Question 1

Contact lenses rest on the moist surface of the

Accepted Answer

cornea.
Contact lenses rest on the moist surface of the cornea. This natural tear layer is sufficient to create surface tension that allows the contact lens to strongly adhere.

Question 2

A poorly fitted contact lens will most commonly result in

Accepted Answer

a corneal abrasion.
A poorly fitted contact lens will most commonly result in a corneal abrasion. If a contact lens has not been fitted properly, it poses the risk of touching the actual cornea instead of resting on the moist layer on the cornea's surface. A corneal abrasion will lead to red eye as well as giving pathogens entry into the cornea.

Question 3

In order to properly fit a patient for contact lenses, the radius of the cornea's curvature must be measured with what instrument?

Accepted Answer

Keratometer
In order to properly fit a patient for contact lenses, the radius of the cornea's curvature must be measured with a keratometer. Also known as an ophthalmometer, this instrument reports the cornea's curvature in diopters.

Question 4

Which of the following conditions preclude a patient from being able to wear contact lenses?

Accepted Answer

Acute seventh nerve palsy (Bell's palsy)
Patients affected by acute seventh nerve palsy (Bell's palsy) are precluded from wearing contact lenses. The reason for this is that the eye does not produce enough moisture to hold the contact lens in place and the contact lens can scratch the patient's cornea.

Question 5

There are generally three variables printed on a contact lens box. What does the marking "(P)" stand for?

Accepted Answer

Power
The marking "(P)" on a contact lens box stands for power. It is typically accompanied by "(BC)" and "(DIA)," which stand for base curvature and diameter, respectively. The power of a contact lens is not always the same as the patient's spectacle correction.With powers greater than 4 diopters, this differencebetween spectacle and contact lenspowers becomes significant enough to consider. Once the analogous contact lens is determined, a trial lens can be worn by the patient and the power refined even further with an over-refraction.

Question 6

Bifocal contact lenses should be considered for patients

Accepted Answer

over the age of 40 who have problems focusing up close.
Bifocal contact lenses should be considered for patients over the age of 40 who have problems focusing up close. Bifocal contact lenses have concentric zones for alternating between near and far vision.

Question 7

What is the imperative first step in inserting contact lenses?

Accepted Answer

Hand washing for at least 15 seconds
The imperative first step in inserting contact lenses is hand washing for at least 15 seconds. This is critical because it prevents bacteria and other pathogens from causing an eye infection. Discuss the importance of cleanliness when putting in and taking out contact lenses, as well as during storage.

Question 8

In what cases are ridged gas permeable contact lenses preferred over soft lenses?

Accepted Answer

All of the above
Although not commonly prescribed, in certain cases ridged gas permeable contact lenses are preferred over soft lenses. In severe cases of dry eyes, astigmatism, and irregularly shaped corneas, ridged gas permeable lenses are used because they are able to replace the natural shape of the cornea with a new refracting surface. Because it will take the patient some time to get adjusted to this type of contact lens, it is important to discuss with the patient how the experience is different form wearing soft lenses.

Quiz 2: Contact Lenses