The Slit Lamp Exam – Episode 3, Direct Illumination with Narrow Slit Width — Transcript

Full transcript

1. 0:00welcome to the video series the slit
2. 0:03lamp exam this video explains the use of
3. 0:06direct illumination with narrow slit
4. 0:09width and the slit lamp exam
5. 0:12it covers the following topics
6. 0:14illumination principle usage specific
7. 0:18advantages slit-lamp setup how to apply
8. 0:21the technique and common errors
9. 0:25Uma nation principle direct illumination
10. 0:28with a narrow slit width is a technique
11. 0:30that allows the light to optically
12. 0:32dissect the semi-transparent media of
13. 0:34the eye in this technique the light beam
14. 0:37acts like a knife which cuts through the
15. 0:39different layers of semi-transparent
16. 0:41tissues and allows the examiner to
17. 0:43observe and accurately locate the
18. 0:46structures and alterations
19. 0:50usage it is used in the examination of
20. 0:53semi-transparent structures like the
21. 0:55cornea and the lens where it creates an
22. 0:59optical section however the fine slit
23. 1:02illumination can also be used for
24. 1:04evaluating the height of lumps and bumps
25. 1:06and other structures of the eye such as
26. 1:09the conjunctiva or the iris
27. 1:14specific advantages the main advantage
28. 1:18of the optical section is that it
29. 1:20enables the localization of alterations
30. 1:23which show increased light scattering in
31. 1:25semi-transparent issues this opacity
32. 1:28would appear in its lateral extent when
33. 1:31viewed with a broad illumination however
34. 1:34its depth appears only when narrowing
35. 1:36the beam to a fine slit in this case the
36. 1:39finding is located approximately in the
37. 1:41anterior third of the stroma another
38. 1:44particular advantage of using a fine
39. 1:46slit illumination is that it allows for
40. 1:48the observation of changes in the
41. 1:50profile and the thickness of tissues in
42. 1:52this case for example the slit beam
43. 1:55reveals the thinning of the cornea
44. 1:59or in this case the reflection of the
45. 2:02slit on the iris shows how its contour
46. 2:04is affected by the melanoma
47. 2:07slit-lamp set up to set up the slit lamp
48. 2:10choose a high light intensity
49. 2:14and a very narrow slit with
50. 2:18the illumination angle is selected
51. 2:20according to anatomical conditions
52. 2:22somewhere between 30 and 50 degrees
53. 2:26a magnification of 16 times 225 times is
54. 2:30recommended to localize the depth of
55. 2:32alterations and ten times to 16 times
56. 2:35for assessing the profile of the cornea
57. 2:39how to apply the technique it can be
58. 2:42difficult to focus on a semi-transparent
59. 2:45structure such as the cornea a simple
60. 2:48way of getting the cornea into focus is
61. 2:50as follows
62. 2:51move your slit-lamp towards the patient
63. 2:54until the iris is in focus narrow the
64. 2:58slit and increase the illumination
65. 2:59intensity then increase the illumination
66. 3:02angle and move backwards you can see the
67. 3:06focus on the cornea moving towards the
68. 3:08center the more you move the slit lamp
69. 3:10backwards
70. 3:14increase the magnification if required
71. 3:18using the optical section for the
72. 3:20examination of the lens is relatively
73. 3:22simple when you use the capsular bag as
74. 3:25landmark when you have the cornea and
75. 3:28focus just move the slit-lamp in until
76. 3:31your focus is on the anterior capsule of
77. 3:33the lens you will need to reduce the
78. 3:36illumination angle for reaching the
79. 3:38posterior capsule
80. 3:41for the evaluation of changes in profile
81. 3:44in a given structure
82. 3:47bring the slit-lamp in focus and choose
83. 3:49a large illumination angle the larger
84. 3:52the illumination angle is the better you
85. 3:54see changes in profile
86. 3:58common errors when scanning the cornea
87. 4:01or the lens with a fine slit there is a
88. 4:04significant risk of missing small
89. 4:06alterations in the tissue or on the
90. 4:09surface this is because the field of
91. 4:11view is restricted to the intersection
92. 4:13plane which is very narrow therefore
93. 4:16always scan the cornea with a moderate
94. 4:19slit and a narrow the slit only when
95. 4:21investigating the localization of
96. 4:23findings
97. 4:26thank you for watching The Hulk stride
98. 4:29team wishes you are not a success in
99. 4:31using this illumination technique this
100. 4:34episode was made possible with the
101. 4:36following contributions