Acuity Card Procedure Research Articles

Assessment of Visual Function in Autistic Children

Children with autism demonstrate "atypical" gaze or social "looking" and frequently manifest such sterotypies as eye pressing, hand flicking, and light gazing. This study's purpose was to evaluate autistic children for visual dysfunction that may be related to the manifested visual signs and symptoms. Thirty-four autistic children, ages 2 to 11 years (median age = 7 years, 6 months) were evaluated for ocular alignment, refractive error, visual acuity, oculomotility skills, and stereopsis. None of the children manifested ocular disease, known seizure disorders, or dysmorphic features. Their developmental levels ranged from average intelligence to severely retarded. Binocular visual acuity was measured with the acuity card procedure. Monocular visual acuity was not obtained. Refractive errors ranged from -4.25 to +3.25 D; the median was plano with the near retinoscopy technique. Of the 34 children, 21% were strabismic at far and 18% were strabismic at near. Lang stereo testing was attempted on all children and completed on 17. Of the 17, all but 3 exhibited 550 sec arc. Only 14.7% of the children exhibited voluntary pursuit movements, and all the children demonstrated saccadic fixations. Thirty-one children had atypical optokinetic nystagmus (OKN) responses such as delayed onset, short duration, gaze avoidance, or stereotypic behavior. Repeated testing revealed consistent visual responses on OKN and visual acuity. Given these findings, research with this population should be pursued further.

Visual acuity in low birth weight (1500–2500 g) neonates

Binocular grating acuity was tested in 138 low birth weight (LBW) neonates (birth weights ranging from 1500 to 2500 g) by means of the prototype version of the Acuity Card Procedure. No surrounding screen was used. Mean visual acuity of 107 neonates successfully assessed at mean corrected ages of −1.9 weeks (± 1.9 weeks) amounted to 0.58 cycles/degree (S.D. 0.71 octaves). Success rate was 77.5%. Mean postnatal age was 2.3 weeks (± 1.6 weeks). Acuity values of various subgroups ranged between 0.68 cycles/degree (S.D. 1.3 octaves) in low-risk, small for gestational age (SGA) preterms ( n = 7), to 0.56 cycles/degree (S.D. 0.7 octaves) in SGA fullterms ( n = 34), independent whether at low-or at high-risk. These differences were not significant, although with multiple regression analysis with adjustment for corrected age of testing, mean acuity of low-risk preterms was slightly better than of low-risk fullterms ( P = 0.055). No significant change of acuity over corrected age could be demonstrated, except for a slight progress ( r = 0.57; P < 0.05) in the subgroup of 13 low-risk fullterms. The high variability of acuity values in neonates and the slow acuity development at term age hamper assessment of differences between various subgroups of neonates.

Grating-acuity in children. Normal values of visual acuity in children up to 13 years as assessed by the acuity card procedure.

The acuity card procedure proved to be a useful method for assessing visual acuity in children. Normal values of visual acuity measured by this method had already been assessed in children up to four years. To enable application of the test in older children this study obtained values in a group of 396 normal children, aged three months to 13 years. The mean curve as well as the 10th centile was calculated in different age groups. A considerable variation of acuity values causing a 'dip' in the 10th centile was found in the ages 18 to 24 months. A smaller 'dip' was found in the ages 48 to 52 months. This has to be attributed to behavioural properties connected with age. The results obtained in the group of children under four years of age corresponded fairly well with other studies. In schoolchildren a fair agreement could also be found between the data obtained using the acuity card procedure and the data obtained with the Landolt-C rings. Obtaining normal values for the acuity card procedure in children covering a wide age range facilitates recognition of visual handicap in children who are difficult to assess.

Using the Acuity Card Procedure to Assess Visual Acuity in Children with Severe and Multiple Impairments

This study evaluated the Acuity Card Procedure, an acuity test originally developed for assessing the visual acuity of infants. The study found that, of the 36 children assessed, 42 percent responded; however, after a simple intervention, the response rate increased to 85 percent. These results suggest that the Acuity Card Procedure can be useful in assessing the visual acuity of children with severe visual and multiple impairments.

Assessing Visual Acuity of Visually Impaired Children Using the Teller Acuity Card Procedure

Assessing Visual Acuity of Visually Impaired Children Using the Teller Acuity Card Procedure

Untersuchungen zur normalen und gestörten visuellen Entwicklung mit Preferential Looking (PL)

Normal and disturbed development of grating acuity in preverbal infants has been studied using the Teller acuity card procedure. The results of 195 normal and 34 premature children are in good accordance with those reported in the literature. In more than 86% no interocular differences of grating acuity could be detected in these groups. On the other hand the incidence of interocular acuity differences reached 30% in 37 cases showing monolateral convergent squint. This is much higher than has been reported in current literature and may indicate that grating and Snellen acuity correlate better than expected in infants' squint amblyopia. As to the problem of monitoring early amblyopia therapy by PL, four longitudinal cases are presented.

DELAYED VISUAL MATURATION: OPHTHALMIC AND NEURO‐DEVELOPMENTAL ASPECTS

Delayed visual maturation (DVM) can present as an isolated anomaly (type 1A), but can be compounded by perinatal problems (type 1B), severe neurodevelopmental delay (type 2), or ocular anomalies/nystagmus (type 3), in which group the common feature appears to be nystagmus. The neurodevelopmental and ophthalmic aspects of 26 infants with DVM were studied. Onset of visual improvement, rate of acquisition of normal vision and eventual outcome were studied quantitatively, using an adaptation of the acuity card procedure. Neurodevelopmental assessment was performed after visual improvement. The results support the long-held clinical impression that if blindness is the presenting feature, neurodevelopmental outlook is excellent. DVM could represent a defect in the extrageniculostriate visual system, and the onset of vision in all types--and the development of nystagmus in type 3--could herald the emergence of geniculostriate function.

Visual Acuity Assessment from Birth to Three Years Using the Acuity Card Procedure: Cross-Sectional and Longitudinal Samples

We used the Teller Acuity Cards (TAC) to test 7 groups of 20 healthy infants and children ranging in age from 1 week to 36 months. We also tested 27 of these children at least twice within their first year. We had two primary goals: (1) to provide normative data on the development of visual acuity as assessed with the new version of the TAC (Vistech, Inc.) and (2) to investigate the predictive value of the TAC. The results from the cross-sectional samples show that our estimates of visual acuity are consistent with those reported by other researchers who used earlier versions of the TAC. The longitudinal data indicate that, on the average, an early estimate of visual acuity was not predictive of a later estimate, at least within the first year. The results are discussed in terms of the usefulness of the TAC for testing normal and clinical populations.

The Acuity Card Procedure: Longitudinal Assessments

Traditional methods of visual assessment in preverbal pediatric patients rely on refined but subjective measurement techniques. A standard ophthalmologic examination includes evaluation of a child's fixation patterns, with performance ranked on the basis of ability to fix and follow an object (F & F) or maintain central, steady fixation (CSM). In the hands of a skilled clinician, these evaluations are important for diagnosis and treatment. Documentation of quantitative changes in visual abilities of preverbal patients, however, has only recently become feasible. We began using the acuity card procedure in our pediatric clinical practice more than 3 years ago. This assessment, a modified version of the standard Forced-Choice Preferential Looking paradigm (FPL), provides quantitative evaluation of visual functioning in preverbal patients. The total number of patients assessed on one or more occasions exceeds 900. Of this group, we followed 83 patients with at least four acuity card evaluations on separate visits. Thirty of these patients, all with different diseases, have been evaluated with acuity cards on six or more visits. We found the information provided by the acuity card assessments extremely helpful in quantifying the developmental and therapeutic changes in vision, previously monitored only qualitatively.

The acuity card procedure: theory and practice

The acuity card procedure: theory and practice

Do we need to measure the vision of children?

With the advent of the acuity card procedure, it is now possible to measure quantitatively the vision of infants and young children in a routine clinical setting. Over a 19 month period 1177 tests were performed on 586 patients; ages ranged from 0.5 weeks to 23 years. Overall 1102 (93%) were successful, as were 588 of the 627 (94%) tests performed on children under the age of two years when no conventional acuity test is possible. The results serve as a background on which the argument for and against the need to measure the vision of children is considered.

Acuity assessment of non-verbal infants and children: clinical experience with the acuity card procedure.

The acuity card procedure was used to assess the visual acuity of 510 neurologically normal and abnormal infants and children. Acuity estimates were obtained for 93 per cent of 842 binocular and 279 monocular tests. The observed development of binocular acuity of normal fullterm and preterm infants agreed well with previous reports using the traditional forced-choice preferential looking technique. Monocular tests seemed to support earlier suggestions that grating acuity may be relatively insensitive to strabismic amblyopia. Infants at risk of later neurological deficits but developing normally had only a slight delay in development of acuity, but there was a high incidence of acuity deficits (54 per cent) among those with severe neurological defects. The great majority of a group of multiply handicapped children had low acuity for age. Repeat tests showed a high degree of test-retest consistency. The acuity card procedure was a successful and useful method for assessing the acuity of infants and children who cannot be tested with standard ophthalmological methods.

The Teller Acuity Card Procedure: An Acuity Screening Technique for Pre-Verbal Children

The acuity card procedure has been proposed as an acuity screening technique for pre-verbal children because of its ease and speed of use and the availability of age norms. In the present study, th...

Grating and recognition acuities of young amblyopes.

The visual acuities of 36 young amblyopes were determined by (a) conventional recognition tests (near and distance) and (b) an adapted grating acuity card procedure. Considerable agreement between the estimates of acuity obtained with each method was demonstrated, which was generally less than, or equal to, the mean difference between adjacent Snellen lines (4.5 c deg-1). Estimates of grating acuity obtained with vertical gratings did not differ significantly from those obtained with horizontal gratings. There was no difference between the subjects' ability to detect the grating (acuity) and accurately to discriminate target orientation (horizontal or vertical). The results of the experiment are discussed in relation to previous findings of a discrepancy between grating and recognition acuities in amblyopia, and the clinical use of the acuity card procedure.

A clinical trial of the acuity card procedure

A clinical trial of the acuity card procedure

VISUAL ACUITY IN VERY LOW BIRTH WEIGHT INFANTS AT 6 WEEKS OF (CORRECTED) AGE

We studied the effect of early visual experience on the development of visual acuity (VA) in preterm infants. We assessed VA using the acuity card method in 63 very low birth weight (VLBW) infants, bwt 700-1495g (1150±240;X±SD), gest. age 25.8-35.0 wks (30.2±4.3). VA was assessed at 11.3-20.3 wks postnatal age (pa) (15.8±2.2), corresponding with 2.1-9.1 wks corrected age (ca) (6.0±1.3). Funduscopy was normal in all infants. The results were compared with those obtained in fullterm low risk infants at the age of 6.8 and 15.9 wks:*: min. of arc ± octaves (17.7 min. of arcx6/106 Snellen equiv.) The results show that visual acuity assessed with the acuity card procedure is significant lower (p<0.01. Student's t-test) in VLBW infants in comparison with low risk infants of the same postnatal age, but is not different when age is corrected for prematurity. The present results fail to demonstrate an acceleration of acuity development by early visual stimulation.

Validation of the Acuity Card Procedure for Assessment of Infants with Ocular Disorders

The acuity card procedure has been shown to be a rapid method for the assessment of monocular and binocular grating acuity in normal infants from birth through 36 months of age. The current study seeks to validate the procedure further by using the acuity cards to assess 20 2- to 8-month-old infant patients with ocular disorders, including aphakia, strabismus, ptosis, and orbital hemangioma. Assessments were made with the acuity cards by two different observers, both blind to the infant's diagnosis, and by a third observer using a traditional forced-choice preferential looking (FPL) procedure. One hundred percent of the infant patients completed both binocular and monocular acuity card testing in an average time of 8 minutes per test. Interobserver agreement between acuity card observers and inter-technique agreement were high, and were sustained in individual cases in which the infant's acuity was not predictable from its visible signs. These results help to establish the potential clinical utility of the acuity card procedure for the assessment of infant patients.

BINOCULAR VISUAL ACUITY OF NEONATES: THE ACUITY CARD PROCEDURE

The acuity card procedure is a variant of the forced-choice preferential looking technique. In this study, four observers each tested 10 infants (all healthy fullterm neonates) with acuity cards containing either a one-aperture or a two-aperture stimulus configuration. For both card types the mean test time was eight minutes. No effect on acuity results was found between the two different configurations. The mean acuity values were within one octave of those reported in most previous behavioral studies of the acuity of neonates. The authors consider that the acuity card procedure provides a rapid, accurate technique for assessment of healthy newborn infants in a hospital setting.

Assessment of visual acuity in infants and children: the acuity card procedure.

The 'acuity card' procedure described here is a simplified method of testing visual acuity of infants and young children, and has been developed to allow preferential looking to be assessed in a laboratory or clinic. A higher proportion of children can be tested successfully than has been reported for more traditional procedures. Initial studies indicate that the acuity card procedure is a fast, accurate method for assessing the acuity of normal infants and children, and those with visual or neurological impairments, across a wide age-range and in both clinical and laboratory settings.

Visual acuity in neonates: The acuity card procedure

The forced-choice preferential looking procedure (FPL: Teller, 1979) was modified to accommodate a yes/no signal detection task for measuring infants' detection of motion. Three experiments are reported that assessed the reliability of detectabilities derived from this new procedure, the sensitivity of the procedure to age differences in motion detectability, and the comparability of estimates of signal detectability produced by the new procedure and the standard, two-alternative, forced-choice procedure (2AFC). The stability of detectability over 1 week was moderately high (r = .77), and consistency within a session was quite high (r = .87). Six-week-olds were much less sensitive to motion than were 14-week-olds. The estimates of signal detectability produced by the yes/no procedure were comparable to those produced by the 2AFC procedure. The results demonstrate for the first time that a rigorous yes/no signal detection procedure can be used in infant visual psychophysics.