Corneal AstigmatismNCT03264534
Manually Performed Limbal Relaxing Incisions vs Femtosecond Laser-guided Astigmatic Keratotomy
A study testing limbal relaxing incisions and astigmatic keratotomy in people with Corneal Astigmatism, run by Assiut University at 1 site in Egypt.
Trial summary
Astigmatic keratotomy (AK) is used to treat numerous refractive disorders, including congenital astigmatism, residual corneal astigmatism at the time of or following cataract surgery, post-traumatic astigmatism, and astigmatism after corneal transplantation. Read more about this study
- Who is it for?
- Ages 21 to 65 years
- Conditions the study is for
- Corneal Astigmatism
- What is being tested?
- limbal relaxing incisions and astigmatic keratotomy
- Type of treatment
- Surgery or procedure
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 90 participants
- Where
- 1 siteEgypt
- Study dates
- 21 Mar 2018to 15 Jan 2022
- Phase
- Interventional
- 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 21 to 65 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- patients who have undergo phacoemulsification.
- Clear cornea.
- Astigmatism from 1 diopter up to 4 diopters
Who cannot join
- corneal opacity.
- History of corneal surgery.
- Thin cornea.
- Other cause of diminution of vision rather than corneal astigmatism (eg: optic disc atrophy \& maculopathy).
- Astigmatism less than 1 diopter and more than 4 diopters.
Trial locations and contacts
1 site in 1 country.
About this study
Official title: Manually Performed Limbal Relaxing Incisions vs Femtosecond Laser-guided Astigmatic Keratotomy for Correction of Corneal Astigmatism After Phacoemulsification
Astigmatic keratotomy (AK) is used to treat numerous refractive disorders, including congenital astigmatism, residual corneal astigmatism at the time of or following cataract surgery, post-traumatic astigmatism, and astigmatism after corneal transplantation.
Within the past few years, much consideration has been given to an evolutionary variant of the procedure, the limbal relaxing incision (LRI). By moving the incision farther to the periphery, cataract surgeons can safely and predictably remediate mild to moderate amounts of regular astigmatism at the time of cataract surgery by performing this incisional technique.
Recent technological developments have shifted ophthalmologist's attention from manually created LRIs and astigmatic keratotomy procedures to femtosecond laser-guided procedures. Femtosecond lasers offer superior incisional accuracy and reproducibility coupled with minimal effects on collateral tissues, achieving levels of safety and reproducibility exceeding those of mechanical techniques. A major clinical application of the femtosecond laser is for creating arcuate incisions that have a precise and accurate length, depth, angular position, and optical zone.
Read the detailed description
Pre-operative evaluation:
- Close examination of the peripheral cornea by slit lamb, particularly in the areas where the incisions will be placed.
- Fundus examination to exclude other causes of diminution of vision.
- IOP measure.
- Precise manifest refraction, uncorrected visual acuity and best corrected visual acuity by snellen's chart.
- Standard keratometry to confirm diopters of corneal astigmatism.
- Corneal Tomography (Pentacam).
Surgical procedures:
LRIs are performed using topical anesthesia. Patients are instructed to fixate on the microscope light. Before surgery, the steep meridian was identified with a marker dyed with methylene blue with the patient sitting up right. A diamond knife is set at a depth of 0.600 mm to 0.650 mm based on the peripheral pachymetric readings over the area of intended incision. The goal was a maximum reduction in astigmatism without overcorrection in with-the rule cases and with little overcorrection in against the rule cases. In the case of an overcorrection, the LRI can be sutured without creating any irregular astigmatism.
Performing femtosecond laser-guided astigmatic keratotomy requires the parameters of length, position, depth and distance from the visual axis where the incisions will be created. The depth of our incisions is 85% of the corneal pachymetry in the area of the incision. We have set our distance from the visual axis at 8 mm. This information is all downloaded onto the femtosecond laser. Then, we begin the surgical procedure by docking the laser onto the cornea. An overlay of the incisions is then visible on the surgical screen. After treatment, we bring the patient to the operating microscope and open the incisions with a Sinskey hook. By using low energy, the incisions do not have significant effect until they are opened.
- Conditions
- Corneal Astigmatism
- Being tested
- limbal relaxing incisions, astigmatic keratotomy
- Medical subject headings
- Astigmatism
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
limbal relaxing incisionsProcedure or surgery
Manually performed surgical procedure
astigmatic keratotomyProcedure or surgery
femtosecond laser guided surgical procedure
| Study group | Role | What they receive |
|---|---|---|
| limbal relaxing incisions | Active comparator | Manually performed limbal relaxing incisions Receives: Procedure: limbal relaxing incisions |
| astigmatic keratotomy | Active comparator | femtosecond laser-guided astigmatic keratotomy Receives: Procedure: astigmatic keratotomy |
What is being measured
The primary outcome is the main question the study is designed to answer.
Keratometric reading
measured by Corneal Tomography (Pentacam)
Measured: 1 week
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted29 Aug 2017
- Study start21 Mar 2018
- Primary completion15 Jan 2022
- Study completion15 Jan 2022
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Corneal AstigmatismStudies of the same condition, open and under way.
- More trials run by Assiut UniversityThe sponsor's other registered studies.
- 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 N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Enrolment
- 90 participants (actual)
Sponsor and investigators
- Lead sponsor
- Assiut University
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Ashraf Rashwan, Assiut University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT03264534
- Sponsor's protocol ID
- 17200119
- Status last verified
- Nov 2023
- First submitted
- 24 Aug 2017
- Last updated
- 22 Nov 2023
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided: There is a possibility of using these data in another related study so i am not sure about the time of sharing the individual participant data
Study at a glance
From the registry record, last updated by the sponsor on 22 Nov 2023. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Manually Performed Limbal Relaxing Incisions vs Femtosecond Laser-guided Astigmatic Keratotomy for Correction of Corneal Astigmatism After Phacoemulsification
- ClinicalTrials.gov ID
- NCT03264534
- Acronym / sponsor ID
- 17200119
- Conditions
- Corneal Astigmatism
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 90 participants (actual)
- Lead sponsor
- Assiut UniversityUniversity, hospital or other
- Study start
- 21 Mar 2018 (actual)
- Primary completion
- 15 Jan 2022 (actual)
- Study completion
- 15 Jan 2022 (actual)
- First posted
- 29 Aug 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.
Astigmatic keratotomy (AK) is used to treat numerous refractive disorders, including congenital astigmatism, residual corneal astigmatism at the time of or following cataract surgery, post-traumatic astigmatism, and astigmatism after corneal transplantation.
Within the past few years, much consideration has been given to an evolutionary variant of the procedure, the limbal relaxing incision (LRI). By moving the incision farther to the periphery, cataract surgeons can safely and predictably remediate mild to moderate amounts of regular astigmatism at the time of cataract surgery by performing this incisional technique.
Recent technological developments have shifted ophthalmologist's attention from manually created LRIs and astigmatic keratotomy procedures to femtosecond laser-guided procedures. Femtosecond lasers offer superior incisional accuracy and reproducibility coupled with minimal effects on collateral tissues, achieving levels of safety and reproducibility exceeding those of mechanical techniques. A major clinical application of the femtosecond laser is for creating arcuate incisions that have a precise and accurate length, depth, angular position, and optical zone.
Detailed description
Pre-operative evaluation:
- Close examination of the peripheral cornea by slit lamb, particularly in the areas where the incisions will be placed.
- Fundus examination to exclude other causes of diminution of vision.
- IOP measure.
- Precise manifest refraction, uncorrected visual acuity and best corrected visual acuity by snellen's chart.
- Standard keratometry to confirm diopters of corneal astigmatism.
- Corneal Tomography (Pentacam).
Surgical procedures:
LRIs are performed using topical anesthesia. Patients are instructed to fixate on the microscope light. Before surgery, the steep meridian was identified with a marker dyed with methylene blue with the patient sitting up right. A diamond knife is set at a depth of 0.600 mm to 0.650 mm based on the peripheral pachymetric readings over the area of intended incision. The goal was a maximum reduction in astigmatism without overcorrection in with-the rule cases and with little overcorrection in against the rule cases. In the case of an overcorrection, the LRI can be sutured without creating any irregular astigmatism.
Performing femtosecond laser-guided astigmatic keratotomy requires the parameters of length, position, depth and distance from the visual axis where the incisions will be created. The depth of our incisions is 85% of the corneal pachymetry in the area of the incision. We have set our distance from the visual axis at 8 mm. This information is all downloaded onto the femtosecond laser. Then, we begin the surgical procedure by docking the laser onto the cornea. An overlay of the incisions is then visible on the surgical screen. After treatment, we bring the patient to the operating microscope and open the incisions with a Sinskey hook. By using low energy, the incisions do not have significant effect until they are opened.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| limbal relaxing incisions | Active comparator | Procedure: limbal relaxing incisionsManually performed limbal relaxing incisions |
| astigmatic keratotomy | Active comparator | Procedure: astigmatic keratotomyfemtosecond laser-guided astigmatic keratotomy |
Who may qualify
- Ages
- 21 to 65 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (3 listed)
- patients who have undergo phacoemulsification.
- Clear cornea.
- Astigmatism from 1 diopter up to 4 diopters
Key exclusion criteria (5 listed)
- corneal opacity.
- History of corneal surgery.
- Thin cornea.
- Other cause of diminution of vision rather than corneal astigmatism (eg: optic disc atrophy \& maculopathy).
- Astigmatism less than 1 diopter and more than 4 diopters.
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 |
|---|---|---|
| limbal relaxing incisionsManually performed surgical procedure | Procedure or surgery | limbal relaxing incisions |
| astigmatic keratotomyfemtosecond laser guided surgical procedure | Procedure or surgery | astigmatic keratotomy |
Primary outcome
Keratometric reading
Time frame: 1 week
measured by Corneal Tomography (Pentacam)
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 22 Nov 2023.
- Individual participant dataSharing planned: Undecided. There is a possibility of using these data in another related study so i am not sure about the time of sharing the individual participant data
Related trials for Corneal Astigmatism
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Corneal Biomechanics and Surgically Induced Astigmatism in Pseudoexfoliation Syndrome
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Active, not recruiting
Influence of Implantation Technique on Rotational Stability of a Frosted-Haptic Toric Intraocular Lens: A Prospective Contralateral-Eye Study
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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.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing limbal relaxing incisions and astigmatic keratotomy in people with Corneal Astigmatism, run by Assiut University at 1 site in Egypt.
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 3 inclusion and 5 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 22 Nov 2023. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Egypt. Whether a site is taking part right now should be confirmed with that site. See every site.
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?
Keratometric reading (time frame: 1 week). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
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 22 Nov 2023.