Lack of corneal transparency is a major cause of blindness worldwide. However, means to assess corneal transparency are limited and in current clinical and eye-bank practice usually involve a subjective and qualitative observation of opacities, sometimes with comparison against an arbitrary grading scale, by means of slit-lamp biomicroscopy. To address this unmet need, we have developed a method for corneal transparency assessment based on a new optical data analysis-based approach. Our method allows the objective extraction of quantitative parameters (including the scattering mean-free path, ls, a major indicator of scattering extent and thus of transparency of a medium) based on a physical model of corneal transparency and has been validated by laboratory experiments, using high-resolution, ex-vivo “fullfield” optical coherence tomography (FF-OCT). Here, we apply our algorithm to depth-resolved spectral domain OCT (SD-OCT) images of in-vivo corneas and demonstrate the feasibility of our approach by means of four representative clinical cases. Specifically, we illustrate its potential in discriminating between the four clinical cases and, if applicable, deriving the scattering mean-free path as a quantitative measure of corneal transparency from objective analysis of stromal light backscattering (attenuation of the coherent mean) with SD-OCT. This measure may be related to, or expressed as, Strehl ratio reduction and thus retinal PSF broadening. As such, our approach not only has the potential to supply the demand for an objective means to quantify corneal transparency in the clinical setting, but also to create an association with visual function.
[1]
G. Timberlake,et al.
Corneal light scattering after excimer laser photorefractive keratectomy: the objective measurements of haze.
,
1992,
Refractive & corneal surgery.
[2]
S. Jain,et al.
Objective measurement of corneal light scattering after excimer laser keratectomy.
,
1996,
Ophthalmology.
[3]
C. van de Pol,et al.
Objective assessment of transient corneal haze and its relation to visual performance after photorefractive keratectomy.
,
2001,
American journal of ophthalmology.
[4]
J. Fujimoto,et al.
Optical Coherence Tomography
,
1991
.
[5]
J. Wolffsohn,et al.
Grading of corneal transparency.
,
2004,
Contact lens & anterior eye : the journal of the British Contact Lens Association.
[6]
C. Baudouin,et al.
Evaluation of corneal stromal changes in vivo after laser in situ keratomileusis with confocal microscopy.
,
2001,
Ophthalmology.
[7]
G. Ripandelli,et al.
Optical coherence tomography.
,
1998,
Seminars in ophthalmology.
[8]
G O Waring,et al.
Wound healing after excimer laser keratomileusis (photorefractive keratectomy) in monkeys.
,
1990,
Archives of ophthalmology.