Co-existence of Neurotrophic Keratopathy in Eyes with Limbal Stem Cell Deficiency.

PURPOSE: To investigate whether neurotrophic keratopathy is present in limbal stem cell deficiency (LSCD) by measuring corneal sensation and characterizing corneal subbasal nerve plexus. DESIGN: Prospective, cross-sectional "case-control" comparative study. METHODS: Forty-six eyes with LSCD and 14 normal eyes were recruited from 2019 to 2022. Corneal sensation was measured using a Cochet-Bonnet esthesiometer and subbasal nerve plexus was imaged using in vivo confocal microscopy (IVCM) at the central cornea and 4 limbal regions. Subbasal nerve density (SND, number of nerve/mm2), subbasal nerve length (SNL, total length of nerve/mm2) and subbasal nerve branch density (SNBD, number of branch/mm2) were quantified. LSCD was graded to stage 1, 2 and 3 using a previously established staging method` consisting of clinical scores, basal cell density, central corneal epithelial thickness and SNL. RESULTS: The mean (±SD) cornea sensation in the central cornea and limbus were 29.2 ± 21.5 and 33.6 ± 15.1 mm in the LSCD group and 57.6 ± 5.8 and 54.3 ± 4.7 mm in the control group, respectively (all P < 0.001). In sectoral LSCD, the sensation in the affected regions (29.1 ± 17.6 mm) decreased significantly compared to the unaffected regions (41.4 ± 18.2 mm, P < 0.001). Central corneal SND, SNL and SNBD were reduced by 84.6%, 82.6%, and 89.2%, respectively in LSCD compared to the control (all P < 0.05). The central corneal sensation negatively correlated with the severity of LSCD (rho = -0.64, P < 0.0001) and positively correlated with SND, SNL, and SNBD (rho=0.63, 0.66, and 0.56, respectively; all P < 0.001). CONCLUSIONS: Corneal sensation was reduced in eyes with LSCD. The degree of corneal sensation reduction positively correlated with the severity of LSCD. This finding demonstrated the co-existence of neurotropic keratopathy in LSCD.

Infectious Keratitis Isolates and Susceptibility in Southern California.

PURPOSE: The purpose of this study was to determine longitudinal trends in prevalence and resistance profiles for infectious keratitis at referral centers in Southern California. METHODS: Cultured infectious keratitis cases from January 1, 2006, through December 31, 2009, and January 1, 2016, through December 31, 2019, at the University of California, Los Angeles, were evaluated. Outcome measures included microbial isolate prevalence and antibiotic/antifungal susceptibility and resistance patterns. RESULTS: One hundred thirty-nine and 315 culture-positive isolates were obtained between 2006-2009 and 2016-2019, respectively. Gram-positive organisms accounted for 65% (2006-2009) and 74% (2016-2019) of bacterial isolates ( P = 0.076). Staphylococcus infections, the most common gram-positive and bacterial isolate in both study epochs, demonstrated increased prevalence from 2006-2009 to 2016-2019 (41% vs. 53%, P = 0.019). Although coagulase-negative Staphylococcus (CoNS) increased from 40% to 58% ( P = 0.0012), the prevalence of methicillin-resistant Staphylococcus aureus was unchanged (28% vs. 28%, P = 0.99). Pseudomonas aeruginosa , the most common gram-negative organism, demonstrated decreased prevalence from 18% to 10% ( P = 0.027). Candida species comprised 3.5% of culture-positive isolates in both epochs. All gram-positive isolates were susceptible to vancomycin, and all Staphylococcus isolates were susceptible to linezolid. Pseudomonas aeruginosa remained susceptible to tested fluoroquinolones (>93%) and aminoglycosides (100%) over time. CONCLUSIONS: In southern California between 2006 and 2019, there was a shift toward Staphylococcus species, with increased CoNS, decreased methicillin-sensitive Staphylococcus aureus , and decreased prevalence of P. aeruginosa . Empiric therapy of vancomycin and a fluoroquinolone or aminoglycoside provides effective antibacterial coverage for predominant bacterial species when culture sensitivities are pending.