Download to read offline
Uploaded byKafrELShiekh University
mastering visualization of posterior segment
The document outlines techniques and considerations for fundoscopic examinations, including the purpose and methods for assessing the retina. It discusses dilation medications, different lenses for indirect and direct ophthalmoscopy, and the importance of patient cooperation and proper positioning. Various lenses are described for specific retinal examinations, along with their features and applications in conditions like diabetic retinopathy.
More Related Content
Similar to mastering visualization of posterior segment
More from KafrELShiekh University
mastering visualization of posterior segment
- 1. Mohamed Ahmed ELShafie Lecturerof ophthalmology Harvard Medical School Almuni Director of Training Unit 01069201269
- 2. Trying to seeall retina ⚫How much retina is there ⚫How do we measure ⚫Factors that Influence what we see ⚫How do we overcome Cornea ⚫How do we overcome Pupil ⚫How do we overcome spherical shape of Retina
- 3. • ⚫11.5-12.5 sqcms • ⚫Round in shape More temporal than nasal • ⚫Larger in myopes than hyperopes How much retina is there ?!
- 6. PURPOSE OF FUNDOSCOPIC EXAM ⚫Examine thevitreous ⚫Examine the optic nerve ⚫Examine the macula ⚫Examine the vasculature ⚫Examine the peripheral retina ⚫Examine the choroid
- 7.
- 8. Visible Area ofRetina
- 9. Medications used todilate the pupil • ⚫Tropicamide 0.5% or 1% • ⚫Phenylephrine 2.5% • ⚫Cyclopentolate 1% • ⚫Atropine 1% Optimal effect appears 25-30 minutes after administration of dilating drops
- 10. • Contraindications: headinjury requiring monitoring
- 11.
- 12. Types of Images DirectImage Image appears upright when using a directlens Indirect Image Image appears inverted and backwards when using an indirect lens
- 13. Clear Images Dependon Many Factors Doctor • Correct working distance •Steady hand on lens and patient •Exam pattern Illumination Intensity Spot/slit size Ambient light Lens Double aspheric AR coated Appropriate FOV and magnification Patient Patient cooperation Stable gaze/fixation Smooth corneal surface Pupillary dilation
- 14. Selecting the RightLens Design Increases depth of focus
- 15. Importance of AntiReflective Coatings Without Anti-Reflective Coating With Anti-Reflective Coating
- 16.
- 18. Advantages Portable Easy to use Uprightimage Magnification 15x Can use w/o dilation Disadvantages Small field of view Lack of stereopsis Media opacities degrade image
- 20.
- 21. • Look formedia opacities • Cataracts • Corneal scars • Large floaters
- 22. Don’t rub noses… Properposition for central fundus viewing: Right eye to right eye Left eye to left eye
- 23. • It shouldbe performed in semi dark room.
- 24. Direct Ophthalmoscopy technique: Observe: Optic disc VesselsMacula Peripheral fundus Start at optic disc & work radially Be systematic
- 26.
- 27. Proper position for peripheralfundus viewing
- 28.
- 29. • Makes theeye highly myopic by placing a strong convex lens in front in it.
- 34.
- 35.
- 37. Examination of pediatric patients inNeonatal ICU • Proper dilation and anesthesia Cyclopentolate 0.5% -1% placed 10 mins apart x 3 for adequate dilation • Sterile speculum for each eye and pediatric depressors • 28 D or 20 D indirect lenses can be used to view the fundus • Adequate positioning of the infant with help
- 38.
- 39.
- 40.
- 41. Formation of anImage with Lens A biconvex lens forms an inverted virtual image between the observer and the lens.
- 42. Right Working Distance providesthe widest and clearest field of view.
- 46. Fundus biomicrosopy : 90D ⚫Fieldof view: 89 degrees ⚫Magnification: 0.76 ⚫Working distance: 6.5 mm to 7 mm ⚫Features 26 mm diameter ring Good for dynamic fundoscopic exam
- 47. Slit Lamp Stereo Biomicroscopywith 90 Diopter Lens • Illumination angle coaxial system and slit lamp viewing system as far apart to limit reflections • Slit lamp beam width 2-3 mm and length 5-10 mm • Magnification can be adjusted at 10 x or 16 x
- 48. Fundus biomicroscopy: 78D • Fieldof view: 97 degrees • Magnification: 0.93 • Working distance: 8 mm • Features a 26 mm diameter ring Good for dynamic fundoscopic exam
- 49. Fundus contact Biomicrosc opy ⚫ Wider angleof visualization ⚫Coupling agent ⚫Stabilization of view during laser procedures ⚫Dilated pupil ⚫3D relationship between vitreous and Retina
- 50. Volk Quadraspheric lens ⚫130 degreeAspheric surfaces employ high efficiency antireflective coatings, reduces astigmatism across the entire field of view ⚫Inverted and reversed image ⚫Laser spot magnification 1.97 x; image 0.51
- 51. HR wide field lens •160degree Aspheric surfaces with high efficiency antireflective coatings, reduces astigmatism across the entire field of view •High index of refraction allows smaller size and easier to hold in place •Inverted and reversed image •Laser spot magnification 2.0 x; image 0.5 x
- 52. Super Quad Lens •perform retinal photocoagulation • 160 degree super quad lens with Aspheric surfaces employ high efficiency antireflective coatings, reduces astigmatism across the entire field of view • Inverted and reversed image • Laser spot magnification 2.0x x; image 0.5 x
- 53. Trans Equator Lens • 110degree • Good for focal laser • Inverted and reversed image • Laser spot magnification 1.14 x; image 0.7 x • Excellent stereopsis
- 54. • Area Centralis Lens •70degree area centralis lens •Inverted and reversed image •Laser spot magnification 0.94 x; image 1.06X •Excellent for macular laser •Difficult to use in deep set eyes
- 56.
- 57. Pan retinal photocoagulatio n ⚫Super quadwill provide wider field of view and adequate magnification ⚫Gonio Solis used to hold in position ⚫Superior control of patient eye movements
- 58.
- 59. Macular lenses for focallaser • Area centralis or transequator is used for optimal viewing of macula • Goniosol is used as a coupling agent for the lens • Areas of pathology are identified on fundus photos and/ or fluorescein angiography • Magnification and detailed view of the macula allows precise delivery of laser spots for focal laser treatment
- 60.