Last updated on September 2017

A Comparison of the Paxos Mobile App to Standard Vision Assessment Tools


Brief description of study

The CLEAR study is testing the level of agreement between in office visual acuity and Amsler grid testing using a mobile vision testing application, Paxos Checkup Study and standard in office methods. In addition the percent of patients able to successfully complete home testing on the digital device will be assessed.

Detailed Study Description

BACKGROUND AND INTRODUCTION Neovascular Age - related Macular Degeneration (AMD) is the most common cause of vision loss in subjects over the age of 60. Today in the US over 15 million people live with some form of AMD, and approximately 1.6-1.75 million people have neovascular AMD associated with vision loss. Approximately 200,000 new cases are diagnosed in the US annually; worldwide, approximately 500,000 new cases are diagnosed each year. With the aging of the overall population, prevalence of all forms of AMD is expected to rise to as many as 42 million by 2030, and it is projected that as many as 8 million seniors are at risk for losing vision from AMD within the next 5 years. Economic analysis indicates that vision impairment and eye disease cost the US an estimated $68 billion annually in healthcare expenditures, reduced productivity, and diminished quality of life, with AMD itself having at least a $30 billion dollar negative impact on gross domestic product. Diabetes is the leading cause of blindness among working-age adults in the United States. According to recent studies funded by the National Eye Institute, diabetic retinopathy, one of the most common and debilitating complications of diabetes, increased by 3.7 million new cases over the last decade. Approximately 7.7 million Americans are now affected by diabetic retinopathy. Even more alarming, the rate is projected to climb to 11 million by 2030. People with diabetes are also at greater risk for cataracts and glaucoma. But diabetic retinopathy (DR) is by far the most common sight-threatening condition among people with diabetes and is the leading cause of blindness in adults aged 20 to 74 years. Diabetic retinopathy has an enormous impact on national health care spending: Twenty-one percent of national medical expenditures for ophthalmic complications are attributable to diabetes. The current standard of care for DR is to identify and treat the disease just before irreversible visual loss occurs. In practice, this means that accurate, early diagnosis of severe Non-Proliferative DR and/or Diabetic Macular Edema (DME) is needed to identify suitable candidates for Laser Photocoagulation, vitrectomy or Intra-vitreal Triamcinolone, as appropriate. Because DR is frequently asymptomatic, and any degree of DR is a risk factor for further progression, annual comprehensive eye exams are recommended for all individuals with diabetes. Use of home - based smartphone visual acuity testing apps has the potential to diagnose and monitor the progression of DR at a very early stage of the disease and to monitor visual changes in macular degeneration. Additionally, The AREDS2-HOME study showed early detection of neovascular AMD resulted in better vision outcomes compared to standard monitoring of neovascular AMD. Identification of changes in vision would trigger further clinical attention and possible interventions. It is conceivable that this would ultimately reduce the economic burden of DR and AMD. DigiSight's Paxos Checkup Mobile Vision Assessment System allows subjects to frequently check their vision in a rapid, quantitative and reproducible way, and transmit that information in a secure and organized fashion, enabling their physicians to optimize and administer treatment in a timely manner. We designed the CLEAR study to evaluate the agreement between Paxos Checkup Application and standard office based visual acuity tests. Because the Paxos Checkup test is a near vision test we are using the Lebensohn Near Card as the main comparator. Recognizing the sensitivity and widespread use of distance visual acuity assessment we will also be testing the Paxos Checkup Application against the Early Test Diabetes Retinopathy Study (ETDRS) visual acuity chart as an exploratory endpoint at selected sites. The ETDRS visual acuity test has been shown in multiple studies to be the most accurate distance vision test in use and therefore has gained widespread acceptance in both research and for regulatory purposes. CLEAR STUDY OBJECTIVES: - Evaluate the performance of the Paxos Checkup visual test device compared to standard in-office procedures for assessing near visual acuity (VA) and metamorphopsia (Amsler grid), and, - Document the ability of patients to perform the Paxos Checkup tests at home and ease of use. OVERVIEW The CLEAR study is a prospective, single arm evaluation of the Paxos Checkup app tests, to be conducted in two phases under a common protocol. In the first phase the comparative performance of the Paxos Checkup to the pre-specified reference methods in assessing near vision and in the presence of normal, AMD or DR will be documented in up to 20 enrolled subjects. Results of the first phase will be used to finalize the protocol and estimated sample size for Phase 2. There will be no formal statistical tests of Phase 1 results, and data from Phase 1 will not be pooled with Phase 2 results. The study will transition from Phase 1 (up to 20 enrolled subjects) to Phase 2 when it is believed that sufficient data have been collected in Phase 1 to plan and implement Phase 2. Phase 2 is expected to enroll between 100 and 150 subjects based on Phase 1 results. Subjects will be enrolled into three subpopulations based on eye health status: subjects with AMD (approximately 50% of total), subjects with DR (approximately 30% of total), and subjects with normal eye health (approximately 20% of total). In Phase 2 the hypotheses associated with the two primary endpoints for the study will be statistically tested against pre-specified performance goals. These performance goals are based on the test-retest correlation of findings from the reference test methods in the study population. Primary Endpoint 1: Near Corrected Visual Acuity (NCVA) assessed with the Paxos Checkup will be compared to the reference method NCVA (Lebensohn Near Card) in replicated measurements at each of two in-office visits. At each office visit, two Paxos Checkup and two reference NCVA assessments will be made (4 assessments in all). The Paxos Checkup and reference methods tests will be administered in an alternating manner to each enrolled subject, with the choice of first test randomly chosen, and with at least 10 minutes between individual tests. Test results for the Paxos Checkup and Lebensohn assessments will be expressed in LogMAR units for purposes of analysis. Primary Endpoint 2: The evaluation of Primary Endpoint 2 is similar to that of Primary Endpoint 1. The Amsler Grid assessment of AMD (outcome: Normal / Abnormal) with the Paxos Checkup will be compared to the reference method Amsler Grid in replicated measurements at each of two in-office visits. At each office visit, two Paxos Checkup and two reference Amsler Grid assessments will be made (4 assessments in all). The Paxos Checkup and reference methods tests will be administered in an alternating manner to each enrolled subject, with the choice of first test randomly chosen, and with at least 10 minutes between individual tests. The Amsler Grid evaluations can be done in parallel with those of CNVA (that is, between CNVA evaluations) for purposes of time efficiency. All subjects, coordinators, Primary Investigators and sponsor will be masked to the aggregate results. The testing sequence is predetermined by the app as visual acuity followed by Amsler grid. Standard in office testing will follow the same sequence. The first test in a subjects sequence of tests will be randomized to either the mobile app or standard methods.

Clinical Study Identifier: NCT02871817

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Larry Singerman, MD

Retinal Associates of Cleveland
Cleveland, OH United States
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Russell J Ivanhoe, MD MBA

Nashville, TN United States
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