Automatic screening of tear meniscus from lacrimal duct obstructions using anterior segment optical coherence tomography images by deep learning.

PURPOSE: We assessed the ability of deep learning (DL) models to distinguish between tear meniscus of lacrimal duct obstruction (LDO) patients and normal subjects using anterior segment optical coherence tomography (ASOCT) images. METHODS: The study included 117 ASOCT images (19 men and 98 women; mean age, 66.6 ± 13.6 years) from 101 LDO patients and 113 ASOCT images (29 men and 84 women; mean age, 38.3 ± 19.9 years) from 71 normal subjects. We trained to construct 9 single and 502 ensemble DL models with 9 different network structures, and calculated the area under the curve (AUC), sensitivity, and specificity to compare the distinguishing abilities of these single and ensemble DL models. RESULTS: For the highest single DL model (DenseNet169), the AUC, sensitivity, and specificity for distinguishing LDO were 0.778, 64.6%, and 72.1%, respectively. For the highest ensemble DL model (VGG16, ResNet50, DenseNet121, DenseNet169, InceptionResNetV2, InceptionV3, and Xception), the AUC, sensitivity, and specificity for distinguishing LDO were 0.824, 84.8%, and 58.8%, respectively. The heat maps indicated that these DL models placed their focus on the tear meniscus region of the ASOCT images. CONCLUSION: The combination of DL and ASOCT images could distinguish between tear meniscus of LDO patients and normal subjects with a high level of accuracy. These results suggest that DL might be useful for automatic screening of patients for LDO.

Prediction of age and brachial-ankle pulse-wave velocity using ultra-wide-field pseudo-color images by deep learning.

This study examined whether age and brachial-ankle pulse-wave velocity (baPWV) can be predicted with ultra-wide-field pseudo-color (UWPC) images using deep learning (DL). We examined 170 UWPC images of both eyes of 85 participants (40 men and 45 women, mean age: 57.5 ± 20.9 years). Three types of images were included (total, central, and peripheral) and analyzed by k-fold cross-validation (k = 5) using Visual Geometry Group-16. After bias was eliminated using the generalized linear mixed model, the standard regression coefficients (SRCs) between actual age and baPWV and predicted age and baPWV from the UWPC images by the neural network were calculated, and the prediction accuracies of the DL model for age and baPWV were examined. The SRC between actual age and predicted age by the neural network was 0.833 for all images, 0.818 for central images, and 0.649 for peripheral images (all P < 0.001) and between the actual baPWV and the predicted baPWV was 0.390 for total images, 0.419 for central images, and 0.312 for peripheral images (all P < 0.001). These results show the potential prediction capability of DL for age and vascular aging and could be useful for disease prevention and early treatment.

Far infrared stimulated emission from the ns and nf Rydberg states of NO.

We report directional far-infrared emission from the υ = 0 vibrational levels of the 9sσ, 10sσ, 11sσ, 9f, and 10f Rydberg states of NO in the gas phase. The emission around 28 and 19 µm from the 9f state was identified as the downward 9f → 8g and subsequent 8g → 7f cascade transitions, respectively. The emission around 38 and 40 µm from the 10f state was identified as the 10f → 9g and 10f → 9dσπ transition, respectively. Following the excitation of the 9sσ, 10sσ, and 11sσ states, the emission around 40, 60, and 83 µm was assigned as the 9sσ → 8pσ, 10sσ → 9pσ, and 11sσ → 10pσ transitions, respectively. In addition to these emission systems originated from the laser-prepared levels, we found the emission bands from the 8f, 9f, and 10f states which are located energetically above the 9sσ, 10sσ, and 11sσ states, respectively. This observation suggests that the upward 8f ← 9sσ, 9f ← 10sσ, and 10f ← 11sσ optical excitation occurs. Since the energy differences between nf and (n + 1)sσ states correspond to the wavelength longer than 100 µm, the absorption of blackbody radiation is supposed to be essential for these upward transitions.

Laser induced amplified spontaneous emission from the f 0(g)(+) (3P0) ion-pair state of I2.

Laser induced amplified spontaneous emission (ASE) from the f 0g (+) ((3)P0) (vf = 1-7) ion-pair state of I2 was directly observed using an optical-optical double resonance technique with the B 0u (+) (vB = 21) valence state as the intermediate state. The emission detected at ~1660 nm was assigned to transitions from the f 0g (+) state to the D 0u (+) ((3)P2) ion-pair state. The transitions observed in the dispersed IR emission spectra were found to be between vibrational levels having the same vibrational quantum numbers in both electronic states, vf = vD. This is due to the almost parallel nature of the potential energy functions of the f 0g (+) and D 0u (+) states, leading to almost unit values for the Franck-Condon factors for vf = vD. That the observed infrared emission is due to ASE is shown by the facts that it propagated in a limited range of solid angles, exhibited a clear threshold against the input-laser power, and had different polarization to that of laser induced fluorescence.