Abstract
Purpose:
To evaluate the clinical diagnostic performance of retinal nerve fibres layer (RNFL) analysis by optical coherence tomography (OCT) as an adjunctive screening technique for the detection of optic pathway gliomas (OPG) in pediatric patients affected by neurofibromatosis type 1 (NF1).
Methods:
One hundred thirty consecutive pediatric patients (2-16 years old) affected by NF1 were enrolled. Patients underwent visual function assessment (Hyvarinen symbols chart and/or Snellen charts) and optic disc evaluation by indirect ophthalmoscopy (performed by an experienced, masked pediatric ophthalmologist). Spectral domain OCT was performed to assess retinal nerve fiber layer thickness (Spectralis, Heidelberg, Germany). Patient with the alteration of at least one single test underwent orbital/brain MRI.
Results:
33 of 130 enrolled patients (25%) showed an alteration of at least one single performed test. 29 patients (88%) showed decreased RNFL thickness by OCT (compared to age-based norms), 19 (58%) showed optic disc alterations suspected for the presence of OPG and 13 (45%) showed decreased BCVA (compared to age-based norms). MRI confirmed the presence of OPG in 29 (88%) of 33 clinically suspected patients. Twenty-six of them (89%) showed decreased RNFL thickness by OCT. Sensitivity and positive predictive value of each test were, respectively: 0.93 and 0.93 for OCT, 0.89 and 0.59 for optic disc evaluation, 0.46 and 0.76 for visual acuity. The correlation between test positivity and the presence of disease was not significant for optic disc evaluation (p=0.74), borderline for visual acuity (p=0.07), and statistically significant for RNFL analysis by OCT (p=0.003).
Conclusions:
RNFL analysis by OCT is superior to standard OPG screening techniques also in a routine clinical setting, allowing to detect about 30% more lesions compared to traditional screening methods.