What is scissoring reflex on retinoscopy?

On retinoscopy, eyes with Keratoconus exhibit a scissor reflex action of two bands moving toward and away from each other like the blades of a pair of scissors, which is almost diagnostic of the condition.

Where is the reflex formed when performing retinoscopy?

light reflected back from the retina. This reflected light is called the retinoscopic reflex (or simply, the “ret reflex”). The ret reflex looks like a red light inside the person’s pupil.

What is Foucault’s principle?

The basic principle of retinoscopy is the Foucault test. In this test, a knife edge placed on the principal axis of an optical system (S) intercepts a bundle of rays coming out of (S). Depending on the position of the knife edge, various distributions of light and shadow can be observed on the anterior surface of (S).

What are the techniques of retinoscopy?

Retinoscopy (Ret) is a technique to obtain an objective measurement of the refractive error of a patient’s eyes. The examiner uses a retinoscope to shine light into the patient’s eye and observes the reflection (reflex) off the patient’s retina.

What is scissor reflex eye?

-The most common sign of keratoconus is a scissor reflex on retinoscopy. The light reflex, instead of being evenly distributed, appears to have a dark centre, thus creating the scissor effect. often described as a scissors reflex (Figure l), whilst. on keratometry, it is seen as distorted mires (Figure. 2).

What is window reflex?

The corneal reflex, also known as the blink reflex or eyelid reflex, is an involuntary blinking of the eyelids elicited by stimulation of the cornea (such as by touching or by a foreign body), though could result from any peripheral stimulus.

What is the reflex stage and projection stage?

The reflex stage – An image of the illuminated retina is formed at the patient’s far-point8. The projection stage – The image at the patient’s far-point islocated by moving the illumination across the fundus and noting the behaviour of the luminous reflexseen by the observer in the patient’s pupil8.

What type of movement is seen while neutralizing a minus power lens?

If the lens has no power – or has been neutralised by placing a lens of equal power but opposite sign against the unknown lens – then there is no image movement.

What is dynamic retinoscopy?

Dynamic retinoscopy is a well described but often overlooked technique that allows rapid. assessment of accommodative ability. The key to the technique is the neutralization of the retinoscopic. reflex that occurs when the patient accommodates on a target adjacent to the retinoscope.