Clinical trial NCT00494676: Clinical Trial of Peripheral Prism Glasses for Hemianopia
Official title: Community-based Multi-center Randomized Control Trial of Peripheral Prism Glasses for Hemianopia
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Homonymous Hemianopia
Keywords: Hemianopia
Mobility
Rehabilitation
Low vision
Lead sponsor: Massachusetts Eye and Ear Infirmary
Sponsor class: OTHER
Collaborators: name: Chadwick Optical Inc.
name: National Eye Institute (NEI)
First posted: 2007-07-02
Enrollment: 73
Sex: ALL
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Allocation: RANDOMIZED
Intervention model: CROSSOVER
Primary purpose: TREATMENT

Brief summary: 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.

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 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

Primary outcomes:
measure: Overall Proportion Saying "Yes" to Real Prism Glasses
timeFrame: Evaluated after 4 weeks of wearing each type of prism glasses
Secondary outcomes:
measure: Mobility Change Score (All Participants Who Completed Crossover)
timeFrame: Evaluated after 4 weeks of wearing each type of prism glasses
measure: Mobility Change Score (Only Participants Who Continued Prism Wear in the Long Term)
timeFrame: Evaluated after 4 weeks of wearing each type of prism glasses
measure: Mobility Change Score (Only Participants Who Discontinued Prism Wear in the Long Term)
timeFrame: Evaluated after 4 weeks of wearing each type of prism glasses
Other outcomes:
Locations:
city: Birmingham
country: United States
facility: UAB Center for Low Vision Rehabilitation
state: Alabama
city: Palo Alto
country: United States
facility: Vista Center for the Blind and Visually Impaired
state: California
city: Jupiter
country: United States
facility: Visual Health@Jupiter Eye Center
state: Florida
city: Atlanta
country: United States
facility: Emory Optical Low Vision
state: Georgia
city: Chicago
country: United States
facility: Illinois Eye Institute
state: Illinois
city: Bloomington
country: United States
facility: Indiana University School of Optometry, Low Vision Rehabilitation and Primary Care Services
state: Indiana
city: Prairie Village
country: United States
facility: University of Kansas Medical Center
state: Kansas
city: Boston
country: United States
facility: Schepens Eye Research Institute
state: Massachusetts
city: Southborough
country: United States
facility: Vision Care Specialists, P.C.
state: Massachusetts
city: Durham
country: United States
facility: Academy Eye Associates
state: North Carolina
city: West End
country: United States
facility: Seven Lakes Eye Care
state: North Carolina
city: Tahlequah
country: United States
facility: NSU Oklahoma College of Optometry,
state: Oklahoma
city: Manchester
country: United Kingdom
facility: Manchester Royal Eye Hospital
Study officials:
affiliation: Schepens Eye Research Institute
name: Alex R Bowers, PhD
role: PRINCIPAL_INVESTIGATOR
affiliation: Chadwick Optical Inc.
name: Karen Keeney, MSBA
role: PRINCIPAL_INVESTIGATOR
References:
citation: 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.
citation: 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.
citation: 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.