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SLIT-LAMP BIOMICROSCOPY Module 1.4
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Published in Australia by The International Association of Contact Lens Educators
First Edition 1997 The International Association of Contact Lens Educators 1996
All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, without the prior
permission, in writing, of: The International Association of Contact Lens Educators
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Email: iacle@iacle.org
CONTRIBUTORS
Slit-lamp Biomicroscopy Procedures:
Sylvie Sulaiman, BOptom, Mcom
Deborah Sweeney, BOptom, PhD
THE SLIT-LAMP BIOMICROSCOPE
PARTS OF A SLIT-LAMP
1. Mechanical support
2. Observation system
3. Illumination system
EXAMINING A PATIENT USING A SLIT-LAMP
SLIT-LAMP MICROSCOPE SYSTEM
Variable magnification
Binocular system
FEATURES
SLIT-LAMP MICROSCOPE
SLIT-LAMP MICROSCOPE
Low 7X - 10X General eye
Medium 20X - 25X Structure layers
High 30X - 40X Detail
General eye: Lids Bulbar conjunctiva/sclera Cornea/limbus Tears Anterior chamber/iris/crystalline lens
LOW MAGNIFICATION (7x - 10x) SLIT-LAMP BIOMICROSCOPY
SLIT-LAMP BIOMICROSCOPY
SLIT-LAMP BIOMICROSCOPY
Structures:
Epithelium Stroma Endothelium Lens fit/surface
MEDIUM MAGNIFICATION (20x - 25x)
SLIT-LAMP BIOMICROSCOPY
SLIT-LAMP BIOMICROSCOPY
Details:
Epithelial changes
Stromal striae, folds
Endothelial folds, polymegethism
HIGH MAGNIFICATION (30x - 40x)
SLIT-LAMP BIOMICROSCOPY
SLIT-LAMP BIOMICROSCOPY
Epithelium
Vacuoles
Microcysts
Dystrophies
HIGH MAGNIFICATION (30x - 40x)
SLIT-LAMP BIOMICROSCOPY
SLIT-LAMP BIOMICROSCOPY
Stroma
Striae
Folds
HIGH MAGNIFICATION (30x - 40x)
SLIT-LAMP BIOMICROSCOPY
SLIT-LAMP BIOMICROSCOPY
Endothelium Polymegethism Guttata Blebs Dystrophies Cell Density
HIGH MAGNIFICATION (30x - 40x)
SLIT-LAMP BIOMICROSCOPY SPECULAR REFLECTION: ENDOTHELIUM
STRUCTURES OBSERVED WITH
DIFFERENT ILLUMINATIONS
SLIT-LAMP BIOMICROSCOPY
Method of illumination is IMPORTANT
SLIT-LAMP ILLUMINATION SYSTEM
Variable light intensity Filters Width Height Angle
FEATURES
SLIT-LAMP ILLUMINATION SYSTEM
ILLUMINATION TECHNIQUES
Diffuse
Direct
Indirect
Retro-illumination
Specular reflection
Sclerotic scatter
Tangential
ILLUMINATION TECHNIQUES
DIFFUSE ILLUMINATION
45 degree angle between light & microscope
Slit open fully Diffusing filter Variable magnification (low to high)
BROAD BEAM
Microscope Beam of light
Cornea
Iris
DIFFUSE ILLUMINATION
Overall view of: Lids and lashes Conjunctiva Cornea Sclera Iris Pupil
DIRECT ILLUMINATION
Observation and illumination systems focused on the same point
DIRECT ILLUMINATION
Microscope
Beam of light
Iris
Cornea
DIRECT ILLUMINATION
Vary angle of illumination
Low to high magnification
Vary width and height of light source
DIRECT ILLUMINATION
Optic Section narrow, focused light
Parallelepiped wider, focused light
Conical Beam small, circular light
DIRECT ILLUMINATION OPTIC SECTION
Indicates depth localize: - nerve fibres
- blood vessels - infiltrates - cataracts
Anterior chamber angle
PRINCIPLE OF OPTIC SECTION
Aerial View
Cornea
Iris
B
A
OPTIC SECTION
A B
DIRECT ILLUMINATION
Broader view
Illuminated block of the cornea
More extensive examination
PARALLELEPIPED
PRINCIPLE OF THE PARALLELEPIPED
Iris
Cornea
Aerial View
A A'
B B'
PARALLELEPIPED
A A'
B B'
DIRECT ILLUMINATION
Inflammatory cells/flare in the anterior chamber
Darkened room
CONICAL BEAM
CONICAL BEAM
Microscope Conical beam
Cornea
Iris
Conical Beam
Beam cross-section
INDIRECT ILLUMINATION
Observation and illumination systems are not focused at the same point
INDIRECT ILLUMINATION
Microscope
Beam of light
Cornea
Iris
INDIRECT ILLUMINATION
Vary angle of illumination
Slit beam is offset
Vary beam width
Low to high magnification
INDIRECT ILLUMINATION
Valuable for observing:
Epithelial vesicles Epithelial erosions Iris pathology Iris sphincter
RETRO-ILLUMINATION
Object of regard is illuminated only by reflected light
RETRO-ILLUMINATION
Microscope
Beam of light
Iris
Cornea
RETRO-ILLUMINATION
Vary angle of illumination Moderately wide beam Slit beam is offset Medium to high magnification Reflected light from iris or fundus
Observer
Transparent intra-corneal object
Background for marginal retro-illumination
Unreserved (U) and reversed (R) appearance
DIVERGING REFRACTOR
CONVERGING REFRACTOR (AFTER Brown, 1971)
U R
RETRO-ILLUMINATION
Direct Direct and full view
Indirect Adjacent
Marginal Margin or edge
TYPE ALIGNMENT
Alignment of reflected beam with area under observation
RETRO-ILLUMINATION
Valuable for observing: Vascularization Epithelial oedema Microcysts Vacuoles Dystrophies Crystalline lens opacities Contact lens deposits
SPECULAR REFLECTION
Angle of incidence equals angle of reflection
SPECULAR REFLECTION
Microscope Beam of light
Cornea
Iris
SPECULAR REFLECTION
Valuable for observing:
Endothelial cell layer
Tear film debris
Tear film lipid layer thickness
SCLEROTIC SCATTER
Valuable for observing:
localised epithelial oedema (CCC)
corneal scars
foreign bodies in the cornea
SCLEROTIC SCATTER
Corneal feature disclosed
SCLEROTIC SCATTER
TANGENTIAL ILLUMINATION
Large angle of 70o - 80o between
illumination and observation system
TANGENTIAL ILLUMINATION
Microscope
Beam of light Cornea
Iris
TANGENTIAL ILLUMINATION
Valuable for observing:
Iris freckles
Tumours
General integrity of cornea and iris
FILTERED ILLUMINATION
Cobalt blue
Green (red-free)
Neutral density
FILTERED ILLUMINATION
Most valuable:
Cobalt blue
+ Wratten # 12
FILTERED ILLUMINATION
Valuable for observing:
Tear layer
Ocular staining
RGP lens fitting patterns
GRATICULE
Useful for lens fitting assessment
ROUTINE EXAMINATION OF
THE EYE USING THE
SLIT-LAMP
BASELINE EXAM FLOWCHART
Lids Conjunctiva
Limbus Cornea
Tears Anterior Chamber
Iris Lens
Bulbar Palpebral
SLIT-LAMP OBSERVATIONS OF CONTACT LENS COMPLICATIONS
LID EXAMINATION
Lids redness, swelling, defects, growths,
discolouration
Puncta clear, functioning
Caruncle swollen, inflamed
CONJUNCTIVA
Redness Inflammation
LIMBUS
Redness
Neovascularization
Staining
CORNEA
Transparency
Tissue damage/insult
DETECTION OF OEDEMA
Corneal clarity
Striae/folds
Corneal thickness measurement
STRIAE
Refractile effect
Fluid separation of collagen fibrils
Minimum 5% corneal swelling
Refit with higher Dk/t lenses
CORNEAL OEDEMA vs STRIAE
0 5 10 15 20 25
25
20
15
10
5
0
Striae (number)
striae = 1.45 x oedema - 6.5 n = 192 r = 0.88 p < 0.001
(La Hood & Grant, 1990)
Oedema (%)
FOLDS
Physical buckling of Descemet's membrane and the endothelium
Minimum 8% corneal swelling
Severely compromised cornea
Immediate refit with higher Dk/t
FOLDS
CORNEAL OEDEMA vs STRIAE
1 Striae = 5.2% Oedema Each
= 1% Oedema additional striae
CORNEAL OEDEMA vs STRAIE
1 Fold = 7.7% Oedema Each
= 1% Oedema additional striae
CORNEAL OEDEMA vs FOLDS
0 5 10 15 20 25
25
20
15
10
5
0
Folds (number)
folds = 1.33 x oedema - 9 n = 166 r = 0.87 p < 0.001
(La Hood & Grant, 1990)
Oedema (%)
DAYTIME STRIAE RESPONSE
0 0 0
0.6
0.1
1.0
0.3
1.1
0
0.5
1
1.5
0 2 4 6
High WaterLow Water
HIGH WATER 74% vs LOW WATER 43%
Striae (Grade 0-4) (La Hood, 1991)
+5.00 D n=11
Time after lens insertion (hours)
MICROCYSTS
Small, irregular shape (15-50 m) Reversed illumination Slow onset Cyclic phenomenon Asymptomatic
MICROCYSTS DISPOSABLE HFDROGELS
0 4 8 12 16 20 24 28 32 36
50
40
30
20
10
0
Microcysts (number)
(Grant et al., 1990)
Time (months)
6-13N
DW
MICROCYSTS
Basal epithelial cells secrete intra-epithelial sheets
Disorganised cell growth Pockets of dead cells Slowly pushed to surface
PATHOLOGY
MICROCYSTS ONSET AND RECOVERY
35
30
20
10
0
Microcysts (number)
0 2 4 6 8 10 12 0 2 4 6 Time (months)
HWC n=51 CCLRU
HWC n=29 GOTEBORG
MICROCYSTS
. . . Break through the anterior
corneal surface and manifest as
corneal dry spots
(Zantos, 1981)
ENDOTHELIUM
Detection with slit-lamp:
High magnification (30x - 40x)
High illumination
Specular reflection
POLYMEGETHISM SIGNS
Increasing variation in endothelial cell size
Increased ratio of large/small cells
CCLRU POLYMEGETHISM SCALE GRADE
1 2 3 4
CLINICAL SIGNIFICANCE OF POLYMEGETHISM
POLYMEGETHISM
Age
Diseases (diabetes, etc)
Trauma
Contact lenses
CAUSES
TEAR EXAMINATION
Quality
Lipid layer
Debris
TEAR EXAMINATION
Quality BUT (fluorescein)
Tear prism height
Movement of debris
Rose Bengal staining
ANTERIOR CHAMBER
Transparency
Cells and flare
Persistent pupillary membrane
IRIS EXAMINATION
Architecture Inflammation Pigmentation Naevi Iridectomy Colobomas
CRYSTALLINE LENS EXAMINATION
Orange Peel Opacities Pigment on capsule Centration Iris attachments
THANK YOU
Table of Contents
14
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SYMBOLS
ABBREVIATIONS
ACRONYMS
ACRONYMS