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

Dettoraki, Maria; Kattamis, Antonis; Ladas, Ioannis; Maragkos, Konstantinos; Koutsandrea, Chryssanthi; Chatzistefanou, Klio; Laios, Konstantinos; Brοuzas, Dimitrios; Moschos, Marilita M.

doi:10.1007/s00417-017-3650-9

Cited by 10 publications

(11 citation statements)

References 27 publications

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“…Accordingly, chelation therapy was excluded from among possible causes. Nonetheless, a recent study, 50 published after completion of our study, reported that some beta-thalassemic patients receiving chelating therapy, without presenting any visible defects, showed electroretinogram alterations. A potential future area of focus for further study should consider this examination as a possible tool for identifying early alterations, even in asymptomatic patients.…”

Section: Discussionmentioning

confidence: 65%

Long-Term Effects of Iron Chelating Agents on Ocular Function in Patients with Thalassemia Major

Nuzzi¹,

Geronazzo²,

Tridico³

et al. 2021

OPTH

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Background:The aim of this study is to evaluate eye structures and function in patients receiving iron chelating therapy and to assess whether a correlation exists between the onset of ocular alterations and the intake of iron chelating drugs. Methods: A prospective cohort study was performed. Eighty-eight patients, composed of children and adults with thalassemia major (TM) who are taking or had taken iron chelating drugs (deferoxamine, deferiprone or deferasirox), have been initially enrolled in the study. The final sample featured 80 patients, including 18 children and 62 adults. These subjects received an eye examination to evaluate intraocular pressure (IOP), best corrected visual acuity (BCVA), the presence of refractive defects, cornea, anterior chamber, lens, fundus oculi, visual field and mean retinal nerve fiber layer (RNFL) thickness. Logistic regression model analysis was performed in order to assess any correlation. In addition, a literature search regarding the relation between iron chelating drugs and ocular adverse events was carried out to compare the results obtained with the evidence in the literature. Results: Logistic regression did not report a significant correlation between the intake of iron chelating drugs and the onset of anterior ocular segment alterations, lens opacities, retinal diseases, optical neuropathies, astigmatism, visual field and RNFL thickness defects. Logistic regression returned a statistically significant correlation between myopia and iron chelation therapy (p-value 0.04; OR 1.05) and also between presbyopia and total duration of therapy with deferoxamine (p-value 0.03; OR 1.21). Although intraocular pressure levels remained within the normal range, a significant correlation with the length of deferoxamine therapy has been found (p-value 0.002; association coefficient −0.12). A negative correlation between deferiprone and presbyopia has also been observed. Conclusion: Iron chelation therapy is not associated with severe visual function alterations. Limitation of deferoxamine treatment can help prevent ocular complications. Deferiprone and/or deferasirox may be preferable, especially in patients over age 40 years.

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Section: Discussionmentioning

confidence: 65%

Long-Term Effects of Iron Chelating Agents on Ocular Function in Patients with Thalassemia Major

Nuzzi¹,

Geronazzo²,

Tridico³

et al. 2021

OPTH

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“…There are studies showing that it may be toxic to the eye although it's side effects are less compared to Deferoxamine. In a recent study, ERG and mfERG responses were reduced in thalassemic patients regardless of the type of chelation therapy they received [17]. On the contrary Sakamoto et al suggested that iron-chelating agents was protected retinal neurons against excitoneurotoxicity via reduction of iron content and oxidative stress in the rats [18].…”

Section: Discussionmentioning

confidence: 92%

Ganglion cell complex analysis in thalassemia major patients measured by optical coherence tomography

Koca

Yakarisik

2021

Health Sci. Q.

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To analyze the changes in ganglion cell complex (GCC), peripapillary retinal nerve fiber layer (RNFL) thickness and central macular thickness (CMT) on spectral domain optical coherence tomography (OCT) in patients with thalassemia major. Forty one eyes of 41 patients with thalassemia major and 41 eyes of 41 healthy subjects were included in this prospective and comparative study. Peripapillary RNFL thickness, CMT and macular GCC thickness were evaluated with OCT (Cirrus HD-OCT 5000Carl Zeiss Meditec, Inc, Dublin, CA, USA) in all patients and healthy controls. Additionally, disease duration, serum ferritin level, hemoglobin concentration, the dosage and duration of chelation therapy, count of transfusion, patient’s weight were analyzed in thalassemia major group. RNFL thickness values were lower in the thalassemia patients but the difference was not statistically significant (except superior quadrant) and there was no significant differences in the mean CMT measurements. GCC thickness was thinner in all areas ( average, superior, inferior, superior-temporal, inferior-temporal, superior-nasal, inferior-nasal) but only the thinning in the inferior-temporal was statistically significant. GCC and RNFL thickness changes occur earlier than CMT changes in β-thalassemia major patients. GCC thickness measurements can be used for follow-up in combination with other diagnostic methods.

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“…Electroretinogram and electrooculogram (EOG) are usually confirmatory of DFO retinopathy and appear to be more sensitive in detecting early retinal damage than fundoscopy alone [ 3 ]. A recent study suggests that ffERG and multi-focal ERG are more sensitive in early damage detection than visual evoked potential, FAF imaging and OCT scans in patients under chelation therapy [ 32 ]. For instance, there are reports of bilateral reductions in response densities at the central retina corresponding to RPE changes related to DFO toxicity [ 3 , 33 , 34 ].…”

Section: Discussionmentioning

confidence: 99%

Pattern dystrophies in patients treated with deferoxamine: report of two cases and review of the literature

et al. 2018

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BackgroundDeferoxamine (DFO) is one of the most commonly used chelation treatments for transfusional hemosiderosis. Pattern dystrophies constitute a distinct entity of retinal disorders that has been occasionally identified in association with deferoxamine.Case presentationWe report two cases of bilateral macular pattern dystrophy in transfusion dependent patients undergoing chronic chelation therapy with deferoxamine due to thalassemias. Our patients were evaluated with multimodal imaging and the results are presented. Both patients had normal cone and rod responses in the full-field electroretinogram and continued the prescribed chelation therapy, after hematology consult. The patients were followed up every 3 months for 2 and 4 years respectively for possible deterioration. Their best corrected visual acuity remained stable with no anatomic change on Optical Coherence Tomography findings.ConclusionMultimodal imaging of our patients allowed a better evaluation and possibly earlier detection of the DFO-related changes. Screening and close follow up of patients under chronic chelating therapy is important in order to promptly diagnose and manage possible toxicity either with discontinuation of the offending agent or dose modification.

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

Abstract: Full-field ERG and mfERG are more sensitive tools for detecting early retinal changes in β-thalassemia patients compared with ophthalmoscopy, VEP, FAF imaging and OCT scans.

Cited by 10 publications

References 27 publications

Long-Term Effects of Iron Chelating Agents on Ocular Function in Patients with Thalassemia Major

Long-Term Effects of Iron Chelating Agents on Ocular Function in Patients with Thalassemia Major

Ganglion cell complex analysis in thalassemia major patients measured by optical coherence tomography

Pattern dystrophies in patients treated with deferoxamine: report of two cases and review of the literature

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