The slit lamp examination is a crucial tool for detailed and magnified examination of the eye's tissues, enabling various techniques such as tonometry and ophthalmic photography. It comprises a viewing arm, an illumination arm, and a patient positioning frame, and offers multiple illumination methods for assessing different ocular tissues. This procedure is essential for diagnosing conditions and planning treatments related to the eye, particularly for evaluating the anterior segment and assessing intraocular pressure.

1. SLIT LAMP EXAMINATION

2. • Is a unique instrument that permits magnified
examination of transparent and translucent tissues of
the eye in cross- section.
• It enhances the external examination by allowing a
binocular, stereoscopic view with a wide
magnification ×10-×500
• Permits applanation tonometry to measure IOPs and
examination of posterior segment

3. Uses of slit lamp
• Provides detailed examination of virtually all tissues of the eye
and its adnexia
• Routinely used for examination of the anterior segment,
vitreous and structures anterior to it.
• Optical constraints of the instrument and eye to be examined
prevent useful visualization of the angle of the AC and other
structures posterior to A/ viterous.
• Used in tonometry
• Linear measurement of tissues or lesions
• Ophthalmic photography
• Contact lens fitting

4. Parts of a slit lamp

5. • The slit lamp has three principal portion:
• Viewing arm containing eye piece and magnifying
elements
• Illumination arm: light source and many of controls
• Patients position frame

6. • 1 eye piece
• 2 viewing arms
• 3 instrument magnification elements
• 4 a lever for adjusting magnification
• 5 illumination arm
• 6 illumination lamp
• 7 calibrated scale
• 8 lever adjusting brightness of the light beam;
different light ;blue, green, red light

7. • 9 a projecting knurled knob
• 10 knob facing examiner
• 11 Knurled dual knobs for changing the width of the beam light
• 12 patients positioning frame
• 13 two upright metal rods to which are attached the forehead
strap
• 14 patients chin rest
• 15 a pad of disposable paper are attached
• 16 fixation light
• 17 Joy stick

8. Illumination
Magnification
Joystick assembly
Pt- rest assembly

9. Magnification
Eye piece
Objective piece

10. Forehead strap
Chin Rest

11. Joy stick assembly

12. Stand

13. Preparing and positioning a patient
• The patient’s head is positioned and steadied for the
examination by means of a chin rest and forehead
strap
• Chin rest has a concave plastic cup to which is
attached a stack of disposable tissue papers
• The height of the patient is lowered or raised by
means of a nearby knob
• The patient’s eye is brought level with the black
demarcation line, one of the support’s rods.

14. cont
• The patient’s chin should be well seated in the chin rest
• The forehead pressed firmly against the forehead strap
• Patient may drift backwards and so they need help
• The viewing and illumination parts should be in good
condition
• It can be difficult to position the slit lamp and its head
rest close to obese patients; their upper body tend to
push everything away

15. cont
• Patients who are relatively short can be supported by
sitting on a pillow
• Children are examined either by standing or kneeling
on the chair
• Ask the patient if they are comfortable before you
start examination

17. Height

18. Distance

20. Principles of slit lamp
special properties
• Direct illumination
• Direct focal illumination
• Specular reflection
• Trans illumination or retro illumination
• Indirect lateral illumination
• Sclerotic scatter

21. Diffuse illumination
• Is used mainly in obtaining an overview of ocular
tissues e.g. conjunctiva
• Can be used to examine intraocular tissues like iris,
and lens capsule
• May be used by red light cobalt light
• With white light use full height broad beam directed
on the surface of the eye.
• The brightness can be lowered since the broad beam
will be uncomfortable for the patient.

22. cont
• The cobalt blue produces green yellow color with
fluorescein
• This is used to evaluate ulcers discern fluorescein
pattern during Goldman Applanation

23. Direct focal illumination
• Is achieved by directing a full height, medium width,
medium bright beam obliquely into the eye, focusing on
the cornea a quadrilateral block of light illuminates the
cornea
• The anterior surface of the paralleled piped represents
the anterior surface of the cornea
• The posterior surface represents the posterior surface of
the cornea
• The same can be applied to focus on the crystalline lens
• When the light is shortened its used to grade flare and

24. • Cell in the anterior chamber.

25. Specular reflection
• Also reflected illumination
• Used to examine corneal endothelium
• May also be used to focus the lens and corneal surface
• When reflected on the cornea the examiner can identify
single cells of endothelium
• Medium to narrow beam is applied to examined the
surface of the eye
• A bright zone of this reflection will be evident on the
temporal and mid periphery of corneal epithelium

26. Transillumination
• Also known as retroillumination, backlights tissues to
be examined
• Allows to examine vacuoles edema in the corneal
endothelium, blood vessels in the cornea, atrophy of
the iris and other abnormalities on the cornea
• Transillumination of the fundus is well appreciated in
a dilated pupil.

27. Indirect lateral illumination
• The light is directed just to the side of the lesion to
be examined
• Some of the light enters the lesion causing it to glow
internally
• Most useful for translucent lesion like corneal opacity
or iris nodules

28. Scleratic scatter
• Is usefull in detecting subtle corneal opacities
• The less transparent areas become highlighted as they
scatter the internally reflected light
• It requires making the illumination arm not parfocal with the
viewing arm
• Is directed on the limbus by rotating the illuminating arm
temporary while the examiner views the center of the
cornea.
• The light from the limbus traverses the cornea by alternately
reflecting off the anterior and posterior corneal surface

29. Goldman tonometry
• Tonometry is the objective measurement of
intraocular pressure , based most commonly on the
force required to flatten the cornea or the degree of
corneal indentation produced by a fixed force

33. Technique
• The patient is positioned at the slit-lamp with the
forehead firmly against the headrest.
• Topical aneasthesia and fluorescein are instlled into
the conjunctival sac
• With the cobalt blue filter and the brightest beam
projected obliquely at the prism, the prism is centred
in front of the apex of the cornea
• The dial is preset between 1 and two
• The prism is advanced until it just touches the apex

34. • Of the cornea
• Viewing is switched to the ocular of the slit-lamp
• A pattern of two semi-circles will be seen one above
and one below the horizontal midline which represent
the fluorescein stained tear film touching the upper
and lower outer halves of the prism
• The dial on the tonometer is rotated to align the inner
margins of the semicircles just touching
• The reading on the dial multiplied by ten=IOPs

36. Potential errors
• Inappropriate fluorescein pattern- resulting from
excessive fluorescein
• Pressure on the globe- patient squeezing the eye
• Corneal edema
• Corneal thickness- thin cornea lead to
underestimation
• Incorrect caliberation

37. Reducing risk of infection
• Avoid tonometry in individuals with overt infection
• Using a disposable sleeves which covers the tip of
tonometer
• Swabbing the tip of tonometer thoroughly with
alcohol prep pads
• Wiping and the soaking the tonometer in 3% solution
of hydrogen peroxide

38. Schiozt tonometer

39. procedure

40. Gonioscopy
• This involves the examination and analysis of
the angle
• Diagnostic- facilitates the identification of
abnormal angle structures and estimation of
the width of the chamber angle
• Surgical- involves visualization of the angle
during procedures like goniotomy

41. Technique
• The preliminary steps are the same as for fundus
examination
• The angle is visualized with the small dome shaped
gonioscopic mirror
• Initially the mirror is placed at 12o’clock to visualize
the inferior angle
• When the view of the angle is obscured by a convex
iris, it is possible to see over the hill by asking the
patient to look in the direction of the mirror.

42. • When the plane of the iris is flat the patient should be
asked to look away from the mirror in order to obtain
a view parallel to the iris with optimal image quality

43. Identification of angle structures
• Schwalbe line
• The corneal wedge
• Trabeculum meshwork
• Schlemm canal
• Scleral spur
• The ciliary body
• Iris process
• Blood vessels

46. Grading
• Grade 4 (35-45⁰) is the widest angle characteristic of
myopia in which the ciliary body can be visualized
with ease, it is capable of closure
• Grade 3(25-35⁰) is an open angle in which at least the
scleral spur can be identified, it is also incapable of
closure
• Grade 2(20 ) is a moderate narrow angle in which
⁰
only trabeculum can be identified; angle closure is
possible but unlikely

47.  Grade 1(10 ) is very narrow angle in which only
⁰
schwalbe line, and probably the top of trabeculum
can be identified
 Slit angle is one there is no obvious iridocorneal
contact but no angle contact but no angle structures
can be identified. The angle has greatest danger of
eminent closure
 Grade 0 is closed due to iridocorneal contact

48. Gonioscopy

49. Goniolenses
Goldmann
• Single or triple mirror
Zeiss
• Contact surface diameter 12 mm
• Coupling substance required
• Four mirror
• Coupling substance not required
• Contact surface diameter 9 mm
• Suitable for ALT
• Not suitable for indentation gonioscopy
• Suitable for indentation gonioscopy
• Not suitable for ALT

50. Tonometers
Goldmann
Contact applanation
Perkins
Portable contact applanation
Pulsair 2000 (Keeler)
Air-puff
Schiotz
Portable non-contact applanation
Non-contact indentation
Contact indentation
Tono-Pen
portable contact applanation