Swelling of the human cornea revealed by high-speed, ultrahigh-resolution optical coherence tomography.
OBJECTIVE
To evaluate the change in thickness of the anterior, stromal, and posterior corneal laminae in response to hypoxia-induced corneal swelling, by means of ultrahigh-resolution optical coherence tomography (UHR-OCT).


METHODS
A UHR-OCT system, operating in the 1060-nm range, was used to acquire in vivo cross-sectional images of human cornea with a 3.2x10-microm (axial x lateral) resolution in corneal tissue. Corneal edema was induced by inserting a thick, positive-powered, soft contact lens, over which the eye was closed and patched for 3 hours. Tomograms were acquired from eight non-contact-lens wearers. Baseline images were obtained before inducing corneal edema, immediately after removal of the patch and the lens, and then every 15 minutes for approximately 2 hours. All images were postprocessed with a segmentation algorithm to identify the laminae visible in the image. The apical thickness of the laminae (epithelium [EPI], epithelial-Bowman's membrane [Ep-BM] complex, stroma, and endothelial-Descemet's membrane [En-DM] complex) were determined at each time interval.


RESULTS
There was an interaction between time after removal of the hypoxic stimulus and deswelling of the layers (RM-ANOVA; P<0.001). The epithelial and stromal thickness reduced significantly with time (P=0.001; P<0.001, respectively), whereas the Ep-BM and En-DM complexes did not (P>0.50). All layers except the En-DM complex exhibited a biphasic pattern of recovery.


CONCLUSIONS
UHR-OCT showed regional differences in swelling due to hypoxic provocation. On removal of the hypoxic stimulus, the rate of recovery varied between layers, and all layers except the En-DM complex exhibited a biphasic recovery.
Hutchings
Natalie
N
School of Optometry, Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario, Canada. nhutchin@uwaterloo.ca
Simpson
Trefford L
TL
Hyun
Chulho
C
Moayed
Alireza A
AA
Hariri
Sepideh
S
Sorbara
Luigina
L
Bizheva
Kostadinka
K
D000328:Adult; D000465:Algorithms; D000873:Anthracenes; D003263:Contact Lenses, Hydrophilic / Q000009:adverse effects; D015715:Corneal Edema / Q000209:etiology / Q000378:metabolism / Q000473:pathology*; D003886:Descemet Membrane / Q000378:metabolism / Q000473:pathology*; D005260:Female; D006801:Humans; D000860:Hypoxia / Q000150:complications / Q000378:metabolism / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D020127:Recovery of Function; D041623:Tomography, Optical Coherence / Q000295:instrumentation* / Q000379:methods*; D055815:Young Adult
C546739:AnOV compound; D000873:Anthracenes