Eugene M. Helveston

Retinoblastoma: One World, One Vision

Retinoblastoma is curable when diagnosed early and treated appropriately; however, the prognosis is dismal when the basic elements of diagnosis and treatment are lacking. In developing countries, poor education, lower socioeconomic conditions, and inefficient health care systems result in delayed diagnosis and suboptimal care. Furthermore, the complexity of multidisciplinary care required is seldom possible. Whereas ocular salvage is a priority in the Western world, death from retinoblastoma is still a major problem in developing countries. To bring the 2 ends of this spectrum together and provide a forum for discussion, the “One World, One Vision” symposium was organized, at which clinicians and researchers from various cultural, geographic, and socioeconomic backgrounds converged to discuss their experiences. Strategies for early diagnosis in developing countries were discussed. Elements of the development of retinoblastoma centers in developing countries were discussed, and examples of successful programs were highlighted. An important component in this process is twinning between centers in developing countries and mentor institutions in high-income countries. Global initiatives by nongovernmental organizations such as the International Network for Cancer Treatment and Research, Orbis International, and the International Agency for Prevention of Blindness were presented. Treatment of retinoblastoma in developing countries remains a challenge; however, it is possible to coordinate efforts at multiple levels, including public administrations and nonprofit organizations, to improve the diagnosis and treatment of retinoblastoma and to improve the outcome for these children.

The Trochlea: A Study of the Anatomy and Physiology

Trochleas obtained from fresh surgical specimens, autopsy material, and cadavers were studied by means of dissection, light microscopy, and electron microscopy (scanning and transmission). A bursa-like structure that has not previously been described lines the inner surface of the cartilagenous trochlea. A fibrillar, vascular sheath surrounds the intratrochlear superior oblique tendon. This portion of the superior oblique tendon consists of discrete fibers with few, interfibrillar connections. Each superior oblique tendon fiber is thought to move through the trochlea by means of a sliding action with the central fibers undergoing the maximum excursion.

Incidence of strabismus in neonates

In an attempt to learn whether esotropia is present at birth or develops later in infancy, we observed 1,219 alert infants in a normal newborn nursery at a city hospital. Of these, 593 (48.6%) had orthotropic findings; 398 (32.7%) had exotropia, 40 (3.2%) had esotropia (intermittent in 17 with 14 varying between esotropia and exotropia and nine with a variable esotropia), and 188 (15.4%) were not sufficiently alert to permit classification. No infant displayed typical signs of congenital esotropia. We concluded that congenital-infantile esotropia is not connatal but rather develops in the first few weeks or months after birth.

Large Recession of the Horizontal Recti for Treatment of Nystagmus

Ten patients had large recession of four horizontal recti at one procedure for treatment of nystagmus. Six patients had congenital motor nystagmus, two had oculocutaneous albinism, and two had optic nerve hypoplasia. Anomalous head posture with null point was also present in five patients. The rectus muscles were placed at or behind the equator in all but one case. Three patients with both esotropia and nystagmus had the medial recti placed 1 mm behind the equator and the lateral recti or at 1 mm anterior to the equator. Visual acuity improved an average of 1 line at distance and/or near in 8 patients who cooperated for testing. Although nystagmus was not eliminated in any patient, its its amplitude decreased in eight of ten patients, and anomalous head posture improved in three of five patients. In all patients, near vision was better than distance vision both preoperatively and postoperatively. Ductions were diminished minimally after the large recession and there were no other complications from surgery.

Treatment of Acquired Nystagmus with Botulinum A Toxin

We injected botulinum A toxin into the retrobulbar space of one eye each in two patients who had acquired nystagmus with oscillopsia and decreased vision. After injection of 25 units of botulinum A toxin, visual acuity improved from 20/80 to 20/30 in one patient, and both patients were able to read and watch television. Improved vision lasted from five to 13 weeks. No adverse side effects were observed after a total of five injections in each patient.

A new classification of superior oblique palsy based on congenital variations in the tendon.

BACKGROUND Superior oblique palsy is the most frequent isolated cranial nerve palsy seen in strabismus practice. It is traditionally diagnosed according to etiology as acquired, congenital, or idiopathic, but surgical treatment is based on deviation not etiology. Observations at surgery led to speculation that the superior oblique tendon is different in congenital compared with acquired superior oblique palsy and that this difference should be considered in surgical treatment. METHODS The authors reviewed the charts of 82 patients (89 eyes) undergoing surgery on the superior oblique tendon for superior oblique palsy. In each case, the palsy had been diagnosed preoperatively as acquired, congenital, or idiopathic, and, at surgery, characteristics of the tendon anatomy were described. RESULTS Thirty-eight superior oblique tendons (36 patients), diagnosed as congenital superior oblique palsy, included 33 abnormal tendons and 5 normal tendons. Twenty-four tendons (21 patients), diagnosed as traumatic superior oblique palsy, included 22 normal and 2 abnormal tendons. Twenty-seven tendons (25 patients), diagnosed as idiopathic, included 19 normal and 8 abnormal tendons. Abnormal tendons were divided into 4 categories: (1) redundant, (2) misdirected, (3) inserted in posterior Tenons capsule, and (4) absent. CONCLUSIONS The authors conclude that congenital superior oblique palsy is usually associated with a structural abnormality of the superior oblique tendon (87%). Whereas acquired superior oblique palsy usually has a normal tendon (92%). Superior oblique underaction in acquired superior oblique palsy results from a neural deficit. Potential variance in anatomy of the superior oblique tendon should be considered when undertaking surgery for superior oblique palsy.

Persistent Binocular Diplopia After Cataract Surgery

We reviewed the records of 38 consecutive patients who had persistent binocular diplopia after cataract surgery. The patients were divided into ten categories based on the suspected conditions underlying the diplopia. Of 16 patients who underwent strabismus surgery, five achieved the therapeutic goal of single binocular vision in the primary and reading position, and four attained this with prismatic or botulinum toxin therapy in addition to surgery. Seven patients continued to have diplopia despite strabismus surgery and adjunctive therapy. Even small residual deviations were often intolerable, because of highly diminished fusional amplitudes.

Surgical Treatment of Congenital Esotropia

We conducted a retrospective study of 133 children (69 boys and 64 girls) who underwent bilateral medial rectus muscle recession (most by the augmented or en-bloc technique) for congenital esotropia. Esotropia was diagnosed before the age of 6 months in 84 patients and after the age of 6 months in the other 49. A total of 27 children underwent surgery before the age of 12 months; of these, three required second procedures. A total of 106 children underwent surgery after the age of 12 months; of these, eight required second procedures. The mean preoperative deviation was 40 prism diopters. Two patients had significant A pattern deviations and 17 had significant V pattern deviations. Six patients had dissociated vertical deviations. Five to 60 days after surgery, 52 patients had no deviation and 99 were within +/- 10 prism diopters of no deviation. Two months after surgery, 67 patients had no deviation and 114 were within +/- 10 prism diopters of no deviation. Final alignments (five months to seven years postoperatively) showed that 51 patients had no deviation and 109 were within +/- 10 prism diopters of no deviation. Despite adequate alignment, none of 13 patients whose esotropia was diagnosed before the age of 6 months, who underwent surgery before the age of 12 months, and who cooperated with testing achieved stereopsis. This suggested that there may be two types of congenital esotropia--one without fusion potential and one in which fusion is possible but lost secondarily because of peripheral esotropic factors.

Congenital blepharoptosis, anisometropia, and amblyopia.

A review of the records of 65 patients who had surgery for congenital blepharoptosis of the upper eyelid during a three-year period revealed the preoperative presence of anisometropia, strabismus, or amblyopia in 19 patients. Postoperatively, ten of the 65 patients developed or increased their astigmatism in the operated eye. In four of these patients amblyopia attributed to this postoperative astigmatism developed. The results of our study suggest that blepharoptosis surgery done in the first few years of life may contribute to the development of astigmatism and amblyopia in some patients.

Progressive overcorrection after inferior rectus recession.

We reviewed 67 cases of inferior rectus muscle recession. In 14 cases, the hypotropia was corrected to a satisfactory alignment in the immediate postoperative period followed by a progressive overcorrection (hypertropia). Patients with thyroid eye disease were at highest risk for progressive overcorrection, as 9 of 18 (50%) developed the problem. Patients undergoing adjustable suture were at a higher risk for development of the overcorrection, as 1 of 35 (3%) surgeries done with standard techniques had the overcorrection while 13 of 32 (41%) done on an adjustable suture had the problem. However, the actual act of adjustment was found not to be a predisposing factor. Also, operating upon multiple muscles was found not to be a risk factor for the complication. Once progressive overcorrection occurred, it was more difficult to correct when the patient had thyroid eye disease. We also reviewed 77 consecutive cases of superior, lateral, and medial rectus muscle recessions and found no cases of progressive overcorrection.