Comparison of an objective method of measuring bulbar redness to the use of traditional grading scales.

PURPOSE: The primary objective was to compare measures of bulbar redness objectively using a photometric method with standard grading methods. Measures of redness were made on 24 participants wearing a silicone hydrogel contact lens in one eye for overnight wear. This report compares hyperaemia after 1 week of daily wear (baseline) with redness measured after 6 months of overnight wear. METHOD: A new method of objectively measuring bulbar conjunctival redness was performed using the Spectrascan650 Photometer by Photo Research under fixed illumination. Photometric measures in CIEu(*) chromaticity values involve the measurement of chromaticity, a physical analogue of redness, greenness and blueness in the image. This method was validated in Part 1 of the study using repeated measurements on the photographic CCLRU scale. In Part 2 of the study, the photographic grading scale (CCLRU) from 0 (none) to 100 (extreme) was used to make the comparison. RESULTS: Part 1 indicated that the photometer provides a repeatable and reliable measure of bulbar redness (CCC=0.989). A moderately strong and significant correlation was found between the CIEu(*) chromaticity values and the analogue data (R=0.795, p=0.000) at each measurement session (from baseline to 1 day, 1 week, and 1, 3 and 6 months of overnight wear). CONCLUSIONS: This new standardized and objective method of measuring bulbar redness has great potential to replace subjective grading scales, especially with multi-centre studies, where variability between investigators occurs. This method may also detect smaller changes between visits or between eyes.     

Fitting an MSD (Mini Scleral Design) rigid contact lens in advanced keratoconus with INTACS

Keratoconus is a bilateral degenerative disease characterized by a non-inflammatory, progressive central corneal ectasia (typically asymmetric) and decreased vision. In its early stages it may be managed with spectacles and soft contact lenses but more commonly it is managed with rigid contact lenses. In advanced stages, when contact lenses can no longer be fit, have become intolerable, or corneal damage is severe, a penetrating keratoplasty is commonly performed. Alternative surgical techniques, such as the use of intra-stromal corneal ring segments (INTACS) have been developed to try and improve the fit of rigid contact lenses in keratoconic patients and avoid penetrating keratoplasties. This case report follows through the fitting of rigid contact lenses in an advanced keratoconic cornea after an INTACS procedure and discusses clinical findings, treatment options, and the use of mini-scleral and scleral lens designs as they relate to the challenges encountered in managing such a patient. Mini-scleral and scleral lenses are relatively easy to fit, and can be of benefit to many patients, including advanced keratoconic patients, post-INTAC patients and post-penetrating keratoplasty patients.     

A Shifted Composition of the Lung Microbiota Conditions the Antifungal Response of Immunodeficient Mice

The microbiome, i.e., the communities of microbes that inhabit the surfaces exposed to the external environment, participates in the regulation of host physiology, including the immune response against pathogens. At the same time, the immune response shapes the microbiome to regulate its composition and function. How the crosstalk between the immune system and the microbiome regulates the response to fungal infection has remained relatively unexplored. We have previously shown that strict anaerobes protect from infection with the opportunistic fungus Aspergillus fumigatus by counteracting the expansion of pathogenic Proteobacteria. By resorting to immunodeficient mouse strains, we found that the lung microbiota could compensate for the lack of B and T lymphocytes in Rag1^–/– mice by skewing the composition towards an increased abundance of protective anaerobes such as Clostridia and Bacteroidota. Conversely, NSG mice, with major defects in both the innate and adaptive immune response, showed an increased susceptibility to infection associated with a low abundance of strict anaerobes and the expansion of Proteobacteria. Further exploration in a murine model of chronic granulomatous disease, a primary form of immunodeficiency characterized by defective phagocyte NADPH oxidase, confirms the association of lung unbalance between anaerobes and Proteobacteria and the susceptibility to aspergillosis. Consistent changes in the lung levels of short-chain fatty acids between the different strains support the conclusion that the immune system and the microbiota are functionally intertwined during Aspergillus infection and determine the outcome of the infection.     

Tear turnover rate is reduced in patients with symptomatic dry eye.

PURPOSE: Tear turnover rate (TTR) is defined as the percent decrease of fluorescein concentration in the tears per minute after the instillation of fluorescein. The purpose of this study was to examine differences in TTR in a sample with symptoms of dry eye and an asymptomatic control sample using the Fluorotron Master Fluorophotometer. METHODS: TTR was measured using the OcuMetrics Fluorotron Master. It measures the decay of the fluorescence of high molecular weight fluorescein FITC Dextran instilled into the tear film. Twenty participants (post-menopausal women) were enrolled in the study (10 asymptomatic (age 64.7 +/- 6.99) and 10 symptomatic (age 61.5 +/- 7.98)). Participants were grouped according to either a positive (symptomatic) or negative (asymptomatic) McMonnies Dry Eye Questionnaire, i.e., an indication of self-reported ocular dryness and the use of rewetting/lubricating drops (questions 4 and 5). TTR was measured in the afternoon only. Measurements were made on the right eye with a controlled blink rate (15 blinks/min), for up to 30 min, post-insertion of 2 microl of 2% FITC Dextran (MW 9500). The scan data were used to construct a graph of log fluorescein concentration (ng/ml) as a function of time and the TTR calculated (%/ min = (1- ln (slope)) x 100). RESULTS: There was a significant difference in the TTR between symptomatic and asymptomatic subjects. Mean TTR (symptomatic) was 4.89 +/-2.74%/min (range, 2.04-11.81) and mean TTR (asymptomatic) was 11.85 +/- 3.31%/min (range, 5.76-16.45) (P < 0.0001). CONCLUSIONS: Fluorophotometry may be used to demonstrate differences in the tear turnover rate in this post-menopausal group of women, with patients experiencing symptoms of dry eye having a lower TTR than the normals.