AmblyopiaNCT03341780
Standard Amblyopia Therapy in Adult Amblyopes
An observational study of Amblyopia, run by Southern California College of Optometry at Marshall B. Ketchum University.
Trial summary
Amblyopia is characterized by a reduction in visual acuity, contrast sensitivity, and binocular visual functions. The two main causes of amblyopia are anisometropia and strabismus which alter the synaptic connections between neurons along the visual pathway. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Amblyopia
- What is being tested?
- amblyopia therapy
- Type of treatment
- Surgery or procedure
- How many people
- 9 participants
- Where
- No sites listed yet
- Study dates
- 16 Dec 2014to 24 Oct 2016
- Phase
- Observational
- 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 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Study population: Subjects will be recruited from the College community and University Eye Clinic. An announcement will be made to the College community and volunteers accepted.
Who may be able to join
- Amblyopic patients with acuities between 20/40 (0.30 logMAR) and 20/400 (1.30 logMAR).
- All subjects will be over the age of 18.
- Prior amblyopia therapy is not an exclusion criteria.
- Subjects will be recruited from the College community and University Eye Clinic.
Who cannot join
- A significant cataract that affects vision.
- Glaucoma, diabetes, uncontrolled high blood pressure.
- Other ocular or systemic diseases that will affect visual acuity.
- The inability to give informed consent.
About this study
Amblyopia is characterized by a reduction in visual acuity, contrast sensitivity, and binocular visual functions. The two main causes of amblyopia are anisometropia and strabismus which alter the synaptic connections between neurons along the visual pathway. Current treatment for amblyopia has indicated that the younger the amblyope, the greater the effect of treatment. The purpose of this study is to determine if standard amblyopia treatment improved visual acuity in adult amblyopes.
Read the detailed description
Functional amblyopia is an optically uncorrectable decrease in visual acuity, i.e., spatial resolution, with no apparent pathological or morphological cause. There are several etiological origins for amblyopia in the human population; anisometropia and strabismus are the two most prevalent etiological factors. Anisometropic amblyopia is a decrease in visual acuity (spatial resolution) that is the result of a large difference in refractive error between the two eyes. Strabismic amblyopia is characterized by an eye misalignment early in life which is associated with a decrease in visual acuity.
The initial site of the defect in amblyopia is the primary visual cortex. The amblyopic eye is placed at a competitive disadvantage to the nonamblyopic eye which results in a reduction in the synapses or cells responding to the amblyopic eye. The conditions associated with amblyopia must be present prior to the end of the critical period of neural development for amblyopia to develop. The neurophysiological systems of anisometropic and strabismic monkeys have differences in the distributions of binocular cortical cells. Anisometropic amblyopic monkeys only exhibit binocular cells that are tuned to low spatial frequencies. If a neuron has a high spatial resolution, it is unlikely that the neuron will be binocular. However, strabismic amblyopic monkeys exhibit few binocular cells and, moreover, there does not appear to be a spatial frequency dependent distribution of these binocular cells. The strabismic subjects typically displayed few binocular cells, regardless of the spatial frequency tuning of the cell.
If the amblyopic eye is compared to the nonamblyopic eye, two important differences are noted. First, the amblyopic eye has a lower contrast sensitivity at high spatial frequencies (and sometimes at all spatial frequencies) than the nonamblyopic eye. This also results in a decrease in visual acuity for the amblyopic eye. Second, the amblyopic eye demonstrates a longer latency for neural transmission than the nonamblyopic eye.
There is very little published on adult amblyopia therapy. This is because clinicians initially believed that amblyopia could not be treated after the end of the critical period. The prevailing theory was that the synaptic contacts between cells could only be modified during the critical period. In children, the majority of the improvement in acuity (80%) takes place in the first 6 weeks of therapy. There is a direct relationship between the hours of patching and the improvement in acuity. Most of the improvement in acuity occurs after the first 100 hours of patching.
There is a linear dose-response function for amblyopia treatment. The logMAR acuity increases 0.1 log unit or 1 chart line per 120 hours of patching. The response does not differ between the types of amblyopia. It has also been demonstrated that there is only a minimal benefit to patching more than 2 hours/day.
In a Pediatric Eye Disease Investigator Group (PEDIG) study, 189 amblyopic children were treated with 2 hours of patching per day. The amblyopic eye acuities ranged from 20/40 - 20/80 before treatment. The average improvement in acuity after 4 months of treatment was 0.24 logMAR (2.4 lines improvement on a logMAR chart). Another study used amblyopes with poorer acuity (20/100 - 20/400 before therapy). After 4 months of patching, the average increase in acuity was 0.48 logMAR (or an increase of 4.8 lines on a logMAR chart). The average acuity went from 20/250 (i.e., 1.10 logMAR) before treatment to 20/63 (i.e., 0.50 logMAR) after treatment. The results were the same for anisometropic amblyopes and strabismic amblyopes. In another study with amblyopes with starting acuity worse than 20/100, the improvement was 3.7 ± 2.5 logMAR chart lines of acuity.
Recent studies have suggested that adult amblyopia can be treated with non-standard therapy. Patching combined with active, near, threshold-training tasks and continuous feedback is employed in these studies. These studies indicate that amblyopia can be treated after the critical period ends. It is suggested that these perceptual learning tasks improve performance in the amblyopic eye by decreasing neural noise. Standard amblyopia therapy typically employed in children has not been investigated in adult amblyopes. The purpose of this study is to use standard amblyopic therapy to determine if there is an enhancement in visual performance in the amblyopic eye of adults.
- Conditions
- Amblyopia
- Being tested
- amblyopia therapy
- Medical subject headings
- Amblyopia
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
amblyopia therapyProcedure or surgery
Any of the following amblyopia training activities may be employed during patching: board games, card games, coloring in O's, comic books, craft projects, crossword puzzles, dot-to-dot patterns, drawing, hammering nails, jacks, jigsaw puzzles, lego and other blocks, marbles, mazes, peg-board activities, perceptual materials, pickup sticks, reading, sewing, shooting games, stringing beads, throwing or hitting games, tracing, and video or computer games.
What is being measured
The primary outcome is the main question the study is designed to answer.
visual acuity
LogMAR acuity will be measured with the eETDRS chart
Measured: 24 weeks
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted14 Nov 2017
- Study start16 Dec 2014
- Primary completion24 Oct 2016
- Study completion24 Oct 2016
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (12)Papers the sponsor has linked to this study.
- Other trials for AmblyopiaStudies 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
- Observational
- Observational model
- Cohort
- Time perspective
- Prospective
- Enrolment
- 9 participants (actual)
Sponsor and investigators
- Lead sponsor
- Southern California College of Optometry at Marshall B. Ketchum University
- Sponsor type
- University, hospital or other
- Collaborators
- Allergan
- Responsible party
- Sponsor
- Investigators
- William Ridder, OD, PhD, Principal investigator, Southern California College of Optometry at Marshall B. Ketchum University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT03341780
- Sponsor's protocol ID
- SoutherCCO
- Status last verified
- Nov 2017
- First submitted
- 9 Nov 2017
- Last updated
- 17 Nov 2017
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided
Publications
von Noorden GK. Amblyopia: a multidisciplinary approach. Proctor lecture. Invest Ophthalmol Vis Sci. 1985 Dec;26(12):1704-16.
PubMed 3934105Michaels DD. Visual optics and refraction: a clinical approach. St Louis, MO: C.V. Mosby Co.; 1980.
Crawford ML, Blake R, Cool SJ, von Noorden GK. Physiological consequences of unilateral and bilateral eye closure in macaque monkeys: some further observations. Brain Res. 1975 Jan 24;84(1):150-4. doi: 10.1016/0006-8993(75)90809-4. No abstract available.
PubMed 1111823Hubel DH, Wiesel TN, LeVay S. Plasticity of ocular dominance columns in monkey striate cortex. Philos Trans R Soc Lond B Biol Sci. 1977 Apr 26;278(961):377-409. doi: 10.1098/rstb.1977.0050. No abstract available.
PubMed 19791Stewart CE, Moseley MJ, Stephens DA, Fielder AR. Treatment dose-response in amblyopia therapy: the Monitored Occlusion Treatment of Amblyopia Study (MOTAS). Invest Ophthalmol Vis Sci. 2004 Sep;45(9):3048-54. doi: 10.1167/iovs.04-0250.
PubMed 15326120Repka MX, Beck RW, Holmes JM, Birch EE, Chandler DL, Cotter SA, Hertle RW, Kraker RT, Moke PS, Quinn GE, Scheiman MM; Pediatric Eye Disease Investigator Group. A randomized trial of patching regimens for treatment of moderate amblyopia in children. Arch Ophthalmol. 2003 May;121(5):603-11. doi: 10.1001/archopht.121.5.603.
PubMed 12742836Holmes JM, Kraker RT, Beck RW, Birch EE, Cotter SA, Everett DF, Hertle RW, Quinn GE, Repka MX, Scheiman MM, Wallace DK; Pediatric Eye Disease Investigator Group. A randomized trial of prescribed patching regimens for treatment of severe amblyopia in children. Ophthalmology. 2003 Nov;110(11):2075-87. doi: 10.1016/j.ophtha.2003.08.001.
PubMed 14597512Holmes JM, Edwards AR, Beck RW, Arnold RW, Johnson DA, Klimek DL, Kraker RT, Lee KA, Lyon DW, Nosel ER, Repka MX, Sala NA, Silbert DI, Tamkins S; Pediatric Eye Disease Investigator Group. A randomized pilot study of near activities versus non-near activities during patching therapy for amblyopia. J AAPOS. 2005 Apr;9(2):129-36. doi: 10.1016/j.jaapos.2004.12.014.
PubMed 15838439Holmes JM, Lazar EL, Melia BM, Astle WF, Dagi LR, Donahue SP, Frazier MG, Hertle RW, Repka MX, Quinn GE, Weise KK; Pediatric Eye Disease Investigator Group. Effect of age on response to amblyopia treatment in children. Arch Ophthalmol. 2011 Nov;129(11):1451-7. doi: 10.1001/archophthalmol.2011.179. Epub 2011 Jul 11.
PubMed 21746970Levi DM, Li RW. Perceptual learning as a potential treatment for amblyopia: a mini-review. Vision Res. 2009 Oct;49(21):2535-49. doi: 10.1016/j.visres.2009.02.010. Epub 2009 Feb 27.
PubMed 19250947Levi DM, Li RW. Improving the performance of the amblyopic visual system. Philos Trans R Soc Lond B Biol Sci. 2009 Feb 12;364(1515):399-407. doi: 10.1098/rstb.2008.0203.
PubMed 19008199Ridder WH 3rd, Rouse MW. Predicting potential acuities in amblyopes: predicting post-therapy acuity in amblyopes. Doc Ophthalmol. 2007 May;114(3):135-45. doi: 10.1007/s10633-007-9048-y. Epub 2007 Feb 20.
PubMed 17310345
Study at a glance
From the registry record, last updated by the sponsor on 17 Nov 2017. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Standard Amblyopia Therapy in Adult Amblyopes
- ClinicalTrials.gov ID
- NCT03341780
- Acronym / sponsor ID
- SoutherCCO
- Conditions
- Amblyopia
- Study type
- Observational
- Recruitment status
- Completed
- Enrolment
- 9 participants (actual)
- Lead sponsor
- Southern California College of Optometry at Marshall B. Ketchum UniversityUniversity, hospital or other
- Collaborators
- Allergan
- Study start
- 16 Dec 2014 (actual)
- Primary completion
- 24 Oct 2016 (actual)
- Study completion
- 24 Oct 2016 (actual)
- First posted
- 14 Nov 2017 (actual)
- 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.
Amblyopia is characterized by a reduction in visual acuity, contrast sensitivity, and binocular visual functions. The two main causes of amblyopia are anisometropia and strabismus which alter the synaptic connections between neurons along the visual pathway. Current treatment for amblyopia has indicated that the younger the amblyope, the greater the effect of treatment. The purpose of this study is to determine if standard amblyopia treatment improved visual acuity in adult amblyopes.
Detailed description
Functional amblyopia is an optically uncorrectable decrease in visual acuity, i.e., spatial resolution, with no apparent pathological or morphological cause. There are several etiological origins for amblyopia in the human population; anisometropia and strabismus are the two most prevalent etiological factors. Anisometropic amblyopia is a decrease in visual acuity (spatial resolution) that is the result of a large difference in refractive error between the two eyes. Strabismic amblyopia is characterized by an eye misalignment early in life which is associated with a decrease in visual acuity.
The initial site of the defect in amblyopia is the primary visual cortex. The amblyopic eye is placed at a competitive disadvantage to the nonamblyopic eye which results in a reduction in the synapses or cells responding to the amblyopic eye. The conditions associated with amblyopia must be present prior to the end of the critical period of neural development for amblyopia to develop. The neurophysiological systems of anisometropic and strabismic monkeys have differences in the distributions of binocular cortical cells. Anisometropic amblyopic monkeys only exhibit binocular cells that are tuned to low spatial frequencies. If a neuron has a high spatial resolution, it is unlikely that the neuron will be binocular. However, strabismic amblyopic monkeys exhibit few binocular cells and, moreover, there does not appear to be a spatial frequency dependent distribution of these binocular cells. The strabismic subjects typically displayed few binocular cells, regardless of the spatial frequency tuning of the cell.
If the amblyopic eye is compared to the nonamblyopic eye, two important differences are noted. First, the amblyopic eye has a lower contrast sensitivity at high spatial frequencies (and sometimes at all spatial frequencies) than the nonamblyopic eye. This also results in a decrease in visual acuity for the amblyopic eye. Second, the amblyopic eye demonstrates a longer latency for neural transmission than the nonamblyopic eye.
There is very little published on adult amblyopia therapy. This is because clinicians initially believed that amblyopia could not be treated after the end of the critical period. The prevailing theory was that the synaptic contacts between cells could only be modified during the critical period. In children, the majority of the improvement in acuity (80%) takes place in the first 6 weeks of therapy. There is a direct relationship between the hours of patching and the improvement in acuity. Most of the improvement in acuity occurs after the first 100 hours of patching.
There is a linear dose-response function for amblyopia treatment. The logMAR acuity increases 0.1 log unit or 1 chart line per 120 hours of patching. The response does not differ between the types of amblyopia. It has also been demonstrated that there is only a minimal benefit to patching more than 2 hours/day.
In a Pediatric Eye Disease Investigator Group (PEDIG) study, 189 amblyopic children were treated with 2 hours of patching per day. The amblyopic eye acuities ranged from 20/40 - 20/80 before treatment. The average improvement in acuity after 4 months of treatment was 0.24 logMAR (2.4 lines improvement on a logMAR chart). Another study used amblyopes with poorer acuity (20/100 - 20/400 before therapy). After 4 months of patching, the average increase in acuity was 0.48 logMAR (or an increase of 4.8 lines on a logMAR chart). The average acuity went from 20/250 (i.e., 1.10 logMAR) before treatment to 20/63 (i.e., 0.50 logMAR) after treatment. The results were the same for anisometropic amblyopes and strabismic amblyopes. In another study with amblyopes with starting acuity worse than 20/100, the improvement was 3.7 ± 2.5 logMAR chart lines of acuity.
Recent studies have suggested that adult amblyopia can be treated with non-standard therapy. Patching combined with active, near, threshold-training tasks and continuous feedback is employed in these studies. These studies indicate that amblyopia can be treated after the critical period ends. It is suggested that these perceptual learning tasks improve performance in the amblyopic eye by decreasing neural noise. Standard amblyopia therapy typically employed in children has not been investigated in adult amblyopes. The purpose of this study is to use standard amblyopic therapy to determine if there is an enhancement in visual performance in the amblyopic eye of adults.
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
- Study population
- Subjects will be recruited from the College community and University Eye Clinic. An announcement will be made to the College community and volunteers accepted.
Key inclusion criteria (4 listed)
- Amblyopic patients with acuities between 20/40 (0.30 logMAR) and 20/400 (1.30 logMAR).
- All subjects will be over the age of 18.
- Prior amblyopia therapy is not an exclusion criteria.
- Subjects will be recruited from the College community and University Eye Clinic.
Key exclusion criteria (4 listed)
- A significant cataract that affects vision.
- Glaucoma, diabetes, uncontrolled high blood pressure.
- Other ocular or systemic diseases that will affect visual acuity.
- The inability to give informed consent.
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 |
|---|---|---|
| amblyopia therapyAny of the following amblyopia training activities may be employed during patching: board games, card games, coloring in O's, comic books, craft projects, crossword puzzles, dot-to-dot patterns, drawing, hammering nails, jacks, jigsaw puzzles, lego and other blocks, marbles, mazes, peg-board activities, perceptual materials, pickup sticks, reading, sewing, shooting games, stringing beads, throwing or hitting games, tracing, and video or computer games. | Procedure or surgery | – |
Primary outcome
visual acuity
Time frame: 24 weeks
LogMAR acuity will be measured with the eETDRS chart
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 Nov 2017.
- Background: PubMed 3934105von Noorden GK. Amblyopia: a multidisciplinary approach. Proctor lecture. Invest Ophthalmol Vis Sci. 1985 Dec;26(12):1704-16.
- BackgroundMichaels DD. Visual optics and refraction: a clinical approach. St Louis, MO: C.V. Mosby Co.; 1980.
- Background: PubMed 1111823Crawford ML, Blake R, Cool SJ, von Noorden GK. Physiological consequences of unilateral and bilateral eye closure in macaque monkeys: some further observations. Brain Res. 1975 Jan 24;84(1):150-4. doi: 10.1016/0006-8993(75)90809-4. No abstract available.
- Background: PubMed 19791Hubel DH, Wiesel TN, LeVay S. Plasticity of ocular dominance columns in monkey striate cortex. Philos Trans R Soc Lond B Biol Sci. 1977 Apr 26;278(961):377-409. doi: 10.1098/rstb.1977.0050. No abstract available.
- Background: PubMed 15326120Stewart CE, Moseley MJ, Stephens DA, Fielder AR. Treatment dose-response in amblyopia therapy: the Monitored Occlusion Treatment of Amblyopia Study (MOTAS). Invest Ophthalmol Vis Sci. 2004 Sep;45(9):3048-54. doi: 10.1167/iovs.04-0250.
- Background: PubMed 12742836Repka MX, Beck RW, Holmes JM, Birch EE, Chandler DL, Cotter SA, Hertle RW, Kraker RT, Moke PS, Quinn GE, Scheiman MM; Pediatric Eye Disease Investigator Group. A randomized trial of patching regimens for treatment of moderate amblyopia in children. Arch Ophthalmol. 2003 May;121(5):603-11. doi: 10.1001/archopht.121.5.603.
- Background: PubMed 14597512Holmes JM, Kraker RT, Beck RW, Birch EE, Cotter SA, Everett DF, Hertle RW, Quinn GE, Repka MX, Scheiman MM, Wallace DK; Pediatric Eye Disease Investigator Group. A randomized trial of prescribed patching regimens for treatment of severe amblyopia in children. Ophthalmology. 2003 Nov;110(11):2075-87. doi: 10.1016/j.ophtha.2003.08.001.
- Background: PubMed 15838439Holmes JM, Edwards AR, Beck RW, Arnold RW, Johnson DA, Klimek DL, Kraker RT, Lee KA, Lyon DW, Nosel ER, Repka MX, Sala NA, Silbert DI, Tamkins S; Pediatric Eye Disease Investigator Group. A randomized pilot study of near activities versus non-near activities during patching therapy for amblyopia. J AAPOS. 2005 Apr;9(2):129-36. doi: 10.1016/j.jaapos.2004.12.014.
- Background: PubMed 21746970Holmes JM, Lazar EL, Melia BM, Astle WF, Dagi LR, Donahue SP, Frazier MG, Hertle RW, Repka MX, Quinn GE, Weise KK; Pediatric Eye Disease Investigator Group. Effect of age on response to amblyopia treatment in children. Arch Ophthalmol. 2011 Nov;129(11):1451-7. doi: 10.1001/archophthalmol.2011.179. Epub 2011 Jul 11.
- Background: PubMed 19250947Levi DM, Li RW. Perceptual learning as a potential treatment for amblyopia: a mini-review. Vision Res. 2009 Oct;49(21):2535-49. doi: 10.1016/j.visres.2009.02.010. Epub 2009 Feb 27.
- Background: PubMed 19008199Levi DM, Li RW. Improving the performance of the amblyopic visual system. Philos Trans R Soc Lond B Biol Sci. 2009 Feb 12;364(1515):399-407. doi: 10.1098/rstb.2008.0203.
- Background: PubMed 17310345Ridder WH 3rd, Rouse MW. Predicting potential acuities in amblyopes: predicting post-therapy acuity in amblyopes. Doc Ophthalmol. 2007 May;114(3):135-45. doi: 10.1007/s10633-007-9048-y. Epub 2007 Feb 20.
- Individual participant dataSharing planned: Undecided
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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.
William Ridder, OD, PhD principal investigator
Southern California College of Optometry at Marshall B. Ketchum University
Questions about this trial
What is this clinical trial studying?
An observational study of Amblyopia, run by Southern California College of Optometry at Marshall B. Ketchum University.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 4 inclusion and 4 exclusion criteria. 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 Nov 2017. 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.
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.
What does the primary outcome measure?
visual acuity (time frame: 24 weeks). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT03341780, which also lists 12 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 Nov 2017.