A fingerprint on the retina

Case – A 3-year-old boy was referred for poor vision and to-and-fro movement of eyes since early infancy. The best corrected visual acuity was 4/60 in both eyes, with a refractive correction of +3 D cylinder at 90°. The patient had pendular nystagmus in both eyes. Fundus examination revealed diffusely hypopigmented retinal pigment epithelium. Interestingly, fingerprint-like markings were seen at the macula in both eyes when imaged with Optos pseudocolor imaging [Fig. 1a and b].Figure 1: (a) and (b) Pseudocolor Imaging of fundus showing fingerprint like markings at the macula. (c) and (d) Spectral-domain ocular coherence tomography (SD-OCT) shows absence of foveal dip, loss of normal thinning of fovea, and continuation of inner retinal layers across fovea, suggestive of foveal hypoplasiaWhat would be your next step? OCT angiography OCT Fundus autofluorescence Fluorescein angiography Illustrations– Fig. 1(a), (b), (c), and (d) Findings – Spectral-domain optical coherence tomography (SD-OCT) showed the absence of foveal dip, loss of normal thinning at the fovea, and continuation of inner retinal layers across the fovea, suggestive of foveal hypoplasia [Fig. 1 c and d]. Pendular nystagmus, diffusely hypopigmented retinal pigment epithelium, and foveal hypoplasia pointed out the diagnosis of ocular albinism, and the patient was advised photochromatic glasses. Diagnosis – Ocular albinism Correct answer – (B) OCT. Fingerprint artifact is known to occur in Optos imaging in cases with nystagmus where red and green scanning lasers produce a compressed and expanded image at the fovea due to non-uniform scan velocities. Therefore, it is important to understand the artefactual nature to not confuse it with a sinister macular lesion.[1] This imaging can be used to identify foveal hypoplasia in settings when OCT is not possible due to nystagmus. Discussion – Albinism is a genetic, heterogenous, hypopigmentary disorder. It is of two types: oculocutaneous albinism with variable degrees of involvement of the eyes, skin, and hair; and the less common ocular albinism, with disease involvement limited to the eyes. Ocular features of this disorder include nystagmus, refractive error, photophobia, strabismus, iris transillumination, and foveal hypoplasia.[2,3] The visual acuity is usually impaired due to foveal hypoplasia. It has various systemic associations, including Chedaik-Higashi syndrome, Hermansky-Pudlak syndrome, and Waardenburg syndrome. Financial support and sponsorship: Nil. Conflicts of interest: There are no conflicts of interest.