Convergence Insufficiency/Divergence Insufficiency Convergence Excess/Divergence Excess: Some Facts and Fictions.

Great discrepancies are often encountered between the distance fixation and the near-fixation esodeviations and exodeviations. They are all attributed to either anomalies of the AC/A ratio or anomalies of the fusional convergence or divergence amplitudes. We report a case with pseudoconvergence insufficiency and another one with pseudoaccommodative convergence excess. In both cases, conv./div. excess and insufficiency were erroneously attributed to anomalies of the AC/A ratio or to anomalies of the fusional amplitudes. Our purpose is to show that numerous factors, other than anomalies in the AC/A ratio or anomalies in the fusional conv. or divergence amplitudes, can contaminate either the distance or the near deviations. This results in significant discrepancies between the distance and the near deviations despite a normal AC/A ratio and normal fusional amplitudes, leading to erroneous diagnoses and inappropriate treatment models.

Is Inferior Oblique Overaction Associated With Astigmatism?

PURPOSE: To study the relationship between inferior oblique muscle overaction and astigmatism, and to explore any change in astigmatism after surgery. METHODS: This was a retrospective chart review of patients undergoing strabismus surgery. Demographic data collected included age, diagnosis, preoperative refraction, presence of inferior oblique overaction, surgery performed, and postoperative refraction. Patients were divided into three groups: those having only horizontal strabismus without inferior oblique overaction (no inferior oblique group) as a control group, those having bilateral inferior oblique overaction (bilateral inferior oblique group), and those having unilateral inferior oblique overaction (unilateral inferior oblique group). Right eyes of the bilateral inferior oblique and no inferior oblique groups were chosen for analysis, whereas the eye with inferior oblique overaction was included in the unilateral cases. Refractions were converted to power vector coordinates for comparison. Statistical analysis was performed to compare the power vectors among groups using the no inferior oblique group as controls and to explore any postoperative change in astigmatism. RESULTS: One hundred eighteen patients undergoing strabismus surgery were included (60 males and 58 females; mean age: 11.31 ± 10.59 years). Patients were divided into three groups: those having only horizontal strabismus without inferior oblique overaction (no inferior oblique group; 60 patients) as controls, those having bilateral inferior oblique overaction (bilateral inferior oblique group; 41 patients), and those having unilateral inferior oblique overaction (unilateral inferior oblique group; 17 patients). Preoperatively, there were no differences in astigmatism when comparing eyes with and without inferior oblique overaction. Postoperatively, both the no inferior oblique group and the bilateral inferior oblique group equally showed an increase in with-the-rule cylinder power (P = .02 and .01, respectively). CONCLUSIONS: Inferior oblique muscle overaction did not result in an increased prevalence of astigmatism along the axis of the overacting muscle.

Major Review: Management of Strabismus Vertical Deviations, A- and V-Patterns and Cyclotropia Occurring after Horizontal Rectus Muscle Surgery with or without Oblique Muscle Surgery.

PURPOSE: To show conditions where a vertical deviation, an A- or a V-pattern or cyclotropia can appear after surgery on the horizontal rectus muscles, with or without oblique muscle surgery. Our purpose is also to show conditions when a vertical deviation can be anticipated before horizontal rectus muscle surgery and realignment of the ocular deviation. Finally, our purpose is to stress on some surgical precautions one should take to avoid such complications. CASE REPORTS: We report two cases who showed significant vertical deviations due to complications that followed surgical weakening procedures of the inferior oblique muscles. CONCLUSION: 1. Vertical deviations, A and V patterns and cyclotropia can occur, can be anticipated or can be avoided in pure horizontal rectus muscle surgeries 2. Vertical deviations are common following complicated oblique muscles surgery if the surgeon blindly sweeps the muscle hook into the area. They can be avoided if the weakening technique allows direct visualization of the inferior oblique muscle.

Review: oculomotor cranial nerve palsies: symptoms, problems and non-surgical preoperative management of the resultant complex incomitant strabismus and monocular and binocular vision disturbances.

The purpose of this presentation is first to describe the symptoms and problems encountered in cranial nerve palsies (CNP). The purpose is also to describe the different means of treatment during the observational preoperative period and their positive or negative impact on each of the symptoms and problems. Finally, we will present our way of handling these patients in their preoperative period: practical, inexpensive, and unsophisticated means that keep the patient comfortable and prevent the secondary untoward effects that can take place.

A review: the determination of visual acuity in infants and preliterate children.

In the field of pediatric ophthalmology, assessment of visual acuity is important and necessary in determining treatment plans for children with both functional as well as organic amblyopia, and also to monitor the effect and success of treatment.We shall review the qualitative/subjective tests, as well as the objective/quantitative tests described in the literature for assessing visual acuity, and we shall outline the complexity of vision and its impact on the objective tests.The main purpose of our paper is to present our own scheme of determining visual acuities in infants and pre-literate children, a scheme we believe is simple, effective, implies no extra costs, applicable to infants and young children, and almost infallible in detecting severe amblyopia.

Inferior oblique muscle palsy with "paradoxical" v-pattern strabismus.

BACKGROUND AND PURPOSE: A- and V-patterns are commonly encountered with cyclovertical muscle palsies. Inferior oblique (IO) muscle palsy produces and A-pattern caused mainly by the decreasing abducting action of the IO in upgaze and an increasing abduction action of the superior oblique in downgaze. V-pattern association with an IO palsy has not been, to our knowledge, reported before. The purpose of our paper is to report on a patient iwth IO palsy and a paradoxical V-pattern and explain the proposed pathophysiology behind the V-pattern. CASE REPORT: We report a 67 year old female with a 3 year history of diplopia. She met the Bielschowsky/Parks three step test to identify an IO muscle palsy, and she showed all the usual criteria of an IO muscle palsy except for a paradoxical V-pattern. CONCLUSION: Many forces affect patterns in cyclovertical muscle palsies. A V-pattern in IO palsy can be explained by the spread of comitance resulting in inhibitional innervational pseudo-palsy of the superior rectus muscle resulting in V-exotropia or in inhibitional palsy of the contralateral superior oblique muscle resulting in V-esotropia.

Abnormal binocular vision: monocular diplopia of physical origin: two case reports. Its relationship to the physiology and arrangement of the visual directions of the retinal areas; binocular triplopia.

BACKGROUND AND PURPOSE: Monocular diplopia is an infrequent but disabling complication following laser peripheral iridotomy, or following cataract surgery. Our purpose is to clarify the intraocular mechanism of monocular diplopia (and binocular triplopia) of physical origin and its relation to the physiology and arrangement of the visual directions of the retinal areas in each eye. CASE REPORTS: This is a report of one patient who developed monocular diplopia following an "exposed" laser peripheral iridotomy, and of a second patient who developed monocular diplopia due to a swollen opacified central posterior capsule following cataract surgery. CONCLUSION: Monocular diplopia of physical origin results from stimulation, by an object of regard, of two separate retinal areas that have two different visual directions due to optical ocular pathology.

Isolated inferior rectus paresis with falling eye phenomenon of the contralateral eye in a patient with pineal tumor: a case report.

UNLABELLED: PRUPOSE: To report a patient who developed an isolated inferior rectus paresis due to a pineal gland tumor, and to our knowledge never reported before. Our purpose is also to demonstrate that, even in partial and mild inferior rectus muscle paresis, the findings of the inhibitional palsy described by Chavasse and the downshoot of the fellow eye in adduction help determine the diagnosis. CASE REPORT: A patient with pineal gland tumor demonstrated findings characteristic of unilateral isolated inferior rectus paresis. CONCLUSION: Although bilateral sixth nerve paresis and Parinaud's syndrome are commonly reported in pineal gland tumors; in the the presence of an isolated inferior rectus palsy, one should also consider the pineal gland as the causative factor.

Partial third nerve palsy involving the superior rectus and levator palpebrae muscles and distruption of central binocular vision fusion from brain stem infarction: a case report.

BACKGROUND AND PURPOSE: To add to the literature of a case of isolated third nerve paresis involving the nerve fascicles subserving the superior rectus and the levator palpebrae muslces from brain stem infarction and presenting the characteristics of central disruption of binocular vision fusional amplitudes. CASE REPORT: One patient with an old intracranial aneurysm and with old and recent brain stem infarcts and no other neurological manifestations, demonstrating findings characteristic of isolated paresis of the superior rectus and levator palpebrae muscles is reported. CONCLUSION: This dual involvement of the superior rectus and levator palpebrae muscles supports the anatomical arrangement of the ocular motor nucleus fascicles in the midbrain, clarified by experimental studies on animals and clinical data in humans and emphasizes the juxtaposition of the superior rectus and levator palpebrae fascicles and placing the levator palpebrae mucle fascicle lateral to the medial rectus fascicle in the midbrain. The comitant vertical deviation and the negative Bielschowsky head tilt test support the vertical rectus muscle involvement. The constant diplopia with only 4 prism diopters of hypotropia and with the absence of fusional amplitudes evokes disruption of central binocular fusion.

Tenon's capsule pseudo-tendon repair of a lost medial rectus muscle.

BACKGROUND AND PURPOSE: The loss of an extraocular muscle is an infrequent but serious complication of strabismus surgery. The purpose is to show that a tailored tongue of Tenon's capsule, 7.0 mm to 9.0 mm wide and 12.0 mm to 14.0 mm long, fashioned in the direction of a lost medial rectus muscle and attached at the site of its original insertion can restore full ocular movement in the direction of action of the muscle. CASE REPORT: Thisis a report of a patient who underwent re-shaping and attachment of Tenon's capsule to the original insertion of the medial rectus muscle that ruptured during attempted medial rectus recession for longstanding esotropia with medial rectus restriction. The procedure was done immediately following the loss and failure to retrieve the lost muscle. RESULTS: Residual large angle esotropia and good adduction were obtained postoperatively despite a severed and consecutively lost medial rectus muscle. CONCLUSION: A tongue of Tenon's capsule, attached at the original site of a lost extraocular rectus muscle in a young adult, works as a pseudo-tendon successfully restoring function in the direction of action of that muscle.

Inferior oblique overaction/contracture following retrobulbar anesthesia for cataract extraction with a positive Bielschowsky Head Tilt test to the contralateral shoulder. A report of one case.

BACKGROUND AND PURPOSE: This is a report of a patient with diplopia, hypertropia, extorsion and a positive Bielschowsky Head Tilt Test following retrobulbar anesthesia, due to an inferior oblique muscle overaction-contracture. CASE REPORT: Oculomotor and sensorimotor examinations and ocular motility recordings and Bielschowsky Head Tilt Test demonstrated overaction characteristics overpowering the contracture characteristics of the involved inferior oblique muscle. RESULTS: Weakening of the overacting inferior oblique eliminated the vertical and torsional deviations and the forced head tilt difference upon tilting the head to either shoulder. It also normalized ocular motility and resulted in a symptom-free patient. CONCLUSION: Oblique muscle dysfunction with vertical and torsional deviations and a positive Bielschowsky Head Tilt Test can result from retrobulbar anesthesia.

Intermittent exotropia with high AC/A ratio: is it a bane to surgical cure? Some facts and fictions of the two clinical tests: occlusion of one eye and the use of +3.00 spherical lenses.

BACKGROUND AND PURPOSE: To review the multiple factors in intermittent exotropia (X(T)) responsible for the discrepancy between the distance and near deviations; to challenge the classification of X(T) into types according to the two standard clinical tests of occlusion of one eye and the use of +3.00 D spherical lenses at near by demonstrating the pitfalls of these two tests, as in X(T), masquerading as high AC/A ratio at times or as strong proximal fusional convergence at other times. METHODS OF STUDY: Fifteen patients demonstrating findings characteristic of X(T) with so-called high AC/A ratio are reported. Fourteen patients had an exodeviation initially. The fifteenth had become exotropic following medial rectus recessions for infantile esotropia. Fourteen patients had bilateral lateral rectus recession and one had unilateral lateral rectus recession. RESULTS: The only patient who did develop a long term postoperative overcorrected high AC/A ratio esotropia was the patient who had initially an infantile esotropia. Of the other 14 patients initially X(T) none developed a long term postoperative overcorrected high AC/A ratio esotropia. Fifty % of these were "cured" (OT +/- 8 delta) and 50% had a "significant (> or = 8 delta) recurrence" of their exodeviation. CONCLUSION: Patients with intermittent exotropia and significantly more exodeviation at distance than at near, and classified to have high AC/A ratio by occlusion of one eye and the use of +3.00 spheres at near, do not necessarily have a high accommodation-convergence relationship but rather, other factors mimicking this high AC/A relationship. They do not necessarily develop a postoperative overcorrected high AC/A ratio esotropia.