ブリルアン顕微鏡を用いた角膜生体力学解析
The objective of this study is to measure the Brillouin biomechanical properties in keratoconic corneas and characterize biomechanical alterations that occur after corneal procedures that inherently strengthen or weaken the cornea by evaluating the change in Brillouin metrics before and after treatments.
調査の概要
詳細な説明
Surgical correction of myopia and keratoconus identification/management are separate but tightly intertwined issues of major significance. For both, there is an unmet need for direct measurements to evaluate corneal stiffness (i.e. its resistance to deformation). The prevalence of myopia is expected to double, affecting more than 50% of the US population, by 2050. Laser in situ keratomileusis (LASIK) is one of the most popular and successful surgeries in the world and compares favorably to long-term contact lens wear use for myopia correction. However, only ~10% of eligible patients undergo LASIK currently; the others cite safety concerns as a major factor in their decision. The primary risk for poor refractive surgery outcomes is biomechanical failure due to unidentified (subclinical) ectasia (i.e. keratoconus). Patients presenting for LASIK evaluation with atypical, suspicious corneal curvature but with undetermined true risk represent the leading reason for surgery screening failures. This results in good candidates being denied surgery, while up to 10% of truly poor candidates are still missed using current screening algorithms.
Keratoconus is up to 10 times more prevalent than the previously reported 1/2000 figure. Corneal cross-linking (CXL) is now FDA approved in the US for keratoconus treatment and is effective at stiffening the cornea and halting ectasia progression. Early identification of keratoconus is critical, but current tests in the clinic are morphological, not biomechanical, and therefore do not allow a definitive diagnosis at the earliest stages resulting in vision loss before CXL treatment is initiated. Thus, the need for accurate identification of subclinical ectasia has never been greater.
In the past years, newly developed technology, Brillouin microscopy, has emerged as the most promising tool to address this clinical need. This study will systemically address the critical gap in current knowledge by linking Brillouin mapping of corneal biomechanical alterations to abnormal morphological behavior and testing the findings in conditions where corneal biomechanics are abruptly altered, by: 1) weakening with refractive surgery procedures, and 2) strengthening through corneal cross-linking.
It is anticipated that a clinical tool assessing the mechanical state of the cornea will improve early diagnosis and management of keratoconus as well as refractive surgery planning. Ultimately, this will lead to predictive models where Brillouin measurements could be an accurate predictor of postoperative outcomes and thus aid in developing individualized surgical parameters.
研究の種類
入学 (推定)
連絡先と場所
研究場所
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Ohio
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Cleveland、Ohio、アメリカ、44195
- Cleveland Clinic Cole Eye Institute
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参加基準
適格基準
就学可能な年齢
健康ボランティアの受け入れ
受講資格のある性別
サンプリング方法
調査対象母集団
Group 1: Patients with normal corneas Group 2: Patients with keratoconus Group 3: Patients with normal corneas undergoing LASIK Group 4: Patients with normal corneas undergoing PRK Group 5: Patients with normal corneas undergoing SMILE Group 6: Patients with keratoconus undergoing CXL
説明
Inclusion Criteria:
- patients aged 18-60 with keratoconus
- patients aged 18-60 with normal corneas,
- patients aged 18-60 undergoing refractive surgery (LASIK, PRK, SMILE)
- patients aged 18-60 with keratoconus undergoing CXL
Exclusion Criteria:
- outside age range
- history of previous ocular surgeries
- unable to cooperate for the Brillouin microscopic examination
- unable to provide informed consent
研究計画
研究はどのように設計されていますか？
デザインの詳細
- 観測モデル：CASE_CONTROL
- 時間の展望：CROSS_SECTIONAL
コホートと介入
グループ/コホート |
介入・治療 |
|---|---|
|
1: Normal Controls
Patients with normal corneas without any prior surgery to serve as the control group |
The Brillouin clinical instrument is comprised of three parts: a human interface, a laser-scanning confocal microscope, and an etalon-based spectrometer. The human interface is a modified ophthalmic slit-lamp instrument with chin support and headrest. The light source is a single longitudinal mode CW laser at 780 nm. A polarizing beam splitter and quarter-wave plate assembly sends the laser beam to the human interface. To focus light into the eye, a long-working distance microscope objective is used. Brillouin scattered light from the eye is collected with a single-mode optical fiber. For spectral analysis, a two-stage VIPA-etalon spectrometer configured with the cross-axis cascade principle and the spectrum is measured on a EM-CCD camera. |
|
2 Keratoconus
Patients with various stages of keratoconus |
The Brillouin clinical instrument is comprised of three parts: a human interface, a laser-scanning confocal microscope, and an etalon-based spectrometer. The human interface is a modified ophthalmic slit-lamp instrument with chin support and headrest. The light source is a single longitudinal mode CW laser at 780 nm. A polarizing beam splitter and quarter-wave plate assembly sends the laser beam to the human interface. To focus light into the eye, a long-working distance microscope objective is used. Brillouin scattered light from the eye is collected with a single-mode optical fiber. For spectral analysis, a two-stage VIPA-etalon spectrometer configured with the cross-axis cascade principle and the spectrum is measured on a EM-CCD camera. |
|
3: LASIK
Patients with normal corneas who are undergoing laser in situ keratomileusis (LASIK) |
The Brillouin clinical instrument is comprised of three parts: a human interface, a laser-scanning confocal microscope, and an etalon-based spectrometer. The human interface is a modified ophthalmic slit-lamp instrument with chin support and headrest. The light source is a single longitudinal mode CW laser at 780 nm. A polarizing beam splitter and quarter-wave plate assembly sends the laser beam to the human interface. To focus light into the eye, a long-working distance microscope objective is used. Brillouin scattered light from the eye is collected with a single-mode optical fiber. For spectral analysis, a two-stage VIPA-etalon spectrometer configured with the cross-axis cascade principle and the spectrum is measured on a EM-CCD camera. |
|
Group 4: PRK
Patients with normal corneas who are undergoing photorefractive keratectomy (PRK) |
The Brillouin clinical instrument is comprised of three parts: a human interface, a laser-scanning confocal microscope, and an etalon-based spectrometer. The human interface is a modified ophthalmic slit-lamp instrument with chin support and headrest. The light source is a single longitudinal mode CW laser at 780 nm. A polarizing beam splitter and quarter-wave plate assembly sends the laser beam to the human interface. To focus light into the eye, a long-working distance microscope objective is used. Brillouin scattered light from the eye is collected with a single-mode optical fiber. For spectral analysis, a two-stage VIPA-etalon spectrometer configured with the cross-axis cascade principle and the spectrum is measured on a EM-CCD camera. |
|
5: SMILE
Patients with normal corneas who are undergoing small incision lenticular extraction (SMILE) |
The Brillouin clinical instrument is comprised of three parts: a human interface, a laser-scanning confocal microscope, and an etalon-based spectrometer. The human interface is a modified ophthalmic slit-lamp instrument with chin support and headrest. The light source is a single longitudinal mode CW laser at 780 nm. A polarizing beam splitter and quarter-wave plate assembly sends the laser beam to the human interface. To focus light into the eye, a long-working distance microscope objective is used. Brillouin scattered light from the eye is collected with a single-mode optical fiber. For spectral analysis, a two-stage VIPA-etalon spectrometer configured with the cross-axis cascade principle and the spectrum is measured on a EM-CCD camera. |
|
6: CXL
Patients with keratoconus who are undergoing corneal cross-linking (CXL) |
The Brillouin clinical instrument is comprised of three parts: a human interface, a laser-scanning confocal microscope, and an etalon-based spectrometer. The human interface is a modified ophthalmic slit-lamp instrument with chin support and headrest. The light source is a single longitudinal mode CW laser at 780 nm. A polarizing beam splitter and quarter-wave plate assembly sends the laser beam to the human interface. To focus light into the eye, a long-working distance microscope objective is used. Brillouin scattered light from the eye is collected with a single-mode optical fiber. For spectral analysis, a two-stage VIPA-etalon spectrometer configured with the cross-axis cascade principle and the spectrum is measured on a EM-CCD camera. |
この研究は何を測定していますか？
主要な結果の測定
結果測定 |
メジャーの説明 |
時間枠 |
|---|---|---|
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Change in Brillouin Metrics
時間枠：Difference between baseline and 3 months after intervention
|
Brillouin metrics to be evaluated include localized Mean Brillouin modulus measure across the cornea and at each depth of the corneal stroma |
Difference between baseline and 3 months after intervention
|
協力者と研究者
スポンサー
出版物と役立つリンク
一般刊行物
- Zhang H, Roozbahani M, Piccinini AL, Golan O, Hafezi F, Scarcelli G, Randleman JB. Depth-Dependent Reduction of Biomechanical Efficacy of Contact Lens-Assisted Corneal Cross-linking Analyzed by Brillouin Microscopy. J Refract Surg. 2019 Nov 1;35(11):721-728. doi: 10.3928/1081597X-20191004-01.
- Webb JN, Langille E, Hafezi F, Randleman JB, Scarcelli G. Biomechanical Impact of Localized Corneal Cross-linking Beyond the Irradiated Treatment Area. J Refract Surg. 2019 Apr 1;35(4):253-260. doi: 10.3928/1081597X-20190304-01.
- Randleman JB, Su JP, Scarcelli G. Biomechanical Changes After LASIK Flap Creation Combined With Rapid Cross-Linking Measured With Brillouin Microscopy. J Refract Surg. 2017 Jun 1;33(6):408-414. doi: 10.3928/1081597X-20170421-01.
- Scarcelli G, Pineda R, Yun SH. Brillouin optical microscopy for corneal biomechanics. Invest Ophthalmol Vis Sci. 2012 Jan 20;53(1):185-90. doi: 10.1167/iovs.11-8281.
- Scarcelli G, Kling S, Quijano E, Pineda R, Marcos S, Yun SH. Brillouin microscopy of collagen crosslinking: noncontact depth-dependent analysis of corneal elastic modulus. Invest Ophthalmol Vis Sci. 2013 Feb 19;54(2):1418-25. doi: 10.1167/iovs.12-11387.
- Scarcelli G, Besner S, Pineda R, Yun SH. Biomechanical characterization of keratoconus corneas ex vivo with Brillouin microscopy. Invest Ophthalmol Vis Sci. 2014 Jun 17;55(7):4490-5. doi: 10.1167/iovs.14-14450.
- Scarcelli G, Besner S, Pineda R, Kalout P, Yun SH. In vivo biomechanical mapping of normal and keratoconus corneas. JAMA Ophthalmol. 2015 Apr;133(4):480-2. doi: 10.1001/jamaophthalmol.2014.5641. No abstract available.
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研究開始 (実際)
一次修了 (推定)
研究の完了 (推定)
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最初に提出
QC基準を満たした最初の提出物
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