Automated assessment of corneal fluorescein staining based on digital image analysis

Session Details

Session Title: Cornea: Medical

Session Date/Time: Monday 16/09/2019 | 08:30-10:30

Paper Time: 10:12

Venue: Free Paper Forum: Podium 2

First Author: : F.Bernabei ITALY

Co Author(s): :    M. Pellegrini   F. Moscardelli   G. Giannaccare   M.Pellegrini                     

Abstract Details

Purpose:

In this study, we employed a new automated method based on digital image analysis for the quantification and the morphological characterization of corneal fluorescein staining (CFS) in patients with dry eye disease (DED) owing to Sjögren syndrome (SS) and ocular graft versus-host disease (oGVHD). The aim of the study was: i) to compare this analysis with traditional subjective grading techniques in terms of both performance and reliability for the quantification of CFS; ii) to evaluate its efficacy in identifying different CFS patterns; iii) to assess its efficiency in distinguishing SS from oGVHD. 

Setting:

Ophthalmology Unit, S.Orsola-Malpighi University Hospital, University of Bologna, Italy

Methods:

Slit-lamp photographs of corneal staining obtained from 40 DED patients (20 with SS and 20 with oGVHD;) were evaluated. Images were subjectively graded using Oxford and National Eye Institute (NEI) scales, while the staining pattern was classified as micropunctate, macropunctate, coalescent or patch. The corneal staining index (CSI), defined as the ratio between the staining area and the total corneal area, was calculated automatically using the software ImageJ. Particles analysis was used to calculate mean area, circularity and roundness of staining spots. The correlations between the subjective grading and the objective measurements were evaluated with Spearman’s correlation analysis.

Results:

CSI was significantly correlated with Oxford and NEI scales (respectively Rs=0.823 and Rs=0.773; both p<0.001), and showed an excellent interobserver reliability (ICC=0.988 [95% CI: 0.978 to 0.994]). The mean area of staining spots calculated with particles analysis was significantly correlated with the subjective classification of the staining pattern (Rs=0.550, p<0.001). The circularity and roundness of staining spots was significantly higher in oGVHD patients compared to SS (respectively, 0.51±0.11 vs 0.44±0.10, p=0.040; 0.61±0.03 vs 0.59±0.02, p=0.004).

Conclusions:

Traditional grading scales of CFS are subjective and observer dependent, being susceptible to poor reproducibility and high inter and intraobserver variance. The new automated techinque used in this study showed excellent reliability, and demonstrated strong correlations with subjective grading scales. The objective assessment of the staining pattern morphology with particle analysis was able to differentiate oGVHD patients from SS. The automated evaluation of CFS may be useful in multicenter clinical trials on DED, with the advantage of standardizing grading, and providing greater precision when assessing treatment efficacy.

Financial Disclosure:

None