Spectral-Domain Optical Coherence Tomographic Characteristics of Autosomal Recessive Isolated Foveal Hypoplasia

Figure 1. Pedigree of the family with isolated foveal hypoplasia. Both parents were healthy. Affected siblings with nystagmus, poor visual acuity, and isolated foveal hypoplasia (siblings 1, 4, 6, 8, and 10) are shaded in blue. Squares indicate males; circles, females.

Figure 2. Fundus photographs of 3 of 5 affected siblings with isolated foveal hypoplasia show normal optic discs with a poorly defined foveal region and loss of foveal pit. The central circular white reflex is an artifact. All 5 siblings had a normal anterior segment and normal multifocal electroretinographic findings. A, Fundus of the right eye in sibling 1, a 35-year-old man with visual acuity of 20/100 OU. B, Fundus of the right eye in sibling 4, a 30-year-old man with visual acuity of 20/70 OU. C, Fundus of the right eye in sibling 6, a 26-year-old woman with visual acuity of 20/70 OD and 20/100 OS.

Figure 3. Spectral-domain optical coherence tomographic scan showing the normal foveal anatomy and structural details. ELM indicates external limiting membrane; GCL, ganglion cell layer; ILM, internal limiting membrane; INL, inner nuclear layer; IPL, inner plexiform layer; IS/OS, inner photoreceptor segment/outer photoreceptor segment junction; NFL, nerve fiber layer; ONL, outer nuclear layer; OPL, outer plexiform layer; OPR, outer segment photoreceptor/retinal pigment epithelium complex; and RPE, retinal pigment epithelium. The dashed lines highlight the normal foveal pit (*), extrusion of plexiform layers (†), ONL widening (‡), and outer segment lengthening (§). Foveal grading is described as the following: grade 1, shallow foveal pit, presence of ONL widening, and presence of outer segment lengthening; grade 2, grade 1 but absence of foveal pit; grade 3, grade 2 but absence of outer segment lengthening; and grade 4, grade 3 but absence of ONL widening.³

Figure 4. Grade 4 foveal hypoplasia by spectral-domain optical coherence tomographic imaging in the right eyes of 3 of 5 affected siblings, including sibling 1 (A), sibling 4 (B), and sibling 6 (C). Grade 4 foveal hypoplasia is characterized by the absence of extrusion of plexiform layers, absence of foveal pit, absence of outer segment lengthening, and absence of outer nuclear layer widening. Scanning laser ophthalmoscopic imaging also demonstrates the lack of a well-defined foveal area. I indicates inferior; N, nasal; S, superior; and T, temporal.