Evaluation of the effectiveness of frequency doubling technology perimetry in the diagnosis of optic neuropathies

Abstract

PURPOSE. To compare the diagnostic effectiveness of two perimetric threshold strategies with frequency-doubling technology in patients with early primary open-angle glaucoma (POAG), the optical form of multiple sclerosis (MS) and papilledema in an open-label comparative clinical study.MATERIAL AND METHODS. The study involved 78 patients (105 eyes) with optic neuropathies (ON). The patients were divided into 3 groups depending on the etiology of optic neuropathy: the first group included 30 patients (46 eyes) with early POAG aged 30 to 65 years (54.9±1.3); the second group included 26 patients (26 eyes) diagnosed with the optic form of MS (an episode of retrobulbar optic neuritis in the medical history) aged 22 to 44 years (33.7±6.5); the third group consisted of 22 patients (33 eyes) aged from 18 to 66 years (35.7±14.9) with papilledema caused in the majority of cases by various brain tumors (25 eyes or 75.7%). The fourth (control) group consisted of 60 healthy individuals (60 eyes) aged 20 to 65 years, who were divided into 2 equal subgroups – younger (24.8±4.4) and older (56.4±3.9).Standard and non-standard perimetry was performed on all subjects during a comprehensive ophthalmic examination using the Humphrey 745i Visual Field Analyzer II (HFA II, «24-2» threshold strategy) (Germany-USA) and the author's own modification of Frequency Doubling Technology (FDT) Perimetry, in the form of 2 threshold strategies: the well-known «FDT-16» and the new «FDT-64».RESULTS. Both the «FDT-16» and the «FDT-64» threshold strategies were more effective in diagnosing glaucomatous optic neuropathy (GON), as confirmed by the higher sensitivity of their results to two criteria — the number of identified scotomas (n of scotomas n≥2), and the number of scotoma clusters in patients with POAG (88 and 100%; 95 and 83%, respectively) compared with those in patients with MS (61 and 76%; 85 and 54%, respectively) and papilledema (51 and 78%; 88 and 70%, respectively). The specificity of the «FDT-16» and «FDT-64» threshold strategies was significantly higher than the specificity of Humphrey perimetry (100, 80 and 63%, respectively).CONCLUSION. Both perimetric threshold strategies with frequency-doubling technology were found to be the most effective in detecting GON. This confirms that they are more sensitive in patients with early POAG when compared with the sensitivity in patients with MS and papilledema. The level of specificity of both FDT perimetry strategies far exceeds the level of specificity of Humphrey perimetry data, which indicates the advantage of FDT perimetry in separating healthy people from patients with ON, and not only of glaucoma genesis.