Centration of donor trephination in human corneal transplantation

Automated digital analysis of intraoperative keratoscopy and its correlation with postoperative astigmatism after big-bubble deep anterior lamellar keratoplasty

PURPOSE

To investigate the correlation between postoperative corneal astigmatism (PCA) and values of intraoperative keratoscopy analyzed with a newly developed automated technique in patients undergoing big-bubble (BB) deep anterior lamellar keratoplasty (DALK).

METHODS

Photographs of keratoscope rings taken at the end of BB-DALK were analyzed using ImageJ for the calculation of "roundness" (R): values = 1 indicate a perfect circle. Pearson's correlation was used to evaluate the relationship between R and PCA that measured 1 week (V1), 3 months (V2), and 18 months (V3), postoperatively. The area under the curve (AUC) of receiver operating characteristic (ROC) curve was used to evaluate the accuracy of R for identifying patients with PCA < 3 diopters (D). The point on the ROC curve nearest to the coordinate (0,100) was used as a cutoff to determine sensitivity and specificity.

RESULTS

Data from 121 patients were included. The mean value of R*was 0.93 ± 0.04 (range 0.76-0.99). R showed a significant correlation with PA at V3 (R = - 0.42, P < 0.01). The ROC curve had an AUC of 0.69 (95% CI 0.59-0.79). A cutoff value of R = 0.93 had a sensitivity of 70.3% and specificity of 61.0% for identifying patients with PA < 3D at V3.

CONCLUSIONS

This new digital analysis of keratoscope rings allows to identify with reasonably good diagnostic accuracy patients with low values of post-DALK astigmatism correctable with spectacles.

Astigmatism Orientation After Deep Anterior Lamellar Keratoplasty for Keratoconus and Its Correlation With Preoperative Peripheral Corneal Astigmatism

PURPOSE

To evaluate the orientation of keratometric astigmatism (KA) after deep anterior lamellar keratoplasty (DALK) for keratoconus and its correlation with preoperative peripheral KA.

METHODS

This is a retrospective, single-center observational study including keratoconic patients undergoing DALK between January 2016 and January 2017 with regular astigmatism postoperatively. The orientation of postoperative KA was classified as with-the-rule (WTR), against-the-rule, or oblique and was correlated with the corresponding preoperative peripheral KA, calculated by the sinusoidal fitting of points of the axial keratometric power map at 8 mm diameter.

RESULTS

Forty-one keratoconic eyes were included, with the most common orientation of KA post-DALK being WTR (65.9%), followed by against-the-rule (19.5%) and oblique (14.6%). A significant correlation was found between preoperative peripheral KA and post-DALK KA regarding axis (P < 0.001, r = 0.88) and power (P = 0.0128, r = 0.23).

CONCLUSIONS

The axis of post-DALK astigmatism and to a lesser extent its respective power in keratoconic eyes can be predicted using the preoperative peripheral KA, with "WTR" being the most common astigmatic orientation.