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Completed

NCT Number: NCT02023086

Clinical Investigation on the Blood Oxygenation at the Optic Nerve Head in Fabry Patients

This study aimed to evaluate blood oxygenation at the optic nerve head in relation with visual field losses observed in many Fabry patients. Data collected allowed to evaluate if there is a link between these two entities.

Study lasted 2 years during which a limited number of Fabry patients had been compared to a control group to confirm any relationship between blood flow and field losses, and to see if these results varied over time.

HYPOTHESIS

1. Fabry patients will present significant differences in visual fields compared to control 2 There will be variability of the visual field defects on the long term but not on the short term 3 Blood oxygenation will be higher for Fabry patients 4 Blood volume at the optic nerve head will be the same for both groups.

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Key information

Conditions

Fabry Disease Brain Diseases Brain Diseases, Metabolic Brain Diseases, Metabolic, Inborn Cardiovascular Diseases Central Nervous System Diseases Cerebral Small Vessel Diseases Cerebrovascular Disorders Congenital, Hereditary, and Neonatal Diseases and Abnormalities Genetic Diseases, Inborn Genetic Diseases, X-Linked Lipid Metabolism Disorders Lipid Metabolism, Inborn Errors Lipidoses Lysosomal Storage Diseases Lysosomal Storage Diseases, Nervous System Metabolic Diseases Metabolism, Inborn Errors Nervous System Diseases Nutritional and Metabolic Diseases Sphingolipidoses Vascular Diseases

Age range

18 year and older

Sex eligibility

All sexes

Study type

Observational

Primary location

Universite de Montreal

Montreal, Quebec, H3T1P1, Canada

About this study

The first subjects who meet the following criteria will be enrolled in the study.

Inclusion criteria

(Fabry group ):

  • Aged over 18 years old
  • Being diagnosed with Fabry disease
  • 3 subjects will be under enzyme replacement treatment for the treatment of Fabry disease.
  • 3 subjects will not receive enzyme replacement treatment
  • Is fit to give legal consent.
  • Is available for a period of 2 years

Inclusion criteria

(CONTROL group ):

  • Matched for age and sex with group A - 6 participants
  • Being healthy, with no known chronic systemic disease nor acute disease at the moment of the recruitment
  • Is fit to give legal consent.
  • Is available for a period of 2 years

Exclusion criteria

(Both groups):

  • Presents with an active pathological ocular condition
  • Presence of an abnormal optic nerve (congenital or acquired)
  • Usage of topical ocular drug(s) at the time of selection
  • To have known allergy to topical diagnostic drugs used in this study
  • Usage of systemic medication with known effect on the visual field

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

Inclusion criteria

(Fabry group):

  • Aged over 18 years old
  • Being diagnosed with Fabry disease
  • 3 subjects will be under enzyme replacement treatment for the treatment of Fabry disease.
  • 3 subjects will not receive enzyme replacement treatment
  • Is fit to give legal consent.
  • Is available for a period of 2 years

Inclusion criteria

(CONTROL group):

  • Matched for age and sex with group A - 6 participants
  • Being healthy, with no known chronic systemic disease nor acute disease at the moment of the recruitment
  • Is fit to give legal consent.
  • Is available for a period of 2 years

Exclusion criteria

( both groups):

  • Presents with an active pathological ocular condition
  • Presence of an abnormal optic nerve (congenital or acquired)
  • Usage of topical ocular drug(s) at the time of selection
  • To have known allergy to topical diagnostic drugs used in this study
  • Usage of systemic medication with known effect on the visual field

Treatment and study plan

Contrast sensitivity measurement

Procedure

Contrast sensitivity test is made with targets alternating black and white lines. The larger the lines are, easier it is to see them. Targets are distributed in 5 rows, each oriented at a different angle. Contrast sensitivity level is determined by the smallest target seen by the participant, line by line. This test is done under dim lightning with the habitual visual correction worn.

Slit Lamp assessment and intra-ocular pressure measurement

Procedure

Slit lamp is used to assess the presence of significant lens opacities known as Fabry cataracts. In fact, these opacities can induced a bias on the contrast sensitivity measurement and can increase the symptoms felt by the patient. A grade 2 (CFDI grading chart) of lens opacities is considered clinically significant and this will become an exclusion criteria for the following of the study. Intra-ocular pressure will be measured with a non contact tonometer (air pulsed) (Ocular Response Analyser, Reichert Instrumentation.)

Visual field testing

Procedure

Visual field will be assessed with an automated perimeter (Humphrey, Texas) using a threshold strategy. This implies that the subject has to identify not only if he perceives the visual stimulus but the minimal level of this stimulus (in decibels), to be seen, is also recorded. Visual field will be tested up to 30 degrees from the central point of fixation.

In order to measure immediate variability of the visual testing among Fabry subjects, this test will be done at the beginning of the testing session (in the morning) and another time 1h00 later.

Oxygen flow at the optic nerve head measurement

Procedure

Pupils will be dilated with 1 drop of 1% tropicamide. The procedure is similar to the one used for taking a photo of the retina. Each measurement session represents a continuous recording of 20 simultaneous functions of reflectometry from the optic nerve area during 10 seconds.

During all recording sessions, the systemic arterial oxygen saturation will be also monitored at the right index finger using a pulse oximeter (Escort M10, Invivo, Orlando, USA). Arterial blood pressure will be also monitored before and after the testing using a manual sphygmomanometer.

Other names: OSOME

Tropicamide

Drug

Used to dilate patient's pupil during testing

Other names: Mydriacyl® Mydriatic Tropicamide 1% Ophthalmic Drops, DIN 00001007

OSOME

Device

The OSOME system is the only technology able to perform on line and real time capillaries blood oxygenation measurement in the eye. The system operates with 1200 discreet wavelengths between 400 nm to 700 nm with 500 millisecond integration times. It is not invasive, functioning just like a fundus camera.

Other names: (O.S.O.M.E., US patent # 5,919,132;)

Primary outcomes

  1. Blood Oxygenation at the Optic Nerve Head

    Time frame: 2 years

    OSOME measurement of the blood oxygenation at the optic nerve head

Secondary outcomes

  1. Field Defect

    Time frame: 2 years

    Visual field defect using Frequency Doubling Technology (FDT)

    Results from FDT perimetry are reported using decibels of sensitivity. FDT perimetry has a manufacturer-provided internal normative database. (Deviation Plot). Results are compared to the normative database are shown on a gray scale plot based on probability levels. Screening tests preformed with the -5 screening test index ranges from P≥5% (worst) to P<1% (better)

    The global indices that are reported are the mean deviation (MD) and pattern standard deviation (PSD). MD values that fall below 5%, 2% 1% or 0.5 % normal probability levels are indicated with the appropriate label. Pattern Standard Deviation (PSD) represents how evenly the field loss is spread across the VF, thus indicative of localized loss. The PSD can only be equal to or greater than zero. The higher the PSD value, the greater the amount of irregularities with steeper slopes in the VF.

Sponsors and collaborators

Lead sponsor

Université de Montréal

Other

Collaborators

  • Genzyme, a Sanofi Company

Registry information

Official study title

Clinical Investigation on the Blood Oxygenation at the Optic Nerve Head in Relation With Visual Field Loss in Fabry Patients

Important dates

Study start
2014
Primary completion
2016
Study completion
2016
First posted
Dec 30, 2013
Registry last updated
Sep 19, 2024

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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