Abstract
Purpose:
To describe the ocular and optical-coherence tomography (OCT) findings in patients with microcephaly.
Methods:
Twenty-two patients with microcephaly (mean age 13.1 years) underwent an ophthalmological examination and handheld OCT (Bioptigen Inc., USA). The tomograms were imported into ImageJ software where manual retinal layer segmentation was performed. The thickness of the central foveal retina, perimacular retina (1 mm temporal and 1 mm nasal to the fovea) and individual foveal layers were quantified and compared to 22 age-matched healthy controls.
Results:
Six patients had microcephaly, lymphoedema and chorioretinal dysplasia (MLCRD), two patients had possible progressive encephalopathy with edema, hypsarrythmia and optic atrophy (PEHO-syndrome) and one patient had microcephaly with pontine and cerebellar hypoplasia (MICPCH-syndrome)). In five patients there was an autosomal recessive pattern of inheritance, four patients had isolated, non-syndromic microcephaly and in the remaining four patients the microcephaly could not be classified. Ocular abnormalities were found in fifteen out of 22 subjects (68%). The most common findings were strabismus (45%), and nystagmus (36%). Other ocular anomalies included retinal pigment epithelial changes, optic nerve hypoplasia, amblyopia, significant refractive errors, chorioretinal dysplasia with punched-out lesions and retinal folds. The perimacular retinal thickness was significantly reduced in the microcephaly group compared to the control group: nasal to the fovea (296.98 microns vs. 343.82 microns, p<0.001) and temporal to the fovea (268.41 microns vs. 324.66 microns, p<0.001). There was also thinning of the ganglion cell layer (GCL) nasal to the fovea (41.23 vs. 53.32 microns, p<0.001) and temporal to the fovea (30.72 vs. 46.80 microns). Additionally, the inner plexiform layer nasal to the fovea (40.68 vs. 47.45 microns, p=0.028), the outer nuclear layer temporal to the fovea (51.34 vs. 67.54 microns, p=0.015) and the inner segment of the photoreceptors temporal to the fovea (19.62 vs. 25.98 microns, p=0.0036) were thinner in microcephaly. Five patients had foveal hypoplasia.
Conclusions:
Ocular anomalies, especially strabismus, nystagmus and retinal abnormalities are frequent in microcephaly.The perimacular retina and the GCL were thinner on OCT. Patients with microcephaly due to heterogeneous aetiology have significant retinal pathology and share specific OCT findings.
Keywords: 612 neuro-ophthalmology: diagnosis •
696 retinal degenerations: hereditary •
552 imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)