Noninvasive assessment of the hydration gradient across the cornea using confocal raman spectroscopy

Noël J C Bauer, James P. Wicksted, Franciscus H M Jongsma, Wayne F. March, Fred Hendrikse, Massoud Motamedi

Research output: Contribution to journalArticle

59 Citations (Scopus)

Abstract

PURPOSE. The feasibility of Raman spectroscopy for the noninvasive assessment of axial corneal hydration was investigated. METHODS. A scanning confocal Raman spectroscopy system, with an axial resolution of 50 μm, was used to assess noninvasively the water (OH-bond) to protein (CH-bond) ratio as a measure of the hydration in collagen-based phantom media and rabbit corneas. RESULTS. Raman spectra with high signal-to-noise ratios were obtained under in vitro and in vivo conditions within a range of corneal hydration (H = 0.0-8.3 mg water/mg dry wt). The Raman intensity ratio OH/CH showed a strong correlation with the hydration of the phantom medium (R2 > 0.99) and the rabbit corneas (R2 > 0.95). A degree of reproducibility was seen in measurements performed at a specific depth within the cornea (SD = 1.2%-2.7%). Quantitatively, the spatially resolved corneal water content, as assessed with our method, showed an increasing gradient from the anterior to the posterior region, with a difference of approximately 0.9. Significant qualitative differences in the axial hydration gradient were observed between the in vitro and in vivo situation, caused by the presence of an intact tear- film in vivo. Characterization of the axial corneal hydration using Raman spectroscopy provided a reliable estimation of total corneal hydration compared with conventional measurements using pachymetry and lyophilization. CONCLUSIONS. The proposed noninvasive confocal Raman spectroscopic technique has the potential to assess the axial corneal water gradient with a degree of sensitivity and reproducibility.

Original languageEnglish (US)
Pages (from-to)831-835
Number of pages5
JournalInvestigative Ophthalmology and Visual Science
Volume39
Issue number5
StatePublished - Apr 1998

Fingerprint

Raman Spectrum Analysis
Cornea
Water
Rabbits
Freeze Drying
Signal-To-Noise Ratio
Tears
Collagen
Proteins
In Vitro Techniques

ASJC Scopus subject areas

  • Ophthalmology

Cite this

Bauer, N. J. C., Wicksted, J. P., Jongsma, F. H. M., March, W. F., Hendrikse, F., & Motamedi, M. (1998). Noninvasive assessment of the hydration gradient across the cornea using confocal raman spectroscopy. Investigative Ophthalmology and Visual Science, 39(5), 831-835.

Noninvasive assessment of the hydration gradient across the cornea using confocal raman spectroscopy. / Bauer, Noël J C; Wicksted, James P.; Jongsma, Franciscus H M; March, Wayne F.; Hendrikse, Fred; Motamedi, Massoud.

In: Investigative Ophthalmology and Visual Science, Vol. 39, No. 5, 04.1998, p. 831-835.

Research output: Contribution to journalArticle

Bauer, Noël J C ; Wicksted, James P. ; Jongsma, Franciscus H M ; March, Wayne F. ; Hendrikse, Fred ; Motamedi, Massoud. / Noninvasive assessment of the hydration gradient across the cornea using confocal raman spectroscopy. In: Investigative Ophthalmology and Visual Science. 1998 ; Vol. 39, No. 5. pp. 831-835.
@article{90868134538e4fa4bd6c2e625e2c5cee,
title = "Noninvasive assessment of the hydration gradient across the cornea using confocal raman spectroscopy",
abstract = "PURPOSE. The feasibility of Raman spectroscopy for the noninvasive assessment of axial corneal hydration was investigated. METHODS. A scanning confocal Raman spectroscopy system, with an axial resolution of 50 μm, was used to assess noninvasively the water (OH-bond) to protein (CH-bond) ratio as a measure of the hydration in collagen-based phantom media and rabbit corneas. RESULTS. Raman spectra with high signal-to-noise ratios were obtained under in vitro and in vivo conditions within a range of corneal hydration (H = 0.0-8.3 mg water/mg dry wt). The Raman intensity ratio OH/CH showed a strong correlation with the hydration of the phantom medium (R2 > 0.99) and the rabbit corneas (R2 > 0.95). A degree of reproducibility was seen in measurements performed at a specific depth within the cornea (SD = 1.2{\%}-2.7{\%}). Quantitatively, the spatially resolved corneal water content, as assessed with our method, showed an increasing gradient from the anterior to the posterior region, with a difference of approximately 0.9. Significant qualitative differences in the axial hydration gradient were observed between the in vitro and in vivo situation, caused by the presence of an intact tear- film in vivo. Characterization of the axial corneal hydration using Raman spectroscopy provided a reliable estimation of total corneal hydration compared with conventional measurements using pachymetry and lyophilization. CONCLUSIONS. The proposed noninvasive confocal Raman spectroscopic technique has the potential to assess the axial corneal water gradient with a degree of sensitivity and reproducibility.",
author = "Bauer, {No{\"e}l J C} and Wicksted, {James P.} and Jongsma, {Franciscus H M} and March, {Wayne F.} and Fred Hendrikse and Massoud Motamedi",
year = "1998",
month = "4",
language = "English (US)",
volume = "39",
pages = "831--835",
journal = "Investigative Ophthalmology and Visual Science",
issn = "0146-0404",
publisher = "Association for Research in Vision and Ophthalmology Inc.",
number = "5",

}

TY - JOUR

T1 - Noninvasive assessment of the hydration gradient across the cornea using confocal raman spectroscopy

AU - Bauer, Noël J C

AU - Wicksted, James P.

AU - Jongsma, Franciscus H M

AU - March, Wayne F.

AU - Hendrikse, Fred

AU - Motamedi, Massoud

PY - 1998/4

Y1 - 1998/4

N2 - PURPOSE. The feasibility of Raman spectroscopy for the noninvasive assessment of axial corneal hydration was investigated. METHODS. A scanning confocal Raman spectroscopy system, with an axial resolution of 50 μm, was used to assess noninvasively the water (OH-bond) to protein (CH-bond) ratio as a measure of the hydration in collagen-based phantom media and rabbit corneas. RESULTS. Raman spectra with high signal-to-noise ratios were obtained under in vitro and in vivo conditions within a range of corneal hydration (H = 0.0-8.3 mg water/mg dry wt). The Raman intensity ratio OH/CH showed a strong correlation with the hydration of the phantom medium (R2 > 0.99) and the rabbit corneas (R2 > 0.95). A degree of reproducibility was seen in measurements performed at a specific depth within the cornea (SD = 1.2%-2.7%). Quantitatively, the spatially resolved corneal water content, as assessed with our method, showed an increasing gradient from the anterior to the posterior region, with a difference of approximately 0.9. Significant qualitative differences in the axial hydration gradient were observed between the in vitro and in vivo situation, caused by the presence of an intact tear- film in vivo. Characterization of the axial corneal hydration using Raman spectroscopy provided a reliable estimation of total corneal hydration compared with conventional measurements using pachymetry and lyophilization. CONCLUSIONS. The proposed noninvasive confocal Raman spectroscopic technique has the potential to assess the axial corneal water gradient with a degree of sensitivity and reproducibility.

AB - PURPOSE. The feasibility of Raman spectroscopy for the noninvasive assessment of axial corneal hydration was investigated. METHODS. A scanning confocal Raman spectroscopy system, with an axial resolution of 50 μm, was used to assess noninvasively the water (OH-bond) to protein (CH-bond) ratio as a measure of the hydration in collagen-based phantom media and rabbit corneas. RESULTS. Raman spectra with high signal-to-noise ratios were obtained under in vitro and in vivo conditions within a range of corneal hydration (H = 0.0-8.3 mg water/mg dry wt). The Raman intensity ratio OH/CH showed a strong correlation with the hydration of the phantom medium (R2 > 0.99) and the rabbit corneas (R2 > 0.95). A degree of reproducibility was seen in measurements performed at a specific depth within the cornea (SD = 1.2%-2.7%). Quantitatively, the spatially resolved corneal water content, as assessed with our method, showed an increasing gradient from the anterior to the posterior region, with a difference of approximately 0.9. Significant qualitative differences in the axial hydration gradient were observed between the in vitro and in vivo situation, caused by the presence of an intact tear- film in vivo. Characterization of the axial corneal hydration using Raman spectroscopy provided a reliable estimation of total corneal hydration compared with conventional measurements using pachymetry and lyophilization. CONCLUSIONS. The proposed noninvasive confocal Raman spectroscopic technique has the potential to assess the axial corneal water gradient with a degree of sensitivity and reproducibility.

UR - http://www.scopus.com/inward/record.url?scp=0031977706&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0031977706&partnerID=8YFLogxK

M3 - Article

C2 - 9538892

AN - SCOPUS:0031977706

VL - 39

SP - 831

EP - 835

JO - Investigative Ophthalmology and Visual Science

JF - Investigative Ophthalmology and Visual Science

SN - 0146-0404

IS - 5

ER -