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Scientific Presentations

2019

Jones L, Jabeen A, Subbaraman L, Heynen M, Keir N, Srinivasan S. Method optimization to quantify four different neuropeptides in the human tear film Global Specialty Lens Symposium, Las Vegas, Nevada, 2019 [ PDF ]

Jones L, Yee A, Jabeen A, Subbaraman L, McCanna D, Phan CM. Novel in-vitro method to study bacterial interaction with contact lenses Global Specialty Lens Symposium, Las Vegas, Nevada, 2019 [ PDF ]

2018

Jabeen A, Subbaraman L, Heynen M, Srinivasan S, Jones L. Method Optimization to Quantify Four Neuropeptides in the Human Tear Film American Academy of Optometry, San Antonio, USA, 2018 [ Show Abstract ][ PDF ]

Purpose: Ocular surface neuropeptides play a key role in modulating the infiltration and activation of immune cells in both tearing and ocular discomfort. The purpose of this study was to optimize a method to quantify the amount of four neuropeptides - calcitonin gene-related peptide (CGRP), Substance P (SP), Neuropeptide Y (NPY) and Vasoactive Intestinal Peptide (VIP) - in the human tear film

Methods: Basal and flush tears (following instillation of 20 microliters of saline on the ocular surface) of 8 healthy participants were collected from the right and left eyes respectively, using a microcapillary method on day 1. On day 2, the same procedure was repeated. The concentration of the four neuropeptides in the tears was determined using an enzyme-linked immunosorbent assay (ELISA) method. The ELISA kits were tested for specificity and sensitivity as per manufacturer’s guidelines and the experiments were repeated three times to determine reproducibility. The limit of detection was based on the variance of the blank samples and the variance of the lowest level of each individual tear samples added.

Results: RM-ANOVA showed no statistical difference in the concentration of CGRP, NPY and VIP between basal and flush tears for days 1 and 2 (p > 0.05). However, statistically significant differences were found for SP between basal and flush tears for day 1 (p = 0.037) and flush tears for days 1 and 2 (p = 0.018) respectively.

Conclusion: ELISA is a sensitive method that can be adopted to quantify neuropeptides in the human tear film. The optimized technique can be used to identify differences in the level of various neuropeptides in patients with contact lens discomfort and varying degrees of dry eye.

Yee A, Jabeen A, Subbaraman L, McCanna D, Phan C-M, Jones L. Novel In-Vitro Method to Study Bacterial Interaction with Contact Lenses American Academy of Optometry, San Antonio, USA, 2018 [ Show Abstract ][ PDF ]

Purpose: Previous in-vitro studies have used a “soak” or closed vial method to assess bacterial binding to contact lenses (CL). The purpose of this study was to develop a novel in-vitro drip model to determine if bacterial adhesion to a CL material was possible. The novel in-vitro drip model would more closely resemble an accurate eye model in comparison to current methods undertaken.

Methods: The novel in-vitro drip method consists of a 5.5 mL syringe with saline solution and a flow rate controller dispensing 5 µl of saline solution containing the bacteria. The consistent drip volume is adjustable and mimics the normal human tear volume and flow. The solution flows through a silicone tube and onto a CL. The CL was placed on a sterile glass eyeball in an enclosed container to maintain the environment’s humidity. In the soak method, the CL was placed on top of a sterile glass eyeball and placed in the enclosed container with a 5 mL saline solution of 1.0 x 107 colony forming units (CFU)/mL. For both methods, lenses were incubated in the solution for 16 hours. After removal, the viable cells were diluted in serial dilutions. Aliquots of each dilution were plated on a trypticase soy agar plate and incubated for 24 hours at 37°C. After 24 hours, the CFU per lens were calculated manually under magnification.

Results: Using the in-vitro drip method, adhesion of Staphyloccocus aureus onto senofilcon A was successfully demonstrated. Preliminary analysis showed no significant difference (p = 0.34) between the drip and soak method when compared at high CFU/mL.

Conclusion: The novel drip method is a promising alternative to the conventional soak method, as this model is closer to the contamination that would occur in a human eye. The drip method may be an acceptable method of testing once the method can be further developed and tested in future studies, using a variety of lenses and bacteria.

2017

Jabeen A, Subbaraman L, Babaei Omali N, Srinivasan S, Jones L. Method optimization to quantify calcitonin gene-related peptide (CGRP) in human tear film Optom Vis Sci 2017;94: E-Abstract 175270