Objective 4

Question 1

The only accurate method of determining the power and fit of a rigid lens that is being fitted on a cornea distorted by previous lens wear is by the use of trial lenses method and performing ____________ over the lenses.

Answer 1

refraction

Question 2

____________ is improved by contact lenses in patients who have nystagmus, because the lenses move with the abnormal eye movements associated with this condition.

Answer 2

Visual acuity

Question 3

Vessel growth of greater than _____ millimetres into the corneal stroma is considered a contraindication to further contact lens wear.

Answer 3

two

Question 4

Corneal __________ occurs as a result of prolonged PMMA wear.

Answer 4

desensitization

Question 5

For patients who have poor results from RK surgery fitting with RGP lenses will improve visual acuity and reduce ________.

Answer 5

Glare

Question 6

Abnormal sensitivity to light is called___________.

Answer 6

photophobia

Question 7

_________________ is created by the crystalline lens of the eye or the posterior surface of the cornea.

Answer 7

Residual astigmatism

Question 8

A disturbance of the epithelium characterized by dot-like staining is referred to as _________________.

Answer 8

stippling

Question 9

Decreased corneal sensitivity in long-term PMMA wearers is caused by _______________.

Answer 9

hypoxia

Question 10

The only accurate method of determining the power and fit of a rigid lens being fitted on a cornea distorted by previous lens wear is to perform ___________________.

Answer 10

over refraction

Question 11

Corneal ______ is necessary when a contact lens has caused a measurable amount of damage to the cornea. This may happen because of a poor fit or may be the result of patient ____. Any type of contact lens can cause corneal ____.

Answer 11

rehabilitation
misuse
warpage.

Question 12

Symptom: Halos around lights at night with or without lenses. This symptom is caused by _____. The light does not pass directly through the cornea but is reflected and refracted at unexpected angles.

Answer 12

edema

Question 13

Symptom: Spectacle blur. When eyeglasses are worn after removal of contact lenses, the patient’s vision may not clear immediately. Blurring for over ____ is considered unacceptable. A few minutes of blur is normal.

Answer 13

one half hour

Question 14

Symptom: Decreased visual acuity with glasses and contact lenses. As the cornea becomes increasingly _____, correctable vision decreases or becomes hazy and cloudy.

Answer 14

irregular

Question 15

Symptom: Episodes of acute ____ crisis.

Answer 15

corneal

Question 16

Symptoms: Photophobia, even in low lighting and resulting squint. Light sensitivity is caused by ____. This problem can be minor or a patient may squint so much that _____ occur.

Answer 16

edema

headaches

Question 17

Symptoms: Decreased wearing time often associated with ___.

Answer 17

GPC.

Question 18

Signs: Corneal swelling allowing an accumulation of moisture in the cells. This is viewed through the slit lamp or with the naked eye as ______ .

Answer 18

edema

Question 19

Signs: Pumping action of the _______ is inhibited due to endothelial _____ which can be viewed as endothelial _____. According to Hom this is a transient event with an unadapted eye (______) that _____ result in cell loss. However, according to Efron, prolonged hypoxia will likely cause contact lens-induced endothelial _____ which will cause endothelial cells to ___, leading to _______.

Answer 19

endothelium
edema 
blebs
new contact lens wearer
does not
acidosis
die
polymegathism

Question 20

Signs: Altered K readings – K’s may steepen. For the purpose of this course, a change in a K-reading of 0.75 diopters or more is considered ______ and may be associated with excessive _____.

Answer 20

abnormal

edema

Question 21

Signs: Rx changes. This is sometimes referred to as “________” in patients who wear extended-wear lenses or consistently over-wear lenses of any kind.

Answer 21

creeping myopia

Question 22

Signs: Corneal ______ occurs. A patient with _____ will not be alerted to the problems which lead to corneal damage.

Answer 22

desensitization

desensitization

Question 23

Signs: New blood vessels grow into the cornea. The cornea is normally ____, and __________ never resolves itself. The blood in the vessels will recede, leaving “____” vessels, but these vessel sheaths refill with blood when the eye is subjected to any adverse conditions. Older vessels, which are no longer growing in will sometimes ____ back out. Vessel growth of greater than _____ into the corneal stroma is considered a ________ to further contact lens wear.

Answer 23

avascular
neovascularization
ghost
loop 
two millimetres
contraindication

Question 24

Signs: Irregular astigmatism may occur. The _____ of the cornea does not necessarily alter in regular proportions. The resulting irregular astigmatism is a classic sign of ______.

Answer 24

shape

over-wear.

Question 25

All of these signs are generally reversible with the exceptions of ______ and ______.

Answer 25

vascularization

polymegathism

Question 26

_________ lenses reduce the problems caused by prolonged wear of PMMA lenses. They allow more oxygen to reach the cornea and prevent the _______ of the epithelium and Bowman’s membrane.

Answer 26

Gas permeable

degradation

Question 27

The “____________” allows the cornea to stabilize for 48 hours before keratometer measurements are taken. It is unrealistic because corneal and refractive changes move in the direction of ____ K-readings in the primary meridian and less minus refractive error for a period of 3 to 4 days before they reverse or stabilize. Therefore, any K-readings taken 48 hours or ____ after lens removal, will give values that are erroneous.

Answer 27

48-hour rule of thumb
flatter
later

Question 28

An _______ is a reaction of the cornea to the hypoxia that results when normal wearing time is exceeded with _____ lenses. The condition begins in the early hours of the morning. The patient awakens in __________ and vision is greatly impaired. Typical clinical findings include central epithelial erosions, pronounced ciliary ____, swelling of the lids, and a ______ pupil. Referral to an ophthalmologist is ______.

Answer 28

acute corneal crisis
PMMA
excruciating pain
injection
constricted
urgent

Question 29

The usual treatment for acute corneal crisis is instillation of a local ____ and administration of a tight patch to the affected eye. Often analgesics for pain and a _____ agent to relieve the ciliary spasm are prescribed. The patient is advised to stay in a ____ room as the constriction and dilation of the pupil in the unaffected eye will cause the pain to increase. A hypnotic may be prescribed to facilitate sleep. The patient should discontinue wearing of contact lenses for _____ days.

Answer 29

anesthetic
cycloplegic
dark
4 to 5

Question 30

If there is a significant degree of corneal insult, i.e. corneal staining, one may elect to discontinue PMMA lens wear for a period of time (generally ____ or longer) until the cornea rehabilitates. It is important to remember that wearers of PMMA lenses often show corneal flattening during the first two or three days after lens removal. This is followed by gradual ____, usually over a period of three weeks back to pre-fitting levels.

Answer 30

3 weeks

steepening

Question 31

The majority of the induced corneal changes are reflected by the increased amount of irregular astigmatism, which is better managed by refitting the patient immediately with __________ lenses.

Answer 31

rigid gas permeable

Question 32

When refitting a patient immediately with rigid gas permeable lenses, it is important to use _______ to evaluate overall lens performance. _____ due to induced irregular astigmatism are generally not reliable.

Answer 32

diagnostic lenses

K readings

Question 33

Patients should be informed that corneal rehabilitation is a slow, gradual process which may take _____________.

Answer 33

weeks to months

Question 34

Since wearing rigid gas permeable lenses will ______ this condition, the patient who has not been aware of corneal sensations with PMMA lenses will begin to notice the RGP lenses. These patients must be informed that this is likely to occur and must be _____ carefully for optimal physical comfort.

Answer 34

reverse

refitted

Question 35

A PMMA lens wearer who would like to switch to rigid gas permeable lenses should be refit ______. The cornea goes through many changes in curvature in the first _________ after PMMA lens removal. A refraction or K-reading taken at this time will likely be _____ if the patient has worn PMMA lenses for any appreciable length of time.

Answer 35

immediately
three to four days
invalid

Question 36

The time required for stabilization of the cornea of a PMMA lens wearer after lens removal is from one day to many months.

Answer 36

stabilization

Question 37

The trial lens method with ______ is the only accurate method of determining the power and fit of a rigid lens being fitted on a cornea distorted by previous lens wear.

Answer 37

over-refraction

Question 38

When refitting a patient, it is important to know that there are certain skin diseases which prohibit the wearing of contacts. If a patient has seborrhea, psoriasis, neurodermatitis, chronic blepharitis or inflamed lid margins, the condition should be noted on the chart.

Answer 38

It may be possible for people with these conditions to wear contacts; however, the potential for problems is likely.