Dynamic Retinoscopy

What is the goal of dynamic retinoscopy?

to measure the magnitude of accommodative response

What is goal of static retinoscopy?

measure refractive error in the ABSENCE of accommodation

When a neutral reflex if found what does the retinoscope coincide with?

the point conjugate with the retina

If the eye is corrected what is the accommodative response?

the recipricol of the distance between the ret and the eye

Accommadative stimulus

recipricol of target distance in meters for an emmetropic eye

What is the procedure for Cross-Nott ret?

Keep the target the same distance from the eye and move the ret till you find neutral

What question is being answered by Cross-Nott ret?

What is patients accommodative response to this stimuli?

Lag of accommodation

patient accommodates less that what is required by the stimulus

Lead of accommodatation

patient accommodates more than what is required by the stimulus

Why can a patient have lag accommodation?

because of depth of field

Formula for stimulus to accommodation

required power of eye- unaccommodatedpower of eye

-how close the target is

Formula for accommodative response

accommodated power-unaccommodated power

-where is patient's eye focused

Required power

theoretical power needed to focus the target of the retina

accommodated power

actual amount the eye's power increases

Other that position of target/eye focus, what else does accommodative stimulus/response take into account?

any uncorrected refractive error

Bells retinoscopy procedure

Keep the retinoscope still and move the target

-change the stimulus of accommodation to get a specific accommodative response

What question is asked by bells retinoscopy?

Waht do I have to do to get patient to fixate at this distance?

Sheard's retinoscopy procedure

both the ret and the target remain fixed while different lenses are put infront of the eye

What is the issue with sheard's retinoscopy?

patients accommodation with relax as soon as you add the first plus lens

Low dynamic neutral

lowest lens that give you neutral reflex

What is low dynamic neutral equal to?

accommodative error

High dynamic neutral

highest lens that gives you neutral reflex

if you add plus lenses then low dynamic neutral is....

lag of accommodation

if you add minus lenses then low dynamic neutral is....

lead of accommodation (this is rare)

How do you determine how much a patient can relax their accommodation?

the difference between high dynamic neutral and low dynamic neutral

Negative Relative Accommodation (NRA)

ability to relax accommodation while maitaining convergence on a target

Formula for NRA

HDN-LDN

Positive Relative Accommodation (PRA)

ability to increase accommodation while maintaining convergence on a target

Positive Relative Vergence (PRV)

ability to increase vergence while maintaining accommodation on a target

Negative Relative Vergence (NRV)

ability to decrease vergence while maintaining accommodation on a target

Monocular Estimate Method (MEM)

lenses are introduced monocularly for very breif periods so accommodation does not have time to change to stimuli

What is the problem with MEM?

we can accommodate to fast to have this method work

Mohindra's Near Retinoscopy

-measures distance refractive error

-used to ret babies instead of cyclopleaging

-preformed in a dark room

-idea is child will fixate on ret but will not have blurr driven accommodation

After ret is done what do you remove from your Monhindra's Near Retinoscopy results?

-1.25 to account for working distnace and tonic accommodation

What is issue with Mohindra's Near Retniscopy?

it does not take into consideration proximal accommodation