- Email: [email protected]
The LEA Grating Test in assessing detection grating acuity in normal infants less than 4 months of age
The LEA Grating Test in assessing detection grating acuity in normal infants less than 4 months of age Giovana Martini, MS, Abimael A. Netto, PhD, Andr e M. Morcillo, PhD, Heloisa G. R. G. Gagliardo, PhD, and Denise F. de Oliveira, PhD PURPOSE
To assess binocular detection grating acuity using the LEA GRATINGS test to establish age-related norms in healthy infants during their first 3 months of life.
METHOD
In this prospective, longitudinal study of healthy infants with clear red reflex at birth, responses to gratings were measured at 1, 2, and 3 months of age using LEA gratings at a distance of 28 cm. The results were recorded as detection grating acuity values, which were arranged in frequency tables and converted to a one-octave scale for statistical analysis. For the repeated measurements, analysis of variance (ANOVA) was used to compare the detection grating acuity results between ages.
RESULTS
A total of 133 infants were included. The binocular responses to gratings showed development toward higher mean values and spatial frequencies, ranging from 0.55 0.70 cycles per degree (cpd), or 1.74 0.21 logMAR, in month 1 to 3.11 0.54 cpd, or 0.98 0.16 logMAR, in month 3. Repeated ANOVA indicated differences among grating acuity values in the three age groups.
CONCLUSIONS
The LEA GRATINGS test allowed assessment of detection grating acuity and its development in a cohort of healthy infants during their first 3 months of life. ( J AAPOS 2014;18: 563-566)
T
he first year of life is critical for the development of visual function. Deprivation of adequate stimuli during this period can result in permanent visual loss.1 Grating acuity can be evaluated during the first year of life by means of a preferential looking test to assess the infant’s ability to detect gratings. In preverbal children, this measure is generally based on the child’s ability to resolve stripes or checkerboard patterns,2,3 a visual task called grating resolution acuity. The response provides a measure of the child’s ability to detect difference between the gray surface and the grating. The purpose of this study was to assess binocular detection grating acuity using the LEA GRATINGS test (Good -Lite, Elgin, IL) to establish agerelated norms in healthy infants during their first 3 months of life.
Subjects and Method This prospective, longitudinal study adhered to the tenets of the declaration of Helsinki and was approved by the Author affiliations: School of Medical Sciences, University of Campinas FCM— UNICAMP, Campinas, Brazil Submitted December 22, 2013. Revision accepted August 7, 2014. Published online November 12, 2014. Correspondence: Giovana Martini, MS, Rua Pedro Gonc¸ alves, 630, Apt. 71, Indaiatuba, SP, 13330-210 Brazil (email: [email protected]). Copyright Ó 2014 by the American Association for Pediatric Ophthalmology and Strabismus. 1091-8531/$36.00 http://dx.doi.org/10.1016/j.jaapos.2014.08.006
Journal of AAPOS
Research Ethics Committee of the University of Campinas FCM—UNICAMP, Campinas, Brazil. Infants examined at the School of Medical Sciences from January to October 2008 who met the following criteria were included: born at full-term and generally healthy, with no congenital malformations, infections, or abnormal perinatal events; weight and length appropriate for gestational age; clear red reflex at birth; and 1 month of age at the start of the study. All subjects were residents of the Campinas metropolitan region. Parents or legal guardians of included subjects provided written consent. Patients who missed one of the evaluations during follow-up before 3 months of age and those in whom visual disorders were detected during ophthalmological evaluation at 12 months of age were excluded. The LEA GRATINGS test, developed by Lea Hyv€arinen,4,5 measures detection grating acuity using four paddles, three with gratings on both sides and one with gray surface (Figure 1). The frequency of gratings is defined as cycles per centimeter (cpcm) on the surface of the paddles. Assessment was performed in a room with a luminance of 120-360 lux. Infants were held on their mothers’ laps at a distance of 28 cm from the test. The paddles were organized on a table with low spatial frequencies (wide stripes) on top.4 The gray surface and the grating were presented to the subject and were kept motionless. The response was based on observing the shift of fixation to the grating during binocular measurements. If an infant’s condition prevented measurement, the evaluation was rescheduled. All
563
564
Martini et al
Volume 18 Number 6 / December 2014 three different ages, analysis of variance (ANOVA)9 was used for repeated measures. The profile test by contrasts9 was used to locate differences at different ages.
Results
FIG 1. LEA GRATINGS.
FIG 2. Positive response of the infant.
examinations were performed by one evaluator. The grating detection thresholds were defined as the spatial frequency of the finest grating that resulted in two positive responses (Figure 2). Each subject was evaluated three times, at the end of the first, second, and third month of age. At 12 months of age, children were examined by an ophthalmologist, who performed a clinical evaluation comprising red reflex testing, Hirschberg test, cover test, assessment of ocular motor functions, retinoscopy, biomicroscopy, objective refraction, and dilated fundus examination. Infants diagnosed with ophthalmological abnormalities were excluded. Data related to the infants’ birth conditions were obtained from the newborn’s health card and the data recorded on the evaluation protocols were transcribed and stored in the database of SPSS 16.0 (SPSS Inc, Chicago, IL).6 The data were represented in a frequency distribution as cycles per degree (cpd) and logMAR values. The technique presented in the manual of Teller Acuity Cards7 and in the study by Salom~ao and Ventura 8 were used to determine the means and standard deviations of the cpd values. The data in cpd were converted into a oneoctave scale for statistical analysis and data organization, that is, the cpd values were subjected to logarithmic transformation. Acuity values was reconverted into cpd values for presentation of results. Standard deviations are presented in octaves. For comparison of grating acuity values at the
The first examination, at the end of month 1, included 386 infants; the second, at the end of month 2, 253 infants; and the third, at the end of month 3, 178 infants. Of the 178, 11 were excluded for exceeding the age of 3 months. Thus 167 infants completed the longitudinal follow-up during the first 3 months of life. At the age of 12 months, only 145 children were available for the ophthalmologic evaluation. Of these, 8 were excluded because of incomplete examination, 1 for retinoblastoma, and 3 for constant strabismus, leaving a total of 133 infants (65 males [49%]). Considering an 8% margin of error the number of cases (N) for the present study was 133 infants. The mean gestational age was 39.33 1.12 weeks (range, 37 weeks to 41 weeks and 6 days). The mean birth weight was 3515 387.4 g (range, 2215–4065 g). The Apgar index was $7 in 95.5% of cases during the first minute and 100% during the fifth minute. The racial distribution of infants was as follows: 71 (53.4%), white; 35 (26.3%), black; and 6 (4.5%), other. The records of 21 infants (15.8%) did not provide demographic data. In the first month, the mean age at the time of testing was 39.3 4.0 days (range, 19-45 days); in the second month, 71.6 3.8 days (range, 57-75 days); and in the third month, 102.3 3.6 days (range, 90-105 days). Measurements were taken within 15 days of the exact age of 1, 2, or 3 months. According to the data shown in Tables 1 and 2, binocular responses to gratings showed development toward higher mean values and spatial frequencies. At the age of 1 month, the mean grating acuity was 0.55 0.70 cpd (1.74 0.21 logMAR); at 2 months, 1.35 0.69 cpd (1.35 0.21 logMAR), and at 3 months, 3.11 0.54 (0.98 0.16 logMAR). ANOVA performed on the repeated measurements (at the ages of 1, 2, and 3 months) demonstrated the influence of age on the values (P\ 0.0001); the profile test9 showed significant differences between values at each age. A curve depicting the development of the mean of detection grating acuity was constructed based on the mean values and respective standard deviations obtained for each age group (Figure 3).
Discussion The present study represents the first attempt to determine prospectively a curve of normal development of detection grating acuity from a large cohort of normal infants evaluated longitudinally in the first 3 months of life by the LEA GRATINGS test. The improvement of infants’ ability to detect gratings observed in the present study is similar to findings in other studies using
Journal of AAPOS
Volume 18 Number 6 / December 2014
Martini et al
565
Table 1. Detection grating acuity values (cpd and logMAR) during the first 3 months of life (N 5 133) 0.25, cpd 2.08, logMAR
0.50, cpd 1.78, logMAR
1.00, cpd 1.48, logMAR
2.00, cpd 1.18, logMAR
4.00, cpd 0.88, logMAR
Frequency
f
%
f
%
f
%
f
%
f
%
Month 1 Month 2 Month 3
23
17.3
70 6
52.6 4.5
38 74 4
28.5 55.6 3.0
2 43 40
1.5 32.3 30.1
10 89
7.5 66.9
Cpd, cycles per degree; logMAR, logarithm of the minimum angle of resolution.
Table 2. Mean values of detection grating acuity (N 5 133) Evaluation Month 1 Month 2 Month 3
Mean, cpd
Mean 1.96 SD, cpd
Mean, logMAR
Mean 1.96 SD, logMAR
0.55 1.35 3.11
0.21; 1.44 0.51; 3.52 1.50; 6.56
1.74 1.35 0.98
1.32; 2.16 0.93; 1.77 0.66; 1.30
Cpd, cycles per degree; logMAR, logarithm of the minimum angle of resolution.
FIG 3. Improvement in the detection grating acuity values during the first 3 months of life in CPD and logMAR.
psychophysical or electrophysiological evaluation methodologies during the first 6-12 months of life.2,10 To our knowledge, only 2 previous studies5,11 used the LEA GRATINGS test; however, although LEA gratings have a strong correlation both with Teller Acuity Cards5 and Cardiff acuity cards,11 the results of these studies were not compared with those of the current study because of differences in methodology and age groups. Nevertheless, the results for the three age groups in the current study are similar to those of studies that used the forced-choice preferential looking technique 1 month of age.12,13 Other studies that measured infant visual acuity from birth to 28 days of life also found similar mean values.1416 Values measured during the second month of life17 are close to the corresponding values of the current study;
Journal of AAPOS
binocular values measured at the age of 3 months18 were slightly lower than ours. In their study of normal values for the Teller Acuity Cards, Salom~ao and Ventura8 reported mean acuity was 0.66 cpd at 15 days of age, 2.02 cpd at 2 months, and 3.89 cpd at 3 months—similar to values obtained in the present study. All values of the present study are within the normal values presented in the utilization manual of the test of Teller Acuity Cards (TAC- II; Stereo Optical Co Inc, Chicago, IL).7,8,14 In newborns, measured grating acuity values are strongly affected by the infant’s state of wakefulness. The challenge with this population is obtaining monocular measurements, given that occlusion can further affect infant cooperation. A large improvement in the value might mean that during the previous measurement the infant was not as awake as during the follow-up visit. On the other hand, if the follow-up measurement results in the same or a lower value than the previous measurement, it is wise to repeat the measurement the same day or within a week to confirm that the values are improving normally. Although the binocular values of a single measurement are relevant in infant assessment in the first months of life, it is more important to verify that the values obtained in follow-up tend to grow and remain within the normal range. The American Academy of Pediatrics, the American Association for Pediatric Ophthalmology and Strabismus, and the American Academy of Ophthalmology recommend that visual functions and functioning should be assessed early.19,20 Detection grating acuity is an easy and quick measurement to monitor development of visual functions. Repeated observations on how infants reach the developmental milestones in visual communication and interaction and use vision in motor development are important clinical observations on the development of brain functions. Although the lack of monocular values is a limitation of this study, the binocular measurements provided valuable data on the visual development of infants. Used in conjunction with standard clinical examination techniques, the LEA GRATINGS test provides an easy way to monitor development of visual function in infants.
Literature Search PubMed was searched on November 20, 2012, without date or language restrictions, using the following terms:
566
Martini et al
Volume 18 Number 6 / December 2014
visual acuity, eye health, vision tests, infant care, vision disorders–prevention AND control.
Acknowledgments The authors thank the medical residents and staff of the Ambulatory Service of Ophthalmology of the University of Campinas Clinical Hospital for their collaboration in the evaluation of infants. Special thanks to Dr. Lea Hyv€arinen for her contribution to the realization of this work. We acknowledge the support of the professional staff of the DAANE program (Neonatal Detection of Audiological Alterations) and the important role of the faculty and staff of the Center for Studies and Research on Rehabilitation “Prof. Dr. Gabriel Porto” (CEPRE) of the University of Campinas. References 1. Kaas JH, Jain N. Neural plasticity. In: Wong-Rilley, ed. Neuroscience Secrets. Philadelphia: Hanley and Belfus Inc; 2000:373-83. 2. Costa MF, Oliveira AGF, Bergamasco NHP, Ventura DF. Medidas psicofısicas e eletrofisiol ogicas da func¸~ao visual do recem nascido: uma revis~ao. Psicol USP 2006;17:15-33. 3. Hyv€arinen L, Jacob N. What and how does this child see? Helsinki (Finland): Vistest Ltd 2011;33-8. 4. http://www.lea-test.fi/index.html?start5en/vistests/instruct/leagrati/ leagrati.html. Accessed December 8, 2007. 5. Yudcovitch L, Linden ME, Maeda J, Shore N. An evaluation of infant visual acuity using Lea Grating Paddles e Teller Acuity Cards. J Optom Vis Dev 2004;35:224-9. 6. Statistical Package for Social Sciences for Personal Computer for Windows. Base System User’s Guide, Release 6.0. United States of America: SPSS Inc.; 2003:365. 7. Teller DY, Dobson V, Mayer L. Teller Acuity Cards—II Handbook. Vistech Consultants Inc, Dayton Ohio 2005. 8. Salom~ao SR, Ventura DF. Large-sample population age norms for visual acuities obtained with Vistech-Teller acuity cards. Invest Ophthalmol Vis Sci 1995;36:657-70. 9. Montgomery DC. Design and Analysis of Experiments. 3rd ed. New York: John Wiley & Sons; 1991.
10. Norcia AM, Tyler CW, Hamer RD. Development of contrast sensitivity in the human infant. Vision Res 1990;30:1475-86. 11. Mody KH, Kothari MT, Sil A, Doshi P, Walinjkar JA, Chatterjee D. Comparison of Lea gratings with Cardiff acuity cards for vision testing of preverbal children. Indian J Ophthalmol 2012;60:541-3. 12. McDonald MA, Dobson V, Sebris SL, Baitch L, Varner D, Teller DY. The acuity card procedure: A rapid test of infant acuity. Invest Ophthalmol Vis Sci 1985;26:1158-62. 13. van Hof-van Duin J, Mohn G. The development of visual acuity in normal fullterm and preterm infants. Vision Res 1986;26:909-16. 14. Courage ML, Adams RJ. Visual acuity assessment from birth to three years using the acuity card procedure: cross-section and longitudinal samples. Optom Vis Sci 1990;67:713-18. 15. Dobson V, Schwartz TL, Sandstrom DJ, Michel L. Binocular visual acuity in neonates: The acuity card procedure. Dev Med Child Neurol 1987;29:199-206. 16. Brown AM, Yamamoto M. Visual acuity in newborn and preterm infants measured with grating acuity cards. Am J Ophthalmol 1986;102: 245-53. 17. Mayer DL, Dobson V. Grating Acuity Cards: Validity and Reliability in Studies of Human Visual Development. Dev Brain Behav 1997;253-88. 18. Heersema DJ, Van Hof-van Duin J. Age norms for visual acuity in toddlers using acuity card procedure. Clin Vis Scin 1990;5:167-74. 19. American Academy of Pediatrics, Committee on Practice and Ambulatory Medicine and Section on Ophthalmology, American Association of Certified Orthoptists, American Association for Pediatric Ophthalmology and Strabismus, American Academy of Ophthalmology. Policy Statement. Organizational principles to guide and define the child health care system and/or improve the health of all children eye examination in infants, children, and young adults by pediatricians. Eye Examination in Infants, Children, and Young Adults by Pediatricians. Pediatrics 2003;111:902-7. 20. American Academy of Pediatrics Section on Ophthalmology and Committee on Practice and Ambulatory, American Academy of Ophthalmology, American Association for Pediatric Ophthalmology and Strabismus, and American Association of Certified Orthoptists. Instrument-Based Pediatric Vision Screening Policy Statement. Pediatrics 2012;130:983-6.
An Eye on the Arts—the Arts on the Eye
We don’t close our eyes to the Universe and then complain: “It’s dark”. We keep our eyes wide open, knowing that the light could lead us to do undreamed of things. That is all part of love. —Paulo Coelho, Manuscript Found in Accra (New York: Alfred A. Knopf, 2013), 78. Contributed by Alex V. Levin, MD, MHSc, Philadelphia, Pennsylvania
Journal of AAPOS
To assess binocular detection grating acuity using the LEA GRATINGS test to establish age-related norms in healthy infants during their first 3 months of life.
METHOD
In this prospective, longitudinal study of healthy infants with clear red reflex at birth, responses to gratings were measured at 1, 2, and 3 months of age using LEA gratings at a distance of 28 cm. The results were recorded as detection grating acuity values, which were arranged in frequency tables and converted to a one-octave scale for statistical analysis. For the repeated measurements, analysis of variance (ANOVA) was used to compare the detection grating acuity results between ages.
RESULTS
A total of 133 infants were included. The binocular responses to gratings showed development toward higher mean values and spatial frequencies, ranging from 0.55 0.70 cycles per degree (cpd), or 1.74 0.21 logMAR, in month 1 to 3.11 0.54 cpd, or 0.98 0.16 logMAR, in month 3. Repeated ANOVA indicated differences among grating acuity values in the three age groups.
CONCLUSIONS
The LEA GRATINGS test allowed assessment of detection grating acuity and its development in a cohort of healthy infants during their first 3 months of life. ( J AAPOS 2014;18: 563-566)
T
he first year of life is critical for the development of visual function. Deprivation of adequate stimuli during this period can result in permanent visual loss.1 Grating acuity can be evaluated during the first year of life by means of a preferential looking test to assess the infant’s ability to detect gratings. In preverbal children, this measure is generally based on the child’s ability to resolve stripes or checkerboard patterns,2,3 a visual task called grating resolution acuity. The response provides a measure of the child’s ability to detect difference between the gray surface and the grating. The purpose of this study was to assess binocular detection grating acuity using the LEA GRATINGS test (Good -Lite, Elgin, IL) to establish agerelated norms in healthy infants during their first 3 months of life.
Subjects and Method This prospective, longitudinal study adhered to the tenets of the declaration of Helsinki and was approved by the Author affiliations: School of Medical Sciences, University of Campinas FCM— UNICAMP, Campinas, Brazil Submitted December 22, 2013. Revision accepted August 7, 2014. Published online November 12, 2014. Correspondence: Giovana Martini, MS, Rua Pedro Gonc¸ alves, 630, Apt. 71, Indaiatuba, SP, 13330-210 Brazil (email: [email protected]). Copyright Ó 2014 by the American Association for Pediatric Ophthalmology and Strabismus. 1091-8531/$36.00 http://dx.doi.org/10.1016/j.jaapos.2014.08.006
Journal of AAPOS
Research Ethics Committee of the University of Campinas FCM—UNICAMP, Campinas, Brazil. Infants examined at the School of Medical Sciences from January to October 2008 who met the following criteria were included: born at full-term and generally healthy, with no congenital malformations, infections, or abnormal perinatal events; weight and length appropriate for gestational age; clear red reflex at birth; and 1 month of age at the start of the study. All subjects were residents of the Campinas metropolitan region. Parents or legal guardians of included subjects provided written consent. Patients who missed one of the evaluations during follow-up before 3 months of age and those in whom visual disorders were detected during ophthalmological evaluation at 12 months of age were excluded. The LEA GRATINGS test, developed by Lea Hyv€arinen,4,5 measures detection grating acuity using four paddles, three with gratings on both sides and one with gray surface (Figure 1). The frequency of gratings is defined as cycles per centimeter (cpcm) on the surface of the paddles. Assessment was performed in a room with a luminance of 120-360 lux. Infants were held on their mothers’ laps at a distance of 28 cm from the test. The paddles were organized on a table with low spatial frequencies (wide stripes) on top.4 The gray surface and the grating were presented to the subject and were kept motionless. The response was based on observing the shift of fixation to the grating during binocular measurements. If an infant’s condition prevented measurement, the evaluation was rescheduled. All
563
564
Martini et al
Volume 18 Number 6 / December 2014 three different ages, analysis of variance (ANOVA)9 was used for repeated measures. The profile test by contrasts9 was used to locate differences at different ages.
Results
FIG 1. LEA GRATINGS.
FIG 2. Positive response of the infant.
examinations were performed by one evaluator. The grating detection thresholds were defined as the spatial frequency of the finest grating that resulted in two positive responses (Figure 2). Each subject was evaluated three times, at the end of the first, second, and third month of age. At 12 months of age, children were examined by an ophthalmologist, who performed a clinical evaluation comprising red reflex testing, Hirschberg test, cover test, assessment of ocular motor functions, retinoscopy, biomicroscopy, objective refraction, and dilated fundus examination. Infants diagnosed with ophthalmological abnormalities were excluded. Data related to the infants’ birth conditions were obtained from the newborn’s health card and the data recorded on the evaluation protocols were transcribed and stored in the database of SPSS 16.0 (SPSS Inc, Chicago, IL).6 The data were represented in a frequency distribution as cycles per degree (cpd) and logMAR values. The technique presented in the manual of Teller Acuity Cards7 and in the study by Salom~ao and Ventura 8 were used to determine the means and standard deviations of the cpd values. The data in cpd were converted into a oneoctave scale for statistical analysis and data organization, that is, the cpd values were subjected to logarithmic transformation. Acuity values was reconverted into cpd values for presentation of results. Standard deviations are presented in octaves. For comparison of grating acuity values at the
The first examination, at the end of month 1, included 386 infants; the second, at the end of month 2, 253 infants; and the third, at the end of month 3, 178 infants. Of the 178, 11 were excluded for exceeding the age of 3 months. Thus 167 infants completed the longitudinal follow-up during the first 3 months of life. At the age of 12 months, only 145 children were available for the ophthalmologic evaluation. Of these, 8 were excluded because of incomplete examination, 1 for retinoblastoma, and 3 for constant strabismus, leaving a total of 133 infants (65 males [49%]). Considering an 8% margin of error the number of cases (N) for the present study was 133 infants. The mean gestational age was 39.33 1.12 weeks (range, 37 weeks to 41 weeks and 6 days). The mean birth weight was 3515 387.4 g (range, 2215–4065 g). The Apgar index was $7 in 95.5% of cases during the first minute and 100% during the fifth minute. The racial distribution of infants was as follows: 71 (53.4%), white; 35 (26.3%), black; and 6 (4.5%), other. The records of 21 infants (15.8%) did not provide demographic data. In the first month, the mean age at the time of testing was 39.3 4.0 days (range, 19-45 days); in the second month, 71.6 3.8 days (range, 57-75 days); and in the third month, 102.3 3.6 days (range, 90-105 days). Measurements were taken within 15 days of the exact age of 1, 2, or 3 months. According to the data shown in Tables 1 and 2, binocular responses to gratings showed development toward higher mean values and spatial frequencies. At the age of 1 month, the mean grating acuity was 0.55 0.70 cpd (1.74 0.21 logMAR); at 2 months, 1.35 0.69 cpd (1.35 0.21 logMAR), and at 3 months, 3.11 0.54 (0.98 0.16 logMAR). ANOVA performed on the repeated measurements (at the ages of 1, 2, and 3 months) demonstrated the influence of age on the values (P\ 0.0001); the profile test9 showed significant differences between values at each age. A curve depicting the development of the mean of detection grating acuity was constructed based on the mean values and respective standard deviations obtained for each age group (Figure 3).
Discussion The present study represents the first attempt to determine prospectively a curve of normal development of detection grating acuity from a large cohort of normal infants evaluated longitudinally in the first 3 months of life by the LEA GRATINGS test. The improvement of infants’ ability to detect gratings observed in the present study is similar to findings in other studies using
Journal of AAPOS
Volume 18 Number 6 / December 2014
Martini et al
565
Table 1. Detection grating acuity values (cpd and logMAR) during the first 3 months of life (N 5 133) 0.25, cpd 2.08, logMAR
0.50, cpd 1.78, logMAR
1.00, cpd 1.48, logMAR
2.00, cpd 1.18, logMAR
4.00, cpd 0.88, logMAR
Frequency
f
%
f
%
f
%
f
%
f
%
Month 1 Month 2 Month 3
23
17.3
70 6
52.6 4.5
38 74 4
28.5 55.6 3.0
2 43 40
1.5 32.3 30.1
10 89
7.5 66.9
Cpd, cycles per degree; logMAR, logarithm of the minimum angle of resolution.
Table 2. Mean values of detection grating acuity (N 5 133) Evaluation Month 1 Month 2 Month 3
Mean, cpd
Mean 1.96 SD, cpd
Mean, logMAR
Mean 1.96 SD, logMAR
0.55 1.35 3.11
0.21; 1.44 0.51; 3.52 1.50; 6.56
1.74 1.35 0.98
1.32; 2.16 0.93; 1.77 0.66; 1.30
Cpd, cycles per degree; logMAR, logarithm of the minimum angle of resolution.
FIG 3. Improvement in the detection grating acuity values during the first 3 months of life in CPD and logMAR.
psychophysical or electrophysiological evaluation methodologies during the first 6-12 months of life.2,10 To our knowledge, only 2 previous studies5,11 used the LEA GRATINGS test; however, although LEA gratings have a strong correlation both with Teller Acuity Cards5 and Cardiff acuity cards,11 the results of these studies were not compared with those of the current study because of differences in methodology and age groups. Nevertheless, the results for the three age groups in the current study are similar to those of studies that used the forced-choice preferential looking technique 1 month of age.12,13 Other studies that measured infant visual acuity from birth to 28 days of life also found similar mean values.1416 Values measured during the second month of life17 are close to the corresponding values of the current study;
Journal of AAPOS
binocular values measured at the age of 3 months18 were slightly lower than ours. In their study of normal values for the Teller Acuity Cards, Salom~ao and Ventura8 reported mean acuity was 0.66 cpd at 15 days of age, 2.02 cpd at 2 months, and 3.89 cpd at 3 months—similar to values obtained in the present study. All values of the present study are within the normal values presented in the utilization manual of the test of Teller Acuity Cards (TAC- II; Stereo Optical Co Inc, Chicago, IL).7,8,14 In newborns, measured grating acuity values are strongly affected by the infant’s state of wakefulness. The challenge with this population is obtaining monocular measurements, given that occlusion can further affect infant cooperation. A large improvement in the value might mean that during the previous measurement the infant was not as awake as during the follow-up visit. On the other hand, if the follow-up measurement results in the same or a lower value than the previous measurement, it is wise to repeat the measurement the same day or within a week to confirm that the values are improving normally. Although the binocular values of a single measurement are relevant in infant assessment in the first months of life, it is more important to verify that the values obtained in follow-up tend to grow and remain within the normal range. The American Academy of Pediatrics, the American Association for Pediatric Ophthalmology and Strabismus, and the American Academy of Ophthalmology recommend that visual functions and functioning should be assessed early.19,20 Detection grating acuity is an easy and quick measurement to monitor development of visual functions. Repeated observations on how infants reach the developmental milestones in visual communication and interaction and use vision in motor development are important clinical observations on the development of brain functions. Although the lack of monocular values is a limitation of this study, the binocular measurements provided valuable data on the visual development of infants. Used in conjunction with standard clinical examination techniques, the LEA GRATINGS test provides an easy way to monitor development of visual function in infants.
Literature Search PubMed was searched on November 20, 2012, without date or language restrictions, using the following terms:
566
Martini et al
Volume 18 Number 6 / December 2014
visual acuity, eye health, vision tests, infant care, vision disorders–prevention AND control.
Acknowledgments The authors thank the medical residents and staff of the Ambulatory Service of Ophthalmology of the University of Campinas Clinical Hospital for their collaboration in the evaluation of infants. Special thanks to Dr. Lea Hyv€arinen for her contribution to the realization of this work. We acknowledge the support of the professional staff of the DAANE program (Neonatal Detection of Audiological Alterations) and the important role of the faculty and staff of the Center for Studies and Research on Rehabilitation “Prof. Dr. Gabriel Porto” (CEPRE) of the University of Campinas. References 1. Kaas JH, Jain N. Neural plasticity. In: Wong-Rilley, ed. Neuroscience Secrets. Philadelphia: Hanley and Belfus Inc; 2000:373-83. 2. Costa MF, Oliveira AGF, Bergamasco NHP, Ventura DF. Medidas psicofısicas e eletrofisiol ogicas da func¸~ao visual do recem nascido: uma revis~ao. Psicol USP 2006;17:15-33. 3. Hyv€arinen L, Jacob N. What and how does this child see? Helsinki (Finland): Vistest Ltd 2011;33-8. 4. http://www.lea-test.fi/index.html?start5en/vistests/instruct/leagrati/ leagrati.html. Accessed December 8, 2007. 5. Yudcovitch L, Linden ME, Maeda J, Shore N. An evaluation of infant visual acuity using Lea Grating Paddles e Teller Acuity Cards. J Optom Vis Dev 2004;35:224-9. 6. Statistical Package for Social Sciences for Personal Computer for Windows. Base System User’s Guide, Release 6.0. United States of America: SPSS Inc.; 2003:365. 7. Teller DY, Dobson V, Mayer L. Teller Acuity Cards—II Handbook. Vistech Consultants Inc, Dayton Ohio 2005. 8. Salom~ao SR, Ventura DF. Large-sample population age norms for visual acuities obtained with Vistech-Teller acuity cards. Invest Ophthalmol Vis Sci 1995;36:657-70. 9. Montgomery DC. Design and Analysis of Experiments. 3rd ed. New York: John Wiley & Sons; 1991.
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An Eye on the Arts—the Arts on the Eye
We don’t close our eyes to the Universe and then complain: “It’s dark”. We keep our eyes wide open, knowing that the light could lead us to do undreamed of things. That is all part of love. —Paulo Coelho, Manuscript Found in Accra (New York: Alfred A. Knopf, 2013), 78. Contributed by Alex V. Levin, MD, MHSc, Philadelphia, Pennsylvania
Journal of AAPOS