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Biomedical subjects

B J Kushner

Publications and source records attributed to B J Kushner.

124 records · Page 7Linked to original sources
PubMed1977

Retrolental fibroplasia: I. Clinical observations.

The changes occurring in retrolental fibroplasia were studied in 97 premature infants with fundus photography and fluorescein angiography. The macrovascular lesion of proliferative retrolental fibroplasia was identified as a functioning arteriovenous shunt. The microvascular abnormalities were capillary tufts, collaterals, capillary-free zones, and neovascular membranes. Regression was signaled by the ingrowth of capillaries from the shunt into the avascular retina. Cicatrization was characterized by persistence of the vascular abnormalities of the proliferative phase and organization of the avascular retina into a contracting scar.

Fluorescein Angiography↗
PubMed1977

Paradoxical pupillary responses in congenital stationary night blindness.

Three unrelated boys, ages 2, 6, and 10 years, who have congenital stationary night blindness with myopia and a Schubert-Bornschein-type electroretinogram finding, were found to show a "paradoxical" pupillary constriction in darkness. When examining room lights are turned out, the patient's pupils briskly constrict and slowly dilate. Older night blind male relatives of these boys did not show this abnormal constriction to darkness.

Adolescent↗
PubMedDate not supplied

Evaluation of the posterior fixation plus recession operation with saccadic velocities.

I performed a posterior fixation of the medial rectus in seven patients with convergence excess esotropia and successfully reduced their esotropia at near. Postoperative saccadic velocity testing did not reveal the expected decrease in saccadic velocity as the eye moved increasingly into the field of action of the operated muscle. Posterior fixation of a rectus muscle may enhance the effect of the standard recession operation by increasing the amount of slack created in the functional part of the muscle after recession. Also, it may make a large percentage of the muscle fibers ineffective.

Adult↗
PubMedDate not supplied

Ocular torsional movements in humans with normal and abnormal ocular motility--Part I: Objective measurements.

Using a corneal marker and cinematography, we analyzed ocular torsional movements during forced head tilt in three patients with superior oblique palsy before and after ipsilateral inferior oblique recession and compared them to those of normal subjects. As the head is tilted in normal subjects, the eye lags behind the head in a slow rolling movement. Periodic rapid wheel-like movements occur in the direction of head tilt which do not completely allow the eye to catch up with the head. This results in a partial compensatory intorsion on ipsilateral head tilt and extorsion on contralateral head tilt. In patients with superior oblique palsy, the rapid extorsional movement on ipsilateral head tilt is greater and faster than in the normal, but becomes slower after inferior oblique recession, indicating it comes from the overacting inferior oblique. The rapid intorsional movement seen during contralateral head tilt is absent in patients with superior oblique palsy, but appears in a diminished form after inferior oblique recession.

Adolescent↗
PubMedDate not supplied

The role of ocular torsion on the etiology of A and V patterns.

Theoretically, the torsion of the globe produced by primary oblique overaction results in a vertical displacement of the insertions of the horizontal recti and a horizontal displacement of the insertions of the vertical recti. This should alter the vectors of the forces exerted on the globe by the rectus muscles so that the horizontal recti become partial elevators or depressors and the vertical recti become increasing abductors or adductors. This change in force vectors tends to enhance the A or V pattern that results from oblique dysfunction. I propose that the etiology of A and V patterns is the result of a complex interplay between all of the extraocular muscles and present a clinical series to suggest the validity of that theory.

Adult↗
PubMedDate not supplied

Ocular torsional movements in humans with normal and abnormal ocular motility: Part II--Subjective observations.

A technique is described by which subjects, using a Maddox rod, can subjectively appreciate the dynamic torsional movements that occur at the end of forced head tilt. The subjective responses of a large series of subjects with normal ocular motility confirm my previous observations that at the end of ipsilateral head tilt the eye is undergoing an extorsional movement and at the end of contralateral head tilt, an intorsional movement. Observations made in patients with oblique dysfunction confirm that the extorsional movements are largely produced by the inferior oblique and the intorsional movements by the superior oblique. This is consistent with the classic observation that a partial compensatory intorsion occurs after ipsilateral tilt, and extorsion after contralateral tilt, however, it suggests that this compensatory torsion occurs by a different mechanism than is classically taught. Patients with dissociated vertical divergence appear to have an abnormal response of the oblique muscles to change in head tilt.

Eye Movements↗
PubMedDate not supplied

The effect of oblique muscle surgery on the axis of astigmatism.

A series of 22 highly astigmatic eyes in 14 patients underwent surgery, either in the form of recessing the inferior oblique, tenotomizing the superior oblique, or tightening the superior oblique. The refractive errors obtained in a masked manner six months postoperative were compared to those preoperative. Weakening the inferior oblique or tightening the superior oblique produced a long-term incyclorotation (clockwise for right eyes and counterclockwise for left eyes) of the axis of astigmatism of approximately 10 degrees. Tenotomizing the superior oblique produced a long-term excyclorotation (counterclockwise for right eyes and clockwise for left eyes) of the axis of astigmatism of about 10 degrees.

Astigmatism↗
PubMedDate not supplied

Theoretical effects of surgery on length tension relationships in extraocular muscles.

The main effect of recession or resection of a rectus muscle is thought to be due to an alteration of its length-tension curve (Starling's Law). Because the subsequent straightening of the eye produces a movement of the new insertions of the rectus muscles either anteriorly or posteriorly in the orbit, the actual amount of tightening or shortening of the muscle is not equal to the amount of recession or resection. How much this phenomenon alters the true amount of tightening or shortening of a muscle has important implications in the determination of safe amounts of surgery, which may differ if one is operating on the fixing or non-fixing eye. In addition, the size of the globe should have an important role in determining the response per millimeter of surgery.

Biomechanical Phenomena↗
PubMedDate not supplied

Artifacts of measuring during strabismus surgery.

Several different artifacts can induce errors in measurements obtained during strabismus surgery. Fixating the severed rectus muscle stump with forceps during strabismus surgery can result in a temporary anterior displacement of the insertion. This may result in inaccuracies in determining the site to which the muscle is to be recessed. This displacement was quantified in a prospective masked manner and was found in some patients to result in as much as 1 mm of error. It can be prevented by measuring the recession prior to fixating the insertion stump with forceps; however, it cannot always be prevented by measuring from the limbus, which also introduces other artifacts due to geometric principles. An "advancement effect" occurs during a rectus muscle recession due to the mechanics of suture placement in the muscle. It was quantified in a masked manner and found to be approximately .5 mm in most cases. A "V" shaped deformity of the insertion stump may occur immediately adjacent to the forceps. This deformity frequently distorts the insertion by as much as several millimeters.

Humans↗
PubMedDate not supplied

Good visual outcome after endophthalmitis in an eye previously treated successfully for amblyopia.

A child with an extensive periorbital hemangioma developed an endophthalmitis caused by Staphylococcus aureus after her second strabismus surgical procedure. Treatment with vitrectomy and intraocular antibiotics and steroid resulted in preservation of her eye. Despite previous successful treatment for amblyopia in that eye, her visual acuity improved from hand motion during the acute episode of endophthalmitis to 20/40 -2.

Amblyopia↗
PubMedDate not supplied

How far can a medial rectus safely be recessed?

Previous studies have suggested that the location of the equator should be important in determining the site of a "safe maximum recession" of a rectus muscle, and that the location of the equator should be a function of axial length. Exactly where in relationship to the equator a muscle can be safely recessed has never been scientifically determined. Over a 4-year period, we measured axial length on all patients we operated on for strabismus. Using a previously derived formula, we were able to calculate the limbus-to-equator distance, given axial length. Based on our analysis of 28 patients in whom we recessed one or both medial recti posterior to the equator, we believe that recessions of the medial recti up to 1.5 mm posterior to the equator should not produce postoperative medial rectus underaction associated with an overcorrection, but recessions that are further than 1.5 mm posterior to the equator may do so. Recessions to a point greater than 11 mm from the limbus do not appear to be associated with late progressive overcorrection provided that the site of recession is not greater than 1.5 mm posterior to the equator. Using our previously determined formula for estimating the location of the equator, given axial length, we have generated easy-to-use reference tables for determining the location of the equator in terms of millimeters posterior to the limbus. Also, based on axial length data from 180 strabismus patients, we have generated an algorithm for predicting axial length, given age, and refractive error, which may be useful to the strabismus surgeon in predicting the location of the equator when A-scan ultrasonography is not available.

Algorithms↗
PubMedDate not supplied

Axial length estimation in strabismic patients.

BACKGROUND: Previous studies have indicated that axial length determination is important in strabismic patients for defining the limit for a safe maximum recession of the medial rectus. Also, the response to strabismus surgery may be, in part, a function of axial length. We previously published a formula for predicting axial length based on age and refractive error; however, its accuracy has not been tested in a patient population that is different from the one used to generate the formula. The purpose of this study is to test a formula for estimating axial length, given age and refractive error, in a population that is different from that from which it was generated. METHOD: We measured axial length using A-scan ultrasonography in 163 consecutive patients undergoing strabismus surgery. Twenty-nine patients were younger than 18 months of age; 134 patients were between 18 months and 10 years of age. We compared the measured axial length determination with the axial length value estimated by a formula generated from our previous published series. RESULTS: For patients younger than 18 months of age, the equation estimated axial length within 0.5 mm in 41.4% of patients, within 1.0 mm in 79.3% of patients, and within 1.5 mm in 93.1% of patients. For patients between 18 months and 18 years of age, the formula estimated axial length within 0.5 mm in 37.3% of patients, within 1.0 mm in 73.1% of patients, and within 1.5 mm in 87.3% of patients. CONCLUSIONS: The formula may be useful for the strabismus surgeon in estimating axial length when A-scan ultrasonography is not available in an operating room setting, particularly in congenital esotropes who require larger recessions in small eyes. If, however, A-scan ultrasonography is available, it is preferable to using the formula. The formula is not sufficiently accurate for use for calculating intraocular lens power.

Child↗
PubMedDate not supplied

The relationship between dissociated vertical divergence (DVD) and head tilts.

INTRODUCTION: Dissociated vertical divergence (DVD) has been associated with manifest head tilts. Also, DVD has been described as demonstrating a characteristic response to forced head tilt by increasing the size of the DVD on contralateral tilt. METHODS: A series of 116 consecutive patients with DVD associated with infantile esotropia were examined according to a predetermined protocol between 1989 and 1994. Each patient was examined for a manifest head tilt. Also, the response of the DVD to forced ipsilateral and contralateral head tilt was analyzed. In addition, 100 consecutive patients with manifest head tilts were examined and the etiology of the tilt determined. RESULTS: A manifest head tilt was present in 35% (26/74) of patients with an ocular fixation preference and no prior vertical muscle surgery. None of the patients with alternating fixation and a history of no vertical muscle surgery manifested a head tilt. Most patients responded in the classically described manner by increasing the size of the DVD on forced contralateral tilt and decreasing the size of the DVD on ipsilateral tilt. Atypical responses were not related to the presence of oblique overaction. DVD was the etiology in 9 of 100 consecutive patients with a manifest head tilt. CONCLUSIONS: Patients with DVD often manifest a head tilt. Most respond by increasing the size of the DVD on forced contralateral head tilt and decreasing on ipsilateral tilt. Atypical responses did not appear to be influenced by oblique overaction. DVD is a relatively frequent cause of manifest head tilts.

Adolescent↗
PubMedDate not supplied

Congenital ocular aberrant innervation--new concepts.

BACKGROUND: We have the impression that congenital aberrant innervations are more common than previously reported. Many varieties exist and typically involve the sixth nerve. The most common ocular miswirings are Duane's syndrome and Marcus Gunn jaw-winking ptosis. The second most common miswiring involves lateral rectus activation in upgaze causing a "Y" pattern exotropia (pseudo inferior oblique overaction). This commonly is confused with inferior oblique overaction but surgery on the obliques does not cure the condition. Lateral rectus recession and elevation are required. METHODS: We selected demonstrative cases from our practices to illustrate a variety of congenital aberrant innervations. A literature search for previous reported cases of aberrant innervations was performed. This report is an eclectic collection of observations of individual selected cases. RESULTS: We found aberrant innervations of unusual varieties. These miswirings involve simultaneous firing of the lateral rectus with other muscles, including: the ipsilateral superior rectus, causing "pseudo inferior oblique overaction"; the contralateral lateral rectus, causing synergistic divergence; the ipsilateral superior rectus, in upward saccades only; and the masticatory muscles, causing exotropia with sucking. The third nerve by itself rarely is involved in congenital miswirings, but commonly shows aberrant regeneration after traumatic injuries. We know of no cases of aberrant innervation involving the fourth nerve. SUMMARY: We present cases describing these congenital aberrant innervations and discuss a unifying hypothesis as to their typical involvement of the sixth nerve.

Blepharoptosis↗
PubMedDate not supplied

Ocular motility defects in patients with the Krupin valve implant.

To determine the prevalence of ocular motility defects following placement of a Krupin valve with disk and adjunctive mitomycin-C in glaucoma patients, a retrospective case series of all patients receiving a Krupin valve with disk and intraoperative mitomycin-C in a university-based referral practice was conducted. Each of the seven consecutive patients undergoing placement of a Krupin valve with disk in one eye because of uncontrolled glaucoma, developed significant primary position heterotropia or limitation of ocular rotations. One patient had significant postoperative diplopia. We conclude that the Krupin valve with disk used with intraoperative mitomycin-C can be associated with the development of ocular motility defects. The limitation of rotations appears to relate to the combined mechanisms of implant and cyst bulk and the displacement of the oculorotary muscles by the encapsulating cyst.

Adult↗