Purpose Creating wide-field montages of the human corneal subbasal nerve plexus using laser scanning in vivo confocal microscopy (IVCM) requires considerable expertise and remains highly labor intensive. A typical montage contains several hundred images to be quality checked and manually arranged. The purpose of this study was to develop and validate software for off-line montaging of IVCM images of the living human cornea. Methods The software was developed and tested using four large data sets of IVCM images from normal human corneas. Two of the data sets were used for calibration purposes, the remaining images served as a validation set. Techniques utilized included image binarization, clustering, key-point generation, and feature-based stitching. A range of tests involving computer processing and visual inspection were applied to audit and compare the automated montages with manually constructed montages. Results The original IVCM images (N = 2565) from four corneas were processed into image groups, reducing the number of effective images by 68% to 86%. Each data set contained a large primary grouping. A clustering strategy was used to reduce the total potential workload by 57%. Both programmatic and visual inspection confirmed the method was robust to errors, with a specificity of 100% (i.e., no falsely matched images). The time taken to complete the montage varied from 1.5 to 3 hours. Conclusions Computer-driven image stitching is a useful, effective, and time-saving tool for studies involving IVCM corneal nerve imaging. Further research will extend and optimize these methods.

Fatigue-induced reductions in saccade velocity have been reported following acute, prolonged exercise. Interestingly, the detrimental impact of fatigue on oculomotor control can be prevented by a moderate dose of caffeine. This effect may be related to central catecholamine upregulation via caffeine’s action as an adenosine antagonist. To test this hypothesis, we compared the protective effect of caffeine on oculomotor control post-exercise to that of a norepinephrine-dopamine reuptake inhibitor. Within a placebo-controlled crossover design, 12 cyclists consumed placebo, caffeine or a norepinephrine-dopamine reuptake inhibitor (bupropion) during 180 minutes of stationary cycling. Saccades, smooth pursuit and optokinetic nystagmus were measured using infrared oculography. Exercise fatigue was associated with an 8 ± 11% reduction in the peak velocity of prosaccades, and a 10 ± 11% decrement in antisaccade peak velocity. Optokinetic nystagmus quick phases decreased in velocity by 15 ± 17%. These differences were statistically significant (p < 0.05). Norepinephrine-dopamine reuptake inhibition and caffeine prevented fatigue-related decrements in eye movement velocity. Pursuit eye movements and visual attention were unaffected. These findings show that norepinephrine-dopamine reuptake inhibition protects oculomotor function during exercise fatigue. Caffeine’s fatigue-reversing effects on eye movements appear to be mediated, at least in part, via modulation of central catecholamines.

The detection of vision problems in early childhood can prevent neurodevelopmental disorders such as amblyopia. However, accurate clinical assessment of visual function in young children is challenging. optokinetic nystagmus (OKN) is a reflexive sawtooth motion of the eye that occurs in response to drifting stimuli, that may allow for objective measurement of visual function in young children if appropriate child-friendly eye tracking techniques are available. In this paper, we present offline tools to detect the presence and direction of the optokinetic reflex in children using consumer grade video equipment. Our methods are tested on video footage of children (N = 5 children and 20 trials) taken as they freely observed visual stimuli that induced horizontal OKN. Using results from an experienced observer as a baseline, we found the sensitivity and specificity of our OKN detection method to be 89.13% and 98.54%, respectively, across all trials. Our OKN detection results also compared well (85%) with results obtained from a clinically trained assessor. In conclusion, our results suggest that OKN presence and direction can be measured objectively in children using consumer grade equipment, and readily implementable algorithms.