Nystagmus III Flashcards
Goal of nystagmus management
Improve
- VA
- ocular motor control
- binocularity
- cosmesis
- comfort
Things to do for nystagmus management
- glasses or contacts for refractive error
- prisms to improve fusion, induce convergence, reduce head turn
- yoke head turn to move the null point
- vision therapy to improve fusio nand fixation
- surgery for severely head positioning
- medication
Why do we use prism for nystagmus
Improve fusion
Induce convergence
Reduce head turn
Why refractive correction for nystagmus
To improve the clarity of the retinal image to maintain steady fixation, to lessen the nystagmus
What’s the first things to take care of when treating nystgmus or anything else
The offending problem, such as ptosis
Nystagmus correction for hyperopia
1-2D
Nystagmus astigmatism correction
0.50D or more
Rx ____ for myopia in nystagmus
0.50D or more
Can they wear contacts in nystagmus
Yes, RGP and soft lenses
Plus adds for nystagmus
Valuable at near for improved Va and clarity for near point demands, aid in accommodation at near
Minus adds in nystagmus
Some clinicians may try minus to induce convergence since nystagmus could decrease with convergence
-before doing this make sure it will not interfere with binocularly and make the nystagmus worse
Don’t overminus
Prism in nystagmus
- improve binocularity and reduce nystagmus intensity
- maybe serve to improve strabismus
May also be used for
-induce convergence or move null point
Prisms to induce convergence
Use a small amount of BO prism (induces convergences). This stimulates fusional convergence to dampen nystagmus
The amount required varies
Prism for anomalous head position
Yoked prisms can also be used to improve VA and slow down the nuystagmus by improving abnormal head postures
How is the prism placed for anomalous head position
Base is places in the same direction as the head turn-this keeps the patients eyes in the eccentric null position while lessening the head turn
Why do we give BO for inducing convergence
Give BO for an ET, if you over do it, you will get a reversal and now the person becalmed XT, they will be able to converge to overcome this small amount
BO OD and BI OS will shift the image
To the left, improving visio nand improving a small right head/face turn
What kind of eye movement do we want to fix anomalous head position with prism
Version eye movement
The base Is the same way in both eyes
BO OD and BI OS will shift the image to the left, improving vision and improving a small right head/face turn
The use of yoked prism for shifting the null point
Yoked prism shifts the retinal image toward the null point
What type of prism should you use to move image to null point
If fresnel prisms are used for a large amount of prism, there is a degradation to the vision. Ground prism prevents distortion int he vision
Where is the apex of the prism placed in prism for null point
Towards the null point and base it towards the turn
If the patient has a left head turn, the patient has the null point in the right gaze, what kind of prism to use
Use base ego the left over each eye. This will shift the image to the right and reduce the head turn
Occlusion in nystagmus
Unfortunately, this will end to the latent components manifesting
Amblyopia treatment in these patients is difficult-may need to consider plus lenses over the better seeing eye (enough to blur but not enough to disrupt fusion)
VT for nystagmus
For fusional vergences or to improve motor control
And for suppression that could lead to manifest latent nystagmus
