The cover story in this issue of Ocular Surgery News is a round table chaired by our section leader in pediatric ophthalmology, Robert S. Gold, MD. The round table took place at the American Association for Pediatric Ophthalmology and Strabismus meeting in New Orleans in March. All of the round table participants are members of AAPOS.
When I finished my training in 1978, I first joined a group in Dallas whose senior partner, William S. Harris, MD, was primarily an anterior segment surgeon. I was told by my senior partner that it was the “duty” of the youngest associate to take care of strabismus and oculoplastics. I also cared for a lot of adults with cataract, corneal and glaucoma problems, but my experience was similar to that of many young surgeons starting out in private practice at that time: The strabismus and oculoplastic cases were all referred to me. Fortunately, my training in both disciplines was strong, and I was fairly comfortable with most cases I encountered.
Today, AAPOS numbers 842 active members along with 268 international members, 37 associate members, 99 orthoptists, 82 emeritus members and 147 candidates in training. Most pediatric patients, especially in large cities such as Minneapolis-St. Paul, today see a pediatric ophthalmologist. Frank Costenbader, MD, is generally credited as the founder of the pediatric ophthalmology specialty in the United States. His first fellow in Washington, D.C., was Marshall Parks, MD, who trained my residency mentor at the University of Minnesota, Robert Letson, MD. Today, the pediatric ophthalmology service at the University of Minnesota includes four full-time faculty, and there are another half dozen excellent private practice pediatric ophthalmologists in our community. Our group does some pediatric corneal, cataract and glaucoma surgery, but in most cases, one of the community pediatric ophthalmologists is also engaged in the care. We do no strabismus surgery. Thus, a patient with esotropia and a high accommodative amplitude would in nearly all cases see a pediatric ophthalmologist for surgery in our city.
Esotropia can be primary, secondary or consecutive after prior surgery. It can be comitant or incomitant — for example, when there is a muscle paresis as in a sixth nerve palsy. It can also be constant or intermittent. Another subgroup is accommodative esotropia. These patients are often hyperopic, but not always. The accommodative convergence/accommodation (AC/A) ratio is the prism diopters of convergence divided by the diopters of accommodation. It can be measured using the gradient method at a single distance using plus and minus lenses to stimulate accommodation, much as in a defocus curve. Most ophthalmologists simply measure the prism diopters of esotropia at distance while wearing best spectacle correction and then again at near. While definitions can vary, if there is more than a 10 D difference with the deviation being larger at near, the patient has a high AC/A ratio. Of course, the yang is accommodative insufficiency with a low AC/A ratio.
Treatment can be optical with full correction of any hyperopia and astigmatism. In some cases, a bifocal is prescribed. Anticholinesterase inhibitors such as echothiophate iodide help in some patients. In addition, any amblyopia is treated with patching or penalization. Many patients require surgery. In my training, a bilateral symmetrical medial rectus recession was the standard, but as noted in this round table, a medial rectus recession combined with a lateral rectus resection or plication is also being used by those expert in the field.
The amount of surgery planned depends on the prism diopters of esotropia. I still remember my training, which was 1 mm of medial rectus recession for every 3 D of deviation. Unfortunately, in patients with a high AC/A, the deviation measured at distance and near is significantly different. So, which should be used to plan the surgery? I was taught to split the difference, but some of our experts hedge toward undercorrection using the distance deviation, and some treat the full near deviation. A consecutive exotropia is possible for the aggressive surgeon, but in hyperopic patients, it can often be mitigated by undercorrecting the refractive error.
Plication is a less invasive alternative to a muscle resection, requiring no muscle removal. I personally have never performed a plication and found Dr. Wilson’s finding that the muscle seemed to reorient to a normal anatomy after a period of time quite fascinating. The ability of the young body to heal and restructure is amazing and well documented by our orthopedic colleagues.
Writing this commentary reminded me how different the practice of ophthalmology in the United States is today vs. 40 years ago when I started. We are definitely in the era of the subspecialist. Fortunately for the pediatric patient, and for my young associate anterior segment surgeons and me, there are many well-trained pediatric ophthalmologists to care for their needs.