An international comparison of retinopathy of prematurity grading performance within the Benefits of Oxygen Saturation Targeting II trials.

PurposeTo investigate whether the observed international differences in retinopathy of prematurity (ROP) treatment rates within the Benefits of Oxygen Saturation Targeting (BOOST) II trials might have been caused by international variation in ROP disease grading.MethodsGroups of BOOST II trial ophthalmologists in UK, Australia, and New Zealand (ANZ), and an international reference group (INT) used a web based system to grade a selection of RetCam images of ROP acquired during the BOOST II UK trial. Rates of decisions to treat, plus disease grading, ROP stage grading, ROP zone grading, inter-observer variation within groups and intra-observer variation within groups were measured.ResultsForty-two eye examinations were graded. UK ophthalmologists diagnosed treat-requiring ROP more frequently than ANZ ophthalmologists, 13.9 (3.49) compared to 9.4 (4.46) eye examinations, P=0.038. UK ophthalmologists diagnosed plus disease more frequently than ANZ ophthalmologists, 14.1 (6.23) compared to 8.5 (3.24) eye examinations, P=0.021. ANZ ophthalmologists diagnosed stage 2 ROP more frequently than UK ophthalmologists, 20.2 (5.8) compared to 12.7 (7.1) eye examinations, P=0.026. There were no other significant differences in the grading of ROP stage or zone. Inter-observer variation was higher within the UK group than within the ANZ group. Intra-observer variation was low in both groups.ConclusionsWe have found evidence of international variation in the diagnosis of treatment-requiring ROP. Improved standardisation of the diagnosis of treatment-requiring ROP is required. Measures might include improved training in the grading of ROP, using an international approach, and further development of ROP image analysis software.

Development of electroretinogram and rod phototransduction response in human infants.

PURPOSE: To describe and analyze developmental change from birth through maturity of human electroretinogram (ERG) response, especially in terms of rod phototransduction as represented in the ERG a-wave. METHODS: Electroretinograms were recorded from 16 human infants from 5 to 270 days of age, two children 1.9 and 3.4 years of age, and 13 older subjects between 10 and 43 years of age. A range of full-field, white-light flashes up to intensities sufficient to saturate a-wave and b-wave amplitudes and a-wave rate-of-rise was used. The a-wave leading edge, the a-wave and b-wave amplitudes, and the b/a-wave ratio at maximum intensity were analyzed using a model of the activation steps of the G-protein phototransduction cascade. This model, applied to a-waves, provides three parameters interpretable in terms of rod phototransduction: amax (a-wave maximum amplitude, proportional to circulating dark current), A' (estimated constant of transduction amplification), and t'eff (sum of brief delays associated with the cascade steps). RESULTS: Both amax and bmax (maximum b-wave amplitude) increased rapidly from birth. bmax reached apparently mature values by approximately 6 months, but amax, and thus (b/a)max (b/a ratio at maximum intensity), did not reach mature values until sometime after the third or fourth year. Similarly, A' was immature at birth at approximately 25% to 50% of adult levels at intensities below rate-of-rise saturation. For the youngest infants, rate-of-rise saturation appeared to occur at lower effective isomerizations per rod compared to that of the adult. Following a time course similar to that of amax, full maturity for A' probably was not reached before 5 years of age. CONCLUSIONS: Results from the a-wave analysis are consistent with immaturities in the rod photoreceptors early in life. The difference from those of the adult may be explained by lower neonatal concentrations in one or more of the transduction substrates, decreased outer segment length, and, possibly, decreased density of some membrane proteins mediating the cationic dark current. Early adultlike b-wave amplitudes suggest early maturity for the inner retinal elements (rod bipolar and Müller cells) underlying b-wave response, compared to the photoreceptors.

Acuity card assessment of visual function in the cryotherapy for retinopathy of prematurity trial.

The primary outcome measure of the effectiveness of cryotherapy in the original design of the Multicenter Trial of Cryotherapy for Retinopathy of Prematurity (CRYO-ROP) was the anatomic status of the retina, as documented by fundus photography 3 months and 12 months after infants had received treatment. The authors describe the addition of a measurement of visual function, the Acuity Card procedure, to the CRYO-ROP study. After training, four visual-acuity testers attempted to measure monocular grating acuity in all randomized infants and approximately one fourth of the natural-history infants in the study, tested at 1 year postcryotherapy or 1 year postterm. In 95% of infants on whom testing was attempted, monocular acuity values from each eye were obtained. Interobserver test-retest results on 25 eyes of 13 randomized infants agreed to within one octave or better in all but one of the eyes. The high testability rate and good interobserver agreement suggest that the Acuity Card procedure has been a successful method of assessing visual function in the CRYO-ROP study.

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.

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.

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.

Color vision measured with pseudoisochromatic plates at five-and-a-half years in eyes of children from the CRYO-ROP study.

PURPOSE: To investigate the prevalence of color deficits at age 5 1/2 years in preterm children with birth weights of less than 1251 g who participated in the multicenter Cryotherapy for Retinopathy of Prematurity (CRYO-ROP) study. METHODS: Two cohorts of CRYO-ROP participants served as subjects: 1055 children who participated in a long-term study of the natural history of ROP at 5 of the 23 CRYO-ROP centers, and 187 children (from all 23 study centers) who had threshold ROP in both eyes and who were randomized to receive cryotherapy in 1 eye. Monocular color vision was tested at age 5 1/2 years, using the Standard Pseudoisochromatic Plates, part 2 (SPP2) for acquired color vision defects. RESULTS: In the Natural History cohort, prevalence of red-green (R-G) color deficits was 6.6% for males and 1.0% for females, similar to that of the general adult population. Prevalence of blue-yellow (B-Y) color deficits was 2.8% for males and 2.2% for females, more than 200 times that in the general adult population. Prevalence of B-Y deficits was not related to birth weight, gestational age, acute-phase ROP, optic atrophy, or retinal residua of ROP, but was related to visual acuity. In the Threshold ROP cohort, color vision deficits were no more likely in eyes that had received cryotherapy than in control eyes. CONCLUSIONS: The results confirm an increased prevalence of B-Y deficits in children born before term, and provide evidence that the increased prevalence is not related to birth weight, gestational age, or severity of ROP within this group of preterm children. No evidence was found to indicate that cryotherapy increased the rate of color vision deficits in eyes with threshold ROP.

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.

Sequelae of arrested mild retinopathy of prematurity.

Twenty-six infants with totally resolved low-grade retinopathy of prematurity (ROP) were compared with a similar group of 38 premature infants in whom no retinopathy had ever developed in the nursery. At the examination performed at a physiologic age of 1 year, the two groups were almost indistinguishable with respect to their refractive errors, strabismus, and amblyopia. The incidence and severity of mild to moderate anisometropia was increased in the resolved ROP group. It appears that there is a group of infants in whom absolute resolution occurs, with few residua of active ROP. This is especially true when there are no anatomical retinal findings consistent with low-grade cicatricial retrolental fibroplasia at 1 year of age.

The correlation of visual function with posterior retinal structure in severe retinopathy of prematurity. Cryotherapy for Retinopathy of Prematurity Cooperative Group.

The Multicenter Trial of Cryotherapy for Retinopathy of Prematurity previously reported reduced incidence of both poor structural and functional outcomes after cryotherapy. We compared the results in 304 eyes of patients in the randomized portion of the trial in whom both structural and functional assessments were performed 12 months after randomization. Two hundred fifty-five eyes (83.9%) had concordant outcomes: 153 eyes had favorable structural and functional outcomes and 102 eyes had unfavorable structural and functional outcomes. Twenty-nine eyes (9.5%) had discordant outcomes: 20 eyes had favorable structural and unfavorable functional outcomes and nine eyes had unfavorable structural and favorable functional outcomes. The small number of discordant outcomes could generally be accounted for by three factors: (1) retinal abnormalities beyond those considered in the photographic grading system (12 eyes), (2) nonretinal visual pathway disease (five eyes), or (3) false-positive and false-negative results in the measurement systems used to evaluate structure and function (five eyes). In 20 eyes (6.6%), photographs could not be graded or the visual acuity was untestable. We conclude that the appearance of the posterior pole of the eye correlates well with grating acuity in the 12-month-old infant with a history of severe retinopathy of prematurity.

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.

Correlation of retinopathy of prematurity in fellow eyes in the cryotherapy for retinopathy of prematurity study. The Cryotherapy for Retinopathy of Prematurity Cooperative Group.

OBJECTIVE: To examine the similarity of extent (sectors) and severity (stage) of acute-phase retinopathy of prematurity (ROP) between fellow eyes and the concordance of cicatricial outcomes at age 1 year of eyes that did not develop threshold disease. METHODS: Four thousand ninety-nine infants with birth weights of less than 1251 g who participated in a natural history segment of the Cryotherapy for Retinopathy study underwent biweekly eye examinations from 4 to 6 weeks after birth until retinal vasculature was complete or until ROP regressed or reached threshold severity. Eyes were categorized as follows: (1) no ROP, (2) less than prethreshold ROP, (3) prethreshold ROP, (4) threshold ROP, and (5) unable to determine. The presence and stage of ROP residua in fellow eyes were evaluated at 12 months. RESULTS: Acute-phase ROP status between 32 and 42 weeks postconceptional age showed a high degree of correspondence between fellow eyes in severity (stage) and location (zone) of ROP, presence of plus disease, and sectors of stage 3 retinopathy. More variability between eyes was seen when cicatricial status at age 1 year was examined. This higher variability was evident even though results from patients with threshold ROP (many of whom underwent cryotherapy) were excluded. CONCLUSION: The usual course of ROP during its acute phase is for fellow eyes to be very similar in ROP status. However, asymmetry between eyes is not unusual in eyes with posterior pole residua of ROP.

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.

Prediction of visual function in eyes with mild to moderate posterior pole residua of retinopathy of prematurity. Cryotherapy for Retinopathy of Prematurity Cooperative Group.

OBJECTIVE: The Multicenter Trial of Cryotherapy for Retinopathy of Prematurity (CRYO-ROP) assigned eyes with macular heterotopia to the "favorable" outcome category and eyes with retinal fold involving the macula to the "unfavorable" outcome category. This binary assignment did not agree well with measured visual acuity outcome. We tested the hypothesis that rating structural outcome on a continuum from less to more severe would improve prediction of visual acuity in eyes with macular heterotopia or retinal fold. DESIGN: Fundus photographs of the 69 eyes in the CRYO-ROP trial that had macular heterotopia (n = 55) or retinal fold (n = 14) at the 1-year follow-up were analyzed for severity of macular heterotopia, macular elevation, and pigmentary disturbances. Each physician author estimated each eye's predicted Snellen acuity, based on the photographic findings and clinical expertise. These results were compared with the grating acuity obtained at ages 1 and 3 1/2 years with the Teller Acuity Card procedure and with letter acuity obtained at age 3 1/2 years with the crowded HOTV test. PATIENTS: The 69 eyes were from 59 patients in the randomized portion of the CRYO-ROP trial. RESULTS: Although eyes with retinal fold tended to have greater visual impairment than eyes with macular heterotopia, there was a wide variation in acuity in both groups, and physicians were unable to predict visual acuity from retinal appearance. CONCLUSION: The physician cannot reliably predict either grating acuity or letter acuity in eyes with macular heterotopia or macular fold due to retinopathy of prematurity. There is no substitute for periodic visual acuity testing in these eyes.

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.

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.

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.

A revised classification of retinopathy of prematurity.

We have developed a classification system for the acute phases of retinopathy of prematurity based on more than 13,000 ophthalmoscopic examinations of more than 3,400 premature infants between 1968 and 1982. Two forms of the active disease exist. Retinopathy of prematurity is a relatively common mild disease and retinopathy of prematurity plus is characterized by rapid progression and posterior pole vascular tortuosity and dilation. The five grades progress from peripheral vascular abnormalities (Grade 1) through a demarcation line (Grade 2) and extraretinal neovascularization (Grade 3) to partial (Grade 4) or total (Grade 5) retinal detachment. The persistence of abnormal retinal vessels during the first year of life is considered "transitional" retinopathy of prematurity unless unequivocal cicatricial changes with macular distortion develop.

Ocular alignment after craniofacial reconstruction.

We undertook a retrospective study of 160 patients to ascertain if craniofacial reconstruction affected ocular alignment. In most patientspre-existing alignment and binocularity were unaffected by craniofacial surgery; thus, correction of any strabismus can be performed on a child without concern for disruption of muscle tissue by later craniofacial surgery.

The visual-evoked response in infants with central visual impairment.

We studied ten children with central visual impairment with a known neurologic defect and an abnormal visual-evoked response who had results of repeat electrophysiologic testing evaluated at the Children's Hospital of Philadelphia from December 1989 through July 1991. Central visual impairment is defined as poor visual function with a normal anterior visual pathway. Age at first examination ranged from 5 to 48 months with a followup of two to 31 months. Repeat visual-evoked response testing showed improvement in seven patients and no change in three. Grating acuity as measured by the Teller acuity card procedure, performed in nine of ten patients, improved in seven, showed no change in one, and declined in one. We found a potentially favorable prognosis for those infants with central visual impairment, despite an initially abnormal visual-evoked response. We used a clinical approach to this disorder to improve diagnostic categorization and prognostic capabilities in central visual impairment.