Acuity Card Procedure Research Articles

Can Slip of the Retinal Image Cause Amblyopia?

One of the main purposes of the oculomotor system is to keep the image projected on the retina stationary in spite of the continuous movement of the head. If the vestibulo-ocular and optokinetic reflexes are defective, the retinal image becomes blurred owing to the uncoordinated movements of the head and the eyes. It is well known that in children retinal blur caused by media opacities or large refraction errors results in amblyopia. In a similar way amblyopia could be caused by slip of the retinal image due to a defective oculomotor system. Our patient was a small for gestational age A-twin. He developed dystonic diplegia with poor head control. At the age of 7 months he was considered to have cortical visual impairment. In a magnetic resonance image of the brain there were diffuse periventricular changes in the white matter and hypoplasia of the corpus callosum and the cerebellar vermis. Binocular optokinetic reflexes to full-field stimuli were horizontally asymmetric and were missing vertically. The reflexes to rotation of the child were asymmetric in the same way. In order to stabilise the retinal image the head of the child was supported always when he was supposed to look at a target with fine details. Increase in visual acuity measured with a Teller acuity card procedure was apparent after head support. This suggests that retinal slip can cause amblyopia. It is usual practice not to support the head of a child who has cerebral palsy and poor head control. In the case of defective head - eye coordination this practice could be harmful to the normal development of vision.

Vision in albinism

The purpose of this investigation was to study vision in albinism from 3 perspectives: first, to determine the characteristics of grating acuity development in children with albinism; second, to study the effect of illumination on grating acuity; and third, to define the effect of melanin pigment in the macula on visual acuity.I. Binocular and monocular grating acuity was measured with the acuity card procedure in 40 children with albinism during the first 3 years of life. Recognition acuity was eventually measured in 27 of these patients. Ocular pigment was documented by a previously established method of grading iris transillumination and macular transparency. II. Grating acuity under standard and increased illumination levels was measured in 20 adults with albinism (group I) compared with that in 20 adults with nystagmus due to conditions other than albinism (group II) and 20 adults without ocular abnormalities (group III). Recognition acuity measured with the ETDRS charts was also recorded for each group. III. Best-corrected binocular acuity was measured in 29 patients with albinism who were identified with melanin pigment in their maculas by direct ophthalmoscopy.I. Both binocular and monocular grating acuity was reduced 2 to 3 octaves below the norm for ages 6 months to 3 years. Limited data available in the first 6 months of life did not show failure of vision to develop. Grating acuity measurements overestimated eventual recognition acuity. Mean recognition acuity was 20/111. A relationship between grating acuity development and presence or absence of ocular pigment was not found. II. Grating acuity was significantly better for groups I and II under the condition of increased illumination (P < .03). For patients with albinism, grating acuity under standard illumination was significantly better than recognition acuity (P < .001). For all groups, grating acuity under increased illumination was significantly better than recognition acuity (P < .01). III. Mean recognition acuity in patients with albinism and melanin pigment in their maculas (20/47) was significantly better than measured recognition acuity in Project I (P < .001). All had foveal hypoplasia, but 8 patients had an incompletely developed annular reflex in the macula, 6 patients showed stereoacuity, and 3 patients had no nystagmus.I. Grating acuity development in albinism seems to progress along a curve that is asymptotic to visual development in a normal population. II. Increasing illumination does not reduce grating acuity in patients with albinism. Grating acuity overestimates recognition acuity in these patients. III. Ophthalmoscopic detection of melanin pigment in the macula in patients with albinism is associated with better vision.

Evaluation of Methods for Assessing Visual Function of Infants † 1384

One of the reasons infants may require docosahexaenoic acid is to support normal visual development. However, the optimal method for assessing visual function of infants has not been established. To evaluate available methods, we have determined test/retest reliability of transient visual evoked responses (latency; amplitude) and acuity measured by steady-state visual evoked potentials (sweep VEP) as well as the Teller acuity card procedure and have compared results obtained with the three procedures. To determine test/retest reliability, each procedure was administered twice within 5 d to 4 mo old infants (n=20-25), using standard protocols. Comparability of findings with all possible pairs of methods was determined by regression analysis. Test/retest reliability data are summarized below:Table Although the mean difference between test and retest results is reasonably small for all methods, the 95% C.I. for individual differences is quite large. More important, there were no statistically significant correlations between findings with any pair of procedures. We conclude that all methods are valid for comparison of visual function between/among groups of infants, but that none reliably predicts visual function/acuity of an individual infant.

Vision outcome at age 2 years in a low birth weight population

We assess the prevalence of vision problems in a cohort of low birth weight infants at age 2 years and the relationship of these problems to neonatal brain injury. Data on prenatal and neonatal history and brain injury status were prospectively collected on 721 children weighing 500–2,000 gm at birth enrolled in a multicenter, population-based longitudinal study. Visual acuity was evaluated using the Teller Acuity Card Procedure. Abnormalities of the eye were assessed by a specially trained pediatric nurse practitioner. Failure of the acuity screen occurred in 62 of 699 tested (8.9%). Multiple logistic regression analysis revealed that the only significant independent predictors of failure included presence of disabling cerebral palsy (DCP) (odds ratio [OR] = 14.8) or nondisabling cerebral palsy (NDCP) (OR = 4.0) and Apgar score of less than 5 at 5 minutes (OR = 2.4). Parenchymal brain injury (PEL) was of borderline significance. Strabismus was present in 123 of 702 children (17.5%). Multiple logistic regression analysis disclosed that the joint predictors of strabismus were presence of DCP (OR = 7.2) and length of hospital stay (OR = 1.6). We conclude that low birth weight infants with parenchymal brain lesions leading to cerebral palsy are at particular risk for vision problems early in life and should be carefully evaluated.

Visual Acuity and Fatty Acid Status of Term Infants Fed Human Milk and Formulas with and without Docosahexaenoate and Arachidonate from Egg Yolk Lecithin1

Preterm infants fed formulas with docosahexaenoic acid (DHA, 22:6n-3) during the interval equivalent to the last intrauterine trimester and beyond have higher circulating DHA and transiently higher visual acuity compared with infants fed formulas containing linolenic acid. In term infants several nonrandomized studies of infants receiving DHA from human milk suggest a relationship between DHA status and acuity, but the evidence for a cause-and-effect relationship is mixed. In the present study, term infants were randomly assigned to a standard term formula (n = 20) or the same formula with egg yolk lecithin to provide DHA (0.1%) and arachidonic acid (AA, 20:4n-6, 0.43%) (n = 19) at levels reported in milk of American women. A third group of infants was breast fed for > or = 3 mo (n = 19). Grating visual acuity (Teller Acuity Card procedure) and plasma and red blood cell (RBC) phosphatidylcholine (PC) and phosphatidylethanolamine (PE) DHA and AA were determined at corrected ages of 2, 4, 6, 9 (acuity only), and 12 mo past term = 40 wk postmenstrual age (PMA). At 2 mo breast-fed infants and infants fed the supplemented formula had higher grating acuity than term infants fed standard formula. As in preterm infants, the increase was transient. Plasma PC DHA and AA and RBC PE AA increased by 2 mo in supplemented infants, but RBC PE DHA in supplemented infants was not higher than in controls until 4 mo and beyond. Despite normal intrauterine accumulation of DHA and AA, infants fed formula with 2% linolenic acid and 0.1% DHA had better 2-mo visual acuity than infants fed formula with 2% linolenic acid.

Visual Acuity of Eyes after Vitrectomy for Retinopathy of Prematurity: Follow-up at 5 1/2 Years

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).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.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.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.

Correlation between cerebral visual impairment and magnetic resonance imaging in children with neonatal encephalopathy.

To identify brain lesions most often associated with cerebral visual i mpairment (CVI) after neonatal encephalopathy and to evaluate the prognostic value of MRI for visual outcome, the authors reviewed visual assessments and brain MRI of 80 infants and young children with documented perinatal hypoxic-ischaemic and/or haemorrhagic insults. MRIs were classified according to the severity of lesions at the optic radiations and at the visual cortex; visual acuity was tested with the acuity card procedure. Among the 48 children found to have a CVI, 42 had moderate to severe lesions of the optic radiations and 19 had lesions of the visual cortex. In both cases visual acuity was statically correlated with MRI grading, but the damage at the optic radiations was the better predictor. Early detection of abnormal MR findings in the visual cortex and especially, at the optic radiations may indicate which infants with neonatal encephalopthy should receive longitudinal visual assessment and specific rehabilitation and educational management.

Early Predictors of Cerebral Visual Impairment in Infants with Cystic Leukomalacia

A longitudinal prospective follow-up study looking at the correlation between haemorrhagic-ischaemic lesions on neonatal cranial ultrasound (US) and the development of cerebral visual impairment (CVI) in infancy resulted in the detection of nine infants with severe visual impairment, which was not due to opthalmological abnormalities. Extensive cystic leukomalacia proved to be highly predictive of CVI, as well as of severe mental and motor deficit in these nine infants. The present report outlines the results of different examinations (acuity card procedure [ACP], visual evoked potential [VEPs], magnetic resonance imaging [MRI]) performed during the first 18 months, to find out which combination of examinations would be the most predictive of CVI at an early stage. The results indicated that infants with a gestational age of 35 weeks or more, who sustained extensive cystic leukomalacia during the neonatal period, and were subsequently not fixating at the acuity cards at term and at three months of age, invariably developed CVI. VEPs were also severely abnormal in the infants with the worst visual outcome, but were not providing a more reliable prognosis. Also, a good correlation between MRI-abnormalities of the optic radiations and/or the visual cortex and CVI was found, but MRI was usually performed beyond the age of 12 months.

Acceptance/Use of the Teller Acuity Card Procedure in the Clinic

The Teller Acuity Card (TAC) procedure is a simple, subjective method of assessing visual acuity in infants and children unable to be tested with standard clinical techniques. The TAC procedure was...

Haemorrhagic-ischaemic lesions of the neonatal brain: correlation between cerebral visual impairment, neurodevelopmental outcome and MRI in infancy.

The relationship between the degree of cerebral visual impairment, established using the acuity card procedure, and the extent of neurological sequelae was assessed in 65 at-risk neonates in a prospective follow-up study. MRI and CT scans were performed in all infants with severe neurological sequelae. 11 of 12 children with an acuity at or below the 10th centile at 18 months developed cerebral palsy: the underlying condition was extensive cystic leukomalacia in all. An acuity above the 10th centile was no guarantee of normal development, as 10 out of 52 such infants developed cerebral palsy. MRI and CT scans showed that periventricular high signal intensity in the occipital area was a non-specific finding with regard to visual function. Extensive periventricular white matter loss and involvement of the striate/parastriate cortex was found in the most severely visually impaired infants.

Interobserver agreement for measurement of grating acuity and interocular acuity differences with the Teller acuity card procedure

Interobserver reliability of the Teller acuity card (TAC) procedure for estimating acuity and interocular acuity differences (IADs) was assessed with 342 infants and children who had been treated in a neonatal intensive care unit for preterm birth and/or perinatal complications. Subjects were tested binocularly at term and monocularly at 4, 8, 11, 17, 24, 30, 36, and 48 months corrected age with TACs. Testers were masked to the location and spatial frequency of the grating on each card. Of the interobserver test-retest scores, 67% differed by no more than 0.5 octave, and 87% of the test pairs differed by no more than 1 octave. Of the test-retest comparisons of a subject's IAD, 54% showed agreement of 0.5 octave or better, and 76% differed by no more than 1 octave. Interobserver agreement for binocular and monocular tests was similar to that reported previously for visually and neurologically at-risk infants and children tested with the forced-choice preferential-looking procedure or with prototype acuity cards. Interobserver agreement for IAD estimates was somewhat less than that reported for a sample of infants with ocular disorders. There were no systematic differences in interobserver agreement between eyes tested first and eyes tested second, nor was interobserver agreement related to subject's medical diagnosis. Interobserver agreement was influenced, however, by the spatial frequencies of the particular gratings used during testing and, to a limited extent, by the age of the child. The duration of individual tests and observers' ratings of confidence in their acuity estimate were not reliable indicators of test-retest pairs that were not in agreement. The results demonstrate the reliability of the TAC procedure, but suggest that acuity estimates critical to a patient's diagnosis or treatment should be confirmed by repeat testing.

Development of visual acuity in relation to plasma and erythrocyte ω-6 and ω-3 fatty acids in healthy term gestation infants

The development of preferential looking acuity was studied prospectively to 3 mo of age in exclusively breast-fed and formula-fed term gestation infants. The formula contained (% of total fatty acids) 17.9% linoleic acid (18:2 omega-6) and 2.1% alpha-linolenic acid (18:3 omega-3) but no docosahexaenoic acid (22:6 omega-3) or arachidonic acid (20:4 omega-6). The breast milk contained (mean +/- SEM) 13.4 +/- 0.8% 18:2 omega-6, 1.5 +/- 0.1% 18:3 omega-3, 0.51 +/- 0.03% 20:4 omega-6, and 0.22 +/- 0.02% 22:6 omega-3. Preferential looking acuity, assessed by the acuity-card procedure, and plasma phospholipid and erythrocyte phosphatidylcholine and phosphatidylethanolamine fatty acids were determined at 14 d and 3 mo of age. There were no significant differences in acuity at 14 d or 3 mo, despite substantial differences in erythrocyte and plasma lipid 22:6 omega-3. Visual acuity was [mean (cycles/degree) +/- SD (octaves)] 3.93 +/- 0.54 and 4.77 +/- 0.48 and erythrocyte phosphatidylethanolamine %22:6 omega-3 was (mean +/- SE) 7.6 +/- 0.5 and 4.0 +/- 0.2 in the 3-mo-old breast-fed and formula-fed infants, respectively. These studies show that feeding formula containing 2.1% 18:3 omega-3 (approximately 1.0% energy) results in development of visual acuity similar to breast-feeding in term infants to > or = 3 mo of age.

60 HAEMORRHAGIC-ISCHAEMIC LESIONS OF THE NEONATAL BRAIN: CORRELATION BETWEEN CEREBRAL VISUAL IMPAIRMENT, NEURODEVELOPMENTAL OUTCOME AND MRI IN INFANCY

A group of sixty-five at-risk neonates was enrolled in a prospective follow-up study in order to assess the relationship between the degree of Cerebral Visual Impairment, established using the Acuity Card Procedure, and the extent of neurological sequelae. Furthermore, MR- and CT-scans were performed in all infants with severe neurological sequelae to study whether characteristic lesions occurred in the central visual pathway.Eleven out of twelve infants with an acuity on or below the 10th centile at 18 months developed cerebral palsy: the underlying condition was extensive cystic leukomalacia in all. However, an acuity above the 10th centile was no guarantuee for a normal development, as ten out of 52 infants developed cerebral palsy; six had a large peri/intraventriculat haemorrhage, four had cystic leukomalacia.MR- and CT-scans showed, that periventricular high signal intensity in the occipital area was found to be a non-specific finding with regards to visual function. Very extensive periventricular white matter loss and involvement of the striate/parastriate cortex was found in the most severely visually impaired infants.p.Eken was supported by the ‘praeventiefonds’ (grant no. 28-1406)

Relation between neonatal cranial ultrasound abnormalities and cerebral visual impairment in infancy.

A prospective follow-up study was conducted of a cohort of 65 at-risk neonates to assess the predictive value of neonatal cranial ultrasound abnormalities for cerebral visual impairment in infancy. Visual function was assessed using the acuity card procedure and behavioural visual responses were tested. Normal visual function was found in controls as well as in infants with small haemorrhages or mild leukomalacia. Infants with large haemorrhages performed poorly at 40 weeks postmenstrual age, but recovered to within the normal range in the first half year. In contrast, of the infants with extensive cystic leukomalacia, four of nine preterm infants and three of four term infants were severely visually impaired at 18 months. In the more mature infants, the cystic lesions extended deeper into the subcortical white matter, and this appeared to be associated with a worse visual outcome. Cystic leukomalacia proved to be highly predictive of cerebral visual impairment in infancy.

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.

The effect of grating orientation on resolution acuity in patients with nystagmus.

The acuity card procedure is an effective method for the assessment of grating acuity in preverbal and nonverbal patients. However, the effect of nystagmus on this acuity assessment has not been well-described. We studied the effect of grating orientation on the measurement of resolution acuity in a group of nystagmus patients, a group of patients with albinism and nystagmus, and a normal control group. The resolution acuity was significantly (P < or = .01) better with horizontal grating orientation in both the nystagmus and the albino groups, but grating orientation did not affect resolution acuity in the control group. This study suggests that grating orientation must be taken into account when using the acuity card procedure in patients with nystagmus.

Visual-acuity development in healthy preterm infants: effect of marine-oil supplementation

Docosahexaenoic acid (DHA; 22:6n-3) is important for normal visual development. We hypothesized that preterm infants fed formulas with marine oil as a source of DHA would have better visual acuity than infants fed formulas without marine oil, as measured by the Teller Acuity Card procedure. Marine oil (P < 0.001) and age (P < 0.0001) influenced visual acuity, by repeated-measures analysis of variance (ANOVA) corrected for the effect of subject. Marine-oil-supplemented infants had better visual acuity than those fed standard formulas at 2 and 4 mo of age, by Fishers' least-squares difference (LSD). Acuity of both dietary groups improved through 6.5 mo of age, then plateaued. Through 4 mo of age, acuity was inversely related to oxygen supplementation (log10 h) and positively related to DHA status, by general-linear-models (GLM) analysis. After 4 mo of age, birth weight and gestational age were the only variables consistently related to visual acuity by GLM. We conclude that marine-oil-supplemented formula improved visual acuity of preterm infants through 4 mo of age by improving DHA status.

The Teller Acuity Card Procedure: Three Testers in a Clinical Setting

The Teller acuity card procedure provides a quantitative measure of grating acuity in infants and young children and has been used in clinical and laboratory settings. The purpose of this study is to address the influence of the individual testers in a clinical setting. The authors report a comparison of acuity results obtained by three well-trained, experienced testers in a busy hospital-based clinical practice. Three different testers (A, B, C) performed 971 consecutive acuity assessments using the Teller acuity card procedure on 570 patients. The testers used similar techniques and adaptations, depending on clinical need. Diagnostic categories include nystagmus, aphakia, strabismus, glaucoma, retinopathy of prematurity (ROP), ptosis, optic nerve abnormalities, etc. Patients ranged in age from 2 weeks to 17 years (mean +/- standard deviation, 23 +/- 20 months). When each patient was represented only once, A tested 144 patients; B, 251; and C, 175. The geometric mean right eye acuity scores of A were 3.00 cycles/degree (cy/deg) (0.34 octaves, standard error [SE]; n = 134); B, 4.05 cy/deg (0.20 octave, SE; n = 225); and C, 3.71 cy/deg (0.30 octave, SE; n = 163). An analysis of covariance showed a significant difference in the mean log scores across testers (P = 0.02 adjusted for both age and diagnosis). Age was a strong predictor of acuity (P = 0.0001), and the interactions between tester and age and tester and diagnosis were not significant. The geometric mean left eye acuity scores for A were 2.86 cy/deg (0.33 octave, SE; n = 132); B, 3.46 cy/deg (0.23 octave, SE; n = 218); and C, 3.32 cy/deg (0.30 octave, SE; n = 160). The differences for left eyes among testers were not significant (P = 0.37 adjusted for age and diagnosis). These results suggest that the tester may influence the acuity results measured by the Teller acuity card procedure in a clinical setting. Evaluation of interobserver reliability in clinical subjects should be a high priority of further work using the Teller acuity card procedure.

Visual field and grating acuity development in low-risk preterm infants during the first 2 1/2 years after term

The effect of early visual experience on visual field size and grating acuity development was studied longitudinally in 36 appropriate for gestational age (AGA) and 26 small for gestational age (SGA) low-risk preterm infants. These were selected out of 194 very low birth weight (VLBW) infants (birthweight less than 1500 g) born in 1985 and 1986. Criteria for inclusion as low-risk were the absence of neurological, respiratory, circulatory and alimentary problems in the neonatal period; no retinopathy of prematurity and no evidence of abnormality on the neonatal cranial ultrasound scans. Binocular field sizes were assessed using kinetic arc perimetry. Binocular grating acuity was tested by means of the prototype version of the acuity card procedure. Results were compared with norms obtained in control fullterms in earlier studies. Infants were tested at 6 weeks, 6, 6, 9 and 12 months of age from the expected term date. Twenty-two of these infants were retested at 2 1/2 years of corrected age. Visual field size and visual acuity estimates of (both AGA and SGA) low-risk, VLBW preterms and control fullterms overlapped at all test ages, except for a slight but significantly faster development of the upper and the lower visual field at 6 weeks corrected age in the preterm group. These results indicate that for clinical purposes visual experience before the expected term date has not only no measurable effect on the normal development of behavioural acuity, but also no accelerating effect on the development of peripheral vision.

The prevalence of cerebral visual disturbance in children with cerebral palsy.

Assessment of visual acuity using the visual acuity card procedure in 164 children with cerebral palsy revealed low visual acuity in 71 per cent. Results of ophthalmological examination were available for 74 of these patients, but could not explain adequately the low visual acuity of 36 of the 43 patients (84 per cent) assessed by both the acuity card procedure and other techniques. There is a high probability that cerebral visual disturbance is present in these patients. Awareness of visual disability when compiling a programme of visual and neurodevelopmental stimulation for children with cerebral palsy is essential.