Modern Clinical Optometry Volume II

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Modern Clinical Optometry Volume II

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Title: Modern Clinical Optometry Volume II

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Modern Clinical Optometry
AllDocs 2007

Craig Thomas, O.D.
3900 West Wheatland Road
Dallas, Texas 75237
972-780-7199
thpckc_at_yahoo.com

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Medical Eye Care

Professional Services
Diagnostic Tests
Minor Surgical Procedures
Ophthalmic Ultrasound
Laboratory Services

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Diagnostic Tests

Group 1
(1) Refraction
(2) Sensorimotor Examination
Group 2
(1) Computerized Corneal Topography
(2) Specular Endothelial Microscopy
(3) External Ocular Photography

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Diagnostic Tests

Group 3
(1) Retinal Photography
(2) Retinal Scanning Laser
Group 4
(1) Visual Field Examination
(2) Color Vision Examination

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Ophthalmic Ultrasound

A-Scan Ophthalmic Ultrasound
B-Scan Ophthalmic Ultrasound
Corneal Pachymetry
High Resolution Biomicroscopy

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Corneal Topography Primer

The clinical application of Computerized
Corneal Topography is to determine the
physical features and shape of the
anterior surface of the cornea.
The test is indicated in the identification
of deep or superficial corneal disorders
causing (1) irregular astigmatism
(2) visual impairment.

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Examination Technique

Determine test result reliability
(1) Acquisition of high quality image of
the air/pre-corneal tear film interface
(2) Image quality is affected by corneal
disease, the quality of the tear film,
or any corneal deformity secondary
to contact lens wear.

Note To improve image quality, instill one drop
of unpreserved artificial tears into each eye
prior to the image capture process.
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Interpreting the Maps

Determination of Corneal Shape
Assessment is accomplished by interpreting
the color patterns and numeric values
on the topographic map. Cool colors such
as green and blue represent lower corneal
curvatures - while warmer colors such as
yellow and red suggest higher corneal
curvatures.

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Interpreting the Maps

Axial Map
The standard topographic map of corneal
curvature using an axial radius of curvature.
The map is created by combining colors and
patterns to represent corneal curvature.
It shows corneal curvature in diopters, and
is used to describe the overall corneal shape.

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Interpreting the Maps

Tangential Map
This topographic map also assesses corneal
shape but, it is more sensitive at
detecting the precise location of a specific
defect. Because it is not axis dependent,
this type of evaluation is better for patients
with keratoconus, contact lens wearers, and
patients with irregular astigmatism.

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Interpreting the Maps

Determination of Corneal Shape
(1) Round Corneal Shape
(2) Oval Corneal Shape
(3) Astigmatic Corneal Shape
- regular astigmatism
- irregular astigmatism

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Interpreting the Maps

Round Corneas
The color patterns on round corneas can
present as concentric rings. These rings,
radiating from the center of the cornea
to the limbus, characterize the normal
flattening that occurs in the corneal
periphery. Round corneas are present
in 23 of the general population.

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Round Cornea
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Interpreting the Maps

Oval Corneas
The color patterns form ellipsoid
waves that radiate from the center
of the cornea to the limbus.
These oval corneas are present in
21 of the general population.

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Oval Cornea
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Interpreting the Maps

Astigmatic Corneas
Corneal astigmatism is expressed in two forms
(1) Regular Astigmatism
(2) Irregular Astigmatism
In corneal astigmatism, the color patterns
of a topography map form a bowtie
configuration that can be used to determine
the regularity of the astigmatism.

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Regular Limbal Astigmatism
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Interpreting the Maps

Regular Astigmatism
Patients with regular astigmatism can have
limbal astigmatism or central astigmatism.
In limbal astigmatism, the bowtie-
shaped color pattern extends across the
cornea. This type of corneal astigmatism is
likely to be responsible for a corresponding
amount of refractive astigmatism.

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Regular Central Astigmatism
Also known as Axial Astigmatism
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Interpreting the Maps

Regular Astigmatism
In central astigmatism, most of the
bowtie-shaped color pattern occurs within
the pupillary region. This type of corneal
astigmatism can be underestimated by
traditional keratometry readings and may
not match the refractive astigmatism.

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Interpreting the Maps

Irregular Astigmatism
Irregular astigmatism can be
expressed in three forms
(1) Asymmetric
(2) Non-Orthogonal
(3) Unspecified

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Asymmetric Irregular Astigmatism
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Interpreting the Maps

Irregular Astigmatism
In asymmetric irregular astigmatism,
the two ends of the bowtie-shaped color
pattern are of a different size and color.
This can be clinically significant if there
is more than a one diopter difference in
the amount of astigmatism on each end
of the bowtie.

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Keratoconus
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Pellucid Marginal Degeneration
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Non-Orthogonal Irregular Astigmatism
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Interpreting the Maps

Irregular Astigmatism
In non-orthogonal irregular astigmatism,
the bowtie-shaped color pattern is bent
instead of being straight.
Corneal dystrophies and other corneal
diseases can produce non-orthogonal
astigmatism.

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Interpreting the Maps

Unspecified Irregular Astigmatism
In unspecified astigmatism, there may be
no bowtie-shaped color pattern displayed
by the corneal topographer. The corneal
irregularities may have a random distribution
with no specific pattern. With this clinical
presentation, focal changes of more than
1.5 diopters could be clinically significant.

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Unspecified Irregular
Astigmatism
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Interpreting the Maps

Corneal Shape Anomalies
(1) Abnormal Shape Symmetry
(2) Areas of Significant Relative Steepness
(3) Areas of Significant Relative Flattening
(4) Abnormal Corneal Eccentricity

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Interpreting the Maps

Corneal Shape Symmetry
The shape of the superior cornea should be
compared to the shape of the inferior cornea,
just as the shape of the nasal cornea should
be compared to the temporal cornea.
Any asymmetry above 1.5 diopters
could be clinically significant.

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Abnormal Shape Symmetry
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Specular Microscopy Primer

The clinical application of specular
endothelial microscopy is to enable the
status of the corneal endothelium
to be obtained by visual observation.
The test is indicated in the diagnosis
and treatment of any eye disease, eye
injury, or ocular condition that can result
in corneal endothelial cell damage.

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Modern Specular Microscope
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Clinical Indications

Many eye diseases affect the corneal
endothelium. Significant alterations
in endothelial function (endotheliopathy)
can result in any or all of the following
(1) Blurred Vision
(2) Fluctuating Vision
(3) Permanent Visual Impairment

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Risk Factors for Corneal
Endotheliopathy

Advancing Age
Corneal Disease
Ocular Disease
Systemic Disease
Ocular Surgery
Ocular Injury
Contact Lens Wear

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Specular Microscopy

Endothelial cell damage is represented by the
following
(1) Reductions in endothelial cell density
(2) Morphological changes such as
polymegathism and pleomorphism
(3) The appearance, enlargement, or
coalescence of corneal guttata

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Specular Microscopy
Photomicrographs
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Specular Endothelial Microscopy Corneal
Endothelial Dystrophies

Corneal guttata consists of abnormal
outgrowths of Descemets membrane that
squeeze between the endothelial cells.
They are apparently formed as endothelial
cell density decreases and the barrier
function of the endothelium is compromised.
Guttata appear as dark spots in the normal
hexagonal mosaic pattern of the cells.

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Specular Endothelial Microscopy
Corneal Guttata
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Specular Endothelial Microscopy Corneal
Endothelial Dystrophies

Guttata represent a generalized endothelial
dysfunction. If they are present in large
numbers, guttata may lead to stromal
edema and an accompanying decrease in
vision. Visual acuity can also be affected if
the guttata are concentrated heavily in the
axial region of the cornea.

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Corneal Physiology

Deturgescence is the state of relative
dehydration maintained by the normal
intact cornea which enables it to remain
transparent. The endothelium is the layer
of the cornea responsible for this function.
The functional limit for maintaining
deturgescence is a cell count of 7001000.

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B-Scan Ophthalmic Ultrasound Clinical
Applications

Ultrasound is the term for sound waves
projected at a very high frequency.
(over 20,00 kHz)
B-Scan Ophthalmic Ultrasound uses
transducer scanning and electronic
processing to image the internal
structures of the eye and orbit.

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Modern Transducer
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transducer scanning and electronic prossesing,
images the internal structures of the body.
When used in this manner, the examination
technique is known as diagnostic ultrasound.
B-Scan Ophthalmic Ultrasound is used to image
the internal structures of the eye and orbit.

Clinical Indications

B-Scan ophthalmic ultrasound is used
when clouding of the ocular tissues
prevents proper visualization and
examination of the structures of the eye.
B-Scan ophthalmic ultrasound is used to
determine the composition and contours
of ocular and orbital structures.

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Clinical Indications

Patients with dense cataracts or corneal
opacities that prevent good visualization
of the retina.
Patients with vitreous floaters, deposits,
hemorrhages, and/or degenerations.
Patients with signs and/or symptoms of
retinal detachment.

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Interpreting the B-Scans
Dense Cataract
Retina Grossly Normal
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Interpreting the B-Scans

Asteroid Hyalosis
Asteroid Hyalosis
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Interpreting the B-Scans
Retinal Detachment
Retinal Detachment
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VF defect from retinal detachment
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Case Report 1

A 62-year old Black woman presented for an
eye examination with a chief complaint of
elevated intraocular pressure. The patient
was referred by another optometrist that
same day by telephone. The referring
optometrist had measured the elevated
intraocular pressures and was requesting
an emergency appointment with me.

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Medical Eye Examination Service
Components

IOP OD 36 OS 24 Tonopen
_at_ 415
pm
Biomicroscopy All structures normal
Ophthalmoscopy
(1) Asymmetric cupping
(2) Vertical elongation of right optic cup
OD 0.4 h OS 0.2 h
0.6 v 0.2
v

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Case 1 Open Angle Glaucoma
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Medical Eye Examination
Clinical Diagnosis

Determining a clinical diagnosis of
glaucoma only leads to other questions.
Question 1 What type of glaucoma?
Question 2 How bad is the glaucoma?
Question 3 How are you going to treat?
The answers require a Physical Diagnosis.

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Initiation of Diagnostic
Treatment Program

Refraction OD 1.50 sphere 20/25
OS 1.50 sphere
20/20
Scanning Laser Polarimetry
(1) Severe fallout of retinal nerve fiber
layer Right Eye
(2) Abnormal inter-eye symmetry
NFI 62 on the Right Eye
NFI 27 on the Left Eye

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Initiation of Diagnostic
Treatment Program

Visual Field Examination
(1) Moderate reduction in retinal sensitivity
Right Eye Mean Deviation 7.58 DB
(2) Mild reduction in retinal sensitivity
Left Eye Mean Deviation 3.54 DB
(3) Paracentral scotomas Right Eye
(4) Poor reliability Both Eyes

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Initiation ofDiagnosis Treatment
Program

High Resolution Biomicroscopy
(1) Normal iris configuration Both Eyes
(2) Open angles Both Eyes
(3) Thin corneal thickness Both Eyes

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Initiation of Diagnostic
Treatment Program

Specular Endothelial Microscopy

(1) Mild corneal endothelial dystrophy
Both Eyes
(2) No severe morphological changes to
the endothelial cells or corneal edema
from long-term exposure to elevated
intraocular pressure.

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Iniatition of Diagnostic
Treatment Program
Specular Photomicrographs
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Initiation of Diagnostic
Treatment Program

Serial Tonometry
Medical treatment of acute elevation
of intraocular pressure.
OD OS Treatment
36 24 _at_ 415 pm 1 gt Timolol 0.5 _at_ 420
pm
27 15 _at_ 558 pm 250 mg Diamox _at_ 440
pm
19 15 _at_ 730 am 1 gt Pilocarpine 1 _at_ 440
pm
Next Day

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Initiation of Diagnostic
Treatment Program

Physical Diagnosis Open-Angle Glaucoma
Category of Glaucomatous Damage
Right Eye Moderate
Left Eye Mild
Initial Target Pressure
Right Eye 20 mmHg
Left Eye 16 mmHg
Initial Treatment Timolol and Pilocarpine

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Case Report 1Coding for 1st Visit (Blue
Cross Ins)

CPT code 92004 126.28 Medical
Eye Examination
CPT code 92135 (RT) 44.50 Retinal
Scanning Laser
CPT code 92135 ( LT) 44.50
Retinal Scanning Laser
CPT code 92083 76.87 Visual
Field Examination
CPT code 92286 138.26
Specular Microscopy
CPT code 92100 86.16
Serial Tonometry
CPT code 76513 (RT) 97.87 High Resolution
Biomicroscopy
CPT code 76513 (LT) 97.87 High Resolution
Biomicroscopy
Total for initial visit 712.31

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Case Report 2

A 62-year old White man returned to the office
for an
eye examination with a chief complaint of blurred
vision.
The History of Present Illness described a
subjective
decrease in vision over the past one month. The
quality
of the blurred vision was described as, like
seeing a film
over my eyes. The blurred vision was present in
both
eyes, moderate in severity, and seemed to be
getting
worse. Other than re-wetting eyedrops for
contact lens
wear, the patient reported using no modifiers for
his
condition. Previous eye exam was 15 months
earlier.

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Patient History Case 2

MEDICATIONS Insulin, Glucophage, Zestril,
Plavix, and Lipitor
PAST MEDICAL HISTORY Diabetes, hypertension,
hyperlipidemia, sleep apnea
PAST OCULAR HISTORY Significant for full-time
soft contact lens wear for 25 years and mild
nonproliferative diabetic retinopathy for 2 years
REVIEW OF SYSTEMS Significant for chronic
numbness of the feet

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Medical Eye Examination Service Components

Acuity w/CLs OD 20/20 OS 20/50
IOP Non-Contact Tonometer _at_ 945 am
OD - 11 OS - 16
Biomicroscopy All structures normal
Ophthalmoscopy
(1) Retinal hemorrhage Left Eye
(2) Exudative maculopathy Left Eye
(3) Peripapillary atrophy Both Eyes

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Medical Eye Examination Clinical Diagnosis

Determining a clinical diagnosis of glaucoma
suspect only leads to other questions.
Question 1 Does the patient have glaucoma?
Question 2 How bad is the macular edema
in the left eye?
Question 3 Is there anything else wrong
with the patient?

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Initiation of Diagnostic Treatment
Program

Determination of Differential Diagnoses
These diseases, which share symptoms or
signs with the clinical diagnosis, must be
identified and excluded
for the diagnostic process to continue.
Differential Diagnosis 1 Glaucoma
Differential Diagnosis 2 Visual Field
Defect
Differential Diagnosis 3 Corneal
Disorder

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Initiation of Diagnostic
Treatment Program

Refraction
O.D. 5.50 0.50 x 090 20/20
O.S. 3.75 0.50 x 090 20/25
Contact Lenses
(1) Proclear Multifocals by Cooper Vision
(2) Modified monovision for past 5 years
(3) Daily wear 1 month discard cycle

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Initiation of Diagnostic Treatment
Program

Fundus Photography
(1) Comparative retinal photographs from
15 months earlier reveal a worsening
of the exudative maculopathy Left Eye
(2) Flame hemorrhage in the left eye is in
the peripapillary region, not on the
optic disc therefore, hemorrhage is
secondary to diabetic retinopathy.

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Initiaton ofDiagnostic Treatment
Program

Visual Field Examination
No clinically significant visual field
defects exist - (poor test reliability)
Scanning Laser Polarimetry
1. Moderate fallout of retinal nerve fiber
layer Both Eyes - (atypical scans)
Specular Endothelial Microscopy
1. Severe corneal dystrophy Both Eyes
2. Reduced cell density Both Eyes

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Initiation of Diagnostic
Treatment Program
Specular Photomicrographs
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Initiation of Diagnostic Treatment
Program