David B. Granet, M.D. MHCM FACS FAAP is the Anne F. Ratner Professor of Ophthalmology & Pediatrics
at the University of California, San Diego where he is the Director of the Ratner Children’s Eye Center at
the Shiley Eye Institute. A graduate of Yale University School of Medicine where he served as a Class
President, he is the author of over 140 articles and book chapters, the founder of the International
Pediatric-Ophthalmology Internet discussion group, a past Chair of the Section on Ophthalmology for
the American Academy of Pediatrics and co-editor of their book on Ophthalmology for the Pediatrician.
He received the Innovation Prize from the Swiss Academy of Ophthalmology for the work he did with
Ken Nischal together founding the World Society of Paediatric Ophthalmology & Strabismus (WSPOS)
which they co-direct. Dr. Granet has received the Lifetime Achievement Award from the American
Association of Pediatric Ophthalmology and Strabismus (AAPOS) and has been voted perennially by his
peers into US News Best Doctors of America. In 2019 he was named on The Ophthalmologist’s “Top 50
Power List” as a Champion of Change and also this year graduated from Harvard University with a
Master’s degree in Health Care Management. In addition, Dr. Granet serves as the host for the award winning medical television show “Health Matters”.

1) How would you help this patient?
Decision on the intervention to help this patient depends upon analysis of his eye movements and his sensory system. Additionally, the goals of the patient help drive our decision making. The patient has a small angle exotropia (although in the cardinal gaze photographs looks good in primary position) and we are not told of an adopted head position, so will assume for these purposes there is none. However, when testing acuity for example, it is important to allow the patient to binocularly adopt the position they prefer, informing the physician to both the best acuity and if an abnormal head position is present. Without further information we are left to identify whether this represents fusion maldevelopment nystagmus (FMN) or infantile nystagmus syndrome (INS). On testing the waveforms are inverse of one another with either decreasing (FMN) or increasing (INS) slow wave velocity. Both can be improved with fusion and INS is greatly impacted by convergence. If there were a head position that would also impact the surgical decision. Finally, we have the patient’s stated goal of a high visibility job, reading a teleprompter, the lights of a studio (with albinism) and the relationship of the camera to teleprompter to patient for alignment appearance. I should also note that despite the high refractive error I’d consider toric contact lenses for the nystagmus damping that has reported from contacts and also for the tint that can be added to decrease glare in the studio. It should be noted that wearing glasses on television can decrease/hide the appearance of this patients eyes along with polarization and anti-glare additionally helping. One additional thought, in our experience – mirroring the few reports in the literature – using a calcium channel blocker drop has also decreased nystagmus in about 2/3 patients.
Putting this all together I’d want to know if the patient can converge for fusion and damp his own nystagmus. If so, in office testing to determine how much of the XT should be corrected to leave some convergence would be needed. If not, I’d use in office testing for the patient to simulate the sensory fusion positive or problems that might occur post op. It is hard to tell but in the photographic montage the patient has a component of an “A” pattern and perhaps SO overaction of the left eye. In the video there appears to be some rotary nystagmus worse on right gaze. No information is provided about frustration or measurements related to these issues and no head tilt is reported (although in the video, assuming the shades are level in the background, it implies a right head tilt). In some patients these issues can and do affect planning.
There is a larger body of information related to the impact of tenotomy with replacement for INS but some for FMN and my personal experience confirms that. Thus, with the information provided and assuming likely INS, I would perform a 4-muscle horizontal tenotomy and again assuming convergence does not provide fusion and damping of nystagmus, I would have recessed the right lateral rectus. If there were a mild head tilt, I would offset the horizontals by raising the right sided and lowering the left sided muscle of each eye. I would use an adjustable suture on the recessed muscle.

2) What do you feel is the most accepted theory for the mechanism of strabismus surgery dampening nystagmus?
The work by Dell’Osso and Hertle in specific has been seminal in the advancing our understanding of the failure of the exquisitely tuned cross talk between the sensory and motor systems leading to nystagmus. Using eye movement recording and electrical engineering type circuitry the genesis of nystagmus can be elucidated and documented. It is via this process the idea that “sensory” or “motor” nystagmus terms are meaningless and should be avoided. In addition, the identification of ganglion cells at the enthesial tissue of the tendon scleral juncture added anatomic confirmation to our understanding.
Other confirming data includes a simple observation made in the 1950s by Anderson and repeated by almost everyone performing surgery for nystagmus. With no strabismus and a head turn when the various types of surgery for head position are performed, the patient is not only changed by an elimination of the head position but the characteristics of the nystagmus are also altered (increased foveation time and null zone for example). If the surgery were not a proprioceptive/neurologic one and only “orthopedic” in nature, those other changes would not occur.

3) What is your experience with this surgery of four muscle Tenotomy and reattachment to dampen nystagmus?
Having been trusted by many hundreds of patients with nystagmus to assist in their care our experience has been very positive. Recall that a patient with INS and no strabismus nor a head position represents a small (about 10%) of all patients with nystagmus. For a patient undergoing the eponymously named Anderson-Kestenbaum type procedures for a head turn they get both the orthopedic and the proprioceptive benefits of surgery. It is the straight eyed, straight headed patient that helps prove the point that the A-K procedure has 2 essential impacts.
When possible, we look for the opportunity to complete in one surgery the movement of the muscles for strabismus, head position and nystagmus damping. That means multi-planar surgery can be tackled in one setting. Although seemingly intimidating, approaching the patient in a systematic way and using some (gulp) math makes this approachable. Credit goes to Rich Hertle, MD for grouping the surgical approaches into 9 categories for ease of understanding and implementing. I will note I use offset of the horizontal muscles for tilts and chin up/down positions more than he reports. Those patients have horizontal nystagmus and my experience supports this approach for those patients with smaller AHP’s.

4) What improvements does the patient clinically describe after surgery?
Although many patients report “seeing” better the improvement on Snellen type charts is limited. So why the disconnect? Black letters on a white background (high contrast), with no motion in a lighting-controlled room with the patient seated still, represents a small part of our visual world. Dynamic acuity (a greater range of improved foveation and a larger null zone) means the patient can navigate the world better, essentially getting more information per unit time. It can almost be thought of as “seeing faster”; they can identify items in a shorter period time. Do not be disappointed with no or little improvement in tested acuity as almost every other visual function improves, especially in a patient who gets some form of fusion. Moreover, none of us would want to ever give up a line of vision, thus we should respect the importance of its gain.
Perhaps my favorite moments are when a young pre-verbal child changes behavior almost suddenly post operatively. Some get up and walk when parents had feared they were delayed, some recognize objects or people better etc. Those children are not impacted by a placebo effect from surgery!
With regards to the possibility of such an effect, for those that have eye-movement recording pre and post op these changes are objectively noted. Similarly, dynamic acuity, contrast and more can be documented to improve. Those caring for large numbers of patients with nystagmus should have eye-movement recordings the same way we expect an EKG from a cardiologist.
Returning to our patient I’d still consider tinted contact lenses (even if they can’t fully correct his astigmatism) for improvement and the additional possible nystagmus damping. We have some patients that have undergone refractive surgery to reduce the Rx and then added contacts. Having a full armamentarium of options at your disposal means the patient gets the best outcome. His surgeons appear to have performed the football (soccer) equivalent of a clean-sheet while scoring several goals themselves!