sl exam pt i

April 7, 2023April 7, 2023 Slit Lamp Examination - ICSlit Lamp Examination - IC 11

INSTRUCTION COURSEINSTRUCTION COURSE

SLIT LAMP EXAMINATIONSLIT LAMP EXAMINATION

MP STATE OPHTHALMIC MP STATE OPHTHALMIC CONFERENCECONFERENCEUJJAINUJJAIN20082008


Presented byPresented by

Dr. Sanjay ShrivastavaDr. Sanjay ShrivastavaDr. Nikhilesh Trivedi Dr. Nikhilesh Trivedi Dr. Kavita Kumar Dr. Kavita Kumar


Slit Lamp Examination Slit Lamp Examination

The science of examination with a slit lamp is called Biomicroscopy as it allows in vivo study of living tissues at high magnification.


SLITLAMP EXAMINATIONSLITLAMP EXAMINATION

• Permits detailed examination of various structures of and posterior segment of eye

• Angle of anterior chamber with gonioscope • Measurement of intra ocular pressure • Endothelial cell counts


SLITLAMP EXAMINATIONSLITLAMP EXAMINATION

• Photographic representation of every above mentioned part of the eye

• Modern slit lamp and its auxiliary devices provide magnified view of parts of eye from cornea to retina

• Measurement of Corneal thickness is also possible


• Slit lamp is a misnomerSlit lamp is a misnomer• In 1925 MAVAS introduced a term bio- In 1925 MAVAS introduced a term bio-

microscopy defined as examination of the microscopy defined as examination of the living eye by means of the corneal microscope living eye by means of the corneal microscope and slit lamp.and slit lamp.

• LITTMAN in1950 introduced the rotatory LITTMAN in1950 introduced the rotatory magnification charger based on the principle magnification charger based on the principle of GALILEAN telescope is the forerunner of of GALILEAN telescope is the forerunner of current ZEISS slit lamp . current ZEISS slit lamp .


PARTSPARTS

A. OBSERVTION SYSTEMA. OBSERVTION SYSTEMB. ILLUMINATION SYSTEMB. ILLUMINATION SYSTEMC. MECHANICAL SYSTEMC. MECHANICAL SYSTEM


Slit lampSlit lamp


The InstrumentThe Instrument


The The InstrumentInstrument


Posterior Segment Posterior Segment Examination with +78 D LensExamination with +78 D Lens


OBSERVATION SYSTEMOBSERVATION SYSTEM

a. Objective lenses -22 a. Objective lenses -22 dioptersdiopters

b. Eye piece- 10 dioptersb. Eye piece- 10 diopters


ILLUMINATION SYSTEMILLUMINATION SYSTEM

a. Light source a. Light source b. Condenser lens systemb. Condenser lens systemc. Slit and other diaphgramc. Slit and other diaphgramd. Filtersd. Filterse. Projection lense. Projection lensf. Reflecting mirror/prism2. f. Reflecting mirror/prism2.


MECHANICAL SYSTEMMECHANICAL SYSTEM

A. Joy stick arrangementA. Joy stick arrangementB. Up and down arrangement B. Up and down arrangement C. Patient support arrangementC. Patient support arrangementD. Mechanical couplingD. Mechanical coupling


Slit Lamp Examination -MethodSlit Lamp Examination -Method

• Prerequisites – Preferably a dark room and slit lamp biomicroscope

• Position – Patient is seated comfortably on an adjustable stool, with chin resting against chin rest and forehead against head rest bar.


PREPARATIONPREPARATION

A. Preliminary examination of eye ballA. Preliminary examination of eye ballB. Illumination of room.B. Illumination of room.C. Preparation and management of C. Preparation and management of

patients patients D. Adjustment of instruments.D. Adjustment of instruments.E. StereopsisE. Stereopsis


METHODS OF ILLUMINATIONMETHODS OF ILLUMINATION

• Diffuse illuminationDiffuse illumination• Sclerotic scatterSclerotic scatter• Direct focal illuminationDirect focal illumination• Indirect illuminationIndirect illumination• Retro-illuminationRetro-illumination• Specular reflection Specular reflection


SET UPSET UP

1. Angle between microscope and 1. Angle between microscope and illuminating system – 30 deg to illuminating system – 30 deg to 45 45 deg. deg. 2. Slit width - widest.2. Slit width - widest.3. Filters - diffusing filter3. Filters - diffusing filter4. Magnification - low to medium 4. Magnification - low to medium 5. Illumination – low to high. 5. Illumination – low to high.


USEUSE

1. Topography of pathological changes.1. Topography of pathological changes.2. Entire surface of cornea, iris, lens can 2. Entire surface of cornea, iris, lens can

be viewed.be viewed.3. Folds of descemets membrane.3. Folds of descemets membrane.4. Corneal scar.4. Corneal scar.5. Whole configuration of lens.5. Whole configuration of lens.6. Surface of adult nucleus.6. Surface of adult nucleus.


SCLEROTICSCLEROTIC SCATTERSCATTERAlso called indirect lateral illumination-it is possible by concentrating the beam upon the spot at the side of the object it is proposed to examineProjecting the light upon sclera near the limbus,it is easy to examine the limbal portion of cornea,and if the incident ray is sufficient to induce total internal reflection,the whole of cornea including the opposite limbus ,is lit up.


USEUSE

1. Corneal opacities1. Corneal opacities2. Keratocele2. Keratocele3. Interstitial deposits3. Interstitial deposits4. Perforating scars4. Perforating scars


DIRECTDIRECT FOCAL ILLUMINATIONFOCAL ILLUMINATIONBASIS OF ALL METHODS.BASIS OF ALL METHODS.


SET UPSET UP

Slit beam is regulated until it Slit beam is regulated until it coincides with exact focus of coincides with exact focus of microscope. microscope.

Light - narrow slit at an oblique Light - narrow slit at an oblique angle 30 deg to 45 degangle 30 deg to 45 deg


THREE SLIT BEAM THREE SLIT BEAM EFFECTSEFFECTS

• OPTICAL SECTIONOPTICAL SECTION• PARALLELOPIPED CORNEAL PARALLELOPIPED CORNEAL

SECTION SECTION• CONICAL BEAM EFFECTCONICAL BEAM EFFECT


I. OPTICAL SECTIONI. OPTICAL SECTION• Produced by a very narrow slit beam Produced by a very narrow slit beam

focused obliquely.focused obliquely.• It resemble a knife like histological section It resemble a knife like histological section

of tissue focused.of tissue focused.Corneal section uses Corneal section uses

• changes in corneal curvature.changes in corneal curvature.• change in corneal thickness.change in corneal thickness.• depth of corneal pathologies; foreign body depth of corneal pathologies; foreign body

localization.localization.


OPTICAL SECTIONOPTICAL SECTION

Corneal optic section showing;Tear layer-anterior most bright zoneEpithelial layer-dark line immediately behind it.Bowmen’s membrane-a bright line.Stroma-wider granular and greyer zone.Descemets membrane and endothelial layers-posterior most bright zone.


II. PARELLOPIPED CORNEAII. PARELLOPIPED CORNEA 2-3 mm. wide focused slit 2-3 mm. wide focused slit

beam.beam. Because beam traverse Because beam traverse

cornea obliquely, shape of cornea obliquely, shape of resulting rectangular block is resulting rectangular block is paralellopiped prism. the paralellopiped prism. the ext. and internal surface of ext. and internal surface of which slightly curved owing which slightly curved owing to anatomic shape of corneato anatomic shape of cornea


USESUSES

1. Pathologies of epithelium and Stroma.2. Corneal scar or infiltrates. Appear brighter.3. Water clefts have low density so appear black.


III. CONICAL BEAMIII. CONICAL BEAM

Small circular beam Used to detect the aqueous flare


INDIRECT ILLUMINATIONINDIRECT ILLUMINATION

Slit beam is focused at a point just behind a area to be examined.


SET UPSET UP

Angle between slit beam and Angle between slit beam and microscope is 30 deg to 45 degmicroscope is 30 deg to 45 deg

- Beam width - moderate - Beam width - moderate

- Illumination - low medium or high - Illumination - low medium or high


USESUSES

• Corneal infiltration Corneal infiltration • Corneal microcystsCorneal microcysts• Corneal vacuoles Corneal vacuoles • Epithelial cells Epithelial cells


RETROILLUMINATIONRETROILLUMINATION Examination of Examination of

normal or normal or pathological pathological structures in structures in light reflected light reflected from tissue from tissue situated more situated more posteriorly posteriorly


RETROILLUMINATIONRETROILLUMINATION


Direct retro illuminationDirect retro illumination

Observer in direct pathway of lightObserver in direct pathway of light

Light is reflected from structures Light is reflected from structures so pathology seen against so pathology seen against illuminated backgroundilluminated background


Indirect retro illuminationIndirect retro illumination

Observer is right angle to observed Observer is right angle to observed structures not in line so pathology structures not in line so pathology seen against dark non illuminated seen against dark non illuminated backgroundbackground


Pathologies can be Pathologies can be

1. Obstructive – seen as dark against light 1. Obstructive – seen as dark against light background eg pigment or blood filled background eg pigment or blood filled vesselsvessels

2. Respersive –these scatter light but not 2. Respersive –these scatter light but not obstruct completely seen as bright obstruct completely seen as bright against dark background eg epithelial against dark background eg epithelial edema, precipitates.edema, precipitates.


Pathologies can be Pathologies can be

3. Refractile – they distort the view of 3. Refractile – they distort the view of junction of illuminated and dark area junction of illuminated and dark area because there refractive index is because there refractive index is different from surroundings eg different from surroundings eg Vacuoles.Vacuoles.


SPECULAR REFLECTIONSPECULAR REFLECTION

• It is one of the most difficult methods. Not It is one of the most difficult methods. Not possible to use on all kind of slit lampspossible to use on all kind of slit lamps

• Reflection of light occurs when beam of Reflection of light occurs when beam of light is incident on an optical surface called light is incident on an optical surface called zone of discontinuity, such zones may be zone of discontinuity, such zones may be found in cornea and lens found in cornea and lens

• When observer is placed in pathway of When observer is placed in pathway of reflected light a dazzling reflex seen called reflected light a dazzling reflex seen called specular reflection specular reflection


SET UPSET UP

• Illuminating and viewing arms each forms and Illuminating and viewing arms each forms and angle of about 30 deg to the central angle of about 30 deg to the central perpendicular perpendicular

• Slit beam height of 2 mm and focused onto Slit beam height of 2 mm and focused onto the central corneal endothelium the central corneal endothelium

• Golden sheen with darker lines outline the Golden sheen with darker lines outline the hexagonal endothelial cells hexagonal endothelial cells

• Magnification of atleast 40X is needs to see Magnification of atleast 40X is needs to see endothelial pattern endothelial pattern


USESUSES

• Surface pathologies scatter the light Surface pathologies scatter the light irregularly. therefore create dark area in irregularly. therefore create dark area in reflex.reflex.

• Using an eye piece reticule endothelial Using an eye piece reticule endothelial cells can be measured and counted cells can be measured and counted and also used to study the tear film and also used to study the tear film details . details .


Oscillating illumination of KoppeOscillating illumination of Koppe

• Slit beam is given an oscillatory Slit beam is given an oscillatory movement by which it is often movement by which it is often possible to see minute objects and possible to see minute objects and filaments especially in the filaments especially in the aqueous which would otherwise aqueous which would otherwise escapes detection escapes detection


SPECIALISED USES SPECIALISED USES

1. Gonioscopy 1. Gonioscopy 2. Fundus examination with focal 2. Fundus examination with focal illumination illumination 3. Pachymatery3. Pachymatery4. Applanation tonometry 4. Applanation tonometry 5. Ophthalmodynamometry5. Ophthalmodynamometry


SPECIALISED USESSPECIALISED USES 6. Slit lamp photography 6. Slit lamp photography 7. As a delivery system for argon , 7. As a delivery system for argon ,

diode and Nd YAG laser diode and Nd YAG laser 8. Laser interferometry8. Laser interferometry9. Potential acuity meter test9. Potential acuity meter test


END OF PART ONEEND OF PART ONETHANKSTHANKS

sl exam pt i

Health & Medicine

slit lamp

descemets

corneal scar

corneal thickness

slit beam

dark

pathologies

lens