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Biomedical subjects

E A Palmer

Publications and source records attributed to E A Palmer.

At least 19 recordsLinked to original sources
PubMed1998

Strabismus in premature infants in the first year of life. Cryotherapy for Retinopathy of Prematurity Cooperative Group.

OBJECTIVES: To present the 3- and 12-month strabismus data from 3030 premature infants with birth weights less than 1251 g enrolled in the Multicenter Trial of Cryotherapy for Retinopathy of Prematurity. DESIGN: Data from the 3- and 12-month examinations conducted at 23 regional study centers were tabulated for all infants. The main outcome measure, ocular motility, was compared with baseline demographic variables and retinopathy of prematurity severity for the worse eye. Findings at 3 months were compared with the incidence of strabismus at 12 months. RESULTS: At 3 months, 200 (6.6%) of the 3030 infants were strabismic. In the 2449 infants examined at both time points, 289 (11.8%) were found to have strabismus at 12 months. Retinopathy of prematurity was significant for strabismus at both 3 and 12 months (P<.001). The presence of strabismus at 3 months was found to be a highly significant predictor of strabismus at 12 months. Anisometropia, abnormal fixation, and unfavorable retinal structure also were significant predictors of strabismus at 1 year. The total prevalence of strabismus in the first year of life was 14.7%. CONCLUSION: The presence of acute-phase retinopathy of prematurity places the premature infant at increased risk for strabismus.

Cryotherapy↗
PubMed1996

Early retinal vessel development and iris vessel dilatation as factors in retinopathy of prematurity. Cryotherapy for Retinopathy of Prematurity (CRYO-ROP) Cooperative Group.

OBJECTIVE: To determine whether the extent of retinal vessel development present on early screening examinations for retinopathy of prematurity has prognostic value? DESIGN: The prospectively collected data from the Multicenter Trial of Cryotherapy for Retinopathy of Prematurity were used to compare the development of acute retinopathy of prematurity and long-term structural and visual outcomes for eyes with differing extents of retinal vessel development. PATIENT: Study patients had eyes with the following vessel development. In zone I eyes, vessels extended from the disc less than twice the distance from the disc to the macula. In zone II eyes, vessels extended beyond zone I but not to the nasal ora serrata. Transitional eyes had vessels partly in zone I and partly in zone II. RESULTS: The chance of developing threshold retinopathy of prematurity was inversely related to the early degree of vessel development: 54% for zone I eyes, 25% for transitional eyes, and 8% for zone II eyes. The presence of prominent iris vessels at 34 to 35 weeks of postmenstrual age was associated with increased risk for all three groups; zone I eyes almost always needed treatment (94%). The chance of having an unfavorable anatomic alteration of the posterior fundus, or poor vision at the ages of 1 year and 3 1/2 years, was also inversely related to the degree of early vessel development. Vessel development was an independently important factor even when birth weight, gestational age, and race were considered. CONCLUSIONS: The degree of early retinal vessel development is a significant predictor of outcome from retinopathy of prematurity. Iris vessel dilatation is an important indication for greater vigilance in following these infants.

Cryosurgery↗
PubMed1996

Partial retinal detachment at 3 months after threshold retinopathy of prematurity. Long-term structural and functional outcome. Multicenter Trial of Cryotherapy for Retinopathy of Prematurity Cooperative Group.

OBJECTIVE: To investigate the structural and functional outcome at age 4 1/2 years of eyes that had partial retinal detachment (RD) at 3 months after the occurrence of threshold retinopathy of prematurity; these eyes were involved in the Multicenter Trial of Cryotherapy for Retinopathy of Prematurity study. METHODS: Of the 531 eyes in the randomized portion of the Multicenter Trial of Cryotherapy for Retinopathy of Prematurity study, 61 had partial RD at the 3-month examination. The extent of retinal involvement was recorded, and the presence of a foveal detachment was noted. At the examination conducted at age 4 1/2 years, the fundus structure was graded into cicatricial retinopathy of prematurity outcome categories by study ophthalmologists, and the visual acuity was measured by masked examiners using the Teller Acuity Card procedure and the crowded HOTV recognition acuity test. RESULTS: Of the 61 eyes, 7 eyes continued to have partial RD at age 4 1/2 years. Of the remaining eyes, 20 eyes had structural outcomes classified as favorable in the Multicenter Trial of Cryotherapy for Retinopathy of Prematurity study, and 27 eyes had unfavorable structural outcomes. Data were unrecordable for 3 eyes and missing for 4 eyes. No difference in outcome was found for eyes with partial RD at 3 months that had undergone cryotherapy vs eyes that had served as controls. Only 6 eyes had a visual acuity better than 20/200. When partial RDs did not involve the fovea at 3 months, structural and functional outcomes at 4 1/2 years were better than when RDs involved the fovea. The best predictor of outcome was the extent of RD at 3 months. CONCLUSIONS: Partial RD present 3 months after threshold retinopathy of prematurity is unstable anatomically, and the visual outcome is generally poor. Structure and function at 4 1/2 years are related to the extent of RD and the involvement of the fovea at 3 months.

Child, Preschool↗
PubMed1996

Visual fields measured with double-arc perimetry in eyes with threshold retinopathy of prematurity from the cryotherapy for retinopathy of prematurity trial. The CRYO-Retinopathy of Prematurity Cooperative Group.

PURPOSE: To measure monocular visual field extent in very-low birth weight children in whom severe (threshold) acute-phase retinopathy of prematurity (ROP) developed in one or both eyes, and who had random assignment of eyes to cryotherapy or no cryotherapy. A control group of very-low birth weight children in whom ROP did not develop also was tested. METHODS: There were 78 children in the severe ROP group from 5 of 23 centers in the randomized trial of cryotherapy for ROP (CRYO-ROP). The comparison cohort consisted of 75 study participants in whom ROP did not develop. All subjects had birth weights of less than 1251 g. At the 5 1/2-year study examination, visual field size was measured using double-arc kinetic perimetry. Testers were masked to treatment status of each eye. Four meridia were tested: superotemporal (ST), inferotemporal (IT), inferonasal (IN), and superonasal (SN). Target size was 6 degrees. RESULTS: When blind eyes were assigned a score of 0 degree, the no-ROP, treated, and control eyes had an average visual field extent of 62 degrees, 35 degrees, 27 degrees at ST; 73 degrees, 42 degrees, 35 degrees at IT; 51 degrees, 30 degrees, 21 degrees IN; and 50 degrees, 26 degrees, 22 degrees at SN, respectively. Among 25 children who had bilateral threshold ROP and measurable fields in each eye, values for treated and control eyes were 59 versus 62 at ST, 69 versus 80 at IT, 44 versus 49 at IN, and 41 versus 48 at SN, respectively. CONCLUSIONS: Overall, visual fields in eyes that reached threshold ROP were smaller than those of eyes that did not develop ROP. When only pairs of sighted eyes were considered, visual fields in the treated eyes were 6.4 degrees smaller than those of control eyes. Therefore, it appears that a small loss of peripheral field occurs when cryotherapy prevents the development of retinal detachment.

Child, Preschool↗
PubMed1996

Visual acuity of eyes after vitrectomy for retinopathy of prematurity: follow-up at 5 1/2 years. The Cryotherapy for Retinopathy of Prematurity Cooperative Group.

PURPOSE: To provide long-term follow-up on the structural status and visual function at 5 1/2 years of age for 128 eyes of 98 infants who participated in the multicenter randomized clinical trial of cryotherapy for retinopathy of prematurity in whom total retinal detachment developed from retinopathy of prematurity (ROP) by the 3-month study examination. Fifty-four patients had lensectomy-vitrectomy procedures in one or both eyes before 1 year of age (n=72 eyes), and 44 patients did not (n=56 eyes). METHODS: When the children were 5 1/2 years of age, an eye examination was performed and residua of ROP was assessed. Recognition acuity (Early Treatment of Diabetic Retinopathy Study chart) and grating visual acuity (Teller acuity card procedure) assessments were undertaken by testers who were masked to the status of each of the child's eyes. RESULTS: At least partial retinal attachment was present at 5 1/2 years in 21% compared with 28% at 1 year of age (not significant). All except one of the eyes tested at 5 1/2 years had vision limited to light perception or no light perception, regardless of whether a vitrectomy had been performed. One eye that underwent vitrectomy had minimal pattern vision. The two eyes that were reported previously to have minimal pattern vision at 1 year of age were blind at the longer-term follow-up. CONCLUSIONS: The poor visual outcome after a lensectomy-vitrectomy procedure for retinal detachment due to ROP demands that emphasis be placed on prevention of retinal detachment in premature infants.

Child, Preschool↗
PubMed1995

Grating visual acuity in eyes with retinal residua of retinopathy of prematurity. The Cryotherapy for Retinopathy of Prematurity Cooperative Group.

OBJECTIVES: To compare grating visual acuity of eyes with varying severity of retinal residua of retinopathy of prematurity to grating visual acuity of eyes that did not have acute-phase retinopathy of prematurity, showed no ocular abnormalities on follow-up, and were from patients who passed neurodevelopmental screening questions. DESIGN: Monocular grating visual acuity was measured by means of the Teller acuity card procedure when children reached 1, 2, 3 1/2, and 4 1/2 years of age. PATIENTS: A total of 1398 children with birth weights less than 1251 g whose acute-phase retinopathy of prematurity was documented as part of the Multicenter Cryotherapy for Retinopathy of Prematurity Study and who participated in follow-up visual acuity testing. RESULTS: Eyes with no or mild residua of retinopathy of prematurity showed a mean visual acuity similar to that of the comparison group. Eyes in a subgroup with abnormally straightened temporal retinal vessels showed a mean visual acuity approximately 1 octave below that of the comparison group. Mean visual acuity scores from eyes with macular heterotopia ranged from 1 octave (at 1 year) to more than 2 octaves (at 4 1/2 years) below the mean visual acuity of the comparison group. Mean visual acuity scores for the few eyes in the retinal fold or partial detachment group that had quantifiable visual acuity were well below the means for the comparison group. CONCLUSIONS: Acute-phase retinopathy of prematurity that regresses without retinal residua produces no deficit in grating visual acuity between 1 and 4 1/2 years of age. In contrast, eyes with macular heterotopia show a visual acuity deficit, and the deficit is greater at older than at younger ages. Eyes with retinal fold or partial detachment that have measurable visual acuity show large visual acuity deficits at all ages.

Acute Disease↗
PubMed1995

Comparison of recognition and grating acuities in very-low-birth-weight children with and without retinal residua of retinopathy of prematurity. Cryotherapy for Retinopathy of Prematurity Cooperative Group.

PURPOSE: To compare recognition (letter) and resolution (grating) acuity in eyes with and without retinopathy of prematurity (ROP) residua. METHOD: Letter acuity measured with the crowded HOTV chart or pocket cards (Good-Lite), and grating acuity measured with the Teller Acuity Card (TAC) procedure, were compared at the 3 1/2- and 4 1/2-year follow-up exams in the CRYO-ROP study. Testers were unaware of the retinal status of individual eyes. RESULTS: Measurable scores for both letter and grating acuity were obtained from 1694 eyes at 3 1/2 years and 2101 eyes at 4 1/2 years. Correlation analysis showed that the relation between crowded HOTV and grating acuity scores was best described by a quadratic function, with r2 values of 0.57 at 3 1/2 years and 0.68 at 4 1/2 years. Difference scores were calculated for each eye by subtracting the log of the HOTV score (converted to cyc/deg based on the convention that 20/20 = 30 cyc/deg) from the log TAC score. Normal eyes showed HOTV acuity that was higher than TAC acuity by an average of 0.37 octave (SD = 0.46, n = 1150) at 3 1/2 years and 0.27 octave (SD = 0.43, n = 1337) at 4 1/2 years. HOTV and grating acuity scores were similar to each other in eyes with retinal residua of ROP. Overall, eyes with acuity better than 20/150 to 20/300 tended to show better HOTV than grating acuity, whereas those with acuity below 20/150 to 20/300 generally showed better grating than HOTV acuity. CONCLUSIONS: There is a significant correlation between crowded HOTV letter acuity and TAC grating acuity in young children for normal eyes and eyes with ROP residua. In both groups of eyes, eyes with lower acuity show better grating than letter acuity, whereas eyes with better acuity show slightly higher letter than grating acuity.

Child, Preschool↗
PubMed1994

Effect of acute-phase retinopathy of prematurity on grating acuity development in the very low birth weight infant. The Cryotherapy for Retinopathy of Prematurity Cooperative Group.

PURPOSE: To examine the development of grating acuity in four groups of eyes in the Multicenter Study of Cryotherapy for Retinopathy of Prematurity (CRYO-ROP): eyes with no ROP; eyes with less-than-prethreshold ROP; eyes with prethreshold ROP; and eyes with threshold ROP that were randomized to serve as controls (not treated with cryotherapy). METHODS: Subjects were 1398 children with birth weights < 1251 g whose acute-phase ROP was documented as part of the CRYO-ROP study. Monocular grating acuity was measured using the Teller acuity card procedure when children reached 1, 2, 3 1/2, and 4 1/2 years of age. RESULTS: Eyes in the no-ROP and less-than-prethreshold groups showed nearly identical acuity development. Eyes with prethreshold ROP showed mean acuity similar to the no-ROP group at 1 and 2 years, but slightly below the no-ROP group at 3 1/2 and 4 1/2 years. Only 50% of eyes in the threshold untreated ROP group had measurable acuity. These eyes showed mean acuity scores that were approximately 1 octave below those of the no-ROP group at all four test ages. When data from eyes with ROP residua or other ocular abnormalities, and data from eyes of children who were unable to pass the study developmental screening items, were excluded, acuity development was similar among groups. CONCLUSIONS: Mild (less-than-prethreshold) ROP has no effect on the development of grating acuity in children between 1 and 4 1/2 years of age. Moderate (prethreshold) ROP is associated with reduced acuity at 3 1/2 and 4 1/2 years. In general, severe (threshold untreated) ROP results in moderate to severe reductions in acuity at all ages between 1 and 4 1/2 years. However, a small number of children with severe ROP show normal acuity development.

Acute Disease↗
PubMed1993

Prognostic factors in the natural course of retinopathy of prematurity. The Cryotherapy for Retinopathy of Prematurity Cooperative Group.

BACKGROUND: There exists no reliable information that allows the ophthalmologist to predict with any degree of certainty a particular infant's chances of requiring surgical treatment for retinopathy of prematurity (ROP) or of reaching an unfavorable outcome on the basis of the retinal findings at the time of the nursery examination. METHODS: In the Multicenter Trial of Cryotherapy for Retinopathy of Prematurity (CRYO-ROP), 4099 infants weighing less than 1251 g at birth underwent eye examinations that began at 4 to 6 weeks after birth and subsequently continued at 2-week intervals. Independent variables in the population were studied using multiple logistic regressions. RESULTS: An increased risk of reaching threshold ROP was found associated with lower birth weights, younger gestational age, white race, multiple birth, and being born outside a study center nursery. For infants who developed ROP (66%), corresponding probabilities are presented for developing severe ("threshold") ROP or of having an unfavorable macular outcome. The risk of an unfavorable macular outcome was increased with zone 1 ROP, "plus" disease, the severity of the stage, and the amount of circumferential involvement. A higher risk also was associated with a rapid rate of progression of ROP to prethreshold disease but not with the postconceptional age at which ROP was first noted. CONCLUSION: The findings indicate that the ocular characteristics of ROP, along with some easily identifiable and available basic systemic and demographic information about an infant, can assist the ophthalmologist in understanding variations in an individual baby's chance for a good or poor macular outcome.

Child, Preschool↗
PubMed1992

Ocular cosmesis in retinopathy of prematurity. The Cryotherapy for Retinopathy of Prematurity Cooperative Group.

We report the externally apparent outcome in the natural history cohort (n = 4099) that was followed up prospectively in the Multicenter Trial of Cryotherapy for Retinopathy of Prematurity. The overall incidence of an adverse cosmetic outcome in the survivors who were examined 12 months post term (n = 2759) was 15.1%. Adverse cosmetic outcomes included strabismus (12.8%), nystagmus (3.3%), total retrolental membrane (1%), epiphora (0.6%), corneal opacity (0.6%), cataract (0.3%), and episcleral hyperemia (0.3%). A comparable subgroup examined 24 months post term showed strabismus (14.4%), nystagmus (2.2%), epiphora (0.5%), corneal opacity (0.7%), cataract (0.5%), episcleral hyperemia (0.5%), lid fissure asymmetry (2.4%), and corneal diameter asymmetry (2.0%). The rate of adverse aesthetic outcome was greatest in eyes that had developed more severe acute retinopathy of prematurity and an unfavorable structural outcome. In patients with bilateral threshold retinopathy of prematurity who underwent no therapeutic ocular procedures, other than randomized assignment to undergo cryotherapy in one eye, more frequent adverse cosmetic outcomes were found in the untreated eyes.

Acute Disease↗
PubMed1992

Development of myopia in infants with birth weights less than 1251 grams. The Cryotherapy for Retinopathy of Prematurity Cooperative Group.

The authors report on the incidence of myopia in a large group of premature infants with birth weights of less than 1251 g followed as part of the multicenter study of Cryotherapy for Retinopathy of Prematurity. None of the eyes reported here underwent cryotherapy. Eyes were refracted using cycloplegic retinoscopy at 3 months (n = 2916), 12 months (n = 2626), and 24 months (n = 961 at 5 of the 23 centers) after term. Myopia was observed in approximately 20% of the children at each test age. The percentage of high myopia (greater than or equal to 5 diopters) doubled from 2% to 4.6% between 3 and 12 months and remained stable thereafter. Lower birth weight and increasing severity of retinopathy of prematurity (ROP) were strong predictors of myopia and high myopia. In addition, anisometropia, astigmatism, and the presence of posterior pole residua from ROP also were associated with a higher incidence of myopia and high myopia.

Anisometropia↗
PubMed1991

Operational aspects of terminating randomization in the Multicenter Trial of Cryotherapy for Retinopathy of Prematurity. Cryotherapy for Retinopathy of Prematurity Cooperative Group.

The Multicenter Trial of Cryotherapy for Retinopathy of Prematurity (CRYO-ROP) is a randomized clinical trial sponsored by the National Eye Institute (NEI) designed to test whether cryotherapy applied to eyes of premature infants with a specified extent of stage 3+ ROP significantly decreases the incidence of an unfavorable outcome. An unfavorable outcome is defined as either retinal detachment or a retinal fold and was determined at 3 months posttreatment by the use of a masked photographic system. Enrollment into the trial was terminated on recommendation of the Data and Safety Monitoring Committee 9 months before the scheduled closing date for enrollment because of demonstrated treatment benefit. The purpose of this article is to discuss the operations involved in the orderly termination of enrollment and dissemination of results from this trial. These activities included preparation of trial participants and staff, release of trial information, continuing patient care, data collection and coding, and publication of trial results.

Blindness↗
PubMed1991

Statistical considerations in terminating randomization in the Multicenter Trial of Cryotherapy for Retinopathy of Prematurity. Cryotherapy for Retinopathy of Prematurity Cooperative Group.

The Multicenter Trial of Cryotherapy for Retinopathy of Prematurity (CRYO-ROP) was a randomized trial designed to test whether cryotherapy applied to the retina significantly decreased the incidence of retinal detachment, retinal fold, or retrolental "mass." Randomization into the trial was terminated on recommendation of the Data and Safety Monitoring Committee 9 months before the scheduled end of the intake period. At the time of the decision, a favorable outcome at 3 months posttreatment occurred more frequently in eyes treated with cryotherapy (78%) as compared to untreated eyes (57%) (chi 2 = 20.5). The basic statistical method used in monitoring the results was conditional power (or stochastic curtailment). Several other issues were considered in deciding to terminate the trial, including the examination of results across subgroups and clinical centers, the completeness of follow-up, clinical assessment of outcome, and long-term consequences of the treatment.

Bias↗
PubMed1991

Incidence and early course of retinopathy of prematurity. The Cryotherapy for Retinopathy of Prematurity Cooperative Group.

In the Multicenter Trial of Cryotherapy for Retinopathy of Prematurity (ROP), 4099 infants weighing less than 1251 g at birth underwent sequential ophthalmic examinations, beginning at age 4 to 6 weeks, to monitor the incidence and course of ROP. Overall, 65.8% of the infants developed ROP to some degree; 81.6% for infants of less than 1000 g birth weight. As expected, ROP incidence and severity were higher in lower birth weight and gestational age categories. Black infants appeared less susceptible to ROP, of all severity categories, than nonblack infants. The timing of retinal vascular events correlated more closely with postconceptional age than with postnatal age, implicating the level of maturity more than postnatal environmental influences in governing the timing of these vascular events. These results include the current incidence of various severity stages of ROP found in the United States and provide new insight into the development of ROP.

Cryosurgery↗
PubMed1991

Visual acuity in infants after vitrectomy for severe retinopathy of prematurity.

During the course of the Multicenter Trial of Cryotherapy for Retinopathy of Prematurity (CRYO-ROP), 98 infants (129 eyes) from the randomized segment of the trial developed total retinal detachment from retinopathy of prematurity (ROP) before the 1-year examination. The authors report as a case series the results of acuity card assessment of monocular grating acuity at 1 year in 53 infants (71 eyes) postvitrectomy and in 45 infants (58 eyes) who had retinal detachments but who did not undergo retinal reattachment surgery. The decision to undertake and the surgical technique used for a retinal reattachment procedure was not part of the randomized CRYO-ROP trial. Two eyes of one infant had pattern vision at the lowest measurable threshold after vitrectomy. None of the remaining eyes that had undergone vitrectomy and none of the eyes that did not undergo vitrectomy showed evidence of pattern vision. The relatively poor visual outcomes in this case series suggest that efforts are well-spent in attempting to prevent retinal detachment in ROP.

Cryosurgery↗
PubMed1991

28-day survival rates of 6676 neonates with birth weights of 1250 grams or less.

Survival rates specific for birth weight, gestational age, sex, and race are described for 6676 inborn neonates who weighed less than 1251 g at birth and were born during 1986 through 1987. Overall 28-day survival increased with gestational age and birth weight, from 36.5% at 24 weeks' gestation to 89.9% at 29 weeks' gestation, or from 30.0% for neonates of 500 through 599 g birth weight to 91.3% for neonates of 1200 through 1250 g. The expected birth weight-specific survival advantage for female neonates and black neonates diminished when the data were controlled for gestational age, showing that certain previously reported survival advantages are based on lower birth weight for a given gestational age. Multivariate analysis showed that all tested variables were significant predictors for survival, in order of descending significance: gestational age and birth weight, sex, race, single birth, and small-for-gestational-age status. The powerful effect of gestational age on survival highlights the need for an accurate neonatal tool to assess the gestational age of very low birth weight neonates after birth.

Black or African American↗