accommodation Flashcards
(26 cards)
ketotifen 0.25%
alaway
ketotifen 0.35%
Zaditor
What is this patient’s calculated AC/A ratio?
PD: 58mm
Habitual
OD: -4.00 -2.00 x 180 20/20
OS: -4.75 -3.00 x 180 20/20
CT
D: small XP
N: mod XP
VonGaefe
D: 3XP
N: 7XP
Vergences
D: 3/11/4 BI, 7/17/8 BO
N: 15/23/15 BI, 15/19/10 BO
AC/A=PD+WD(Pn-Pd)
5.8+.4(-7-(-3))=4.2/1
which of the follow values is used to determine whether this patient has sufficient vergences to compensate for her near phoria?
Habitual
OD: -4.00 -2.00 x 180 20/20
OS: -4.75 -3.00 x 180 20/20
CT
D: small XP
N: mod XP
VonGaefe
D: 3XP
N: 7XP
Vergences
D: 3/11/4 BI, 7/17/8 BO
N: 15/23/15 BI, 15/19/10 BO
BO blur at near
average amp of accommodation based on age 29
- 5-0.30(age)
9. 80D
gradient AC/A
determined by measuring the patients phoria at the same distance but with different lenses to change the stimulus to accommodate. Most often the phoria is measured at 40cm, first through the subjective refraction and then with +1.00D over the subjective refraction
can be calculated with
AC/A=(P1-P2)/(Sa1-Sa2)
Sheard’s Criterion
a patient will have comfortable, single binocular vision when the compensation mergence is at least double the phoria demand.
PFV compensates for a
XP
tested directly with BO prism or indirectly with plus lenses
what value of vergences represents the limit go PFV
blur value
-needs to be twice the phoria
NFV
compensates for an EP and is measured directly by adding BI prism or indirectly by adding minus lenses
what on vergences will suggest someone if over minused in their glasses
low BI blur value
symptoms of being over minused
asthenia when reading at night
-constantly accommodating at distance and near, resulting in the most symptoms at near when she has a higher accommodative demand
blur
the limit of fusional vergence; at this point, the patient will begin to use accommodative mergence to prevent diplopia. the image will appear blurred bc the patient is accommodating the change vergence, even though the target distance has not changed
break
the limit of fusional AND accommodative vergence. The patient has maximally relaxed or stimulated accommodation and can no longer change mergence, resulting in a blurred double image
recovery
a qualitative assessment of flexibility of the binocular system to regain fusion after diplopia (recorded when the image becomes single again). The recovery should be at least half the break
NRA in someone who is overminused
will be high (>+2.50) because the patient will relax 2.50D of accommodation for the near target at 40cm, plus the additional amount of accommodation he was using to clear objects through the extra minus lenses
accommodative facility in someone over minused
slow clearing of minus lenses, as the patient will already be over accommodating through her over minused RX. This finding will occur with monocular AND binocular testing. The patient will NOT have difficulty clearing plus lenses monocularly or binocularly
accommodative facility
determine the dynamic accommodative ability of the patient. The patient is asked to clear an image at near with a +/-2.00D lenses. the number of cycles (clearing plus and minus lenses) in one minute is recorded.
norms for accommodative facility
13-30yo
monocularly=11cpm
binocularly=8cpm
if a patient cannot clear plus AND minus lenses on accommodative facility
he has accommodative facility issues
if the patient cannot clear plus lenses, he is
over accommodating for the stimulus
if the patient cannot clear minus lenses, he has
decreased ability to accommodate (accommodative insufficiency)
push up test for over minused
will show a low amp of accommodation because some of the patients accommodative ability is being used for distance
push up test
measures the amp of accommodation. under monocular conditions, a near target is brought towards a patient until he no longer can read the image. The distance is recorded in cm. the amp of accommodation is the inverse of this distance
