EsotropiaPhase 3NCT00000121
The Prism Adaptation Study (PAS)
A Phase 3 study testing Prisms in Eyeglasses in people with Esotropia, run by National Eye Institute (NEI).
Trial summary
To determine whether the preoperative use of prisms in eyeglasses can improve the outcome of surgery for acquired esotropia, a type of strabismus. To determine whether patients who respond to prism adaptation by developing a new stable angle of -deviation have a better surgical result than do patients who do not… Read more about this study
- Who is it for?
- Ages 3 years and older
- Conditions the study is for
- Esotropia
- What is being tested?
- Prisms in Eyeglasses
- Type of treatment
- Medical device
- How many people
- Not given
- Where
- No sites listed yet
- Study dates
- Mar 1984to May 1989
- Phase
- Phase 3
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 3 years and older
- All sexes
- Child, Adult, Older adult
An eligible male or female must have been age 3 years or older (adults were included) and must have had esotropia that occurred at age 6 months or older, with no history of previous eye muscle surgery.
About this study
To determine whether the preoperative use of prisms in eyeglasses can improve the outcome of surgery for acquired esotropia, a type of strabismus.
To determine whether patients who respond to prism adaptation by developing a new stable angle of -deviation have a better surgical result than do patients who do not respond to prism adaptation.
Read more
To determine whether patients who respond to prism adaptation are more accurately corrected by operating for the prism-adapted angle or the original angle of deviation.
To determine the usefulness of certain input variables (e.g., age at the time of surgery, size of the deviation, visual acuity, binocular function, refractive error) in predicting which patients are more likely to benefit from prism adaptation.
Read the detailed description
Acquired esotropia (crossed eyes that develop after a child reaches the age of 6 months) accounts for 25 percent of all patients with misaligned eyes. Surgery to correct esotropia is done primarily to attain functional use of the two eyes together. The cosmetic aspect of the surgery is secondary. In 40 to 50 percent of cases, more than one operation is needed to accomplish the primary goal, and in some cases even three and four operations are needed.
Preliminary studies from two eye care centers reported that the use of prisms on eyeglasses for about a month before surgery led to good results after a single operation in more than 90 percent of patients. These uncontrolled preliminary studies pointed to the need for a multicenter, randomized, controlled clinical trial designed to prove or disprove scientifically the beneficial effect of prisms.
The Prism Adaptation Study was a double randomization trial involving 286 patients. Three-fifths of the patients were randomly selected for prism adaptation before surgery. Of the patients who responded to the prisms, one-half were randomly selected to have surgery based on the amount of prism required to stabilize the deviation, and the other half had surgery based on the amount of esotropia originally measured. Patients who did not respond to the prisms also had surgery based on the amount of esotropia measured, as did the two-fifths of the patients who did not undergo prism adaptation.
Patients were examined postoperatively at 1 week, 1 month, 3 months, 6 months, and 1 year. An independent examiner, masked to the treatment assignment, evaluated the patient at the 6-month followup. The results were analyzed to determine whether the outcome was better in patients who underwent prism adaptation or in those who underwent conventional treatment. Because the examiner did not know what type of treatment a patient had received, he or she would have no bias in evaluating the results.
- Conditions
- Esotropia
- Being tested
- Prisms in Eyeglasses
- Keywords
- strabismus
- Medical subject headings
- Esotropia, Strabismus
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Prisms in EyeglassesDevice
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted24 Sep 1999 (estimated)
- Study startMar 1984
- Study completionMay 1989
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (2)Papers the sponsor has linked to this study.
- Other trials for EsotropiaStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 3
- Primary purpose
- Treatment
- Allocation
- Randomised
Sponsor and investigators
- Lead sponsor
- National Eye Institute (NEI)
- Sponsor type
- US National Institutes of Health
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT00000121
- Sponsor's protocol ID
- NEI-20
- Status last verified
- Sep 2009
- First submitted
- 23 Sep 1999
- Last updated
- 17 Sep 2009
- Results posted
- No
Publications
Efficacy of prism adaptation in the surgical management of acquired esotropia. Prism Adaptation Study Research Group. Arch Ophthalmol. 1990 Sep;108(9):1248-56. doi: 10.1001/archopht.1990.01070110064026.
PubMed 2100986Repka MX, Connett JE, Scott WE. The one-year surgical outcome after prism adaptation for the management of acquired esotropia. Ophthalmology. 1996 Jun;103(6):922-8. doi: 10.1016/s0161-6420(96)30586-1.
PubMed 8643248
Study at a glance
From the registry record, last updated by the sponsor on 17 Sep 2009. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The Prism Adaptation Study (PAS)
- ClinicalTrials.gov ID
- NCT00000121
- Acronym / sponsor ID
- NEI-20
- Conditions
- Esotropia
- Keywords
- strabismus
- Phase
- Phase 3
- Study type
- Interventional
- Recruitment status
- Completed
- Lead sponsor
- National Eye Institute (NEI)US National Institutes of Health
- Study start
- Mar 1984
- Study completion
- May 1989 (actual)
- First posted
- 24 Sep 1999 (estimated)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
To determine whether the preoperative use of prisms in eyeglasses can improve the outcome of surgery for acquired esotropia, a type of strabismus.
To determine whether patients who respond to prism adaptation by developing a new stable angle of -deviation have a better surgical result than do patients who do not respond to prism adaptation.
To determine whether patients who respond to prism adaptation are more accurately corrected by operating for the prism-adapted angle or the original angle of deviation.
To determine the usefulness of certain input variables (e.g., age at the time of surgery, size of the deviation, visual acuity, binocular function, refractive error) in predicting which patients are more likely to benefit from prism adaptation.
Detailed description
Acquired esotropia (crossed eyes that develop after a child reaches the age of 6 months) accounts for 25 percent of all patients with misaligned eyes. Surgery to correct esotropia is done primarily to attain functional use of the two eyes together. The cosmetic aspect of the surgery is secondary. In 40 to 50 percent of cases, more than one operation is needed to accomplish the primary goal, and in some cases even three and four operations are needed.
Preliminary studies from two eye care centers reported that the use of prisms on eyeglasses for about a month before surgery led to good results after a single operation in more than 90 percent of patients. These uncontrolled preliminary studies pointed to the need for a multicenter, randomized, controlled clinical trial designed to prove or disprove scientifically the beneficial effect of prisms.
The Prism Adaptation Study was a double randomization trial involving 286 patients. Three-fifths of the patients were randomly selected for prism adaptation before surgery. Of the patients who responded to the prisms, one-half were randomly selected to have surgery based on the amount of prism required to stabilize the deviation, and the other half had surgery based on the amount of esotropia originally measured. Patients who did not respond to the prisms also had surgery based on the amount of esotropia measured, as did the two-fifths of the patients who did not undergo prism adaptation.
Patients were examined postoperatively at 1 week, 1 month, 3 months, 6 months, and 1 year. An independent examiner, masked to the treatment assignment, evaluated the patient at the 6-month followup. The results were analyzed to determine whether the outcome was better in patients who underwent prism adaptation or in those who underwent conventional treatment. Because the examiner did not know what type of treatment a patient had received, he or she would have no bias in evaluating the results.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
Who may qualify
- Ages
- 3 years and older
- Sex
- All
- Age groups
- Child, Adult, Older adult
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Prisms in Eyeglasses | Device | – |
Primary outcome
Not reported in the source record.
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 17 Sep 2009.
- Background: PubMed 2100986Efficacy of prism adaptation in the surgical management of acquired esotropia. Prism Adaptation Study Research Group. Arch Ophthalmol. 1990 Sep;108(9):1248-56. doi: 10.1001/archopht.1990.01070110064026.
- Background: PubMed 8643248Repka MX, Connett JE, Scott WE. The one-year surgical outcome after prism adaptation for the management of acquired esotropia. Ophthalmology. 1996 Jun;103(6):922-8. doi: 10.1016/s0161-6420(96)30586-1.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
Questions about this trial
What is this clinical trial studying?
A Phase 3 study testing Prisms in Eyeglasses in people with Esotropia, run by National Eye Institute (NEI).
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 17 Sep 2009. Status can change between updates, so confirm with the study contact before making plans.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 3 studies compare the treatment with the current standard treatment or a placebo in a large group, to confirm how well it works and watch for side effects.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT00000121, which also lists 2 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 17 Sep 2009.