Optic nerve abnormalities in children: a practical approach

How to use…the direct ophthalmoscope

Ophthalmoscopy and red reflex examination are core medical skills required to identify sight-threatening and life-threatening disease. We discuss the predictive utility and limitations of findings with an ophthalmoscope and tips as to how to optimise these. We outline important considerations in three clinical scenarios: an abnormal red reflex, an abnormal optic disc and retinal haemorrhages in the context of child protection concerns.

Macular optical coherence tomography in patients with unilateral optic nerve hypoplasia

PURPOSE

To characterize the extent and location of macular thinning in patients with unilateral optic nerve hypoplasia (ONH) as compared to the contralateral normal eye.

METHODS

The medical records of patients with unilateral ONH who underwent spectral domain optical coherence tomography (SD-OCT) of the macula were retrospectively reviewed. SD-OCT scans were manually segmented by 3 observers in 3 macular regions (superior, central, inferior). Boundaries identified included the inner limiting membrane, the junction between the inner nuclear layer and outer plexiform layer, and the neural retina-retinal pigment epithelium interface. Using custom MATLAB software, inner and outer retinal thickness profiles were quantified. A paired t test was used to compare the retinal thickness between the ONH eye and the contralateral normal eyes.

RESULTS

Inner retinal thickness of the ONH eye was decreased in all areas of the macula (superior, central, and inferior) compared to the contralateral normal eye (P < 0.05). Outer retinal thicknesses were also decreased in the central and inferior sections compared with the normal eye (P < 0.05).

CONCLUSIONS

Optic nerve hypoplasia is a congenital disease known to result in thinning of the nerve fiber and ganglion cell layer. Our small cohort demonstrated thinning of the inner retinal layers as well as the outer retinal layers in the ONH eye compared with the contralateral normal eye.

Optic nerve hypoplasia in children and adolescents; prevalence, ocular characteristics and behavioural problems

PURPOSE

To report prevalence, ocular characteristics and coexisting behavioural problems in children and adolescents with optic nerve hypoplasia (ONH), which is a common cause of visual impairment in children in western countries, often associated with neurological or endocrinological problems and where autism has been reported in severe cases with blindness.

METHODS

This is a population-based cross-sectional study of patients <20 years of age who had been diagnosed with ONH and lived in the county of Stockholm in December 2009. Ophthalmological assessments including fundus photographs with optic disc analyses were made. A questionnaire was used to screen for behaviour and development.

RESULTS

The prevalence of ONH in all living children <18 years of age in Stockholm was 17.3/100 000 with a prevalence of visual impairment (<0.3) of 3.9/100 000. In total, 66 patients, median age 9.3 years (0.6-19.4), 36 with bilateral and 30 with unilateral ONH, were included in the current study; 53 were re-examined clinically, group A, and 13 agreed to retrospective analyses of existing medical records, group B. Analyses of the optic discs were made in fundus photographs from 53 patients comparing a semi-automated (Retinal Size Tool) and a manual method (Zeki). There was a strong curvilinear correlation (r(S)  = -0.91 p < 0.0001 for both eyes). Behavioural problems were more common (p < 0.05) in bilateral ONH.

CONCLUSION

Optic nerve hypoplasia is a common ocular malformation with a prevalence of 17.3/100 000 children and adolescents <18 years of age in Stockholm. Unilateral ONH seems as common as bilateral.

Anomalous Vascular Patterns of the Optic Disc in Amblyopia

PURPOSE

To evaluate the presence of anomalies of the optic disc vascular patterns in subjects with amblyopia.

DESIGN

Case controlled study. The outcome measure is temporal deviation of central retinal vessels and / or vascular pattern asymmetry.

METHODS

A total of 342 hyperopic amblyopic patients were evaluated. An additional 88 subjects with equal visual acuity with strabismus, and 108 subjects with equal visual acuity and anisometropia were evaluated.

RESULTS

In this study, more than 50% of amblyopic patients had optic disc deformities. Sixty-five percent of subjects with amblyopia, orthophoria, and anisometropia exceeding 1.5 D had these anomalies compared with less than 7% of the groups without amblyopia or strabismus.

CONCLUSIONS

These disc anomalies may be associated with disorganization of optic nerve axons. This finding indicates the possibility of a peripheral cause for impaired vision and could provide an explanation for the variability in visual defects associated with amblyopia. Optic nerve imaging should be incorporated into clinical protocols for amblyopia research.