Dark Room Procedures for undergraduates(MB,BS) in the field of Ophthalmology are explained in simple terms in this presentation. Series of lectures taken at Central Park Medical College Lahore Pakistan.
2. Dark Room Tests
Dr. Zia-Ul-Mazhry
FCPS(Pak),
FRCS(Edin),
FRCS(Glasgow),
CIC Ophth- (UK)
Assistant Professor
Central Park Medical college Lahore
Consultant Eye Surgeon &
Head of Department
WAPDA Teaching Hospital Complex Lahore.
3. Dark room Tests
• Oblique Illumination
• Distant Direct Ophthalmoscopy
• Direct Ophthalmoscopy
• Retinoscopy
• Indirect Ophthalmoscopy
– Indirect Ophthalmoscope
– Slit Lamp Biomicroscopy
4. Oblique Illumination
• Objective
– Examination of External and
anterior Segment structures
• Instruments
– Illumination Beam
– Magnification Aid/Microscope
• Method
– Illumination beam at 45 degrees
5. Slit Lamp
• The slit-lamp
is a low-
power
microscope
combined
with a high-
intensity light
source that
can be
focused to
shine in a
thin beam.
6. SLE
• Observation by optical
section
• Direct diffuse
illumination
• Indirect illumination
• Retro-illumination
• Scattering sclero-
corneal illumination
• Fundus observation
and gonioscopy with
the slit lamp
7. SLE
• The slit lamp exam uses an
instrument that provides a
magnified, three-dimensional (3-D)
view of the different parts of the eye.
During the exam, your doctor can
look at the front parts of the eye,
including the clear, outer covering
(cornea), the lens, the colored part
(iris), and the front section of the
gel-like fluid (vitreous gel) that fills
the large space in the middle of
the eye.
• Special lenses can be placed
between the slit lamp and the
cornea (or directly on the cornea) to
view deeper structures of the eye,
such as the optic nerve, retina, and
the area where fluid drains out of
the eye (drainage angle ). A camera
may be attached to the slit lamp to
8. Distant Direct
Ophthalmoscopy
• Objective
– To Examine and classify media
opacities against fundal glow
• Instrumentation
– Direct Ophthalmoscope
• Methods
– Throw the light with DO at half
meter distance
– Parallax Method of deviation
9. Distant Direct
Ophthalmoscopy
• Parallax Method of deviation
– Ask the patient to move his/her
eye
– Opacities Moving
• With
– Anterior to nodal point
• No movement
– At or very near to nodal point
• Against Movement
– Behind the nodal point
10. Distant Direct
Ophthalmoscopy
• Viewing ocular
media
– Observe red reflex
– Look for media
opacities
• Cataracts
• Corneal scars
• Large floaters
13. Examination Technique
• dim the lights.
• ask the
patient to
fixate on a
distant target.
• approach the
patient from
the side.
• examine the
optic nerve
and
surrounding
retina.
16. Direct Ophthalmoscopy:
Basic skills
• Proper position for
central fundus
viewing
• Right eye to right
eye
• Left eye to left eye
• Don’t rub noses…
23. Direct Ophthalmoscopy
• Advantages
– Portable
– Easy to use
– Upright image
– Magnification 15x
– Can use w/o dilation
• Disadvantages
– Small field of view
– Lack of stereopsis
– Media opacities can
degrade image
24. Indirect Ophthalmoscopy
• Monocular or binocular
• Advantages:
– Wide field of view
– Binocular instruments
provide stereopsis
• Disadvantages:
– Requires more skill
– Decreased magnification
(3x)
– Requires dilation
– Inverted image
36. Macula
• Lies about 2DD (disc
diameters) temporal to the
optic disc
• Should be avascular
• May appear darker red than
surrounding retina
• Should see bright foveal reflex
on younger pts
37. The Indirect Ophthalmoscope
George T. Timberlake, Ph.D.
Department of Ophthalmology
University of Kansas Medical Center
Gullstrand Indirect
Ophthalmoscope
ca. 1910
38. Allvar Gullstrand
1862 - 1930
Professor of Physical &
Physiological Optics,
University of Uppsala
First “reflex free”
ophthamoscope
Nobel Prize 1911 for
work on optics of eye
Swedish Ophthalmologist
GTT 04
39. Gullstrand Principle
for Reflex-free Ophthalmoscopy
Light entrance and exit separated in pupil plane
Light entering eye
Light leaving eye Pupil
GTT 04
40. Retinoscopy
• Objective
– To determine refractve status of
the eye
• Instrumentation
– Retinoscope
– Trial Lens set
– Trial frame
41. Retinoscopy
• Methods
– Ask the patient to fixate on a
distant target
– Half to 1 meter distance
– Project the streak on pupil
– Move the streak and observe the
movement of red reflex
42. Retinoscopy
• Moves with
– Emetropia
– Hyperopia
– Myopia of less than 1 diopter
• No Movement
– Myopia of exactly 1 diaopter
• Moves against
– Myopia of more than 1 diopter
43. Retinoscopy
• Insert +1 D Lens in front of the
eye while working at 1 meter
– No movement
• Emetropia
– With movement
• Hyperopia
– Against movement
• Myopia of < 1 D