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Biomedical subjects

J Zwaan

Publications and source records attributed to J Zwaan.

At least 19 recordsLinked to original sources
PubMed1998

Effectiveness and complications of mitomycin C use during pediatric glaucoma surgery.

PURPOSE: To examine the safety of mitomycin C (MMC) use in pediatric glaucoma surgery. DESIGN: Retrospective interventional case series. PARTICIPANTS: One hundred eighty pediatric glaucoma patients younger than 7 years of age (254 eyes) who underwent glaucoma surgery and were followed for at least 1 year participated. INTERVENTIONS: Surgeries consisted of trabeculectomy or combined trabeculotomy-trabeculectomy with adjunctive use of MMC. MAIN OUTCOME MEASURES: Control of intraocular pressure (IOP) and occurrence of complications were measured. An IOP below 21 mmHg without any additional medical or surgical treatment was considered a success. RESULTS: Primary congenital glaucoma was present in 98% of the patients. Sixty percent had a trabeculectomy, and 40% had a trabeculotomy-trabeculectomy. The combined surgery was performed mostly in infants up to 1 year of age. Complications were cystic bleb (19), bleb leak (4), retinal detachment (3), flat anterior chamber (3), cataract (2), and endophthalmitis (1). Children younger than 2 years of age had fewer complications but higher failure rates. The combined procedure in infants up to 2 years of age was moderately more successful (57%) than trabeculectomy alone (39%). Minimal complications seen in this group were more likely related to young age than to the type of surgery. Complications increased with time after surgery, with most occurring 2 years or more after surgery. CONCLUSIONS: Success of MMC-augmented glaucoma filtering surgery increased with age, as did the complication rate. Serious complications were uncommon in the authors' group of pediatric patients up to now. However, complications related to bleb thinning increased with time after surgery, and additional problems can be anticipated with longer follow-up.

Chemotherapy, Adjuvant↗
PubMed1998

Pediatric intraocular lens implantation. Surgical results and complications in more than 300 patients.

OBJECTIVE: The study aimed to review pediatric intraocular lens (IOL) implantations performed in the authors' institution for the past 7 years. STUDY DESIGN: The study design was a retrospective chart review. PARTICIPANTS: All children who underwent IOL placement between January 1, 1989, and January 31, 1996, at ages 2 to 16 years were studied. Follow-up was a minimum of 6 months up to 4 years with an average of 13 months. INTERVENTION: Placement of a primary or secondary posterior chamber IOL was performed. MAIN OUTCOME MEASURES: Visual acuity and possible complications were tabulated. RESULTS: Fifty-seven percent of the cataracts were caused by trauma, and 37% were infantile cataracts. Visual acuities of 20/40 or better were attained in 44% of eyes and visual acuities of 20/50 to 20/80 were attained in 27% of eyes. Visual acuities were better in children older than 4 years of age (P = 0.001). Compliance with amblyopia therapy improved vision (P = 0.004). Fibrinous membranes occurred in 41 eyes (13%), and posterior capsule opacification occurred in 120 eyes (39%). There were no significant differences in visual outcome and complications between primary and secondary implants (17%) or between capsular bag and sulcus fixation (27%). The first stable postoperative refraction was predicted accurately in most patients, based on the Sanders-Retzlaff-Kraff II (SRK II) formula and intraoperative corneal curvature and axial length determinations. The mean refraction differed from the goal by only +0.28 diopter and 84% were within +/- 2 diopters. A few patients showed large overcorrections or undercorrections. On average, no myopic shift occurred. CONCLUSIONS: Short-term results of IOLs implanted in children older than 2 years of age were favorable. Visual acuities obtained were better than 20/80 in 71% despite a high prevalence (28%) of penetrating trauma. Major complications were rare.

Adolescent↗
PubMed1998

Congenital fibrosis of the extraocular muscles type 2, an inherited exotropic strabismus fixus, maps to distal 11q13.

The extraocular fibrosis syndromes are congenital ocular-motility disorders that arise from dysfunction of the oculomotor, trochlear, and abducens nerves and/or the muscles that they innervate. Each is marked by a specific form of restrictive paralytic ophthalmoplegia with or without ptosis. Individuals with the classic form of congenital fibrosis of the extraocular muscles (CFEOM1) are born with bilateral ptosis and a restrictive infraductive external ophthalmoplegia. We previously demonstrated that CFEOM1 is caused by an autosomal dominant locus on chromosome 12 and results from a developmental absence of the superior division of the oculomotor nerve. We now have mapped a variant of CFEOM, exotropic strabismus fixus ("CFEOM2"). Affected individuals are born with bilateral ptosis and restrictive ophthalmoplegia with the globes "frozen" in extreme abduction. This autosomal recessive disorder is present in members of three consanguineous Saudi Arabian families. Genetic analysis of 70 individuals (20 affected individuals) reveals linkage to markers on chromosome 11q13, with a combined LOD score of 12.3 at the single nonrecombinant marker, D11S1314. The 2.5-cM CFEOM2 critical region is flanked by D11S4196/D11S4162 and D11S4184/1369. Two of the three families share a common disease-associated haplotype, suggesting a founder effect for CFEOM2. We hypothesize that CFEOM2 results from an analogous developmental defect to CFEOM1, one that affects both the superior and inferior divisions of the oculomotor nerve and their corresponding alpha motoneurons and extraocular muscles.

Blepharoptosis↗
PubMed1998

Combined intraocular and strabismus surgery.

BACKGROUND AND OBJECTIVE: To study the results of combined intraocular and strabismus surgery. PATIENTS AND METHODS: Combined surgery was done in 14 patients. In 10 of these patients, cataract and strabismus surgery were combined. One had a penetrating keratoplasty, and another required placement of a glaucoma valve implant. In one patient trabeculectomy, pupilloplasty, and lensectomy were done, and one patient needed repair of a leaking bleb. RESULTS: The strabismus of most patients was significantly improved. Eleven patients (79%) were orthophoric +/- 10 prism diopters (PD). Visual outcome was good in patients with no structural abnormalities who were compliant with occlusion therapy, if applicable. CONCLUSIONS: Combined intraocular and strabismus surgery has a success rate comparable with that of standard strabismus surgery.

Adolescent↗
PubMed1998

Topical tissue plasminogen activator appears ineffective for the clearance of intraocular fibrin.

BACKGROUND AND OBJECTIVE: To determine the efficacy of topical tissue plasminogen activator (tPA) for the resolution of postoperative or inflammatory intraocular fibrinous exudates. PATIENTS AND METHODS: Each treatment consisted of drops of 1 mg/ml tPA given 9 times 5 minutes apart. Records were reviewed and the results at 24 and 48 hours were recorded. Sixty-two patients had a total of 94 treatments. RESULTS: Fibrin exudates following intraocular surgery in 34 patients were treated 44 times. In 6 patients there was a positive result. Fibrin associated with intraocular infection was treated in 9 patients. None showed clear improvement. Nineteen patients had a total of 34 treatments for poorly controlled intraocular pressure (IOP) after glaucoma surgery. Five patients showed adequate control of the IOP, 12 did not change, and 2 had a questionable improvement. Eleven patients had adequate IOP control after additional treatment. Seven required suture lysis, 2 ab interno bleb revision, and 2 YAG capsulotomy or iridotomy to reduce the IOP to an acceptable level. CONCLUSIONS: Within the limits of this retrospective study and taking into account that fibrin may resolve spontaneously, it appears that topical tPA drops are not effective for the liquefaction of intraocular fibrin after surgery or in association with intraocular inflammation. They did not improve IOP control after glaucoma surgery.

Administration, Topical↗
PubMed1997

The anatomy of probing and irrigation for congenital nasolacrimal duct obstruction.

In this study, an easily palpable landmark, the supraorbital notch or foramen, was used to simplify the localization of the nasolacrimal duct during the probing procedure. The notch was palpated in 50 patients of a pediatric clinic. The topographic anatomy of the notch in relation to the lacrimal drainage system was studied in 10 skulls. The supraorbital notch is a convenient landmark for the guidance of a probe into the nasolacrimal canal. This technique should reduce the failure rate of probing without the need for infracturing of the lower turbinate or silicone intubation.

Adolescent↗
PubMed1997

Treatment of congenital nasolacrimal duct obstruction before and after the age of 1 year.

BACKGROUND AND OBJECTIVES: The treatment of congenital nasolacrimal duct (NLD) obstruction continues to be a subject of controversy. Some authors advocate early probing and irrigation in an office setting, whereas others recommend that the procedure be performed under general anesthesia when the child is at least 1 year old. The focus of this study was to compare the results of probing and irrigation of congenital NLD obstruction among children younger than 1 year of age, those 1 to 2 years of age, and those older than 2 years. PATIENTS AND METHODS: The author reviewed the records of 120 patients, ranging in age from 3 weeks to 30 years, with 153 cases of NLD obstruction. Eighty-five patients (110 cases of NLD obstruction) underwent probing and irrigation. RESULTS: Complications of NLD obstruction occurred in 12 patients; 75% of these patients were younger than 1 year of age. In group 1 (patient age < 1 year) there were 37 probings with 1 failure (3%). Group 2 (patient age = 1-2 years) had 43 probings and 5 failures (12%). In group 3 (patient age > 2 years), 30 NLDs were probed with 2 failures (7%). However, these differences were not significant (P = .13 between groups 1 and 2; P = .42 between groups 1 and 3). CONCLUSION: In this study, the postponement of probing and irrigation for congenital NLD obstruction beyond the age of 1 year did not result in an increased rate of failures or complications.

Adolescent↗
PubMed1997

The long-term effects of an accidental injection of depot corticosteroids in an infant eye.

A 4-month-old infant received an accidental intraocular injection of methylprednisolone while undergoing penetrating keratoplasty for congenital, hereditary endothelial dystrophy. This was not discovered until 4 months later, at which time the intraocular pressure (IOP) was increasing and an early cataract was forming. A lensectomy and vitrectomy were performed when the child was 12 months old. The IOP remained higher than that of the fellow eye, but the recovery was otherwise uneventful. This indicates that intraocular depot steroid may be tolerated, except when there is the occurrence of known pharmacologic side effects.

Anti-Inflammatory Agents↗
PubMed1996

Simultaneous surgery for bilateral pediatric cataracts.

BACKGROUND AND OBJECTIVES: To perform a review of the literature comparing the safety of bilateral simultaneous lensectomies in children versus the risk of more than one general anesthesia within a short time frame, and to study the results of bilateral surgery in a small group of patients. PATIENTS AND METHODS: Bilateral simultaneous lensectomies were performed in 9 children (18 eyes), in whom increased anesthetic risks warranted this approach. RESULTS: There were no postoperative complications for at least 6 months. CONCLUSION: Data in the current literature on endophthalmitis after cataract surgery and on the risks of repetitive anesthesia are inadequate to weigh the risk of bilateral endophthalmitis against the reduced risk of one anesthesia versus two and the advantages of simultaneous early visual rehabilitation. Until such information becomes available, simultaneous removal of bilateral infantile cataracts should probably be reserved for selected cases where the anesthetic risk is higher than average.

Anesthesia, General↗
PubMed1996

Strabismus induced by radial keratotomy.

The history of a woman who developed diplopia after radial keratotomy is reported. Examination showed that this was the result of the appearance of accommodative esotropia. Some complications of refractive surgery reported in the literature were reviewed. It is the current policy of the U.S. military services to disquality an applicant for entry who has undergone refractive surgery. Based on this review of complications it is argued that this is still the correct policy.

Adult↗
PubMed1996

Eye injuries during training exercises with paint balls.

The use of paint balls, increasingly popular for war games and survival games, has recently been introduced for certain military training exercises. We treated two soldiers who had severe permanent ocular damage after being hit by these balls. Both removed their goggles after their vision was obscured with paint from a hit on these protective lenses. They were then hit for a second time, resulting in the eye injury. Based on these cases and on a literature review, we conclude that protective eye gear should be mandatory when paint pellets are used. It is essential that service members participating in such exercises be instructed not to remove their protective goggles under any circumstances.

Adult↗
PubMed1994

Neuron-specific enolase expression during eye development in the chicken embryo.

Neuron-specific enolase has been used by others as a marker for the identification of cells of presumed neural crest origin in the human eye. The contributions of neural crest to the ocular tissues have been studied most definitively in the chicken embryo. The developing chicken eye was therefore chosen to further investigate the usefulness of neuron-specific enolase as a neural crest marker. Chicken embryos of various development stages were processed for the immunohistochemical localization of neuron-specific enolase with two different specific antisera. The nerve fiber layer of the neural retina and the optic nerve reacted positively. The first weak staining was found at day 10; it became rapidly stronger during the next 2 days. A positive reaction was also observed in the ciliary ganglion. In contrast, no staining was found in tissues of known neural crest origin. Cornea, sclera, trabecular tissues and iris stroma remained negative throughout the developmental stages studied. Therefore, neuron-specific enolase can not be used as a reliable marker of neural crest derived cells, at least in the chicken embryo. Unexpectedly the lens epithelium showed moderate neuron-specific enolase activity beginning on day 5. alpha-Enolase is an important crystallin in the lens of some species, particularly the turtle. It has also been demonstrated to be present in the chicken lens in a fairly high concentration. It is possible, that neuron-specific or gamma-enolase has a similar role in the chicken lens.

Animals↗
PubMed1993

Detection of ascorbic acid in the eye of the early chicken embryo by silver staining.

Ascorbate is found in high concentrations in the aqueous, lens and retina of a variety of animal species. Several functions have been proposed for this, including a vital role in aqueous secretion. We investigated the possible presence of ascorbate in the early embryonic chicken eye as a marker for the differentiation of the ciliary epithelium. Embryonic chicken eyes were processed for histochemical demonstration of ascorbate by silver staining. A strongly positive reaction was found in the interstitial matrix between the lens rudiment and the optic vesicle of the 2-day chicken embryo. By 3 days, with lens and optic cup separating from each other, the silver grains were concentrated in the vitreous cavity, primarily in a band-like configuration between the lens equator and the rim of the optic cup, which is the presumptive ciliary epithelium. A weaker reaction was seen in the lens vesicle and primitive neural retina. During the second and third day of incubation the optic vesicle is just beginning to expand. The appearance of ascorbic acid in the newly formed vitreous cavity at this time may indicate its importance in the biosynthesis of the matrix that is filling the expanding optic vesicle.

Animals↗
PubMed1992

Comparison of ascorbic acid levels in the eye and remainder of the chicken embryo during development.

Ascorbic acid was not detectable in egg white and egg yolk of fertilized eggs prior to incubation. It was demonstrated in the embryo at 5 days of incubation and its content in the eyes and other parts of the embryo increased with the embryo's age. Ascorbic acid of the eyes rose rapidly after day 6 during maximal eye growth and reached a peak by days 10-14 when the expansion of the eyes began to level off. Ascorbic acid content of the eyes decreased thereafter, while ascorbic acid in the head and the body tissues continued to rise up to the time of hatching. Whether this rapid increase of ascorbic acid concurrent with the increase of eye diameter indicates a role for ascorbic acid in the growth of the embryonic eye remains to be determined.

Animals↗
PubMed1987

Accumulation and distribution of sulfated materials in the maturing mouse lens capsule.

Lenses of late gestational and postnatal normal-eyed mice were tested for accumulated sulfated materials by using Spicer's high-iron-diamine staining method and also for newly incorporated sulfate autoradiographically following administration of 35SO4 either in vivo or in isolated and organ-cultured lenses. Accumulated and newly incorporated sulfate was observed in all lenses for each age group tested. Discrete regional differences were seen in histochemical staining patterns for sulfate on the lens capsule in specimens of all ages, and distinct laminar zonations were seen in the various regions of the capsule in older specimens. Typically, the anterior and equatorial regions of the capsule demonstrated three histochemically distinct laminar zones while the posterior capsule usually demonstrated two laminar zones. Autoradiographic results indicated that sulfate was indeed being incorporated into these regions, and in the same general pattern as seen with histochemistry. The materials were largely insensitive to testicular hyaluronidase but were preferentially sensitive to nitrous acid digestion, indicating the presence of capsular heparan sulfates. Autoradiographic results from organ-cultured lenses indicated that this tissue itself is a primary source of these materials.

Aging↗
PubMed1986

Abnormal accumulation of sulphated materials in lens tissue of mice with the aphakia mutation.

Sulphated materials were tested for in the eyes of late gestational and postnatal normal mice and mice with the aphakia mutation using Spicer's high iron diamine staining method. Qualitative identification of these materials was attempted with bovine testicular hyaluronidase and nitrous acid digestion methods. The grossly abnormal morphology of the aphakia lens made it necessary to confirm identification of lens-derived tissue by testing for lens crystallins using standard immunohistological methods. As seen in normal mouse lens maturation, accumulated inter- and intracellular sulphated materials were observed in aphakia lens tissue from just before birth through juvenile maturation. Large cyst-like structures consisting of lens-derived tissue were commonly seen in the eyes of young postnatal mutant mice. Sulphated materials formed basal lamina-like structures on many of these lens-derived units, but a well-defined lens capsule never formed. Abnormal fibrillar structures rich in sulphated materials were seen in the intraocular cavity in many older mutant specimens, most of which were largely resistant to both digestion methods. These results indicate that the potential to elaborate sulphated materials qualitatively similar to those seen in normal mouse lens maturation is present in the aphakia mutant, although the mode of accumulation is grossly disturbed.

Animals↗
PubMed1985

Ocular abnormalities in mucolipidosis IV.

Systemic findings in a 23-year-old white man with mucolipidosis type IV included early delayed psychomotor development, mental retardation, and mild facial dysplasia. There was urinary excretion of chondroitin sulfate. Ophthalmologic examination showed corneal haze, pigmentary retinopathy, and severe optic atrophy. Light microscopy showed massively engorged superficial and intermediate epithelial cells of both the cornea and the conjunctiva. By transmission electron microscopy these contained fine granular material consistent with acid mucopolysaccharide and concentric lamellar bodies presumably representing phospholipids. This storage phenomenon was also found in macrophages, plasma cells, ciliary epithelial cells, Schwann cells, retinal ganglion cells, and vascular endothelial cells. Light microscopy also disclosed early cataract formation, marked outer retinal degeneration, and optic atrophy.

Adult↗