COT Exam- Questions And All Correct
Solutions| 2026 Update
Which type of testing determines the retinas ability to detect subtle
differences in brightness or shading between targets and their
backgrounds? - Ans--Contrast Sensitivity testing
Which machine uses laser lights in a pattern of stripes in which the patient
indicates the orientation of the stripes? - Ans--Laser interferometer
What is the benefit of using a blue stimulus on a yellow background in
automated perimetry? - Ans--Earlier detection of visual field loss
Which type of defects either extend from the blind spot or point toward it? -
Ans--Paracentral
What does the formula P=C/D represent? - Ans--This formula explains the
relationship between the power of a prism and the ability to bend light. P is
prism diopters. C is the displacement of the object in cm, and D is the
distance between the prism and the virtual image in meters.
What is Prince's rule used to measure? - Ans--Near point of
accommodation, and bifocal and trifocal add power.
What is Prentice's rule? - Ans--It's a formula to calculate induced prismatic
effect caused by spectacle lenses whose optical centers have been
decentered so they are not in line with a patients visual axis (pupil center)
The formula is: Induced prism (in prism diopters) = lens power (in diopters) x
optical center displacement (in cm)
Find the total amount of prism induced in the follow situation: Glasses RX
OD +12 sph; OS +10sph; Both optical centers are displaced 5 mm
temporally (centered out). - Ans--OD has 6 prism diopters of BO. OS has 5
prism diopters of BO. The total is 11 prism diopters of BO.
, What is the focal length (in meters) of a 3 diopter lens? -
Ans--P=1/f(meters), 3=1/f, 3f=1f=1/3, or 33cm
What does Snell's law determine? - Ans--Whether the refracted ray will be
bent toward the normal or away from it.
List ways to clean the dust on the lenses of a manual lensmeter - Ans--1.
Blowing the dust off with a clean, rubber bulb syringe
2. A dust brush
3. Compressed canned air
Name 4 examples of lenses that contact the eye and may require
disinfection or sterilization - Ans--1. Diagnostic contact lenses.
2. Fundus contact lens
3. Gonio lens
4. Koeppe lens
Name 10 general types of mechanism of disease and injury - Ans--1.
Infectious
2. Inflammatory
3. Allergic
4. Ischemic
5. Metabolic
6. Congenital
7. Developmental
8. Degenerative
9. Neoplastic
10. Traumatic
Name at least 5 different sources of ocular trauma - Ans--1.
Contusions/abrasions
2. Blow (blunt force)
3. Foreign body
4. Thermal Injury
5. Chemical Injury
6. Toxins
Solutions| 2026 Update
Which type of testing determines the retinas ability to detect subtle
differences in brightness or shading between targets and their
backgrounds? - Ans--Contrast Sensitivity testing
Which machine uses laser lights in a pattern of stripes in which the patient
indicates the orientation of the stripes? - Ans--Laser interferometer
What is the benefit of using a blue stimulus on a yellow background in
automated perimetry? - Ans--Earlier detection of visual field loss
Which type of defects either extend from the blind spot or point toward it? -
Ans--Paracentral
What does the formula P=C/D represent? - Ans--This formula explains the
relationship between the power of a prism and the ability to bend light. P is
prism diopters. C is the displacement of the object in cm, and D is the
distance between the prism and the virtual image in meters.
What is Prince's rule used to measure? - Ans--Near point of
accommodation, and bifocal and trifocal add power.
What is Prentice's rule? - Ans--It's a formula to calculate induced prismatic
effect caused by spectacle lenses whose optical centers have been
decentered so they are not in line with a patients visual axis (pupil center)
The formula is: Induced prism (in prism diopters) = lens power (in diopters) x
optical center displacement (in cm)
Find the total amount of prism induced in the follow situation: Glasses RX
OD +12 sph; OS +10sph; Both optical centers are displaced 5 mm
temporally (centered out). - Ans--OD has 6 prism diopters of BO. OS has 5
prism diopters of BO. The total is 11 prism diopters of BO.
, What is the focal length (in meters) of a 3 diopter lens? -
Ans--P=1/f(meters), 3=1/f, 3f=1f=1/3, or 33cm
What does Snell's law determine? - Ans--Whether the refracted ray will be
bent toward the normal or away from it.
List ways to clean the dust on the lenses of a manual lensmeter - Ans--1.
Blowing the dust off with a clean, rubber bulb syringe
2. A dust brush
3. Compressed canned air
Name 4 examples of lenses that contact the eye and may require
disinfection or sterilization - Ans--1. Diagnostic contact lenses.
2. Fundus contact lens
3. Gonio lens
4. Koeppe lens
Name 10 general types of mechanism of disease and injury - Ans--1.
Infectious
2. Inflammatory
3. Allergic
4. Ischemic
5. Metabolic
6. Congenital
7. Developmental
8. Degenerative
9. Neoplastic
10. Traumatic
Name at least 5 different sources of ocular trauma - Ans--1.
Contusions/abrasions
2. Blow (blunt force)
3. Foreign body
4. Thermal Injury
5. Chemical Injury
6. Toxins
