Stenopaeic slit can be used for all except
Ans. (c) Corneal tattooingRef: Elkington Optics 4/e, p. 117-118Uses of Stenopaeic SlitDetermination of meridian of optical iridectomy - in patients with corneal scar or lenticular opacityTo diagnose cases of cataract, by differentiating between colored halos caused in Angle closure glaucoma and cataractDetermine power and axis of cylinder - The slit aperture acts as an elongated 'pin-hole', only allowing light in the axis of the slit to enter the eye. Hence, when the slit lies in one principal axis of the astigmatic eye, the second line focus is eliminated and the blur of Sturm's conoid reduced thus allowing a clearer image to be formed.
Finchams test
Iridectomy
Corneal tattooing
Axis of cylindrical refractory error
Elementary Optics