the place of a refraction, autorefractions should be used in the place of a refraction, autorefractions should not be used in the place of a refraction, autorefractions should never be a starting point of a refractions
autorefractions should not be used in the place of a refraction
Which type of tonometry achieves the measurement by the force required to flatten a constant area of the cornea?
Applanation tonometry
What type of tonometry is the Goldman tonometry?
Applanation tonometry
A phoropter can be used for all of the following except what? Objective sphero-cylindrical refraction, subjective sphero-cylindrical refraction, to determine possible muscle imbalances in a patient, corneal health
Corneal health
What are keratometers used for?
Measuring approximately 3mm of the central corneal cap
Corneal topography can be used for which of the following? Measuring the corneal powers in different meridians of the eye, measuring approx. 3mm of the central corneal cap, assessing overall corneal health, all of the above
Measuring the corneal powers in different meridians of the eye
Average pressures within the human eye should be within a range of what?
16-20 mmHg
Visual Field Analyzers are used for which of the following except: Vertical range of vision, horizontal range of vision, IOP, Scotomas
IOP
Given Keratometry readings of 43.00D@180/42.00@090 and a manifest Rx of -2.00 -1.00 x 180, what type of astigmatism would the patient have?
Corneal astigmatism
Keratometry readings of 42.00D@180/43.00@090 indicate what?
With the Rule Astigmatism
Keratometry readings of 43.00D@180/42.00@090 indicate what?
Against the Rule Astigmatism
What is a tangent screen used for?
A very basic visual field testing process
If a person has difficulty in seeing light shades of gray on a white background, they may have a problem with what?
Contrast sensitivity
The brain is relatively insensitive to what neurologists call what?
Low spatial frequencies
What is a fundus camera used for?
To photograph the interior surface of the eye, including retina, optic disc, macula, and posterior pole
What is a tonometry used for?
To measure the intraocular pressure of the eye
What is the best way to describe 20/20 vision?
It is identified as a quantitative measure of the ability of the eye to identify the smallest elements of a letter or object to correctly identify the letter or object
If a patient correctly identifies all but two letters on the 2/25 line how would it be recorded?
20/25-2
When performing a refraction, if the refractionist can get the patient to 20/50 but is having difficulty improving vision, what is the next step?
Use a pinhole occluder test
If all light rays come to a point focus on the retina, what is the condition?
Emmetropia
What is a general term for any error of refraction in the eye?
Ametropia
If a patient is unable to read any letters on the Snellen chart at the standard distance, they may have reduced visual acuity. What may be done to test them?
Reduce the testing distance
For a patient with reduced visual acuity, if they see a light as it moves up and down, the testing in recorded how?
LP
When testing a patient and he/she demonstrates no vision, the testing is recorded how?
NLP
What is the push up method/test?
It is used to determine the near point of accommodation by moving a test object closer to the eye until it blurs
The correction for a condition whereby light rays come to a single point focus in front of the retina would be illustrated by which Rx?
-3.00
When using the duochrome test, if the patient indicates the green side is clearer, what is the condition?
The patient is over plussed
A patient’s visual acuity is recorded as 20/200 SC. This would indicate:
Their acuity without correction
___ means that eyes that are “carried correctly” and proper extraocular muscle tonicity is maintained.
Orthophoria
