Kenneth W. Wright

Superior Oblique Silicone Expander for Brown Syndrome and Superior Oblique Overaction

Standard procedures for weakening the superior oblique muscle have been associated with significant complications in the treatment of superior oblique overaction and Brown syndrome. This article presents a new technique for weakening the superior oblique muscle by lengthening the superior oblique tendon. Lengthening is accomplished by a nasal superior oblique tenotomy, and by inserting a segment of medical grade silicone 240 retinal band between the cut ends of the tendon. This technique was performed on 18 patients (30 eyes), 14 (26 eyes) with superior oblique overaction, and four (one eye each) with Brown syndrome. Preoperatively, patients with superior oblique overaction demonstrated A-patterns between 20 prism diopters and 55 delta, and versions of +2 to +4 superior oblique overaction in at least one eye. Postoperatively, the A-pattern and overaction improved in each case, and 13 of the 14 patients had patterns 10 delta or less. Of the four patients with Brown syndrome, three showed marked improvement of elevation in adduction, without consecutive superior oblique palsy. One had no improvement, even after a second procedure, consisting of superior oblique tenectomy; this case probably represents a non-superior oblique restriction (ie, a pseudo-Brown syndrome). Based on these results, it appears that the silicone expander technique is useful in patients with superior oblique overaction and Brown syndrome secondary to tight superior oblique tendon. This technique allows a predetermined degree of tendon separation and a graded weakening of the superior oblique muscle. Furthermore, by controlling the cut ends of the tendon, the procedure is easily reversible and there is ready access to the tendon should reoperation be necessary for residual overaction.

The Fat Adherence Syndrome and Strabismus after Retina Surgery

The etiology of persistent strabismus after retina surgery has been poorly understood. Seven patients with acquired restrictive strabismus after retina surgery were surgically explored for the cause of the strabismus. In each case, the fat adherence syndrome was identified as playing a significant role in causing the restriction. In four patients, restriction secondary to the fat adherence syndrome was the sole cause of the strabismus. Other contributing causes included a misplaced muscle in two patients and a sponge under a muscle in one patient. Our conclusion is that the fat adherence syndrome is an important cause of restrictive strabismus after retina surgery and that this complication can be minimized by avoiding surgical maneuvers that violate Tenons capsule and expose extraconal fat.

Results of Late Surgery for Presumed Congenital Cataracts

We reviewed the results of cataract extraction and visual rehabilitation in 76 eyes of 47 infants and children with presumed congenital cataracts who were first seen after they were 10 months old. Eighteen patients underwent surgery for unilateral cataracts, including five patients with persistent hyperplastic vitreous, five with posterior lenticonus, one with a nuclear cataract, six with posterior subcapsular cataracts, and one with a lamellar cataract. Of these 18 patients, seven (39%) attained a visual acuity of 20/60 or better, one (6%) had a visual acuity of 20/100, and ten (60%) had a visual acuity of 20/200 or worse. Twenty-nine patients (62 eyes) underwent bilateral cataract extraction. The visual acuity could be measured in 22 patients (44 eyes). Visual acuity improved to 20/60 or better in 32 eyes (73%), was between 20/70 and 20/150 in 11 eyes (25%), and became worse than 20/200 in one eye (2%). Results were good in patients with persistent hyperplastic primary vitreous, posterior lenticonus, and bilateral cataracts.

Amniotic Membrane Transplantation for Restrictive Strabismus

PURPOSE To report the use of amniotic membrane transplant in patients with restrictive strabismus. DESIGN Retrospective, interventional case series. PARTICIPANTS Patients with restrictive strabismus treated with amniotic membrane transplantation. METHODS Chart review of 7 consecutive patients (8 eyes) who developed restrictive strabismus after periocular surgery and were treated with surgical removal of restrictive adhesions and placement of an amniotic membrane transplant. MAIN OUTCOME MEASURES Intraoperative findings to explain the mechanism of restrictive strabismus, and clinical postoperative results, including ocular alignment, ductions and versions, symptom relief, and resolution of diplopia. RESULTS Restrictive strabismus occurred after surgery for pterygium, retinal detachment, orbital floor fracture, dermoid cyst, and dermatochalasis. Restrictive strabismus was due to a combination of conjunctival contracture, fat adherence, or rectus muscle contracture. All patients developed postoperative scarring, with failed additional standard surgery to remove the adhesions, including 1 patient treated with mitomycin C for recurrent scarring after pterygium. Reoperation using amniotic membrane transplantation was associated with improvement of ocular motility in 6 of the 7 patients; 1 patient had recurrence of scarring with persistent diplopia. The remaining 6 of 7 patients had no significant recurrence of scarring, and motility remained stable during the follow-up period of 5 to 13 months. CONCLUSIONS Amniotic membrane transplantation seems to help prevent recurrence of adhesions in patients with restrictive strabismus caused by conjunctival scarring, fat adherence syndrome, or rectus muscle contracture. Use of an amniotic membrane transplant should be considered as a treatment option for these difficult cases of restrictive strabismus. FINANCIAL DISCLOSURE(S) The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Clinical Optokinetic Nystagmus Asymmetry in Treated Esotropes

BACKGROUND Monocular optokinetic nystagmus (OKN) asymmetry is associated with disruption of early binocular visual development. METHODS Three groups of treated esotropic patients and a group of normal controls were evaluated for the presence of clinically detectable monocular OKN asymmetry. Clinical assessment of monocular OKN asymmetry was performed by observing eye movements in response to a hand-held rotating drum. Asymmetry was quantitated on a scale of 0 to +3 OKN asymmetry. Clinical OKN asymmetry was evaluated in the following groups of patients: those with congenital esotropia treated with very early surgery achieving high-grade stereo acuity (group 1); those with congenital esotropia treated with late surgery achieving no stereopsis (group 2); those with acquired esotropia achieving high-grade stereo acuity after treatment with spectacle correction (group 3); and normal controls (group 4). RESULTS Two of the three patients in group 1 showed +3 OKN asymmetry despite having high-grade stereo acuity; the third one, who was surgically aligned earliest (13 weeks), demonstrated +1 OKN asymmetry. This patient achieved orthotropia, 40 seconds stereo acuity, perfect Randot stereo acuity, and had no dissociated vertical deviation or latent nystagmus. All 10 patients in group 2 (those with late alignment-after 1 year-and no stereo acuity) showed +3 OKN asymmetry. All four patients in group 3 (those with acquired hypermetropic esotropia and high-grade stereo acuity after treatment) and all 10 patients in the normal control group showed no OKN asymmetry. CONCLUSION Clinically obvious monocular OKN asymmetry can occur in patients with congenital esotropia who are aligned early and develop high-grade stereo acuity. Even brief periods of strabismus during the early period of binocular motor development can result in persistent OKN asymmetry. This suggests that binocular motor processing may develop distinct from, and prior to, the development of high-grade stereo acuity. OKN asymmetry appears to be a clinical sign of an insult to early binocular motor development.

Effect of a modified rectus tuck on anterior segment circulation in monkeys.

Removal of a rectus muscle results in permanent interruption of blood flow in the corresponding anterior ciliary artery, predisposing to anterior segment ischemia (ASI). A subhuman primate model of ASI was developed in order to study a novel muscle tuck procedure designed to preserve anterior ciliary artery circulation. Fluorescein angiograms were obtained before and after surgery to determine the effect of the muscle surgery on iris circulation. A total of 12 eyes from 12 cynomolgus monkeys underwent strabismus surgery consisting of tenectomy of all 4 rectus muscles in 3 eyes, tenectomy of 3 rectus muscles in 3 eyes, and tenectomy of 3 rectus muscles and muscle to sclera tuck of the remaining recti in 6 eyes. Postoperative angiograms documented preservation of perfusion in the distribution of the tucked muscle in all cases except one, in which there was iatrogenic trauma and disruption of anterior ciliary arteries. The modified tuck procedure thus appears to preserve anterior ciliary artery blood flow, and may be useful as a muscle strengthening procedure in patients predisposed to developing ASI.

C.57 C > T Mutation in MIR 184 is Responsible for Congenital Cataracts and Corneal Abnormalities in a Five-generation Family from Galicia, Spain

Abstract A c.57 C > T mutation in the seed region of MIR184 located at the 15q25.1 chromosomal region has been independently associated with autosomal dominant keratoconus with early-onset anterior polar cataract in the Northern Irish family and with autosomal dominant EDICT (Endothelial Dystrophy, Iris hypoplasia, Congenital cataracts, and stromal Thinning) syndrome. In this study we report a five-generation family originating in Galicia, Spain with early onset cataracts and variable corneal abnormalities which include non-ectatic corneal thinning and severe early-onset keratoconus. We identified a heterozygous c.57 C > T mutation in miR-184 in the proband and two additional affected relatives on the maternal side. This finding represents a third independent occurrence of this mutation in familiar ocular disease thus strengthening the link between miR-184 abnormalities and inherited eye defects.

Use of High Dose Chloral Hydrate for Ophthalmic Exams in Children: A Retrospective Review of 302 Cases

Although chloral hydrate sedation has been proposed as an alternative to evaluation under anesthesia for pediatric patients who are unable to cooperate with routine test procedures, a careful study of the drugs safety and effectiveness is lacking. This study reports the effectiveness and safety of high-dose chloral hydrate for ophthalmic examination in 302 patients between the ages of 1 month and 5 years. The patients had nothing to eat or drink for 4 hours prior to drug administration. The patients were monitored during sedation and until fully awake. Eighty-eight percent of the patients (266/302) were successfully sedated without a supplemental dose. There were no reports of any complications including emesis, respiratory distress or depression, behavioral problems, changes in vital signs, patient injury, or hospital admission. The high-dose chloral hydrate protocol described, results in safe and generally successful sedation of pediatric patients for ophthalmic examination.

Unilateral or asymmetric congenital ptosis, head posturing, and amblyopia.

PURPOSE To determine the prognostic implication of compensatory head posturing in patients with unilateral or asymmetric congenital ptosis. METHODS A retrospective review of 80 consecutive patients with unilateral or asymmetric congenital ptosis was performed. The presence of documented compensatory head posturing, age of onset, age of presentation, visual acuity, refraction, and amblyopia were recorded, and binocularity was tested. RESULTS Five of seven (71%), patients with unilateral or asymmetric congenital ptosis and compensatory head posturing had amblyopia. All of these patients had straight eyes and four of the five amblyopic patients had anisometropia of less than 2 diopters (D). CONCLUSION The high incidence of amblyopia in this group can occur in the absence of significant anisometropia and strabismus. This unusually high incidence of amblyopia in this subgroup of patients with unilateral or asymmetric congenital ptosis and compensatory head posturing warrants compulsive examination and prophylactic part-time occlusion therapy of the nonptotic eye until reliable vision testing can be performed.

Effect of decreasing target oxygen saturation on retinopathy of prematurity.

INTRODUCTION The authors of previous studies suggest that the oxygenation status of premature infants contributes to the development of retinopathy of prematurity (ROP). In this study we compared the incidence and severity of ROP before and after institution of a new neonatal intensive care unit oxygen protocol. METHODS A retrospective chart review was performed of all eligible inborn patients screened for ROP during the 2 years immediately before (Group 1) to and the 2 years after (Group 2) the initiation of a new oxygen protocol. In the new protocol, target oxygen saturation was adjusted from 90%-99% to 85%-93%. Treatment criteria adhered to Early Treatment for Retinopathy of Prematurity guidelines for the studys duration. RESULTS There were 387 infants in Group 1 and 386 infants in Group 2 (descriptive statistics adjusted for correlation due to multiple births). Mean birth weights (BWs) and gestational ages were 1,194 g and 29.2 weeks (ranges, 525-2,085 g; 23 2/7-39 6/7 weeks) for Group 1 and 1,139 g and 28.9 weeks (ranges, 520-2,500 g; 22 6/7-35 3/7 weeks) for Group 2 (p = 0.02/0.10). ROP developed in 32.7% of infants in Group 1 and 27.8% in Group 2 (p = 0.17). The incidence of ROP requiring treatment was 19.9% in Group 1 and 20.5% in Group 2 (p = 0.91). Subanalysis of infants with BW ≤ 1,000g (Group 1, n = 119; Group 2, n = 141) revealed ROP incidence of 75.1% versus 57.1%, respectively (p < 0.01); treatable disease occurred in 37.5% and 21.9% of affected infants (p = 0.19). CONCLUSIONS Lowering target oxygen saturation for inborn premature infants was associated with decreased incidence of ROP only in infants with BW ≤ 1,000 g. Severity of disease, including need for treatment, was similar in both groups.