The optical procedure being done is used for:: (A) Objective refraction, (B) Subjective adjustment of cylinder, (C) Binocular balancing of vision, (D) Subjective refinement of cylinder
Answer is D. Ans. (d) Subjective refinement of cylinderRef: Khurana optics 2/e, p. 153The instrument seen in the image is the Jackson cross cylinder (over the trial frame) - which is used for subjective refinement of cylinder.