Purpose
To describe the visual outcomes of a large cohort of pediatric patients presenting to a tertiary care pediatric hospital with first-episode optic neuritis.
Design
Retrospective, observational cohort study.
Methods
In a tertiary care pediatric hospital, patients with first-episode optic neuritis and at least 3 months of follow-up over a 10-year period were assessed and followed-up in the ophthalmology department. The main outcome measures were visual acuity at 3 months and 1 year of follow-up, with analysis of risk factors for poor visual outcomes and the time course of visual recovery.
Results
Of the 59 pediatric patients with first-episode optic neuritis, 46 had at least 3 months of follow-up and 36 had at least 1 year of follow-up. The mean age was 12.6 years old; 72% were female, 41% had bilateral involvement, 52% had or developed an underlying diagnosis (39% multiple sclerosis, 7% acute disseminated encephalomyelitis, 7% neuromyelitis optica), and 91% received treatment (85% steroids, 7% multimodal). At 1 year, 81% were at least 20/20 and 89% were at least 20/40. A poor visual outcome at 1 year (<20/40) was associated with vision of <20/20 at 3 months ( P = 0.041). Other clinical characteristics, including visual acuity at presentation, sex, bilateral involvement, optic nerve edema, and underlying diagnoses were not significantly associated with poor visual outcomes.
Conclusions
In this cohort of pediatric patients with optic neuritis, the majority of patients regained normal visual acuity at 1 year, regardless of baseline clinical characteristics.
Optic neuritis is an inflammatory disorder of the optic nerve that can be idiopathic or associated with recurrent demyelinating conditions such as multiple sclerosis (MS). Optic neuritis most commonly affects young adults, but approximately 5% of cases occur in children. Optic neuritis in the pediatric population has several important distinctions from optic neuritis in adults. For instance, observational studies have consistently shown that optic neuritis in children is more often bilateral, optic nerve edema is more common, and patients are less likely to report pain with eye movement.
The risk for developing MS after an episode of optic neuritis may also be different in children compared to adults. In the adult population, the landmark Optic Neuritis Treatment Trial (ONTT) followed patients for 15 years after each experienced an episode of optic neuritis and found that the overall risk for developing MS was 50% (25% with no lesions on baseline magnetic resonance imaging (MRI) and 72% with 1 or more lesions on MRI). In contrast, Waldman and associates performed a meta-analysis of 14 observational studies of optic neuritis in children and estimated that the risk for developing MS was 19% after a mean follow-up of 6.3 years.
Although the risk for MS after optic neuritis in children has been reported in many observational studies, few have looked specifically at visual outcomes. The purpose of this study was to describe the clinical characteristics and visual outcomes of a large cohort of pediatric patients presenting to a tertiary care pediatric hospital with first-episode optic neuritis.
Methods
This study was approved prospectively by the Institutional Review Board at Boston Children’s Hospital. The design of the study was a retrospective, observational cohort study. The setting of the study was a tertiary care pediatric hospital. A search of the electronic medical records was conducted for all patients who were seen by the ophthalmology service for optic neuritis between 2002 and 2012.
During the study period, 59 patients presented with first-episode optic neuritis. The diagnosis of optic neuritis was made by expert clinical judgment, which included assessment of visual acuity, visual fields, pupils, and dilated fundoscopy. Each of the patients in the study received an MRI to assess for demyelinating lesions and rule out other potential causes, but specific MRI findings were not required for the diagnosis. The electronic chart of each patient was reviewed independently by 2 of the coauthors (M.W. and A.O.). Patients were included in the study if they presented with first-episode optic neuritis and had at least 3 months of follow-up data available. Patients were excluded if there was any uncertainty in the diagnosis, if there was a potentially confounding factor that could have affected vision (eg, amblyopia, hereditary optic neuropathy or malignancy) or if there was any evidence of a previous episode of optic neuritis (from history or on examination). Patients who had a known demyelinating condition such as MS or neuromyelitis optica were not excluded, provided there was no indication of a prior episode of optic neuritis.
The main outcome measure was visual acuity. For the purpose of analysis, visual outcomes were grouped into 2 predetermined follow-up intervals: 3 months (range, 2–4 months) and 1 year (range, 10–14 months). However, all available follow-up data were examined in order to determine whether patients received treatment, whether an underlying demyelinating disorder was eventually diagnosed (eg, MS) and whether patients recovered normal visual acuity (≥20/20) at any point during follow-up.
A poor visual outcome was defined as vision <20/40 (in the affected eye in unilateral cases and in the eye with worse visual acuity at presentation in bilateral cases). The Fisher exact test was used to determine whether there were any univariate associations between clinical characteristics and a poor visual outcome at 3 months or 1 year. A 2-tailed t test with unequal variance was used for group comparisons of the mean time from presentation to recovery of normal visual acuity. Survival analysis was used to further analyze the time to visual recovery. A P value of less than 0.05 was considered statistically significant. The statistical analysis was conducted using Stata Statistical Software v 13 (IBM, College Station, Texas, USA).
Results
Of the 59 patients who presented with first-episode optic neuritis during the study period, 13 did not meet the study criteria and were excluded from further analysis (9 had inadequate follow-up, 3 had potentially confounding conditions, and 1 had evidence of pre-existing optic atrophy). The 46 remaining patients were included in the study. The mean age of the patients was 12.6 years of age; 72% were female, 41% had bilateral involvement, 52% had or developed an underlying diagnosis, and 91% received immunomodulatory treatment (see Table 1 for baseline characteristics and Table 2 for clinical features).
| Age (Years) | |
| Mean | 12.6 |
| Range | 3.9–18.8 |
| Female (%) | 33 (72) |
| Treatment | |
| Intravenous corticosteroids with oral taper (%) | 30 (65) |
| Intravenous corticosteroids (%) | 9 (20) |
| Steroids combined with intravenous immunoglobulin, plasma exchange or both (%) | 3 (7) |
| No treatment (%) | 4 (9) |
| Underlying diagnosis | |
| Isolated optic neuritis (%) | 22 (48) |
| Multiple sclerosis (%) | 18 (39) |
| Acute disseminated encephalomyelitis (%) | 3 (7) |
| Neuromyelitis optica (%) | 3 (7) |
| Clinical Finding | Number (%) |
|---|---|
| Average duration of symptoms prior to presentation (days) | 7 |
| Bilateral involvement | 19 (41) |
| Subjective loss of visual acuity | 45 (98) |
| Pain with eye movement | 20 (43) |
| Headache | 18 (39) |
| Color vision deficit | 29 (63) |
| Color vision intact | 7 (15) |
| Vision too poor to measure | 10 (22) |
| Optic nerve edema | 31 (67) |
| Relative afferent pupillary defect in unilateral, n = 27 | 27 (100) |
| Relative afferent pupillary defect in bilateral, n = 19 | 9 (47) |
| Visual acuity (worse eye if bilateral) | |
| ≥20/20 | 1 (2) |
| <20/20–≥20/40 | 6 (13) |
| <20/40–≥20/200 | 16 (35) |
| <20/200–>counting fingers | 4 (9) |
| Counting fingers-no light perception | 19 (41) |
The primary outcome measure was visual acuity as determined by the affected eye in unilateral disease and the worse-seeing eye at presentation in patients with bilateral disease. Of the 46 patients with at least 3 months of follow-up, 36 had at least 1 year of follow-up data available. At 3 months, 67% of the patients were at least 20/20, and 89% were at least 20/40. At 1 year, 81% were at least 20/20, and 89% were at least 20/40 ( Table 3 ). Only 4 of the 36 patients (11%) had visual acuities worse than 20/40 1 year after presentation ( Table 4 ). In the better-seeing eye at presentation in cases of bilateral optic neuritis, 14 of the 15 patients seen at 1 year had 20/20 vision, and 1 patient had vision of 20/400 due to a recurrence in that eye.
| Visual Outcomes (Worse Eye at Presentation if Bilateral) | Visual Acuity at 3 Months n = 46 (%) | Visual Acuity at 1 Year n = 36 (%) |
|---|---|---|
| ≥20/20 | 31 (67) | 29 (81) |
| <20/20–≥20/40 | 10 (22) | 3 (8) |
| <20/40–≥20/200 | 3 (7) | 3 (8) |
| <20/200–>counting fingers | 1 (2) | 0 (0) |
| Counting fingers to no light perception | 1 (2) | 1 (3) |
| Age | Sex | Laterality | Optic Nerve Edema | Underlying Diagnosis | Treatment | Visual Acuity (Worse Eye If Bilateral) | |
|---|---|---|---|---|---|---|---|
| Presentation | 1 year | ||||||
| 8 | Male | Unilateral | No | Acute disseminated encephalomyelitis | Steroids | 20/1600 | 20/50 |
| 9 | Female | Unilateral | Yes | Isolated optic neuritis | Steroids | 20/400 | 20/50 |
| 11 | Female | Bilateral | No | Multiple sclerosis | Multimodal a | Light perception | Hand motion |
| 14 | Female | Unilateral | Yes | Multiple sclerosis | Multimodal a | No light perception | 20/200 |
a Treatment with intravenous immunoglobulin or plasma exchange if response to systemic steroid treatment was felt to be inadequate.
The only factor associated with a poor visual outcome at 1 year (<20/40) was visual acuity <20/20 at the 3-month follow-up interval ( P = 0.041, odds ratio = 13). Other clinical characteristics, such as visual acuity at presentation, sex, bilateral involvement, optic nerve edema, treatment, and underlying diagnosis, were not significantly associated with a poor visual outcome ( Table 5 ).
