An interventional study of Multi-Periscopic Prism (MPP) glasses and Fresnel Peripheral Prism (FPP) glasses in Homonymous Hemianopia, sponsored by Massachusetts Eye and Ear Infirmary. Completed at 8 sites in United States. Open to participants aged 7 Years and older. Per ClinicalTrials.gov, last updated 2026-08-19.
Sponsored by Massachusetts Eye and Ear Infirmary · Not applicable, Interventional, and Treatment
This clinical trial will evaluate the efficacy of two types of high-power prism glasses that provide field of view expansion for patients with homonymous hemianopia (the complete loss of half the field of vision on the same side in both eyes).
Patients with hemianopic field loss may be unaware of objects in their blind (non-seeing) hemi-field and often experience difficulties with hazards, such as walking into obstacles on the side of the field loss. Prism glasses that provide field of view expansion may be helpful in detecting hazards on the blind side. In this clinical trial, two types of high power prism glasses will be evaluated. A new design of prisms, Multi-Periscopic Prisms (MPP), will be compared to commercially-available permanent Fresnel peripheral prism (FPP) glasses. The extent to which the prismatic devices improve detection of hazards on the side of the field loss and are helpful when walking will be evaluated.
Participants will try each type of prism glasses at home for 4 weeks in counterbalanced order. Prism glasses will be fitted by Low Vision Practitioners at vision rehabilitation clinics. Participants will attend in-office study visits before and after wearing each type of prism glasses. At the in-office visits they will complete a test that involves detecting pedestrian hazards in a video simulating a walk through a busy shopping mall (virtual reality, VR, walking simulator test). In addition, they may be asked to complete questionnaires to record their experiences of using the prism glasses.
After wearing the second pair of prism glasses, participants will be asked to complete a questionnaire comparing the two types of prism glasses and to select their preferred type. A clinical decision will be made as to whether the participant should continue to use either the first or second pair of prism glasses (e.g. if a participant finds one pair of prism glasses helpful for obstacle avoidance when walking). For participants who continue with the prism glasses, telephone follow-up interviews will be conducted after about 6 and 12 months.
Exclusion Criteria:
Participants in this arm will receive the MPP in the first period of the crossover and the FPP in the second period.
Device: Multi-Periscopic Prism (MPP) glasses · Device: Fresnel Peripheral Prism (FPP) glasses
Participants in this arm will receive the FPP in the first period of the crossover and the MPP in the second period.
Device: Multi-Periscopic Prism (MPP) glasses · Device: Fresnel Peripheral Prism (FPP) glasses
Spectacles with multi-periscopic prisms mounted as oblique peripheral prism segments
Spectacles with conventional permanent Fresnel prisms mounted as oblique peripheral prism segments
Improvement in Blind-side Detection Rate for Hazards Approaching at a Bearing Angle of 40 Degrees
Improvement in detection rate with prism glasses for hazards approaching from the blind side at a bearing angle of 40 degrees in the VR walking simulator test. Improvement is a binary outcome, defined as blind-side detection rate (number of pedestrians detected as a percentage of the total number of pedestrian events) which is significantly higher (z-test for two proportions) with than without prism glasses at the same visit.
Time frame: Immediately after each 4-week intervention
Improvement in Blind-side Detection Rate for Hazards Approaching at a Bearing Angle of 20 Degrees
Improvement in detection rate with prism glasses for hazards approaching from the blind side at a bearing angle of 20 degrees in the VR walking simulator test. Improvement is a binary outcome, defined as blind-side detection rate (number of pedestrians detected as a percentage of the total number of pedestrian events) which is significantly higher (z-test for two proportions) with than without prism glasses at the same visit.
Time frame: Immediately after each 4-week intervention
Device Preference
Number of participants selecting each device as a percentage of the total number of participants enrolled
Time frame: Immediately after the second 4-week intervention
Participants were recruited between April 2023 and November 2024 at seven vision rehabilitation clinics in the United States, including three university clinics, three academic medical centers and one private practice.
| Milestone | MPP First, FPP Second | FPP First, MPP Second |
|---|---|---|
| Started | 18 | 20 |
| Completed | 17 | 17 |
| Not completed | 1 | 3 |
| Withdrew: Withdrawal by subject | 1 | 3 |
| Milestone | MPP First, FPP Second | FPP First, MPP Second |
|---|---|---|
| Started | 17 | 17 |
| Completed | 16 | 16 |
| Not completed | 1 | 1 |
| Withdrew: Withdrawal by subject | 1 | 1 |
Improvement in detection rate with prism glasses for hazards approaching from the blind side at a bearing angle of 40 degrees in the VR walking simulator test. Improvement is a binary outcome, defined as blind-side detection rate (number of pedestrians detected as a percentage of the total number of pedestrian events) which is significantly higher (z-test for two proportions) with than without prism glasses at the same visit.
| Participants | All Participants Who Were Allocated |
|---|---|
| Improved with MPPs | 12 |
| Improved with FPPs | 10 |
Improvement in detection rate with prism glasses for hazards approaching from the blind side at a bearing angle of 20 degrees in the VR walking simulator test. Improvement is a binary outcome, defined as blind-side detection rate (number of pedestrians detected as a percentage of the total number of pedestrian events) which is significantly higher (z-test for two proportions) with than without prism glasses at the same visit.
| Participants | All Participants Who Were Allocated |
|---|---|
| Improved with MPPs | 14 |
| Improved with FPPs | 16 |
Number of participants selecting each device as a percentage of the total number of participants enrolled
| Participants | Participants Who Completed the Crossover |
|---|---|
| Preferred MPPs | 13 |
| Preferred FPPs | 19 |
Collected over From the start of the first 4-week intervention period to the end of the second 4-week intervention period, up to 8 weeks. Non-serious events are listed at a 0% frequency threshold.
| Group | Deaths | Serious | Other |
|---|---|---|---|
| MPP All Participants | 0/38 (0%) | 0/38 (0%) | 0/38 (0%) |
| FPP All Participants | 0/38 (0%) | 0/38 (0%) | 0/38 (0%) |
| Age, Continuous(Years) | MPP First, FPP Second | FPP First, MPP Second | Total |
|---|---|---|---|
| Median | 57 (48 to 65) | 57 (34 to 69) | 57 (35 to 67) |
| Sex: Female, Male(Participants) | MPP First, FPP Second | FPP First, MPP Second | Total |
|---|---|---|---|
| Female | 4 | 7 | 11 |
| Male | 14 | 13 | 27 |
| Race (NIH/OMB)(Participants) | MPP First, FPP Second | FPP First, MPP Second | Total |
|---|---|---|---|
| American Indian or Alaska Native | 0 | 0 | 0 |
| Asian | 0 | 0 | 0 |
| Native Hawaiian or Other Pacific Islander | 0 | 0 | 0 |
| Black or African American | 4 | 2 | 6 |
| White | 14 | 15 | 29 |
| More than one race | 0 | 0 | 0 |
| Unknown or Not Reported | 0 | 3 | 3 |
| Ethnicity (NIH/OMB)(Participants) | MPP First, FPP Second | FPP First, MPP Second | Total |
|---|---|---|---|
| Hispanic or Latino | 2 | 3 | 5 |
| Not Hispanic or Latino | 16 | 17 | 33 |
| Unknown or Not Reported | 0 | 0 | 0 |
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Massachusetts Eye and Ear Infirmary