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Binocular Indirect Ophthalmoscopy

Binocular Indirect Ophthalmoscopy is known to provide a wider view of the inside of the eye. It is one of the most commonly used ophthalmic instrument.

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Binocular Indirect Ophthalmoscopy

  1. 1. Dr.Shah-Noor Hassan FCPS,FRCS Assistant Professor Vitreo-Retina BSMMU
  2. 2. History of ophthalmoscope  Mery in 1704 made first ophthalmoscopic observation of a normal fundus in a drowning cat  Cumming and Brucke in 1846 explained the principles of ophthalmoscopy 2
  3. 3.  THREE basic principles described by Hermann von Helmholtz  Patient and observer should be made emmetropic  Retina of the patient should be sufficiently illuminated  Optical alignment of light source and observer’s pupil 3
  4. 4. • Ruete in 1852 designed first monocular indirect ophthalmoscope 4
  5. 5.  Marc-Antoine Giraud- Teulon of France (1861)  Weak source of illumination. 5
  6. 6. • 1911-Thorner and Allvor Gullstrand – Reflex free ophthalmoscopy • 1946 – Charles Schepens- modern binocular indirect ophthalmoscope 6
  7. 7.  The illuminating and viewing beams must be totally separated through the cornea, pupillary aperture, and lens (to avoid reflections) but must coincide on the retina to permit viewing 7
  8. 8. Direct Indirect Monocular view Binocular view Limited field of view (10-15 degrees) Wide field of view (35 degrees) Poor view in hazy media Better view in hazy media One has to go very close to the patient Working distance is about 35-40 cms Drawing of retinal lesions is difficult & incomplete Drawing of retinal lesions are easier Difficult to use during surgery Can be used for fundus examination during surgery Illumination: 0.5 – 2 Watts Illumination: 15 – 18 Watts 15 times magnification 2-5 times magnification Virtual and erect image Real and inverted image 8
  9. 9. Instrument:  Magnifying eyepiece  Relay system re-inverts image to a real one  Image is focused using eye piece Indication of use:  Small pupils  Uncooperative children  Patients intolerant to bright illumination 9
  10. 10.  Headpiece illumination condensing oculars  Convex lenses in the eyepieces of +2.00 D to relax the accommodation and view aerial image  Condensing hand held lens ( +30D; +20D; +14D)  Scleral depressors 10
  12. 12. • Three types • Biconvex • Plano convex • Aspheric • Two different curved surfaces - to avoid spherical aberration • Steeper curvature faces the examiner • + 20 ,+30 , +14 D 12
  13. 13. Dioptric power 30 D 20 D 14 D Magnification Field Stereopsis Focal Length 2 60o ½ normal 3.3 cm 3 37o ¾ normal 5 cm 4 30o 1 normal 7 cm 13
  14. 14.  For viewing the fundus periphery and oral region  Suggested by Trantas in 1900- used nail  Thimble depressor – Schepens  Articulated scleral depressor  Hand held scleral depressor 14
  15. 15. 15
  16. 16.  To make the eye highly myopic by placing a strong convex lens in front of patients eye  The emergent rays forms a real inverted image between the lens and observer’s eye 16
  17. 17. 17
  18. 18.  Binocularity is achieved by artificially reducing the observer’s IPD to approximately 15mm by the help of prisms/mirrors 18
  19. 19.  More in myopia and less in hypermetropia as compared to emmetropia 19
  21. 21.  Emmetropic eye, rays from fundus are parallel, brought to a focus by the condensing lens  Image formed at the principal focus of the lens  Hence, size of image remains the same, no matter the position of lens. 21
  22. 22.  Rays are convergent  Image formed in front of the eye  Final image by condensing lens within its own focal length  Image is smaller when lens is nearer to anterior focus of the eye and larger when away 22
  23. 23.  Rays divergent and appear to come from behind the retina  Image by condensing lens in front of its principle focus  Image is larger when lens is nearer to the anterior focus of the eye and smaller when away. 23
  24. 24.  In Emmetropia: - at the principal focus  In Myopia: - Nearer to the lens than its principal focus  In Hypermetropia: - Farther away from the principal focus 24
  25. 25.  Patient's pupil size  Power of the condensing lens  Over all size of the condensing lens  Refractive error (very small amount )  Distance the condensing lens is held from the patient's eye 25
  26. 26.  Real, inverted and magnified  Magnification depends on: -  Dioptric power of the convex lens  Position of lens in relation to the eyeball  Refractive state of the eyeball 26
  27. 27. • Explain the procedure • At least one attendant in examination room • Make the patient feel comfortable • Dilate pupils • Darken the room • Keep both eyes open 27
  28. 28.  Adjust head band  Eye pieces are as close to the pupil as possible (+2.0D in eye piece to compensate for the accommodation)  Eye pieces should be perpendicular to pupillary axis 28
  29. 29. Adjust IPD Face a wall approximately 40 cms away, and adjust the illumination mirror such that the illumination field is vertically centralized to the observation ports
  30. 30.  Sitting position a. First b. Opacities may move out of the way in one position c. Change in retinal folds and expose retinal breaks which may not be otherwise visible  Lying down position a. Easier for the patient b. Examination of periphery 30
  31. 31.  Hold the condensing lens with non-dominant hand  Dominant hand for multiple functions which requires dexterity like: -  Keeping patients eyelids apart when necessary  Using scleral depressor  Adjusting the knobs of the ophthalmoscope  AND MOST IMPORTANT SKETCHING FUNDUS DETAILS 31
  32. 32. • Condensing lens grasped between bulb of thumb & tip of flexed index finger • Middle finger holds one lid & thumb of other hand, the other lid • Flex the wrist • Most lenses are coded either with a white or silver ring, this side is placed toward the patient's eye 32
  33. 33.  Start with minimum intensity  Brief examination in sitting position from disc to equator  Then patient lies down for detailed fundus examination and fundus charting 33
  34. 34.  Both eyes of the patient should be open  Throw light into the patient’s eye from an arm’s distance and observe for red reflex  Interpose the condensing lens, with more convex side towards the examiner in the path of the beam of light, keeping a watch on the reflex close to the patient’s eye  Slowly move the lens away from the eye till the image of the retina is clearly seen  This is usually at the focal length of the lens 34
  35. 35.  Move around the head of the patient to examine different quadrant  Stand opposite the clock hour to be examined  Ask the patient to look in extreme gaze to see the more periphery of the fundus  Correct position of the eye: -  Provide a target like patient’s thumb  Non seeing eye: - proprioceptive impulses 35
  36. 36.  Maintain a common line of sight by imagining that the fundus under examination, the centre of the patient’s pupil, the centre of the condensing lens and the examiners visual axis are all connected by an imaginary line. 36
  37. 37.  Shape of pupil and retro-illumination changes with change in gaze  With this changes the amount and extent of peripheral retina seen 37
  38. 38.  Stereopsis is good when the images of the observer’s both pupil are far apart in the patient’s pupil  During examination of fundus periphery, the patient’s pupil appears elliptic to the observer  The observer’s view becomes monocular 39
  39. 39.  While viewing fundus periphery much of the light is imaged outside the patient’s pupil  The light source should be adjusted to bring the image of the light source inside the elliptic pupil 40
  40. 40.  Using variable pupil function and altering the covergence angle of right and left image steropsis can be achived. 41
  41. 41.  Eye is rotated in the direction of the quadrant to be examined  Stand 180° away from the quadrant to be examined  Observer should align his head with the long axis of the pupil. This will allow wider exit pupil for stereoscopic view  Use scleral indenter 42
  42. 42. Change the patients gaze in 20 - 30° increments Observe all the parts of Retina (‘Sweeping of the fundus’) 43
  43. 43.  Examination of both eyes at the same time  For quick comparison of both peripheral fundi pigmentation and appearance 44
  44. 44. • Tilt the BIO lens to remove undesirable reflections • Adjust the illumination slightly higher or lower than center • Moving closer towards the image will magnify the view but decrease the field • Moving away from the image will increase the field of view but decrease the magnification 45
  45. 45. 46
  46. 46.  Adjunct to see the peripheral/anterior parts of the fundus  Dynamic examination (Rolling of lesion)  Usually worn in middle finger of dominant hand  Better control by holding between thumb and index finger 47
  47. 47. Differentiate between a retinal tear and hemorrhage Hemorrhage will become elevated with indentation, holes will either gape open, look larger and/or appear darker with a surrounding edematous (white) cuff. 48
  48. 48.  Place the tip of indenter on the skin on eyelid tarsal plate over the area of sclera to be indented  While examining upper fundus  Close the eyelids  Apply depressor tip to the upper lid at the upper edge of the tarsus  Ask the patient to open the eyelids and look up  Depressor slides easily under the orbital margins 49
  49. 49.  For 3 or 9 o’clock: -  Sometimes necessary to apply pressure over the bulbar conjunctiva directly  Topical anaesthesia  Depressor should be introduced and removed from the conjunctival sac very slowly  Perform this examination last as proparacaine may cause corneal epithelial oedema  Use a 70% isopropyl alcohol swab to clean the depressor 50
  50. 50.  Use indenter tangentially to the globe, with gentle pressure  If used perpendicularly, causes pain and squeezing of eyelids 51
  51. 51.  Axis of the indenter along the meridian of the globe- This ensures tip more likely to be in proper meridian  If introduced obliquely- tip may not be in the observed meridian 52
  52. 52.  Shine your BIO in the pupil and observe the red-orange reflex  Have the patient look in the direction where you have placed the depressor. Apply a light amount of pressure with the depressor. If the depressor is properly aligned along the correct axis, a darkening or change in the quality of the red- orange reflex is seen  Insert the condensing lens and adjust the illumination such that the light shines into the eye in the direction of the depressor 53
  53. 53. • Again apply a light amount of pressure with the depressor. Pay attention to the lower part of the condensing lens • The examiner should see an elevated possibly "grayish mound" of the indented retina. So called “Mouse under the Blanket” phenomena • Indicates that the indenter is in correct position 54
  54. 54.  Indentation beyond the Tarsal Plate  Ora Serrata is 7mm from Limbus. Indenting too anteriorly is useless counter productive If mound of fundus not seen on indentation, its in another location 55
  55. 55.  Don’t apply too much pressure  Be careful in patients who have IOL specifically AC IOL or Iris Supported IOL  Procedure may be painful in patients with high IOP 56
  56. 56. Scleral indentation Retinal breaks in detached retina without indentation Enhanced visualization of breaks with indentation
  57. 57. Recent or suspected penetrating injuries Orbital injuries Intraocular surgery within 8 weeks Correct indentation is not believed to enlarge retinal holes or cause RD 58
  58. 58. 59
  59. 59.  Best Chart Papers are the ones  Avoids Glare  Photographic reproducibility better  Clipped on rigid board which rests on patient’s chest  Oriented upside down so that 12 o’ clock on the chart is towards patients feet 60
  60. 60. Fundus drawing • Place chart upside down • Draw what you see Technique
  61. 61. 3 Concentric Circle Innermost – Equator Middle – Ora Serrata Outermost – Pars plana Radial lines to describe the location of fundus finding in clock hours Posterior pole – in the 1st circle 62
  62. 62. Ora serrata on chart has a larger circumference than the equator, while actually the equator has a greater circumference Centre of the chart: Optic nerve [O] Fovea [+] 63
  63. 63. 64
  64. 64. 65
  65. 65. • Ora – Dentate processes • Ampulla of vortex veins (red Octopus) – approximately at equator 1,5,7,11 o’clock • Long post. ciliary vessels & nerves – 3 & 9 o’clock • Dividing line between anterior and posterior portions of the fundus : Equator 66
  66. 66. 67
  67. 67. • Calculations in mm : 1 DD = 1.5 mm • Elevation: +3DD = 4.5 mm • Distance between each clock hour in the eye • Ora serrata : 3 DD • Equator : 6 DD • Total distance from the • Equator to Ora serrata : 4 DD (6 mm) • Equator to Macula : 6 DD (9 mm) 68
  68. 68. • Enter patient details • Chart placed with the 12-00 meridian facing patient’s feet at 6-00 meridian facing patient’s chin • Stand on the same side as the eye being examined • Stand 1800 from the site to be observed • First observe: Disc, Macula and Post. pole • Trace the major blood vessels as far anteriorly as possible 69
  69. 69.  Whatever meridian we see, its as if we are standing at the ora at that meridian and looking at the post. Pole  Examine a meridian standing 180 degrees away  Constantly check orientation by removing the condensing lens to verify the position of the eye  Draw exactly what is seen  Repeat the examination using scleral indentation  Look for fundus landmarks  Start drawing from disc towards periphery 70
  70. 70.  Direct Ophthalmoscopy easy to learn than indirect  Inversion of image with indirect method of ophthalmoscopy- requires some practice to overcome  INSTRUMENT DIPLOPIA in learners who accommodate on inverted image and necessarily converge as well causing homonymous diplopia  Less magnification  Patient is more uncomfortable with intense bright light 71
  71. 71.  Feared if Indirect Ophthalmoscope used at full intensity for prolonged time  In experimental animals it is seen that damage to outer segment of the photoreceptors and RPE cells does take place  Heat is an important element in this damage  Damage to macula occurs when light thrown more than 7 min 72
  72. 72.  In clinical conditions: -  Light is seldom focused - same area for more than 30-60 seconds  Patient’s slight but constant eye movements  These factors protect against accumulation of heat  Avoid examining macula for prolonged period with full intensity of indirect light  Caution is to be exercised while examining patient’s with high fever since difference of 2° or 3 ° C may sensitize the RPE and retina to photo-damage 73
  73. 73. Filters Green light – Nerve fibre layer, Blood vessels, microaneurysms Red light – Subtle pigmentary abnormalities Blue light – Angioscopy Yellow filter – Reduces photophobia
  74. 74. (1) Clean the lens using contact lens cleaner and warm tepid water, NOT HOT WATER. Then dry with a soft lint free cloth or paper towel. (2) Never autoclave or boil a condensing lens. (3) Place the lens completely in (1) 3% hydrogen peroxide solution (2) 2% Glutaraldehyde aqueous solution 20-25 mins (3) Sodium Hypochlorite 1:10 parts 10 mins (4) Pure 70% Isopropyl Alcohol for 5-10 minutes. 75
  75. 75. INDIRECT OPHTHALMOSCOPY  Binocular view  Use of condensing lens captures peripheral rays  Wide field of view 25° or more depending on lens
  76. 76. INDIRECT OPHTHALMOSCOPY  Check correct interpupillary distance  Beam in centre of viewing frame  Lens flat surface facing the patient  Patient asked to move eyes and head into optimal positions for examination
  77. 77. NORMAL FUNDUS  Pink optic disc with cup in centre  Arteries lighter in colour and narrower than veins  Red background due to choroidal vessels and retinal pigment epithelium  Central macula
  78. 78. The Indirect Ophthalmoscope Gullstrand Indirect Ophthalmoscope ca. 1910 George T. Timberlake, Ph.D. Department of Ophthalmology University of Kansas Medical Center
  79. 79. If the retina could light up…. Emmetropic eye Image of retina on distant surface GTT 04 Fundamental Principle of the Indirect Ophthalmoscope
  80. 80. Ophthalmoscopic lens Aerial image of retina Fundamental Principle of Indirect Ophthalmoscope GTT 04
  81. 81. Viewing the aerial image with a magnifier GTT 04
  82. 82. Allvar Gullstrand Swedish Ophthalmologist 1862 - 1930 Professor of Physical & Physiological Optics, University of Uppsala Nobel Prize 1911 for work on optics of eye First “reflex free” ophthamoscope GTT 04
  83. 83. FIRST ATTEMPT AT BINOCULAR VIEW Obs. L eye Obs. R eye S’s eye Combine L and R eye views Observer’s eyes have to be too close
  84. 84. GTT 05
  86. 86. Subject’s eye Observer R Eye L exit pupil R exit pupil Observer L Eye aerial image left-to-right reversed subject’s retina appears reversed L to R SUBJECT’S RETINAAPPEARS REVERSED LEFT TO RIGHT TOP VIEW
  87. 87. Subject’s eye SIDE VIEW sup inf RIP Observer’s eye aerial image top-to-bottom reversed subject’s retina appears reversed top-to-bottom SUBJECT’S RETINA APPEARS REVERSED TOP-TO-BOTTOM
  88. 88. 42 40 mm 50 mm 20 D 1 mm dia exit pupil 2.0 mm MONOCULAR FIELD OF VIEW GTT 04
  89. 89. 20 D 40 Area of binocular view BINOCULAR FIELD OF VIEW GTT 04
  90. 90. SUMMARY Draw a simplified diagram of the optics of the binocular indirect ophthalmoscope. Illumination planes Pupil planes Retinal image planes Be able to explain: Image orientation Field of view Magnification
  91. 91. BIO MAGNIFICATION Maerial image = Peye Plens
  92. 92. GTT/98
  93. 93. Indirect ophthalmology Condensing lenses
  94. 94. Slitlamp biomicroscopy Goldmann triple-mirror lens • Image is upside down View of peripheral fundus
  95. 95. GTT/98 Confocal Scanning Laser Ophthalmoscope
  96. 96. History of ophthalmoscope  Mery in 1704 made first ophthalmoscopic observation of a normal fundus in a drowning cat  Cumming and Brucke in 1846 explained the principles of ophthalmoscopy 102