Polarization Perception in Health and Disease. Testing a New Sight Test

Cataract Clinical Trial

— TaNSiT  

Official title:

Polarization Perception in Health and Disease. Testing a New Sight Test: The TaNSiT Study

Clinical Trial Details — Status: Recruiting

Administrative data

• NCT number: NCT03823092
• Other study ID #: 17/WA/0180
• Status: Recruiting
• Start date: November 9, 2017
• Est. completion date: July 2019

Study information

• Verified date: January 2019
• Source: South Warwickshire NHS Foundation Trust
• Contact: Gary P Misson, PhD FRCOphth
• Phone: +44 01926495321
• Email: gary.misson[@]swft.nhs.uk
• Is FDA regulated: No
• Study type: Observational

Clinical Trial Summary

A study to assess the utility of human polarization pattern perception for the detection, diagnosis and monitoring of eye disease

Description:

The recently described high sensitivity of the human eye to differentiate small angular differences in linear polarization and evidence supporting its macular origin (Misson, Anderson; 2017) suggests that human polarization sensitivity might be a useful diagnostic tool for macular disease. This augments a previous study in which we demonstrated the ability of the human visual system to detect isochromatic isoluminant polarization modulated pattern stimuli (Misson et al 2015).

This is an exploratory 'proof-of-concept' study to determine the clinical value of polarization pattern perception, PPP, in health and disease. We further propose that PPP might be valuable for the diagnosis, monitoring and early detection of macular disease. The latter includes common blinding conditions such as age related macular degeneration and diabetic retinopathy. It is also intended to investigate the effect of cataracts and cataract surgery on PPP: cataract surgery modifies the optics of the eye so might also modify PPP.

PPP is measured using a modification of the methodology described in (Misson et al 2015) and (Misson, Anderson; 2017) whereby polarization modulated patterns are presented on a modified LCD display. The observer's task is to report if they see an image and to describe the image. Images comprise simple patterns or traditional optotypes. A standard set of images are presented in pseudorandom order and the response recorded. A total score, the polarization pattern perception score PPP is then determined from the number of images seen/identified. A more refined metric, the polarization visual acuity pVA, will be derived from the response to the optotype stimuli. These data are then compared to conventional tests of visual structure and function including logMAR visual acuity, ocular examination and OCT scan data.

The study in anticipated to comprise:

Phase 1. Normative Evaluation: observational prospective cross-sectional.. A preliminary normative study will be undertaken on staff members. The aim is to quantify normative values in preparation for the clinical studies.

Hypotheses to be tested:

1. that healthy subjects can perceive polarization stimuli

2. that there is a threshold of polarization image resolution (pVA) analogous to visual acuity. Normative PPP and pVA data will be collected.

Phase 2 Patient Group: observational Prospective cross-sectional / case-control.

Phase 2 subjects will comprise normals and patients with cataracts/pseudophakia and/or AMD, other macular pathology, diabetic retinopathy..

The aim of this phase is to determine the effect, if any, of particular eye conditions on pVA/PPP alone and in comparison with other test parameters.

Hypotheses to be tested:

1. that eye conditions affect pVA/PPP

2. that specific eye conditions have a selective effect on pVA/PPP

3. that pseudophakia affects pVA/PPP

Phase 3: Cataract pre-op v post op pVA/PPP: prospective interventional case-control.

Timescale:concurrent with Phase 2 A subset of the phase 2 cataract patients will undergo cataract surgery according to clinical need. These patients are routinely reviewed 4 - 8 weeks post-op when the opportunity will arise to repeat pVA/PPP measurement. The fellow eye will serve as a control / provide data for repeatability assessment.

The aims of this phase are

1. to determine the repeatability of pVA/PPP testing in a heterogeneous patient group

2. to determine the effect of cataract surgery on the pre-operative pVA/PPP results

3. to determine if pVA/PPP is a useful determinant of post-operative visual outcome.

Hypotheses:

1. that pVA/PPP testing is repeatable

2. that there is a difference in pVA/PPP pre and post cataract surgery

Recruitment information / eligibility

• Status: Recruiting
• Enrollment: 300
• Est. completion date: July 2019
• Est. primary completion date: April 2019
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: All
• Age group: 18 Years and older

Eligibility

Inclusion Criteria:

• willing and able to provide informed consent

Exclusion Criteria:

• unwilling or unable to provide informed consent

• individuals wishing to exit the study

Related Conditions & MeSH terms

• Age Related Macular Degeneration
• Cataract
• Diabetic Retinopathy
• Macular Degeneration
• Macular Disease
• Pseudophakia
• Retinal Disease
• Retinal Diseases

Intervention

Diagnostic Test:
• polarization sensitivity
test of polarization vision as described in Study Description

Locations

Country	Name	City	State
United Kingdom	South Warwickshire NHS Foundation Trust	Warwick	Warwickshire

Sponsors (2)

Lead Sponsor	Collaborator
South Warwickshire NHS Foundation Trust	Aston University

Country where clinical trial is conducted

United Kingdom, 

References & Publications (2)

Misson GP, Anderson SJ. The spectral, spatial and contrast sensitivity of human polarization pattern perception. Sci Rep. 2017 Nov 29;7(1):16571. doi: 10.1038/s41598-017-16873-6. — View Citation

Misson GP, Timmerman BH, Bryanston-Cross PJ. Human perception of visual stimuli modulated by direction of linear polarization. Vision Res. 2015 Oct;115(Pt A):48-57. doi: 10.1016/j.visres.2015.08.004. Epub 2015 Aug 28. — View Citation

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	polarization sensitivity	determine and compare polarization sensitivity between groups	18 month