Ocular Surface Immune Cell Profiles in Contact Lens-Induced Discomfort.

Purpose: Contact lens-induced discomfort (CLD) remains a primary factor in discontinuation or prevention of contact lens wear. Thus, we investigated the role of ocular surface immune cells in subjects with CLD. Methods: Habitual contact lens (CL) wearers with CLD (n = 19; 38 eyes) and without CLD (n = 21; 42 eyes) as determined by the Contact Lens Dry Eye Questionnaire-8 was included in a trial. Enrolled subjects used either of the two types of CL (designated as CL-A or CL-D). Ocular surface cells from the bulbar conjunctiva were obtained by impression cytology. The collected cells were phenotyped using fluorochrome-conjugated antibodies specific for leukocytes (CD45+), neutrophils (CD66b+,High,Low), macrophages (CD163+), T cells (CD3+CD4+, CD3+CD8+), natural killer (NK) cells (CD56+, High, Low), natural killer T (NKT) cells (CD3+CD56+), and gamma delta T (γδT) cells (CD3+γδTCR+) by flow cytometry. Further, corneal dendritic cell density (cDCD) was also determined using in vivo confocal microscopy. Results: Significantly higher proportions of CD45+ cells were observed in subjects with CLD compared to those without CLD. The percentages of CD66bTotal,Low, CD163+, pan T cells, CD4+T cells, CD8+T cells, CD56Total,High,Low (NK) cells, and NKT cells, as well as the CD4/CD8 ratio, were significantly higher in CLD subjects. The proportion of T cells (CD4, CD8, CD4/CD8 ratio, NKT cells) and macrophages exhibited a direct association with discomfort score. The percentages of CD45+, CD66bTotal,Low, CD163+, CD3+, CD56Total,High,Low, and NKT cells and cDCD were significantly higher in CLD subjects wearing CL-D. The percentages of CD66bHigh, CD4+T cells, CD8+T cells, NKT cells, and CD4/CD8 ratio were significantly higher in CLD subjects wearing CL-A. Conclusions: Increased proportions of ocular surface immune cells are observed in CLD, and the lens type could impact the immune cells associated with CLD. Translational Relevance: The association between the proportion of altered ocular surface immune cell subsets and contact lens-induced discomfort underpins the importance of considering immune-related aspects during contact lens development and in the clinical management of ocular surface pain.

Acoustic analysis of crabeater seal (Lobodon carcinophaga) vocalizations in the Southern Kerguelen Plateau region of East Antarctica.

Crabeater seals are circumpolar, ice-dependent seals that produce distinct vocalizations during the breeding season. This study provides the first description of the acoustic repertoire of the crabeater seal in East Antarctica, using data from a stationary hydrophone at 1.8 km depth in the Southern Kerguelen Plateau region in 2014-2015. Two call types were identified in the data set: the low and the high moan calls. Of the 8821 calls detected, 92.5% were classified as low moan calls and 7.5% were high moan calls. The mean duration of the two call types was similar (2.3 and 2.8 s, respectively), however, the high moan calls had a higher frequency range (1020-4525 Hz, n = 11) than the low moan calls (360-2753 Hz, n = 120). The calls were primarily detected in the austral spring. Diel analysis showed that the low moan calls were mostly made at nighttime or proximal to dusk and dawn. The results of this study could aid in the development of automated detectors for crabeater seal vocalizations. This would facilitate comparisons of the distribution and abundance of the species using extant acoustic data and could increase knowledge on the breeding behavior of crabeater seals.

In vivo imaging of riboflavin penetration during collagen cross-linking with hand-held spectral domain optical coherence tomography.

PURPOSE: To compare the effect of complete versus grid-like epithelial removal on riboflavin penetration during collagen cross-linking (CXL) in vivo using hand-held spectral domain optical coherence tomography (OCT, Bioptigen Inc). METHODS: In this prospective, observational, comparative case series, patients with progressive keratoconus undergoing CXL with riboflavin and ultraviolet A (UVA) light were enrolled. Twenty eyes (20 patients) undergoing CXL using 0.1% riboflavin and UVA light (365 nm) were imaged intraoperatively at 30 and 60 minutes after starting the procedure, using hand-held spectral domain OCT. In 10 eyes, the epithelium was removed completely in the central 7-mm zone (complete removal group) whereas in the remaining 10 eyes, the epithelium was removed in a grid pattern, leaving behind intact islands of epithelium (grid-like removal group). The depth of hyperreflective band (representing penetration of riboflavin) in the anterior corneal stroma was measured. RESULTS: In the complete removal group, the hyper-reflective band was homogenous, extending to a mean depth of 54.2±5.2 µm and 72.4±7.1 µm at 30 and 60 minutes, respectively (P<.001). In the grid-like removal group, the mean depth of the hyperreflective band was uneven, being significantly more in the "epithelium off" areas (56.90±4.66 µm and 74.2±6.7 µm at 30 and 60 minutes, respectively) (P<.001) compared to the "epithelium on" areas (18.9±2.3 µm and 24.7±2.3 µm at 30 and 60 minutes, respectively) (P<.001). CONCLUSIONS: Epithelial removal appears to be an essential step prior to performing CXL, as an intact epithelium appears to block penetration of riboflavin in the anterior corneal stroma.