Edward L. Raab

Succinyldicholine-induced Return of the Eyes to the Basic Deviation: A Motion picture Study

Succinyldicholine 2 mg/kg body weight returned the eyes of 20 anesthetized subjects to the same basic horizontal position as when conscious. The distance between the two eyes, as measured from motion pictures, agreed when the patient was in the conscious state and succinyldicholine-stimulated unconscious state by 99 +/- 10%. Since succinyldicholine has been shown by others to selectively produce a sustained contraction of en grappe muscle fibers, these muscle fibers are implicated as determinants of the basic ocular position and a cause of strabismus.

DVD--a conceptual, clinical, and surgical overview.

Dissociated vertical deviation (DVD) is a slow, disconjugate hypertropic deviation of a nonfixating eye. It is usually bilateral, asymmetrical, and often associated with congenital esotropia. The deviating eye elevates, abducts, and excyclotorts. This type of strabismus is often variable, making measurement and clinical quantification difficult. Specific knowledge of the mechanisms and characteristics of the dissociated deviation are required for proper assessment and effective treatment. There is currently no consensus on the mechanisms and pathophysiology of DVD. In this workshop, participants discuss the characteristics and most current methods for assessing and quantifying the deviation and explore the potential etiologies, clinical characteristics, and indications for surgical intervention and nonsurgical management of DVD.

Succinyldicholine and the Basic Ocular Deviation

We measured the ocular positions of conscious and anesthetized subjects from photographs. We obtained the conscious basic horizontal deviation by using the cover-uncover test. Intravenously administered succinyldicholine chloride, 2 mg/kg of body weight, returned the eyes of 15 anesthetized volunteers to positions that agreed well with those of their conscious horizontal basic deviations in the primary position. The mean ratio (+/- S.E.) calculated by dividing the horizontal interlimbal distance 90 seconds after drug injection by that of the same subjects horizontal interlimbal conscious basic deviation was 0.99 +/- 0.01. This result supported the theory that the multiply innervated (en grappe) extraocular muscle fibers were responsible for the basic deviation. Macaca nemestrina monkeys and baboons proved to be unsuitable primate models for the human succinyldicholine response. In humans, the drug-induced ocular position was often vertically above or below the primary position. The associated horizontal deviation appeared to follow the physiologic V pattern, being more divergent if the eyes were rotated up and more convergent if the eyes were rotated down. In one third of the subjects this vertical deviation resulted in drug-induced horizontal interlimbal distances that disagreed by more than 5% with those of the conscious basic deviation in the primary position. This effect makes succinyldicholine of little value for making quantitative estimates of the amount of ocular muscle surgery to be performed during strabismus correction procedures. We injected succinyldicholine at the conclusion of strabismus surgery in eight subjects to determine if the drug-induced ocular positions would predict the postoperative results. The muscles operated on responded as though temporarily paretic. The drug-induced ocular positions bore no resemblance to the postoperative results.

Questions Revisited: Is Experience Still the Best Teacher?

Introduction and Purpose To illustrate the value of experience in developing a simplified binocular sensory evaluation when required by necessity, and to describe the experience gained in repeating and extending a prior study. Patients and Method Prioritizing the information needed and the tests that provide it, and retrospectively reviewing a new population with similar inclusion and exclusion requirements, and dealing with the problem of uneven follow-up. Conclusion It is possible to derive a limited evaluation that is still sufficient for patient management. The prior results were confirmed and led to better understanding of the possibilities and limitations of retrospective studies.

Retinopathy associated with pancreatitis in a child with maple syrup urine disease

Editor,—Retinopathy associated with pancreatitis is an uncommon condition first described in 1975.1 To date, fewer than 50 cases have been reported, all involving adults. We report a case of pancreatitis with retinopathy in a young child with maple syrup urine disease, a rare metabolic disorder. A 7 year old Indian female presented with maple syrup urine disease (MSUD) diagnosed in infancy. She has been maintained on a special diet since then, enjoying normal development. However, during December 1995 she was admitted to the hospital for management of acute gastroenteritis and dehydration. Laboratory studies included serum amylase and lipase which were within normal limits. She received hyperalimentation with glucose and intralipids through a femoral catheter. On her third hospital day she was noted to have mental status changes which improved with hydration. However, on her sixth hospital day her mental status deteriorated again. Her abdomen became diffusely tender. Laboratory studies …

Accommodative ET-High AC/A Ratio Esotropia: The Case for Glasses.

Background and Purpose There is a continuing debate as to whether the patient optically correctable at distance to within 8 prism diopters of perfect alignment requires treatment for persisting overconvergence at near, and if treatment is indicated, what it should be. Patients and Methods For the patient whose misalignment at distance is reduced to 8 or fewer prism diopters, my preference is for the full cycloplegic correction plus a bifocal in the first prescription, to discourage virtually all accommodation initially, with pull back later. Results Review of several reports indicates a continued lack of consensus on whether this causes disuse weakening of accommodation and premature presbyopia. Recent studies found that prolonged convergence tone at near can result in anatomic and physiologic alterations in the medial rectus muscles that threaten a satisfactory distance alignment as well, despite relief of the accommodative demand. Hypoaccommodative esotropia resembles the high AC/A variety. Conclusion Spontaneously improving over-convergence at near is not likely to occur in the hypoaccommodating patient either with observation alone or with surgery. I reserve surgery for the over-convergence at near for the unusual case of an extremely high distance-near disparity, and for the teenager or adult not showing likelihood that the condition will resolve.

Lacrimal gland abscess in a child as a rare manifestation of IgG4-related disease

Dacryoadenitis is unusual in children, and noninfectious causes can be manifestations of serious undiagnosed systemic conditions. This report brings further attention to this rarely-encountered condition and emphasizes its association with IgG4-related disease, a group of inflammatory disorders of high current interest whose spectrum of manifestations continues to evolve. The pediatric ophthalmologist could be in the position of identifying a patients serious and previously unappreciated illness.

Historical Perspective of Surgical Approaches to Intermittent Exotropia

Introduction and Purpose To outline the progression of thinking about intermittent exotropia and its surgery. Patients and Methods Review of publications over a period of approximately 200 years. Results Revision of the concept that the cause of intermittent exotropia is excessive divergence to one recognizing that intermittent exotropia is a position of rest modified by convergence. Advances in technology have contributed to surgical approaches, especially for reoperations. Conclusion Most of our presently employed surgical procedures for intermittent exotropia are revivals rather than new, and have been adapted for deviations formerly considered too small for operation.

Importance of Birth Weight as a Risk Factor for Severe Retinopathy of Prematurity When Gestational Age Is 30 or More Weeks

PURPOSE To determine whether birth weight less than 1500 g is a relevant guideline indicating the need for examination for retinopathy of prematurity (ROP) when gestational age at birth is 30 or more completed weeks. DESIGN A retrospective observational cohort study. METHODS A total of 266 infants in a single institutional neonatal intensive care unit (NICU), whose gestational age at birth was 30 or more weeks but whose birth weight was less than 1500 g, were examined according to published guidelines. Infants with lethal congenital anomalies or major ocular abnormalities were excluded. Outcomes were vascularization in retinal zone III without a prior need for treatment, or ROP warranting treatment. RESULTS A study outcome was reached by 212 infants. Two hundred and eleven (99.5%) became vascularized through zone III without needing treatment. Only 1 (0.5%) required treatment for ROP. The 95% confidence interval for the occurrence rate of ROP requiring treatment in this cohort was 0.01%-2.60%. CONCLUSION Our results suggest that the occurrence rates of ROP requiring treatment in infants with gestational age 30 or more weeks and birth weight less than 1500 g is very low, and could indicate the need to revise examination guidelines for this subgroup of infants.