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Objective Derivation of the Morphology and Staging of Visual Field Loss Associated with Long-Term Vigabatrin Therapy.
CNS Drugs 2019; 33(8):817-829CD

Abstract

BACKGROUND

The morphology and between-eye symmetry of the visual field loss associated with the antiepileptic drug vigabatrin (VAVFL) has received little attention.

OBJECTIVE

Our objective was to model the appearance and ensuing staging of VAVFL derived with the European Medicines Agency-approved perimetric protocol.

METHODS

This was a retrospective, cross-sectional, observational study that identified 123 adults who had received vigabatrin for refractory seizures and who had no evidence of co-existing retino-geniculo-cortical visual pathway abnormality. A further 38 adults with refractory seizures and identical inclusion criteria but no exposure to vigabatrin acted as controls. For each group, the median outcome at each stimulus location in each eye (of absolute loss, relative loss or Pattern Deviation probability level, as appropriate) was derived for each successive ten pairs of fields, ranked for severity. Between-eye symmetry was quantified by an index that accounted for severity of loss and that was referenced to the likelihood of the occurrence of symmetry due to chance.

RESULTS

The modelled VAVFL was bilateral and highly symmetrical and was described by six stages that were all independent of the extent of vigabatrin exposure. The loss originated in the extreme temporal periphery and encroached centripetally along all meridians towards fixation. The initial appearance within the central field (Stage 2) occurred inferior-nasally. Subsequent stages exhibited increasing loss, which was greater nasally than temporally. Stage 6 described concentric loss extending to approximately 15° eccentricity from fixation.

CONCLUSION

The model exhibited a consistent pattern of VAVFL. The staging of the loss could assist the risk:benefit analysis of vigabatrin for the treatment of epilepsy.

Authors+Show Affiliations

College of Biomedical Sciences, Cardiff University, Maindy Road, Cardiff, CF24 4HQ, UK. wildjm@cardiff.ac.uk.Alan Richens Unit, Welsh Epilepsy Centre, University Hospital of Wales, Heath Park, Cardiff, CF14 4XW, UK.College of Biomedical Sciences, Cardiff University, Maindy Road, Cardiff, CF24 4HQ, UK.

Pub Type(s)

Journal Article

Language

eng

PubMed ID

31250314

Citation

Wild, John M., et al. "Objective Derivation of the Morphology and Staging of Visual Field Loss Associated With Long-Term Vigabatrin Therapy." CNS Drugs, vol. 33, no. 8, 2019, pp. 817-829.
Wild JM, Smith PEM, Knupp C. Objective Derivation of the Morphology and Staging of Visual Field Loss Associated with Long-Term Vigabatrin Therapy. CNS Drugs. 2019;33(8):817-829.
Wild, J. M., Smith, P. E. M., & Knupp, C. (2019). Objective Derivation of the Morphology and Staging of Visual Field Loss Associated with Long-Term Vigabatrin Therapy. CNS Drugs, 33(8), pp. 817-829. doi:10.1007/s40263-019-00634-2.
Wild JM, Smith PEM, Knupp C. Objective Derivation of the Morphology and Staging of Visual Field Loss Associated With Long-Term Vigabatrin Therapy. CNS Drugs. 2019;33(8):817-829. PubMed PMID: 31250314.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Objective Derivation of the Morphology and Staging of Visual Field Loss Associated with Long-Term Vigabatrin Therapy. AU - Wild,John M, AU - Smith,Philip E M, AU - Knupp,Carlo, PY - 2019/6/30/pubmed PY - 2019/6/30/medline PY - 2019/6/29/entrez SP - 817 EP - 829 JF - CNS drugs JO - CNS Drugs VL - 33 IS - 8 N2 - BACKGROUND: The morphology and between-eye symmetry of the visual field loss associated with the antiepileptic drug vigabatrin (VAVFL) has received little attention. OBJECTIVE: Our objective was to model the appearance and ensuing staging of VAVFL derived with the European Medicines Agency-approved perimetric protocol. METHODS: This was a retrospective, cross-sectional, observational study that identified 123 adults who had received vigabatrin for refractory seizures and who had no evidence of co-existing retino-geniculo-cortical visual pathway abnormality. A further 38 adults with refractory seizures and identical inclusion criteria but no exposure to vigabatrin acted as controls. For each group, the median outcome at each stimulus location in each eye (of absolute loss, relative loss or Pattern Deviation probability level, as appropriate) was derived for each successive ten pairs of fields, ranked for severity. Between-eye symmetry was quantified by an index that accounted for severity of loss and that was referenced to the likelihood of the occurrence of symmetry due to chance. RESULTS: The modelled VAVFL was bilateral and highly symmetrical and was described by six stages that were all independent of the extent of vigabatrin exposure. The loss originated in the extreme temporal periphery and encroached centripetally along all meridians towards fixation. The initial appearance within the central field (Stage 2) occurred inferior-nasally. Subsequent stages exhibited increasing loss, which was greater nasally than temporally. Stage 6 described concentric loss extending to approximately 15° eccentricity from fixation. CONCLUSION: The model exhibited a consistent pattern of VAVFL. The staging of the loss could assist the risk:benefit analysis of vigabatrin for the treatment of epilepsy. SN - 1179-1934 UR - https://www.unboundmedicine.com/medline/citation/31250314/Objective_Derivation_of_the_Morphology_and_Staging_of_Visual_Field_Loss_Associated_with_Long-Term_Vigabatrin_Therapy L2 - https://dx.doi.org/10.1007/s40263-019-00634-2 DB - PRIME DP - Unbound Medicine ER -