Relationship between the Children’s Visual Function Questionnaire and psychophysical measures of visual acuity and chromaticity discrimination in older visually impaired children

Abstract

The Children’s Visual Function Questionnaire (CVFQ) is an instrument to measure the impact of visual impairment in children and their families. It can be used as a research tool to verify the effectiveness of treatment, therapy, and different methods for visual stimulation and rehabilitation. The aim of this study is to describe the relationship between General Health, General Vision Health, Personality, Family Impact, and Treatment – subscales of the CVFQ and psychophysical measures of visual acuity (VA) and chromaticity discrimination (CV). This prospective, cross-sectional study was conducted at the Sensory Psychophysiology Laboratory – University of São Paulo in partnership with the Ambulatory of Visual Stimulation in the Sector of Low Vision and Visual Rehabilitation – Federal University of São Paulo. The children who participated in this study were divided into two groups: study group (SG), composed of 11 children with a diagnosis of visual impairment and mean age of 55.36 months (SD = 16.88), and control group (CG), composed of 8 children with normal vision and mean age of 64.87 months (SD = 13.22). Both groups underwent the application of CVFQ, were tested for VA using the Teller Acuity Cards (TAC) test, and CV using the Cambridge Colour Test program for children (CCT Kids). The result of applying the CVFQ to groups of children over 3 years, comparing SG and CG, differences were observed in the following subscales: General Vision Health (F = 10.00, p < .001); Competence (F = 7.03, p = .030); Personality (F = 6.48, p = .010); Total Quality of Life (F = 11.39, p = .010). These differences show a worse score for the SG. In the VA test using TAC, the data collected in groups of children over 3 years, comparing SG and CG, differences were observed in VA RE (F = 19.25, p < .001); VA LE (F = 25.99, p < .001); VA BE (F = 15.45, p < .001). These differences show worse scores for the SG. In the CV using the CCT Kids, the data collected in groups of children over 3 years, comparing SG and CG, no statistically significant differences for protan, tritan, and deutan groups were observed. For the SG, while for children over 3 years, correlations were found for General Vision Health, Competence, Family Impact, and General Quality of Life. We conclude that there are statistically significant differences when comparing the SG with the CG for the visual function of visual acuity and chromaticity discrimination, and we also demonstrated the sensitivity in the use of CVFQ in reflect VA and CV impairments.

Keywords

Children’s low vision Children’s Visual Function Questionnaire quality of life vision quality of life visual impairment children visual rehabilitation

Introduction

Children with visual impairment show difficulties in their development, which affect their family and society (Boulton et al., 2006; Santana et al., 2005; Tartarella et al., 1995; Wolffsohn & Cochrane, 2000). Visual compromise may cause difficulties in basic everyday skills such as feeding oneself or looking for an object (Stelmack, 2001). Visual impairment, therefore, influences the general health, development, and child’s wellbeing (Chak et al., 2007).

A newborn has developed organs from the anatomic point of view. However, the functional connections needed for the performance of a variety of activities are not yet developed. Therefore, not having the adequate visual functionalities during the development entails compromising activities such as motor and cognitive learning, and without the visual input it is necessary a different investigation and follow-up for full development and quality of life (Barraga, 1986; Cruz et al., 2005; Gagliardo, 1997; Glass, 2002; Prechtl et al., 2001; Rodrigues, 2002).

Assessments of the impact of the visual problem in the child’s life, and data of visual functions, are not often or practically never done (Chak et al., 2007), Therefore, the study on children with visual impairment, the relation between the data of quality of life, and the psychophysical measures of visual acuity and chromacity discrimination are rather relevant.

Methodology

This prospective, cross-sectional study was conducted at the Sensorial Psychophysiology Laboratory of the Experimental Psychology Department of the Psychology Institute and linked to the Postgraduate Program in Neuroscience and Behavior of the University of Sao Paulo/USP in partnership with the Ambulatory of Early Visual Stimulation in the Sector of Low Vision and Visual Rehabilitation, linked to the Department of Ophthalmology and Vision Science of the Federal University of Sao Paulo/UNIFESP.

The study followed the principles of the Helsinki Declaration and was forwarded for approval by the Committee of Ethic in Research of the University of Sao Paulo – Document 98.812 issued by same Committee of Ethic.

The children who were invited to participate in this study were allocated in two different groups: study group (SG), composed of children with visual impairment, and control group (CG), composed of children with normal vision for their chronological age.

Criteria for the inclusion in the study group: low vision diagnosis, with optical correction, who had or not undergone treatment (surgery, glasses, occlusion patch); minimum acuity of 20/20; with age between 3 and 7 years; both genders; and absence of neurological changes and/or other associated systemic diseases. For the children of the control group, the defined criteria were as follows: diagnosis of normal vision and/or without correction for the chronological age, both genders, absence of neurological changes, and/or other associated systemic diseases.

The study group was composed of 11 children, with age between 3 and 7 years, mean age of 55.36 months (SD = 16.88), and they were six females and five males. The causes of visual impairment varied from compromise by visual deprivation: congenital cataracts (n = 03) and opacity of cornea, to retinal compromise: albinism (n = 02), retinal coloboma (n = 02), and congenital glaucoma (n = 04). Meanwhile, the control group was composed of eight children, with age between 4 and 7 years, mean age of 64.87 months (SD = 13.22), and they were two females and six males.

It is important to emphasize that the children in the study group, who are visually impaired children, kept their follow-up at the same clinic after participating in this study.

The procedure initially consisted of applying the Children’s Visual Function Questionnaire 3–7 (CVFQ 3–7), in individual interviews with parents/caretakers/legal guardians accompanied by the child. After the measurement evaluations of visual acuity (VA) through the tests of Teller Acuity Cards (TAC) and chromatic sensibility, color vision (CV), using the Cambridge Colour Test (CCT Kids) program for kids. The mean time for the tests was approximately 40 min each, with an interval of 10 min between tests. The order of the tests was random, and the duration depended directly on the collaboration of each child.

Describing the instruments used in this study, the available QFV has two different presentations: one for children under 3 years old (QFVI-3) and the other for children over 3 years old (3–7 years old) – (QFVI-7). The Teller Acuity Card test consists of 17 cards, each with a spatial frequency grid from 0.32 cycles/cm to 38 cycles/cm (Teller, 1989). Visual acuity measurement followed the procedure described in Teller’s Acuity cards manual, modified by Salomão and Ventura (1995). CCT Kids is validated by the study by Goulart et al. (2008). The modified version of the CCT Kids, Cambridge Research Systems Ltd., Rochester, UK, was an adaptation of the Trivector mode of the Mollon-Reffin color discrimination test, developed at the Sensory Psychophysiology Laboratory – Postgraduate Program in Neurosciences and Behavior at the University of São Paulo.

The statistical analysis was done with the Statistica program (StatSoft Inc, Tulsa, Ok, USA, version 12). The statistical differences were tested with analysis of variance (ANOVA) of Repeated Measurements and post hoc tests, such as Mann–Whitney U Test, for univariate analysis highlighting the distinct groups. Pearson Correlations, Spearman Rank Order Correlations, and Frequency Measurements looked for association effects between age and questionnaire scores, with the values of AV and color vision.

Results

The result of the application of the CVFQ for the groups of children over 3 years was compared between the study and control groups, and differences were observed between the following subscales: Vision General Health (F = 10.00 and p < .001), Competence (F = 7.03 and p = .030), Personality (F = 6.48 and p = .010), and Total quality of life (F = 11.39 and p = .010). These differences show a worse score for the study group (Graph 1).

Graph 1.

Representation of mean values and standard deviation found in the application of the CVFQ for children in the control and study group over 3 years.

In the visual acuity test, using the Teller Acuity Cards, the collected data in the groups of children over 3 years were compared between the study and control groups, and differences were observed between visual acuity of right eye (VA RE) (F = 19.25, p < .001), visual acuity of left eye (VA LE) (F = 25.99, p < .001), and visual acuity of both eyes (VA BE) (F = 15.45, p < .001). These differences show a worse score for the study group (Graph 2).

Graph 2.

Representation of the mean values and standard deviation found in the application of the visual acuity test using TAC for children from the control and study group over 3 years.

In the color vision test, using the CCT Kids, the collected data in the groups of children over 3 years were compared between the study and control groups, and statistically significant differences were not observed for the groups Protan, Tritan, and/or Deutan to the right eyes (RE), left eyes (LE), and both eyes (BE) (Graph 3).

Graph 3.

Representation of mean values and standard deviation found in the application of color vision test using CCT Kids to children from the control and study group over 3 years.

For the study group, children over 3 years, the correlation between visual functions and the CVFQ is present between the following variables (p = .05) – values of R², those in bold being statistically significant (Table 1).

Table 1.

Correlation between the visual functions and the subscales of the CVFQ for children over 3 years in the SG.

	VA RE	VA LE	VA BE	PROT RE	DEUT RE	TRIT RE	PROT LE	DEUT LE	TRIT LE	PROT BE	DEUT BE	TRIT BE
General Health	0.03	0.31	−0.34	0.03	−0.13	−0.13	0.20	−0.23	−0.24	0.10	−0.41	0.46
General Vision Health	−0.18	−0.04	−0.67	0.32	−0.36	−0.44	0.01	−0.41	−0.09	−0.02	−0.05	−0.34
Competence	−0.60	−0.33	−0.70	−0.30	−0.94	−0.76	−0.61	−0.88	−0.68	−0.41	−0.79	−0.42
Personality	−0.34	−0.55	−0.47	−0.35	−0.54	−0.38	−0.60	−0.38	−0.36	−0.46	−0.55	−0.39
Family Impact	−0.76	−0.60	−0.79	−0.13	−0.73	−0.70	−0.40	−0.61	−0.43	−0.49	−0.44	−0.95
Total Quality Of Life	−0.74	−0.42	−0.77	−0.44	−0.93	−0.86	−0.52	−0.78	−0.70	−0.40	−0.88	−0.47

CVFQ: Children’s Visual Function Questionnaire; SG: study group; VA: visual acuity; RE: right eye; LE: left eye; BE: both eyes.

Regarding the children over 3 years from the study group, the correlation between the subscales of the CFVQ and the age, a correlation was found in the family impact (R² = 0.64 and p < .05) and total quality of life (R² = 0.65 and p < .05). As to the visual functions, the correlation was observed in visual acuity of right eye (R² = −0.76 and p < .05), protan both eyes (R² = −0.80 and p < .05), deutan both eyes (R² = −0.71 and p < .05), and tritan both eyes (R² = −0.77 and p < .05).

As to the study group, allocated according to its visual affection compromise – retinal and optic nerve compromise, visual deprivation, and the group of children over 3 years, the comparisons were found in the following variables: Competence (F = 121.44 and p < .01), being the highest value for the children with retinal and optic nerve compromise; Personality (F = 33.86 and p = .004), with higher value found to retinal and optic nerve compromise; General quality of life (F = 20.21 and p = .011), with higher value to retinal and optic nerve compromise; Protan of right eye (F = 11.52 and p = .027), with higher value to visual deprivation; Deutan of right eye (F = 26.82 and p = .007), with higher value also in visual deprivation. Therefore, compromise is higher to the group of children with visual deprivation over 3 years.

The competence subscale was the only one to show difference between the number of children and/or siblings from the same family and the same household and the subscales of the CVFQ with statistical significance (Z = 2.24 and p = .03).

Discussion

The interest in the concept of quality of life is relatively recent and it comes from actions and attitudes associated with the rehabilitation sectors. The conditioning and determining factors of the health and disease process are multifactorial and rather complex (Seidl & Zannon, 2004). Vision problems, ocular diseases, and visual impairment may cause an impact in the quality of life of children and their family, causing damage to the skills and acquisition of the global neuropsicomotor development. (Birch et al., 2007; Chadha & Subramanian, 2011; Lopes et al., 2009; Messa et al., 2012).

As verified in previous studies, Lopes et al. (2009), the Children’s Visual Function Questionnaire (CVFQ) is sensitive to visual acuity function, but only when it comes to children with congenital cataracts. The compromise of quality of life related to vision in children with retinopathy of prematurity was also appointed by the same questionnaire in Messa’s (2013) study. In the present study, the sensibility of the questionnaire in relation to children with visual impairment of different etiologies is described, and acuity visual functions and color vision losses in quality of life were also observed.

With the study of the variables which influence the quality of life of children with visual impairment over 3 years, the subscales significantly compromised with low scores in quality of life were general vision health, competence, personality, and life, which is in relation to the control group from the same age.

Messa et al. (2012) using the same instrument which we used in our study observed improvement in the quality of life after the intervention of therapists in low vision. According to the statistical analysis of data, the comparison between the subscales showed significant difference in general vision health, competence, and general quality of life for the group of children under 3 years. In the group of children over 3 years, the comparison between the subscales was significant for the subscales of general health, general vision health, personality, and general quality of life. In the findings of this study, children showed differences in the same subscales including personality and family impact, as to older children the identified differences were in general vision health, competence, personality, and general quality of life.

Souza et al. (2010) also observed in their study that children with visual impairment show global delay in the neuropsicomotor development and in the functional vision in comparison with children without this kind of impairment, and regarding the behaviors addressed in the assessment – motor, coordination, language, and social – the coordination behavior was noticed to be the most compromised one.

As to the group of children over 3 years with visual impairment, compared to the control group, a difference between monocular visual acuity and also of both eyes was observed in the visual acuity test, therefore showing a worse score for the group with statistically significant visual impairment. In this group, children over 3 years, a difference was also observed in the values found for the color vision test; this visual function was not sensitive to the application of the CVFQ.

So, the comparison between groups, study and control, was sensitive to the acuity function, but not to the color vision, and this is in relation to the application of the CVFQ and the values of the subscales. This behavior of the values may be a pattern of the instrument, once it may be focused on the other visual functions, besides color vision.

Actually, this is a reflection of the conventional clinical approach, since it is based on a validation of the instruments system, which takes the most used clinical measurement as a parameter. Being then visual acuity, which the ophthalmologist already measures at the clinic, often adopted as a classic measurement and it is far the most studied visual function. The CVFQ, and other developed instruments, may use visual acuity as the most important visual function, or even the only one, to draw functional activities (Bicas, 2002; Boothe et al., 1985; Santos & Simas, 2001).

However, this function, visual acuity, describes the performance of the visual system for details in fixed, usually high, levels of contrast. Even in the spatial subscale, this function is less descriptive than, for instance, sensibility to luminance contrast (Bicas, 2002; Boothe et al., 1985; Santos & Simas, 2001).

When it comes to functionality, which is the main concern of rehabilitation and habilitation, this function brings little information. Authors such as Felippe and Felippe (1997) and Ames (1992) highlight that rehabilitation and functionality are continuous processes, which extend to experiences beyond the limits of the medical care, such as clinics and ambulatories; therefore, environments are not always adapted and faraway from the maximum contrast.

According to the Planning Basic Rehabilitation Countries apud Helander (2002) and with the resolutions of the World Blind Union, services for people with visual impairment should involve the following areas: Social Service (seeks the needs of the person, family, and team); Psychology (aims at obtaining favorable internal conditions to the process); Physiotherapy (movement therapy, development therapy, aims at the full capability of the person); Everyday Tasks (develops a program which seeks the execution of the day-by-day care in an independent and self-sufficient way); Communication (readaptation of the written communication and in the informative process, but also in the educational, vocational, and professional career aspects); Orientation and Mobility (seeks the physical locomotion and mental orientation, aiming at independence in locomotion); Professional Orientation (assessment and follow-up of the person’s potentialities and needs, and the demands of the job market). Therefore, it is a broader view of functions such as depth, colors, and movement, inter alia.

As for the correlation between the variables, from the group of children over 3 years, it was observed between the subscales of general vision health, competence, family impact and general quality of life, and visual functions, not only acuity but also color vision. However, the correlation with color vision took place only between deutan and tritan. The negative correlation of these variables showed that the smaller the acuity values and color vision, the smaller the thresholds and they describe higher sensibility of these functions, thus the higher will be the values found in the subscales, and consequently the better the quality of life of this group;

The color vision in the protan axis was the only function which did not show correlation between the subscales of the variables, probably due to the big variability, for it is a group with people with impairment. Moreover, it is observed in the clinical practice – Ambulatory of visual stimulation of the Federal University of São Paulo, the preference of children with visual impairment for red and orangish stimuli. Our result shows the protan axis of confusion relatively preserved in this group of children, and this may support this clinical trial.

Rossi (2010) also did not show significant differences in the color vision in the application of her Functional Vision Assessment in Children instrument – 2 to 6 years children with low vision. And, although the color vision is rather studied in its psychophysical aspects (Bruni & Cruz, 2006; Ventura, 2007), there are scarce data in the literature about color perception in age groups, mainly in the children group.

Regarding the correlation between the subscales of the CVFQ, the visual functions and the age of the children in this study, it was observed that the study group of those over 3 years showed an improvement in its performance as they grew up. Meanwhile, the subscales of family impact and general quality of life show that the more the child grows, the better the subscale is and therefore, the higher the values of quality of life. However, it is not clear to say that children with visual impairment have the same functional dimension of adults with impairment.

The CVFQ showed itself to be more sensitive to the group of children over 3 years. This may be due to the difficulty for parents/caretakers/legal guardians to realize in the first years of life, the immaturity or delay in the neuropsicomotor and visual development of small babies. It may also be that parents/caretakers/legal guardian of older children are more informative, showing more experience and interaction with their own child, better knowing their behavior and performance. Or even, both situations, in relative levels. In a way, the impact of visual impairment observed by parents/caretakers/legal guardian is bigger in more complex tasks, which older children are able to perform and younger ones cannot.

A similar study was conducted by Droste et al. (1991). These authors studied 14 children, from 5 to 17 years, with retinopathy of prematurity and 31 children, from 3 to 44 months, with other ophthalmologic diagnosis of low vision. The correlation between visual assessment battery (group of indicators of behavior) and the results of resolution acuity was the same for children with development problems and children with normal development. However, the correlation between the resolution acuity and the visual assessment battery was better for children over 1 year than to younger ones.

The data from this study showed that the older the child is, the higher the quality of life values, especially in relation to family impact, competence and total performance in quality of life. While in the color vision function, children with visual impairment revealed that they developed their sensitivity about their growth in age.

When compared to the children from the group with visual impairment, subdivided in the groups by their ocular affections, the children with visual deprivation showed the worse quality of life. The values of quality of life were superior for children with retina and optic nerve compromise, while the values for the visual functions were higher for children with visual deprivation, therefore, less sensitive to the stimuli.

At first, it is observed that the deprivation causes more drastic effects on the vision development, mainly during the critical period of visual development. The child’s brain, when it does not receive adequate visual stimuli, results in the deficient development of vision, once there are no necessary stimuli for the development of neuronal pathways. If this deprivation is extended for a long period of time, an irreversible neurological injury may take place, being represented by atrophy of neurons of the lateral geniculate body and the striate cortex (Freeman, 2009; Lewis & Maurer, 2005). Besides that, the visual deprivation interferes in the interaction of children with their family, starting with the “eye-to-eye” contact with their mother, which is, commonly, established between both (Botega & Gagliardo, 1998).

Another study related to the questionnaire and vision is the one described by Gothwal et al. (2003). The LV Prasad-Functional Vision Questionnaire (LVP-FVQ) was elaborated to assess functional difficulties related to vision of children with vision impairment at school age. This one, composed of 19 items, was given orally to 78 students with visual impairment, from 8 to 18 years. It showed to be sensitive in identifying difficulties related to simple tasks such as walking in a corridor and reading a book using arm distance, once they describe a worse performance to see in relation to their peers with normal vision. In our study, children with visual impairment also showed a worse performance in their skills, such as competence in task achievement.

Katsumi et al. (1998) observed the correlation between resolution visual acuity and another questionnaire, the Visual Ability Score (VAS) questionnaire – applicable to parents – in 600 children, from 15 months to 14 years. These authors described a very high correlation between the result of resolution visual acuity and the one from VAS, which indicated that questions from the questionnaire corresponded to the parents’ observations about the visual function of children with low vision. This relation between the findings of visual acuity and scores given by the questionnaire was also found in our research.

In a research performed by the Retina Foundation of Southwest, an institution in which the CVFQ was developed in a partnership with the Federal University of Sao Paulo, data from children with strabismus, refractive errors, congenital cataracts, and retinopathy of prematurity were collected. Children showed low values of quality of life, similar to the data found in this study (Birch et al., 2007).

Other studies used different, but comparable, questionnaires of quality of life and found similar results. The application of the questionnaire PedsQL 4.0 (Pediatric Quality of Life Inventory) for children with congenital cataracts was described in the study of Chak et al. (2007). This questionnaire is composed of related items about physical health (motor tasks) and psychological aspects, such as conditions lived at school, in social life and emotional functions. Because its score is similar to the one adopted by CVFQ, we can propose some comparisons. Regarding the condition of physical health, a value of 81 was obtained, psychological conditions scored 73 out of 76, whereas the values obtained in the CVFQ were 56 to the group under 3 years and 69 to the older ones, this for the condition of general quality of life, whereas for general health, the values were 83 and 86, respectively.

On the same line, Boulton et al. (2006) used other questionnaires and methods of assessment to investigate the quality of life of children with visual impairment, and they found similar results, for the visual loss followed the low quality of life related to vision; however, this study took into consideration the severity of the impairment, while the current one researched about other visual functions and its relation to the sensibility of the instrument – CVFQ.

Few researches describe the concern with the global functional performance in children vision, and with the reduced quantity of studies relating basic visual functions, such as visual acuity and color vision, to questionnaires of quality of life, which are constantly reported in the literature as a “sensitive instrument of measurement of the functional impact of vision in the quality of life,” we reinforce the importance of systematically extending the relation between visual function and the reports about the difficulties in achieving functional skills. (Rossi et al., 2011).

The relation between quality of life and visual impairment cannot be described in an absolute way. In this relation, the measurements go beyond the clinic measurements of vision, when characterizing the importance of the loss of the visual functionality to the quality of life when it comes to perception and adaptation to a situation of life. Therefore, the instrument of CVFQ can bring broader information, which extrapolates possible injured visual functions and also functional behavior.

This instrument, CVFQ, has already shown itself to be efficient at measuring quality of life related to vision in families who use services of visual rehabilitation (Lopes et al., 2009; Messa et al., 2012). But we believe that the CVFQ can be an excellent instrument of assessment of visual functionality and, indirectly, work as an indicator of assessment of the visual functions, and not only of quality of life, literally. Our idea to associate the measurements of visual functionalities obtained indirectly using the CVFQ with the direct measurements obtained in the tests of spatial and chromatic visual functions tries to contemplate the lack of knowledge which separates these two universes. Our data show a relation between these two measured dimensions, which will definitely contribute to fill a relevant gap to visual rehabilitation.

For the groups of children over 3 years, compared between the SG and CG, differences were observed between the following subscales: General Vision Health, Competence, Personality, and Total Quality of Life. In the test of VA using TAC, differences were observed between VA RE, VA LE, and VA BO. For the test of CV using the CCT Kids, the gathered data did not show any differences for the groups Protan, Tritan, nor Deutan.

In the correlation between the visual functions and the CVFQ of the SG, for the children over 3 years: General Vision Health, Competence, Family Impact and Total Quality of Life.

The collected data in the current study show a difference when compared to the SG and CG for the functions of visual acuity and discrimination of chromacity, highlighting the sensibility in the use of the CVFQ in order to detect injuries in the functions of Visual Acuity and Color Vision.

It was possible to conclude that the CVFQ can be a possible sensitive tool to detect impairment of visual acuity and color sensitivity in children. In addition, it can be used as an instrument to assess the functional vision of children with visual impairment.

Another relevant and important data were that it was possible to identify that children aged 3 to 7 years with visual impairment have compromised their quality of life, which is related to their general health status, competence to perform children’s activities, and the impact that the disability has brought to their families.

Footnotes

Appendix 1

Here the gross values of each group are described: study (VI) and control (NT) in Tables 2 to 7.

Declaration of conflicting interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The author(s) received no financial support for the research, authorship, and/or publication of this article.

ORCID iD

Marcia Caires Bestilleiro Lopes

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