CLSA CD Questions Flashcards
The cornea is one of the few __________ tissues in the body.
A. Vascular
B. Avascular
C. Multi-layered
D. Collagen
Avascular
Which layer of the tear film is considered to play the most significant role in inhibiting evaporation from the corneal surface?
A. Mucin
B. Aqueous
C. Lipid
D. Electrolytes
Lipid Layer
What is the term used to describe the morphological changes in the cell size of the corneal endothelium?
A. Pleomorphism
C. Guttata
B. Polymegathism
D. Hyperplasia
Polymegathism
When corneal epithelial cells suffer trauma, the first step toward
resolution is:
A. Sliding and migrating of the adjacent remaining epithelial cells
B. The formation of an infiltrate
C. An increase in basal cell formation
D. Acceleration of the endothelial cell function
Slide and migrate adjacent remaining cells.
Contributors to increased tear film evaporation include
all of the following except:
A. Large palpebral fissures
B. Proptosis
C. Ptosis
D. Meibomian gland dysfunction
Large Palpebral fissures Proptosis: Protrusion of the eye Meibomain gland dysfunction But not
B. Ptosis: because it lower the lids which decreases how much of the eye is hitting the air.
Conjunctival goblet cells produce lipids necessary to convert the ocular surface into a:
A. Hydrophobic surface
B. Hydrophilic surface
C. Ionic surface
D. Non-ionic surface
Hydrophilic Surface
Giant papillary conjunctivitis is a condition that primarily affects the:
A. Bulbar conjunctiva
B. Tarsal conjunctiva
C. Sclera
D. Lid margin
Tarsal Conjuntiva
Lash loss is most common in which of the following conditions:
A. Blepharitis
C. Ptosis
B. Distichiasis
D. Ectropion
Blepharitis
Normal histology of the corneal epithelium includes all of the following except:
A. Wing cells
B. Basal cells
C. Squamous cells
D. Keratocytes
Keratocytes
Which of the following help to limit corneal edema and maintain corneal deturgescence?
A. Tear evaporation
B. Healthy corneal endothelial layer
C. Tear film tonicity
D. All of the above
D. All of the above
The primary source of oxygen to the anterior cornea in the open eye state is:
A. Atmosphere
B. Aqueous humor
C. Limbal vascularization
D. Palpebral conjunctival vascularization
Atmosphere (air)
A pigmented area that may be found on the sclera or iris is called a:
A. Nevus
B. Necrosis
C. Infiltrate
D. Hemorrhage
Nevus
The integrity of the lipid layer of the precorneal tear film may be most appropriately evaluated by:
A. Tear BUT
B. Schirmer test
C. Rose Bengal test
D. Zone Quick test
Tear But Test
A condition that describes an atypical accessory row of eyelashes is known as:
A. Trichiasis
B. Ectropion
C. Epiblepharon
D. Distichiasis
Distichiasis: is a rare disorder defined as the abnormal growth of lashes from the orifices of the meibomian glands on the posterior lamella of the tarsal plate.
As a result of chronic hypoxia, microcysts can occur in:
A. Corneal epithelium
B. Subepithelial tissues
C. Conjunctiva
D. Corneal stroma
Corneal Epithelium
Corneal infiltrates represent an aggregation of:
A. Lipids
B. White blood cells
C. Calcium
D. Keratocytes
White Blood Cells
Corneal infiltrates may be found in which layer of the cornea?
A. Epithelium
B. Sub-epithelium
C. Stroma
D. All of the above
D. All of the Above
The principle direction of movement of the lower eyelid during the blink phase is:
A. Medial
B. Superior
C. Lateral
D. None
Lateral
Hypertrophy of the bulbar conjunctiva, which extends beyond the limbus to involve the cornea is termed:
A. Pinguecula
B. Lymphangietasia
C. Chemosis
D. Pterygium
Pterygium
Meibomian gland dysfunction will most directly influence which layer of the precorneal tear film?
A. Mucin
B. Aqueous
C. Lipid
D. All layers are affected equally
Lipid
Choose the value that best represents the average thickness of the precorneal tear film.
A. One mm
B. One micron
C. 0.5 mm
10 microns or .01mm
Corneal neovascularization may occur as a result of:
A. Infection
B. Hypoxia
C. Inflammation
D. All of the above
D. All of the above
The most accurate method to identify the corneal apex is with the:
A. Keratometer
B. Tonometer
C. Videokeratoscope
D. Photokeratoscope
Videokeratoscope
A corneal ulcer, by definition, must have associated:
A. Infiltration
B. Infection
C. Tissue loss
D. Injection
Tissue Loss
- Which of the following soft lens materials is most likely to become coated with deposits?
A. Low water content non-ionic
B. High water content non-ionic
C. Low water content ionic
D. High water content ionic
D. High water content ionic
Corneal microcysts are most apparent via biomicroscopy with which method of illumination?
A. Direct
B. Specular
C. Retro
D. Sclerotic scatter
C. Retro
The corneal stroma, as the largest corneal layer, comprises what percentage of corneal thickness?
A. 98
B. 90
C. 75
D. 60
B. 90
During a yearly soft contact lens exam, a patient presents with the following subjective symptoms: itching, during and after lens removal, mucous and mattering upon awakening, and the lens dislodging off center. What should the practitioner be looking for during the slit lamp exam?
A. Giant papillary conjunctivitis
B. Superior epithelial arcuate lesion (SEAL)
C. Diffuse punctate stain
D. Corneal abrasion
A. Giant papillary conjunctivitis
The first line of defense in the protective system of the eye
is formed by the:
A. Sebaceous glands
B. Lacrimal glands
C. Eyelids
D. Caruncle and semilunar folds
C. Eye Lids
Which of the following would most effectively steepen the lens to cornea relationship of a gas permeable lens?
A. Increase overall diameter and decrease optic zone diameter
B. Increase overall diameter and increase optic zone diameter
C. Increase optic zone diameter and decrease overall diameter
D. Increase optic zone diameter and flatten base curve
B. Increase overall diameter and increase optic zone diameter
A yellowish, thickening of bulbar conjunctiva, nasal or temporal to the cornea that does not encroach onto the cornea is called a:
A. Pterygium
B. Pinguecula
C. Chalazion
D. Infiltrate
B. Pinguecula
The most powerful refracting surface of the eye is the:
A. Retina
B. Cornea
C. Crystalline lens
D. Ciliary muscle
B. Cornea 42 D to 43 D
The layer of the cornea that is unable to regenerate if cells are lost through aging, trauma or surgery is the:
A. Endothelium
B. Epithelium
C. Stroma
D. Descemet’s membrane
A. Endothelium
The angle structure of the eye consists of:
A. The iris, cornea, portion of the posterior ciliary body, lens ciliary muscle and Canal of Schlemm
B. Scleral spur, cornea, uveal tract, Descemet’s membrane and vitreous
C. Cornea, iris, trabecular meshwork, Bowman’s membrane and suspensory ligaments
D. Root of the iris, portion of the anterior ciliary body, scleral spur, trabecular meshwork and Canal of Schlemm
D. Root of the iris, portion of the anterior ciliary body, scleral spur, trabecular meshwork and Canal of Schlemm
Glaucoma is characterized by:
A. A clouding of the crystalline lens, elevated intraocular pressure and loss of central vision
B. Elevated intraocular pressure, visual field loss and damage to the optic nerve head
C. Elevated intraocular pressure, an altitudinal visual field defect, and loss of central vision
D. Visual field loss, clouding of the crystalline lens, and poor drainage through the trabecular meshwork
B. Elevated intraocular pressure, visual field loss and damage to the optic nerve head
The vitreous is:
A. A vascular structure between the sclera and the retina
B. A thick, jelly-like structure that fills the posterior 2/3 of the eye
C. A clear, watery fluid that flows from the posterior chamber of the eye, through the pupil to the anterior chamber
B. A thick, jelly-like structure that fills the posterior 2/3 of the eye
What is a condition of the cornea that occurs as a result of a variance in diameter or distance between collagen fibers?
A. Pain
B. Edema
C. Pigment deposition
D. Dryness
B. Edema
The average life span of a corneal epithelial cell from mitosis through maturation and desquamation most nearly approximates:
A. One day
B. One week
C. One month
D. One year
B. One week
Which keratometer reading indicates with-the-rule astigmatism?
A. 45.00 @ 175 / 44.50 @ 85
B. 48.00 @ 45 / 46.50 @ 135
C. 44.50 @ 15 / 44.75 @ 105
D. 46.00 @ 180° / 46.00 @ 90°
C. 44.50 @ 15 / 44.75 @ 105
What RGP lens design is indicated when a spherical lens shows a fluorescein pattern showing a black shaped area of touch in the horizontal meridian and pooling in the vertical meridian?
A. Residual toric lens
B. Aspheric lens
C. Bifocal lens
D. Posterior toric lens
D. Posterior toric lens
Fluorescein patterns can be very helpful in determining the final fitting parameters of an oxygen permeable contact lens. Areas that are bright green reflect areas where there is a great deal of distance between the posterior surface of the lens and the anterior surface of the cornea. When areas are dark, they indicate areas where there is little space between the back of the lens and the front of the eye. When the fluorescein pattern of a spherical RGP lens shows a black shaped area of touch in one meridian opposed to an area of excessive lift, the best way to improve this fit is with an oxygen permeable lens that has two separate curves on the back (posterior) surface of the lens. An aspheric lens may be the next best choice, but it will only minimize the differences, not completely eliminate them.
The technique of removing inferior and/or superior portions of a lens to aid in lens stabilization is called:
A. Truncation
B. Adding prism
C. Slabbing
D. Tightening
A. Truncation
A change that may result in increased lens movement is:
A. Decreasing the overall diameter
B. Steepening the base curve
C. Using a higher Dk polymer
D. Increasing the overall diameter
A. Decreasing the overall diameter
Which of the following indicates a flat fitting soft contact lens?
A. Circumcorneal indentation
B. Edge stand off
C. Initial comfort for the patient
D. Circumcorneal injection
B. Edge stand off
A patient with entropion and trichiasis is getting inferior punctate staining and discomfort. What contact lens option would be best for this patient?
A. Therapeutic bandage lens
B. gas permeable
C. Conventional daily wear soft lens
D. Toric soft lens
A. Therapeutic bandage lens
A therapeutic bandage lens would be the best choice. Most lenses that are designed as bandage lenses, allow the patient to wear the lens on a continuous, overnight basis. While the other choices may also work, they may not be the best choice. Rigid lenses, because they are smaller, may not give enough coverage. Conventional daily wear and toric soft lenses are not as good if the patient needs to sleep with the lenses.
Which of the following are visual systems used by gas permeable bifocal lenses?
A. Translating and hyperopic
B. Simultaneous and instantaneous
C. Simultaneous and alternating
D. Truncated and prism ballasted
C. Simultaneous and alternating
The two visual systems utilized by rigid gas permeable bifocals are simultaneous and alternating. With simultaneous vision systems, the retina receives both near and far images at the same time. Concentric and aspheric bifocal lens designs utilize simultaneous vision principles. With alternating vision systems, the lens will move on the eye, delivering the focal length that is in front of the pupil as the lens translates or moves on the eye. Segmented bifocal lens designs fall into this category.
Which term refers to a swollen meibomian gland in the lid?
A. Xanthelasma
B. Melanoma
C. Chalazion
D. Hordeolum
C. Chalazion
Lagophthalmos is:
A. Incomplete eyelid closure
B. Drooping eyelids
C. Outward turning of the eyelid
D. Inward turning of the eyelid
A. Incomplete eyelid closure
The average HVID for a patient is:
A. 15 seconds
B. 44.00 diopters
C. 11.5 mm
D. 0.9 %
C. 11.5 mm
When measuring the cornea of a patient who has had LASIK surgery for myopia correction, a range extension lens has been used on the keratometer. The resulting drum reading is 38.00 D spherical. Which of the following is closest to the patient’s actual keratometer measurement?
A. 32.00 D
B. 38.00 D
C. 44.00 D
D. 47.00 D
A. 32.00 D
By applying a -1.00 D lens to the aperture of the keratometer, the range of the instrument can be extended from 36.00 D down to 30.00 D. Six diopters should be subtracted from the actual drum reading to arrive at the patient’s estimated keratometric value. The opposite can be achieved by placing a +1.25 D lens to the keratometer to extend the range upward from 52.00 D to 61.00 D. In this case, adding 9.00 D to the results will give the contact lens professional an approximate reading.
A soft lens patient presents with symptoms of burning, stinging, dryness, limbal to limbal SPK. The most likely cause is:
A. GPC
B. Epithelial splitting
C. Solution sensitivity
D. Three and nine staining
C. Solution sensitivity
Solutions can easily be the cause of burning, stinging, dryness and limbal to limbal superficial punctate keratitis. To rule the patient’s solutions out, a change in the care products can be made to see whether the symptoms persist. If the patient is wearing conventional soft lenses and does not replace them on a frequent basis, this should be attempted with a new pair of contact lenses as older lenses may harbor some of the preservatives to which the patient is sensitive.
The general rule of thumb for selecting the diameter of a soft contact lens is:
A. 3 mm less than the HVID
B. 2 mm larger than the HVID
C. 1 mm larger than the HVID
D. The same size as the HVID
B. 2 mm larger than the HVID
The general rule of thumb is to fit a soft contact lens 1 mm larger on each side of the HVID (or 2 mm in total). This will allow the lens to cover the corneal surface, vault the limbus and extend out onto the sclera. While every contact lens professional may follow a slightly different guideline, this standard has been accepted throughout the industry for many years and tends to be the average choice of many fitters.
Vertical striae in the cornea of a soft contact lens wearer is most likely the result of:
A. A high water content lens
B. A loosely fitting soft lens
C. Corneal swelling
D. Giant papillary conjunctivitis
C. Corneal swelling
The loss of superficial epithelium results in pain because it:
A. Exposes the nerve endings
B. Scars the stroma
C. Decreases the tear reflex
D. Decreases the blood supply
A. Exposes the nerve endings
What condition is marked by a thinning and cone-shaped protrusion of the central cornea?
A. Keratitis sicca
B. Bullous keratopathy
C. Keratoconus
D. Keratomileusis
C. Keratoconus
- Fine, diffuse limbus-to-limbus punctate staining and scleral injection may be caused by:
A. Mechanical trauma
B. Dimple veiling
C. Sensitivity to preservatives in care products
D. Poor insertion or removal technique
C. Sensitivity to preservatives in care products
SPK (superficial punctate keratitis) caused by solution sensitivity is usually diffuse because the chemicals in the offending solution come in contact with the entire cornea. Mechanical trauma may take the form of foreign body tracks, swirl patterns or arcuate staining from a poor edge, poor blinds, or deposits on the lens. Dimple veiling is the term used for tiny air bubbles that are trapped under a rigid lens that is not fitting properly. Central dimples indicate an excessively steep lens to cornea relationship. Bubbles in the periphery indicate that the lens is too flat. A poor insertion or removal technique may result in an arcuate impression of the lens edge where it hits the cornea, or sector staining in those portions of the cornea that are pinched during soft lens removal.
Mechanical injury to the cornea will not result in scar formation provided:
A. The stroma was affected
B. Bowman’s membrane was not affected
C. Bowman’s membrane was affected
B. Bowman’s membrane was not affected
The cornea is comprised of five layers: epithelium, Bowman’s membrane, stroma, Descemet’s layer and endothelium. The corneal epithelium is the only layer that can regenerate cells if they become damaged. If Bowman’s membrane is compromised through injury, it will result in scarring.
A gas permeable lens wearer is in for a six month, contact lens check up. The patient has had no previous history of 3&9 o’clock staining, but on this visit there is arcuate shaped area punctate staining in the 9 o’clock area. What should the examiner suspect is the cause?
A. Lens binding
B. Well-blended peripheral curves
C. Optical zone too small
D. Excessively high edge lift
A. Lens Binding
One of the classic signs of lens binding is an arcuate shaped stain when no previous staining was evident. Even if the lens is moving well at the time of the check up, lens binding maybe the cause. You may have to see the patient at a later time of the day to see the binding. If it is an extended wear RGP wearer, see them in the morning for their exam.
Vascularized Limbal Keratitis is usually caused by:
A. Dry eye syndrome
B. Allergic reaction to solutions
C. Mechanical irritation
D. Excessive exposure to ultraviolet radiation
C. Mechanical irritation
Vascularized Limbal Keratitis (VLK) is believed to be caused predominantly by large diameter rigid gas permeable lenses with low edge lifts. These lenses chaff away at the epithelium in the limbal area along the three and nine oâclock areas. The tear film in the area may also be altered from this traumatic mechanical effect. This all may compound to set in motion the vasogenic response known as VLK.
A translating bifocal wearer complains of blur at distance. Upon slit lamp exam, you notice the bifocal segment bisects the pupil. In order to improve this situation, you should:
A. Increase the seg height
B. Decrease prism ballast
C. Decrease truncation
D. Decrease seg height
D. Decrease seg height
Decreasing the height of the bifocal segment is the only option that will drop the seg and alleviate the visual confusion caused by the segment bisecting the pupil. All of the other options will move the bifocal segment further up into the line of vision.
Dimple Veil is:
A. Pooling of fluorescein caused by trapped air bubbles behind the lens
B. Not truly “staining,” as the epithelial surface is not broken
C. Caused by a lens to cornea relationship that is too steep
D. All of the above
D. All of the above
“SEAL” is a condition that involves:
A. A lesion in the inferior cornea
B. A lesion in the superior cornea
C. The corneal endothelium
D. Loss of central vision
B. A lesion in the superior cornea
“SEAL” stands for Superior Epithelial Arcuate Lesion and is characterized by an epithelial lesion of 1 to 3 mm. It is typically 1 mm from the superior limbus, arcuate in shape and parallel to the limbus. Found among soft lens wearers, it is generally considered to be the result of the soft lens that does not flex enough to conform to both the flat sclera and steeper cornea. The upper lid rubs the lens into the superior cornea, causing the epithelium to split. Discontinuing lens wear until the condition resolves and then refitting with a different soft lens design will solve the problem.
Soft lens induced limbal epithelial hypertrophy usually clears in:
A. 3 to 5 days
B. 1 month
C. 2 months
D. 3 months
A. 3 to 5 days
Limbal epithelial hypertrophy is a change in the peripheral cornea due to a tightly fitting soft contact lens. Clinical findings include a wrinkled or furrowed pattern outside of the limbal area. This is best viewed with the application of fluorescein. Once the lens is removed, the condition typically resolves itself within 3 to 5 days. It is then best managed by refitting the patient with a more loosely fitting soft lens.
Ectropion is:
A. Outward turning of the eyelid
B. Inward turning of the eyelid
C. Inward turning of the eyelashes
D. Incomplete eye closure
A. Outward turning of the eyelid
Arcus senilus is caused from:
A. An infection
B. Infiltrates
C. Fat deposits in the stroma
D. Keratoconus
C. Fat deposits in the stroma
A positive Munson’s sign is a classic sign of what condition?
A. Blepharitis
B. Glaucoma
C. Keratoconus
D. Keratitis Sicca
C. Keratoconus
Name the area of the eye that lies behind the cornea and in front of the crystalline lens and is filled with aqueous fluid.
A. Anterior Chamber
B. Retina
C. Vitreous
D. Choroid
A. Anterior Chamber
Which of the following eye conditions may require a cosmetic painted iris contact lens?
A. Aniridia or iridectomy
B. Iritis or rubeosis
C. Iridectomy or uveitis
D. Aniridia or rubeosis
A. Aniridia or iridectomy
Aniridia and an iridectomy represent one natural and one surgical condition respectively that result in the total or partial absence of the iris. Since the iris is responsible for controlling the amount of light that enters the eye, when part or all of it is missing, the patient suffers from a great deal of photophobia. A painted iris contact lens will help shield the eye from excessive amounts of light.
An RGP patient comes in for their first recheck appointment after receiving their new lenses. They have no complaints. Upon fluorescein examination, you notice some central round areas of “staining”. Upon removal of the lens and re-examination in a few minutes, the “stains” are gone, but depressions are still apparent in the area. After a few minutes longer, these depressions are also gone. This patient has exhibited:
A. SPK
B. Toxic reaction to solutions
C. Dimple Veil
D. Corneal abrasion
C. Dimple Veil
To decrease the sagittal depth of a gas permeable contact lens you can: 1. Steepen the base curve 2. Flatten the base curve 3. Increase the overall diameter 4. Decrease the overall diameter
A. 1 and 4
B. 1 and 3
C. 2 and 3
D. 2 and 4
D. 2 and 4
Flattening the base curve of the lens and decreasing the overall diameter will both decrease the sagittal depth relationship of the contact lens. By combining both of these factors, the impact will be the increased. Steepening the base curve and increasing the overall diameter of the lens will increase the sagittal depth.
Placido’s Disk may be used to evaluate:
A. The base curve of a hydrogel lens
B. The base curve of a rigid lens
C. The amount of corneal cylinder
D. The apex location of keratoconus
D. The apex location of keratoconus
Corneal edema, sensations of soreness, injection, foggy vision and ghost images usually indicate:
A. A tight fitting lens
B. Excessive lens movement
C. Decentration and corneal exposure
D. A lens that is too small and too flat
B. Excessive lens movement
A lens that prevents tear exchange and elimination of corneal debris and metabolic waste products may cause corneal edema, sensations of soreness, injection, foggy vision and ghost images.
The Schirmer II test uses anesthetic to:
A. Control reflex tearing
B. Dilate the pupil
C. Constrict the pupil
D. Increase the tear flow
A. Control reflex tearing
An RGP lens that decenters laterally is most likely fit on a cornea exhibiting:
A. With-the-rule astigmatism
B. Against-the-rule astigmatism
C. Oblique astigmatism
D. Irregular astigmatism
B. Against-the-rule astigmatism
The basement membrane of the corneal endothelium is known as:
A. Bowman’s membrane
B. The anterior chamber
C. Guttata
D. Descemet’s membrane
D. Descemet’s membrane
Descemet’s membrane is a condensation of collagenous protein and is 2 - 3 microns thick in newborns. It increases in thickness over time to 5 - 7 microns centrally and 8 - 10 microns peripherally.
The basement membrane of the corneal endothelium is known as:
A. Bowman’s membrane
B. The anterior chamber
C. Guttata
D. Descemet’s membrane
D. Descemet’s membrane
Which of the following conditions is characterized by superior bulbar conjunctival hyperemia, punctate staining of the superior cornea and limbus, mild superior tarsal papillary hypertrophy, grayish-white sub-epithelial and intraepithelial opacities and superior vascularization of the cornea?
A. Superior epithelial arcuate staining
B. Superior limbic keratoconjunctivitis
C. Giant papillary conjunctivitis
D. Vernal keratoconjunctivitis
B. Superior limbic keratoconjunctivitis
Superior limbic keratoconjunctivitis (SLK) is characterized by superior bulbar conjunctival hyperemia, punctate staining of the superior cornea and limbus, mild superior tarsal papillary hypertrophy, grayish-white sub-epithelial and intraepithelial opacities and superior vascularization of the cornea. The cause of SLK is not fully understood, but solution hypersensitivity should be strongly suspected in these cases. Superior epithelial arcuate staining (SEAL) does not impact the bulbar conjunctiva nor the tarsal conjunctiva. It also does not result in opacities or vascularization of the cornea. Giant papillary conjunctivitis and vernal keratoconjunctivitis affect the tarsal conjunctiva only.
The primary source of oxygen to the anterior cornea in the closed eye state is the:
A. Atmosphere
B. Aqueous humor
C. Limbal vasculature
D. Palpebral conjunctival vasculature
D. Palpebral conjunctival vasculature
Hemoglobin delivers oxygen to the anterior cornea by diffusion from the palpebral conjunctiva during the closed eye state. The atmosphere is responsible for the majority of oxygen to the anterior cornea during the open eye state. The aqueous humor supplies limited amount of oxygen to the posterior cornea and the limbal vessels supply a small amount to the very periphery of the cornea
A subconjunctival hemorrhage:
A. Should be referred to a medical doctor as soon as possible
B. May be sight threatening
C. Will resolve itself in a few days without treatment
D. Should be drained
C. Will resolve itself in a few days without treatment
Subconjunctival hemorrhages are much more frightening in appearance than they are in reality. If a blood vessel in the conjunctiva leaks or is disrupted, a small pooling of blood may form underneath the conjunctiva. The blood will appear bright red and may continue to spread below the conjunctiva after it first is formed. However, within a few days, the blood will be absorbed again and the hemorrhage will clear. These small hemorrhages typically occur spontaneously without the presence of any trauma. It is important to differentiate between a subconjunctival hemorrhage and a hyphema. With a hyphema, blood is leaked within the eye typically after a severe trauma or injury to the eye. Referral to an eye doctor is recommended as the risk of secondary glaucoma or a rebleed is heightened.
Which type of corneal astigmatism is most often represented on an advanced keratoconic cornea?
A. With-the-rule
B. Against-the-rule
C. Irregular
D. Internal
C. Irregular
Keratoconic corneas most often display irregular astigmatism. In some cases, particularly early in the condition, the cornea may have a definite with- or against-the-rule orientation and there may even be an internal component. However, as the condition advances, a more irregular topography evolves. It is this irregular surface that challenges the vision of the patient. Since the surface does not conform to the “normal” or “regular” meridional shape, it becomes more and more difficult to find the true amount or axis of the astigmatism. Patients with severe irregular astigmatism can hope for their best vision through spherical oxygen permeable lenses. This spherical surface re-creates a regular surface for the light rays to enter, improving and enhancing vision.
Foreign body tracks are best viewed using:
A. Fluorescein and a blue cobalt filter
B. A handheld loupe
C. White light and retro illumination
D. Fluorescein and a green red-free filter
A. Fluorescein and a blue cobalt filter
Particles or debris that become trapped between the posterior surface of a contact lens and the anterior surface of the cornea may leave behind small foreign body tracks that can be viewed with the slit lamp using fluorescein and a blue cobalt filter. The use of a yellow Wratten filter will further enhance the presence of these small tracks left behind by the foreign body. A handheld loupe is useful for examining the surface of a contact lens, but is limited in its ability to view the cornea.
The majority of the refracting power of the eye is found on the corneal surface. Which of the following provides the bulk of the remaining refractive power to the eye?
A. Retina
B. Vitreous fluid
C. Aqueous fluid
D. Crystalline Lens
D. Crystalline Lens
- What is the term for a depressed area on the cornea, which is generally found adjacent to an elevated area?
A. Dellen B. Pinguecula
C. Pterygium D. Nevus
A dellen can be defined as a depressed area on the cornea, which is generally found adjacent to an elevated area of the cornea. A pinguecula is an elevated area found on the bulbar conjunctiva. A pterygium is also an elevated area of growing membrane that may extend from the sclera onto the cornea. A nevus is a congenital pigmented area found on the iris or the sclera but which has no elevation.
When viewing a corneal map, the meridian represented by warm colors (red, orange, yellow) denotes which area of the cornea?
A. Flattest B. Steepest
C. Highest D. Lowest
The answer to Question 84 is B.
The warm colors of a corneal map represent the steepest or most curved areas of the cornea. While in a keratoconus map this may also represent the area of the cornea that is “highest”, the warm colors represent degree of curve, not height. In a cornea that exhibits a with-the-rule orientation, the warm colors are lined up vertically. When the warm colors are lined up horizontally, they exhibit an against-the-rule orientation.
. A coloboma may be present in the:
A. Iris B. Retina
C. Eyelid D. All of the above
The answer to Question 85 is D.
A coloboma is an abnormality that may be found in any of the structures of the eye, usually in the lower half, due to an abnormal development during gestation.
- Which of the following will most likely provide the best vision for a patient following penetrating keratoplasty?
A. RGP lenses B. Soft toric lenses
C. Daily disposable lenses D. Eyeglasses
The answer to Question 86 is A.
Following penetrating keratoplasty (corneal transplant), a patient will most likely get their best vision with the use of a rigid gas permeable lens. Irregular astigmatism or “graft tilt” are possible following surgery, resulting in poor best corrected vision. Not only will the rigid plastic correct the patient’s vision optimally, but also the increased oxygen that is available to the cornea will reduce the threat of neovascularization.
Invasion of the peripheral cornea by the infiltration and formation of new blood vessels is also called:
A. Pterygium B. Pannus
C. Pinguecula D. Ptosis
The answer to Question 83 is B.
Pannus may be described as an invasion of the peripheral cornea by the infiltration and formation of new blood vessels. These are typically fine, thin vessels that progress slowly and are a result of some type of corneal compromise such as hypoxia, allergic reaction, trauma or disease. While a pterygium is vascularized, it is comprised primarily of a membrane that extends from the conjunctiva to the cornea. A pinguecula is an elevation found on the nasal or temporal bulbar conjunctiva and does not extend onto the peripheral cornea. Ptosis is a drooping of the upper eyelid.
What is the most effective way for a patient to remove protein from the surface of an RGP lens?
A. Polishing B. Wetting and soaking solution
C. Toothpaste D. Enzyme cleaner
The answer to Question 87 is D.
Protein is found in a patient’s tear and accumulates on the lens during wear. The amount of deposition is dependent upon the patient’s tear make-up and the material used for the lens. Normally, a fluoro-silicone acrylate lens will be more protein resistant than a silicone acrylate. Removing protein is most effectively done by the patient by soaking the lens in an enzyme cleaner on a consistent basis. While polishing the lens will also remove protein, it is less convenient for the patient because it involves a visit to the eye care professional’s office.
A patient present in your office with a whitish, speckled area on the cornea from three to nine o’clock. This patient may be presenting with:
A. Cataracts B. Glaucoma
C. Band keratopathy D. Keratitis
The answer to Question 88 is C.
Band keratopathy is a calcium build-up in Bowman’s layer. It may extend across the cornea nasally to temporally. It can result from chronic uveitis or a corneal inflammatory disease. An ophthalmologist can treat it by removing the epithelium and treating the affected area with an EDTA solution to dissolve the calcium.
The appearance of a dendritic lesion is a classic sign of:
A. Herpes simplex keratitis B. Glaucoma
C. Terrien’s marginal dystrophy
The answer to Question 89 is A.
The presence of a dendrite is a classic sign of the herpes simplex virus. The patient will most likely also present with pain, redness, sensitivity to light, foreign body sensation and a watery discharge. The diagnosis becomes much clearer when the distinctive dendritic lesions are visible. If left untreated, these lesions can cause scarring which can affect the patient’s long-term vision.
A corneal map shows a steepening of the cornea at the inferior limbus, a high degree of central against-the-rule astigmatism and a distinctive “butterfly” appearance. This patient most likely has:
A. Keratoconus B. Pellucid Marginal Degeneration
C. Hydrops D. Corneal molding
The answer to Question 90 is B.
Pellucid marginal degeneration is a non-infectious, non-inflammatory condition in which the steepening/thinning of the cornea is located with 1-2 mm of the inferior limbus. This results in a classic “butterfly” pattern when corneal maps are performed. Keratometry may typically reveal a flatter than average central reading with a significant against-the-rule orientation. The thin, steepened area of keratoconus is located in the inferior paracentral area of the cornea.
In response to trauma, infection, inflammation or hypoxia, the cornea may receive extra oxygenation and nutrition from the:
A. Limbal blood vessels B. Palpebral blood vessels
C. Aqueous humor D. Corneal blood vessels
The answer to Question 91 is A.
When the cornea is distressed, a normal reaction is for the limbal blood vessels to respond by beginning to encroach upon this normally avascular tissue. Unfortunately, while this does provide extra oxygen and nutrients to the cornea in its time of need, it also encourages blood vessels into an area where they do not belong. Neovascularization of the cornea is a sign that the cornea is in distress.
Corneal hydrops could be expected to be seen in patients with:
A. Keratoconus B. Arcus senilus
C. Glaucoma D. Cataracts
The answer to Question 92 is A.
Corneal hydrops are caused by a rupture in Descemet’s membrane. The aqueous expands into the stroma, causing marked swelling and corneal thickening. In most cases, hydrops resolve without surgical intervention, though there may be some residual scarring.
Which of the following conditions would most likely result in irregular corneal astigmatism?
A. Corneal laceration B. Keratoconus
C. Herpes simplex keratitis D. All of the above
The answer to Question 93 is D.
Irregular corneal astigmatism occurs whenever the cornea loses its symmetrical shape as it would with a corneal laceration (shown in this photo), trauma, surgery, keratoconus, pellucid marginal degeneration, herpes simplex keratitis, corneal dystrophies and other conditions that affect the cornea in a non-symmetrical manner.
This furrow pattern found near the corneal limbus in the presence of fluorescein is a traditional finding in which of the following conditions?
A. Superior epithelial arcuate lesion B. Superior limbic keratoconjunctivitis
C. Limbal epithelial hypertrophy D. Arcus senilus
The answer to Question 94 is C.
Limbal epithelial hypertrophy is a localized peripheral corneal change that most often occurs with the use of thick soft lenses that exhibit poor movement on the blink. Patients are most often asymptomatic, but they may notice that comfort has decreased or they have a slight foreign body sensation while wearing the lenses. Discontinuing lens wear until the condition resolves and then refitting the patient into a lens that has increased lens movement will solve the problem.
Which of the following would not be considered a traditional classification for keratoconus?
A. Nipple B. Oval
C. Spherical D. Globus
The answer to Question 95 is C.
The traditional classifications of keratoconus include the nipple, oval and globus cones. The smallest of the classifications is the nipple cone, followed by the oval and globus, which may take up the majority of the patient’s cornea as is depicted in this picture. This red fundus reflex shows the base of the cone of a dilated patient.
This classic swirl staining found on a patient with keratoconus is indicative of:
A. Dimple Veil B. A flat fitting RGP lens
C. A steep fitting RGP lens D. Corneal hydrop
The answer to Question 96 is B.
When a keratoconus patient presents with a classic swirl staining pattern, it is indicative of a flat fitting RGP lens. This is a result of the flat lens being rotated nasally as the patient blinks and rubbing against the apex of the cone. Even if the patient is asymptomatic (which they most usually are), the fit should be re-evaluated and improved.
A patient wearing the lens shown in the photo is most likely being treated for
A. Color deficiency B. Keratoconus
C. Snow blindness D. Grave’s disease
The answer to Question 97 is A.
The X-chrome lens, pictured here, is a red tinted lens that is worn on a patient’s non-dominant eye to help correct for specific types of color blindness. The results are not always guaranteed, resulting in the rare use of this lens.
One cause of corneal desiccation along the horizontal meridian of a gas permeable lens wearer may be:
A. A loose lens fit along the horizontal meridian B. Against-the-rule corneal astigmatism
C. A tight lens fit along the horizontal meridian D. Epiphora
The answer to Question 98 is C.
When the lens to cornea relationship along the horizontal meridian results in a lack of tear film in that area, desiccation can occur. This can occur when the lens to cornea relationship is too steep in this area, or even when there is excessive edge lift that inhibits the ability of the eyelid to spread tear film on the cornea. This is more commonly referred to as three and nine o’clock staining based on the location of the staining. The reason that the staining occurs in this meridian is because a with-the-rule cornea is flattest along the horizontal (three and nine o’clock) meridian and it comes into contact with the lens in this meridian. Patients whose corneas have an against-the-rule orientation would most likely not be bothered by rubbing in both the three and nine o’clock areas since the lens is closest to the cornea in the vertical meridian on these corneas. Epiphora is excessive tearing.
A condition in which the ocular image of an object as seen by one eye differs so much in size or shape from the image seen in the other eye that the two images cannot be fused into one image is called:
A. Aniridia B. Amblyopia
C. Anophthalmia D. Aniseikonia
The answer to Question 99 is D.
Aniseikonia occurs when the eye cannot fuse two images because they are so different in size or shape between the two eyes. This may occur from a significant difference in Rx between the two eyes. Amblyopia, a loss of vision without any apparent disease of the eye, may result if aniseikonia goes uncorrected in children since the optic nerves won’t receive usable images and the nerve may simply become unable to function properly. Aniridia is the congenital absence of the iris. Anophthalmia is the absence of a true eyeball.
Corneal molding may occur with the use of:
A. Fluoro-silicone acrylate RGP lenses B. Silicone acrylate RGP lenses
C. Soft lenses D. All of the above
The answer to Question 100 is D.
Any contact lens material, PMMA, RGP and soft, has the potential to create a situation of corneal molding or warpage.
What is the most common RGP Complication?
Corneal Desiccation (Dry Eye)
What does Corneal dessication Cause?
Peripheral Staining
Dellen
Bound Lens
Usually Tear Problems
What causes peripheral staining ?
Thick lens edge
too much or too little edge lift
inadequate tear volume
Inferior riding lens
Small amount is ok
3-9 staining may also be associated with…
Bleph, mebomianitis, meds, inadequate tears
