Frequency doubling technology, optical coherence technology and pattern electroretinogram in ocular hypertension

Frequency doubling technology, optical coherence technology and pattern electroretinogram in ocular hypertension: an observational study

Status

Active, not recruiting

Phases

Unknown

Study type

Observational

Source

ISRCTN

Registry ID

ISRCTN70295497

Enrollment

107

Registered

2011-07-06

Start date

2010-01-01

Completion date

Unknown

Last updated

2017-05-08

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Ocular hypertension Eye Diseases Ocular hypertension

Interventions

All patients underwent: 1. An ophthalmologic examination including visual acuity and applanation IOP assessment 2. Ccorneal radius curvature measurement with automated keratometry (RK, Canon Inc., T

Eligibility

Sex/Gender

All

Inclusion criteria

Inclusion criteria: 1. 52 patients aged between 44 and 76 years (mean 56±9.6), with an intraocular pressure (IOP) greater than 21 mmHg (mean 23.96±1.3) 2. A control group consisted of 55 subjects aged between 42 and 75 years (mean 54.8±10.4)

Exclusion criteria

Exclusion criteria: 1. Previous history of eye surgery 2. Previous history of ocular inflammation 3. Previous hystory of systemic diseases

Design outcomes

Primary

Measure	Time frame
1. The latest generation OCT3 (Zeiss-Humphrey, Dublin, CA) was used to assess and measure the thickness of the peripapillary retinal fiber layer 2. Using the RNFL Thickness Average program, which performs three consecutive, circular scans, each one 3.4 mm in diameter centred around the optic nerve 3. The thickness of the fibers was defined as the number of pixels obtained between the anterior and posterior RNFL projection 4. The values obtained with each scan are shown in graphic form, resembling a clock face divided into four quadrants, representing the superior, nasal, inferior and temporal sections of the RNFL expressed in microns 5. Frequency-doubling technology (FDT) perimetry is a new technique designed for the rapid and effective identification of visual field impairment due to glaucoma. The FDT stimulus consists of a bar grid with a low frequency spatial sinusoidal profile (0.25 cycles/degree) subjected to a sinusoidal temporal commutation at a frequency of 25 Hz. For each visual field we evaluated the mean defect (MD) and the pattern standard deviation (PSD). 6. For PERG recording we followed ISCEV standard guideline. The PERG stimulus was a black and white checherboard of 1.6 cycles/degree with a contrast of 99%, four reversal/s and a mean luminance of 110 cd/m2. The transient PERG response was characterized by three subsequent peaks that in normal subjects are indicated on the basis of polarity and latency: N35, P50 and N95. 7. All statistical analyses were performed using the FASTAT Version 2 program package (Systat Inc., Evanston, Illinois) using the Student t test for unpaired data and Bonferroni correction, assuming p < 0.01 as significant 8. The Chi-square test was used for categorical data 9. The Bartlett correlation test was used to assess any correlation between thinning of the RNFL and alterations in the FDT indexes with IOP and the hemodynamic indices 10. Finally, Receiver Operating Characteristic (ROC) curve analysis was performed to determin	—

Measure

Time frame

1. The latest generation OCT3 (Zeiss-Humphrey, Dublin, CA) was used to assess and measure the thickness of the peripapillary retinal fiber layer 2. Using the RNFL Thickness Average program, which performs three consecutive, circular scans, each one 3.4 mm in diameter centred around the optic nerve 3. The thickness of the fibers was defined as the number of pixels obtained between the anterior and posterior RNFL projection 4. The values obtained with each scan are shown in graphic form, resembling a clock face divided into four quadrants, representing the superior, nasal, inferior and temporal sections of the RNFL expressed in microns 5. Frequency-doubling technology (FDT) perimetry is a new technique designed for the rapid and effective identification of visual field impairment due to glaucoma. The FDT stimulus consists of a bar grid with a low frequency spatial sinusoidal profile (0.25 cycles/degree) subjected to a sinusoidal temporal commutation at a frequency of 25 Hz. For each visual field we evaluated the mean defect (MD) and the pattern standard deviation (PSD). 6. For PERG recording we followed ISCEV standard guideline. The PERG stimulus was a black and white checherboard of 1.6 cycles/degree with a contrast of 99%, four reversal/s and a mean luminance of 110 cd/m2. The transient PERG response was characterized by three subsequent peaks that in normal subjects are indicated on the basis of polarity and latency: N35, P50 and N95. 7. All statistical analyses were performed using the FASTAT Version 2 program package (Systat Inc., Evanston, Illinois) using the Student t test for unpaired data and Bonferroni correction, assuming p < 0.01 as significant 8. The Chi-square test was used for categorical data 9. The Bartlett correlation test was used to assess any correlation between thinning of the RNFL and alterations in the FDT indexes with IOP and the hemodynamic indices 10. Finally, Receiver Operating Characteristic (ROC) curve analysis was performed to determin

—

Secondary

Measure	Time frame
Data of OCT, FDT and PERG of ocular hypertensive patients were compared to healthy controls	—

Countries

Italy

Outcome results

None listed

Source: ISRCTN (via WHO ICTRP) · Data processed: Mar 25, 2026