This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Miscellaneous, Subject name: Ophthalmology
Use of stenopaeic slit are all except:- 
Select and explain. 
A. Fincham's test, B. Corneal tattooing, C. Optical Iridectomy, D. To find out the axis in astigmatism
B: Corneal tattooing
Answer: B: Corneal tattooing 
Explanation: *The Stenopic slit found in all the trial sets is 1-2 mm by 15-35 mm in size. It splits an opaque disc into two halves. *It has many uses in Ophthalmology. *Fincham test is used to differentiate that coloured halos are due to early cataract or acute congestive glaucoma related corneal decompensation. * A stenopic slit is passed across the pupil& halos are observed. If those are broken halos , cataract is the most common cause. If brightness is reduced but halos are intact, cornea is the common cause. *Stenopic slit is useful in finding out the axis of the cylinder. *Stenopic slit is used in cases of corneal opacities to find out the optimal site for optical iridectomy. After dilating the pupil with a mydriatic, the slit is rotated in front of the eye and the axis which gives maximum clarity is chosen for optical iridectomy. Ref: Parson's Diseases of the eye, 22nd/e p.204