- Approaching the Adult Patient with Strabismus
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When examining an adult patient with strabismus, think of the patient as a whole person, don't just concentrate on the eyes. Why is he/she coming to see you? What is happening in this patient's life to justify seeking your services? Trying to answer these and other similar questions, you should establish a relationship with the patient based on your perception of his/her unique needs and/or wishes. Remember, children with strabismus are a "captive audience"; they are brought to the ophthalmologist by a concerned parent or other adult who wants the child to see well and look normal. Think of the situation of the child in terms of the orthodontist. No kid ever sought these services on his/her own! Adults might seek the services of the orthodontist ,but only for special reasons - not unlike reasons employed in seeking out an ophthalmologist for treatment of strabismus, such as:
I. Acute Double Vision
* After head trauma - VI N, IV N, III N palsy?
* Long standing strabismus - getting worse
* Acute strabismus with diabetes - other vascular cause?
* Myasthenia (variable strabismus with diplopia)
* Intracranial disease - tumor, aneurysm
* Was in a MVA or equivalent - tactfully determine if litigation is pending.
* Always ask, "Is double vision monocular?" If monocular, diplopia goes away looking through pinhole; suspect media defect - if not, suspect retinal defect.
II. Long Standing Strabismus
Many strabismic adults have had prior surgery and think nothing more can be done or they may have poor vision in one eye causing sensory strabismus and don't think the eye can or should be aligned. These patients usually have no visual complaints because of suppression, poor vision, or the fact that they are used to seeing the way they do. Before coming to see you, these patients must admit to themselves, and possibly others, that they don't like the way they look. This is a delicate matter - be diplomatic. Remember - "Every human has the right to look like a human." Humans have frontally aligned eyes. Attaining aligned eyes when looking straight ahead makes a human look better, that is, like a human; but surgery to accomplish this is not cosmetic per se!
These patients can be very challenging. T hey usually have a normal sensory state and may fuse to 40 sec. etc., but have deficient oculomotor resources to maintain alignment - with comfort - for sufficient periods to meet the particular patient's needs. With this type of patient it is essential to learn about any unique occupational or other visual requirements. Finding the right treatment can be a real challenge. These patients worry about lighting, computer use, etc., etc., etc.
IV. Diplopia after Cataract Surgery
This is a special category of patients. This clinical condition is becoming more common because of widespread and successful cataract surgery. These "old folks" obtain bright 20/20 vision in both eyes but may lack sufficient motor fusion to maintain single binocular vision. A more likely occurrence is that they have been the "victim" of an impaled - (injected)inferior rectus which is at first paretic and then fibrotic. These patients are relatively easy to fix and should be fixed right away, first with Fresnel prism which is preferable to a patch, and then with inferior rectus recession (or other appropriate muscle procedure). T his is ideally done with local anesthesia allowing for adjustment on the table.
* For purposes of this dicussion, the adult patient will be considered as anyone who has acquired strabismus after attaining "visual adulthood" at age 8 or 9 years or those who are seeking help after a lapse of many years from original treatment.
V. Other Considerations Regarding Strabismus in the Adult
The four categories of adult strabismus listed above contain a mixture of symptoms, signs, and etiologies, and beg the question, "How do you fix the problem?" The answer is: first, you understand the patient's special needs; second, you judiciously employ Fresnel prism in patients with diplopia (remember - you can rotate a Fresnel prism to create horizontal and vertical effect with a single prism); third, you carry out accepted surgical technique using adjustable sutures and local anesthesia when these techniques are feasible and when you believe they will increase the chances for a successful outcome. Adjustable sutures with adjustment "on the table" in an alert patient has the advantage of both ease and accuracy. In other cases, such as when general anesthesia is employed, a tandem adjustable suture offers the advantages of both a fixed (hang back) and a fully adjustable suture.
The Tandem Adjustable Suture for Recession
Step #1 Place a suture in your usual fashion for a recession (A) and then place a second suture immediately behind. (B)
Step #2 Detach the muscle
Step #3 A.Use suture A to do a "hang back" recession tying it securely at the muscle stump.
Step #4 Close the conjunctiva or recess the conjunctiva to the original insertion site. Bring the long ends of suture B out through the sides of the limbal incision exposed - suture B is tucked behind the lids.
Step #5 The next day if patient is satisfactorily aligned, cut off excess suture B and tuck it under conjunctiva. If the patient is over or under corrected, use suture B as an adjustable suture. In case of an under correction, it will be necessary to cut suture A. In an overcorrection just pull up on suture B. If a limbal incision is used the conjunctiva must be taken down and replaced. This technique can be modified for an adjustable resection.
Head tilt, chin up, chin down, etc. can be a sign of adult strabismus.
Any time an adult patient presents with acquired strabismus and without an obvious etiology the differential diagnosis should include appropriate consideration of the following:
* Thyroid ophthalmopathy
* Diabetic vasculopathy - stroke
* Multiple sclerosis (nystagmus - oscillopsia, internuclear ophthalmoplegia)
* Blowout fracture
* Decompensated congenital IV N palsy (head tilt - facial asymmetry)
* Convergence insufficiency
* Post retina or glaucoma surgery
There is lots more to be said about strabismus in the adult. The above is aimed at establishing a proper "mind set". Understanding the specific techniques for management of strabismus in the adult are also important and will be discussed later.
The Strabismus Minute, Vol.1, No. 11 Copyright (C) 1999 Eugene M. Helveston All Rights Reserved
Editor-in-Chief: Eugene M. Helveston, M.D.
Associate Editor: Faruk H. Orge, M.D.
Editorial Board: Bradley C. Black, M.D.
Edward O'Malley, M.D.
David A. Plager, M.D.
Derek T. Sprunger, M.D.
Daniel E. Neely, M.D.
Naval Sondhi, M.D.
Senior Editorial Consultant: Gunter K. von Noorden, M.D.
Graphics: Michelle L. Harmon
Technical Support: George J. Sheplock, M.D.