Light on glaucoma: the influence of light intensity on perimetry tests and the de Vries-Rose, Weber's and Ferry-Porter's law.

Light on glaucoma: the influence of light intensity on perimetry tests and the de Vries-Rose, Weber's and Ferry-Porter's law. - Light on glaucoma

Status

Active, not recruiting

Phases

Unknown

Study type

Observational

Source

NL-OMON

Registry ID

NL-OMON41039

Enrollment

Registered

2014-10-28

Start date

2015-01-16

Completion date

Unknown

Last updated

2024-04-23

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

Conditions

glaucoma POAG

Interventions

None listed

Eligibility

Age

18 Years to 99 Years

Inclusion criteria

Inclusion criteria: Glaucoma patients aged 18 years or older who visit the ophthalmology outpatient department of the UMCG, provide written informed consent form and meet the inclusion-exclusion criteria.;Healthy subjects will consist of people who have signed in, without ophthalmic abnormalities and provide written informed consent.

Exclusion criteria

Exclusion criteria: Glaucoma patients: - Visual acuity below 0.8 (above 50 years) or below 1.0 (below 50 years of age) - Any other eye disease than glaucoma;Healthy subjects: - Visual acuity below 0.8 (above 50 years) or below 1.0 (below 50 years of age) - Any other eye disease

Design outcomes

Primary

Measure	Time frame
Measurement of (1) the visual field, (2) contrast sensitivity and (3) the critical flicker frequency in different light intensities. (1) The visual field is determined by offering points in different places of the visual field, which increase in light intensity. By repeating the test with grey filters, the influence of the background light on the outcome of the visual field test can be determined. (2) The contrast sensitivity is measured with a set spatial frequency. By repeating the test with grey filters, the influence of the background light on the contrast sensitivity can be determined. This results in a function (contrast sensitivity as a function of light intensity) from which the de Vries-Rose and Weber's law can be confirmed. (3) For the measurement of the critical flicker frequency, the frequency where the flickering light becomes a continue signal is determined. By repeating the test with grey filters, the influence of the background light on the critical flicker frequency can be determined. This results in a function (critical flicker frequency as a function of light intensity) from which Ferry-Porter's law can be confirmed.	—

Measure

Time frame

Measurement of (1) the visual field, (2) contrast sensitivity and (3) the critical flicker frequency in different light intensities. (1) The visual field is determined by offering points in different places of the visual field, which increase in light intensity. By repeating the test with grey filters, the influence of the background light on the outcome of the visual field test can be determined. (2) The contrast sensitivity is measured with a set spatial frequency. By repeating the test with grey filters, the influence of the background light on the contrast sensitivity can be determined. This results in a function (contrast sensitivity as a function of light intensity) from which the de Vries-Rose and Weber's law can be confirmed. (3) For the measurement of the critical flicker frequency, the frequency where the flickering light becomes a continue signal is determined. By repeating the test with grey filters, the influence of the background light on the critical flicker frequency can be determined. This results in a function (critical flicker frequency as a function of light intensity) from which Ferry-Porter's law can be confirmed.

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Countries

Netherlands

Outcome results