Direct ophthalmoscope.pptx

you will get information and knowledge about the direct ophthalmic instrument known as ophthalmoscope.
its principle, parts, types, its different filters, techniques, uses, and its method is explained in these slides.

1. Ophthalmoscopy , also called funduscopy, is a test that allows a health professional to see inside the fundus of the eye and other structures using an  ophthalmoscope ( funduscope ). It is done as: Part of an eye examination Part of a routine physical examination Direct Ophthalmoscope

2. ophthalmoscope Ophthalmoscope is a hand held instrument used to examine the fundus. It is used monocularly. It can be used to examine central 7-10 degree of retina. It gives a magnification of 15x which makes the 1.5mm disc appear much larger.

3. Principle

4. Principle The instrument consists of a system of lenses which focus light from an electric bulb on to a mirror where a real image of the bulb filament is formed. The mirror reflects the emitted light in a diverging beam which is used to illuminate the patient's eye. The mirror contains a hole through which the observer views the illuminated eye. The image of the bulb is formed just below the hole so that its corneal reflection does not lie in the visual axis of the observer.

5. Direct ophthalmoscope

6. Field of view The area of retina which can be seen at any one time is called the field of view. It is governed by the projected image of the sight-hole on the retina (the sight-hole being the hole in the mirror or the observer's pupil, whichever is the smaller).

7. SYSTEMS OF Ophthalmoscope Ophthalmoscope consist of two system Illuminating system Viewing system

8. Methods of examination Distance direct ophthalmoscopy Direct ophthalmoscopy

9. Distant direct ophthalmoscopy It is used to get a preliminary idea about the status of the ocular media and fundus This should be done routinely before doing a direct ophthalmoscopy Equipment needed: Self illuminated ophthalmoscope or plane mirror with a hole in center

10. Procedure Should be performed in a semi dark room The ophthalmoscope should be kept at a distance of 20-25 cm from the patient’s eye Normally a red reflex is seen at the pupillary area

11. Uses To diagnose opacities in refractive media To differentiate between a mole on the iris and a hole in the iris To detect a retinal detachment or fundal mass

12. opacities in refractive media Opacities in the ocular media are seen as dark spots in the red glow at the pupillary area The plane of the opacities can be assessed by asking the patient to move the eye from side to side while the examiner is observing the pupillary glow (based on parallax principle)

13. opacities in refractive media Opacities in front of the pupil move in the direction of eye movement Opacities in the pupillary plane do not move Opacities behind the pupillary plane move opposite the direction of eye movement

14. Bruckner test

15. Mole on iris and hole in iris To differentiate between a mole on the iris and a hole in the iris in distant direct ophthalmoscopy Mole – appears dark Hole – red glow is seen

16. RD or fundal mass To detect a retinal detachment or fundal mass Both of them are visible as a grayish reflex It is not possible to differentiate them in distant direct ophthalmoscopy

17. Direct ophthalmoscopy

18. Types of Ophthalmoscopes Traditional Direct Ophthalmoscope Pan Optic Direct Ophthalmoscope

19. Pan Optic Direct Ophthalmoscope Fast, easy entry into small, un-dilated pupils 25° field of view versus the 5° field of view of standard ophthalmoscopes 5X larger view of the fundus vs. standard ophthalmoscopes in an un-dilated eye Greater working distance improves comfort for practitioner

20. Ophthalmoscope Settings Aperture/Filter Dial The aperture/filter dial allows the ophthalmoscope to be used for different purposes. Half light:   If, for example, the pupil is partially obstructed by a lens with cataracts, the half circle can be used to pass light through only the clear portion of the pupil to avoid light reflecting back.

21. Large/Medium/Small light source:   Ophthalmoscopes usually have 2-3 sizes of light to use depending on the level of pupil dilation. The small light is used when the pupil is very constricted (i.e. well lit room, no pupil dilators used). The large light is best if using mydriatic eye drops to dilate. Most commonly in a dark, non-dilated pupil, the medium sized light is used.

22. Red free:  Used to visualize the vessels and hemorrhages in better detail by improving contrast. This setting will make the retina look black and white. Slit beam:  Used to examine contour abnormalities of the cornea, lens and retina. Blue light:  Some ophthalmoscopes have this feature that can be used to observe corneal abrasions and ulcers after fluorescein staining. Grid : Used to make rough approximations of relative distance between retinal lesions.

23. Technique --> Finding the Retina Darken room, ask patient to look at the same point as far as possible in the room (this will help to dilate the pupil). Wedge scope against your cheek with hand and then head/hand/scope should move as one unit. Use your right hand & your right eye to look at the patient’s right eye (Less important if using the Pan Optic).

24. Look through the ophthalmoscope, if you are nearsighted and have taken off your glasses, you may need to adjust the focusing wheel towards the negative/red until what you see at a distance is in focus. Direct the ophthalmoscope 15 degrees from center and look for the red reflex. Simply follow the red reflex in until you see the retina. If you lose the red reflex, come back until you find it again and repeat.

25. To look around the retina using a traditional direct ophthalmoscope, you should "pivot" the ophthalmoscope, angling up, down, left and right. If using the PanOptic , you can slightly "pivot" or ask the patient to look up to see upper retina, down to see lower retina, medial to see medial, latereral to see lateral and finally to look at the light to visualize the macula. 

26. Dilating the Pupil for the Fundoscopic Exam Mydriatic drops Dilate one eye when you start your H & P and by the time you are done you will have a good look. In general Tropicamide is considered the safest. Parasympathetic antagonists: Paralyze circular muscle of iris (mydriasis) and the ciliary muscle (loss of accommodation).

27. Mydriatic drops Tropicamide: 1-2 drops (0.5%) 15-20 minutes before exam; may repeat every 30 minutes PRN. Individuals with heavily pigmented eyes may require larger doses. Cyclopentolate: 1 drop of 1% followed by another drop in 5 min; 2% solution in heavily pigmented iris. Atropine: (1% solution): Instill 1-2 drops 1 hour before the procedure. Homatropine: 1 drop of 2% solution immediately before the procedure; repeat at 10 min intervals PRN.

28. Sympathetic agonists Phenylephrine: 1 drop of 2.5% or 10% solution, may repeat in 10-60 min PRNs

29. Clinical Images of the Retina Normal fundus Pathological Optic Cupping Optic Disc Edema  Arterio-Venous (AV) Nicking Cotton Wool Spots