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Published on: September 3, 2020
ELECTRORETINOGRAPHIC AND VISUAL-EVOKED POTENTIAL CHANGES IN RELATION TO CHELATION MODALITY IN CHILDREN WITH
Amany Abd El-Shazly1, Weam Mohamed Ebeid, Rania Serag Elkitkat
1Departments of *Ophthalmology and †Pediatrics, Faculty of Medicine, Ain Shams University, Cairo, Egypt.
Insights
Electrophysiological studies reveal preclinical retinal changes in children with thalassemia, particularly those on deferoxamine chelation. Multifocal electroretinogram and pattern electroretinogram can detect early macular toxicity.
Area of Science:
- Ophthalmology
- Hematology
- Neuroscience
Background:
- Thalassemia is a genetic blood disorder requiring lifelong iron chelation therapy.
- Iron overload from transfusions can lead to organ damage, including the eyes.
- Early detection of ocular complications is crucial for managing thalassemia patients.
Purpose of the Study:
- To assess electrophysiological methods for detecting retinal and visual pathway changes in children with thalassemia.
- To correlate these changes with different iron chelation modalities.
- To investigate potential early toxic effects of chelation therapy on the macula and optic nerve.
Main Methods:
- A study involving 60 patients on deferasirox (Group 1), 60 on deferoxamine (Group 2), and 60 controls (Group 3).
- Comprehensive ophthalmologic examinations were performed.
- Electrophysiological tests included pattern visual-evoked potential (PVEP), pattern electroretinogram (PERG), and multifocal electroretinogram (mfERG).
Main Results:
- No fundus abnormalities were observed in any group.
- mfERG showed significantly lower P1 amplitudes in both chelation groups compared to controls, with Group 2 having lower amplitudes than Group 1.
- PERG revealed significant differences in P50 wave latency and N35-P50 amplitude between groups (P < 0.001).
- PVEP and N95 wave of PERG showed no significant differences.
- Chelation modality was the primary determinant for mfERG and P50 parameters.
Conclusions:
- Electrophysiological studies indicate preclinical retinal changes in thalassemic patients, more pronounced with deferoxamine.
- Findings suggest early macular toxicity rather than optic nerve damage.
- Regular follow-up with mfERG and PERG is recommended for monitoring ocular health in thalassemic children.
Purpose:
To evaluate possible benefits of using electrophysiological investigations for detecting retinal and visual pathway changes and correlating them with chelation modality in children with thalassemia.
Methods:
This study included 60 patients on single oral iron chelator (deferasirox) (Group 1), 60 on deferoxamine chelator (Group 2), and 60 controls (Group 3). Participants underwent full ophthalmologic examination, pattern visual-evoked potential, pattern electroretinogram, and multifocal electroretinogram.
Results:
Fundus showed no abnormalities. Multifocal electroretinogram mean P1 amplitude showed statistically significant differences in all 5 rings, amplitudes being significantly lower in Groups 1 and 2 than Group 3; moreover, significantly lower in Group 2 than Group 1. There was a statistically significant difference between groups regarding P50 wave latency and N35-P50 of pattern electroretinogram amplitude (P < 0.001 and P < 0.001, respectively). However, there were no statistically significant differences between groups regarding N95 wave of pattern electroretinogram and pattern visual-evoked potential waves' amplitude and latency. Multiple regression analyses illustrated that chelator was the most important determinant for multifocal electroretinogram and P50 parameters.
Conclusion:
Preclinical electrophysiologic changes existed in thalassemics, more obvious in those on deferoxamine. Electrophysiologic studies analysis denotes an early toxic macular insult rather than optic nerve affection. Thus, regular follow-up using multifocal electroretinogram and pattern electroretinogram is recommended.
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