Technical Report: Automatic Measurement of Corneal Nerve Fiber Area Using Versatile Software

Abstract

In vivo confocal microscopy has become a popular method to observe the details of corneal structures. We consider the area of corneal structures to be a versatile index and have measured the areas of various corneal structures using a commercially available software.PURPOSE: This study aimed to evaluate the accuracy of software used to measure the corneal nerve fiber area. METHODS:The corneal structures of 11 healthy volunteers were visualized using in vivo confocal microscopy. The image that most clearly depicted the corneal nerve fibers of each participant was selected for analysis. The corneal nerve fiber area was automatically measured by the software. An experienced ophthalmologist then manually measured the corneal nerve fiber area in each image assessed by the software. The Pearson correlation test was used to determine the correlation coefficient between the corneal nerve fiber areas measured automatically and those measured manually. The correlation between the corneal nerve fiber area and the participant's age was also evaluated. RESULTS:A strong correlation was found between the corneal nerve fiber area measured automatically and the corneal nerve fiber area measured manually (r = 0.98, P = 2.4 Â 10 −7 ). The corneal nerve fiber area was not correlated with participant age, regardless of whether the area was measured automatically (r = −0.26, P = .44) or manually (r = −0.13, P = .71). CONCLUSIONS:The software used in this study automatically measures the corneal nerve fiber area with accuracy similar to that of manual measurement by an experienced ophthalmologist. This software has potential for use in quantifying the areas of various corneal structures.