Distance of distant direct ophthalmoscopy is: March 2013 (a, b, c, d, g, h)
Ans. A i.e. 22 cm Distant direct ophthalmoscopy Used to get a preliminary idea about the status of the ocular media and fundu This should be done routinely before doing a direct ophthalmoscopy Equipment needed - self illuminated ophthalmoscope or plane mirror with a hole in centre 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 Uses Opacities in the ocular media are seen as dark spots in the red glow at the pupillar 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) 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 To differentiate between a mole on the iris and a hole in the iris in oblique illumination, both appear dark in distant direct ophtalmoscopy mole - appears dark hole - red glow is seen 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
22 cm
50 cm
75 cm
100 cm