- ICH GCP
- US Clinical Trials Registry
- Klinisk forsøg NCT01893671
Corneal Power, Astigmatism, and Aberration Changes After LASIK
4. april 2018 opdateret af: David Huang, Oregon Health and Science University
Observational Study of Corneal Power, Astigmatism, and Aberration Changes After LASIK
The primary goal of the study is to determine if Optical Coherence Tomography (OCT) measurement of corneal power and astigmatism is more accurate than conventional Placido-ring corneal topography.
A second goal is to evaluate OCT-based epithelial thickness mapping.
The postoperative epithelial thickness variation will be used to calculate refractive effects and calibrate the smoothing parameter in the mathematical model relating corneal mean curvature and epithelial thickness.
A third goal is to assess the repeatability of OCT measurements.
A fourth goal is to develop a method of estimating the focusing power, astigmatism, and HOA of the crystalline lens based on measurements of the lens' anterior and posterior capsular topographies and positions with the ultrahigh-speed MIT OCT prototype.
Studieoversigt
Status
Afsluttet
Detaljeret beskrivelse
A prospective observational study on refraction and HOA changes after LASIK will be conducted at OHSU and Baylor.
We will enroll 50 subjects undergoing routine LASIK for the correction of myopia or hyperopia.
The Optovue anterior segment OCT prototype will be used to measure corneal power, astigmatism, HOA, and epithelial thickness map.
The ultrahigh-speed MIT OCT prototypes will also be used when they become available.
A comprehensive eye examination will be performed preoperatively.
OCT scan, manifest refraction, visual acuity, Placido-ring corneal topography, slit scanning/Scheimpflug camera, and wavefront measurements will be acquired preoperatively and 3-6 months after the surgery.
The LASIK-induced refraction and wavefront HOA changes will be used as the reference standard to evaluate the accuracy of OCT-measured corneal power, astigmatism, and HOA changes.
The primary goal of the study is to determine if OCT measurement of corneal power and astigmatism is more accurate than conventional Placido-ring corneal topography.
A second goal is to evaluate OCT-based epithelial thickness mapping.
The postoperative epithelial thickness variation will be used to calculate refractive effects and calibrate the smoothing parameter in the mathematical model relating corneal mean curvature and epithelial thickness.
A third goal is to assess the repeatability of OCT measurements.
A fourth goal is to develop a method of estimating the focusing power, astigmatism, and HOA of the crystalline lens based on measurements of the lens' anterior and posterior capsular topographies and positions with the ultrahigh-speed MIT OCT prototype.
The reference standard for lens focusing power and astigmatism will be based on a Gaussian optics model that takes as inputs manifest refraction, crystalline lens position, axial eye length, and OCT corneal power and astigmatism measurements.
The reference standard for lens HOA will be the difference between wavefront HOA and corneal HOA.
For each eye, the best-fit effective index of the lens will be found so that OCT measurements will match the reference data.
Although the lens index is likely to be higher centrally than peripherally, this secondary perturbation will be accounted for by a posterior shift of the posterior lens capsule in OCT images, due to the fact that apparent distances in OCT images is a product of physical distance and optical group index.
Thus HOA due to index variation in the lens would translate to unevenness in the posterior capsule surface that could be measured with OCT.
Undersøgelsestype
Observationel
Tilmelding (Faktiske)
22
Kontakter og lokationer
Dette afsnit indeholder kontaktoplysninger for dem, der udfører undersøgelsen, og oplysninger om, hvor denne undersøgelse udføres.
Studiesteder
-
-
Oregon
-
Portland, Oregon, Forenede Stater, 97239
- Oregon Health & Science University
-
-
Deltagelseskriterier
Forskere leder efter personer, der passer til en bestemt beskrivelse, kaldet berettigelseskriterier. Nogle eksempler på disse kriterier er en persons generelle helbredstilstand eller tidligere behandlinger.
Berettigelseskriterier
Aldre berettiget til at studere
18 år og ældre (Voksen, Ældre voksen)
Tager imod sunde frivillige
Ingen
Køn, der er berettiget til at studere
Alle
Prøveudtagningsmetode
Ikke-sandsynlighedsprøve
Studiebefolkning
Subjects undergoing routine LASIK for the correction of myopia or hyperopia with or without astigmatism
Beskrivelse
Inclusion Criteria:
1. Patients who qualify for primary LASIK for either myopia or hyperopia, with or without astigmatism.
Exclusion Criteria:
- Inability to give informed consent.
- Inability to maintain stable fixation for OCT imaging.
- Inability to commit to required visits to complete the study.
- Eyes with concurrent cataract, retinal diseases, glaucoma, or other eye conditions that may limit the visual outcome after surgery
Studieplan
Dette afsnit indeholder detaljer om studieplanen, herunder hvordan undersøgelsen er designet, og hvad undersøgelsen måler.
Hvordan er undersøgelsen tilrettelagt?
Design detaljer
- Observationsmodeller: Kun etui
- Tidsperspektiver: Fremadrettet
Kohorter og interventioner
Gruppe / kohorte |
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LASIK
Subjects undergoing routine LASIK for the correction of myopia or hyperopia.
|
Hvad måler undersøgelsen?
Primære resultatmål
Resultatmål |
Foranstaltningsbeskrivelse |
Tidsramme |
---|---|---|
OCT measurement of corneal power and astigmatism vs Placido-ring
Tidsramme: 5 year
|
primary goal of the study is to determine if OCT measurement of corneal power and astigmatism is more accurate than conventional Placido-ring corneal topography
|
5 year
|
Sekundære resultatmål
Resultatmål |
Foranstaltningsbeskrivelse |
Tidsramme |
---|---|---|
An evaluation of OCT-based epithelial thickness mapping
Tidsramme: 5 year
|
The postoperative epithelial thickness variation will be used to calculate refractive effects and calibrate the smoothing parameter in the mathematical model relating corneal mean curvature and epithelial thickness.
|
5 year
|
OCT measurements repeatability
Tidsramme: 5 year
|
An assessment of the repeatability of OCT measurements
|
5 year
|
The Development of a method of estimating the focusing power, astigmatism, and HOA of the crystalline lens
Tidsramme: 5 year
|
The Development of a method of estimating the focusing power, astigmatism, and HOA of the crystalline lens based on measurements of the lens' anterior and posterior capsular topographies and positions with the ultrahigh-speed MIT OCT prototype.
|
5 year
|
Samarbejdspartnere og efterforskere
Det er her, du vil finde personer og organisationer, der er involveret i denne undersøgelse.
Samarbejdspartnere
Efterforskere
- Ledende efterforsker: David Huang, MD, PhD, Oregon Health & Science Universtiy
Datoer for undersøgelser
Disse datoer sporer fremskridtene for indsendelser af undersøgelsesrekord og resumeresultater til ClinicalTrials.gov. Studieregistreringer og rapporterede resultater gennemgås af National Library of Medicine (NLM) for at sikre, at de opfylder specifikke kvalitetskontrolstandarder, før de offentliggøres på den offentlige hjemmeside.
Studer store datoer
Studiestart
1. januar 2011
Primær færdiggørelse (Faktiske)
31. august 2017
Studieafslutning (Faktiske)
31. august 2017
Datoer for studieregistrering
Først indsendt
2. juli 2013
Først indsendt, der opfyldte QC-kriterier
2. juli 2013
Først opslået (Skøn)
9. juli 2013
Opdateringer af undersøgelsesjournaler
Sidste opdatering sendt (Faktiske)
5. april 2018
Sidste opdatering indsendt, der opfyldte kvalitetskontrolkriterier
4. april 2018
Sidst verificeret
1. april 2018
Mere information
Begreber relateret til denne undersøgelse
Yderligere relevante MeSH-vilkår
Andre undersøgelses-id-numre
- OHSU IRB#6612
- R01EY018184 (U.S. NIH-bevilling/kontrakt)
Lægemiddel- og udstyrsoplysninger, undersøgelsesdokumenter
Studerer et amerikansk FDA-reguleret lægemiddelprodukt
Ingen
Studerer et amerikansk FDA-reguleret enhedsprodukt
Ingen
produkt fremstillet i og eksporteret fra U.S.A.
Ingen
Disse oplysninger blev hentet direkte fra webstedet clinicaltrials.gov uden ændringer. Hvis du har nogen anmodninger om at ændre, fjerne eller opdatere dine undersøgelsesoplysninger, bedes du kontakte register@clinicaltrials.gov. Så snart en ændring er implementeret på clinicaltrials.gov, vil denne også blive opdateret automatisk på vores hjemmeside .