NON-PRESBYOPE ACCOMMODATIVE DYSFUNCTIONS

 

I. DIAGNOSTIC USE OF PROBE LENSES

a. combines near point retinoscopy (MEM) with + spherical lenses.

b. measures "plus acceptance"

c. +1.00 O.U. is typically used. In this case, near point retinoscopy (MEM) is performed with the patient wearing +1.00 O.U. over the habitual correction or tentative Rx. The changes in accommodative responses to these lenses is evaluated and compared to MEM baseline results. MEM is performed in the usual way with trial lenses inserted for a brief time, such that accommodation doesn't change to these lenses.

d. Example 1 (40 cms; 2.50 D):

i. MEM = +0.50

(demand = 2.50 D; MEM = +0.50; patient's accommodation level = 2.00 D)

ii. MEM repeated with +1.00 O.U. = +0.50

(demand = 1.50 D; MEM = +0.50; patient's accommodation level = 1.00 D)

Interpretation:

"good plus acceptance", patient relaxed accommodation 1.00 diopter 

e. Example 2:

i. MEM = +0.50

(demand = 2.50 D; MEM = +0.50; patient's accommodation level = 2.00 D)

ii. MEM repeated with +1.00 O.U. = -0.50

(demand = 1.50 D; MEM = -0.50; patient's accommodation level = 2.00 D)

Interpretation:

"poor plus acceptance", patient did not relax any accommodation

ACCOMMODATIVE SYNDROMES

Several accommodative syndromes or response pattern emerge with clinical testing. They are based on the response properties of accommodation and the names are self-explanatory.

    a. accommodative insufficiency

    b. accommodative excess

    c. accommodative infacility

    d. ill-sustained accommodation

    e. inconsistency of accommodation

This table compares the accommodative syndromes across a number of commonly used clinical tests:

Syndrome Table
insufficiency
excess
infacility
ill-sustained
amplitude
reduced
normal
may be reduced
reduced
accuracy (MEM)
large lag
small + or - lag
small + or - lag
large lag
facility (+/- 2.00)
reduced -
reduced +
reduced + & -
reduced -
plus acceptance
very good
poor
poor
good
fused X-cylinder
more than expected
less than expected
less than expected
more than expected
near phoria
higher exo, esophoria
less exo
less exo
higher exo, esophoria
PRA / NRA
low PRA/normal NRA
normal PRA/low NRA
low PRA/low NRA
low PRA/normal NRA
NRC / PRC
consistent with PRA/NRA, phoria
consistent with PRA/NRA, phoria
consistent with PRA/NRA, phoria
consistent with PRA/NRA, phoria
fixation disparity
consistent with phoria
consistent with phoria
consistent with phoria
consistent with phoria
kinetic cover test
typically +
usually -
usually -
typically +
interactivity
consistent with phoria
consistent with phoria
consistent with phoria
consistent with phoria

MANAGEMENT OF ACCOMMODATIVE DISORDERS

 

I. TOOLS:

    a. Lenses

1. proper refractive correction is the first step in management

2. plus for near (add)

    b. Prisms?

    c. Vision therapy

    d. Combination of the above (a & c)

II. CONSIDERATIONS:

a. severity of condition. How far from the expecteds are clinical test results?

b. patient symptoms. Is the patient symptomatic?

c. level of impairment. How significantly has the accommodative dysfunction (BV) impacted on activities of daily living?

d. patient goals. Is patient interested in symptomatic relief primarily?

e. financial. Does the patient have financial or insurance limitations?

f. compliance risks. Is the patient a poor risk for completing a vision therapy program?

III. SPECIFIC DISORDERS:

    a. accommodative insufficiency

    1. plus for near

    2. vision therapy

    3. both

    b. accommodative excess

    1. vision therapy

    2. plus for near

    c. accommodative infacility

    1. vision therapy

    2. plus for near

    d. ill-sustained accommodation

    1. plus for near

    2. vision therapy

    3. both