Direct and Indirect Ophthalmoscopy

direct ophthalmoscopy versus indirect ophthalmoscopy

Ophthalmoscopy or Fundoscopy is the visualisation of the retina or fundus.

Direct Ophthalmoscope

A direct ophthalmoscope is a device that produces an unreversed or upright image of around 15 times magnification. The direct ophthalmoscope is a critical tool used to inspect the back portion of the interior eyeball, which is called the fundus. Examination is usually best carried out in a darkened room.

As a physician, you should look for alterations in the pigment or color of the fundus as well as changes in the shape and caliber of retinal blood vessels. You should also look for abnormalities in the macula lutea, which is the part of the retina that receives and analyzes light from the center of the visual field. Opacities and macular degeneration of the lens can also be detected through direct ophthalmoscopy.

What is an Indirect Ophthalmoscope?

An indirect ophthalmoscope is a device that produces a reversed or inverted direct images with two to five times magnification. In comparing direct vs indirect ophthalmoscope, the indirect ophthalmoscope delivers a stronger source of light, greater opportunity for stereoscopic inspection of the eyeball interior, and a specifically designed objective lens.

Indirect ophthalmoscopes have proven to be an exceptionally valuable device for the treatment and diagnosis of detachments, holes, and retinal tears. In order for the satisfactory use of an indirect ophthalmoscope, the patient’s pupils must be completely dilated.

Binocular Indirect and Monocular Indirect Ophthalmoscopes

Indirect ophthalmoscopes can be divided into two different categories that include:

  • Monocular indirect ophthalmoscopes
  • Binocular indirect ophthalmoscopes

Monocular Indirect Ophthalmoscopes

Monocular indirect ophthalmoscopes offer a wider field of view and higher magnification levels than the traditional ophthalmoscope. As the name suggests, however, the monocular indirect ophthalmoscope only offers a single view of the eye’s interior. For a physician to properly assess a patient’s ocular condition and fundus, you should have the patient look in multiple directions.

Binocular Indirect Ophthalmoscopes

Instead of only projecting one, binocular indirect ophthalmoscopes project three elements in the eye. As a result, the ophthalmologist, or optometrist can get a three-dimensional rendition of the patient’s interior eye, which facilitates a much more thorough examination.

Direct vs Indirect Ophthalmoscope

While direct and indirect ophthalmoscopes are used to achieve similar goals, these devices have distinct differences. Use the chart below to see the differences between direct vs indirect ophthalmoscopes.

While direct and indirect ophthalmoscopes are used to achieve similar goals, these devices have distinct differences. Use the chart below to see the differences between direct vs indirect ophthalmoscopes.

Indirect OphthalmoscopyDirect Ophthalmoscopy
Observation view field diameterWide view (approx. 37o in diameter)Small view (approx. 10o in diameter)
MagnificationFive times when +13D condensing lense is usedApprox. 15 times
Structures viewedPeripheral retina seenCentral retina only
BrightnessMore brightnessLess brightness
StereopsisBinocular indirect provides superior stereopsisImage created isn’t stereoscopic
Image of fundusInverted and virtual imageErect and real image
Scleral indentationEasily achieved in binocular indirect ophthalmoscopyDifficult
Retina anterior to the equatorMore visualCan be seen with difficulty
Visibility in hazy mediaBetterPoor

MCQ 1) Area of fundus seen with direct ophthalmoscope is- (NEET/DNB pattern)
A)

a)1 DD

b) 2 DD

c) 3 DD

d) 4 DD

MCQ 2} The magnification obtained with a direct ophthalmoscope  is- (AL 06, AIIMS may 05)

a) 5 times

b) 10 times

c) 15 times

d) 20 times

MCQ 3} Image seen by indirect ophthalmoscopy is- (PGI Dec 00 )

a) Inverted + Virtual

b) Erect + virtual

c) Inverted +Real

d) Erect + Real

MCQ 4} Image formed in direct opthalmoscopy is- (PGI Dec 09)

a) Real and erect

b) Real and Inverted

c) Virtual and erect

d) Virtual and inverted

MCQ 5} Magnification in Indirect ophthalmoscopy-(PGI Dec 06)

a) Depends on power of lens used

b) Depends on refractive error of pt

c) Independent of refractive error of pt

MCQ 6} Periphery of retina is visualized by – (PGI Dec 02)

a) Indirect ophthalmoscopy

b) Direct ophthalmoscopy

c) Goniocopy

d) Contact lens

MCQ 7} Indirect opthalmoscopy detects A/E-(AIIMS Sep 96)

a) Examination of ora serrta

b) Retinal periphery

c) Examination of vitreous base

d) Examination of fovea

MCQ 8} Indirect ophthalmoscopy is done for – (PGI June 97)

a) Central retina

b) Periphery of retina

c) Angle of ant. chamber

d) Sclera

MCQ 9} All are true about indirect ophthalmoscope except – (PGI june 97)

a) Image is real and inverted

b) Details of fundus can be seen even with slightly

hazy media

c) Magnification is more than direct ophthalmoscope

d) Used for seeing periphery of fundus

MCQ 10} Distant direct ophthalmoscopy  is done at a distance of- (AI 99,AIIMS Dec 94)

a) 20 cm

b) 25 cm

c) 50 cm

d) 100 cm

Hope the article covering direct and indirect ophthalmoscope was helpful. Do test yourself in the MCQs and comment below. Correct answers will be posted soon.

Also read these ophthalmology articles

Leave a Comment

Your email address will not be published.