Nelson: Today we're going to discuss management of strabismus syndromes. The first patient has a type 1 Duane retraction syndrome of the left eye with a left face turn of approximately 15 degrees and an esotropia of 25 prism diopters (PD) in the primary position. The patient essentially has no abduction past the midline and the refraction is +1.00 diopters (D).
DeBenedictis: I don't believe glasses would help this patient. I would do a medial rectus recession of the left eye for 25 PD of esotropia.
Schnall: In Duane syndrome, the measurement of the deviation will be different depending on whether the prism is placed in front of the affected or the unaffected eye. The amount measured with the prism in front of the unaffected eye is usually more. I tend to base my surgery on the amount of deviation measured with the prism in front of the unaffected eye. Is the prism in front of the right or the left eye?
Nelson: The left eye.
Schnall: In my experience, 25 PD with the prism over the affected eye is large for a type 1 Duane retraction syndrome, but it does occur. I'd also look at the amount of limitation in adduction. If there's significant limitation of adduction, I would be more cautious in my medial rectus recession. I don't want to get synergistic divergence where the medial rectus ends up being weakened so much that the eye actually abducts on attempted adduction.
Nelson: Let's assume that the limitation is a moderate amount that is typical for Duane syndrome.
Schnall: I would recess the medial rectus muscle. If the measurement was similar in the right eye, I would recess approximately 6 mm.
Nelson: If the refraction was larger (eg, +2.00 or +3.00 D), would you give the glasses initially and reevaluate the patient or would you still do the surgery?
DeBenedictis: If it was larger than +1.50 or +2.00 D, I might have a discussion with the family about trying the glasses to see if there was any alleviation of the crossing, knowing it likely would not correct it.
Schnall: I would approach this similar to when we prescribe glasses for our patients with infantile esotropia. If the hyperopia is significant, I would prescribe the glasses. My threshold for prescribing glasses is +2.50 or +3.00 D. I would prescribe the glasses and see whether it changes the deviation significantly. For +3.00 D, I think the standard would be to prescribe the glasses first.
Nelson: The same patient whom you treated comes back 2 years later and now has redeveloped esotropia of 15 to 20 PD, has a 10-degree face turn, is able to abduct the eye just past midline, and has a minimal refraction. How would you manage this patient?
Schnall: In Duane syndrome, the best procedure for a patient with type 1 is recessing the medial rectus muscle in the affected eye.
Nelson: You would re-recess the muscle first.
Schnall: If there was enough room to re-recess it and there were no significant limitation of adduction, I would tend to re-recess it. Other options would be to recess the medial rectus muscle in the unaffected eye or a transposition procedure in the affected eye. I feel both of those procedures often don't work out as well as re-recession of the medial rectus in the affected eye.
DeBenedictis: I agree. For Duane syndrome, a recession would be my surgery of choice. Obviously, I wouldn't want to do any type of resection laterally because it's going to make the retraction worse and it won't help much. If there was enough room, I would do a re-recession of the medial rectus muscle. If that wasn't a great option or it didn't work, I would talk with the parents about operating on the unaffected eye and doing a recession in the opposite eye, but some parents are a little nervous about it.
Nelson: The next case is also Duane retraction syndrome in a 4-year-old child with a left face turn of approximately 15 degrees, esotropia in the primary position of 25 PD, and a significant leash effect upward on attempted adduction.
DeBenedictis: I would try a recession of the medial rectus muscle of the affected eye (in this case the left eye) and see how the patient responds. Sometimes just doing the recession can alleviate some of that leash effect and the tension from the co-contraction.
Schnall: The leash effect occurs because the horizontal rectus muscle slides underneath the eye or the eye jumps above the muscle. Either weakening the muscle with recession or stabilizing the horizontal muscle by a Y split or a Faden suture can help to prevent the slippage from occurring. The procedures to treat a leash effect are usually described on the lateral rectus muscle because the leash effect usually occurs in type 2 and type 3 in attempted adduction. In my experience, an upshoot in type 1 is rare. For a patient with type 1, I would tend to treat it similarly as with type 2, by just recessing the medial rectus and not making a Y split. If there was a lot of co-contraction and the eye appeared enophthalmic, I would think maybe this is not a type 1 but a type 3 and consider recessing both the medial and the lateral rectus muscle.
Nelson: The next case is type 2 Duane syndrome of the left eye with a right face turn of 25 degrees, an exotropia of 20 PD in the primary position, and no adduction past the midline.
Schnall: In Duane syndrome, we're better off recessing than resecting and operating on the affected eye. I would recess the lateral rectus muscle on the affected eye. For the 20 PD, it depends on whether I measure a +1.00 D in the affected eye or the unaffected eye. I would probably do an 8-mm recession of the lateral rectus muscle.
DeBenedictis: My primary approach would be to recess the lateral rectus muscle in the affected eye for the exotropia.
Nelson: Do you think the adduction improves when you recess the lateral rectus?
Schnall: No. My experience is that, whether it's an abduction or adduction deficit in Duane syndrome, you're not really improving the duction significantly with strabismus surgery.
DeBenedictis: I wouldn't expect a significant improvement in function.
Nelson: The next case is a 4-year-old girl who has an esotropia for several years of approximately 35 PD with a cycloplegic refraction of +0.50 D. The parents say they're not sure that the esotropia is always there. How would you handle this patient?
DeBenedictis: My approach for these patients is always the same. I do a full dilated examination, assuming that the anterior and posterior results are normal, the patient has full cycloplegic refraction, and I don't suspect that there's any other covered hyperopia that I can't see. I ask about family history and the onset because it's either a congenital esotropia or a non-accommodative acquired esotropia. This is a significant esotropia that's going to affect the development of three-dimensional vision, so I would likely do a bilateral medial rectus recession for 35.00 D.
Nelson: What if the parents say some days the eye looks like it's crossed and other days it looks straight? They show you a picture from a week ago and her eyes look perfectly straight.
DeBenedictis: I would consider whether there is any pattern or cyclical component to the eye crossing.
Nelson: The parents are just not sure. They never kept a record of it.
DeBenedictis: I would bring this patient back in a few weeks. I would ask the parents to start tracking it and show them what to look for. We also want to make sure that it's not crossing more up close versus far away, which can sometimes throw people off.
Nelson: Let's say they come back in 3 weeks. They still are not sure and the child's eyes are perfectly straight.
DeBenedictis: I'd likely continue to follow the patient to try to get more information. Does it happen more when the child is tired or ill? Is it affecting the child's visual development?
Schnall: The history you describe is typical for cyclical esotropia. The measurement of the esotropia on the days the eyes are crossed tends to be consistent with little variability. If you do strabismus surgery, they do not alternate after surgery. They're straight every day and they tend to get a good result with good binocular vision after surgery. I think Dr. DeBenedicitis's initial impression of doing a bilateral medial rectus recession on this patient is exactly what is needed.
Nelson: Does it make a difference to you that the eyes are straight on the day of surgery?
Schnall: No. You have to be braver to operate when the eyes are straight the day of surgery, but the patients do well with strabismus surgery and the parents know the eyes turn in. I've never had a parent not want surgery because the eyes were straight on the day of surgery. This is an uncommon entity, but it does occur.
Nelson: The next patient is a 4-year-old boy who has a right face turn of 10 degrees in primary position and a left hypotropia of 10 PD. He is unable to elevate his left eye in the adducting position, but the elevation improves in the straight up and abducting positions. The patient has Brown syndrome of the left eye. How would you manage this patient?
DeBenedictis: How large is the hypotropia in primary position?
Nelson: It's 10 PD. The vision is normal. He just walks around with a face turn.
DeBenedictis: Most of the Brown syndromes that I see are fairly mild and I know that historically the surgery for Brown syndrome can be hit or miss. The patient has a small head position without obvious amblyopia. I want to know whether the head position and vision development are abnormal enough to warrant surgery on the superior oblique muscle. I might recommend close observation because it sounds like he's able to align the eyes with a small head position so that his vision is developing normally.
Nelson: Let's assume the patient comes back in 3 months and still has the same clinical scenario. The parents say he is starting to get teased about the way he looks with his face.
DeBenedictis: If there are vision development issues or if the head position is causing a significant issue, I would consider a spacer for the superior oblique to try to increase mobility.
Schnall: In Brown syndrome you need to know whether it's acquired or congenital. Acquired Brown syndrome will often resolve. Congenital can resolve, but it's less common. If it is the acquired type, I would watch it. If it is congenital, I would consider strabismus surgery.
With all types of incomitant strabismus, our indications for surgery are the same—a significant deviation in primary position or if the patient has a head posture. In this case, there is a head posture that is not going away and it's not an acquired Brown syndrome. I would do a weakening procedure on the superior oblique, whether that's a tenotomy or by lengthening the tendon with a spacer. When you lengthen the tendon, you risk causing a superior oblique palsy because usually these patients do not have superior oblique overaction.
Nelson: Would you tell the patient there's a chance that he may develop an inferior oblique overaction?
Schnall: In my experience, it tends to occur more with mild Brown syndrome than severe cases. I think you should warn the parents and patient that a second procedure could be needed.
Nelson: The last case is congenital fibrosis in a 5-year-old girl. The visual acuity is 20/25 in each eye. She maintains a chin-up position of approximately 25 degrees and has minimal ability to elevate either eye, even to the midline. The patient is orthophoric, but only as measured in down gaze. How would you handle this patient?
Schnall: This patient you're describing has limited ability to elevate both eyes and it's a similar position. There is no hypertropia, one eye relative to the other?
Schnall: I always start with a forced duction test. If she has difficulty elevating the eyes, then surgery is indicated. We need to do something to help with the chin-down position. If the forced ductions are positive I would perform a large weakening procedure for the inferior rectus, either a large recession or a tenotomy of the inferior recti.
Nelson: How would you determine whether you would do a tenotomy or a large recession?
Schnall: I'm not sure I have a good answer to that. I tend to do a large hang-back suture rather than a free tenotomy. I would recess the muscle 8 to 10 mm per eye. If the patient was undercorrected, then I would do a tenotomy.
Nelson: Thank you for your insights.
This Eye to Eye session was conducted on March 11, 2019.