The document discusses the slit lamp's function as a standard method for examining the eye's anterior segment, detailing its historical development and optical systems. It describes various techniques, illumination methods, and filters used in slit lamp examinations, as well as the components that contribute to its effectiveness for diagnosing ocular conditions. The document emphasizes the importance of proper patient and observer adjustments in conducting thorough eye examinations.

1. SLIT LAMP
PRESENTOR – DR. ANNIRUDH GUPTA
MORDERATOR- DR. VINEETA PAI
23- FEBRUARY 2024

2. INTRODUCTION
• Routine method of of examining the outer and
anterior segment of the eye.
• Consist of – low powered binocular compound
microscope linked to an adjustable bright light
source.
• Isolation of the layers or entity to be viewed is the
key to slit lamp biomicroscopy.
OPTICS OF COMPOUND MICROSCOPE.

3. HISTORY
• 1806- HIMLY used a simple convex lens (to create
focal illumination).
• 1823- PURKINJE used magnifying glasses (to
increase magnification).
• 1897- CZAPSKI: binocular stereoscopic microscope.
• 1911- GULLSTRAND designed the first slit lamp by
focusing the filament of the light bulb on the slit
aperture to create more focal illumination on
cornea.
SCHANZ-CZAPSKI INSTRUMENT FOR
STEREOSCOPIC EYE EXAMINATION.

4. HISTORY
• 1916- KOEPPE and HENKER –combined Gullstard’s
slit lamp on and articulated arm with stereoscopic
microscope both mounted on same stand
• 1920- VOGT- altered the optics: filament of light
focused on condensing lens rather than on cornea
which resulted in more homogenous bright light on
cornea.
1916- KOEPPE AND HENKER
SLIT LAMP

5. HISTORY
• 1933- GOLDMAN- introduced 3 control element for
cross-slide stage and combine swivel axis foe
microscope and illumination system in HAGG-
STREIT slit lamp.
• 1950- LITTMAN AND ZERISS- combined joystick
control (Goldman), illumination path and also
added stereo-telescope system with magnification
changer.
1950- LITTMAN AND ZERISS
SLIT LAMP

6. Placeholder Title 08
HAGG-STREIT SLIT LAMP
LIGHT FROM ABOVE
ZEISS SLIT LAMP
LIGHT FROM BELOW
TYPES- ON BASIS OF ILLUMINATION

7. HAGGSTREIT
ABBRIVATIONS MEANING
B BULB
CL CONDENSING LENSES
OL OBJECTIVE LENS
M MIRROR

8. ZEISS
ABBRIVATIONS MEANING
B BULB
CL CONDENSING LENSES
OL OBJECTIVE LENS
M MIRROR

9. OPTICS OFSLITLAMP
• 2 Basicsystem-
• Illumination system
• Microscope system
• Alignmentissuchthatthepointonwhichmicroscopeis
focusedcorrespondstothepointonwhichlightis
focused.
• Thisisachievedbythemicroscopeandthelightning
systemhavingacommonfocalplane.
• Theircommonaxisofrotationalsoliesinthisfocalplane.

10. KOHLER’S PRINCIPLE OF ILLUMINATION.
• Light source is transmitted to objective lens by the collector system
and through slit aperture.
• Provides homogenous slit image even with a structured light source
PARTS OF SLIT LAMP.
• BASIC DESIGN-
• OBSERVATION SYSTEM
• ILLUMINATION SYSTEM
• MECHANICAL SUPPORT SYSTEM.

11. OBSERVATION SYSTEM
• Essentially a compound microscope with 2 optical
elements-
• Objective lens +22d
• Eye piece +10d
• Prism
• Provide lage working distance in front of
microscope for manupulation on patient eye
• Back vertex distance is 90-120 mm
• Lable it

12. MICROSCOPE SYSTEM
• Eyepiece system uses astronomical telescope
system
• Gallelian telescope system- sits between
objective and eyepiece lens, provides large
range of magnification
• Total magnification = magnification of ( objective
lens + telescope + magnification changer)

13. Placeholder Title 06
ASTRONOMICAL TELESCOPE GALLELIAN TELESCOPE

14. DIFFERENCE BETWEEN GALLELIAN AND ASTRONIMICAL TELESCOPE
PROPERTY GALLELIAN ASTRONOMICAL
Fo Convex (+ve) Convex (+ve)
Fi Concave (-ve) Convex (+ve)
TUBE LENGTH SHORT (Fo-Fi) long (Fo + Fi)
MAGNIFICATION Upto 4x Upto 10x
IMAGE Virtual and erect Real and inverted
FIELD SIZE Smaller Larger

15. Placeholder Title 03
ILLUMINATION
SYSTEM

16. FILTERS IN SLIT LAMP
• Diffuse- general overall observation of eye and adenexa.
• Cobalt blue- enhances view of fluorescein dye in tear film. Typically used
for fluorescein staining and gat.
• Red free filter- enhances view of blood vessels and hemorrhages.
• Neutral density- decrease maximum brightness for photosensitive
patients.
• Yellow filter- good for contrast enhancement.

17. MECHANICAL
SUPPORT SYSTEM

18. Placeholder Title 0
SLIT
LAMP
PARTS

19. TECHNIQUES OF EXAMINATION AND PRE-REQUISITES.
• Patient Adjustment- Chin Rest, Forehead Bar, Lateral Canthus
Alignment, Fixation Target.
• Observer Adjustment- Height Of Table, Eyepiece, I.P.D.
• Pre-requisite- Semi Dark Room, Start With Low Magnification

20. CHRONOLOGY OF EXAMINATION
1. LIDS AND LASHESH
2. CONJUNCTIVA
3. CORNEA AND TEAR FILM
4. AQUOUS HUMOUR
5. IRIS
6. LENS
7. ANTERIOR VITEROUS

21. METHOD OF ILLUMINATION.
1. DIRECT-
1. DIRECT DIFFUSE
2. DIRECT FOCAL
3. SPECULAR
4. TANGENTIAL
2. INDIRECT-
1. INDIRECT PROXIMAL
2. RETRO-ILLUMINATION
3. SCLEROTIC SCATTER

22. DIRECTDIFFUSE
• Facilitates simultaneous observation of large
areas at low magnification
• Initiating slit lamp examination in this manner
generates an early overall impression
Magnification Low (6-10x)
Diffuse illumination Medium intensity
Width Maximum
Angle 15 degrees

23. APPLICATION OF DIRECT DIFFUSE
• Gross general examination of anterior
segment of eye and adnexa.
• Provide useful introduction to overall
condition.
• RGP contrast lens fitting.
• Corneal epithelium staining for defects
and T.B.U.T. Using cobalt blue filter.

24. DIRECTFOCAL
Magnification 10x – 40x
Illumination Medium – high intensity
Width Narrow-Broad
Angle 45- 60 degrees
• Both slit beams and microscopes are focused at
same point
• Slit beam, angle and illumination can be varied
and one can move from a general view of
anterior segment to a 3-D optic section of
cornea, AC or lens

25. DIRECT FOCAL
• Dense opacities blocks light and casts shadow through stroma on to iris
and decemets membrane.
• Translucent refractive index (same at stroma), absorbs and reflects some
light
• Refractive index less than stroma, diverging cone of light in stroma
• Refractive index greater than stroma, converging cone of light in stroma
• Image

26. DFI:PARELLELEPIPED
• Beam width 2-3mm
• Provides layered view of cornea and lens
• Application:
• Depth and extent of corneal abrasion, scarring and
foreign body
• Corneal nerves
• Endothelial pigmentation
• Pathologies of corneal epithelium and stroma

27. DFI:OPTICALSECTION
• Width 0.2 – 0.3mm
• Height: full
• Magnification and illumination: medium to high
• Facilitates cross-sectional view of cornea and lens
• Optical section decreases scattering of light
• Maximises contrast between illumination section and
dark, unilluminated background
• Greater angular presentation, increase distance
between anterior and posterior surface of the structure
under study

28. APPLICATION
• Change in corneal curvature and thickness
• Depth of pathologies
• Anterior chamber angle grading (van herick’s grading)
• Lens: zone of discontinuity and lens opacities can be seen
• Image

29. Van Herick’s Grading
• Method of evaluation and AC angle
• The beam of light is used to estimate the ratio of corneal thickness to the
most peripheral part of the AC
• The light beam is projected at 1mm from the limbus at a 60 degree angle
from temporal side
• Image grade Ac depth/corneal thickness Remark
4 ≥ 1 Wide angle
3 ¼ - ½ Open angle
2 ¼ Narrow angle (gonio)
1 < ¼ Gonioscopy shows narrow
angle

30. DFI:CONICALBEAM
• SMALL CIRCULAR BEAM- PINPOINT OR PENCIL OF LIGHT
• SIZE = 1X3MM
• MAGNIFICATION AND ILLUMINATION = HIGH
• BEAM IS FOCUSED BETWEEN CORNEA AND ANTERIOR
LENS SURFACE.
• DARK ZONE BETWEEN CORNEA AND LENS IS OBSERVED
• PRINCIPLE = TYNDALL EFFECT.
• APPLICATION= DETECTION AND GRADING OF AQUOUS
FLARE AND CELLS.

31. STANDERDIZED UVIETIS NOMENCLATURE (S.U.N)
GRADING
GRADE FLARE CELLS PER FIELD
0 ABSENT 0
1+ FAINT, BARELY DETECTABLE 5-10
2+ MODERATE, IRIS & LENS DETAILS
CLEAR
10-20
3+ MARKED, IRIS AND LENS DETAILS
HAZY.
20-50
4+ INTENSE FLARE, FIBRINOUS
AQUOUS.
>50
• GRADING IS DONE AT 16X MAGNIFICATION
• BEAM SIZE OD 1X2MM
• IMAGE

32. SPECULARREFLECTION
• Normal light reflex bouncing off a surface.
• Smooth surface of cornea: plain mirror
• SUBJECT TO SNELL’S LAW <I = >r
• Patients’s gaze is directed to bisect the angle
between the axis of illumination and that of the
microscope. (45-60 degree).
• Monocular procedure.

33. SPECULAR REFLECTION
• WITH BEAM AT CENTER OF CORNEA, OBSERVER
SEES 3 LIGHTS-
• SLIT BEAM PARALLELEPIPED IN CORNEA.
• BEAM REFLECTED FROM IRIS NASAL TO
PARELLELEPIPED
• 1ST
PURKINJE IMAGE ‘CORNEAL LIGHT REFLEX’
TEMPORAL TO PARALLELEPIPED. • IMAGE
ANGLE 45-60 DEGREE
MAGNIFICATION MEDIUM TO HIGH
ILLUMINATION HIGH
SLIT H=3MM W=0.5MM

34. SPECULAR REFLECTION
• IMAGE
ANTERIOR POSTERIOR
INCREASE INTENSITY BECAUSE OF HIGHT
DIFFERENCE BETWEEN REFRACTIVE
INDEX OF AIR AND TEAR FILM
DECREASE INTENSITY BECAUSE OF
LESSER DIFFERENCE BETWEEN
REFRACTIVE INDEX OF ENDOTHELIUM
AND AQUOUS.

35. APPLICATION OF SPECULAR REFLECTION
• Endothelial Cell Density And Morphology
• Tear Film Evaluation.
• Evaluation Of D.M. Of Cornea.
• Guttae And KPs Appear As Non Reflective
Dark Areas
• IMAGE

36. BROAD TANGENTIAL
ILLUMINATION
• Wide Beam Oriented At Extremely Oblique
Illumination Angle 70-90 Degree
• Enhances Surface Irregularities By Creating
More Shadows, Used To Observe Surface
Texture.
• Greater Angle- Light Reflected And Scattered By
Cornea Decrease- Thus Reduced Glare.

37. BROAD TANGENTIAL ILLUMINATION
• APPLICATIONS
• ANTERIOR CORNEAL SURFACE IRREGULARITIES.
• POSTERIOR CORNEAL SURFACE AND DM FOLDS.
• IEIS AND ANTERIOR LENS SURFACE EXAMINATION.
• IMAGE
ANGLE 70-90 DEGREE
MAGNIFICATION LOW TO HIGH
ILLUMINATION LOW TO MEDIUM
SLIT WIDE
HEIGHT- NARROW

38. INDIRECTILLUMINATION
• Slit Beam Is Directed Adjacent To The Area Of
Interest To Illuminate It Indirectly.
• Beam Directed To Adjacent Area- Total Internal
Reflection Within Cornea- Light Spreads
Through Stroma-light Striking Opacity Scattered
And Some Reflected Back To Observer.

39. INDIRECT ILLUMINATION
• Applications
• Define An Opaque Area In Cornea And Identify
Details Within The Opacity.
• Location And Determinantion Of Size And Shape
Of Embedded Fb.
• Corneal Microcytes And Vacuoles.
• Observing Iris Sphincter. • IMAGE
ANGLE 30-45 DEGREE
MAGNIFICATION LOW TO HIGH
ILLUMINATION LOW TO MEDIUM
SLIT 2-3 MM WIDE

40. RETROILLUMINATION FROMIRIS
• METHOD OF EXAMINING A PARTICULAR PART
OF EYE BY LIGHT REFLECTED FROM A
STRUCTURE BEHIND IT.
• USED TO STUDY OPTICAL QUALITIES OF LESION.
ANGLE 15-30 DEGREE
MAGNIFICATION 16X – 25X
ILLUMINATION MODERATE
SLIT 3-3 MM WIDE
REDUCED HEIGHT

45. RETROILLUMINATION FROM
FUNDUS
• LIGHT ENTERS DILATED PUPIL- REFLECTED BACK
FROM RPE AND CHOROID- EMERGES FROM
PUPIL- RED REFLEX
ANGLE COAXIAL
MAGNIFICATION 16X – 25X
ILLUMINATION MODERATE TO HIGH
SLIT MODERATE WIDTH

46. APPLICATION OF RETRO ILLUMINATION
• EXAMINATION OF ANTERIOR VITEROUS, LENS
AND CORNEA.
• DENS SCAR AND OPACITIES (DARK AGAINST
RED BACKGROUND)
• TRANSPARENT AND TRANSLUCENT OBJECTS:
BRIGHT REFRACTIVE.
• EARLY KERATOCONUS: OIL DROP REFLEX
• CATARACT FORMATION AND SUBLUXATION
OF LENS.
• FINGERPRINT DYSTROPHY.
• IMAGE

47. SCLEROTICSCATTER
• TECHNIQUE FOR ILLUMINATING CORNEA
• PRINCIPLE: TOTAL INTERNAL REFLECTION.
• BEAM DIRECTED AT SCLERAL LIMBUS- ENTIRE
CORNEA ILLUMINATED
ANGLE 15 DEGREE
MAGNIFICATION LOW TO MEDIUM
ILLUMINATION HIGH
SLIT MEDIUM WIDTH
FULL HEIGHT.

48. APPLICATION OF SCLEROTIC SCATTER
• CORNEAL FOREIGN BODY.
• CORNEAL OPACITIES.
• SUBEPITHELIAL INFILTRATES.
• CORNEAL VERTICILLIA.

49. SEQUENCE OF SLIT LAMP EXAMINATION OF CORNEA
SEQUENCE AND TYPE OF ILLUMINATION TYPE OF INFORMATION ABOUT CORNEA
DIFFUSE GENERAL SURVEY AND LOCATION OF ABNORMALITY
SCLEROTIC SCATTER PATTERN OF ABNORMALITY
FOCAL SLIT DEPTH OF OPACITY
BROAD TANGENTIAL SURFACE DETAILS
PROXIMAL INTERNAL DETAILS
RETRO ILLUMINATION FROM IRIS OPTICAL QUALITIES
RETRO ILLUMINATION FROM FUNDUS OPTICAL QUALITIES
SPECULAR REFLECTION SURFACE IRREGULARITY, ENDOTHELIAL MOSAIC
COLOUR FILTERS GREEN ENHANCE VESSELS AND PIGMENTS
BLUE: ENHANCE FLUORESCENCE.

50. ACCESSORY DEVICES
• APPLANATION TONOMETRY
• GONIOSCOPY
• FUNDUS EXAMINATION
• PACHYMETRY
• SLIT LAMP PHOTOGRAPHY AND VIDEOGRAPHY
• LASER DELIVERY SYSTEM
• POTENTIAL ACUTY METER TEST