Frequency Doubling Technology for Earlier Detection of Functional Damage in Standard Automated Perimetry-Normal Hemifield in Glaucoma With Low-to-Normal Pressure
Department of Ophthalmology, University of Tokyo Graduate School of Medicine, Tokyo, Japan. Journal of glaucoma
(Impact Factor: 2.11).
05/2011; 21(1):22-6. DOI: 10.1097/IJG.0b013e318202777e
To compare the longitudinal change of frequency doubling technology (FDT) perimetry and standard automated perimetry (SAP) results in SAP-normal hemifield in open-angle glaucoma (OAG) eyes with low-to-normal intraocular pressure (IOP).
FDT perimetry with the N-30 full threshold protocol and SAP using the Humphrey Field Analyzer with the 30-2 Swedish Interactive Threshold Algorithm-standard protocol were periodically performed for at least 3 years in 39 eyes of 39 OAG patients with low-to-normal IOP and visual field damage confined to only one hemifield. The time courses of the mean of the threshold values of FDT and the mean of total deviations (TDs) in SAP-normal and SAP-abnormal fields were analyzed using a linear mixed model.
The average follow-up was 4.9 years and the average IOP during follow-up was 12.6 mm Hg with or without medication. The aging effect-corrected rate of change in the mean FDT threshold values was significantly negative (P=0.004) in the SAP-normal hemifield, whereas that of mean of TD values by SAP did not significantly differ. In the SAP-abnormal hemifield, the rate of change was significantly negative for both tests (P<0.001). The mean of the slope of the mean TD values in the SAP-abnormal hemifield was significantly more negative than that in the SAP-normal hemifield (P=0.011), whereas that of the mean FDT threshold values showed no significant difference between the 2 hemifields.
FDT is useful for monitoring functional damage in the SAP-normal hemifield in OAG eyes with low-to-normal IOP.
Available from: Julia Lamparter
- " Whereas a large number of studies have been published in the past comparing the first-generation FDT with standard automated perimetry, fewer studies have compared the second generation Matrix-FDT with SAP. The majority of these studies included glaucoma patients, , , , , , ,  whereas only few studies included ocular hypertensive subjects. ,  Persons with ocular hypertension have an increased risk of developing glaucoma during their lifetime. "
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ABSTRACT: To evaluate the relationship and agreement between standard automated perimetry (SAP) and Matrix frequency doubling technology (Matrix-FDT) in subjects with ocular hypertension and healthy control subjects.
Forty-four eyes of 44 ocular hypertensive subjects and 29 eyes of 29 healthy age-matched control subjects were included in this prospective study. All participants underwent complete ophthalmic examination, including slit-lamp biomicroscopy, intraocular pressure measurement, pachymetry, and dilated fundus examination, and showed reliable visual field tests. One randomly selected eye of each participant was examined with SAP (Swedish Interactive Threshold Algorithm [SITA] Standard 24-2 test) and Matrix-FDT (24-2 threshold test), in random order. Correlations between global indices (MD, PSD), regions (2 hemifields, 4 quadrants, 6 sectors) and 52 single field positions were analyzed using Spearman's rank correlation coefficient.
In both groups, mean deviation values of SAP and Matrix-FDT correlated significantly (OHT subjects: r = 0.47, p<0.005; healthy subjects: r = 0.68; p<0.001, respectively). Pattern standard deviation of SAP and Matrix-FDT showed no significant correlation in healthy subjects but correlated significantly in ocular hypertensive subjects (r = 0.45, p<0.005). In healthy subjects, a significant correlation between SAP and Matrix-FDT was shown in the supero-temporal and infero-temporal sectors of the disc (r = 0.40 and r = 0.38, p<0.05, respectively). In OHT subjects, supero-temporal, supero-nasal and nasal sectors correlated significantly (r = 0.49, 0.62 and 0.38, p≤0.01, respectively). The correlation pattern of individual visual field test locations appeared heterogeneous in both groups.
In both, ocular hypertensive and healthy subjects SAP and Matrix-FDT correlate well. In ocular hypertensive subjects, both techniques showed good correlation in the supero-temporal, supero-nasal, and nasal sectors of the disc. Poor agreement was found in the temporal, infero-temporal and infero-nasal disc sectors. This missing correlation might be related to early retinal nerve fiber layer damage in these regions of the disc, recognized by one of the visual field instruments.
Available from: Daniel Meira-Freitas
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ABSTRACT: To evaluate the ability of longitudinal frequency doubling technology (FDT) to predict the development of glaucomatous visual field loss on standard automated perimetry (SAP) in glaucoma suspects.
Prospective, observational cohort study.
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.
Glaucoma suspects had intraocular pressure (IOP) >21 mmHg or an optic disc appearance suspicious of glaucoma. All patients had normal or nonrepeatable abnormal SAP at baseline. Humphrey Matrix FDT (Carl Zeiss Meditec, Inc, Dublin, CA) testing was performed within 6 months of SAP testing. The study end point was the development of 3 consecutive abnormal SAP test results. Joint longitudinal survival models were used to evaluate the ability of rates of FDT pattern standard deviation (PSD) change to predict the development of visual field loss on SAP, adjusting for confounding variables (baseline age, mean IOP, corneal thickness, and follow-up measurements of SAP PSD).
The R(2) 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.
Sixty-three of 587 eyes (11%) developed SAP visual field loss during follow-up. The mean rate of FDT PSD change in eyes that developed SAP visual field loss was 0.07 dB/year versus 0.02 dB/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 0.1 dB higher (95% confidence interval [CI], 1.04-1.18; P = 0.002) and 4.40 per 0.1 dB/year faster (95% CI, 1.08-17.96; P = 0.04), respectively. The longitudinal model performed significantly better than the baseline model with an R(2) of 82% (95% CI, 74-89) versus 11% (95% CI, 2-24), respectively.
Rates of FDT PSD change were highly predictive of the development of SAP visual field loss in glaucoma suspects. This finding suggests that longitudinal FDT evaluation may be useful for risk stratification of patients with suspected glaucoma.
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