Positive and Negative relative
accommodation (NRA-PRA)
purpose of NRA/PRA? - answer increase and relax accommodation while maintaining a
constant vergence.
What do the results of NRA/PRA help determine? - answerNear prescription
What type of lenses are used when performing NRA and why? - answerplus lenses in
order to relax accommodation
What type of lenses are used when performing PRA and why? - answerminus lenses
are used in order to increase the accommodative response
Set up for NRA/PRA? - answerbright illumination while pt wears DISTANCE refraction in
phoropter
Target for NRA/PRA? - answerone line of letters above near visual acuity. set at 40cm.
NRA (negative relative accommodation) - answershould be performed first. add plus
lenses binoculary in front of each eye until point of FIRST BLUR. total amt added =
NRA. note that this should be tested with the patient's distance refraction in horopter
(after JCC)
PRA (positive relative accommodation) - answeradd minus lenses binoculary in front of
each eye until point of FIRST BLUR. total amt added = PRA. note that this should be
tested with the patient's distance refraction in horopter (after JCC)
when should a suppression check (physiological diplopia) be performed? - answerif the
results reach the expected values of (+/-2.50). if results are greater than +/-3.00 STOP
TESTING AND RECORD.
recording - answeralways NRA/PRA
ex:
NRA/PRA +2.75/-1.50 c suppression check
When should a tentative add be placed in the phoropter before performing NRA/PRA?
(Near base) - answerPresbyopic patients. It should always be recorded if something
other than manifest refraction (JCC) is used.
accommodation (NRA-PRA)
purpose of NRA/PRA? - answer increase and relax accommodation while maintaining a
constant vergence.
What do the results of NRA/PRA help determine? - answerNear prescription
What type of lenses are used when performing NRA and why? - answerplus lenses in
order to relax accommodation
What type of lenses are used when performing PRA and why? - answerminus lenses
are used in order to increase the accommodative response
Set up for NRA/PRA? - answerbright illumination while pt wears DISTANCE refraction in
phoropter
Target for NRA/PRA? - answerone line of letters above near visual acuity. set at 40cm.
NRA (negative relative accommodation) - answershould be performed first. add plus
lenses binoculary in front of each eye until point of FIRST BLUR. total amt added =
NRA. note that this should be tested with the patient's distance refraction in horopter
(after JCC)
PRA (positive relative accommodation) - answeradd minus lenses binoculary in front of
each eye until point of FIRST BLUR. total amt added = PRA. note that this should be
tested with the patient's distance refraction in horopter (after JCC)
when should a suppression check (physiological diplopia) be performed? - answerif the
results reach the expected values of (+/-2.50). if results are greater than +/-3.00 STOP
TESTING AND RECORD.
recording - answeralways NRA/PRA
ex:
NRA/PRA +2.75/-1.50 c suppression check
When should a tentative add be placed in the phoropter before performing NRA/PRA?
(Near base) - answerPresbyopic patients. It should always be recorded if something
other than manifest refraction (JCC) is used.
