Lecture 7: Trial Frame Refraction and Exam Techniques

why do trial frame refraction in LV

1. viewing posture

2. accidental vignetting of pupil in phoropter

3. large lens changes are clunky

4. easy demo and confirmation of Rx changes

determine appropriate staring point by performing _

retinoscopy

T or F: NEVER do ret over PALs

TRUE

build dist rx in trial frame instead

what will autorefractor do to kids' prescription if they're not cyclo'd?

overminus them

should high powered spherical lenses be placed in the front-well of the trial frame or back-well?

back well

if habitual glasses are very scratched, should u build a trial frame or use clip on lenses?

build trial frame

if pt has large RE in glasses, should u build a trial frame or use clip on lenses?

clip on lenses

if the pt has a large cyl axis change on ret, should u build a trial frame or use clip on lenses?

build trial frame

which eye should u start refracting first: good seeing eye or bad seeing eye?

good seeing eye

what type of occlusion to use for a nystagmus pt or young pts w accommodation?

high plus fogging lens

what type of occlusion to use for little kids or extreme eccentric viewing?

stick-on patch or tissue

why start w high powered lenses on initial sphere?

to see if pt is sensitive to blur

show plus or minus lens first?

minus

On initial presentation, you expect your patient to prefer _ if you've selected large enough powered lenses to bracket confidently

plano

what is the total JND power for 20/200

200/100 = 2D

what is the JND sphere lens power for 10/100

100/100 = 1D

cyl JND is _ that of sphere

double