(3) Objective Refraction Retinscopy

Question 1

What are indications for objective refraction

Answer 1

• Low vision patients
• infants/pre-verbal children
• intellectually disabled patients
• non-communicating patients

Question 2

What are the 2 types of retinoscopy techniques

Answer 2

Static and dynamic

Question 3

Use and importance of retinoscopy

Answer 3

• eliminates bias in patient’s response

- eliminates language barrier

Question 4

define static retinoscopy

Answer 4

measuring refractive error at a state of rest

Question 5

How does static retinoscopy work

Answer 5

-fixating at infinity (6m) with accommodation relaxed

Question 6

procedures before retinoscopy

Answer 6

-check pd and va (ua,a,ou)
-fit trial frame
control accommodation
-reduce room light
-target
-wdl (+2.00=50cm, +1.50=67cm)
-fog non tested eye

Question 7

explain fogging lens

Answer 7

more +ve than required for px to see clearly.

too clear=add plus, too blur=add minus

Question 8

explain fixation target

Answer 8

should be blur but visible

Question 9

Two types of retinoscope

Answer 9

Spot and streak

Question 10

instructions for retinoscopy

Answer 10

• im going to check your power
• i will shine a light
• look at target, not light
• let me know if blocked
• keep both eyes open

Question 11

Types of reflex movement

Answer 11

• against > myopic > -ve lens

- with > hyperopic > +ve lens

Question 12

Reflex movement for high myopia

Answer 12

Broader
-larger than pupil
-hard to see the reflex boundary
slower
dimmer
-speed and movement harder to judge

Question 13

Reflex movement for high hyperopia

Answer 13

Thinner, dimmer

Question 14

Reflex when reaching neutrality, and at end point

Answer 14

• illuminated retina area becomes smaller
• bright fast wide
• with movement observed when move closer

Question 15

Explain far point concept

Answer 15

Accommodation relaxed -> point in space that is conjugate with the ret = far point

Question 16

How does WDL operate in far point concept

Answer 16

Allows far point to fall on retinoscope instead of usual at infinity hence making retinoscope as if at infinity.
+2.00 (50cm) +1.50 (67cm)

Question 17

How many far points will spherical and astigmatic ametropia have

Answer 17

1, 2 respectively