Ophthalmoscope new-1.pptx.................................

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1. Topic- Ophthalmoscope By- Akanksha Deep Demonstrator DOPT

2. Introduction Ophthalmoscopy is a clinical examination of the interior of the eye by means of an ophthalmoscope It is primarily done to assess the state of fundus and detect the opacities of ocular media The ophthalmoscope was invented by Von Helm- holtz in 1850

3. Structures of the Retina

4. Posterior Pole of fundus

5. Macula I t is responsible for our central vision, most of our  colour vision Specialized region of retina Diameter- 5.5mm Location- Temporal margin of Disc Colour- yellow; deep pigmented

6. Methods of Examination Direct Ophthalmoscopy Indirect Ophthalmoscopy

7. Direct Ophthalmoscopy It is the most commonly practiced method for routine fundus examination A convergent beam of light is reflected into the patients pupil The emergent rays from any point of the patients fundus reach the observers retina through the viewing hole in the ophthalmoscope

8. Direct

9. The emergent rays from the patients eye are parallel and brought to focus on the retina of the emmetropic observer when accommodation is relaxed The image is erect, virtual and about 15 times magnified in ememetropes

10. Technique It should be performed in a semi dark room with the patient seated and looking straight ahead, while the observer standing or seated slightly over to the side of the eye to be examined by the observer with his or her right eye and left with the left

11. The observer should reflect beam of light from the ophthalmoscope into patients pupil Once the red reflex is seen the observer should move as closer to the patients eye as possible Once the retina is focused the details should be examined systematically starting from Disc Blood vessels Four quadrant of the general background Macula

12. A red- free filter makes the red elements very dark so that vessels and pinpoint hemorrhages stand out clearly A blue filter is used as a hand light source for fluorescein staining of the cornea and used in fluorescein Angiography A fixation star, a dot or a star- shaped figure is used to determine the patient’s fixation

13. Parts of direct ophthalmoscope

14. Indirect Ophthalmoscope It is very popular method for examination of posterior segment introduced by Nagel in 1864 Principle – To make the eye highly myopic by placing a strong convex lens in front of patients eye so that the emergent rays from an area of the fundus are brought to the focus as a real, inverted image between the lens and the observers eye +2 D lens is used in eye piece for accommodation relaxation

15. Indirect

16. Characteristics – magnification of image depends upon the dioptric power of the convex lens, position of the lens in relation of the eyeball and refractive state of the eye It forms a real and inverted image

17. Characterstics An inverted reverse real image Magnification= 2 to 4x Field of view = 40 to 50 degrees Working distance = 40 to 50 cm Good illumination & stereopsis Ease of use with scleral indenter Lenses from 14 to 30 D range

18. Parts of Indirect Ophthalmoscope

19. Technique Adjust head band Eye pieces close to the pupil& perpendicular to pupillary axis Adjust IPD Condensing lens between thumb & index finger Silver ring side of lens towards the patient’s eye Eye rotates in the direction of the quadrant to be examined

20. 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

21. Uses of filters Green light- Nerve fiber layer , blood vessels Red light- P igmentary abnormalities Blue light- angiography Yellow filter- reduces photophobia

22. Fundus Examination The fundus of the eye is the interior surface of the eye opposite the lens includes the retina, optic disc, macula, fovea, and posterior pole 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

23. Fundus Charting Amsler - dubois Chart 3 concentric circle Inner- equator Middle- ora serrata Outer- pars plana Radial lines to describe the location of fundus finding in clock

24. Macular Degeneration

25. Scleral Indentation To examine periphery between equator and oraserrata by creating a mound to view Accessories- Thimble scleral depressor Pencil type depressor Cotton tipped applicator

26. Slit lamp Bimicroscopy

27. Condensing Lens Advantages Larger field of visible retina 3D stereoscopic view Useful in hazy media because of its bright light Disadvantages Impossible with small pupils Uncomfortable with intense light and scleral indentation

28. Thank You