Screening children with NF1 for optic pathway glioma--No

Prevalence of Strabismus Among Children With Neurofibromatosis Type 1 Disease With and Without Optic Pathway Glioma

PURPOSE

To evaluate the prevalence of strabismus in neurofibromatosis type 1 (NF-1) by comparing children with normal neuroimaging to those with optic pathway glioma.

METHODS

A retrospective data collection of all children with NF-1 with neuroimaging studies examined at a single medical center between 2000 and 2016.

RESULTS

Of the 198 children with NF-1 reviewed, 109 (55%) were male, 121 (61%) had normal neuroimaging, and 77 (39%) had an optic pathway glioma. Mean age at presentation was 6.3 ± 4.7 years and mean follow-up was 4.8 ± 3.1 years. Strabismus was present in 29 (15%) children and was significantly more prevalent in children with NF-1 with optic pathway glioma (21 of 77 [27%]) than in those with normal neuroimaging (8 of 121 [7%], P < .001). Sensory strabismus was only found in children with optic pathway glioma, accounting for most cases (12 of 21 [57%]). A strong association between strabismus and optic pathway glioma is demonstrated by an odds ratio of 5.29 (P < .001). Children with NF-1 with optic pathway glioma have a 4.13 times higher relative risk of developing strabismus than children with NF-1 without it (P = .001). The direction of ocular misalignment in children with NF-1 with optic pathway glioma was not significantly different than that observed in children without optic pathway glioma (P = .197, Fisher's exact test). Only 5 (17%) children with NF-1 with strabismus (3 with optic pathway glioma) underwent corrective surgery to align their eyes.

CONCLUSIONS

Optic pathway glioma in children with NF-1 is associated with an increased risk of strabismus that is often sensory. Although exotropia is the most common ocular misalignment associated with optic pathway glioma, the direction of strabismus cannot be used as an accurate predictor for its presence. [J Pediatr Ophthalmol Strabismus. 2019;56(1):19-22.].

Comparative study of the ophthalmological examinations in neurofibromatosis type 1. Proposal for a new screening algorithm

PURPOSE

Efforts are made to unify the protocol concerning the ophthalmological screening, monitoring and treatment of Optic Pathway Gliomas (OPGs) in children with neurofibromatosis type 1 (NF1). The aim of this study is to compare the most recent recommendations published in 2007 with the screening strategies in NF1 centres. The integration of these data resulted into a recommendation for an improved screening strategy.

METHODS

A literature search on PubMed between 1984 and 2013 was performed. A questionnaire on the ophthalmological screening in NF1 was sent to centres of expertise in the field of NF1. Literature and questionnaire data were analysed. Also, findings of a round table discussion on the ophthalmological screening of NF1 patients at the European Paediatric Ophthalmological Society (EPOS) meeting in 2013 were summarized.

RESULTS

In most centres ophthalmological screening in NF1 patients is well organized, but is performed longer and at more regular intervals than is mentioned in the recommendations. Visual acuity testing, fundoscopy and pupillary reflexes are carried out unanimously.

CONCLUSIONS

There is no uniformity of the ophthalmological screening in NF1 patients. The present recommendation advises to screen annually until the age of 8. Because OPGs are likely to develop before the age of 6 and children do not usually complain of visual problems, OPGs can be missed or detection can be delayed if screening is only yearly performed at this young age. Based on these arguments, about half of our responders screen more frequently and until a later age. Therefore, we suggest performing a six monthly screening until the age of 6 and a yearly examination from 6 years until adulthood. This examination should include visual acuity assessment, pupillary reflexes and a fundoscopy.

Ophthalmological assessment of children with neurofibromatosis type 1

Neurofibromatosis type 1 (NF1) is a common autosomal dominant disorder, caused by mutations in the NF1 gene, located on chromosome band 17q11.2. In 1988, the National Institutes of Health created specific criteria for the diagnosis of NF1. Four cardinal criteria are assessed through ophthalmological screening: Lisch nodules, optic pathway glioma, a distinctive osseous lesion (sphenoid dysplasia), and the (orbital) plexiform neurofibroma. NF1 patients are prone to the development of central and peripheral nervous system tumors. Especially young children are at risk for growing optic pathway gliomas that can threaten their sight. From an early age, children with NF1 undergo regular ophthalmological examinations. Little is known about the natural progress of these clinical features and the guidelines for screening and follow-up are controversial. Several questions remain unanswered.

CONCLUSION

Most of these questions could be solved by better understanding of the natural history of optic pathway gliomas. There is a tendency towards using vision as a primary objective in clinical treatment trials; this way we can evaluate new treatment strategies and focus specifically on visual evolution so we will be able to select even more carefully which patient would benefit treatment. For future clinical trials, a standardized visual acuity assessment protocol is therefore mandatory.

Role of visual evoked potentials in the assessment and management of optic pathway gliomas in children

OBJECTIVE

The aim of this study is to investigate the role of pattern reversal visual evoked potentials (pVEPs) in the screening and monitoring of optic pathway gliomas (OPGs) in children with and without neurofibromatosis type 1.

METHODS

A review of the English literature published between 1980 and 2012 was performed, with comparison of results of retro- and prospective studies.

RESULTS

Pattern reversal VEPs have a high sensitivity (85.7-100 %) for the diagnosis of OPGs, moreover they are safe and cost-effective. Conversely, they have a low specificity (43-83 %) and are not widely available. Besides, pattern reversal VEP results can be unreliable in young children, because of the need for a good cooperation. The studies that were analyzed have drawbacks, including the small sample size, the retrospective design, the differences in gold standard for diagnosis, the different interpretation of small changes in VEP results and the lack of control groups.

CONCLUSION

There is still debate about the gold standard for the screening and follow-up of OPGs. The added value of pVEPs to the ophthalmic examination is controversial. Randomized controlled trials or prospective multicentre studies are necessary to assess with sufficient accuracy the sensitivity and specificity of pattern reversal VEPs in the screening for OPGs and its follow-up.

Visual loss in orbitofacial neurofibromatosis type 1

PURPOSE

On occasion, neurofibromas in neurofibromatosis type 1 may be present on the lid, brow, or face of an infant or child, a circumstance commonly referred to as "orbitofacial neurofibromatosis" (OFNF). The present study evaluates the causes and extent of visual loss in a group of patients with OFNF.

DESIGN

Case series.

PARTICIPANTS

Fifty-five patients with OFNF.

METHODS

Retrospective medical record review and reexamination of selected patients from one institution.

MAIN OUTCOME MEASURES

Visual acuity and identification of underlying cause of reduced vision.

RESULTS

Fifty patients with unilateral OFNF (23 male, 27 female, aged 4-48 years at last visit) and 5 patients with bilateral OFNF (2 male, 3 female, aged 15-43 years) had adequate information available to assess afferent visual functioning. Nine patients (4 male, 5 female, aged 4-28 years) had optic pathway glioma (OPG) in addition to OFNF. Patients were followed as long as 27 years (mean 8.4 years). Thirty-nine patients (71% of total) had visual acuity of ≤20/60 on the side of OFNF involvement (or the side of worse OFNF involvement in patients with bilateral disease). One or more causes of amblyopia were present in 29 of these patients, 19 patients had organic disease of the eye (e.g., glaucoma or retinal detachment) or the afferent system (e.g., OPG), and 12 patients had correctable refractive errors.

CONCLUSIONS

Visual loss in this OFNF cohort was common, typically profound, and usually multifactorial. Some causes of visual loss (including congenital glaucoma with buphthalmos and retinal detachment, disconjugate gaze due in part to distorted skull development causing strabismic amblyopia, and OPG) were difficult to treat adequately and tended to cause progressive, profound visual loss. Therefore, careful observation should be made during the period of visual immaturity for possible causes of amblyopia that might be treatable, such as refractive changes, occlusion of the visual axis, or congenital glaucoma. As affected individuals get older, physicians must be vigilant for the progression of optic nerve disease due to glaucoma or OPG and to the possibility that vision might be improved by refraction.

Orbitofacial neurofibromatosis: clinical characteristics and treatment outcome

PURPOSE

To report clinical observations and surgical management in a large series of patients with orbitofacial neurofibromatosis type 1 (OFNF).

PATIENTS AND METHODS

Patients were identified and medical records reviewed for demographic data, ophthalmologic examinations, surgical interventions, and procedure outcome to create a retrospective, non-comparative case series of patients with OFNF seen at one medical centre over a 23-year period.

RESULTS

Sixty patients with OFNF (31 females and 29 males; mean age, 14 years) were followed for an average of 5.7 years. Presenting signs and symptoms included eyelid swelling in all patients, ptosis in 56 (93.3%), proptosis in 34 (56.6%), dystopia or strabismus in 30 (50%), and decreased visual acuity in 50 (83.3%). Surgical intervention included ptosis repair in 54 (90%; mean 1.6 surgical procedures), facial and orbital tumour debulking in 54 (90%; mean 2.3 surgeries), and canthoplasty in 28 (46.6%) patients. Eleven patients required enucleation or exenteration of a blind eye.

CONCLUSION

Patients with OFNF often require multiple procedures to preserve vision, prevent additional disfigurement, and achieve cosmetic rehabilitation. Patients need regular ophthalmological monitoring given the potential for progressive visual and cosmetic consequences.