Retinal Morphology in Sjögren-Larsson Syndrome on OCT: From Metabolic Crystalline Maculopathy to Early-Onset Macular Degeneration

Abstract

To study long-term macular changes by spectral-domain (SD) OCT in patients with Sjögren-Larsson syndrome (SLS). Retrospective cohort study. Twenty-two patients with genetically proven SLS (12 female, 10 male; median age, 21 years; range, 3-47 years) were included in the study. One or more SD-OCT scans were available from the period 2008 to2017. Seventeen patients underwent SD-OCT imaging of the macula in 2017. Earlier scans were available of the other 5 patients. The latest available SD-OCT scans were qualitatively assessed for morphologic changes in 19 patients. In addition, retinal layer thickness could be measured in 15 patients. The latest scans were compared with previous scans to assess the course of the disease qualitatively (n = 15 patients) and quantitatively (n = 10 patients). Macular morphology and retinal layer thickness on SD-OCT scans during the study period. In all patients, abnormal macular morphology was observed in both eyes, already from the youngest age. Intraretinal crystals, visible as hyperreflective dots, were visible in all eyes and located in the retinal nerve fiber layer, inner plexiform layer, and outer plexiform layer. Furthermore, the photoreceptor (PR) layer lacked the physiologic thickness amplification beneath the fovea. Pseudocysts with limited interruption of the underlying PR layer were observed in half of the patients, all younger than 30 years of age. Frank atrophy of the retinal pigment epithelium (RPE) and a neovascular complex were seen in 3 older patients and 1 older patient, respectively. The fovea was significantly thinner compared with healthy controls and decreased even further during the study period. Macular dystrophy in SLS may initially comprise an arrest in foveal development. Because of the absence of macular pigment, phototoxic damage may then cause central retinal degeneration of the vulnerable macula, marked by the development of pseudocysts. Eventually, the young adult patients may proceed to an early-onset end-stage macular degeneration with frank atrophy of the RPE or neovascularization.