Method of illumination direct o character of aperture

Method of illumination:
Direct
o Character of aperture: Wide
open
o Typical magnification: 5-45x
o Angle of illumination: ~60
o
-
90
o
o Filter: Neutral density
VAN HERRICK TECHNIQUE
For examination of depth of anterior chamber (useful for diagnosis
of glaucomatous processes)
Qualitative Evaluation of Angle of Anterior Chamber
 TECHNIQUE
o Method of illumination: Direct
o Character of aperture: Narrow beam (close to
limbus)
o Typical magnification: Medium
o Angle of illumination: ~60
o
o Filter: Neutral density
‐
In slit lamp, view ant to post
-Examine 3 regions (L, mid, R)
-Point of reference:thickness of slit
light
-Thickness on L and R side should be
the thickness of the anterior chamber
(if same =1x)
-Middle (dapat malalim, this is the
Corneal thickness = 3-4x)
FUNDOSCOPY WITH SLIT LAMP
3 ‐ MIRROR GONIOSCOPIC LENS
o TECHNIQUE
 Character of aperture: Moderate slit beam
 Typical magnification: 16-45x
 Angle of illumination: Coaxial (~10
o
)
 Filter: Neutral density
4 mirrors: 1
st
: used to view angle; 2
nd
: view surface of iris; 3
rd
: view
posterior of iris; 4
th
: central mirror, view the retina
CONTACT SLIT LAMP FUNDOSCOPY LENSE SLIT LAMP

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OPHTHALMOLOGY
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Transcribers: PAGGAO | YALA Page 9 of 9
o TECHNIQUE
 Character of aperture: 2mm
 Typical magnification: 16-45x
 Angle of illumination: Coaxial (5-10o)
 Filter: Neutral density
NON ‐ CONTACT SLIT LAMP FUNDOSCOPY LENSES
o TECHNIQUE
 Character of aperture:
Moderate (2mm)
 Typical magnification:
16-45x
 Angle of illumination:
Coaxial (~10
o
)
 Filter: Neutral density

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OPHTHALMOLOGY
_________________________________________________________________________________________________________________________________________________________________
Transcribers: BUGAYONG | GELOSO Page 1 of 3
1.02C OBJECTIVE & SUBJECTIVE EXAMINATION OF THE EYE ‐
VISUAL ACUITY
DR. MONDIGUING ‐ August 18, 2017
PRELIMS: QUIZ 1
Bold,red letters = Emphasized during lecture
Italic, blue letters = Audio
Green= OT
VISUAL ACUITY
 first examination done in eye assessment
 most frequently done
 recorded as “VA”
 is a FRACTION:
Test dstance
Distance at which the smallest optotype
identified subtends an angle of 5 minutes of an arc
OPTOTYPES
 Optoptype refers to letters, numbers or images that are seen
in a visual acuity chart
 Size of letters are all measure and scaled so when you
measured them they are all 5 minutes of an arc
 Minute refers to measurement of an angle, smaller than a
degree
 1 minute = .0166 degree (you don’t need to memorize these)
Basis for Constructing the Optotype
- optotype that is at 20/200 means at 200 ft this is the size
of a letter that subtends an angle of 5 degrees of an arc.
- The letter only becomes bigger as the distance becomes
farther. So if the patient is at 50 ft, the letter should be that
big (refer to image) and at 100ft, it should be that big. The
size of the optotype changes depending on the distance of
the observer.
VISUAL ACUITY: MEASUREMENT
 Normal visual acuity is 20/20
 SNELLEN’S CHART – most commonly used, level of difficulty
is different per row
 BAILEY – LOVIE CHART - level of difficulty is equal per row
 Measured in 2 ways:
o Distance Vision
o Near Vision
We usually do distance vision first then near vision
DISTANCE VISION
 Measured at a certain distance: 20ft or 6m with ample