Clinical comparison of frequency doubling technology perimetry and Humphrey perimetry

Abstract

Aim-To determine the number of missed points on frequency doubling technology (FDT) perimetry that optimise the sensitivity and specificity of the test and to determine the topographical accuracy of the test in a clinical setting. Methods-In a prospective study, the perimetric data from 99 patients who underwent both FDT perimetry in the screening mode and Humphrey 24-2 (H24-2) were used to determine the sensitivity and specificity of the FDT perimetry compared with the full threshold H24-2 as the gold standard. Results-Missed points on the FDT perimetry correlated with both the mean deviation and the corrected pattern standard deviation on the Humphrey perimetry. A score assigned to abnormal points on the FDT perimetry and the Humphrey total deviation plot showed a significant correlation for both the location and the depth of the defect. In comparing the Humphrey hemifield test with the FDT perimetry results, if at least one missed point on the frequency doubling test was considered as abnormal then the overall sensitivity of the test was 78.1% and the specificity was 89.1%. Conclusion-FDT perimetry in the screening mode performed in a clinical setting was highly specific, exhibited reasonable sensitivity, and accurately determined the location and depth of scotomas when compared with the full threshold Humphrey 24-2. (Br J Ophthalmol 2001;85:360-362) Frequency doubling technology is a relatively new method of visual field testing that relies on an optical illusion first described by Kelly in 1966.1 The anatomical substrate of this eVect has been ascribed to the retinal ganglion cells (RGCs), 2 which are thought to be particularly susceptible to early glaucomatous damage. This has led to the development of frequency doubling technology (FDT) perimetry with particular use as a glaucoma screening tool. 5-7Preliminary results suggest that FDT perimetry is a rapid, valid test for glaucomatous field loss. 8-16In a clinical study of glaucoma suspects, Quigley 8 found a sensitivity and specificity of over 90% compared with Humphrey full threshold perimetry. Other investigators have recently corroborated the high specificity but have reported a lower sensitivity. 14-16Although preliminary results are impressive, the optimal interpretation of FDT perimetry data is unclear. Further clinical data are needed before this test can be confidently and accurately applied in clinical practice. Furthermore, there are limited data on the topographical accuracy of FDT perimetry.We conducted a prospective clinic based study comparing FDT perimetry with Humphrey 24-2 (H24-2) perimetry in a consecutive series of patients who were attending our glaucoma clinic. We determined the number of missed points on the FDT perimetry that optimised the sensitivity and specificity of the test in screening mode and determined the ability of FDT perimetry to localise the location and depth of a scotoma. MethodsAll patients involved in the study were attending the glaucoma service at the Stoke Mandeville eye unit, as either a review or a ...

Frequency doubling technique perimetry and spectral domain optical coherence tomography in patients with early glaucoma

“…1,[7][8][9] In recent years, new sensory tests, as well as morphological techniques, have been developed to detect glaucomatous defects at an early stage. It has been shown, that quantitative measurements of the retinal nerve fibre layer 10 and perimetry using frequency-doubling technique (FDT) 11,12 may be helpful in glaucoma diagnosis.…”

Evaluation of the high specificity Screening Program (C-20-1) of the Frequency Doubling Technology (FDT) perimeter in clinical practice

“…2,12,22,29,30 Quigley 2 reported a sensitivity of 91% and a specificity of 94% using a criterion of two or more stimulus locations exhibiting abnormality for Program C-20-1 compared to the HFA Full Threshold algorithm and Program 24-2 with abnormality designated in terms of the Glaucoma Hemifield Test. The specificity with Program C-20-1 in the current study was similar (93%) to that of Quigley, 2 but the sensitivity was lower (68%) compared to the outcome with Program 24-2 when the identical criterion for abnormality was used.…”

“…The Screening Program C-20-1 of the FDT has been evaluated with respect to Programs 24-2 or 30-2 and either the SITA Standard or Full Threshold algorithms of the HFA. 11,12,[27][28][29][30] The HFA SITA Fast algorithm in conjunction with Program 24-2 is gaining popularity in some glaucoma clinics due to its shorter examination time compared to that with the HFA SITA Standard algorithm, which, for patients with glaucoma, takes approximately 6-8 min per eye for Program 30-2. [31][32][33][34] The SITA Fast algorithm and Program 24-2 typically takes 4-5 min per eye in patients with glaucoma 35 while the C-20-1 screening program of the FDT takes in the region 1-2 min per eye.…”

“…[31][32][33][34] The SITA Fast algorithm and Program 24-2 typically takes 4-5 min per eye in patients with glaucoma 35 while the C-20-1 screening program of the FDT takes in the region 1-2 min per eye. 11,22,30,35 To our knowledge, only two studies have compared the FDT suprathreshold Program C-20-1 with HFA Program 24-2 and the SITA Fast algorithm. 22,35 Allen et al 35 evaluated these two techniques in a systematic screening program of 574 attendees to a convention.…”

Sensibilidade do estímulo de tamanho I na perimetria computadorizada acromática para a detecção de defeitos glaucomatosos no campo visual: análise comparativa com as perimetrias de ondas curtas e acromática convencional (SITA)

“…O FDT revelou-se altamente sensível e específico no diagnóstico do glaucoma, sendo capaz de detectar defeitos perimétricos antes da perimetria convencional (5) . Também mostrou ser mais sensível que a polarimetria de varredura a laser e fotografias da camada de fibras nervosas da retina (6) .…”