Condition category
Eye Diseases
Date applied
29/06/2011
Date assigned
06/07/2011
Last edited
30/10/2012
Prospective/Retrospective
Retrospectively registered
Overall trial status
Completed
Recruitment status
No longer recruiting

Plain English Summary

Lay summary under review 3

Trial website

Contact information

Type

Scientific

Primary contact

Dr Mauro Cellini

ORCID ID

Contact details

Via Dagnini 28
Bologna
40137
Italy
mauro.cellini@unibo.it

Additional identifiers

EudraCT number

ClinicalTrials.gov number

Protocol/serial number

FDT OH-06-10

Study information

Scientific title

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

Acronym

Study hypothesis

Glaucoma is an optic neuropathy with the progressive loss of ganglion cells and consequent visual field alterations. The appearance of alterations in the retinal nerve fiber layer represents an early sign of glaucoma damage that precedes the changes in the optic nerve and peripheral alterations.

The quantitative investigation techniques used for the study of the retinal nerve fiber layer (RNFL) are Scanning Laser Polarimetry (SLP), Heidelberg Retinal Tomography (HRT) and, more recently, Optical Coherence Tomography (OCT). OCT makes it possible to examine high resolution cross-sections of ocular tissues using the low coherence interferometry principle and seems more reliable than SLP and HRT in the study of the RNFL.

Due to irreversible nature of the retinal ganglion cell loss and axonal damage, it is particularly important to use high quality investigation techniques for study of glaucoma patients to facilitate early detection of functional deterioration. The qualitative analysis methods currently available are Standard Achromatic Perimetry (SAP) and the more sensitive Short Wavelength Automated Perimetry (SWAP) as well as the recent Frequency-Doubling Technology (FDT) perimetry. The Pattern Electroretinogram (PERG) was introduced 25 years ago to discriminate between healthy and glaucomatous eyes as it records the electrical potentials of retinal ganglion cells and ganglion cell damage is the main cause of the decrease in visual sensitivity in glaucomatous eyes.

Study aim:
To assess which of three methods (Optical Coherence Tomography (OCT), Pattern Electroretinogram (PERG) and Frequency-Doubling Technology (FDT) is the most sensitive and specific for detecting early glaucomatous damage in ocular hypertension (OH).

Ethics approval

Local Ethics Committee of the S. Orsola-Malpighi Hospital, Bologna 26/06/2011 ref: FDT OH-06-10

Study design

Retrospective observational study

Primary study design

Observational

Secondary study design

Randomised controlled trial

Trial setting

Hospitals

Trial type

Diagnostic

Patient information sheet

Not available in web format, please use the contact details below to request a patient information sheet

Condition

Ocular hypertension

Intervention

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., Tokyo, Japan)
3. Corneal thickness evaluation with a Tomey SP3000 pachymeter (Tomey Corp., Nagoya, Japan)
4. Biomicroscopy of the anterior and posterior segment with automatic measurement of the C/D area ratio of the optic nerve head with OCT3 (Zeiss-Humphrey, Dublin, CA).
5. Standard achromatic perimetry was also performed (SAP) with a Humphrey Field Analyzer-30.2 full threshold program (Zeiss-Humphrey, Dublin, CA)
6. Assessment of the RFNL with OCT3 (Zeiss-Humphrey, Dublin, CA)
7. Frequency-doubling technology (FDT) perimetry with RFA (Zeiss-Humphrey, Dublin, CA) 8. Pattern electrinogram (PERG) with an EREV2000 system (LACE Instruments, Pisa, Italy)

Intervention type

Other

Phase

Not Applicable

Drug names

Primary outcome measures

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 determine the diagnostic sensitivity and specificity of OCT, FDT and PERG

Secondary outcome measures

Data of OCT, FDT and PERG of ocular hypertensive patients were compared to healthy controls

Overall trial start date

01/01/2010

Overall trial end date

01/11/2010

Reason abandoned

Eligibility

Participant 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)

Participant type

Patient

Age group

Adult

Gender

Both

Target number of participants

52 patients and 55 controls healthy subjects

Participant exclusion criteria

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

Recruitment start date

01/01/2010

Recruitment end date

01/11/2010

Locations

Countries of recruitment

Italy

Trial participating centre

Via Dagnini 28
Bologna
40137
Italy

Sponsor information

Organisation

University of Bologna (Italy)

Sponsor details

Via Palagi
9
Bologna
40138
Italy
+39 (0)51 34 14 50
mauro.cellini@unibo.it

Sponsor type

University/education

Website

Funders

Funder type

University/education

Funder name

University of Bologna (Italy)

Alternative name(s)

Funding Body Type

Funding Body Subtype

Location

Results and Publications

Publication and dissemination plan

Not provided at time of registration

Intention to publish date

Participant level data

Not provided at time of registration

Results - basic reporting

Publication summary

1. 2012 results in http://www.ncbi.nlm.nih.gov/pubmed/22853436

Publication citations

  1. Results

    Cellini M, Toschi PG, Strobbe E, Balducci N, Campos EC, Frequency doubling technology, optical coherence technology and pattern electroretinogram in ocular hypertension., BMC Ophthalmol, 2012, 12, 33, doi: 10.1186/1471-2415-12-33.

Additional files

Editorial Notes