Is Patching After Age 4 Beneficial for Children Born with a Unilateral Congenital Cataract?

Abstract

Objective:

The goal of these analyses is to provide evidence that can help parents and health care providers determine whether or not to continue occlusion therapy once a reliable measure of optotype acuity can be obtained in children who are born with a unilateral congenital cataract.

Design:

Data from the Infant Aphakia Treatment Study (IATS) are used in a cohort design.

Participants:

105 children who participated in the IATS and did not have a vision-threatening adverse event.

Methods:

We assessed the relationship between visual acuity at age 10.5 years and average daily hours of patching reported by caregivers on quarterly 48-hour recall interviews and annual 7-day patching diaries obtained between 48 and 60 months of age.

Main Outcomes:

Monocular visual acuity was assessed at the clinic visit closest to 48 months of age using the Amblyopia Treatment Study-HOTV protocol. Final visual acuity was measured at age 10.5 years using the E-ETDRS testing protocol.

Results:

Visual acuity measurements obtained at age 4 were reliable, with a single measure intraclass correlation coefficient of 0.83 (95% CI 0.78,0.88) and were predictive of those obtained at age 10.5 (r_Spearman = 0.83 (p<0.01)). Forty percent (n=48) of the children, the visual acuity measured at age 10.5 years was within ±0.15 logMAR of the measurement obtained at age 4. The amount of patching that was received between the 4^th and 5^th birthdays was unrelated to changes in visual acuity.

Conclusions:

These analyses suggest that optotype acuity measures obtained early in the 5^th year of life are reliable and are predictive of final visual outcomes. Additionally, our results suggest that less aggressive patching protocols, or discontinuing patching altogether, may be justified in some children, particularly those with poor vision, once optotype acuity can be measured. However, the potential impact of latent nystagmus on uniocular visual acuity measurement and the effect of patching on the child’s quality of life, family relationships, and binocular visual field need to be considered before discontinuing occlusion therapy.

Precis:

Visual acuity outcomes of children treated for unilateral congenital cataract can be reliably measured in the 5^th year of life and patching after this point may have little impact on the child’s later visual functioning.

Introduction:

Early cataract extraction, followed by ongoing correction of residual refractive error and part-time occlusion therapy, is the standard of care for children born with a visually significant unilateral congenital cataract (UCC)^1,2. Occlusion therapy of up to 50% of waking hours throughout the amblyogenic period using opaque adhesive patches is usually prescribed for children born with a unilateral cataract to minimize the development of deprivation amblyopia. Other types of therapy such as atropine penalization for amblyopia are typically not used in this population because of the severity of the amblyopia.

Although there are no randomized controlled trials of the efficacy of patching in children with deprivation amblyopia,³ the amount of time that parents report that their children wear the patch in the first year after surgery has been shown to be associated with improved visual outcomes, although there is substantial variability in visual outcomes associated with a particular amount of patching.⁴ Another potential benefit of part-time patching is expanded binocular visual fields.⁵ Visual acuity at age 4.5 has also been associated with the amount of time that children are patched between ages 12 and 54 months of age, but this association is not as strong as the association with patching in the first year after urgery.⁶ Thus, early patching is an important predictor of visual outcomes in children born with a unilateral congenital cataract likely because: (a) it establishes enduring patching habits; and (b) early patching improves visual outcomes, which make it easier for children to be patched later.

Even so, parents report difficulties maintaining the patching regimen⁷ and patching can be stressful for families.^8–10 The difficulty that families experience in adhering to prescribed patching therapy is evidenced by the fact that, on average, parents reported patching their children fewer than 4 hours per day throughout the first 54 months of life,⁶ even though patching of 5 to 6 hours would be closer to the prescribed 50% of waking hours. Additionally, prolonged occlusion of children with poor VA has been reported to adversely impact child behavior and increase parenting stress.^11,12

Many children who are born with a UCC never achieve good vision in their affected eye.^3,13,14 For example, in the Infant Aphakia Treatment Study (IATS) only one-quarter of children achieved a visual acuity (VA) of 20/40 or better, while 44% had VA of 20/200 or worse.¹³ Both unsuccessful treatment of UCC and no treatment result in poor vision in the affected eye. Given these outcomes, parents and providers may wonder at what age patching no longer has benefits for the child and if patching can be safely discontinued.

Antonio-Santos and colleagues found no evidence from trials to provide information about the recommended duration of treatment or the optimum occlusion regimen in children treated for unilateral congenital cataract.³ The goal of these analyses is to assess the extent to which early visual acuity measures are predictive of final visual outcomes, and the extent to which patching modifies this association. The intent is to assist parents and health care providers in determining whether to continue occlusion therapy once a reliable measure of optotype acuity can be obtained.

Methods:

These post hoc analyses leverage data from the Infant Aphakia Treatment Study (IATS).^13,15 The IATS was a multi-center, randomized controlled clinical trial of treatment for UCC. The primary objectives were to compare visual outcomes and adverse outcomes in children receiving an intraocular lens (IOL) at the time of cataract extraction relative to those left aphakic. Written informed consent from caregivers was obtained, and children provided assent at age 10.5 years. The study was approved by the institutional review boards of all participating institutions and was in accordance with the tenets of the Declaration of Helsinki.

Visual Acuity:

Monocular visual acuity was assessed every three months between 48 and 54 months of age using the Amblyopia Treatment Study (ATS)-HOTV protocol.¹⁶ Starting with the aphakic/pseudophakic eye, monocular visual acuity was tested with the child wearing his current refractive error correction. The eye not being tested was occluded using frosted occluder glasses (Good-Lite) to minimize the amplitude of latent nystagmus under monocular conditions.^17,18 Prior to 54 months of age, a member of the clinical center staff who had been trained by the study performed the assessment. At age 4.5 years (i.e., 54 months), a trained traveling tester conducted the assessment. We used the earliest measure of visual acuity obtained following this protocol for these analyses. At age 10.5 years, clinical center staff assessed optotype acuity using the E-ETDRS testing protocol.¹⁷ Additional details about the visual acuity testing at age 10.5 have previously been reported.¹³

Testers provided a general assessment of their confidence in the visual acuity measurement obtained for each eye, separately, at each visit. Testers provided their global assessment as very confident, somewhat confident, or not confident.

Since the implications of changes in visual acuity between the 5^th and 11^th year of life differ by a child’s visual acuity, we assessed changes in visual acuity and the impact of patching on visual acuity in four subgroups: near normal visual acuity in the treated eye (visual acuity of 20/40 or better); mild vision impairment (visual acuity of worse than 20/40 but 20/80 or better); moderate vision impairment (visual acuity worse than 20/80 but better than 20/200); and severe vision impairment (visual acuity of 20/200 or worse).

Patching:

Starting the second week after cataract extraction, patching of the fellow eye was prescribed for one hour a day for each month of life until the child was 8 months of age. Thereafter, patching was prescribed for 50% of waking hours and was prescribed until age 5. Patches were provided at no cost to patients until the child was 60 months of age. After age 5, clinicians prescribed patching based on their own clinical judgement and financial support for the patches was no longer provided.

Caregivers reported the amount of patching that a child received throughout the first five years of life. Soon after surgery and once per year, caregivers prospectively completed 7-day patching diaries. These diaries were mailed from the Data Coordinating Center (DCC) to the families two months after surgery and one month after each of the child’s birthdays. Additionally, semi-structured retrospective telephone interviews were conducted every three months.¹ The telephone interviews were conducted in the caregiver’s preferred language by a staff member at the DCC who was unaware of the child’s visual acuity. More than 90% of the interviews were conducted in English by the same staff member.

For the current analyses, the reported hours of patching per day were averaged over all assessments in five 12-month periods: the first year of life, ages 12 to 24 months, 24 to 36 months, 36 to 48 months and 48 to 54 months. In each period, the average amount of daily patching was categorized as minimal (<1/4 hours per day), moderate (1/4 to <2 hours per day) or more extensive (≥2 hours per day). The current analyses focus on patching in the 5^th year of life (i.e., between 48 and 60 months of age) as being a period after an optotype acuity was assessed. The period represents a time during which caregivers and healthcare providers would have information about the child’s visual acuity that might inform their decision on the amount of patching to perform.

Statistical Analysis:

Statistical analyses were conducted using SAS 9.4 (SAS, Cary, NC) and SPSS 29.0 (SPSS Inc., Arlington, VA). Changes in visual acuity were evaluated using both parametric tests including t-tests, analyses of variance (ANOVA) and linear regression, and non-parametric tests including Wilcoxon Rank Sum and Spearman Correlations. All P values were two-sided and not adjusted for multiple analyses.

Results:

Visual acuity results were available in both the 5^th (i.e., age 48 to 54 months) and 11^th (i.e., age 10.5 years) year of life for 108 participants. Three participants were excluded from the analyses: two patients had earlier vision-threatening adverse outcomes after which patching was not prescribed, and one participant had Stickler’s Syndrome and had better visual acuity in the treated than the fellow eye. Exclusion of these three participants’ data resulted in a final sample size of 105.

Most (n=88, 83.5%) of the children had an assessment of visual acuity made at the clinical visit closest to 48 months of age. Only 6 (5.7%) of the earliest visual acuity measurements were obtained at age 54 months. Visual acuity measures in the 5^th year of life were reliable, with a single measure intraclass correlation coefficient of 0.83 (95% CI 0.78,0.88). Further, the testers were very confident of their assessment of the earliest visual acuity measurement for nearly 90% of the children (Table 1), and they were very confident of the measurement for all but one child with visual acuity better than 20/200. However, the testers were very confident of the measured visual acuity for only about three-quarters of the children with visual acuity measurements of 20/200 or worse.

Table 1:

Association between Measured Visual Acuity at Age 4 and Tester Confidence in the Visual Acuity Measure in Participants in the Infant Aphakia Treatment Study (IATS)

	CONFIDENCE IN VISUAL ACUITY MEASURE AT AGE 4
VISUAL ACUITY AT AGE 4	Not Confident	Somewhat Confident	Very Confident	Total
20/40 OR BETTER	0 (0%)	0 (0%)	24 (100%)	24
>20/40 TO < 20/80	0 (0%)	1 (5.3%)	18 (94.7%)	19
20/80 TO < 20/200	0 (0%)	0 (0%)	19 (100%)	19
20/200 OR WORSE	3 (7.0%)	7 (16.3%)	33 (76.7%)	43
TOTAL	3 (2.9%)	8 (7.6%)	94 (89.5%)	105

At both 4 and 10.5 years of age, the median logMAR visual acuity of children who participated in the IATS was 0.88 (20/151) with 41% of all participants having visual acuity of 20/200 or worse (n=43 at age 4 and n=44 at age 10.5). On average, visual acuities at age 4 were predictive of visual acuities at age 10.5 (r_Spearman = 0.83 (p<0.01)) (Figure 1). Similarly, visual acuity at age 4 years was associated with visual acuity at age 10.5 years within groups defined by visual acuity at age 4 years (See Supplemental Figure 2).

Figure 1:

Scatter Plot of logMAR Visual Acuity at Age 4 by logMAR Visual Acuity at Age 10.5 Years

Half (n=52, 50%) of participants had poorer vision at age 10.5 than at age 4, and half had better vision (n=49, 47%) (Figure 2). However, most changes in visual acuity were small. More than one-third (n=40, 38%) of children had visual acuity at age 10.5 that was within 0.10 logMAR of the visual acuity measured at age 4 and 80% (n=84) had visual acuity that was within ±0.3 logMAR of the earlier measurement.

Of the 43 participants who had a visual acuity of 20/200 or worse at age 4, only 7 (16%) had a visual acuity better than 20/200 at age 10, and none had a visual acuity better than 20/100 (Table 2). Of the 19 children with visual acuity of 20/80 to better than 20/200, 1 (5%) had near normal visual acuity at age 10 and 2 (10.5%) had visual acuity between 20/40 and 20/80. One-third (n=6, 31.5%) of these children had a severe vision impairment at age 10.5. Among the 19 children who had visual acuity of worse than 20/40 but better than 20/80, 40% (n=8) had near normal visual acuity at age 10.5, and one third continued to have vision between 20/40 and 20/80. Only one of these children (5%) had a severe vision impairment at age 10.5 years. Of the 24 participants with visual acuity of 20/40 or better at age 4, 17 (70.8%) continued to have near normal vision at age 10.5, and only one was classified as having a severe vision impairment at age 10.5. We believe that the measurement at age 4 for this child (logMAR 0.20) is likely a measurement or recording error given that recorded vision at age 4.5 years (logMAR 1.39) was similar to that measured at age 10.5 (logMAR 1.34).

Table 2:

Optotype Visual Acuity Measures at Age 4 Years by Visual Acuity Measures at Age 10.5 Among Participants in the Infant Aphakia Treatment Study

		VISUAL ACUITY AT AGE 10
VISUAL ACUITY AT AGE 4		20/40 or better	>20/40 to <20/80	20/80 to <20/200	20/200 or worse	Total
	20/40 or better	17 (70.8%)	5 (20.8%)	1 (4.2%)	1 (4.2%)	24
	>20/40 to <20/80	8 (42.1%)	6 (31.6%)	4 (21.1%)	1 (5.3%)	19
	20/80 to <20/200	1 (5.3%)	2 (10.5%)	10 (52.6%)	6 (31.6%)	19
	20/200 or worse	0 (0.0%)	0 (0.0%)	7 (16.3%)	36 (83.7%)	43
	Total	26	13	22	44	105

Impact of Patching on Changes in Visual Acuity:

On average, children were patched 3.0 (± 2.6) hours per day between 48 and 60 months of age with half of the children (Interquartile range (IQR)) patching between 0.66 to 4.83 hours each day. Caregivers reported not patching 18 of the children at all during the fifth year of life (48–60 months of age), and 15 children were reportedly patched at least 6 hours per day with a maximum of 11 hours. Although the average amount of patching in the 5^th year of life was slightly lower than when the children were younger, earlier amounts of patching were strongly predictive of later patching. For example, patching between 36 and 48 months of age accounted for 80% (r_Pearson = 0.89, 95% CI 0.84,0.93) of the variation in patching in the 5^th year of life (i.e., between ages 48 and 60 months of age), and patching between 12 and 24 months accounted for one-quarter (26%, r_Pearson = 0.52, 95% CI 0.36,0.65 of the variation in patching in the 5^th year of life. Non-parametric correlations were nearly identical to parametric correlations.

As expected based on our earlier reports,⁴ the amount of patching that was reported by caregivers was associated with visual acuity. For example, children with visual acuity of 20/200 or worse at age 4 were patched, on average, fewer hours per day than children with visual acuity of 20/40 or better throughout the first five years of life. And children with near normal vision (i.e., visual acuity of 20/40 or better) averaged more hours of patching between 12 and 36 months of age than children in each of the other visual acuity groups (Table 3).

Table 3:

Visual Acuity at Ages 4 and 10.5 Years by Median (IQR) of Average Reported Hours of Patching per Day Among Participants in the Infant Aphakia Treatment Study

	20/40 OR BETTER	WORSE THAN 20/40 BUT BETTER THAN 20/80	20/80 TO BETTER THAN 20/200	20/200 OR WORSE	KRUSKALL-WALIS TEST1
	Visual Acuity at 4 Years 2
SAMPLE SIZE	24	19	19	43
<12 MONTHS	4.13 (3.22,5.09)	4.59 (3.50,5.15)	4.37 (2.60,5.99)	2.89 (1.98,4.38)	11.88 (p<0.01)
12 – 24 MONTHS	5.46 (2.78,5.60)	4.60 (4.08,5.58)	3.28 (1.77,4.52)	2.64 (0.95,4.32)	13.35 (p<0.01)
24–36 MONTHS	4.93 (2.63,5.72)	4.22 (3.85,6.00)	2.92 (1.21,4.80)	2.32 (1.17,4.19)	14.34 (p<0.01)
36–48 MONTHS	3.84 (0.84,6.46)	4.23 (3.02,6.11)	2.67 (0.90,4.76)	2.15 (0.41,3.45)	13.03 (p<0.01)
	Visual Acuity at 10.5 Years
SAMPLE SIZE	26	13	22	44	9.82 (p=0.02)
<12 MONTHS	4.13 (3.09,5.12)	4.78 (4.11,5.07)	4.19 (2.90,5.40)	2.90 (2.16,4.62)	10.43 (p=0.02)
12 – 24 MONTHS	4.12 (2.43,5.65)	4.81 (4.07,5.10)	3.93 (2.87,4.52)	2.51 (1.08,4.61)	12.43 (p<0.01)
24–36 MONTHS	4.59 (2.50,5.61)	4.49 (3.96,5.82)	3.28 (2.39,5.13)	2.22 (1.67,4.01)	10.84 (p=0.01)
36–48 MONTHS	3.61 (2.18,6.08)	4.79 (3.62,5.92)	3.57 (1.72,5.57)	2.37 (0.31,3.50)	9.30 (p=0.03)
48–60 MONTHS	3.45 (1.35,5.31)	4.58 (3.13,5.93)	3.21 (2.09,4.53)	1.26 (0.00,3.91)	9.30 (p=0.03)

¹3 degrees of freedom

²Data on the median reported average daily hours of patching between 48 and 60 months of age not shown for visual acuity at age 4 years since the patching would have occurred after the visual acuity measurement.

However, the average hours per day of patching in the 5^th year of life was not correlated with the change in visual acuity between age 4 and 10.5 years either overall (r_spearman = 0.002, p=0.99) or within subgroups defined by visual acuity at age 4 (Better than 20/40 r_Spearman = −0.16, p=0.47; Worse than 20/40 but better than 20/80 r_Spearman = 0.30, p=0.42; 20/80 to better than 20/200 r_Spearman = 0.15, p=0.40; 20/200 or worse r_Pearson = −0.15, p=0.37).

More hours of patching in the 5^th year of life (i.e., ages 48 to 60 months of age) was correlated with better visual acuity at age 10.5 in the overall sample (r_Pearson = −0.5, p=0.01). However, this correlation was limited to the group of children with visual acuity of 20/200 or worse (20/200 or worse r_Pearson = −0.27, p=0.11) and none of these children achieved a visual acuity of better than 20/100. There was no correlation between patching between 48 and 60 months of age and either visual acuity or change in visual acuity in any of the other three groups defined by visual acuity at age 4 (better than 20/40 r_Spearman = −0.14, p=0.53; worse than 20/40 but better than 20/80 r_Spearman = 0.22, p=0.39; and 20/80 to better than 20/200 r_Spearman = 0.22, p=0.34. (Figures 2 and 3).

Figure 3:

Distribution of Change in Visual Acuity (logMAR) between Age 4 and Age 10.5 Years.

Footnote: Values above 0 indicate worse vision at age 10.5 than at age 4. Values below 0 indicate improved vision at age 10.5 than at age 4.

Discussion:

We found that optotype visual acuity can be reliably obtained at age 4 in children treated for a unilateral congenital cataract, and that this visual acuity is predictive of the degree of a child’s vision impairment at age 10.5 years. For example, more than two-thirds of children remained in the same vision acuity group at age 10 as they were initially placed, and for forty percent (n=48) of the children, the visual acuity measured at age 10.5 years was within 0.15 logMAR of the measurement obtained at age 4. We also noted that none of the children with a visual acuity measurement of 20/200 or worse at age 4 achieved visual acuity of better than 20/100, irrespective of the amount of patching that was performed thereafter. This is in contrast to findings from our assessment of grating acuity at 12-months of age in which visual acuity measurements of less than 1.5 standard deviations from normal were only able to predict about 2/3rds of the children who would have optotype visual acuities of 20/100 or worse at 4.5 years of age.²⁰

We, and others, have reported on the importance of adherence to prescribed patching in achieving optimal visual outcomes in these children,^4,21,22 and the findings we report here confirm these associations. Children with near normal vision, on average, receive more patching each day than those with poorer vision. However, our findings also confirm earlier reports that there is a wide variation in the visual outcomes associated with specific amounts of patching. Further, the results presented here suggest that, to a large extent, visual outcomes in children treated for unilateral cataract are fixed by the time a reliable measure of optotype acuity can be obtained and that further patching is unlikely to significantly improve visual outcomes, particularly in children with poor vision.

We observed an association between more patching in the 5^th year of life (i.e., between 48 and 60 months of age) and better visual acuity at age 10.5 years only among children with the poorest vision at age 4. We suspect that at least part of this association is due to the difficulty in patching children with poor vision at age 4. Therefore, this association could be due to visual acuity predicting the amount of patching that these children were able to receive, rather than the amount of patching affecting the visual acuity, particularly since, even in this group, there was no association between patching in the 5^th years of life (i.e., 48 to 60 months of age) and a change in visual acuity. Given the difficulty of patching in this group, caregivers and providers may want to discuss the possible benefits of continued patching to achieve a visual acuity that likely won’t exceed 20/100 versus the impact of patching on their children’s lives and their relationships with their parents, particularly if parents report difficulty in adhering to prescribed patching.

Our findings also suggest that even among 4-year-old children with visual acuities between 20/40 and 20/80, about a third will likely end up with a visual acuity in this range. However, another 40% will end up with near normal vision. This information should provide a source of optimism for these families. We did note, however, that, even in this group, the amount of patching in the 5^th year of life was not associated with the final visual acuity outcome.

Finally, most children with near normal visual acuity at age 4 continued to have near normal vision at age 10. Relatively few of these children had discontinued patching by age 4. However, earlier reports suggest that visual acuity in this group is likely stable and may not decrease when a child is weaned from patching, particularly if the child’s visual acuity is closely monitored to minimize the likelihood of regression.²³ Further, we have reported that, among children with good visual acuities, those who have some evidence of stereopsis receive less patching than those who are patched more hours per day.^24–26 Therefore, it may be prudent to reduce the amount of time that patching is prescribed for children with near normal visual acuity so as to maximize the amount of binocular input that they experience without compromising their visual acuity.²⁷

This is the first study to systematically assess the association between patching and changes in visual outcome in children treated for unilateral congenital cataract. However, there are some key limitations to keep in mind. Specifically, the sample size, particularly in some subgroups, is relatively small. For example, there were only three children with visual acuity of 20/40 or better at age 4 who were reported to be patched fewer than 15 minutes per day in the 5^th year of life. Additionally, while patching of 50% of waking hours was prescribed for all IATS participants throughout the first five years of the study, few children achieved this level of patching. Although we have classified children who were patched an average of at least 2 hours per day as having “more extensive” patching, we recognize that most of these children are being patched much less than the 50% of waking hours that was prescribed. This finding is not unexpected as most research on adherence to occlusion therapy suggests that a substantial number of children do not receive the prescribed amount of patching.²⁸ We also note that parenting stress, child behaviors and visual outcomes have been reported to affect the amount of time that children are patched.²⁹ Additionally, the amount of patching that was prescribed after age 5 was left to the discretion of the clinician and may have been associated with both prior visual acuity and the change in visual acuity between the two time periods. We also note that visual field testing was not performed, so the potential impact of patching on the expansion of visual fields was not evaluated. ⁵ The presence of latent, fusional maldevelopment or infantile nystagmus syndrome may have influenced how much patching was prescribed for individual patients after age 5.¹⁷ We tested monocular visual acuity using a translucent occluder to reduce the image degradation from latent nystagmus. If visual acuity is not tested with a translucent occlude, vision may be assessed to be worse than it really is under binocular conditions. It should also be noted that for ten percent of children, testers were only somewhat confident or not confident about the visual acuity measurements obtained in the 5^th year of life. The tester might have felt that the measurements were inaccurate because of the child’s behavior. However, testers were very confident about the measurements obtained on all children with good vision and most (61 of 62) children with visual acuity better than 20/200. We believe that poor vision contributed to some testers’ concern about the validity of their acuity measurement. Overall, testers were very confident of the acuity measurement obtained on three-quarters of the children with a severe vision impairment in the affected eye. Further, we do not believe that this concern impacts our overall conclusions since it is likely that most of these children were unable to see well out of their treated eye, and the categorical results would be unaffected. Additionally, it is unclear what factors, beyond patching, adherence to refractive correction, and age at surgery ultimately determine the final visual outcome for this group of children. Therefore, we cannot be certain that we have adjusted for all the relevant confounding factors. Finally, while some children are able to complete optotype acuity testing at earlier ages, we cannot be sure that visual acuities at these earlier time points are as stable as visual acuity at or after age 4 appears to be.

In sum, these analyses provide important information to families and healthcare providers taking care of children with unilateral congenital cataract. First, our results suggest that optotype acuity measures in these children appear to be reliable in the 5^th year of life and that final visual outcomes in most of them can be predicted at that time. Additionally, our analyses suggest that once optotype acuity can be reliably measured, less aggressive patching protocols may be warranted in some children following surgery for unilateral congenital cataract after careful consideration of the potential impact of patching on the child’s quality of life, family relationships, and binocular visual field.

Supplementary Material

1

Figure S2: Scatter Plot of logMAR Visual Acuity at Age 4 by logMAR Visual Acuity at Age 10.5 Years Within Groups defined by Visual Acuity at Age 4.

Figure 4:

Boxplot of Visual Acuity at Age 10.5 Years by Visual Acuity Group at Age 4 Years and by Mean Minutes of Patching between 48 and 60 Months of Age

Figure 5:

Boxplot of Change in Visual Acuity Between Age 4 and Age 10.5 Years by Visual Acuity Group at Age 4 Years and by Mean Minutes of Patching between 48 and 60 Months of Age

Footnote: Values above 0 indicate worse vision at age 10.5 than at age 4. Values below 0 indicate improved vision at age 10.5 than at age 4.