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Purpose: To compare the single application and two week treatment effects of device-applied (Eyepeace) and manually-applied eyelid massage techniques, as an adjunct to warm compress therapy, on ocular surface and tear film parameters., Methods: Twenty participants (11 females, 9 males; mean age, 27 ± 11 years) with dry eye symptoms were recruited in a two week, investigator-masked, randomised, contralateral-eye trial. Following 10 min of warm compress therapy application (MGDRx EyeBag ® ) on both eyes, eyelid massage therapy was applied to one eye (randomised) by device, and to the fellow eye by manual eyelid massage, once daily for 14 days. Ocular surface and tear film measurements were conducted at baseline, and 15 min post-application by a clinician, then again after 14 days of self-administered daily treatment at home., Results: Baseline clinical measurements did not differ between the treatment groups (all p > 0.05). Following two weeks of treatment, tear film lipid layer grade improved significantly with device massage (p = 0.008), and was marginally greater than manual massage by less than 1 grade (p = 0.03). Although immediate post-treatment improvements in tear film stability were observed in both groups (both p < 0.05), no significant long-term cumulative effects or inter-treatment differences in stability measures were detected (all p > 0.05). Visual acuity, tear meniscus height, conjunctival hyperaemia, ocular surface staining, and meibomian gland dropout did not change during the treatment period (all p > 0.05)., Conclusions: Two weeks of treatment with the eyelid massage device, as an adjunct to warm compress therapy, effected marginally greater improvements in tear film lipid layer thickness than the conventional manual technique, which were statistically but not clinically significant. Future parallel group trials with longer treatment periods and a greater range of disease severity are required., (Copyright © 2019 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.)

Purpose: To evaluate post-lens tear dynamics at two different time points during scleral lens wear in two cohorts with 10 neophytes each., Methods: All subjects wore bilaterally scleral lenses for 5 h on 3 separate visits. Post-lens tear exchange was measured using Out-in method, which required 5 μL of 2% FITC-Dextran instilled on the bulbar conjunctiva during lens wear. Time taken to observe the first sign of fluorescence in post-lens tear reservoir was recorded with a stopwatch. Out-in measurements were collected at 5-hour  post-lens insertion in Group 1 and compared with those obtained at 20 min of lens wear in Group 2. Tear dynamics under the lens was observed in Group 2 with fluorogram using a modified slit-lamp technique (Tan et al., 2018) to monitor post-lens fluorescence intensity and with high-resolution spectral domain optical coherence tomography (ENVISU 2300; Bioptigen Inc.) to measure post-lens tear thickness (PoLTT) over 5 h of lens wear., Results: 60% of subjects in Group 1 achieved Out-in times less than 5 min at 5-hour post-lens insertion, compared with 67% of subjects at 20-min lens wear (Tan et al., 2018). Using qualitative analysis on 60 series of data in Group 2 to compare the changes in fluorescence intensity and PoLTT with respect to lens-wearing time, 27% was due to lens settling, 13% was due to tear exchange and mixing while 60% indicated tear dynamics under scleral lenses was due to a combination of tear exchange, mixing, and lens settling., Conclusion: Tear flow into tear reservoir under a scleral lens on subjects with healthy cornea occurred at 20 min and 5 h after lens insertion. After 5 h of lens wear, roughly one third of the subjects had no tear flow into post-lens reservoir, as the observed decline in post-lens tear fluorescence was predominately due to lens settling., (Copyright © 2018 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.)

Purpose: To describe a new methodology for tear-film dynamics assessment by observing fluorescein decay rate over time and to understand the relationship between the newly defined tear fluorescein washout rate (TFWR) and other measures of the tear film behaviour., Methods: Forty subjects (24F/16M) aged (mean±standard deviation) 31.8±14.2years volunteered for the study. It consisted of the review of medical history, McMonnies questionnaire (McMQ), slit lamp examination, and TFWR using a newly-developed fluorescein profilometry. The repeatability of TFWR measurements was assessed. TFWR estimates were contrasted against patient age, McMQ score, daytime, fluorescein tear film break-up time (FTBUT), tear meniscus height (TMH) and blink frequency., Results: Mean repeatability of the method was 28.13±9.59%. The group mean TFWR was 39±23% at 30-s mark after the beginning of measurements, ranging from 1.4% to 83%. This indicates that TFWR is highly subject-dependent. Statistically significant correlations were found between the percentage TFWR and McMQ score (r 2 =0.214, p=0.001) as well as FTBUT (r 2 =0.136, p=0.009). No statistically significant correlations were found between TFWR and age, daytime, TMH, and blink frequency., Conclusions: Fluorescein profilometry allows clinicians to follow dynamic changes in the tear film on the entire ocular surface and may be used for qualitative assessment of the tear film dynamics., (Copyright © 2017 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.)

Purpose: To compare clinical tear film break-up time measurements obtained non-invasively, with those measured following minimal and conventional volumes of fluorescein instillation., Methods: Forty-one subjects (20 male, 21 female, mean±SD age 34±11years), with or without dry eye, participated in a prospective cross-over study. Tear film break-up time was measured by the Tearscope Plus™ with fine grid insert. Measurements were made in triplicate, with no fluorescein instillation (NIBUT), then following application of a minimal volume of 1μl fluorescein from the Dry Eye Test™ (mTBUT), and finally with 15-30μl of fluid instilled via a conventional fluorescein strip (TBUT). A fifteen-minute interval between each set of measurements minimised the risk of residual contamination effects., Results: All three techniques displayed statistically significant pairwise correlation (all p<0.001). TBUT values were significantly shorter than both NIBUT (geometric mean 8.6s versus 10.9s, p=0.03) and mTBUT (geometric mean 8.6s versus 10.6s, p=0.03), and demonstrated narrower spread (both p<0.05). No significant differences were detected between NIBUT and mTBUT (all p>0.05)., Conclusions: Tear film break-up time values measured with conventional fluorescein instillation were shortened, while minimal fluorescein instillation and non-invasive methods produced comparable readings. This suggests that minimising instilled volumes can reduce the impact of fluorescein on clinical measurements of tear film stability., (Copyright © 2017 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.)

Purpose: To examine the optimum time at which fluorescein patterns of gas permeable lenses (GPs) should be evaluated., Methods: Aligned, 0.2mm steep and 0.2mm flat GPs were fitted to 17 patients (aged 20.6 ± 1.1 years, 10 male). Fluorescein was applied to their upper temporal bulbar conjunctiva with a moistened fluorescein strip. Digital slit lamp images (CSO, Italy) at 10× magnification of the fluorescein pattern viewed with blue light through a yellow filter were captured every 15s. Fluorescein intensity in central, mid peripheral and edge regions of the superior, inferior, temporal and nasal quadrants of the lens were graded subjectively using a +2 to -2 scale and using ImageJ software on the simultaneously captured images., Results: Subjectively graded and objectively image analysed fluorescein intensity changed with time (p < 0.001), lens region (centre, mid-periphery and edge: p < 0.05) and there was interaction between lens region with lens fit (p < 0.001). For edge band width, there was a significant effect of time (F = 118.503, p < 0.001) and lens fit (F = 5.1249, p = 0.012). The expected alignment, flat and steep fitting patterns could be seen from approximately after 30 to 180 s subjectively and 15 to 105 s in captured images., Conclusion: Although the stability of fluorescein intensity can start to decline in as little as 45 s post fluorescein instillation, the diagnostic pattern of alignment, steep or flat fit is seen in each meridian by subjective observation from about 30s to 3 min indicating this is the most appropriate time window to evaluate GP lenses in clinical practice., (Copyright © 2014 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.)

Purpose: To establish if sodium fluorescein (SFL) dye accumulation within intercellular spaces on the ocular surface contributes to the appearance of superficial punctate corneal staining., Methods: Thirteen subjects bilaterally wore PureVision™ lenses that had been pre-soaked in ReNu MultiPlus® multipurpose solution. After 1h of lens wear, corneal staining with SFL was assessed using a standard slit-lamp technique. Participants who presented with bilateral, corneal staining were selected for further evaluation. A randomly selected eye was rinsed with saline three times. Fellow eyes (control) received no rinsing. After each rinse, the appearance of SFL staining was recorded without any further instillation of the dye. To eliminate any confounding effects of staining due to residual fluorescein in the tear menisci, corneal staining was induced in freshly excised, isolated, rabbit eyes by topical administration of 0.001% PHMB and staining, rinsing and grading were performed as above., Results: Nine out of 13 subjects presented with bilateral diffuse corneal staining (mean grade±SD: 2.4±0.7). The mean staining grades in test and control eyes respectively after each of the three rinses were (1) 2.41±0.41, 2.25±0.69 (p=0.9); (2) 2.34±0.79, 2.1±0.83 (p=0.8); and (3) 1.71±0.65, 1.60±0.79 (p=0.6) there was no significant reduction in staining with rinsing (p>0.05) and no difference was observed between test and control eyes at any sampling-point. Similar observations made in ex vivo rabbit eyes replicated these results., Conclusions: Pooling or accumulation of SFL solution within intercellular spaces does not appear to contribute to the appearance of superficial micropunctate corneal staining., (Copyright © 2011 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.)

Sodium fluorescein ('fluorescein') is widely utilised for the evaluation of ocular surface integrity. It is particularly well suited to this task due to its fluorescent properties and its high visibility at low concentrations. Ocular surface fluorescence observed clinically is affected by a number of factors including concentration of fluorescein, thickness of the fluorescein layer, the wavelength of the exciting light source and whether or not a barrier filter is used as part of the viewing system. In this review we have attempted to provide a critical evaluation of the published literature relating to three potential cellular mechanisms involved in corneal surface fluorescence: surface pooling, uptake by cells and ingress around cells. Despite the widespread adoption of use of fluorescein for the assessment of the ocular surface, we contend that the clinical understanding and interpretation of corneal surface fluorescence is based upon assumption, extrapolation and clinical intuition rather than solid evidence-based science underpinning the basic causative mechanisms of this phenomenon. Further research in order to understand the basic interactions between the ocular surface cells and fluorescein should be made a priority in the fields of optometry and ophthalmology.