Ophthalmology

Introduction

Visual function and self-perceived visual impairment are important aspects of health-related quality of life. The National Eye Institute 25-item Visual Function Questionnaire (NEI-VFQ-25) has been demonstrated to be reliable and valid as a measure of vision-specific health-related quality of life.¹ This questionnaire is used to assess self-perceived visual impairment in a variety of ocular disorders. However, little information is available in the literature regarding vision-related quality of life for individuals with congenital ocular abnormalities. In this study, we used the NEI-VFQ-25 to assess vision-related quality of life for adolescents and young adults who underwent surgery for bilateral or unilateral congenital cataract in the first 2 years of life.

Patients and Methods

Approval for this study was granted by the Institutional Review Board of The Children’s University Hospital, Temple Street, Dublin. A chart review was conducted for all children who underwent cataract surgery between 1984 and 1996. Children with congenital cataracts removed before 24 months of age who were 13 years or older at the time of the study were selected for inclusion. Data collected included age, laterality of cataract, and best-corrected visual acuity (BCVA) at latest review. Those with Down syndrome or a history of persistent fetal vasculature were excluded from the study. The self-administered form of the VFQ-25 was either posted to suitable patients or was completed during attendance at the clinic. Information regarding the current level of education or employment was also obtained. A group of similarly aged individuals was also selected to form a control group. This group comprised visitors to the hospital with no visual or medical problems who were willing to undergo visual acuity assessment and to complete the questionnaire.

The 25-item VFQ contains 26 items, 1 of which relates to general health and 25 of which are vision targeted. These items are grouped into 12 subscales (Table 1). Using the VFQ-25 scoring algorithm, the subscales were scored on a scale from 0 to 100, with 100 indicating the highest level of functioning. The composite score was calculated as the unweighted mean of the vision-targeted subscales, thus excluding the general health subscale. The composite score and the mean score for each subscale was calculated for the unilateral and bilateral cataracts groups and for the control group.

Table 1: Subscales of the National Eye Institute 25-Item Visual Function Questionnaire

The scores recorded by each cataract group were compared using a two-tailed t test for independent groups. Each group was also compared separately with the control group. A P value of .05 or less was deemed to be statistically significant. Correlation between BCVA and subscale scores in the cataract groups was determined using the Pearson product moment correlation coefficient “r.”

Results

Thirty-eight patients with a history of congenital cataract surgery (22 female, 16 male) fulfilled the inclusion criteria and agreed to take part in the study. Sixteen (11 female, 5 male) had a history of unilateral and 22 (11 female, 11 male) of bilateral cataract. The mean age of both cataract groups at the time of cataract surgery and conduction of the study were not significantly different (P = .47 and P = .17, respectively; Table 2). In the unilateral group, BCVA in the affected eye was better than 6/60 Snellen in 25% and 6/60 or worse in 75% of patients (Fig. 1), but binocular BCVA was 6/9 or better in all cases (Fig. 2). In the bilateral group, 31.8% had a binocular BCVA of 6/12 Snellen or better and the remainder were between 6/18 and 6/60 (Fig. 3).

Table 2: Demographics, Educational/Occupational Attainments of Patients With History of Unilateral and Bilateral Congenital Cataracts

Figure 1. Best-corrected visual acuity (BCVA) Snellen in affected eye of patients with history of unilateral congenital cataract. CF = counting fingers; HM = hand motions.

Figure 2. Binocular best-corrected visual acuity (BCVA) Snellen in patients with history of unilateral congenital cataract.

Figure 3. Binocular best-corrected visual acuity (BCVA) Snellen in patients with history of bilateral congenital cataract.

At the completion of the current study, 9 patients in the bilateral group and 7 in the unilateral group were attending full-time, main stream school. Ten patients in the bilateral group and 6 in the unilateral group were attending university. Three patients in each group had full-time employment (Table 2).

Fifteen individuals (9 male, 6 female) with a mean age of 17.9 ± 2.5 years participated in the control group. All had a BCVA in each eye of 6/9 Snellen or better.

NEI-VFQ-25

There was no significant difference in the general health subscale score of each cataract group (Table 3). In addition, no difference was found between these groups in terms of general vision, ocular pain, vision-specific dependency, color, and peripheral vision subscale scores (Table 3). Three (13.6%) of the 22 patients in the control group and 4 (25%) in the unilateral group held driving licenses at the time of the study and completed the section on driving. This subscale was therefore not analyzed. Of note, not all study participants were of legal driving age and more participants fulfilled the visual criteria for driving.

Table 3: Subscale Scores in Patients With History of Unilateral and Bilateral Congenital Cataract Using the NEI-VFQ-25

Statistically significant lower subscale scores were recorded in the bilateral group compared with the unilateral group in the following categories: ability to perform both near and distance activities, vision-specific social functioning, vision-specific role difficulties, and vision-specific mental health.

In the bilateral group, a moderately strong correlation was found between visual acuity in the better seeing eye and the vision-related mental health subscale score (r = 0.63). No correlation was found between other subscale scores and visual acuity in the better or worse seeing eye in the bilateral group or the affected eye of the unilateral group (Table 4).

Table 4: Correlation Between Subscale Scores and Visual Acuity in Better and Worse Seeing Eyes in the Bilateral Group and Visual Acuity in the Affected Eye of the Unilateral Group

Control group participants scored better in the general health subscale (95 ± 10.4) than either the unilateral (P = .03) or bilateral (P < .001) group. In all other subscales, the control group scored maximum points. Compared with the unilateral cataract group, the controls did statistically significantly better in the following categories: general vision (P < .01), near activities (P = .001), distance activities (P = .003), peripheral vision (P < .001), vision-related mental health (P < .001), and composite score (P = .006). The control group scored better than the bilateral group in all categories except color vision (P = .16).

Discussion

The effect of various ocular disorders on vision-related quality of life is of increasing interest. The findings are useful for the planning and provision of appropriate services and in assessing the impact of intervention and treatment of ophthalmic disorders. Various questionnaires are available, some of which assess overall health-related quality of life and some of which target more specifically vision-related quality of life. For the ophthalmologist, more information can be obtained from the latter, but both are frequently used. The SF-36 is a generic questionnaire used to assess health-related quality of life. Chia et al. used this to examine the impact of unilateral visual impairment in older individuals on health-related quality of life and found that moderate to severe uncorrectable unilateral visual impairment impacted significantly on health-related quality of life.² The NEI-VFQ-25 is commonly used for assessing vision-related quality of life. Varma et al.³ examined the effect of laterality and severity of visual impairment on vision-related quality of life in patients older than 40 years using the NEI-VFQ-25. It was found that patients with mild bilateral and unilateral/bilateral moderate and severe visual impairment had greater difficulty when performing most vision-dependent activities of daily living, had poorer vision-related mental health, and had vision-related dependency.³ The NEI-VFQ-25 has also been used to assess vision-related quality of life in patients with visual field loss,^4,5 diabetes mel-litus,^1,6–9 age-related macular degeneration,^1,10 age-related cataract,¹ and visual dysfunction related to multiple sclerosis.¹¹ It is also useful in assessing the impact of medical and surgical intervention.^9,12

Children with congenital cataracts continue to present a significant challenge to the pediatric ophthalmologist. The timing of surgery and question of primary intraocular lens implantation are among some of the important management decisions required. Postoperative complications, such as the development of glaucoma, may significantly alter visual prognosis. Visual rehabilitation with glasses or contact lenses and aggressive amblyopia management are of the utmost importance to optimize visual potential.

Ye et al. examined the influence of bilateral congenital cataract on vision-related quality of life in children. Thirty-six children with a mean age of 9.8 years were examined before and after cataract extraction.¹³ Quality of life was found to be severely impaired in those children with bilateral cataract and was influenced by density of opacity, visual acuity, and cataract extraction.

Chak et al. examined the impact of congenital/infantile cataract on children (mean age: 6.8 years) and their parents using the PedsQL 4.0, a multidimensional pediatric health-related quality of life questionnaire.¹⁴ Thirty-three parent–child pairs completed the questionnaire and the overall scores were found to be comparable to those of children with severe systemic diseases and some cancers. However, the PedsQL 4.0 examines health-related quality of life and does not specifically relate to vision-related quality of life. Wong et al. also used the PedsQL 4.0 questionnaire to determine the effect of visual impairment on health-related quality of life.¹⁵ A total of 1,249 adolescents with a mean age of 13.8 years from the Singapore Cohort Study of the Risk Factors for Myopia were involved in the study. A statistically but not clinically significant association was found between visual impairment and impaired total, psychosocial, and school functioning quality of life scores.

This is the first study to report the long-term impact of visual impairment secondary to congenital cataracts removed at a young age on vision-related quality of life in adolescents and young adults. The NEI-VFQ-25 proved easy to use. Although the question relating to driving was not appropriate for all patients, this did not pose a problem or interfere with the study outcome because the questionnaire design allowed for the fact that many adult patients partaking in such a study may have no desire to drive, which is unrelated to visual ability. We found a high degree of educational attainment in our patients. Irrespective of laterality of cataract, all participants questioned were currently in or had completed main stream school. Twelve of the 22 patients in the bilateral group and 7 of the 16 patients in the unilateral group were in the process of attaining or had already attained university qualifications. Two further patients in the unilateral group had completed apprenticeships and had skilled employment.

On examination of the NEI-VFQ-25 scores, the unilateral cataract group performed significantly better in relation to both near and distance activities than the bilateral group. The bilateral group reported significantly greater difficulty with vision-specific social functioning and role difficulties than the unilateral group. This is not surprising given the excellent binocular visual acuity in the unilateral group. The bilateral group also scored worse in terms of vision-specific mental health scores, which is understandable given the bilateral nature of their condition. Interestingly, a moderately strong correlation was found between BCVA in the better-seeing eye of this group and the vision-specific mental health subscale score, highlighting the link between the two parameters. There was no statistical difference between both groups in relation to general vision, vision-specific dependency, and peripheral vision.

Interesting results were obtained when comparing the scores obtained by the unilateral cataract and control groups. Although patients in the former group had excellent binocular visual acuity, they attained significantly lower scores than controls in several categories. Importantly, they had more difficulty with both near and distance activities and with peripheral vision. However, there was no significant difference in terms of vision-specific social functioning, vision-specific role difficulties, and vision-specific dependency, indicating that these young individuals have a high level of visual function as we would expect. However, they did have lower vision-related mental health scores, most likely relating to fear of losing vision in their better eye.

The adolescents and young adults in this study achieved a high level of visual function with excellent educational achievements irrespective of laterality of cataract. The NEI-VFQ-25 proved easy to use and was applicable for this age group. The unilateral group scored better than the bilateral group in many subscales, but both groups were comparable in terms of general vision subscale scores. These findings are encouraging for both patients and those involved in their care, particularly because they reflect outcomes of individuals on whom surgery was performed many years ago. Over time, surgical techniques have improved, as has the management of refractive error and amblyopia. In the future, it will be interesting to assess whether these advances are reflected in patients’ vision-related quality of life.