Search PubMed⌕ Search

Biomedical subjects

M O'Keefe

Publications and source records attributed to M O'Keefe.

At least 37 records · Page 2Linked to original sources
PubMed2001

Penetrating keratoplasty in infants.

PURPOSE: To analyze graft survival and visual outcome after penetrating keratoplasty in infants with congenital corneal opacity. METHODS: We retrospectively reviewed the records of 11 patients with congenital corneal opacity who underwent penetrating keratoplasty as infants. Six patients had a diagnosis of Peter's anomaly, 1 of congenital hereditary endothelial dystrophy, 1 of posterior polymorphous dystrophy, and 2 of sclerocornea, and in the other patient, the cause of the opacity was unknown. RESULTS: In total, 26 penetrating keratoplasties were performed on 16 eyes of 11 infants. All patients initially underwent surgery before the age of 13 months. Five patients underwent bilateral penetrating keratoplasty, and 10 of the transplants were repeat operations on eyes that had already had at least one previously failed graft. The age of the infants at the time of first penetrating keratoplasty ranged from 2 to 56 weeks (median, 13 weeks). The graft survival time for all transplants ranged from 3 to 137 months (median, 16 months). Overall first graft survival at 12 months was 61% (95% CI, 33%-81%), with 10 of 16 eyes retaining a clear corneal graft. Peter's anomaly, lensectomy, and repeat penetrating keratoplasty were factors most highly associated with poor graft survival and a low final visual acuity. CONCLUSION: Early penetrating keratoplasty for congenital corneal opacity may prevent deprivation amblyopia. Although this procedure carries a high risk of failure, particularly in those patients with Peter's anomaly, careful case selection, optical correction, and management of postoperative amblyopia may result in a successful visual outcome.

Adolescent↗
PubMed2001

Ocular findings among patients with late-diagnosed or poorly controlled homocystinuria compared with a screened, well-controlled population.

INTRODUCTION: Untreated homocystinuria (HCU) leads to systemic and ocular complications preventable by early treatment. METHODS: This study describes the ocular features in HCU patients who had late diagnosis or were noncompliant with treatment compared with a control group of early-diagnosed and well-controlled subjects. RESULTS: Fourteen late-diagnosed HCU patients with a median age at diagnosis of 4 years (range, 1.25-28 years) were studied. Five patients were born outside of Ireland or before screening began. All 14 patients had lens subluxation or dislocation at diagnosis. Only 28.6% of eyes had 20/40 vision or better. Three patients were tested for HCU following the diagnosis in a sibling. Four patients attended ophthalmology departments for a median of 12.8 years (range, 4-23 years) prior to diagnosis of HCU; all had steadily progressive myopic astigmatism and lens subluxation. Six patients who became poorly controlled in their teens or early twenties showed significant progression of their myopia, and 3 had phacodonesis or lens subluxation develop. All eyes in this group had 20/40 vision or better. Fifteen patients who were detected in the newborn period and remained well controlled had no evidence of lens subluxation. All of the control group patients had 20/20 vision bilaterally. The difference in visual acuity between late-diagnosed patients and the control group was highly significant (P =.0002). The differences in refractive errors between the groups were also highly significant (P =.0001). CONCLUSIONS: Lens subluxation is a principal feature of untreated HCU, yet we found a median lag period of 5.5 years in 4 cases before diagnosis. Young persons with marked and progressive myopia or idiopathic lens subluxation should be screened for HCU.

Adult↗
PubMed2001

Temperature-modulated array high-performance liquid chromatography.

Using novel monolithic poly(styrene-divinylbenzene) capillary columns with an internal diameter of 0.2 mm, we demonstrate for the first time the feasibility of constructing high-performance liquid chromatography arrays for the detection of mutations by heteroduplex analysis under partially denaturing conditions. In one embodiment, such an array can be used to analyze one sample simultaneously at different temperatures to maximize the detection of mutations in DNA fragments containing multiple discrete melting domains. Alternatively, one may inject different samples onto columns kept at the same effective temperature. Further improvements in throughput can be obtained by means of laser-induced fluorescence detection and the differential labeling of samples with up to four different fluorophores. Major advantages of monolithic capillary high-performance liquid chromatographic arrays over their capillary electrophoretic analogs are the chemical inertness of the poly(styrene-divinylbenzene) stationary phase, the physical robustness of the column bed due to its covalent linkage to the inner surface of the fused silica capillary, and the feasibility to modify the stationary phase thereby allowing the separation of compounds not only on the principle of size exclusion, but also adsorption, distribution, and ion exchange. Analyses times are on the order of a few minutes and turnaround time is extremely short as there is no need for the replenishment of the separation matrix between runs.

Chromatography, High Pressure Liquid↗
PubMed2001

A method for parallel, automated, thermal cycling of submicroliter samples.

A large fraction of the cost of DNA sequencing and other DNA-analysis processes results from the reagent costs incurred during cycle sequencing or PCR. In particular, the high cost of the enzymes and dyes used in these processes often results in thermal cycling costs exceeding $0.50 per sample. In the case of high-throughput DNA sequencing, this is a significant and unnecessary expense. Improved detection efficiency of new sequencing instrumentation allows the reaction volumes for cycle sequencing to be scaled down to one-tenth of presently used volumes, resulting in at least a 10-fold decrease in the cost of this process. However, commercially available thermal cyclers and automated reaction setup devices have inherent design limitations which make handling volumes of <1 microL extremely difficult. In this paper, we describe a method for thermal cycling aimed at reliable, automated cycling of submicroliter reaction volumes.

Microchemistry↗
PubMed2001

Ocular significance of intraventricular haemorrhage in premature infants.

AIM: To document ocular outcome in premature infants with intraventricular haemorrhages (IVH). METHODS: 68 preterm infants with IVH were examined. RESULTS: Mean gestational age was 28.1 weeks (range 24-35). Mean birth weight was 1045.9 g (630-2240). Mean follow up was 54.6 months (6-150). IVH is graded from 1 to 4 based on the severity of haemorrhages. The incidence of ocular abnormalities was compared between low grade IVH (grade 1 and 2) and high grade IVH (grade 3 and 4). Of the 68 infants with IVH, ROP occurred in 33 infants (48.5%); 13 (43.3%) had low grade IVH; 20 (52.6%) had high grade IVH. Strabismus developed in 30 infants (44.1%); 14 (46.6%) had low grade IVH; 16 (42.1%) had high grade IVH. Infants with high grade IVH were at significant greater risk than infants with low grade IVH for the development of optic atrophy (31.5% v 16.6%), hydrocephalus (57.8% v 10%). CONCLUSION: This study highlights the serious significance of all grades of IVH with the higher incidence of optic atrophy and hydrocephalus with high grade IVH.

Cerebral Hemorrhage↗
PubMed2001

Troglitazone improves ovulation and hirsutism in the polycystic ovary syndrome: a multicenter, double blind, placebo-controlled trial.

We hypothesized that the administration of troglitazone, an insulin-sensitizing agent of the thiazolidinedione class, would improve the ovulatory dysfunction, hirsutism, hyperandrogenemia, and hyperinsulinemia of polycystic ovary syndrome (PCOS) patients. Four hundred and ten premenopausal women with PCOS in a multicenter, double blind trial were randomly assigned to 44 weeks of treatment with placebo (PBO) or troglitazone [150 mg/day (TGZ-150), 300 mg/day (TGZ-300), or 600 mg/day (TGZ-600)]. We compared changes in ovulatory function (by monitoring the urinary level of pregnanediol-3-glucuronide daily), hirsutism (by a modified Ferriman-Gallwey scoring method), hormonal levels (total and free testosterone, androstenedione, sex hormone-binding globulin, LH, FSH, and the LH/FSH ratio), and measures of glycemic parameters (fasting levels of glucose, insulin, hemoglobin A(1c), and the glucose and insulin areas under the curve during an oral glucose challenge) among study groups. Of the 410 patients recruited, 305 (74.4%) met evaluability criteria and were included in the analyses. The patients' baseline characteristics were similar across all treatment arms. Ovulatory rates were significantly greater for patients receiving TGZ-300 and TGZ-600 than for those receiving PBO (0.42 and 0.58 vs. 0.32; P < 0.05 and 0.0001, respectively). Of PCOS patients treated with TGZ-600, 57% ovulated over 50% of the time compared with 12% of placebo-treated patients. There was a significant decrease in the Ferriman-Gallwey score with TGZ-600 compared with PBO (0.22 +/- 0.53 vs. -2.21 +/- 0.49; P < 0.05, respectively). Free testosterone decreased and sex hormone-binding globulin increased in a dose-related fashion with troglitazone treatment, and all three troglitazone treatment groups were significantly different from placebo. Nearly all glycemic parameters showed dose-related decreases with troglitazone treatment. The total number and severity of adverse events (including elevations in liver enzymes) and the proportion of patients withdrawn from the study due to the development of adverse effects were similar between treatment groups. Troglitazone improves the ovulatory dysfunction, hirsutism, hyperandrogenemia, and insulin resistance of PCOS in a dose-related fashion, with a minimum of adverse effects.

Adult↗
PubMed2000

Visual outcome and complications of bilateral intraocular lens implantation in children.

PURPOSE: To determine the safety and efficacy of bilateral intraocular lens (IOL) implantation in children. SETTING: Tertiary referral pediatric ophthalmology department. METHODS: This retrospective study comprised 13 children (26 eyes) who had bilateral cataract surgery with IOL implantation. Patients were divided into 2 groups: congenital cases, diagnosed during the first year of life, and developmental cases, diagnosed after 1 year of age. All patients had small incision phacoemulsification with primary implantation of a poly(methyl methacrylate) or a foldable acrylic IOL. Primary posterior capsulotomy was performed in 16 eyes (61.5%). RESULTS: Age at surgery ranged from 1 week to just under 8 years. Seven patients (53.8%) had a systemic diagnosis: Down's syndrome (n = 4); developmental delay or cerebral atrophy (n = 3). Five children with systemic problems could not cooperate with formal vision testing; 2 could fix and follow bilaterally, and 3 had central, steady, and maintained vision bilaterally. In the congenital group, 37.5% of eyes attained a visual acuity of 20/20 and 87.5%, 20/120 or better. In the developmental group, formal vision testing was possible in 4 children. Five eyes (83.3%) attained a visual acuity of 20/40 or better. Thirteen eyes (50.0%) required posterior capsulotomy. Primary posterior capsulotomy reduced the incidence of posterior capsule opacification (PCO), but there was no correlation between PCO and IOL material. One patient developed glaucoma bilaterally. CONCLUSION: Bilateral IOL implantation was safe and produced good visual results in children of all ages with bilateral cataract.

Acrylic Resins↗
PubMed2000

Paediatric laser DCR.

PURPOSE: Endoscopic laser dacrocystorhinostomy is an alternative procedure to external approach DCR in children. We report our results with 5 patients (6 eyes) with congenital nasolacrimal duct obstruction. METHODS: Six endonasal DCR's were carried out using the KTP laser in patients with congenital nasolacrimal duct obstruction resistant to probing and intubation. RESULTS: The follow-up ranged from 3-8 months. All patients experienced a recurrence of their symptoms postoperatively. CONCLUSION: Endoscopic laser assisted DCR is not a successful procedure in children.

Child↗
PubMed2000

Outcome in refractive accommodative esotropia.

AIM: To examine outcome among children with refractive accommodative esotropia. METHODS: Children with accommodative esotropia associated with hyperopia were included in the study. The features studied were ocular alignment, amblyopia, and the response to treatment, binocular single vision, requirement for surgery, and the change in refraction with age. RESULTS: 103 children with refractive accommodative esotropia were identified. Mean follow up was 4.5 years (range 2-9.5 years). 41 children (39.8%) were fully accommodative (no manifest deviation with full hyperopic correction). The remaining 62 children (60.2%) were partially accommodative. At presentation 61.2% of children were amblyopic in one eye decreasing to 15.5% at the most recent examination. Stereopsis was demonstrated in 89.3% of children at the most recent examination. Mean cycloplegic refraction (dioptres, spherical equivalent) remained stable throughout the follow up period. The mean change in refraction per year was 0.005 dioptres (D) in right eyes (95% CL -0. 0098 to 0.02) and 0.001 D in left eyes (95% CL -0.018 to 0.021). No patients were able to discard their glasses and maintain alignment. CONCLUSIONS: Most children with refractive accommodative esotropia have an excellent outcome in terms of visual acuity and binocular single vision. Current management strategies for this condition result in a marked reduction in the prevalence of amblyopia compared with the prevalence at presentation. The degree of hyperopia, however, remains unchanged with poor prospects for discontinuing glasses wear. The possibility that long term full time glasses wear impedes emmetropisation must be considered. It is also conceivable, however, that these children may behave differently with normal and be predestined to remain hyperopic.

Amblyopia↗
PubMed1999

Primary posterior capsulorhexis without anterior vitrectomy in pediatric cataract surgery: longer-term outcome.

PURPOSE: To assess the effectiveness of primary posterior capsulorhexis without anterior vitrectomy in preventing posterior capsule opacification (PCO) in pediatric cataract surgery. SETTING: Children's Hospital, Dublin, Republic of Ireland. METHODS: The study comprised 32 eyes of 22 pediatric patients who had cataract extraction between 1994 and 1998. Extracapsular cataract extraction was performed using radiofrequency diathermy capsulorhexis to the anterior and posterior capsules without an anterior vitrectomy. Posterior chamber intraocular lens implantation was performed in 20 eyes. There were 23 congenital, 6 developmental, and 3 traumatic cataracts. RESULTS: Patient age ranged from 1 month to 12 years. Mean follow-up was 19 months (range 6 to 50 months). Twenty-seven of 32 eyes (84.4%) had a clear visual axis at last follow-up. Five eyes required a neodymium: YAG capsulotomy, which was performed a mean of 5 months postoperatively (range 1 to 9 months). The incidence of PCO requiring capsulotomy was 15.6%. CONCLUSION: Primary posterior capsulorhexis without anterior vitrectomy was safe and effective, with a low reopacification rate. Long-term follow-up of this patient cohort is necessary.

Anterior Eye Segment↗
PubMed1999

Long-term outcome of epikeratophakia.

PURPOSE: To assess the long-term outcome of epikeratophakia. SETTING: National center for pediatric ophthalmology (The Children's Hospital) and ophthalmology department in a regional general hospital (Waterford Regional Hospital), Republic of Ireland. METHODS: A retrospective clinical review was carried out of 25 eyes (20 patients) with epikeratophakia performed over 10 years. Eyes were assigned to a children's group (Group 1) or an adult group (Group 2), depending on patient age at the time of surgery, and assessed with respect to indication for surgery, visual acuity, condition of the implanted lenticule, complications, refraction, and corneal topography. Histological analysis was performed on 1 removed lenticule. RESULTS: Mean follow-up of all patients was 7.3 years (median 6.8 years; range 4.0 to 10.0 years). Most eyes (n = 18) were contact lens intolerant. Freeze-dried lenticules were implanted in all cases, and all but 1 had stable visual acuity from the early postoperative period to last follow-up. In Group 1 (n = 10), most eyes had a visual acuity of 6/36 or worse preoperatively with an improvement of 1 or more lines in 4 eyes. In Group 2 (n = 14), at last follow-up most eyes retained good or improved visual acuity by 1 or more lines. Most grafts were clear or had insignificant opacities outside the visual axis. The overall complication rate was 12%, with the most serious complication being significant induced astigmatism requiring removal of 1 epigraft. Mean induced astigmatism was 2.50 diopters (D) (median 2.00 D; range 1.00 to 6.00 D), which was accurately predicted within +/- 1.00 D by corneal topography in 14 of 19 eyes. Histology demonstrated infiltration of the implanted lenticule by host keratocytes. CONCLUSION: Epikeratophakia, a reversible procedure with a low complication rate, resulted in stable visual acuity with good lenticule condition and minimal induced regular astigmatism after long-term follow-up.

Adolescent↗
PubMed1999

Intraocular lenses in children: changes in axial length, corneal curvature, and refraction.

AIM: To assess changes in axial length, corneal curvature, and refraction in paediatric pseudophakia. METHODS: 35 eyes of 24 patients with congenital or developmental lens opacities underwent extracapsular cataract extraction and posterior chamber intraocular lens implantation. Serial measurements were made of axial length, corneal curvature, objective refraction, and visual acuity. RESULTS: For patients with congenital cataracts (onset < 1 year age) the mean age at surgery was 24 weeks. Over the mean follow up period of 2.7 years, the mean increase in axial length of 3.41 mm was not significantly different from the value of an expected mean growth of 3.44 mm (paired t test, p = 0.97) after correction for gestational age. In the developmental cataract group (onset > 1 year of age) the mean age at surgery was 6.4 years with a mean follow up of 2.86 years. This group showed a mean growth in axial length of 0.36 mm that was not significantly different from an expected value of 0.47 mm (paired t test, p = 0.63). The mean preoperative keratometry was 47.78 D in the congenital group and 44.35 D in the developmental group. At final follow up the mean keratometry in the congenital group was 46.15 D and in the developmental group it was 43.63 D. In eyes followed for at least 2 years, there was an observed myopic shift by 24 months postoperatively of 3.26 D in the congenital cases (n = 10) and 0.96 D in the developmental cases (n = 18). CONCLUSION: The pattern of axial elongation and corneal flattening was similar in the congenital and developmental groups to that observed in normal eyes. No significant retardation or acceleration of axial growth was found in the eyes implanted with IOLs compared with normal eyes. A myopic shift was seen particularly in eyes operated on at 4-8 weeks of age and it is recommended that these eyes are made 6 D hypermetropic initially with the residual refractive error being corrected with spectacles.

Cataract↗