Review of the Use of SWAP and FDT for the Early Detection of Visual Field Loss

Abstract

Background: To review the literature reporting SWAP and FDT for the early detection of visual field loss in glaucoma. Methods: A review of literature published on Medline, Scopus and Web of Science between 1966 and present was undertaken with only articles in the English language reviewed. Results: SWAP has high inter and intra subject variability. There is no uniform decision as to what criteria should be applied to define abnormal visual fields. In comparison with standard automated perimetry (SAP) there is controversy as to whether SWAP is reliable in detecting glaucomatous damage. As a screening tool FDT may have potential due to its short testing time and lower test-retest variability. There is a lack of definitive abnormality criteria to define visual field loss with FDT. First and second generation FDT have been found to be comparable to SWAP in terms of diagnostic sensitivity. There is a lack of studies comparing FDT to SAP with longitudinal follow up of visual fields which make it difficult to determine its reliability in identifying pre-perimetric glaucomatous damage. Conclusion: There is a need for further longitudinal studies on both SWAP and FDT to determine fully their reliability in detecting early visual field loss in glaucoma before SAP.