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Biomedical subjects

Ken K Nischal

Publications and source records attributed to Ken K Nischal.

17 recordsLinked to original sources
PubMed2006

Amniotic membrane transplantation in children with symblepharon and massive pannus.

OBJECTIVE: To report our pediatric experience with amniotic membrane transplantation for ocular surface and forniceal reconstruction. METHODS: Retrospective case review of children who underwent superficial keratectomy, symblepharon lysis, and forniceal reconstruction using amniotic membrane transplantation. The underlying diagnosis, visual acuity, level of discomfort at first and last visits, and surgical details were noted. RESULTS: Four patients (5 eyes) were included. Two patients had epidermolysis bullosa (1 recessive dystrophic and 1 junctional), 1 had laryngo-onychocutaneous syndrome, and 1 had measles-related keratitis and was positive for human immunodeficiency virus. Their mean age when initially seen was 8.7 years (age range, 4-16 years), and mean follow-up was 18.25 months (range, 12-29 months). The mean visual acuity preoperatively was 1.1 logMAR (logarithm of the minimum angle of resolution) (range, 1-1.3), and postoperatively was 0.7 (range, 0.2-1.2). All patients experienced increased ocular comfort with anatomical restoration of corneal and conjunctival surfaces. Visual acuity improved in 3 eyes. Only the patient with laryngo-onychocutaneous syndrome had recurrence of granuloma, at 9 months after surgery. CONCLUSION: Amniotic membrane transplantation with symblepharon lysis is effective for ocular surface reconstruction in the management of epidermolysis bullosa and other conditions that cause corneal scarring and symblepharon in children. In this small series, children with epidermolysis bullosa fared better and the effects of surgery lasted longer compared with patients with other causes of symblepharon and massive pannus.

Adolescent↗
PubMed2006

Monitoring visual function in children with syndromic craniosynostosis: a comparison of 3 methods.

OBJECTIVE: To compare visual acuity, optic disc appearance, and transient pattern reversal visual evoked potentials as markers of possible visual dysfunction in children with syndromic craniosynostosis. METHODS: Serial visual acuity, optic disc appearance, and pattern reversal visual evoked potential data were recorded in 8 patients with syndromic craniosynostosis before and after cranial vault expansion. The pattern reversal visual evoked potentials were analyzed using linear regression modeling, applied to the N80 to P100 amplitude. RESULTS: Serial optic disc appearances were available for all 8 patients and visual acuities for 7 patients. The visual acuity deteriorated in only 1 patient, improved in 4, and fluctuated in 2, before surgery. Of the 8 patients, 3 showed no papilledema in either eye at any time, 3 showed progressive bilateral swelling before surgery, and 2 exhibited only unilateral disc swelling. In all 8 patients, there was a trend for the N80 to P100 amplitude to decrease before surgery and to increase, in all but 2 patients, after surgery. CONCLUSIONS: This study suggests that neither optic disc appearance nor visual acuity assessment alone is a reliable marker of potential visual dysfunction in children with syndromic craniosynostosis. It also suggests that the pattern reversal visual evoked potential can provide early evidence of visual dysfunction before vault expansion surgery in these children; this dysfunction may recover postoperatively.

Child↗
PubMed2006

Five-year experience of the 2-incision push-pull technique for anterior and posterior capsulorrhexis in pediatric cataract surgery.

PURPOSE: To describe the authors' 5-year experience of the 2-incision push-pull (TIPP) technique for pediatric anterior and posterior capsulorrhexis formation. DESIGN: Retrospective descriptive study over a 5-year period. PARTICIPANTS: A total of 84 eyes of 63 patients who had undergone cataract surgery in 1 center. METHODS: Retrospective review of all consecutive patients who underwent pediatric cataract extraction with planned intraocular lens implantation and TIPP rhexis between January, 1999, and August, 2004. Any lost capsulorrhexis, or capsular tears at any stage of the operation, and the relation of optic size to anterior capsulorrhexis size were noted. MAIN OUTCOME MEASURES: Complications during TIPP rhexis formation and any late complications at last visit. RESULTS: The mean age at operation was 70.21 months (range, 4 weeks-18 years). All eyes had anterior TIPP rhexis; 41 eyes also had posterior TIPP rhexis, and there were no anterior or posterior capsulorrhexis loss or tears while performing the technique. In no patient in whom TIPP rhexis was performed for the posterior capsule was there an inadvertent vitreous loss during rhexis formation. All eyes had anterior rhexis diameters that were smaller than the optic diameter (5.5-6.0 mm), approximately 4 to 4.5 mm in diameter. Four capsular tears were reported; 1 tear occurred during irrigation and aspiration and the others during rigid lens insertion. No late complications were noted. CONCLUSIONS: Our 5-year experience with the TIPP rhexis in pediatric cataract surgery has shown this to be a reliable method for producing a consistent-size capsulorrhexis opening in both anterior and posterior capsulorrhexis.

Adolescent↗
PubMed2005

Unilateral keratoconus in a child with chronic and persistent eye rubbing.

PURPOSE: To report a case of unilateral keratoconus in a 7- year-old female, secondary to chronic persistent eye-rubbing in the absence of any systemic condition. DESIGN: Observational case report. METHODS: In the case of this child, no organic cause was found to explain the onset of keratoconus other than persistent eye-rubbing in the affected eye. RESULTS: Nocturnal eye padding was instigated and the condition stabilized. She was reviewed over a 2-year period of follow-up. CONCLUSIONS: Eye-rubbing has been implicated in the pathogenesis of keratoconus. Eye-rubbing is also often a feature of a number of conditions linked to keratoconus such as Down syndrome, atopic keratoconjunctivitis, mental retardation, and Lebers' congenital amaurosis. There are a number of reports linking eye-rubbing and keratoconus in children, typically in relation to these conditions. However, in this case the keratoconus was secondary to chronic and persistent eye-rubbing in a healthy child.

Child↗
PubMed2005

The value of visual evoked potentials in the evaluation of periorbital hemangiomas.

PURPOSE: To present a case of a child with an extensive facial hemangioma in whom the suspicion of intracranial involvement was raised by visual evoked potential (VEP) evaluation. DESIGN: Observational case report. METHODS: VEP analysis was performed using flash and pattern stimuli to determine whether treatment intervention other than occlusion therapy was needed. RESULTS: VEP analysis indicated a marked transoccipital asymmetry in the flash and pattern VEP suggestive of right hemispheric dysfunction. Neuroimaging showed intracranial extension of the hemangioma. CONCLUSION: The VEP evaluation is a noninvasive technique performed in the awake child. This case highlights the usefulness of VEP analysis in the management of extensive periocular capillary hemangiomas and its use as a modality to identify potential intracranial involvement. Large plaquelike facial capillary hemangiomas may have possible underlying dural involvement suggestive of PHACES syndrome.

Amblyopia↗
PubMed2005

Preoperative assessment of secondary intraocular lens implantation for aphakia: a comparison of 2 techniques.

PURPOSE: To compare the preoperative evaluation of secondary intraocular lens (IOL) implantation in aphakic adults following cataract extraction in childhood using slitlamp examination and high-frequency ultrasound (HFU). METHODS: In a prospective case series, patients who had had lensectomies for congenital cataracts without primary implantation IOL were evaluated for secondary IOL insertion. Slitlamp examination and HFU were performed to study the degree of ciliary sulcus support and iridocapsular adhesions. The choice of IOL (posterior sulcus supported or anterior chamber) was compared using the 2 techniques. RESULTS: Nine eyes of 5 patients (3 men and 2 women aged 15 to 40 years) were assessed for secondary IOL insertion. Clinical slitlamp examination suggested that 3 of 9 eyes had inadequate sulcociliary support, but HFU of these eyes revealed more than adequate capsular remnants. In all 9 eyes, sulcus-supported posterior chamber IOLs were implanted. No postoperative complications were observed, and no patients required surgery for dislocated IOL. CONCLUSIONS: High-frequency ultrasound is a useful adjunct for the preoperative assessment of secondary ciliary sulcus-supported IOL implantation in aphakic patients who had congenital cataract extraction without IOL implantation. In patients in whom inadequate dilation precludes the detection of capsular support, posterior ciliary sulcus-supported secondary IOL implantation should be considered preoperatively. Although the technique enhances surgical planning and informed patient consent, the final decision occurs at the time of surgery with direct visualization of the ciliary sulcus support.

Adolescent↗
PubMed2004

Fourth and sixth cranial nerve injury after halo traction in children: a report of two cases.

BACKGROUND: Spinal traction is the application of a longitudinal force to the spinal column as a means of stabilizing a damaged or abnormal spine. Although not well documented in the ophthalmic literature, complications include cranial nerve palsies, with the sixth nerve being most commonly affected. Fourth nerve palsies have not previously been reported to our knowledge. We present 2 cases of combined fourth and sixth palsies after cervical traction. METHODS: Retrospectively, we reviewed the ophthalmic findings in 2 children with diplopia after spinal traction. RESULTS: Case 1 suffered a traumatic rotatory atlantoaxial subluxation and underwent halo traction. Case 2 required traction to correct a scoliosis secondary to osteogenesis imperfecta. In both cases, sixth nerve palsies were apparent soon after traction. Careful orthoptic examination revealed additional fourth nerve involvement. After 3 months, both cases showed partial resolution of the cranial nerve injuries. CONCLUSIONS: Cranial nerve injury may occur with spinal traction. Fourth nerve palsy may be underreported because of masking by a coinciding sixth nerve palsy.

Abducens Nerve Injury↗
PubMed2003

Foster-type modification of the Knapp procedure for anomalous superior rectus muscles in syndromic craniosynostoses.

PURPOSE: To describe the surgical management of anomalous superior rectus muscles in patients with syndromic craniosynostoses. METHODS: Retrospectively reviewed were case notes of 3 patients with vertical deviations that were thought to have anomalous superior rectus muscles. RESULTS: All 3 patients had hypotropia preoperatively, and 2 had coexisting exotropia. Two patients exhibited massive subconjunctival fibrosis intraoperatively, but none had undergone previous strabismus surgery, although they had undergone craniofacial procedures. Orbital imaging (either computed tomographic or magnetic resonance imaging scans) confirmed an absent or thinned superior rectus muscle in all 3 patients. All 3 underwent a Knapp procedure with appropriate recession and resection of the transposed horizontal rectus muscles if indicated. A nonabsorbable suture was placed in the sclera at the upper border of each horizontal rectus muscle to draw this border closer to the vertical midline, approximately 16 to 18 mm from the limbus (Foster-type modification). In each case, the hypotropia and upgaze were improved but not completely normalized. CONCLUSIONS: A Foster-type modification of the Knapp procedure satisfactorily corrected the hypotropia in these patients. Orbital imaging can confirm the presence of an anomalous superior rectus muscle. The massive subconjunctival fibrosis may be explained by the type of previous craniofacial surgery the patients had undergone.

Adolescent↗
PubMed2003

Phenotypic diversity and mutation spectrum in hypotrichosis with juvenile macular dystrophy.

Hypotrichosis with juvenile macular dystrophy is a rare autosomal recessive disorder characterized by abnormal growth of scalp hair during infancy, and by the later occurrence of macular degeneration leading to blindness during the first to third decade of life. Hypotrichosis with juvenile macular dystrophy was recently shown to result from mutations in CDH3 encoding P-cadherin. In this study, we assessed 27 individuals, including nine patients, belonging to five families in an attempt to characterize further the CDH3 mutation spectrum and delineate possible phenotype-genotype correlations. Deleterious biallelic mutations, predicted to lead to the translation of a dysfunctional protein, were found in all affected individuals. Four of these mutations are novel. Affected individuals of two large separate apparently unrelated families of Arab Israeli origin were found to carry the same homozygous mis-sense mutation (R503H) in exon 11 of the CDH3 gene. This mutation, which alters a Ca2+-binding site in the fourth extracellular domain of P-cadherin, was previously described in a third unrelated Arab Israeli family. Using haplotype analysis for a series of polymorphic markers encompassing the CDH3 gene, we obtained evidence suggesting a founder effect for R503H in the Arab Israeli population. We also compared the dermatologic and ophthalmologic features of 22 hypotrichosis with juvenile macular dystrophy patients with known recessive mutations in CDH3. Whereas hair paucity and macular degeneration were found in all patients, we noticed significant interfamilial and intrafamilial differences in hair morphology, associated skin findings as well as severity and age of onset of visual disability. Altogether, our results obtained in a series of families of various ethnic origins firmly establish mutations in CDH3 as the proximal cause of hypotrichosis with juvenile macular dystrophy and demonstrate genetic homogeneity as well as phenotypic heterogeneity in this disorder.

Cadherins↗
PubMed2003

Hypotension and bradycardia in infants after the use of topical brimonidine and beta-blockers.

Brimonidine is a selective alpha-2 adrenergic agonist used to treat glaucoma. There have been several reports of central nervous system depression after its use in infants. We observed rapid-onset bradycardia and decreased blood pressure in addition to central nervous system depression in 2 infants who received concomitant topical brimonidine and beta-blockers.

Administration, Topical↗
PubMed2003

Sustained raised intracranial pressure implicated only by pattern reversal visual evoked potentials after cranial vault expansion surgery.

Craniosynostosis, the premature fusion of cranial sutures, may be associated with raised intracranial pressure (ICP) with or without a reduced intracranial volume. Regardless of the aetiology, raised ICP may result in optic neuropathy, the timely detection of which can prevent further visual deterioration. Raised ICP is usually treated with craniofacial surgery such as cranial vault expansion. In this case study, we recorded serial pattern reversal visual evoked potentials (pVEPs) and obtained digital optic disc images before and after cranial vault expansion surgery. The amplitude of the pVEPs continued to decrease after cranial vault expansion surgery, prompting further neuroimaging that implicated a blocked ventriculo-peritoneal shunt. Only after shunt revision did the pVEP amplitude increase. Throughout the monitoring period, there was no change in the appearance of either the right or left optic disk, nor a consistent change in visual acuity.

Child↗
PubMed2002

Two-incision push-pull capsulorhexis for pediatric cataract surgery.

Pediatric capsulorhexis is a challenging surgical technique because of the elasticity of the pediatric anterior capsule. This technique of manual capsulorhexis allows reliable and reproducible results for the size and centration of anterior and posterior capsulorhexes in pediatric cases. The technique is a modification of a previously reported method.

Capsulorhexis↗
PubMedDate not supplied

The morphology and natural history of childhood cataracts.

The morphology of congenital cataract reflects a combination of the timing and nature of the cause, the anatomy of the lens including its capsule, its development, and changes that take place with time. Morphology may variably affect prognosis, give a clue to the etiology and the age of onset and, in an isolated case, sometimes suggest heritability. The spectrum of morphological variations is enormous and can be complex. A comprehensive approach is to classify the variations according to the area of the lens involved, and sub-dividing them by a detailed description of the shape and appearance. Each specific morphological type is then analyzed determining the etiology, visual prognosis, and management. The use of gene markers has allowed many of these variations to be identified and categorized. Cataracts in childhood can involve the whole lens, in which case they are called total, Morgagnian, or disk-like. They can affect only the center of the lens: lamellar, nuclear, oil droplet, cortical, or coronary. They can be anterior: anterior polar, anterior subcapsular, or anterior lenticonus. The posterior aspect of the lens can also be affected in different fashions: Mittendorf's dot, posterior lenticonus, posterior cortical cataracts, or posterior subcapsular. There are five more forms that must be described separately: punctuate lens opacities, sutural cataracts, coralliform or crystalline, wedge-shaped, and persistent hyperplastic primary vitreous.

Cataract↗