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Biomedical subjects

G E Quinn

Publications and source records attributed to G E Quinn.

At least 19 recordsLinked to original sources
PubMed2001

The amblyopia treatment study visual acuity testing protocol.

OBJECTIVE: To evaluate the reliability of a new visual acuity testing protocol for children using isolated surrounded HOTV optotypes. METHODS: After initial pilot testing and modification, the protocol was evaluated using the Baylor-Video Acuity Tester (BVAT) to present isolated surrounded HOTV optotypes. At 6 sites, the protocol was evaluated for testability in 178 children aged 2 to 7 years and for reliability in a subset of 88 children. Twenty-eight percent of the 178 children were classified as having amblyopia. RESULTS: Using the modified protocol, testability ranged from 24% in 2-year-olds to 96% in 5- to 7-year-olds. Test-retest reliability was high (r = 0.82), with 93% of retest scores within 0.1 logMAR unit of the initial test score. The 95% confidence interval for an acuity score was calculated to be the score +/-0.125 logMAR unit. For a change between 2 acuity scores, the 95% confidence interval was the difference +/-0.18 logMAR unit. CONCLUSIONS: The visual acuity protocol had a high level of testability in 3- to 7-year-olds and excellent test-retest reliability. The protocol has been incorporated into the multicenter Amblyopia Treatment Study and has wide potential application for standardizing visual acuity testing in children.

Amblyopia↗
PubMed2001

Does cryotherapy affect refractive error? Results from treated versus control eyes in the cryotherapy for retinopathy of prematurity trial.

PURPOSE: To evaluate the effect of cryotherapy on refractive error status between ages 3 months and 10 years in children with birth weights of less than 1251 g in whom severe retinopathy of prematurity (ROP) developed in one or both eyes during the neonatal period. DESIGN: Randomized clinical trial. PARTICIPANTS: Two hundred ninety-one children in whom severe ROP developed during the neonatal period. INTERVENTION: Cryotherapy for ROP. MAIN OUTCOME MEASURES: Cycloplegic Refraction METHODS: The children underwent repeated follow-up eye examinations, including cycloplegic retinoscopy, between 3 months and 10 years after term due date. Refractive error data from all eyes that were randomized to cryotherapy were compared with data from all eyes that were randomized to serve as controls. Refractive error data were also compared for a subset of children who had both a treated and a control eye that could be refracted. RESULTS: At all ages, the proportion of treated eyes that were unable to be refracted because of retinal detachment, media opacity, or pupillary miosis was approximately half the proportion of the control eyes that were unable to be refracted. When data from all eyes that could be refracted were considered, the distribution of refractive errors between fewer than 8 diopters (D) of myopia and more than 8 D of hyperopia was similar for treated and control eyes at all ages. The proportion of eyes with 8 D or more of myopia was much higher in treated than in control eyes at all ages after 3 months. In the subset of children who had a treated eye and a control eye that could be refracted, distributions of refractive errors in treated versus control eyes were similar at most ages. CONCLUSIONS: In both treated and control eyes, there was an increase in the prevalence of high myopia between 3 and 12 months of age. Between 12 months and 10 years of age, there was little change in distribution of refractive error in treated or control eyes. The higher prevalence of myopia of 8 D or more in treated eyes, as compared with control eyes, may be the result of cryotherapy's preservation of retinal structure in eyes that, in the absence of cryotherapy, would have progressed to retinal detachment.

Astigmatism↗
PubMed2000

Severity of neonatal retinopathy of prematurity is predictive of neurodevelopmental functional outcome at age 5.5 years. Behalf of the Cryotherapy for Retinopathy of Prematurity Cooperative Group.

OBJECTIVE: The purpose of this study was to assess the relation between neonatal retinopathy of prematurity (ROP) in very low birth weight infants and neurodevelopmental function at age 5.5 years. METHODS: Longitudinal follow-up of children occurred in 2 cohorts of the Multicenter Cryotherapy for Retinopathy of Prematurity Study. The extended natural history cohort followed 1199 survivors of <1251 g birth weight from 5 centers. The threshold randomized cohort (ThRz) followed 255 infants <1251 g from 23 centers who developed threshold ROP and who consented to cryotherapy to not more than 1 eye. At 5.5 years both cohorts had ophthalmic and acuity testing and neurodevelopmental functional status determined with the Functional Independence Measure for Children (WeeFIM). RESULTS: Evaluations were completed on 88.7% of the extended natural history cohort; 87% had globally normal functional skills (WeeFIM: >95). As ROP severity increased, rates of severe disability increased from 3.7% among those with no ROP, to 19.7% of those with threshold ROP. Multiple logistic regression analysis demonstrated that better functional status was associated with favorable visual acuity, favorable 2-year neurological score, absence of threshold ROP, having private health insurance, and black race. Evaluations were completed on 87.4% of the ThRz children. In each functional domain, the 134 children with favorable acuity in their better eye had fewer disabilities than did the 82 children with unfavorable acuity: self-care disability 25.4% versus 76.8%, continency disability 4.5% versus 50.0%, motor disability 5.2% versus 42.7%, and communicative-social cognitive disability 22.4% versus 65.9%, respectively. CONCLUSION: Severity of neonatal ROP seems to be a marker for functional disability at age 5. 5 years among very low birth weight survivors. High rates of functional limitations in multiple domains occur in children who had threshold ROP, particularly if they have unfavorable visual acuity.

Child, Preschool↗
PubMed1999

Distance and near visual acuity, contrast sensitivity, and visual fields of 10-year-old children.

OBJECTIVE: To measure monocular distance visual acuity, near visual acuity, contrast sensitivity, and visual field extent in full-term, 10-year-old children tested according to the protocol used to test 10-year-old preterm children in the Cryotherapy for Retinopathy of Prematurity study. SUBJECTS AND METHODS: Subjects were 106 healthy, full-term children, 9.8 to 10.9 years of age, who had no ocular abnormalities other than ametropia. All were tested monocularly using Early Treatment and Diabetic Retinopathy Study distance and near visual acuity charts and Pelli-Robson contrast sensitivity charts, with refractive error corrected according to Cryotherapy for Retinopathy of Prematurity study criteria. Goldmann perimetry was tested without correction using the V-4-e and III-4-e stimuli along 8 meridia. A standard pediatric eye examination was performed on each subject. RESULTS: Mean (SD) distance visual acuity was 20/19.6 OD (0.082 log unit [lu]) and mean near visual acuity was 20/19.5 OD (0.100 lu). Mean (SD) contrast sensitivity was 1.69 OD (0.12 lu), with a mean (SD) of 36.4 (2.2) letters read. Visual field extent was larger for the V-4-e stimulus than for the III-4-e stimulus. CONCLUSIONS: The results provide the first monocular normative data from a large sample of 10-year-old children tested with Early Treatment and Diabetic Retinopathy Study distance and near visual acuity charts and the Pelli-Robson contrast sensitivity charts, and add to the literature on Goldmann perimetry in children.

Child↗
PubMed1999

Interobserver agreement for grating acuity and letter acuity assessment in 1- to 5.5-year-olds with severe retinopathy of prematurity.

PURPOSE: To evaluate interobserver test-retest reliability of the Teller Acuity Card procedure for assessment of grating acuity at ages 1, 2, 3.5, 4.5, and 5.5 years, for HOTV letter acuity at 3.5 and 4.5 years, and for Early-Treatment Diabetic Retinopathy Study (ETDRS) letter acuity at 5.5 years in the multicenter study of Cryotherapy for Retinopathy of Prematurity (CRYO-ROP). METHODS: Subjects were the 73 participants in the CRYO-ROP study who had acuity assessed at one or more ages by two of the seven study visual acuity testers as part of a quality control procedure. All subjects had birth weights of less than 1251 g, and all had severe (threshold) ROP in one or both eyes. RESULTS: For sighted eyes, interobserver agreement for grating acuity (across all five test ages) was 0.5 octave or better in 57% of eyes and 1.0 octave or better in 85% of eyes. Interobserver agreement for letter acuity (3.5-, 4.5-, and 5.5-year test ages) was 0.5 octave or better in 71% of eyes and 1.0 octave or better in 93% of eyes. For all eyes (sighted and blind), Kendall rank correlation coefficients (Tau) were 0.86, 0.83, and 0.94 for grating, HOTV, and ETDRS acuity, respectively. Kappa statistics on data from all eyes indicated excellent interobserver agreement for grating, HOTV, and ETDRS acuity (0.73, 0.80, and 0.84, respectively). Interobserver agreement was not related to age or to severity of retinal residua of ROP. CONCLUSIONS: Excellent interobserver agreement for grating acuity measurements and for letter acuity measurements was obtained. Results suggest that with careful training and implementation of quality control procedures, high reliability of visual acuity results is possible in clinical populations of young children.

Child↗
PubMed1999

Agreement between grating acuity at age 1 year and Snellen acuity at age 5.5 years in the preterm child. Cryotherapy for Retinopathy of Prematurity Cooperative Group.

PURPOSE: To examine the relation between grating acuity at age 1 year and Snellen acuity and grating acuity at 5.5 years, in preterm children with birth weights less than 1251 g. METHODS: Subjects were participants in the multicenter study of Cryotherapy for Retinopathy of Prematurity. The Teller acuity card (TAC; Vistech Consultants, Dayton, OH) procedure was used to measure monocular grating acuity in children at ages 1 and 5.5 years. Early-treatment diabetic retinopathy study (ETDRS) charts were used to measure the childrens' monocular recognition (Snellen) acuity at age 5.5 years. Data are presented for 575 eyes with measurable TAC grating acuity at 1 year and 111 eyes that had no measurable acuity at 1 year. RESULTS: Among eyes with normal acuity at 1 year, 86.8% showed normal Snellen acuity, and 94.3% showed normal grating acuity at 5.5 years. Among eyes that were blind (i.e., had no measurable TAC grating acuity) at 1 year, 96.8% showed no quantifiable Snellen acuity, and 89.2% showed no quantifiable grating acuity at 5.5 years. Only 2.4% of eyes had acuity in the range between normal and blind at 1 year (i.e., measurable grating acuity <1.6 cyc/deg); thus, the predictive value of acuity scores in this range could not be determined. Correlation analysis indicated that the relative position within the normal range of an eye's grating acuity score at 1 year was not predictive of the relative position within the normal range of that eye's acuity score at 5.5 years. CONCLUSIONS: Among a large population of low-birth-weight infants, eyes with normal grating acuity at age 1 year generally showed normal Snellen and grating acuity at age 5.5 years, and eyes that had no quantifiable acuity at 1 year remained blind at 5.5 years. Relative position of an eye's acuity score within the normal range was not predictive of the relative position of that eye's later acuity score.

Blindness↗
PubMed1998

Prevalence of myopia between 3 months and 5 1/2 years in preterm infants with and without retinopathy of prematurity. Cryotherapy for Retinopathy of Prematurity Cooperative Group.

PURPOSE: The purpose of the study was to examine spherical equivalent refractive errors, especially myopia, at six ages between 3 months and 5 1/2 years post-term in preterm children with birth weights of less than 1251 g. DESIGN: A cohort study. PARTICIPANTS: There were a total of 827 participants in the multicenter study of cryotherapy for retinopathy of prematurity (ROP). Approximately one third of the eyes did not develop ROP, whereas two thirds developed mild-to-severe ROP. None of the eyes underwent cryotherapy. INTERVENTION: Refractive error was measured at 3 months, 1 year, and 5 1/2 years term due date at the five long-term follow-up centers. In most eyes, refractive error also was measured at 2, 3 1/2, and 4 1/2 years. MAIN OUTCOME MEASURE: Myopia was defined as 0.25 diopter (D) or greater with high myopia as 5 D or greater. RESULTS: The proportion of eyes with myopia in this preterm population was increased compared to published data on full-term children and was related to severity of both acute-phase and cicatricial-phase ROP. The percentage of eyes with myopia varied little across ages, ranging from 21.2% at 1 year to 15.7% at 4 1/2 years. The percentage of eyes with high myopia doubled from 1.8% to 3.9% between 3 months and 1 year and remained stable thereafter. The distribution of refractive errors in eyes with mild acute-phase ROP was similar to that of eyes with no ROP. In contrast, eyes with moderate or severe acute-phase ROP showed an increased prevalence of high myopia. The distribution of refractive errors changed between 3 months and 1 year with little change after 1 year. This pattern of refractive development differs from that of full-term infants. Birth weight, severity of ROP, and degree of myopia at 3 months predicted the presence of myopia and high myopia at 5 1/2 years of age. CONCLUSIONS: The distribution of refractive errors in preterm infants from age 3 months to 5 1/2 years varies with severity of acute-phase ROP and cicatricial disease. Changes in refractive error distribution occur primarily between 3 months and 1 year and involve a decrease in the proportion of eyes with hyperopia and an increase in the proportion with high degrees of myopia.

Acute Disease↗
PubMed1998

OA1 mutations and deletions in X-linked ocular albinism.

X-linked ocular albinism (OA1), Nettleship-Falls type, is characterized by decreased ocular pigmentation, foveal hypoplasia, nystagmus, photodysphoria, and reduced visual acuity. Affected males usually demonstrate melanin macroglobules on skin biopsy. We now report results of deletion and mutation screening of the full-length OA1 gene in 29 unrelated North American and Australian X-linked ocular albinism (OA) probands, including five with additional, nonocular phenotypic abnormalities (Schnur et al. 1994). We detected 13 intragenic gene deletions, including 3 of exon 1, 2 of exon 2, 2 of exon 4, and 6 others, which span exons 2-8. Eight new missense mutations were identified, which cluster within exons 1, 2, 3, and 6 in conserved and/or putative transmembrane domains of the protein. There was also a splice acceptor-site mutation, a nonsense mutation, a single base deletion, and a previously reported 17-bp exon 1 deletion. All patients with nonocular phenotypic abnormalities had detectable mutations. In summary, 26 (approximately 90%) of 29 probands had detectable alterations of OA1, thus confirming that OA1 is the major locus for X-linked OA.

Albinism, Ocular↗
PubMed1998

Variability in visual cortex activation during prolonged functional magnetic resonance imaging.

This study was conducted to test whether cortical activation varies across successive epoques during functional magnetic resonance imaging (fMRI) studies. Ten normal adult volunteers were studied with a 1.5-T MR scanner. Pseudocoronal study planes were chosen perpendicular to the tentorium cerebelli, at two thirds the distance from the posterior edge of the splenium of the corpus callosum to the transverse sinuses. Functional images were acquired with a T2*-weighted spoiled gradient echo sequence. The visual cortex was stimulated by goggles flashing at 8 Hz. Each study consisted of 82 sequential scans, lasting 15 seconds each for a total of 20.5 minutes. Two scans without stimulation were alternated with two scans of visual stimulation. Scans 3 through 83 were divided into five sequences of 16 scans. For each sequence, the number of pixels within a predefined rectangular region of interest that showed increased activity during stimulation were counted. Least squares regression models of straight lines were fit to the data. The initial level of visual cortex activation in the region of interest, as measured by the y-intercept, varied substantially from subject to subject (range: 4-68, p < 0.001). There was sufficient evidence of systematic change with time to reject the hypothesis of constant activation with the same stimulus over time (p=0.02). The observed visual cortex activation with single-plane fMRI varied both with time over successive epoques and among subjects. Possible factors responsible for the variation may include head movement, eyelid position, attention, and physiologic fatigue. These factors must be accounted for in experimental design and in data analysis and interpretation.

Adult↗
PubMed1997

Vitamin E prophylaxis to reduce retinopathy of prematurity: a reappraisal of published trials.

OBJECTIVE: We conducted a meta-analysis of the published randomized clinical trials of vitamin E prophylaxis designed to reduce retinopathy of prematurity (ROP) to determine whether increased serum concentrations of vitamin E reduced the incidence of severe, threshold (Stage 3+) ROP in the very low birth weight (VLBW) infant subset. STUDY DESIGN: Among the six trials considered eligible for analyses, the incidence for all stages of ROP and for Stage 3+ ROP was computed for all randomly assigned infants (intention-to-treat analysis) and for those infants completing the trials. Odds ratios (ORs) and pooled estimates for event rate reductions (and the respective 95% confidence intervals [CIs]) were calculated for these outcome end points. RESULTS: There were 704 VLBW infants in the vitamin E prophylaxis groups and 714 in control groups; 536 (76.1%) infants in the vitamin E and 551 (77.2%) in the control groups completed the trials. In all trials the mean serum vitamin E concentrations were within or above the physiologic range in the vitamin-treated groups and at or below the physiologic ranges in the control groups. The overall incidence of any stage ROP was similar between the groups: 39.8% in the vitamin E group and 43.5% in the control group. The overall incidence for Stage 3+ ROP was lower in the vitamin E-treated groups than in the control group (2.4% in vitamin E vs 5.3% in control). The pooled OR for developing Stage 3+ ROP with vitamin E prophylaxis was 0.44 (95% CI, 0.21, 0.81, p < 0.02). The reciprocal of the pooled estimate of mean risk reduction (2.8%, 95% CI: 0.55%, 5.1%) for Stage 3+ ROP revealed that on average, vitamin E prophylaxis given to 35 VLBW infants would prevent one case of threshold, Stage 3+ ROP. CONCLUSIONS: Considering that there was a 52% reduction in the incidence of Stage 3+ ROP, we suggest that the role of vitamin E in reducing severe ROP be re-evaluated. We could not assess the adverse effect rates from vitamin E therapy in the trials analyzed; therefore, we recommend a well-controlled and focused trial in which the issues of benefit, adverse effects, and cost can be assessed with vitamin E prophylaxis in extremely low birth weight (< 1000 gm) infants.

Confidence Intervals↗
PubMed1997

Extracorporeal membrane oxygenation causing asymmetric vasculopathy in neonatal infants.

BACKGROUND: Extracorporeal membrane oxygenation (ECMO) is a form of cardiopulmonary bypass therapy used in term or near-term infants with severe cardiorespiratory disorders not responsive to conventional intensive care interventions. An ECMO-associated retinal vasculopathy has been described with little reference to the specific condition of the patient. We examined the eyes of 91 infants who underwent ECMO treatment. An assessment was made of the following: (1) when retinal changes occurred, (2) whether there was a particular systemic disorder or ECMO approach associated with these retinal findings, and (3) whether there may be ocular sequelae from this development. METHODS: Ninety-one neonates were treated with ECMO for meconium aspiration syndrome (MAS), primary persistent pulmonary hypertension of the newborn, sepsis, congenital diaphragmatic hernia (CDH), respiratory distress syndrome (RDS), and blood aspiration. Venoarterial bypass was performed in 73 patients. The remaining 18 patients underwent venovenous bypass. Ophthalmologic examinations were performed during bypass in 6 infants and within 3 weeks of ECMO in the remainder. RESULTS: Asymmetric retinopathy (left eye > right eye) was discovered in six infants with CDH and in one infant with RDS within a 2-week period after bypass, demonstrating venous tortuosity with or without intraretinal hemorrhages. One infant treated for MAS had a left eye intraretinal hemorrhage only. All patients with the noted retinal changes underwent venoarterial cannulation. Six of 9 patients with CDH had retinal findings noted compared with 1 of 10 patients with RDS and 1 of 35 patients with MAS. CONCLUSION: Because we were able to examine infants while they were receiving ECMO or shortly after termination of bypass, asymmetric vasculopathy was found in a greater percentage of our patients compared with a similar large case series. ECMO-associated retinal vasculopathy appeared to disproportionately occur in those patients with CDH who underwent venoarterial bypass. Further study of retinal vascular changes in patients with CDH should be performed to assess long-term effects.

Extracorporeal Membrane Oxygenation↗
PubMed1997

Comitant esodeviation resulting from neurologic insult in children.

PURPOSE: Our purpose was to establish whether comitance was a common or uncommon finding in children with esodeviation associated with a neurologic insult. METHODS: A retrospective chart review was performed of children with acquired esodeviation associated with an identifiable neurologic insult. RESULTS: Examinations of 30 children seen over a 2-year period were analyzed. Twenty-two (73%) had brain tumors. Twelve (40%) had comitant esodeviation, and the other 18 (60%) had incomitant measurements. Of the patients with comitant esodeviation, 6 had normal abduction OU (two after recovery from bilateral sixth nerve palsies), and 6 had mild or minimal abduction deficits. Moderate or severe abduction deficits were associated with incomitant measurements. CONCLUSIONS: Comitant esodeviation can be common in children with identifiable neurologic insults.

Accommodation, Ocular↗
PubMed1996

Measurement of Goldmann visual fields in older children who received cryotherapy as infants for threshold retinopathy of prematurity.

BACKGROUND: Cryotherapy administered to eyes with severe acute-phase (threshold) retinopathy of prematurity benefits retinal structure and visual acuity compared with the natural course of the retinopathy. OBJECTIVES: To determine the extent of peripheral field abnormalities in eyes with threshold retinopathy of prematurity that had retinal structure preserved by cryotherapy. METHODS: Kinetic perimetry was performed with a Goldmann perimeter by masked testers on patients in whom bilateral threshold retinopathy of prematurity developed and who had been randomly assigned to undergo cryotherapy in one eye and no cryotherapy in the fellow eye. With the V-4-e and the II-4-e targets, eight meridians were tested: 0 degrees, 45 degrees, 90 degrees, 135 degrees, 180 degrees, 225 degrees, 270 degrees, and 315 degrees. The median value of three presentations in each meridian was accepted as the extent in that meridian. RESULTS: Fourteen eyes (eight treated and six control) of eight patients (mean age, 9.9 years; range, 6 to 11 years) had adequate vision to undergo fields testing. Mean (+/-SE) extent of visual field for treated vs control eyes was 36 degrees +/- 3 degrees vs 46 degrees +/- 6 degrees for the II-4-e target and 49 degrees +/- 4 degrees vs 59 degrees +/- 6 degrees for the V-4-e target. This difference was consistent across all eight meridians for either target, and repeated-measures analysis of variance showed that cryotherapy was associated with smaller visual field extent for both target sizes (P=.08). CONCLUSION: The results of this small pilot study suggest that eyes that have retinal structure and acuity preserved by cryotherapy for severe acute-phase retinopathy of prematurity have slightly smaller visual fields than untreated eyes with severe acute-phase retinopathy of prematurity that had vision preserved.

Acute Disease↗