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NCLE Study Guide Exam 2024/2025 Questions With Completed & Verified Solutions.
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NCLE Study Guide Exam 2024/2025 Questions With Completed & Verified Solutions.
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NCLE Study GuideCorneal - ANS Most common design for rigid and gas permeable lenses.
The three broad categories of contact lens design - ANS Scleral (haptic), semi scleral,
and corneal lenses
The more common conditions for choosing either smaller or larger contact lens designs
- ANS Smaller lenses are good for milder forms of keratoconus or irregular astigmatism.
Larger lenses are good for advanced keratoconus, pathologically dry eyes, or severe
ocular surface diseases.
All seven names for classes of contact lenses - ANS Bandage lens, cosmetic/theatrical
lens, flexible/prolonged wear lens, gas permeable, hydrophilic, hydrophobic, and
semi-soft lenses
Wetting angle - ANS The angle that the edge of a bead of water makes with the surface
of a material, the smaller the angle the greater the wetting ability.
PMMA: Polymethlmethacrylate
CAB: Cellulose Acetate Butyrate - ANS The two types of rigid lenses.
Bausch and Lomb soft lens - ANS HEMA: hydroxyethlmethacrylate.
9 characteristics of contact lenses to take into account to best advise patients - ANS
Percentage of water content, oxygen permeability, how well the material defends
against deposits, thickness, lens edge, lens color/tint if applicable, design parameters,
length of wear desired, and replacement intervals.
Benefits of soft contact lenses - ANS Comfortable, shorter adjustment period, good for
patients in athletics or patients with minor corrections, and better in environments where
particles would get lodged under a rigid lens.
Allergic responses to silicone hydrogel lenses - ANS Most common complaints that
point towards an allergic reaction is redness, discomfort, itchy eyes, and greater lens
awareness.
,Common contraindications for soft lenses - ANS Visual acuity, absorbing things like
chemicals, germs, oils, but also being able to be dehydrated easier by being in dry
environments. Tainted lenses can also cause ocular diseases, and any irregularities or
bumps on sclera/bulbar conjunctiva would cause issues with soft contacts.
1947 - ANS The year the first all plastic corneal lens was made by K. Touhy.
Significance of the year 1968 relating to CLs regulation - ANS The year the FDA
became involved in regulating contact lenses.
The three layers of the precorneal tear film that make up the acronym LAM - ANS From
outside to in; lipid, aqueous, and mucin.
Bandage Contact Lens - ANS Protects the eye while the healing of corneal disorders
takes place.
Bicurve and tricurve lens design - ANS Bicurve: A pair of blended curves, a primary
base curve and flatter peripheral curve.
Tricurve: Two peripheral curves labeled intermediate curves, both being 1mm flatter
than base curve.
The anterior zone on the edge of a contact lens - ANS Portion of the edge in contact
with the upper lid during a blink cycle.
The posterior zone on the edge of a contact lens - ANS Small reverse curve placed on
the posterior lens surface to flare the edge away from the cornea.
The edge apex of a contact lens - ANS Junction between the anterior and posterior
zones on the edge of a contact lens.
Three things that can be attempted to increase tear exchange in a GP lens - ANS
Reduce overall lens diameter, flatten the peripheral curves, or, decreasing the optic
zone.
Base curve of a contact lens - ANS Central portion of the back surface of a contact lens,
also known as CPC or central posterior curve.
,Rule of thumb for the effect of radius of curvature changes on CL power - ANS Power of
a curve changes by 0.50 diopters, radius of curvature changes by approximately
0.10mm
45 diopters of power is equivalent to this radius - ANS 7.50 mm of radius.
7.50 mm of radius is equivalent to this power - ANS 45 diopters.
Sagittal depth or height - ANS Distance between a flat surface and the back surface of
the central portion of the lens.
Correlation of radius of curvature to sagittal depth - ANS ROC increases, sagittal depth
decreases and vice versa.
Correlation of radius of curvature to base curve in regard to steepness/flatness - ANS
ROC increases, base curve becomes flatter. ROC decreases, base curve becomes
steeper.
Multicurve Lens - ANS Contains a base curve and three or more peripheral curves.
Usually a larger lens.
Truncated lens - ANS A lens that is cut off to form a horizontal base to add stability to a
soft toric lens and to prevent rotation.
Principal Meridians - ANS The meridians of shortest and longest radii which differ by 90
degrees.
Toroid Lenses - ANS Toric lenses with different radii of curvature in each meridian used
to correct astigmatism.
Curve Widths - ANS The width of the CPC, PPC, or IPC.
Spin-Cast Soft Lens - ANS A method of manufacturing soft contact lenses whereby a
liquid material is revolved in a mold at a controlled speed and temperature which
produces the desired curvature, design, and power.
Lathe Cut Soft Lens - ANS A method of manufacturing soft CL a machine lathe is used
to grind lens designs, size and power.
, Small and Large Wetting Angle Properties - ANS Spread evenly over a surface for
small, big has the liquid staying in a droplet shape.
Generally a secondary curve of a rigid contact lens is this much larger than the CPC in
Diopters - ANS 2 to 4 diopters larger.
If a contacts central posterior curve is 7.5 mm in radius of curvature, this is its power -
ANS 45.00 diopters.
A increase in diameter on a contact lens can remedy this problem - ANS Excessive
movement.
When determining contact lens materials, these three things need to be taken into
consideration - ANS Patients working conditions, pre-corneal tear film evaluation, and, if
it will be full time or part time wear.
The gas permeability of a Cellulose acetate butyrate lens is largely dependent on this
trait - ANS Lens thickness.
A RGP lens with a base curve of 7.5 mm is found to be sitting slightly tight, a change in
base curve to this would improve that - ANS 7.55 mm.
The CPC of a rigid contacts lens is held constant while the diameter increases would
result in this. - ANS A tighter fit.
HEMA - ANS An abbreviation commonly used to describe soft lenses.
Amount of gas permeability in a polymethylmethacrylate lens - ANS Almost no gas
permeability.
Shortening the radius of curvature of the CPC of a loose fitting lens does this - ANS
Tightens the fit.
Bicurve rigid contact lenses have common traits such as these - ANS Small and steep,
fit within the interpalpebral fissure limits, and made with narrow peripheral curves.
When the radius of curvature is held constant but the diameter increases, this happens
to the sagittal depth - ANS Sagittal depth increases.
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