NCLE Basic Exam Study Guide Questions
With Correct Answers
Diffused Illumination - CORRECT ANSWER✔✔--Uses widest slit, longest aperture
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-Light source positioned at an angle of 40º-50º
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-Used to view overall areas, to observe the ocular adnexa, cornea, sclera, lids,
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conjunctiva, lens surface, and CL fitting characteristics
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Direct Illumination - CORRECT ANSWER✔✔--Most important/useful illumination
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-Light source positioned at an angle of 40º-50º to oculars
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-Light beam and oculars are focused in coincidence on area being evaluated
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-The difference in the illumination is not the angle used, but where the beam is
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directed or focused and the width
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-Varying width and aperture creates different illuminations
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Optic(al) Section - CORRECT ANSWER✔✔--Type of direct illumination that uses a
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narrow beam to create a cross-section of the cornea
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-Used to illuminate and observe individual layers of the cornea and tear film
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-Used to evaluate corneal thickness, thinning, distortions, or depth of a foreign
| | | | | | | | | | | |
body
-Shows corneal-lens relationship
| |
Parallelepiped - CORRECT ANSWER✔✔--Type of direct illumination
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-Uses a 0.5-3.0 mm beam and a 40º-50º angle to create a 3-D cube
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,-Used to assess width, depth, and height of an object within the cornea
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-Useful in observing scars, infiltrates, staining, and the corneal-lens relationship
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Indirect Illumination - CORRECT ANSWER✔✔--Light source is moved out-of-click,
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the beam is 2-3 mm wide and is positioned next to the area being studied
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-Illuminated area is translucent or opaque, allowing for observation adjacent to
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illumination
-Used to observe foreign bodies, corneal nerves, and opacities
| | | | | | | |
-Oscillation of light accentuates details | | | |
Retroillumination - CORRECT ANSWER✔✔--Light source is out-of-click, moved to | | | | | | | | |
the side of the area being observed
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-Using a 1-3 mm beam, the light is reflected off the iris and used to back-light the
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area studied
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-Useful in examining corneal scars, debris, microcysts, scratches on the lens, sub-
| | | | | | | | | | |
epithelial changes, corneal vascularization, diffuse edema, and surface deposits
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Sclerotic Scatter - CORRECT ANSWER✔✔--Uses a focused parellelepiped placed
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out-of-click directed at the limbus | | | |
-Oculars are not used | | |
-The light is dispersed at the limbus, reflected through the cornea, creating a
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circumcorneal halo |
-Used to observe edema, stromal folds, lens deposits, bubbles under the lens,
| | | | | | | | | | | |
lens defects, and scratches
| | |
, Corneal Topography - Axial Map - CORRECT ANSWER✔✔--Most widely
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understood map of the cornea for many CL fitters
| | | | | | | |
-Overall shape of the cornea
| | | |
-Colors relate to steepness/flatness
| | |
-Sagittal reading measures the curvature of the cornea in diopters and is called
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the axial power map
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-Calculates curvature rather than power | | | |
Corneal Topography - Tangential Map - CORRECT ANSWER✔✔--More sensitive
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map of the cornea
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-Calculates corneal curvature based on the tangent to normal
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-Found to be more beneficial in identifying corneal pathology
| | | | | | | |
-Not used as frequently to fit CLs
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Corneal Topography - Refractive Power Map - CORRECT ANSWER✔✔--Show
| | | | | | | | |
spherical aberrations |
-More useful when assessing visual performance of post refractive patients
| | | | | | | | |
Corneal Topography - Elevation Map - CORRECT ANSWER✔✔--Shows the
| | | | | | | | |
difference in the elevation of the cornea
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-Measured in microns | |
Corneal Topography - Irregularity Map - CORRECT ANSWER✔✔--Similar to
| | | | | | | | |
elevation maps |
-Uses best fit toric surface as a reference
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With Correct Answers
Diffused Illumination - CORRECT ANSWER✔✔--Uses widest slit, longest aperture
| | | | | | | |
-Light source positioned at an angle of 40º-50º
| | | | | | |
-Used to view overall areas, to observe the ocular adnexa, cornea, sclera, lids,
| | | | | | | | | | | | |
conjunctiva, lens surface, and CL fitting characteristics
| | | | | |
Direct Illumination - CORRECT ANSWER✔✔--Most important/useful illumination
| | | | | |
-Light source positioned at an angle of 40º-50º to oculars
| | | | | | | | |
-Light beam and oculars are focused in coincidence on area being evaluated
| | | | | | | | | | |
-The difference in the illumination is not the angle used, but where the beam is
| | | | | | | | | | | | | | |
directed or focused and the width
| | | | |
-Varying width and aperture creates different illuminations
| | | | | |
Optic(al) Section - CORRECT ANSWER✔✔--Type of direct illumination that uses a
| | | | | | | | | | |
narrow beam to create a cross-section of the cornea
| | | | | | | |
-Used to illuminate and observe individual layers of the cornea and tear film
| | | | | | | | | | | |
-Used to evaluate corneal thickness, thinning, distortions, or depth of a foreign
| | | | | | | | | | | |
body
-Shows corneal-lens relationship
| |
Parallelepiped - CORRECT ANSWER✔✔--Type of direct illumination
| | | | | |
-Uses a 0.5-3.0 mm beam and a 40º-50º angle to create a 3-D cube
| | | | | | | | | | | | |
,-Used to assess width, depth, and height of an object within the cornea
| | | | | | | | | | | |
-Useful in observing scars, infiltrates, staining, and the corneal-lens relationship
| | | | | | | | |
Indirect Illumination - CORRECT ANSWER✔✔--Light source is moved out-of-click,
| | | | | | | | |
the beam is 2-3 mm wide and is positioned next to the area being studied
| | | | | | | | | | | | | |
-Illuminated area is translucent or opaque, allowing for observation adjacent to
| | | | | | | | | | |
illumination
-Used to observe foreign bodies, corneal nerves, and opacities
| | | | | | | |
-Oscillation of light accentuates details | | | |
Retroillumination - CORRECT ANSWER✔✔--Light source is out-of-click, moved to | | | | | | | | |
the side of the area being observed
| | | | | |
-Using a 1-3 mm beam, the light is reflected off the iris and used to back-light the
| | | | | | | | | | | | | | | | |
area studied
|
-Useful in examining corneal scars, debris, microcysts, scratches on the lens, sub-
| | | | | | | | | | |
epithelial changes, corneal vascularization, diffuse edema, and surface deposits
| | | | | | | |
Sclerotic Scatter - CORRECT ANSWER✔✔--Uses a focused parellelepiped placed
| | | | | | | | |
out-of-click directed at the limbus | | | |
-Oculars are not used | | |
-The light is dispersed at the limbus, reflected through the cornea, creating a
| | | | | | | | | | | | |
circumcorneal halo |
-Used to observe edema, stromal folds, lens deposits, bubbles under the lens,
| | | | | | | | | | | |
lens defects, and scratches
| | |
, Corneal Topography - Axial Map - CORRECT ANSWER✔✔--Most widely
| | | | | | | | |
understood map of the cornea for many CL fitters
| | | | | | | |
-Overall shape of the cornea
| | | |
-Colors relate to steepness/flatness
| | |
-Sagittal reading measures the curvature of the cornea in diopters and is called
| | | | | | | | | | | | |
the axial power map
| | |
-Calculates curvature rather than power | | | |
Corneal Topography - Tangential Map - CORRECT ANSWER✔✔--More sensitive
| | | | | | | | |
map of the cornea
| | |
-Calculates corneal curvature based on the tangent to normal
| | | | | | | |
-Found to be more beneficial in identifying corneal pathology
| | | | | | | |
-Not used as frequently to fit CLs
| | | | | |
Corneal Topography - Refractive Power Map - CORRECT ANSWER✔✔--Show
| | | | | | | | |
spherical aberrations |
-More useful when assessing visual performance of post refractive patients
| | | | | | | | |
Corneal Topography - Elevation Map - CORRECT ANSWER✔✔--Shows the
| | | | | | | | |
difference in the elevation of the cornea
| | | | | |
-Measured in microns | |
Corneal Topography - Irregularity Map - CORRECT ANSWER✔✔--Similar to
| | | | | | | | |
elevation maps |
-Uses best fit toric surface as a reference
| | | | | | |
