Clinical Trial of Peripheral Prism Glasses for Hemianopia

Community-based Multi-center Randomized Control Trial of Peripheral Prism Glasses for Hemianopia

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.

Study Overview

• Status: Completed
• Conditions: Homonymous Hemianopia
• Intervention / Treatment: Device: High power (57 prism diopter) peripheral prism glasses; Device: Low power sham peripheral prism glasses

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.

• Study Type: Interventional
• Enrollment (Actual): 73
• Phase: Not Applicable

Contacts and Locations

Study Locations

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

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

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

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
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.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Overall Proportion Saying "Yes" to Real Prism Glasses	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.	Evaluated after 4 weeks of wearing each type of prism glasses

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Mobility Change Score (All Participants Who Completed Crossover)	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).	Evaluated after 4 weeks of wearing each type of prism glasses
Mobility Change Score (Only Participants Who Continued Prism Wear in the Long Term)	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).	Evaluated after 4 weeks of wearing each type of prism glasses
Mobility Change Score (Only Participants Who Discontinued Prism Wear in the Long Term)	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).	Evaluated after 4 weeks of wearing each type of prism glasses

Collaborators and Investigators

• Sponsor: Alexandra Bowers
• Collaborators: National Eye Institute (NEI); Chadwick Optical Inc.
• Investigators: Principal Investigator: Alex R Bowers, PhD, Schepens Eye Research Institute; Principal Investigator: Karen Keeney, MSBA, Chadwick Optical Inc.

Publications and helpful links

General Publications

• Peli E. Field expansion for homonymous hemianopia by optically induced peripheral exotropia. Optom Vis Sci. 2000 Sep;77(9):453-64. doi: 10.1097/00006324-200009000-00006.
• Bowers AR, Keeney K, Peli E. Community-based trial of a peripheral prism visual field expansion device for hemianopia. Arch Ophthalmol. 2008 May;126(5):657-64. doi: 10.1001/archopht.126.5.657.
• Bowers AR, Keeney K, Peli E. Randomized crossover clinical trial of real and sham peripheral prism glasses for hemianopia. JAMA Ophthalmol. 2014 Feb;132(2):214-22. doi: 10.1001/jamaophthalmol.2013.5636.

Helpful Links

• Dr Eli Peli's Vision Rehabilitation Lab at Schepens Eye Research Institute

Study record dates

Study Major Dates

• Study Start: September 1, 2007
• Primary Completion (Actual): July 1, 2009
• Study Completion (Actual): April 1, 2010

Study Registration Dates

• First Submitted: June 28, 2007
• First Submitted That Met QC Criteria: June 29, 2007
• First Posted (Estimate): July 2, 2007

Study Record Updates

• Last Update Posted (Actual): April 4, 2017
• Last Update Submitted That Met QC Criteria: April 1, 2017
• Last Verified: April 1, 2017

More Information

Terms related to this study

• Keywords: Rehabilitation; Mobility; Hemianopia; Low vision
• Additional Relevant MeSH Terms: Nervous System Diseases; Eye Diseases; Neurologic Manifestations; Sensation Disorders; Vision Disorders; Blindness; Hemianopsia; Physiological Effects of Drugs; Adrenergic Agents; Neurotransmitter Agents; Molecular Mechanisms of Pharmacological Action; Autonomic Agents; Peripheral Nervous System Agents; Neurotransmitter Uptake Inhibitors; Membrane Transport Modulators; Dopamine Agents; Dopamine Uptake Inhibitors; Central Nervous System Stimulants; Sympathomimetics; Adrenergic Uptake Inhibitors; Methamphetamine
• Other Study ID Numbers: 2006-016; R44EY014723 (U.S. NIH Grant/Contract)