Reproducibility of Corneal Graft Thickness measurements with COLGATE in patients who have undergone DSAEK (Descemet Stripping Automated Endothelial Keratoplasty)

BackgroundThe CorneaL GrAft Thickness Evaluation (COLGATE) system was recently developed to facilitate the evaluation of corneal graft thickness from OCT images. Graft thickness measurement can be a surrogate indicator for detecting graft failure or success. The purpose of this study was to determine the reproducibility of the COLGATE system in measuring DSAEK graft area between two observers.MethodsThis was a prospective case series in which 50 anterior segment OCT images of patients who had undergone DSAEK in either eye were analysed. Two observers (MW, AC) independently obtained the image analysis for the graft area using both semi automated and automated method. One week later, each observer repeated the analysis for the same set of images. Bland-Altman analysis was performed to analyze inter and intra observer agreement.ResultsThere was strong intraobserver correlation between the 2 semi automated readings obtained by both observers. (r = 0.936 and r = 0.962). Intraobserver ICC for observer 1 was 0.936 (95% CI 0.890 to 0.963) and 0.967 (95% CI 0.942 to 0.981) for observer 2. Likewise, there was also strong interobserver correlation (r = 0.913 and r = 0.969). The interobserver ICC for the first measurements was 0.911 (95% CI 0.849 to 0.949) and 0.968 (95% CI 0.945 to 0.982) for the second. There was statistical difference between the automatic and the semi automated readings for both observers (p = 0.006, p = 0.003). The automatic readings gave consistently higher values than the semi automated readings especially in thin grafts.ConclusionThe analysis from the COLGATE programme can be reproducible between different observers. Care must be taken when interpreting the automated analysis as they tend to over estimate measurements.

[1]  R. H. Wijdh,et al.  A Technique to Excise the Descemet Membrane From a Recipient Cornea (Descemetorhexis) , 2004, Cornea.

[2]  J. Mehta,et al.  Biometry of the cornea and anterior chamber in chinese eyes: an anterior segment optical coherence tomography study. , 2010, Investigative ophthalmology & visual science.

[3]  Terry Kim,et al.  Refractive Change After Descemet Stripping Automated Endothelial Keratoplasty Surgery and Its Correlation With Graft Thickness and Diameter , 2009, Cornea.

[4]  Dariusz Dobrowolski,et al.  Anterior segment imaging: Fourier‐domain optical coherence tomography versus time‐domain optical coherence tomography , 2009, Journal of cataract and refractive surgery.

[5]  J. Mehta,et al.  Laser in situ keratomileusis flap measurements: Comparison between observers and between spectral‐domain and time‐domain anterior segment optical coherence tomography , 2011, Journal of cataract and refractive surgery.

[6]  R. Weinreb,et al.  Anterior chamber angle imaging with optical coherence tomography , 2011, Eye.

[7]  Tin Aung,et al.  Diagnostic performance of anterior chamber angle measurements for detecting eyes with narrow angles: an anterior segment OCT study. , 2010, Archives of ophthalmology.

[8]  John F. Canny,et al.  A Computational Approach to Edge Detection , 1986, IEEE Transactions on Pattern Analysis and Machine Intelligence.

[9]  M. Moshirfar,et al.  Corneal profile analysis after Descemet stripping endothelial keratoplasty and its relationship to postoperative hyperopic shift , 2008, Journal of cataract and refractive surgery.

[10]  Jiang Liu,et al.  Corneal graft detection for Descemet's Stripping Automated Endothelial Keratoplasty using Optical Coherence Tomography , 2010, 2010 Annual International Conference of the IEEE Engineering in Medicine and Biology.

[11]  F. Verbraak,et al.  Thickness Measurements of Donor Posterior Disks After Descemet Stripping Endothelial Keratoplasty With Anterior Segment Optical Coherence Tomography , 2009, Cornea.

[12]  Ronald H Silverman,et al.  High‐resolution ultrasound imaging of the eye – a review , 2009, Clinical & experimental ophthalmology.

[13]  R. Ritch,et al.  The use of postoperative slit-lamp optical coherence tomography to predict primary failure in descemet stripping automated endothelial keratoplasty. , 2009, American journal of ophthalmology.

[14]  Yan Li,et al.  A longitudinal study of LASIK flap and stromal thickness with high-speed optical coherence tomography. , 2007, Ophthalmology.

[15]  V. Scorcia,et al.  Pentacam assessment of posterior lamellar grafts to explain hyperopization after Descemet's stripping automated endothelial keratoplasty. , 2009, Ophthalmology.