Electrophysiological assessment for early detection of retinal dysfunction in ß-thalassemia major patients.

PURPOSE: The purpose of this study was to assess the role of various diagnostic tests in early detection of retinal changes in ß-thalassemia major patients. METHODS: Thirty-eight visually asymptomatic ß-thalassemia major patients receiving regular blood transfusions and iron-chelation therapy with deferoxamine (group A, n = 13), deferasirox (group B, n = 11) or deferoxamine with deferiprone (group C, n = 14) and fourteen age- and sex- matched healthy individuals were included in the study. All participants underwent ophthalmoscopy, full-field electroretinography (ERG), visual evoked potentials (VEP), multifocal electroretinography (mfERG), fundus autofluorescence (FAF) imaging and optical coherence tomography (OCT) scans. RESULTS: Retinal pigment epithelium changes were present in two cases. Scotopic ERG demonstrated decreased a-wave amplitude in groups A, B and C (p = 0.03, p = 0.002 and p = 0.002, respectively) and decreased b-wave amplitude in groups B and C (p = 0.002 and p = 0.01, respectively) compared to controls. Photopic ERG showed delayed b-wave latency in groups A and C (p = 0.03 and p = 0.03, respectively) ERG maximal combined response and VEP response did not differ between groups. MfERG showed reduced retinal response density in ring 1 in groups A, B, C (p < 0.001, p < 0.001, p = 0.001, respectively) and ring 2 in group B (p = 0.02) and delayed latency in ring 5 in groups A and B (p = 0.04 and p = 0.04, respectively). Abnormal FAF images appeared in three cases and OCT abnormalities in one case, whereas no changes were observed in controls (p = 0.55 and p = 1.00, respectively). CONCLUSIONS: Full-field ERG and mfERG are more sensitive tools for detecting early retinal changes in ß-thalassemia patients compared with ophthalmoscopy, VEP, FAF imaging and OCT scans.

Pseudoxanthoma elasticum, ocular manifestations, complications and treatment.

Pseudoxanthoma elasticum (PXE), also known as Groenblad syndrome, is an inherited disorder characterised by mineralisation and fragmentation of elastic fibres in a number of organs including the skin, eyes and arterial blood vessels. The clinical manifestations of PXE centre on three major organ systems: skin, cardiovascular system and the eyes. This review focuses on the ocular manifestations of pseudoxanthoma elasticum, namely, peau d'orange, angioid streaks and choroidal neovascularisation, the clinical course of patients, the diagnostic approaches and current therapeutic strategies, such as laser photocoagulation whether transpupillary thermotherapy or photodynamic therapy, macular translocation surgery and anti-vascular endothelial growth factor treatment.