Retinoscopy Flashcards
Types of retinoscopy
Dynamic - Nott retinoscopy, MEM, bell and book retinoscopy
Static
Another RET method
Ulster cube can tell you dioptres on front of the cube and can do RET and measure with this. Can measure lag and lead with RET at same time. Set front to what distance response was and lock this there and lock at position of there normal reading distance. Measure at 25cms. Only use in abnormal cases of lead as they need treatment and monitoring.
What is static retinoscopy OBJ
Static retinoscopy requires the patient have relaxed accommodation which can be achieved by focusing on a distant object or through cycloplegic agents
What is dynamic retinoscopy
Dynamic retinoscopy requires the patient have active accommodation by focusing on a near object and is useful to evaluate the effectiveness of accommodation
Retinoscopy components
RET result
Distance correction (+1.50) to sphere
Power cross
What is accommodative lag
the response lags behind the stimulus- most kids and adults of 0.5-0.75 if 4 dioptres the accommodative lag is 3.5 dioptres and retinal image experiences 0,5- 0.75 dioptres of blur. Blur not seen when move from distance to near and vice versa.
What is accomodative lead
atypical response e.g. accommodative spasm and thus needs to be treated
What is normal accomodative lag
Normal results are between +0.50 and +1.00
Before testing ensure that
Ensure sleeve is down
Phoropter should be level and pupils centred
Maintain position of 15 degrees from line of light
Patients eyes fixated on object not light
Non cycoplegic
DR- Nott method
The target is a block of 6/6 letters positioned 16 inches from the patient. It is held in place by the doctor, by an assistant or on a scale. The patient must wear their distance correction lenses, and they see the target binocularly. The retinoscope is placed beside the target, and the reflex movement is observed.
Aims of retinoscopy
find reversal point for given stimulus, without the use of additional lenses. Allows for the detection of abnormal responses such as incomplete, sluggish, or momentary accommodation. Useful in high hyperopia or possible accommodative insufficiency, downs have poor accommodative response.
DR- Monocular estimate method
The target is a series of cards with a central aperture attached to a retinoscope. The cards have letters with varying sizes arranged around the opening. The patient is required to keep the targets clear, and the examiner observes the reflex. Lenses ar e used to neutralize the reflex, rather than moving the retinoscope back and front. If the movement is with, add “+ lenses”; if it is against add “- lenses” until a neutral reflex is achieved.
DR- Bell retinoscopy
The test requires a 3-D observing target and a small, greatly reflective bell hanging from a cord. The examiner holds the string with the dangling bell while moving it closer to or further from the patient at a speed lesser than 2 inches/second. The retinoscope is placed at a still position about 20 inches, where the patient observes the target as the clinician notes the reflex direction. The target is drawn nearer to the patient, and the movement shifts from “with” to “against.” The target is shifted from the patient until the examiner observes a “with” motion.
DR- Book retinoscopy
It is also known as Getman retinoscopy. The patient is given reading material, and retinoscopy is performed as the subject reads aloud. Information is collected in real-time with a task close to their normal work situation.
The response levels can be at either free reading level (it is desirable, and reflex varies from neutral to with), instructional level (more demanding than the free level and reflex varies fast against motion) or frustration level (although the subject is focused, there is an improper interpretation of information).
Pros of retinoscopy
cheap, portable, accurate technique, objective, can be used from 2-3 years old
