Exam (elaborations)
NCLE Basic Exam Study Guide
- Module
- NCLE Basic Exam Study Guide
- Institution
- NCLE Basic Exam Study Guide
NCLE Basic Exam Study Guide
[Show more]
Content preview
NCLE Basic Exam Study GuideDiffused Illumination - --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 - --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 - --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 - --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 - --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 - --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 - --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 - --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 - --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 - --Show spherical aberrations
-More useful when assessing visual performance of post refractive patients
-Corneal Topography - Elevation Map - --Shows the difference in the
elevation of the cornea
-Measured in microns
-Corneal Topography - Irregularity Map - --Similar to elevation maps
-Uses best fit toric surface as a reference
-Eliminates any toricity from the eye and displays the elevation differences
-Corneal Topography - Photokeratoscopic Views - -Uses the placido rings
which are reflected onto the eye to subjectively determine the location and
regularity of the rings
-Corneal Topography - Numerical Views - --Arranges individual keratometric
findings to depict curvature readings of the eye
-Extremely useful when fitting specialty contacts
-Corneal topographic software calculates the "average keratometric" value
-Corneal Topography - Keratometry Views - --Represent the keratometric
readings along with the axes of the eye's presumed astigmatism
-Dioptric values define the findings from the center of the cornea to the
periphery
-This view helps the practitioner to quickly determine if corneal astigmatism
is symmetrical
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller Victorious23. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for £10.14. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
62555 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy revision notes and other study material for 14 years now