Predicting Progression of Glaucoma from Rates of Frequency Doubling Technology Perimetry Change

Abstract

Purpose To evaluate the ability of longitudinal frequency doubling technology (FDT) to predict development of glaucomatous visual field loss on standard automated perimetry (SAP) in glaucoma suspects. Design Prospective observational cohort study. Participants The study included 587 eyes of 367 patients with suspected glaucoma at baseline selected from the Diagnostic Innovations in Glaucoma Study (DIGS) and the African Descent and Glaucoma Evaluation Study (ADAGES). These eyes had an average of 6.7±1.9 FDT tests during a mean follow-up time of 73.1±28.0 months. Methods Glaucoma suspects had either intraocular pressure >21mmHg or an optic disc appearance suspicious of glaucoma. All patients had either normal or non-repeatable abnormal SAP at baseline. Humphrey Matrix FDT testing was performed within 6 months of SAP testing. The study endpoint was the development of 3 consecutive abnormal SAP tests. Joint longitudinal survival models were used to evaluate the ability of rates of FDT pattern standard deviation (PSD) change to predict development of visual field loss on SAP, adjusting for confounding variables (baseline age, mean intraocular pressure, corneal thickness, and follow-up measurements of SAP PSD). Main Outcome Measures The R2 index was used to evaluate and compare the predictive abilities of the model containing longitudinal FDT PSD data with the model containing only baseline data. Results Sixty-three of 587 (11%) eyes developed SAP visual field loss during follow-up. The mean rate of FDT PSD change in eyes that developed SAP visual field loss was 0.07dB/year versus 0.02dB/year in those that did not (P<0.001). Baseline FDT PSD and slopes of FDT PSD change were significantly predictive of progression, with hazard ratios of 1.11 per 0.1dB higher (95% confidence interval [CI]: 1.04 - 1.18; P=0.002) and 4.40 per 0.1dB/year faster (95%CI: 1.08 - 17.96; P=0.04), respectively. The longitudinal model performed significantly better than the baseline model with R2 of 82% (95%CI: 74% - 89%) vs. 11% (95%CI: 2% - 24%), respectively. Conclusion Rates of FDT PSD change were highly predictive of development of SAP visual field loss in glaucoma suspects. This finding suggests that longitudinal FDT evaluation may be useful for risk stratification of patients suspected of having glaucoma.

How to detect progression in glaucoma

“…In glaucoma suspects, Meira-Freitas et al (2014) reported that faster rates of increase of FDT pattern deviation were related to higher chance of progression in SAP, and Liu et al (2014b) reported that approximately the same number of suspects developed reproducible defects in FDT or in SAP. In glaucoma patients, Liu et al (2014a) identified more progressing patients with FDT than SAP; however, Redmond et al (2013) identified more progressing patients with SAP than FDT.…”

Frequency Doubling Technology Perimetry and Changes in Quality of Life of Glaucoma Patients: A Longitudinal Study

“…7–9 Recent studies have also suggested that FDT perimetry may detect progressive visual field defects not apparent on SAP. 10 …”

Strategies to improve early diagnosis in glaucoma

“…FDT perimetry, which determines the contrast sensitivity for detecting a high temporal frequency counter-phase flicker stimulus, was designed to selectively evaluate the M pathway; however, there is now evidence that the response to motion perimetry is in fact generated by many ganglion cell types and is cortically mediated (White et al, 2002). Nevertheless, FDT has shown promise for glaucoma detection (Cello et al, 2000;Horn et al, 2002;Johnson and Samuels, 1997;Medeiros et al, 2004aMedeiros et al, , 2006Quigley, 1998) and longitudinal studies have shown that abnormalities on FDT can precede detectable SAP changes by several years (Landers et al, 2003;Meira-Freitas et al, 2014).…”