When we project light on the retina with the retinoscope, the retina is illuminated as if it were a luminous body.
The emerging rays of light from the retina are being observed as a retinal reflex in the patient’s pupil while looking through the peephole in the retinoscope which moves if we sweep the streak across the pupil.
The moving reflex should be analyzed under the following categories:
1. Speed
2. Brilliance
3. Width.
SPEED
The speed of reflex movement is an indicator of the amount of refractive error. Reflex moves slower when the neutrality is far away or you are far from the far point.
As you get closer to the neutrality, the speed of reflex movement becomes rapid, and on reaching the neutrality, no movement is seen, i.e. the pupil fills completely.
It implies that fast moving reflex is seen in case of smaller refractive error and slow moving reflex is seen in case of large refractive error.
BRILLIANCE
The brilliance of the reflex also indicates the amount of the refractive error.
A bright reflex is being seen when you approach the neutrality and a dull reflex is being seen when you are far away from the neutrality, i.e. away from far point.
This implies larger errors have a dull reflex and smaller errors have a bright reflex. The brilliance of reflex is also different in case of “with motion reflex” and “against motion reflex”.
It is comparatively dull in case of against motion reflex at any comparable distance from the far point.
WIDTH
The change in width of the reflex band is noticed as you approach neutrality. It is narrow when you are far away from the neutrality and is widest, i.e. entire pupil fills up, when the neutrality is achieved.The width of the band increases gradually from narrow to wide as you approach the far point.