Influence Of Corneal White-To-White (Wtw) In Tomographical Interpretation: A Novel Discovery
Published 2023 - 41st Congress of the ESCRS
Reference: PO0218 | Type: Free paper | DOI: 10.82333/x4hq-cn57
Authors: Himanshu Matalia* 1 , Mathew Francis 2 , Jyoti Matalia 3 , Ansu Ann John 1 , Nandini Chinnappaiah 1 , Rohit Shetty 4 , Abhijit Sinha Roy 2
1Corneal and Refractive Surgery,Narayana Nethralaya,Bangalore,India, 2Imaging, Biomechanics and Mathematical Modelling Solutions,Narayana Nethralaya Foundation,Bangalore,India, 3Pediatric Ophthalmology & Strabismus,Narayana Nethralaya,Bangalore,India, 4Corneal and Refractive Surgery,Narayana Nethralaya,Bangalore,India;University Eye Clinic Maastricht,Maastricht University Medical Center (MUMC+),Maastricht,Netherlands
Purpose
To define the external scleral sulcus (ESS) on a Scheimpflug image and use it for a morphometric analysis of corneal white-to-white (WtW). To study the relationship between corneal WtW and corneal tomography.
Setting
Department of Cornea and Refractive Surgery, Narayana Nethralaya, Bangalore, India.
Methods
One random eye of 353 subjects aged 5-18 years underwent Pentacam HR (OCULUS Optikgeräte GmbH). A novel technique using densitometry on Pentacam was used to measure WtW. Multiple regression models with WtW and other Pentacam parameters were built. The prediction agreement was validated using the intraclass correlation coefficient (ICC). Using ICC, the estimated horizontal WtW (hWtW) was validated against digital calliper measurement. P-value <0.05 was considered significant. Vertical, hWtW, maximum (maxWtW) and minimum (minWtW) WtW and their meridians were defined. Their associations with Pentacam parameters were analyzed to predict keratometry (K), astigmatism and its axis, and Belin/Ambrósio enhanced ectasia display deviation (BAD-D).
Results
The ICC (95% CI) between calliper and hWtW was 0.96 [0.93, 0.97]. Multiple regression prediction of astigmatism, astigmatism axis, Kmean, and BAD-D using WtW parameters, anterior chamber depth, corneal volume, and distance from the corneal thinnest location to apex were significant (p<0.001). These predictions achieved an ICC of 0.34 [0.18, 0.46], 0.82 [0.78, 0.86], 0.87 [0.84, 0.89] and 0.81 [0.76, 0.84], respectively. The astigmatism axis prediction depended on the meridian of minWtW and maxWtW.
Conclusions
The WtW metrics strongly correlated with the astigmatism axis, keratometry and BAD-D. The spatial description of WtW may have an important role in corneal treatment planning and disease diagnoses.