Peer-reviewed Articles

Please use the year list below to look at past peer-reviewed articles.


Blackie,C. A., Coleman,C. A., Nichols,K. K., Jones,L., Chen,P. Q., Melton,R., Kading,D. L., O’Dell,L. E., Srinivasan,S. Asingle vectored thermal pulsation treatment for meibomian gland dysfunction increases mean comfortable contact lens wearing time by approximately 4 hours per day Clinical Ophthalmology 2018;12169-183 [ Show Abstract ]

Purpose: To evaluate the effect of a single vectored thermal pulsation (VTP) treatment in contact lens wearers with meibomian gland dysfunction (MGD) and dry eye symptoms. Methods: The prospective, nonsignificant risk, open-label, randomized, multi-center clinical trial included 55 soft contact lens (SCL) wearers with MGD and evaporative dry eye. Subjects were randomized to the single VTP treatment group or an untreated control. The controls received a crossover VTP treatment at 3 months (crossover treatment group). Primary effectiveness measures were meibomian gland secretion (MGS) score and Standard Patient Evaluation of Eye Dryness (SPEED) that were evaluated at baseline, at 1 and 3 months post-VTP treatment, and at 1 month post-VTP treatment in the crossover treatment group. Exploratory variables included fluorescein tear break-up time (TBUT), lid wiper epitheliopathy (LWE), lid parallel conjunctival folds (LIPCOF), ocular surface staining, frequency of over-the-counter (OTC) drop use, and hours of comfortable contact lens wear. Results: At 3 months, the treatment group showed significantly greater mean change from baseline in MGS (12.4±9.1 vs 1.4±6.4, p˂0.0001), SPEED (−8.4±4.7 vs −0.7±4.4, p˂0.0001) and significantly greater improvement in exploratory variables (TBUT, LWE, and frequency of OTC drop use) relative to the controls. Mean comfortable contact lens wearing time increased by 4.0±3.9 hours at 1 month. This was sustained for 3 months with no change in the control group. The crossover treatment group demonstrated similar results to the treatment group at 1 month post-VTP. Conclusion: In SCL wearers with MGD, a single VTP treatment significantly improved mean meibomian gland function and significantly reduced dry eye signs and symptoms compared to an untreated control. The treatment increased mean comfortable lens wearing time by 4 hours (approximately doubling the pretreatment findings). This was sustained for up to 3 months post-treatment on average. © 2018 Blackie et al.

Delaveris,A., Stahl,U., Madigan,M., Jalbert,I. Comparative performance of lissamine green stains Contact Lens and Anterior Eye 2018;41,1:23-27 [ Show Abstract ]

Purpose To investigate the performance of lissamine green strips from different manufacturers. Additionally, the repeatability, need for sequential dye instillation and impact of repeated lid evertion on lid wiper staining were assessed. Methods Study 1 was a prospective, randomised cross-over study where controlled volumes of lissamine green solution prepared from strips (Biotech, Lissaver, GreenGlo, OPGreen) were instilled (right eye: single; left eye: double instillation) on five different days, with OPGreen being tested twice. Lids were everted and digital photographs taken, which were later assessed by a masked observer. Study 2 was an investigator-masked, randomised, controlled study testing the impact of single versus repeated lid evertion. Lid wiper staining was graded (0 to 3 in 0.5 steps). Results Lid wiper staining differed significantly between lissamine green solutions, with GreenGlo showing the highest amount of staining, and Lissaver the least (all p > 0.009). There were no differences in lid wiper staining over two days, using the OPGreen solution (all p > 0.05). The number of drops instilled (single versus double) did not significantly affect lid wiper staining (all p > 0.05). Repeated lid evertion increased lid wiper staining (p = 0.007 when combined with double drop instillation). Light absorbance patterns and measured concentrations aligned with clinical findings. Conclusion There were significant differences in performance between lissamine green solutions. Lid wiper staining was impacted by repeated lid evertion but sequential instillation and use of the Korb grading scale provided little advantage over simpler methods Clinicians must consider this when investigating lid wipers, especially when interpreting a negative finding. © 2017 British Contact Lens Association

McCanna,D. J., Oh,S., Seo,J., Coles-Brennan,C., Fadli,Z., Subbaraman,L. N., Jones,L. W. The effect of denatured lysozyme on human corneal epithelial cells Investigative Ophthalmology and Visual Science 2018;59,5:2006-2014 [ Show Abstract ]

PURPOSE. During contact lens wear, the amount of lysozyme deposited on contact lenses varies depending on the lens material. The binding of lysozyme to some contact lens materials may result in a conformational change that denatures the protein to an inactive form. This investigation evaluated the effect that denatured lysozyme has on human corneal epithelial cells (HCECs) by measuring cell viability and the release of inflammatory cytokines. METHODS. HCECs were exposed to lysozyme that was denatured to various activity levels. After 24-hour exposure to the lysozyme (1.9 mg/mL) in growth media, the cells were evaluated for cell viability using confocal microscopy. The metabolic activity of the cells was determined using an alamarBlue assay. Cell supernatants were analyzed for inflammatory cytokines. RESULTS. Using confocal microscopy, there was no detectable change in the viability of the HCECs after exposure to the denatured lysozyme. However, using alamarBlue, a decrease in the metabolic activity of the HCECs exposed to denatured lysozyme was detected. HCECs exposed to lysozyme that was 67%, 47%, and 22% active showed a reduction in metabolic activity when compared with native (100% active) lysozyme and the media controls (P < 0.05). Exposure to the denatured lysozyme also caused an increase in the release of inflammatory cytokines (P < 0.05) from the HCECs. CONCLUSIONS. The results of this study show that denatured lysozyme can have a detrimental effect on HCECs. Both a reduction in metabolic activity and an increase in the release of inflammatory cytokines occurred after HCEC exposure to denatured lysozyme. © 2018 The Authors.

Phan,C. -M, Weber,S., Mueller,J., Yee,A., Jones,L. A rapid extraction method to quantify drug uptake in contact lenses Translational Vision Science and Technology 2018;7,2: [ Show Abstract ]

Purpose: To develop a simple extraction procedure to quantify the uptake of four topical ocular pharmaceutical drugs into contact lenses (CLs). Methods: Four silicone hydrogel (SH) CLs (balafilcon A, senofilcon A, lotrafilcon B, comfilcon B) and four conventional hydrogel (CH) CLs (nesofilcon A, hilafilcon B, nelfilcon A, etafilcon A) were evaluated. The drugs studied were natamycin, moxifloxacin, timolol maleate, and ketotifen fumarate. For drug incubation, three CLs of each type were placed in 1 mL of 1 mg/mL drug-loading solution for 24 hours. The lenses were then extracted in 2 mL methanol for 2 hours. This process was repeated to obtain a total of three extraction cycles. Detection of natamycin, moxifloxacin, ketotifen fumarate, and timolol maleate were measured by absorbance at 305, 287, 297, and 295 nm, respectively. Results: The majority of the drugs were extracted after the first extraction cycle (P 0.05). Conclusions: This study provides a simple approach to determine drug uptake into CLs. This method can also be modified, such as changing the extraction time, extraction cycles, or extraction solvent to better suit other drugs and CL combinations. Translational Relevance: There is considerable interest in using CLs for ocular drug delivery. Accurately quantifying drug uptake on CLs has been a challenge. Hence, this study provides a simple method to quantify drug uptake in CLs. © 2018 The Authors.

Stahl,U., Jalbert,I. Exploring the links between contact lens comfort, osmolarity and lid wiper staining Contact Lens and Anterior Eye 2018;41,1:110-116 [ Show Abstract ]

Purpose Contact lens discomfort remains poorly understood, not least due to lack of associations between clinical signs and symptoms. This study aimed to explore the relationships between osmolarity, comfort and lid wiper epitheliopathy in contact lens wear. Methods Twenty subjects participated in a randomized, cross-over study where comfilcon A and lotrafilcon A lenses were each worn for 10 days separated by a 7 days washout period. Tear and contact lens osmolarity, ocular symptoms including comfort, tear stability and production, and lid wiper epitheliopathy were measured. Results Comfort and tear stability decreased and upper lid wiper staining and foreign body sensation increased with lens wear. These were not affected by lens type. A reduction in tear production was seen after 10 days of comfilcon A lens wear. High proportions of lid wiper epitheliopathy were observed at the upper (range 65%–85%) and lower (range 90%–100%) lid margins. Tear and contact lens osmolarity were unaffected by lens wear or type. Contact lens osmolarity was associated with comfort (r = 0.45, p = 0.009). Tear osmolarity moderately correlated with tear stability (r = -0.53, p = 0.014) and tear production (r = -0.44, p = 0.012) but not with lid wiper staining. Conclusions A relationship between comfort and contact lens osmolarity and between tear osmolarity and tear stability and production were found, however, this study was unable to demonstrate an association between comfort and tear osmolarity or lid wiper epitheliopathy. Further studies using contact lenses with a wider range of comfort responses are warranted to investigate these associations further. © 2017 British Contact Lens Association