What is contrast?
It is created by the difference in luminance from two adjacent surfaces.
According to Michelson,
Dynamic retinoscopy is also called Near Retinoscopy because it is done while the patient is focusing on a near target(In accommodated state). The main purpose of Dynamic Retinoscopy is to find out the accommodative response of the patient(lag or lead or normal). There are different methods of performing Dynamic Retinoscopy.
To understand the clinical application of Conoid of Sturm, we need to understand its basic optics.
In simple words, we can say ” Conoid of sturm is just a representation of how rays are refracted through two different powered meridians” (eg: a sphero- cylindrical lens). So, instead of one focal point, they form two focal lines.
Static Retinoscopy can be done in two ways; using a working distance (WD) lens in front of the patient’s eye or without it.
A working distance lens is used to compensate for the distance between the examiner and the patient’s eye. Usually, the working distance is taken as arm length i.e 66cm (+1.50DS)