Clinical Ophthalmology (Mar 2023)
Validation of a Modified National Eye Institute Grading Scale for Corneal Fluorescein Staining
Abstract
Kenneth Sall,1 Gary N Foulks,2 Andrew D Pucker,1 Karen L Ice,1 Richard C Zink,1 George Magrath1 1Lexitas Pharma Services, Inc, Durham, NC, USA; 2University of Louisville (Retired), Louisville, KY, USACorrespondence: Kenneth Sall, Lexitas Pharma Services, Inc, 313 Foster St, Durham, NC, 27701, USA, Tel +1 919 205-0012, Email [email protected]: Validation of the novel Lexitas modified NEI scale for use in assessment of corneal fluorescein staining.Patients and Methods: A series of 18 illustrations and 14 clinical photographs depicting varying severity levels of corneal fluorescein staining were assessed by 3 independent examiners. Regions of the cornea were graded for staining severity based on 3 different grading scales: the original NEI staining scale (density-based scoring; 0– 3 scale), a structured version of the NEI scale (dot-count scoring; 0– 3 scale), and the Lexitas modified NEI staining scale (0– 4 scale with half-point increments). Kappa statistics (simple and weighted) were computed to determine intra-examiner image grading repeatability for each examiner over 2 separate assessments. Inter-examiner assessment reliability utilized the scores from the first read of each examiner, and pairs of examiners to compute kappa statistics.Results: Data was analyzed from the scores provided by the examiners from each gradable corneal region on 32 images (18 illustrations and 14 photographs) for a total of 154 corneal regions across the 3 grading scales for each validation run. The mean intra-examiner simple/weighted kappa values using the NEI density, NEI dot count, and the Lexitas modified NEI staining scales were 0.67/0.72, 0.91/0.94, 0.80/0.92 for the graded illustrations, and 0.83/0.88, 0.76/0.85, 0.77/0.88 for the graded photographs, respectively. The mean inter-examiner simple/weighted kappa values using the NEI density, NEI dot count, and the Lexitas modified NEI staining scales were 0.59/0.65, 0.86/0.90, and 0.78/0.91 for the graded illustrations, and 0.80/0.88, 0.84/0.89, 0.69/0.88 for the graded photographs, respectively.Conclusion: The expanded scale of the Lexitas modified NEI staining scale demonstrated a high degree of reliability and repeatability of grading assessments within and across individual examiners, comparing favorably with the original NEI staining scale. A future investigation into the in-office utility of the Lexitas modified NEI staining scale is warranted.Keywords: clinical trials, corneal sodium fluorescein staining, dry eye disease, repeatability, validation
