Henry S. Metz

Symposium on Strabismus

The Symposium on Strabismus contains the lectures and discussions of the 1977 New Orleans Academy of Ophthalmology meeting. The review of these transactions is similar to the old story that begins Theres good news and theres bad news. First, the good news. Many of the new techniques and approaches in strabismus are outlined. The section on adjustable sutures in strabismus is complete and well illustrated and reviews the rationale, as well as the various techniques available, for adjustment. Von Noordens discussion on amblyopia brings together some of the recent laboratory work with clinical implications. William Scotts chapter on saccadic velocity is succinct and practical. Excellent sections also include those on surgery of the superior oblique muscle by Helveston, complications of strabismus surgery by Mc Neer, surgical leashes by Jampolsky, lost muscles by Knapp, and adhesive strabismus by Reinecke. The chapter on surgery for Browns syndrome by Parks clearly outlines the

Horizontal saccadic velocities in Duane's syndrome.

Horizontal ocular saccadic velocities were measured by electro-oculography in 33 patients with Duanes syndrome. In 28 patients with limited abduction associated with retraction on adduction (Type 1), abduction saccadic velocity was markedly reduced while adduct-on saccades were moderately slow. In three patients with exotropia and good abduction but associated limited adduction and retraction on adduction (Type 2), abduction velocity was good, while adduction saccadic speed was slow. In two patients with limited abduction and adduction with retraction on adduction (Type 3), abduction and adduction saccadic velocity was appreciably slow. Ocular electromyographic testing selected patients indicated that slow abduction saccades could be explained by absence of lateral rectus muscle recruitment, while slow adduction saccadic speed could be explained by paradoxical innervation of the lateral rectus muscle.

Complications following surgery for thyroid ophthalmopathy.

A marked reaction postoperatively was noted following strabismus surgery for thyroid ophthalmopathy. Preoperatively, the right eye was noted to have a small amount of lower nasal conjunctival injection and chemosis while the left eye was quiet. Only the right eye had the severe inflammatory reaction postoperatively, while the left eye responded normally. The findings included marked proptosis, chemosis, subconjunctival hemorrhage, corneal exposure and drying with a sterile ring infiltrate, corneal thinning and vascularization, and ocular immobility. The treatment and course of these complications is described. It is suggested that muscle surgery be deferred in patients with thyroid ophthalmopathy when there are signs of continued inflammation.

Saccadic Velocity Measurements in Internuclear Ophthalmoplegia

Five patients with internuclear ophthalmoplegia had horizontal saccades measured by electro-oculography. In all patients, abduction saccadic velocities were normal while adduction saccades were slowed either binocularly or monocularly. In one patient, adduction saccades were reduced in velocity, even though full adduction was present. Saccadic velocity measurements may be helpful in diagnosing internuclear ophthalmoplegia, especially in the early or subclinical case. As bilateral internuclear ophthalmoplegia frequently suggests multiple sclerosis, prolonged examination with more sophisticated and difficult diagnostic tests is avoided.

Strabismus and Pseudostrabismus with Retrolental Fibroplasia

Three patients with temporal displacement of the macular secondary to retrolental fibroplasia had true strabismus in associations with amblyopia and pseudostrabismus related to a large, positive angle kappa. In one case, a headturn associated with the neutral point of nystagmus was also a presenting problem. Ocular deviation was measured by the light reflex test and the prism cover test, with particular attention paid to adequate cosmetic alignment. Large amounts of prism placed before the fixating eye resulted in loss of visual acuity, while eyes placed in a parallel position by surgical means may not appear to be straight. Thus, surgery can result in parallel ocular alignment while prismatic therapy may be required to center the pupillary light reflex and to provide satisfactory cosmetic appearance.

Alternate day esotropia.

A six-year-old girl was noted to develop alternate day esotropia three years following surgery for a moderate v esotropia. Many of the usual features of cyclic esotropia, including moderate hypermetropia, mild amblyopia, moderate to large deviation, a 48-hour cyclic pattern, and a high AC/C ratio were present. A therapeutic trial with strong miotics was unsuccessful. Saccadic velocity studies revealed no evidence of lateral rectus palsy. No fluctuations in pupillary size or response, refractive errors, accommodative amplitude, visual acuity, blood pressure, behavior, and the electroencephalographic pattern were noted. Following bimedial recession surgery, the eyes have remained straight and the cyclic pattern has been abolished for a two and one half year follow-up period. There is evidence to suggest that these patients are basically strabismic with cycles of remission.

Endocrine Ophthalmomyopathy in Adolescence

A 17-year-old girl presented with euthyroid Graves disease. Diplopia and extensive limitation of ocular motility bilaterally were the most remarkable features of this case. Even though the patient also had juvenile diabetes mellitus, treatment with systemic steroids was accomplished safely with complete recovery of ocular motility and the disappearance of diplopia in all fields of gaze.

Succinylcholine and Intraocular Pressure

Thirty-one patients (61 eyes) had a rise in intraocular pressure averaging 8.2 mm Hg following the use of succinylcholine as a muscle relaxant prior to general anesthesia. Just prior to the start of surgery (an average of 14 minutes following Anectine administration), the tension had returned to the control level. Ten patients (20 eyes) had pancuronium used without succinylcholine. No change in intraocular tension was noted with this agent and pressure remained unchanged at the start of surgery. Work of other investigators, using the spring back balance test and strain gauge force measurement to rotate the globe, indicate that the effect of Anectine upon the extraocular muscles may take 20 to 30 minutes to wear off. This is long after the return of intraocular pressure to control values and suggests that monitoring of intraocular tension may not be accurate method of assessing the action of Anectine upon the eye muscles. The mechanism of increased fluid outflow, not muscle relaxation, probably accounts for this lowering of intraocular pressure.

Rectus Muscle Transposition Surgery

Thirty patients had vertical offsets of their horizontal rectus insertions to correct a coexisting vertical deviation while 14 patients had horizontal offsets of their vertical recti to correct a horizontal deviation (total of 44 patients). The average effect of surgery was about 0.5 prism diopters per mm of surgery, both for a vertical or a horizontal effect. This is about half as much as generally reported in the literature, where one prism diopter of effect usually follows each mm of transposition. In our study, a greater effect per mm of surgery was noted with larger associated vertical deviations and larger amounts of vertical transposition of the horizontal rectus muscles.

Restrictions in the Diagnoses and Management of Strabismus Problems

Restrictions have been found to be a common cause of incomitant strabismus and limitation of ocular rotations. Different types of restrictions have been described and the technique of forced duction testing reviewed. Causes of restriction include endocrine eye disease, orbital floor and medical wall fracture, Browns syndrome, tight lateral rectus syndrome, congenital tight muscles, scarring, muscle contracture, and orbital celluitis or tumors. The importance of recognizing restrictions in the management of these problems has been emphasized.