Clinical Trial of Peripheral Prism Glasses for Hemianopia

This study has been completed.
Sponsor:
Collaborators:
Chadwick Optical Inc.
Information provided by (Responsible Party):
Schepens Eye Research Institute
ClinicalTrials.gov Identifier:
NCT00494676
First received: June 28, 2007
Last updated: September 23, 2013
Last verified: September 2013
  Purpose

The purpose of this study is to evaluate the functional utility for general mobility (walking) of new high power permanent peripheral prism glasses, which provide visual field expansion device for patients with homonymous hemianopia (the complete loss of half the field of vision on the same side in both eyes). The efficacy of real peripheral prism glasses will be assessed relative to sham peripheral prism glasses.


Condition Intervention
Homonymous Hemianopia
Device: High power (57 prism diopter) peripheral prism glasses
Device: Low power sham peripheral prism glasses

Study Type: Interventional
Study Design: Allocation: Randomized
Endpoint Classification: Efficacy Study
Intervention Model: Crossover Assignment
Masking: Double Blind (Subject, Outcomes Assessor)
Primary Purpose: Treatment
Official Title: Community-based Multi-center Randomized Control Trial of Peripheral Prism Glasses for Hemianopia

Resource links provided by NLM:


Further study details as provided by Schepens Eye Research Institute:

Primary Outcome Measures:
  • Overall Proportion Saying "Yes" to Real Prism Glasses [ Time Frame: Evaluated after 4 weeks of wearing each type of prism glasses ] [ Designated as safety issue: No ]
    At the end of each crossover period, participants were asked a yes/no question: "If the study were to end today, would you want to continue with these prism glasses (i.e. the prism glasses worn in that period)?" The primary outcome was the overall difference, across the two periods of the crossover, between the proportion of participants saying "yes" to real prism glasses and the proportion saying "yes" to sham prism glasses.


Secondary Outcome Measures:
  • Mobility Change Score (All Participants Who Completed Crossover) [ Time Frame: Evaluated after 4 weeks of wearing each type of prism glasses ] [ Designated as safety issue: No ]
    Perceived difficulties with mobility were quantified using a 5-point rating scale (no difficulty to extreme difficulty) for 7 situations (items) relevant to people with hemianopia, including at home, in stores, outdoors, in unfamiliar areas, in familiar areas, in crowded areas, and noticing objects off to the side when walking. The questionnaire was administered at baseline (without prisms) and after each period of the crossover. Interval scale measures of perceived difficulty with overall mobility for each participant were estimated using Rasch analysis of the responses to all seven items (Winsteps software, version 3.70.0.226). Rasch measures were expressed as logits (log odds ratios). Mobility change scores for real and sham prisms were defined as the difference in perceived difficulty relative to baseline (in logits).

  • Mobility Change Score (Only Participants Who Continued Prism Wear in the Long Term) [ Time Frame: Evaluated after 4 weeks of wearing each type of prism glasses ] [ Designated as safety issue: No ]
    Perceived difficulties with mobility were quantified using a 5-point rating scale (no difficulty to extreme difficulty) for 7 situations (items) relevant to people with hemianopia, including at home, in stores, outdoors, in unfamiliar areas, in familiar areas, in crowded areas, and noticing objects off to the side when walking. The questionnaire was administered at baseline (without prisms) and after each period of the crossover. Interval scale measures of perceived difficulty with overall mobility for each participant were estimated using Rasch analysis of the responses to all seven items (Winsteps software, version 3.70.0.226). Rasch measures were expressed as logits (log odds ratios). Mobility change scores for real and sham prisms were defined as the difference in perceived difficulty relative to baseline (in logits).

  • Mobility Change Score (Only Participants Who Discontinued Prism Wear in the Long Term) [ Time Frame: Evaluated after 4 weeks of wearing each type of prism glasses ] [ Designated as safety issue: No ]
    Perceived difficulties with mobility were quantified using a 5-point rating scale (no difficulty to extreme difficulty) for 7 situations (items) relevant to people with hemianopia, including at home, in stores, outdoors, in unfamiliar areas, in familiar areas, in crowded areas, and noticing objects off to the side when walking. The questionnaire was administered at baseline (without prisms) and after each period of the crossover. Interval scale measures of perceived difficulty with overall mobility for each participant were estimated using Rasch analysis of the responses to all seven items (Winsteps software, version 3.70.0.226). Rasch measures were expressed as logits (log odds ratios). Mobility improvement scores for real and sham prisms were defined as the difference in perceived difficulty relative to baseline (in logits).


Enrollment: 73
Study Start Date: September 2007
Study Completion Date: April 2010
Primary Completion Date: July 2009 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: Real prism glasses first, then sham
Participants in this arm will receive high power (57 prism diopter) peripheral prism glasses in the first period of the crossover and low power sham peripheral prism glasses in the second period
Device: High power (57 prism diopter) peripheral prism glasses
All patients will wear two pairs of prism glasses in a crossover design: the high power peripheral prism glasses and sham peripheral prism glasses. Each pair of prism glasses will be worn for four weeks
Device: Low power sham peripheral prism glasses
Low power (5 prism dioptre) prism glasses that provide only about 2 degrees of visual field expansion.
Experimental: Sham prism glasses first, then real
Participants in this arm will receive low power sham peripheral prism glasses in the first period of the crossover and high power (57 prism diopter) peripheral prism glasses in the second period
Device: High power (57 prism diopter) peripheral prism glasses
All patients will wear two pairs of prism glasses in a crossover design: the high power peripheral prism glasses and sham peripheral prism glasses. Each pair of prism glasses will be worn for four weeks
Device: Low power sham peripheral prism glasses
Low power (5 prism dioptre) prism glasses that provide only about 2 degrees of visual field expansion.

Detailed Description:

Patients with hemianopic field loss are unaware of objects in their blind (non-seeing) hemi-field and often experience difficulties with mobility and navigation, such as walking into obstacles on the side of the field loss. In 2000, Peli (2000) described a new peripheral-prism design of prismatic correction for hemianopia, which addresses many of the inadequacies of existing designs of hemianopic visual aids, and produces true field expansion (i.e. the simultaneously seen field is larger with the device than without). In collaboration with the Schepens Eye Research Institute (Boston, MA), Chadwick Optical Inc (White River Junction, VT) has developed a permanent form of Fresnel prism segments, which are made from an acrylic material and can be embedded in a plastic spectacle lens. These permanent prisms offer better cosmesis, optical quality and durability than the temporary 40 prism-diopter press-on Fresnel prism segments used in previous evaluations of the peripheral prism system.

In this study we will evaluate new high-power (57 prism diopter) permanent peripheral prism glasses. The study will employ a crossover design in which each participant will wear a pair of real prism glasses (high-power, 57 prism diopter) and a pair sham prism glasses (low-power, 5 prism diopters, that provide little field expansion) in counterbalanced order. The efficacy of the real prism glasses relative to the sham prism glasses will be assessed for general mobility (walking). We expect that participants will prefer the real prism glasses over the sham prism glasses as the former will be more helpful for obstacle detection when walking.

Prism glasses will be fitted by Low Vision Practitioners at community-based Vision Rehabilitation Clinics. After wearing the first pair of glasses for 4 weeks, participants will return for an in-office follow up visit, at which a questionnaire will be administered to record their experiences of wearing the glasses. The second pair of prism glasses will then be fitted. Another questionnaire will be administered 4 weeks later to record the experiences of wearing the second set of glasses.

At the end of the period of wearing the second pair of prism glasses, a clinical decision will be made as to whether the participant should continue to use the real prism glasses (e.g. if a participant finds the prism glasses helpful for obstacle avoidance when walking). For participants who continue with the prism glasses, a final telephone follow-up interview will be conducted after about 6 months.

  Eligibility

Ages Eligible for Study:   18 Years and older
Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   No
Criteria

Inclusion Criteria:

  • At least 18 years of age.
  • Sighted in both eyes, with monocular visual acuity (best corrected vision), of at least 20/50 in each eye.
  • Complete homonymous hemianopia of more than 3 months duration
  • Refractive error within the -5 dioptre to +5 dioptre range
  • No significant cognitive impairment
  • No history of wearing the Peli system of peripheral prisms for hemianopic field expansion (patients who have worn another type of prismatic correction for hemianopia such as yoked prisms or the Gottlieb VAS system can participate in the study)
  • No physical or mental disabilities, including cognitive dysfunction, balance problems or other deficits that could impair ability to walk or use the peripheral prism spectacles.
  • Able to walk (using a cane or walker is OK) or control the movements of their own wheelchair.
  • In sufficiently good health to attend four in-office visits.

Exclusion Criteria:

  • Diagnosis of dementia
  • Diagnosis of visual neglect
  • History of seizures in the last 6 months
  • Incomplete hemianopia
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its ClinicalTrials.gov identifier: NCT00494676

Locations
United States, Alabama
UAB Center for Low Vision Rehabilitation
Birmingham, Alabama, United States, 35294
United States, California
Vista Center for the Blind and Visually Impaired
Palo Alto, California, United States, 94306
United States, Florida
Visual Health@Jupiter Eye Center
Jupiter, Florida, United States, 33458
United States, Georgia
Emory Optical Low Vision
Atlanta, Georgia, United States, 30322
United States, Illinois
Illinois Eye Institute
Chicago, Illinois, United States, 60616
United States, Indiana
Indiana University School of Optometry, Low Vision Rehabilitation and Primary Care Services
Bloomington, Indiana, United States, 47404
United States, Kansas
University of Kansas Medical Center
Prairie Village, Kansas, United States, 66208
United States, Massachusetts
Schepens Eye Research Institute
Boston, Massachusetts, United States, 02114
Vision Care Specialists, P.C.
Southborough, Massachusetts, United States, 01772
United States, North Carolina
Academy Eye Associates
Durham, North Carolina, United States, 27707
Seven Lakes Eye Care
West End, North Carolina, United States, 27376
United States, Oklahoma
NSU Oklahoma College of Optometry,
Tahlequah, Oklahoma, United States, 74464
United Kingdom
Manchester Royal Eye Hospital
Manchester, United Kingdom, M60 1QD
Sponsors and Collaborators
Schepens Eye Research Institute
Chadwick Optical Inc.
Investigators
Principal Investigator: Alex R Bowers, PhD Schepens Eye Research Institute
Principal Investigator: Karen Keeney, MSBA Chadwick Optical Inc.
  More Information

Publications:
Additional publications automatically indexed to this study by ClinicalTrials.gov Identifier (NCT Number):
Responsible Party: Schepens Eye Research Institute
ClinicalTrials.gov Identifier: NCT00494676     History of Changes
Other Study ID Numbers: 2006-016, R44EY014723
Study First Received: June 28, 2007
Results First Received: July 7, 2013
Last Updated: September 23, 2013
Health Authority: United States: Institutional Review Board

Keywords provided by Schepens Eye Research Institute:
Hemianopia
Mobility
Rehabilitation
Low vision

Additional relevant MeSH terms:
Hemianopsia
Vision Disorders
Sensation Disorders
Neurologic Manifestations
Nervous System Diseases
Blindness
Eye Diseases
Signs and Symptoms
Methamphetamine
Sympathomimetics
Autonomic Agents
Peripheral Nervous System Agents
Physiological Effects of Drugs
Pharmacologic Actions
Dopamine Agents
Neurotransmitter Agents
Molecular Mechanisms of Pharmacological Action
Central Nervous System Stimulants
Central Nervous System Agents
Therapeutic Uses
Adrenergic Agents
Adrenergic Uptake Inhibitors
Neurotransmitter Uptake Inhibitors
Dopamine Uptake Inhibitors

ClinicalTrials.gov processed this record on July 23, 2014