Acuity Cards Research Articles

Time-dependent effects on contrast sensitivity, near and distance acuity: difference in functional parameters? (Prospective, randomized pilot trial of photodynamic therapy versus full macular translocation)

To report the change of contrast sensitivity (CS) after photodynamic therapy (PDT) vs full macular translocation (FMT) for neovascular age-related macular degeneration (AMD), and to relate this to other measures of visual function (distance and near acuity). Fifty patients (50 eyes) with predominantly classic subfoveal choroidal neovascularisation (CNV) secondary to AMD were randomized to PDT or FMT. CS was measured with Pelli-Robson charts. Acuity scores of near visual function (NVS) were calculated after testing with visual acuity cards of the Swiss National Association of and for the Blind (SNAB). Best corrected distance visual acuity (DVA) was determined according to a standardized protocol with EDTRS charts. Primary end point was the change of CS at 12-month examination from baseline. The interaction of the CS with NVS and DVA was analysed. Mean CS showed a decrease in both treatment groups (FMT: -2 letters, PDT: -3 letters, p=0.969) at 12-month examination from baseline. While mean NVS improved by seven letters in the FMT group, a decrease of more than ten letters was seen in the PDT group (p<0.05). We found no agreement between CS and high-contrast acuity (NVS, DVA). In FMT patients, the parameters at baseline (CS, NVS, DVA) correlated poorly with the corresponding 12-month results, therefore providing no informative basis to predict the later functional development. In contrast, PDT patients showed strong baseline-to-outcome coherence with baseline measures also associated with better final values. Although FMT can initiate recovery of near and distance acuity over the period of 1 year in selected patients with classic CNV, CS did not differ between FMT and PDT. We found no close connection of CS with DVA or NVS, especially after FMT. Knowledge about the unequal variation of visual parameters can provide more comprehensive information when advising patients on different therapeutic options. That also applies in particular to vascular endothelial growth factor inhibitors, which seem to promise an even higher extent of gain in CS and to reach the peak of recovery at an earlier time.

Paediatric cataract surgery

Bilateral congenital cataract is the most common cause of treatable childhood blindness. Nuclear cataract is usually present at birth and is non-progressive, while lamellar cataract usually develops later and is progressive. Prompt surgery has to be performed in cases with dense congenital cataract: if nystagmus has developed, the amblyopia is unfortunately irreversible. A treatment regime based on surgery within 2 months of life, combined with prompt optical correction of the aphakia and occlusion therapy with frequent follow-up, have been successful in both unilateral and bilateral cases. The surgery ought to include anterior and posterior capsulorexis in all children at the present time. Intraocular lens implantation has been safely performed below the age of 1 year and has also been successfully performed in bilateral cases. Anterior dry vitrectomy should be performed in preschool children to avoid visual axis opacification. Visual axis opacification is the most common complication found after cataract surgery in children. Secondary glaucoma is by far the most sight-threatening complication and is, unfortunately, common in the newborn so lifelong follow-up is essential in these cases.

A visual skills inventory for children with neurological impairments

Children with neurological impairments often have visual deficits that are difficult to quantify. We have compared visual skills evaluated by carers with results of a comprehensive visual assessment. Participants were 76 children with mild to profound intellectual and/or motor impairment (33 males, 43 females; age range 7mo-16y; mean age 5y 1mo [SD 4y 2mo]) who completed a visual skills inventory before attending a special vision clinic. The inventory included 16 questions about visual skills and responses to familiar situations. Responses were augmented by taking a structured clinical history, compared with visual evoked potential (VEP) and/or acuity card measures of visual acuity, and examined using exploratory factor analysis. Acuity ranged from normal to no light perception, and was positively associated with responses to individual questions. After excluding four uninformative questions, an association between the remaining questions and two significant independent factors was found. Factor 1 was associated with questions about visual recognition (e.g. 'Does your child see a small silent toy?') and these items were correlated with both the VEP and acuity card thresholds. Factor 2 was associated primarily with questions about visually mediated social interactions (e.g. 'Does he/she return your silent smile?'). Evaluation of visual skills in children with neurological impairment can provide valid information about the quality of children's vision. Questions with the highest validity for predicting vision are identified.

Relationship between visual acuity, visual evoked patterned potentials done at different spatial frequencies and fundus findings in more than 100 Cerebral Visual Impairment affected subjects

Abstract Purpose: To analyze relationship between visual acuity (VA), visual evoked patterned potentials (VEP) and fundus state of the optic disk in children diagnosed by MR as cerebral visual impaired (CVI). Methods: Full clinical examinations, including Teller Acuity Cards (TAC) and/or optotype for decimal visual acuity, VEP and fundus optic disk findings , were done in 107 CVI affected infants (mean age 7,9±6). TAC were administered at spatial frequencies ranging from 0.23 to 38 cycles/degrees, at a distance varying from 84 to 55 cm. VEPs were recorded at Oz, O1, O2, referenced to Fz. Five black and white checks sizes, 300’,120’,60’,30’,15’, were presented. At least two spatial frequencies were performed depending upon the visual function. Statistical analysis: means and standard deviations were presented, correlation between VA and VEP, and association between optic disk features and VA were made. Results: Mean VA in decimal, was 3.55, ranging from 1.5 (p 25)to 4.8 (p 75). Percent success in TAC responses was 75. Mean VEP latencies in Oz varied from 112 ( 15’) to 105,9 ( 300’). Mean amplitudes varied from 18,8 ( 15’) to 22,3 (300’). VEP percent success was 77.6. A negative correlation coefficient ( r ) was found between VA and larger checks . A weak association was found between VA, VEP and optic disk features. Conclusions: Behavioural and objective tests correlate at different levels with fundus findings in CVI affected children, and are both useful in their follow‐up.

Predicting long-term visual outcome in children with birth weight under 1001 g

To examine the visual acuity development of extremely low birth weight children and to determine factors that are predictive of long-term outcome. This is a prospective observational longitudinal cohort study of children with birth weight less than 1001 g. One hundred thirty-nine children were recruited. Retinopathy of prematurity (ROP) examinations were graded according to the International Classification for ROP. Grating acuity was assessed monocularly with Teller acuity cards. All children were assessed before 24 months corrected age; 123 of the cohort had a grating acuity assessment at over 3 years. For the children who were capable, an assessment of recognition acuity was measured with the Electronic Visual Acuity system. Data are presented for the right eye and the ages reported are adjusted for prematurity to allow comparison with normative data. Initial grating acuity was compared with the late grating and recognition acuity, but in both cases analysis showed no statistically significant association. However, the relative risk analysis showed that, if the slope was abnormal, there was a 5.5 times higher risk of abnormal recognition acuity. Eyes with zone 1 disease were associated with a worse visual acuity outcome, but zone 1 disease also occurred more frequently in children with lower birth weight and gestational age. Early measurements of visual acuity may be misleading in terms of the visual prognosis. The factor that was most predictive of a poor late visual acuity outcome was the rate of development, as calculated by the slope of the early visual acuity measurements.

Reappraisal of Astigmatism Induced by Periocular Capillary Hemangioma and Treatment with Intralesional Corticosteroid Injection

To document refractive status and visual acuity before and after intralesional corticosteroid injection in children with astigmatism induced by periocular capillary hemangioma (PCH). Retrospective, interocular comparison, interventional case series. Thirteen infants with anisometropic astigmatism of at least 1.50 diopters (D) induced by PCH. All infants had one or more intralesional corticosteroid injections of a PCH between 2 and 10 months of age. Injections of 0.3 to 1.0 ml of a 50:50 mixture of triamcinolone (40 mg/ml) and dexamethasone phosphate (4 mg/ml) were given at a single site under deep sedation. Refraction and acuity using Teller acuity cards before and after injection. In affected eyes, mean astigmatisms were 3.75 D (pretreatment) and 1.25 D (posttreatment), and mean spherical errors were 0.75 D (pretreatment) and 1.50 D (posttreatment). Reduction in astigmatism was observed within 1 to 14 months after the injection. Despite reciprocal changes in astigmatism and spherical error, the amount of anisometropia (spherical equivalent) remained constant. Amblyopia was not observed before treatment and was observed in only 2 of 13 children after treatment. Complications were limited to adrenal suppression with transient reductions of linear growth and localized eyelid necrosis. Intralesional corticosteroid injections given in infancy (between 2 and 10 months) resulted in a 63% reduction in the mean amount of astigmatism induced by PCH. The reciprocal changes of astigmatism and spherical error without changes in anisometropia suggest that the treatment effect was due to restoration of the spherical shape of the cornea. Before 3 years of age, visual immaturity exceeded the optical blur related to astigmatism induced by PCH. Therefore, astigmatism, not anisometropia or amblyopia, is the immediate indication for treatment of PCH with intralesional corticosteroids. Injection of corticosteroid at a single site minimizes the potential for severe ocular complications owing to tissue pressure and tumor volume considerations.

Estimation of strabismic amblyopia by small-sized concentric gratings in preverbal children

Evaluate the ability to assess strabismic amblyopia of small-sized Concentric Gratings in comparison with classic linear gratings preferential looking test. Thirty-three preverbal children (age 6-30 months) with esotropia were tested for monocular visual acuity, using small-sized Concentric Gratings (target size 1.6, in 1/3 octave steps) and the Teller Acuity Cards. A fixation preference testing score was also obtained. In 17 of these children, 1-3 years later, after treatment of amblyopia and strabismus, fixation preference testing score, and visual acuity with Teller Acuity Cards, Concentric Gratings, and Glasgow Acuity Cards were measured. In 24 additional verbal untreated strabismic children (age 39-48 months), the same procedures were used. Correlations between interocular acuity difference of each preferential looking test and the Glasgow Acuity Cards were compared. Correlations between interocular acuity difference of each preferential looking procedure and fixation preference testing score were also compared. Concentric Gratings procedure was correlated significantly better than Teller Acuity Cards with fixation preference testing score (0.7 and 0.49, respectively), in the preverbal group (P=0.04). In treated verbal children, correlation of Concentric Gratings and Glasgow Acuity Cards (0.90) was stronger (P=0.06) than correlation of Teller Acuity Cards and Glasgow Acuity Cards (0.64). In untreated verbal children, correlation of Concentric Gratings and Glasgow Acuity Cards (0.89) was stronger (P=0.045) than correlation of Teller Acuity Cards and Glasgow Acuity Cards (0.67). The small-sized Concentric Gratings procedure improves detection and estimation of amblyopia depth in strabismus when compared with classic linear gratings.

Visual dysfunctions and ocular disorders in children with developmental delay. I. prevalence, diagnoses and aetiology of visual impairment

To describe the prevalence, diagnoses and aetiologies of visual impairment in children with developmental delay (DD) in a Danish county with a population of 618 000 citizens. We carried out a cross-sectional study in Copenhagen County of children aged 4-15 years with profound to borderline DD (IQ <or= 80). Children were located through school psychologists or paediatric clinics. The number of children with DD was estimated using the capture-recapture method. A total of 1126 children fulfilled the inclusion criteria, corresponding to 97.7% of the estimated number of children with DD in the county. Ophthalmological examinations were performed in 923 children. The prevalence of visual impairment was 10.5% in the study group and 22.4% in those with an IQ <or= 50. The diagnoses were predominantly cerebral visual impairment, optic atrophy, retinal dystrophies and congenital nystagmus. The aetiology of visual impairment was prenatal in 54 children, perinatal in 29 children and postnatal in seven children. Visual impairment is highly increased in children with DD and is correlated to low IQ.

A Docosahexaenoic Acid‐Functional Food During Pregnancy Benefits Infant Visual Acuity at Four but not Six Months of Age

Within the visual system, docosahexaenoic acid (DHA, 22:6n-3) is an important structural component for retinal photoreceptors and cortical gray matter. There is a marked decrease in neural DHA accumulation in the face of DHA deficiency. DHA is accumulated at an accelerated rate during pregnancy, especially in the third trimester. However, pregnant women in the US and Canada have dietary DHA intakes that are significantly below the optimal level. The main objective of this study was to determine whether a DHA-functional food during pregnancy would benefit infant visual acuity at four and six months of age measured behaviorally using the acuity card procedure (ACP). In a randomized, longitudinal, double-blinded, and placebo-controlled trial, 30 pregnant women received either the DHA-functional food (n = 16) or the placebo (n = 14). There were significant main effects for visual acuity at four months of age (P = 0.018). The mean acuity scores were 3.8 +/- 1.1 cycles/degree in the DHA group versus 3.2 +/- 0.7 cycles/degree in the placebo group. At six months there were no group differences. Based on our results, we conclude that DHA supplemented during pregnancy plays a role in the maturation of the visual system.

Teller Acuity Card norms with and without use of a testing stage

To determine whether norms obtained using the Teller Acuity Card stage are appropriate for comparison with results obtained when the stage is not used. Eighty children were tested, 20 each at 3.5, 11, 17, and 30 months of age. Binocular grating acuity was measured once with Teller Acuity Cards presented with the stage and once without the stage. Test order was counterbalanced across subjects. Testers were aware that gratings progressed from lower to higher spatial frequencies, but were masked to the absolute spatial frequency of the grating on each card. Testers were masked to acuity results until the child completed testing. Repeated measures ANOVA with age as a between-subjects variable and test setting as a within-subjects variable showed a significant effect of age (p < 0.001) and test setting (p < 0.001), and a significant interaction between age and test setting (p < 0.01). Post-hoc comparisons (with Bonferroni correction) showed that the difference in acuity results obtained with the stage versus without the stage was significant at 17 months (p < 0.05), but not at 3.5, 11, or 30 months. Grating acuity norms obtained with the Teller Acuity Card stage are appropriate for comparison with data obtained without the stage in children 3.5, 11, and 30 months of age. However, when 17-month-old children are tested without the stage, comparison of results with norms obtained with the stage is problematic, because testing without the stage results in reduced acuity scores in this age group.

Prevalência de astigmatismo refracional e sua relação com a acuidade visual de resolução em crianças de 2 a 36 meses

To evaluate refractional astigmatism prevalence and its relationship with grating acuity in a cohort of non-verbal children. 482 normal children, aged from 2 to 36 months, were submitted to ophthalmological examination. Fourteen subjects were excluded due to ocular disease and the sample remained with 468 subjects (936 eyes); 230 (49%) males e 238 (51%) females. Grating acuity was assessed binocularly and monocularly with Teller acuity cards. All children underwent eye examination including cycloplegic retinoscopy and fundus by indirect ophthalmoscopy. Astigmatism was found in 222 (47.43%) of the children, with the hyperopic and with the rule types most frequently found in all ages. Concerning magnitude, this condition was equal or greater than 1.00 cylindric diopter in 24.35% of the children; equal or greater than 2.00 cylindric diopter in 5.55%; lower than 1.00 in 26.92% and between 1.00 and 2.00 in 18.73%. Grating acuity was normal in 219 of the subjects, despite magnitude, type and orientation of astigmatism. Visual acuity assessed by the acuity card procedure was not influenced by astigmatism.

Visual and binocular status of Down syndrome children in Malaysia

Background: Down syndrome is a common chromosomal anomaly. Few reported studies make reference to the ocular status in Asian children with Down syndrome. The purpose of this study was to determine the visual and binocular status of a sample of Down syndrome children in Malaysia.Methods: A total of 73 Malaysian children with Down syndrome (38 boys and 35 girls) in the Kuala Lumpur area aged one to 12 years were examined. Cycloplegic refraction was performed on each eye and binocular visual acuity was assessed using the Cardiff acuity card or the LogMAR chart. Binocular functions were assessed using the cover test and Lang's stereo acuity test.Results: The mean age of the subjects was 6.01 ± 3.41 years. Refraction of the right eye showed that 10 per cent of the subjects were myopic, 20 per cent were hyperopic and 70 per cent had no significant refractive error. The mean spherical equivalent was +0.92 ± 2.32 DS for the right eye and +0.99 ± 2.21 DS for the left. The mean of binocular LogMAR VA was 0.36 ± 0.22 (6/12). Cover test revealed that 21 subjects had strabismus (of those, 33 per cent had unilateral esotropia, 52 per cent had alternating esotropia, nine per cent had unilateral exotropia and five per cent had alternating exotropia). Only 22 subjects gave clear positive response to the stereotest. Other ocular findings included ptosis (one per cent), abnormal head posture (seven per cent) and nystagmus (six per cent).Conclusion: Malaysian children with Down syndrome have a high incidence of refractive error and strabismus. Regular visual examination is important so that corrective lenses can be prescribed to improve vision and to enhance the quality of life of these children in Malaysia.

Accuracy of the Contrast Sensitivity Card Test for Infants: Retest Variability and Prediction of Spatial Resolution

We assessed the retest variability of a new contrast sensitivity (CS) card procedure and its ability to predict spatial resolution. Twenty-four 3-month-olds were tested twice with the CS cards and once with the Teller acuity cards (TAC) within a single session. Coefficient of repeatability (COR) analysis revealed that retest variability of the new cards is superior to that of an earlier prototype at low to mid spatial frequencies. Furthermore, retest variability is comparable to that of infant visual evoked potential studies and the Vistech 6500, a chart commonly used to measure CS in adults. Finally, estimates of visual acuity based on the CS cards were consistent with those provided by the TAC (although CS-based estimates were generally lower overall). Given its reliability and accuracy, the new CS card procedure has good potential as a clinical tool for assessing spatial vision in infants and toddlers.

Visual Acuity Development After the Implantation of Unilateral Intraocular Lenses in Infants and Young Children

Intraocular lenses (IOLs) are now being implanted in infants and children with unilateral cataracts. However, there are no prospective data on the development of visual acuity after implantation. The aim of the present study was to prospectively assess the development of acuity in infants and preschool children who received IOLs or aphakic contacts lenses (CLs) after the extraction of a unilateral cataract. Visual acuity was assessed using Teller Acuity Cards and/or crowded HOTV tests at target ages of 6 months, 1, 2, 3, and 4 years. Infants who received a primary IOL after extraction of dense congenital unilateral cataract (n = 5) showed improvement from an initially low mean visual acuity of 20/170 at 6 months to 20/85 at 12 months and 20/54 at 4 years. Visual acuity in the IOL group was similar to that of children who had good-to-excellent compliance with CL wear (n = 36; 4-year visual acuity 20/50) and better than that of children who had moderate-to-poor compliance (n = 11; 4-year visual acuity 20/135). Children who received IOLs after extraction of developmental unilateral cataracts by 6 months (n = 4; 4-year visual acuity 20/55) had visual acuity development similar to those treated with CLs (n = 5; 4-year visual acuity 20/55). Children who received IOLs after extraction of developmental unilateral cataracts after 1 year of age (n = 18) had better visual acuity than children those treated with CLs (n = 4) at 4 years of age (20/40 vs. 20/135). IOLs and aphakic CLs support similar visual acuity development after surgery for a unilateral cataract. IOLs may support better visual acuity development when compliance with CL wear is moderate to poor or when a cataract is extracted after 1 year of age.

Are Norms Based on the Original Teller Acuity Cards Appropriate for Use with the New Teller Acuity Cards II?

We sought to compare visual acuity results obtained with the original Teller Acuity Cards (TAC), which are no longer commercially available, and the modified, laminated Teller Acuity Cards II (TAC II), which recently became commercially available. Sixty children were tested, 20 at each of 3 ages: 3.5 months, 11 months, and 30 months. Each subject's binocular grating acuity was measured once with the TAC and once with the TAC II, with the order of testing counterbalanced across subjects. Testers were aware that acuity cards were arranged in ascending order of spatial frequency, but they were masked to the absolute spatial frequencies of the gratings in the subset of cards used. Testers were also masked to acuity results until testing of the child was completed. Repeated-measures analysis of variance with age as a between-subjects variable and card type as a within-subjects variable showed a significant effect of age (P < 0.001) and a significant effect of card type (P < 0.001), but no interaction between age and card type. Post hoc comparisons (with Bonferroni correction) showed that mean acuity score was significantly better with TAC than with TAC II at 3.5 months (0.2 octave, P < 0.05), 11 months (0.4 octave, P < 0.01), and 30 months (0.7 octave, P < 0.001). These results suggest that normative grating acuity data obtained with the original Teller Acuity Cards need to be adjusted toward lower acuity values by approximately 0.5 octave to be appropriate for use with the new Teller Acuity Cards II.

Effects of Prenatal Alcohol Exposure on Infant Visual Acuity

To examine the effects of prenatal alcohol exposure ascertained prospectively on infant visual acuity across a range of exposures and factors that mediate or moderate these effects. Infant visual acuity was examined in 131 Cape Coloured (mixed ancestry) maternal-infant pairs in Cape Town, South Africa. Drinking patterns were documented by maternal reporting during pregnancy. Grating acuity was assessed with Teller Acuity Cards (TAC) at 6.5 months after term. Data were analyzed by correlation, multiple regression, and analysis of variance. Greater average daily prenatal alcohol exposure was related to poorer acuity, as indicated by lower TAC scores. The effect of alcohol on acuity was significant primarily for infants born to mothers > or =30 years of age at delivery, in comparison to infants born to younger mothers. This effect was not mediated by gestational age or birth size or attributable to alcohol-related neurocognitive deficits. This study linked prenatal alcohol exposure ascertained prospectively to poorer visual acuity in infancy. The results are consistent with clinical and animal evidence of alcohol-related disruption of the visual system.

Visual acuity and behavior in people with severe motor and intellectual disabilities

The authors examined the relationship between visual acuity and daily behavior in people with severe motor and intellectual disabilities (SMIDs). The visual acuity of 15 subjects was assessed using two methods: Teller Acuity Cards and the STYCAR balls vision test. The subjects' caregivers evaluated the subjects' daily behavior and completed a questionnaire. Results implied that visual acuity and behavior were correlated.

Visual Acuity in Premature Infants

Purpose: To measure grating visual acuity in premature infants and compare it with that in full-term infants. Methods: The visual acuity of 73 premature and 73 full-term infants was tested at 6 months of age by the Teller Acuity Card procedure. All premature infants had undergone indirect funduscopy for the detection of retinopathy of prematurity (ROP). Seven infants had developed ROP. The mean gestational age of the premature infants was 33 ± 1.4 weeks as compared with 39.9 ± 0.9 weeks in the full-term infants. The mean birth weights of the 2 groups were 1,906 ± 412 and 3,244 ± 420 g, respectively. Results: Impaired binocular visual acuity was found in 53.4% of the premature infants, but in only 11% of the full-term infants (p < 0.0001). Impaired monocular visual acuity was found in 13.7% of the premature infants as compared with 2.7% of the full-term infants. Within the premature infant group, monocular visual acuity was impaired in 42.9% of those with ROP and in 10.6% of those without ROP (p = 0.0497). Pathological refraction was found in 33.3% of the prematures without ROP and in 14.3% of the prematures with ROP. This difference was not statistically significant. Visual acuity of preterm infants was not different from full-term infants when examined at 6 months of postconceptual age. Conclusions: Both monocular and binocular visual acuities as measured by the Teller Acuity Cards are worse in premature infants than in full-term infants at the same chronological age. Poor visual acuity in premature infants can be attributed mainly to immaturity of the visual system.

Is exposure to cocaine or cigarette smoke during pregnancy associated with infant visual abnormalities?

The aim of this study was to assess the association between cocaine or cigarette smoke exposure in utero and visual outcome. A total of 153 healthy infants (89 males, 64 females; gestational age range 34 to 42 weeks) were prospectively enrolled in a masked, race‐matched study. Quantitative analyses of urine and meconium were used to document exposure to cigarette smoke and cocaine. Infants with exposure to other illicit drugs, excepting marijuana, were excluded. At 6 weeks of age, grating acuity and visual system abnormalities (VSA; eyelid oedema, gaze abnormalities, and visual inattention) of 96 infants from the original study sample were assessed with the Teller acuity card procedure and a detailed neurological examination. Neither cocaine nor cigarette smoke exposure was associated with acuity or VSA. However, VSAs were associated with abnormal neurological examination, independent of drug exposure and other risk factors (odds ratio 7.9; 95% confidence interval 2.0 to 31.5; p=0.004). This unexpected finding could prove a helpful clinical marker for the infant at risk for neurological abnormalities.

Is exposure to cocaine or cigarette smoke during pregnancy associated with infant visual abnormalities?

The aim of this study was to assess the association between cocaine or cigarette smoke exposure in utero and visual outcome. A total of 153 healthy infants (89 males, 64 females; gestational age range 34 to 42 weeks) were prospectively enrolled in a masked, race-matched study. Quantitative analyses of urine and meconium were used to document exposure to cigarette smoke and cocaine. Infants with exposure to other illicit drugs, excepting marijuana, were excluded. At 6 weeks of age, grating acuity and visual system abnormalities (VSA; eyelid oedema, gaze abnormalities, and visual inattention) of 96 infants from the original study sample were assessed with the Teller acuity card procedure and a detailed neurological examination. Neither cocaine nor cigarette smoke exposure was associated with acuity or VSA. However, VSAs were associated with abnormal neurological examination, independent of drug exposure and other risk factors (odds ratio 7.9; 95% confidence interval 2.0 to 31.5;p=0.004). This unexpected finding could prove a helpful clinical marker for the infant at risk for neurological abnormalities.