Retinoscopy is a technique to obtain an objective measurement of the
refractive error
Refractive error is a problem with focus (optics), focusing light accurately on the retina due to the shape of the eye and/or cornea. The most common types of refractive error are myopia, near-sightedness, hyperopia, far-sightedness, astigmatis ...
of a patient's
eyes
An eye is a sensory organ that allows an organism to perceive visual information. It detects light and converts it into electro-chemical impulses in neurons (neurones). It is part of an organism's visual system.
In higher organisms, the ey ...
.
How It Works
The examiner uses a retinoscope to shine light into the patient's eye and observes the reflection (reflex) off the patient's
retina
The retina (; or retinas) is the innermost, photosensitivity, light-sensitive layer of tissue (biology), tissue of the eye of most vertebrates and some Mollusca, molluscs. The optics of the eye create a focus (optics), focused two-dimensional ...
. While moving the streak or spot of light through the pupil across the retina, the examiner observes the relative movement of the reflex or manually places lenses over the eye (using a
phoropter
A phoropter or refractor is an ophthalmic testing device. It is commonly used by eye care professionals during an eye examination, and contains different lenses used for refraction of the eye during sight testing, to measure an individual's ref ...
or
trial frame
A trial frame is a tool used by ophthalmic professionals like ophthalmologists and optometrists. It is basically an adjustable spectacle frame with multiple cells, used to hold corrective lenses, and other accessories in subjective refraction (f ...
and trial lenses) to "neutralize" the reflex.
Static Retinoscopy
Static retinoscopy is a type of retinoscopy used in determining a patient's refractive error. It relies on
Foucault knife-edge test, which states that the examiner should simulate
optical infinity to obtain the correct refractive power. Hence, a power corresponding to the working distance is subtracted from the gross retinoscopy value to give the patient's
refractive condition, the working distance lens being one which has a focal length of the examiner's distance from the patient (e.g. +1.50
dioptre
A dioptre ( British spelling) or (American spelling), symbol dpt or D, is a unit of measurement with dimension of reciprocal length, equivalent to one reciprocal metre, . It is normally used to express the optical power of a lens or curved mi ...
lens for a 67
cm working distance).
Myopes display an "against" reflex, which means that the direction of movement of light observed from the retina is a different direction to that in which the light beam is swept.
Hyperopes, on the other hand, display a "with" movement, which means that the direction of movement of light observed from the retina is the same as that in which the light beam is swept.
Static retinoscopy is performed when the patient has relaxed accommodative status. This can be obtained by the patient viewing a distance target or by the use of
cycloplegic drugs (where, for example, a child's lack of reliable fixation of the target can lead to fluctuations in
accommodation and thus the results obtained). Dynamic retinoscopy is performed when the patient has active accommodation from viewing a near target.
Uses
Retinoscopy is particularly useful in prescribing corrective lenses for patients who are unable to undergo a subjective refraction that requires a judgement and response from the patient (such as children or those with severe intellectual disabilities or communication problems).
In most tests however, it is used as a basis for further refinement by subjective refraction. It is also used to evaluate
accommodative ability of the eye and detect latent
hyperopia
Far-sightedness, also known as long-sightedness, hypermetropia, and hyperopia, is a condition of the eye where distant objects are seen clearly but near objects appear blurred. This blur is due to incoming light being focused behind, instead o ...
.
["Clinical Refraction" by Irvin Borish. The Professional Press, Chicago, Ill. 3rd edition 1970. p.700]
See also
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Eye examination
An eye examination, commonly known as an eye test, is a series of tests performed to assess Visual acuity, vision and ability to Focus (optics), focus on and discern objects. It also includes other tests and examinations of the human eye, eyes. ...
*
Ophthalmoscope
Ophthalmoscopy, also called funduscopy, is a test that allows a health professional to see inside the fundus of the eye and other structures using an ophthalmoscope (or funduscope). It is done as part of an eye examination and may be done as part ...
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Monocular estimate method
The monocular estimate method or monocular estimation method is a form of dynamic retinoscopy widely used to objectively measure accommodative response.Tassinari JT. "Monocular estimate method retinoscopy: central tendency measures and relationsh ...
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Red reflex
The red reflex (also called the fundal reflex) refers to the reddish-orange reflection of light from the back of the eye, or fundus, observed when using an ophthalmoscope or retinoscope. The red reflex may be absent or poorly visible in people ...
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Eye care professional
An eye care professional is an individual who provides a service related to the eyes or vision. It is any healthcare worker involved in eye care, from one with a small amount of post-secondary training to practitioners with a doctoral level of edu ...
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Dispensing optician
An optician is an individual who fits glasses or contact lenses by filling a refractive prescription from an optometrist or ophthalmologist. They are able to translate and adapt ophthalmic prescriptions, dispense products, and work with accessor ...
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Ophthalmologist
Ophthalmology (, ) is the branch of medicine that deals with the diagnosis, treatment, and surgery of eye diseases and disorders.
An ophthalmologist is a physician who undergoes subspecialty training in medical and surgical eye care. Following a ...
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Optometrist
Optometry is the healthcare practice concerned with examining the eyes for visual defects, prescribing corrective lenses, and detecting eye abnormalities.
In the United States and Canada, optometrists are those that hold a post-baccalaureate f ...
*
Orthoptist
Orthoptics is a profession allied to the eye care profession. Orthoptists are the experts in diagnosing and treating defects in eye movements and problems with how the eyes work together, called binocular vision. These can be caused by issues with ...
References
External links
Slide show of retinoscopyFoucault testRetinoscopy simulator online
{{Eye procedures
Diagnostic ophthalmology
Ophthalmic equipment