Absent Foveal Pit, Also Known as Fovea Plana, in a Child without Associated Ocular or Systemic Findings

Figure 2

Images of both eyes of the case (top) and a control subject (bottom) obtained with spectral domain optical coherence tomography (OCT). The grayscale images are complemented with a colour-coded slice of the foveal pit (control) or the presumed anatomical location of the fovea (case). The horizontal cross-section corresponds to a horizontal section of the retina that is marked in the red-free fundus image with number 1; the OCT section shows absence of normal foveal pit in the case. All inner retinal layers are seeing crossing the anatomic foveal centre. The images of the case (top images) show a slightly thicker photoreceptor outer nuclear layer at the centre, surrounded by a ganglion cell layer that is thicker than at more peripheral locations (central ring of the retinal image), confirming the centration of this scan on the location of the anatomical fovea. Outer photoreceptor structures, such as the inner-outer segment layer and the interdigitation between the photoreceptor outer segments and the apical retinal pigment epithelium, have a normal appearance. Maps of total retinal thickness (overlapped with retinal image) show a nasal-to-temporal gradient of retinal thickness but the relative thicker parafoveal region is missing (also visible when compared with the control subject, bottom images). Of notice, the fixation position in right eye (the central ring) seems to be shifted, below the level of the optic disc. Whilst this observation might be an effect of the picture, it might also be another functional sign of an “immature” fovea and a possible explanation to more reduced vision in the right eye than the left eye. The image at the top-left corner can be used as a “legend” to analyse the OCT findings. In that legend, (a) extrusion of plexiform layers; (b) foveal pit; (c) out-segment (OS) lengthening; and (d) out nuclear layer (ONL) widening; this legend has been adopted from [7].