Smartphone Flicker Fusion Test for Vision Impairment

Overseen By Jan Full, BSN

Age: 18+

Sex: Any

Trial Phase: Academic

Sponsor: Randy Kardon

Disqualifiers: Scotoma, other ocular disorders

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Compensation: Varies

Number of Visits: 1

500 Participants Needed

Trial Summary

Will I have to stop taking my current medications?

The trial information does not specify whether you need to stop taking your current medications.

What data supports the effectiveness of the treatment eyeFusion for vision impairment?

The research highlights the use of critical flicker fusion frequency (CFF) as a tool to assess visual function, which is relevant to the smartphone-based flicker fusion test in the trial. CFF has been used to evaluate visual function in conditions like cataracts and age-related macular degeneration, suggesting its potential utility in assessing vision impairment. ^{1 2 3 4 5}

How is the eyeFusion treatment different from other treatments for vision impairment?

The eyeFusion treatment is unique because it uses a smartphone-based flicker fusion test to assess vision impairment, which is a novel approach compared to traditional methods. This method leverages technology to potentially offer a more accessible and convenient way to monitor visual function. ^{1 6 7 8 9}

What is the purpose of this trial?

The purpose of this project is to validate a quick, easy-to-use and administer smartphone flicker fusion test. The app (called eyeFusion) can potentially be used to easily and quickly collect critical flicker fusion measurements on patients admitted with optic disorders as part of the clinical care process.

Research Team

Randy Kardon, MD, PhD

Principal Investigator

University of Iowa

Eligibility Criteria

This trial is for people aged 18-80 with or without optic disorders. Healthy individuals with no known eye issues can join as controls, while those experiencing a blind spot (scotoma) are the patient group. Those with other ocular conditions cannot participate.

Inclusion Criteria

I have a blind spot in my vision.

I have no known eye disorders.

Exclusion Criteria

I have another eye condition.

I have a blind spot or another eye condition.

Timeline

Screening

Participants are screened for eligibility to participate in the trial

1-2 weeks

Testing

Participants use the eyeFusion app to measure flicker fusion thresholds

Less than 2 minutes per session

1 visit (in-person)

Follow-up

Participants are monitored for safety and effectiveness after testing

1 week

Treatment Details

Interventions

• eyeFusion

Trial Overview The study is testing an app called eyeFusion on smartphones to see if it's effective in measuring flicker fusion (the speed at which a flickering light appears steady) in patients with optic disorders.

Participant Groups

Group I: eyeFusion Patients Experimental Treatment 1 Intervention

Scotoma subjects aged 18-80.

Group II: eyeFusion Control Subjects Active Control 1 Intervention

Healthy normal controls with no known eye disorders age 18-80.

Who Is Running the Clinical Trial?

Randy Kardon

Lead Sponsor

Trials

4

Recruited

1,100+

Findings from Research

Critical flicker-fusion frequency (CFF) was found to be significantly lower in patients with both non-exsudative and exsudative age-related macular degeneration (AMD), indicating a decline in visual processing speed associated with the disease.

CFF measurements could not differentiate between AMD patients and healthy individuals with similar visual acuity, suggesting that CFF is not a reliable diagnostic tool for AMD.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Critical flicker-fusion frequency in age-related macular degeneration. Maier, M., Groneberg, T., Specht, H., et al.[2021]

Critical flicker/fusion (CFF) thresholds can effectively differentiate between patients with macular disease and those with media opacity, making it a useful potential vision test (PVT) for assessing retinal health.

In a study of 72 patients, CFF values were significantly lower in those with macular disease compared to those with media opacity or pseudophakia, indicating that CFF testing is not affected by media opacity but is sensitive to retinal disease.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Development of a critical flicker/fusion frequency test for potential vision testing in media opacities. Vianya-Estopà, M., Douthwaite, WA., Pesudovs, K., et al.[2004]

The critical flicker fusion frequency (CFF) test is a sensitive tool for detecting visual function changes in cataract patients, effectively distinguishing between simple cataracts and those with additional fundus diseases.

CFF can predict postoperative visual acuity more accurately than traditional tests, especially in cases with dense cataracts, making it a valuable tool for assessing visual prognosis in these patients.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

The theory of critical flicker fusion frequency and its application in cataracts. Xu, G., Fu, J., Qi, H., et al.[2023]

The study tested Augmented Reality Digital spectacles (AR DSpecs) on 21 patients with peripheral visual field losses, showing an average improvement of 18.81% in object detection while walking, indicating enhanced mobility.

The AR DSpecs improved eye tracking behaviors, leading to a more focused gaze on the central path and less scanning, which suggests that these spectacles can effectively aid patients in navigating their environment more safely.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Mobility improvement of patients with peripheral visual field losses using novel see-through digital spectacles. Sayed, AM., Shousha, MA., Baharul Islam, MD., et al.[2020]

Smartphones are becoming essential tools in clinical practice, especially in ophthalmology, where numerous apps can assist with tasks like measuring visual acuity and managing conditions such as amblyopia and glaucoma.

Despite the wide availability of these ophthalmology-related apps, there is a lack of clear evidence supporting their effectiveness, along with concerns about their development, regulation, and data security.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Smartphone use in ophthalmology: What is their place in clinical practice? Hogarty, DT., Hogarty, JP., Hewitt, AW.[2021]

Two tablet-based tests for assessing real-world visual function—face discrimination and visual search—were evaluated in a study with 50 young, normally-sighted adults, showing stable performance estimates after about 20 trials.

Both tests were quick and easy to administer, with high completion rates and understanding among participants, suggesting they could be useful in clinical settings, although further research is needed for older adults and those with visual impairments.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Refinement and preliminary evaluation of two tablet-based tests of real-world visual function. Jones, PR., Tigchelaar, I., Demaria, G., et al.[2021]

The flicker sensitivity assessment technique developed for measuring straylight has been tested on approximately 400 subjects, demonstrating adequate precision and reliability for evaluating retinal integrity and the ability to perform the test.

Normal values for temporal contrast sensitivity (logTCS) were established around 2, with the test remaining unaffected by significant optical deterioration, indicating its robustness in assessing visual function across a wide age range (6 to 85 years).

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Psychophysics, reliability, and norm values for temporal contrast sensitivity implemented on the two alternative forced choice C-Quant device. van den Berg, TJ., Franssen, L., Kruijt, B., et al.[2019]

The study found that critical flicker fusion frequencies (CFF) are significantly reduced in patients with neuropathies compared to those with maculopathies, indicating that CFF can be a useful measure of temporal resolution in different eye conditions.

In amblyopic eyes, CFF is often equal to or better than the dominant eye, regardless of visual acuity, suggesting that CFF testing can help evaluate unexplained visual acuity reductions and highlight a dissociation between visual acuity and temporal resolution in amblyopia.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

[Critical (foveal) flicker fusion frequency (CFF) is helpful in differential diagnosis of organic lesions from orthoptic amblyopias]. Wildberger, H., Junghardt, A., Neetens, A., et al.[2009]

The Accelerator 4-Alternative Forced-Choice Flicker Test prototype (A4FTp) demonstrated comparable diagnostic accuracy to established tests like Frequency Doubling Technology (FDT) and Optical Coherence Tomography (SD-OCT) for detecting chronic open angle glaucoma, with an area under the receiver operator characteristic curve (AUROC) of 0.82.

The A4FTp test is quick, averaging just over 2 minutes per eye, making it a time-efficient option for glaucoma detection compared to traditional methods, which could enhance its practical use in clinical settings.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Development and validation of a new glaucoma screening test using temporally modulated flicker. Fidalgo, BR., Jindal, A., Tyler, CW., et al.[2019]

References

1. Germany pubmed.ncbi.nlm.nih.gov

Critical flicker-fusion frequency in age-related macular degeneration. [2021]

2. United States pubmed.ncbi.nlm.nih.gov

Development of a critical flicker/fusion frequency test for potential vision testing in media opacities. [2004]

3. United States pubmed.ncbi.nlm.nih.gov

The theory of critical flicker fusion frequency and its application in cataracts. [2023]

4. United States pubmed.ncbi.nlm.nih.gov

Mobility improvement of patients with peripheral visual field losses using novel see-through digital spectacles. [2020]

5. United States pubmed.ncbi.nlm.nih.gov

Smartphone use in ophthalmology: What is their place in clinical practice? [2021]

6. England pubmed.ncbi.nlm.nih.gov

Refinement and preliminary evaluation of two tablet-based tests of real-world visual function. [2021]

7. United States pubmed.ncbi.nlm.nih.gov

Psychophysics, reliability, and norm values for temporal contrast sensitivity implemented on the two alternative forced choice C-Quant device. [2019]

8. Germany pubmed.ncbi.nlm.nih.gov

[Critical (foveal) flicker fusion frequency (CFF) is helpful in differential diagnosis of organic lesions from orthoptic amblyopias]. [2009]

9. England pubmed.ncbi.nlm.nih.gov

Development and validation of a new glaucoma screening test using temporally modulated flicker. [2019]