Techniques of fundus examination include direct ophthalmoscopy, indirect ophthalmoscopy, and slit-lamp biomicroscopic examination using various lenses. Direct ophthalmoscopy provides an upright 15x magnified view of the fundus but has a limited field of view. Indirect ophthalmoscopy uses a condensing lens to produce an inverted real image with a wider field of view, allowing examination of the peripheral retina. Slit-lamp biomicroscopy employs contact lenses or small diameter lenses like a +78D or +90D to provide magnified views of the posterior pole under illumination.

1. TECHNIQUES OF FUNDUS
EXAMINATION
DIRECT & INDIRECT OPHTHALMOSCOPY
Dr. VINIT KUMAR

2. Techniques of fundus examination include
• A. Ophthalmoscopy &
• B. Slit-lamp biomicroscopic examination of the fundus by :
• • Indirect slit-lamp biomiscroscopy
• • Hruby lens biomicroscopy ( 60 D, 78D, 90D )
• • Contact lens biomicroscopy.

3. Direct ophthalmoscope

4. Different filter / aperature for examination

5. A. OPHTHALMOSCOPY
• 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 &
detect the opacities of ocular media. The ophthalmoscope was invented by
Babbage in 1848, h & it was reinvented by von Helmholtz in 1850.
• Three methods of examination in vogue are:
• DDO Distant Direct Ophthalmoscopy
• DO Direct ophthalmoscopy
• IDO Indirect ophthalmoscopy.

6. 1. Distant Direct Ophthalmoscopy
• It should be performed routinely before the direct ophthalmoscopy, as it gives
a lot of useful information .
• Procedure. The light is thrown into patient’s eye sitting in a semi-darkroom,
from a distance of 20–25 cm & the features of the red glow in the pupillary
area are noted.
• Applications of distant direct ophthalmoscopy include:
• i. To diagnose opacities in the refractive media

7. DDO uses :
• Any opacity in the refractive media is seen as a black shadow in the red
glow. The exact location of the opacity can be determined by observing
the parallactic displacement. For this, the patient is asked to move the eye
up and down while the examiner is observing the pupillary glow.
• Opacities in the pupillary plane remain stationary
• Opacities in front of the pupillary plane move in the direction of the
movement of the eye
• Opacities behind it will move in opposite direction

8. • ii. To differentiate between a mole & a hole of the iris. Hole give red
reflex through DDO & mole give black shadow through DDO
• iii. To recognize detached retina or a tumour arising from the fundus .

9. DIRECT OPHTHALMOSCOPE
• 2. Direct Ophthalmoscopy
• It is the most commonly used method for routine fundus examination.
• Optics. The modern direct ophthalmoscope works on the basic optical
principle of glass plate ophthalmoscope introduced by von Helmholtz

10. optics of direct ophthalmoscope
• Characteristics of image formed.
• In direct ophthalmoscopy, the image is erect, virtual & about 15 times
magnified in emmetropes (more in myopes & less in hypermetropes).

11. technique of DO
• Direct ophthalmoscopy should be performed in a semi-darkroom with
the patient seated & looking straight ahead, while the observer standing or
seated slightly over to the side of the eye to be examined .
• Patients right eye should be examined by the observer with his or her right
eye and left with the left eye .

12. Technique of direct ophthalmoscopy :
• The observer should reflect beam of light from the ophthalmoscope into
patient’s pupil. Once the red reflex is seen the observer should move as
close to the patient’s eye as possible (theoretically at the anterior focal
plane of the patient’s eye, i.e., 15.4 mm from the cornea).
• Once the retina is focused the details should be examined systematically
starting from disc, blood vessels, the four quadrants of the general
background & the macula

13. Distance direct & direct ophthalmoscopy

14. indirect ophthalmoscopy ( IDO )

15. IDO : INDIRECT OPHTHALMOSCOPE ( principle )
• 3. Indirect Ophthalmoscopy
• Indirect ophthalmoscopy introduced by Nagel in 1864, is now a very
popular method for examination of the posterior segment.

16. Optical principle of indirect ophthalmoscope
• The principle of indirect ophthalmoscopy is to make the eye highly
myopic by placing a strong convex lens in front of patient’s eye so that
the emergent rays from an area of the fundus are brought to focus as a
real, inverted image between the lens & the observer’s eye, which is
then studied

17. Characteristics of image formation in IDO
• The image formed in indirect ophthalmoscopy is real, inverted &
magnified.
• Magnification of image depends upon the dioptric power of the convex lens,
position of the lens in relation to the eyeball & refractive state of the eyeball.
• About 2.5 times magnification & 35° or 8 disc-diameter field of view is
obtained with a +20D lens.
• With a stronger lens, image will be smaller, but brighter & field of vision will
be more.

18. Prerequisites for IDO
• Prerequisites.
• (i) Darkroom
• (ii) Source of light & concave mirror or self-illuminated indirect
ophthalmoscope,
• (iii) Convex lens (now-a-days commonly employed lens is of +20D)
• (iv) Pupils of the patient should be dilated.

19. IDO

20. TECHNIQUE :
• Technique. Patient is made to lie in the supine position, with one pillow on a
bed or couch & instructed to keep both eyes open. The examiner throws the
light into patient’s eye from an arm’s distance (with the self-illuminated
indirect ophthalmoscope which is applied with head band ) .
• Keeping his or her eyes on the reflex, the examiner then interposes the
condensing lens (+20D, routinely) in the path of beam of light, close to
patient’s eye & then slowly moves the lens away from the eye (towards
himself) until the image of the retina is clearly seen .

21. Procedure to do IDO :
• The examiner moves around the head of the patient to examine different
quadrants of the fundus.
• He or she has to stand opposite the clock hour position to be
examined, e.g., to examine inferior quadrant (around 6 O’ clock meridian)
the examiner stands towards patient’s head (12 O’clock meridian) & so on.
• By asking the patient to look in extreme gaze, & using scleral indenter,
the whole peripheral retina up to ora serrata can be examined

22. APPLICATIONS & Difficulties in indirect ophthalmoscopy (IDO)
• Applications: Indirect ophthalmoscopy is essential for the assessment &
management of retinal detachment ( RD ) & other peripheral retinal lesions
.
• 1. The technique is difficult & can be mastered by hours of practice.
• 2. Reflexes from the corneal surface can be decreased by holding the
condensing lens at a distance equal to its focal length from the anterior
focus of the eye .
• 3. Formation of reflexes by the two surfaces of convex lens can be eliminated
by slightly tilting the lens & use of aspheric lens.

23. Advantages of the binocular indirect ophthalmoscope are:
• 1. Visualization through hazy media is possible
• 2. Field of view is much larger than Direct ophthalmoscopy
• 3. Examination of peripheral retina up to ora serrata is possible
• 4. Depth perception of the lesion is possible due to stereopsis
• 5. Visualization of fundus in very high refractive error is also possible

24. SLIT-LAMP BIOMICROSCOPIC EXAMINATION OF THE
FUNDUS
performed after full mydriasis using a slit-lamp
• 1. Indirect slit-lamp biomicroscopy.
• Using +78 D or +90 D small diameter lens is presently the most commonly
employed technique for biomicroscopic examination of the posterior pole
of fundus.
• Similar to binocular indirect ophthalmoscopy, the image formed is inverted,
real & magnified .

25. • 2. Hruby lens biomicroscopy.
• Hruby lens is a planoconcave lens with dioptric power 58.6D .
• This lens provides a small field with low magnification & cannot visualize
the fundus beyond equator .

26. 3. Contant lens biomicroscopy can be performed by following lenses:
• • Posterior fundus contact lens is a modified Koeppe’s lens .
• The image produced by it is virtual & erect.
• • Goldmann’s three-mirror contact lens consists of a central contact
lens & three mirrors placed in the cone, each with different angles of
inclination .
• With this the central as well as peripheral parts of the fundus can be
visualized

27. Slit lamp biomicrosopy ( fundus evaluation)

28. Slit lamp biomicroscopy

29. OTHER LENSES USED FOR FUNDOSCOPY

30. fundus evaluation

31. Difference between IDO & DO

32. What are the other methods of fundus
examination?
• In addition to ophthalmoscopy fundus can also be examined by focal
illumination using a slit-lamp biomicroscope and any of the following
lenses:
• • Hruby lens
• • Posterior fundus contact lens
• • Goldmann’s three-mirror contact lens
• • +78 D & +90 D small diameter lenses.

33. Questions
1. When and who invented the direct ophthalmoscope?
• Babbage in 1848.
2. Who reinvented and popularised the ophthalmoscope?
• von Helmholtz in 1850.
3. At what distance distant direct ophthalmoscopy is performed?
• 20–25 cm.
4. What are the uses (applications) of distant direct ophthalmoscopy?
• 1. To diagnose opacities in the ocular media.
• 2. To differentiate between a mole and a hole of the iris
• 3. To recognize a detached retina.
• 4. To recognize a subluxated lens.

34. home work ??
• 5. At what distance ‘direct ophthalmoscopy’ should be performed?
As near to the patient’s eye as possible.
• 6. What are the features of the image formed in direct ophthalmoscopy?
The image formed is erect, virtual and about 15 times magnified in an emmetrope.
• 7. When and who invented the indirect ophthalmoscopy?
Nagel in 1864.
• 8. What is the principle of indirect ophthalmoscopy?
• The principle of indirect ophthalmoscopy is to make the eye highly myopic by placing a
strong convex lens in front of the patient’s eye so that emergent rays from an area of the
fundus are brought to focus as a real, inverted image between the lens and the observer’s
eye

35. Questions ..?
• 9. What is the power of the convex lens most commonly used in indirect
ophthalmoscopy?
+20 D.
• 10. Name the common diseases of the optic disc which can be diagnosed on direct
ophthalmoscopy.
• • Papillitis
• Papilloedema • Optic atrophy • Glaucomatous cupping

36. Questions ..?
• 11. Name some few common retinal disorders which are diagnosed by direct/indirect
ophthalmoscopy ?
• • Diabetic retinopathy
• • Hypertensive retinopathy • Retinal detachment • Retinitis pigmentosa.
• 12. What are the advantages of direct ophthalmoscope over indirect ophthalmoscopy?
• 1. It is a handy procedure.
• 2. Easy to perform.
• 3. Allows examination of the minute details of the approachable lesion, since image formed is 15 times
magnified.
• 4. Orientation and understanding of the lesion is easy as the image formed is erect

37. HOME WORK…
• 14. What are the advantages of indirect ophthalmoscopy over direct
ophthalmoscopy?
• 1. It allows a stereoscopic view of the fundus.
2. It allows examination in hazy media.
3. Periphery of the retina up to ora serrata can be examined.
• 15. What are the characteristics of the image formed in indirect ophthalmoscopy?
• It is real, inverted, magnified about 2.5 times when +20 D lens is used & image is formed
between the convex lens & the observer.

38. LAST SLIDE ……
Thank you!!!