The document discusses slit lamp examination, which allows detailed examination of eye structures using high magnification. It describes the three main components of a slit lamp: the observation system including lenses and eyepiece, illumination system including light source and filters, and mechanical system for adjusting positioning. Various illumination techniques are outlined including diffuse, direct focal, indirect, retro-illumination and specular reflection. Specific uses and methods for examining different eye structures are provided. Specialized uses of slit lamps for procedures like gonioscopy and laser treatment are also mentioned.

1. INSTRUCTION COURSE SLIT LAMP EXAMINATION MP STATE OPHTHALMIC CONFERENCE UJJAIN 2008

2. Presented by Dr. Sanjay Shrivastava Dr. Nikhilesh Trivedi Dr. Kavita Kumar

3. 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.

4. SLITLAMP 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

5. SLITLAMP 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

6. Slit lamp is a misnomer In 1925 MAVAS introduced a term bio- microscopy defined as examination of the living eye by means of the corneal microscope and slit lamp. LITTMAN in1950 introduced the rotatory magnification charger based on the principle of GALILEAN telescope is the forerunner of current ZEISS slit lamp .

8. PARTS A. OBSERVTION SYSTEM B. ILLUMINATION SYSTEM C. MECHANICAL SYSTEM

9. Slit lamp

10. The Instrument

11. The Instrument

20. Posterior Segment Examination with +78 D Lens

21. OBSERVATION SYSTEM a. Objective lenses -22 diopters b. Eye piece- 10 diopters

22. ILLUMINATION SYSTEM a. Light source b. Condenser lens system c. Slit and other diaphgram d. Filters e. Projection lens f. Reflecting mirror/prism2.

23. MECHANICAL SYSTEM A. Joy stick arrangement B. Up and down arrangement C. Patient support arrangement D. Mechanical coupling

24. Slit 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.

25. PREPARATION A. Preliminary examination of eye ball B. Illumination of room. C. Preparation and management of patients D. Adjustment of instruments. E. Stereopsis

26. METHODS OF ILLUMINATION Diffuse illumination Sclerotic scatter Direct focal illumination Indirect illumination Retro-illumination Specular reflection

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

28. USE 1. Topography of pathological changes. 2. Entire surface of cornea, iris, lens can be viewed. 3. Folds of descemets membrane. 4. Corneal scar. 5. Whole configuration of lens. 6. Surface of adult nucleus.

29. SCLEROTIC SCATTER Also called indirect lateral illumination-it is possible by concentrating the beam upon the spot at the side of the object it is proposed to examine Projecting 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.

30. USE 1. Corneal opacities 2. Keratocele 3. Interstitial deposits 4. Perforating scars

31. DIRECT FOCAL ILLUMINATION BASIS OF ALL METHODS.

32. SET UP Slit beam is regulated until it coincides with exact focus of microscope. Light - narrow slit at an oblique angle 30 deg to 45 deg

33. THREE SLIT BEAM EFFECTS OPTICAL SECTION PARALLELOPIPED CORNEAL SECTION CONICAL BEAM EFFECT

34. I. OPTICAL SECTION Produced by a very narrow slit beam focused obliquely. It resemble a knife like histological section of tissue focused. Corneal section uses changes in corneal curvature. change in corneal thickness. depth of corneal pathologies; foreign body localization.

35. OPTICAL SECTION Corneal optic section showing; Tear layer-anterior most bright zone Epithelial 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.

36. II. PARELLOPIPED CORNEA 2-3 mm. wide focused slit beam. Because beam traverse cornea obliquely, shape of resulting rectangular block is paralellopiped prism. the ext. and internal surface of which slightly curved owing to anatomic shape of cornea

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

38. III. CONICAL BEAM Small circular beam Used to detect the aqueous flare

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

40. SET UP Angle between slit beam and microscope is 30 deg to 45 deg - Beam width - moderate - Illumination - low medium or high

41. USES Corneal infiltration Corneal microcysts Corneal vacuoles Epithelial cells

42. RETROILLUMINATION Examination of normal or pathological structures in light reflected from tissue situated more posteriorly

43. RETROILLUMINATION

44. Direct retro illumination Observer in direct pathway of light Light is reflected from structures so pathology seen against illuminated background

45. Indirect retro illumination Observer is right angle to observed structures not in line so pathology seen against dark non illuminated background

46. Pathologies can be 1. Obstructive – seen as dark against light background eg pigment or blood filled vessels 2. Respersive –these scatter light but not obstruct completely seen as bright against dark background eg epithelial edema, precipitates.

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

48. SPECULAR REFLECTION It is one of the most difficult methods. Not possible to use on all kind of slit lamps Reflection of light occurs when beam of light is incident on an optical surface called zone of discontinuity, such zones may be found in cornea and lens When observer is placed in pathway of reflected light a dazzling reflex seen called specular reflection

49. SET UP Illuminating and viewing arms each forms and angle of about 30 deg to the central perpendicular Slit beam height of 2 mm and focused onto the central corneal endothelium Golden sheen with darker lines outline the hexagonal endothelial cells Magnification of atleast 40X is needs to see endothelial pattern

50. USES Surface pathologies scatter the light irregularly. therefore create dark area in reflex. Using an eye piece reticule endothelial cells can be measured and counted and also used to study the tear film details .

51. Oscillating illumination of Koppe Slit beam is given an oscillatory movement by which it is often possible to see minute objects and filaments especially in the aqueous which would otherwise escapes detection

52. SPECIALISED USES 1. Gonioscopy 2. Fundus examination with focal illumination 3. Pachymatery 4. Applanation tonometry 5. Ophthalmodynamometry

53. SPECIALISED USES 6. Slit lamp photography 7. As a delivery system for argon , diode and Nd YAG laser 8. Laser interferometry 9. Potential acuity meter test

54. END OF PART ONE THANKS