Fluorophotometric Assessment of Tear Turnover Under Rigid Contact Lenses

Kok, J. H. C.; Boets, E. P. M.; Best, J. A. Van; Kijlstra, A.

doi:10.1097/00003226-199211000-00005

Cited by 36 publications

(25 citation statements)

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“…Based on clinical and anecdotal feedback, consensus was reached on the ideal settling time being 20 minutes; the rating of discomfort on a 5 point scale, which has previously been shown to sufficiently differentiate between comfort states, without scale grades being redundant 1 ; white diffuse light evaluation of centration and coverage, with recording linked to issues that would affect clinical management such as crossing the limbus or the optic zone is encroaching across the pupil; and movement on blink which is critical to healthy ocular physiology. 19,21 Fluorescein assessment was concluded to be best evaluated with the GP lens centred, using lid manipulation if necessary, using a ± 2 grading system in the four principal meridians, Interestingly, simulated fluorescein patterns were subjectively graded as significantly less intense than actual photographs in each zone and this was confirmed objectively. In addition, the correlation between the objective quantification of the real and simulated fluorescein patterns was significant, but only just.…”

Section: Discussionmentioning

confidence: 99%

“…While soft lenses with limited mobility have been shown to have a more negative impact on ocular physiology than well fitting soft lenses, 20 this is not well researched for GPs. This is probably because tear exchange beneath an GP is typically 15-16% compared to 1-2% for soft lenses, 19,21 although tear mixing with differing amounts of lens movement does not seem to have been examined.…”

mentioning

confidence: 99%

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Consensus on recording of gas permeable contact lens fit

Wolffsohn¹,

Worp²,

Brabander³

2013

Contact Lens and Anterior Eye

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Purpose:To develop a new schematic scheme for efficiently recording the key parameters of gas permeable contact lens (GP) fits based on current consensus. Methods:Over 100 established GP fitters and educators met to discuss the parameters proposed in educational material for evaluating GP fit and concluded on the key parameters that should be recorded. The accuracy and variability of evaluating the fluorescein pattern of GP fit was determined by having 35 experienced contact lens practitioners from across the world, grading 5 images of a range of fits and the topographer simulation of the same fits in random order using the proposed scheme. The accuracy of the grading was compared to objective image analysis of the fluorescein intensity of the same images. Results:The key information to record to adequately describe the fit of an GP was agreed as: the manufacturer, brand and lens parameters; settling time; comfort on a 5 point scale; centration; movement on blink on a ±2 scale; and the Primary Fluorescein Pattern in the central, mid-peripheral and edge regions of the lens averaged along the horizontal and vertical lens axes, on a ±2 scale. On average 50-60% of practitioners selected the median grade when subjectively rating fluorescein intensity and this was correlated to objective quantification (r=0.602,p <0.001). Objective grading suggesting horizontal median fluorescein intensity was generally symmetrical, as was the vertical meridian, but this was not the case for subjective grading. Simulated fluorescein patterns were subjectively and objectively graded as being less intense than real photographs (p<0.01).Conclusion: GP fit recording can be standardised and simplified to enhance GP practice.

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Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

Consensus on recording of gas permeable contact lens fit

Wolffsohn¹,

Worp²,

Brabander³

2013

Contact Lens and Anterior Eye

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“…8 A poor postlens tear exchange, especially with soft contact lenses, leads to the buildup of inflammatory cells, metabolic byproducts, and debris in the postlens tear film that may cause adverse ocular responses. 9,10,14 Supporting this theory is the fact that gas-permeable lenses demonstrate high levels of tear mixing similar to physiologic tear turnover 17 as well as fewer serious ocular complications commonly seen with soft lens extended wear. 2 The apparent difference between rigid and soft lenses, linked to variations in size and material properties, lies in their dissimilar capabilities to mix and replenish the postlens tear film.…”

Section: Adverse Events During Contact Lens Wearmentioning

confidence: 96%

Accounting for Ethnicity-Related Differences in Ocular Surface Integrity as a Step Toward Understanding Contact Lens Discomfort

Chan

Svitova

Lin³

2017

Eye &Amp; Contact Lens: Science &Amp; Clinical Practice

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Contact lens discomfort is a common problem that can lead to unsuccessful or limited contact lens wear. Although many factors may contribute to contact lens discomfort, limited research has explored the influence of ethnicity-related differences in the anatomy and physiology of the ocular surface. Therefore, we performed a search of the literature in PubMed using key words related to “ocular surface” paired with the terms “race” and “ethnicity.” The goal of this review was to determine potential areas of research regarding ethnicity differences, particularly between Asian and non-Asian eyes, in ocular surface integrity to advance our understanding of contact lens discomfort.

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“…30,32,89---91,125 These latter values are broadly equal to the tear turnover time with no lens on the eye. 30 Interestingly, McGrogan 109 also found that micro-beads clear from the pre-corneal tear film within 5 min.…”

Section: Published Datamentioning

confidence: 99%

“…Tear turnover time (T 95 ) averages at 30 min for soft lenses, 28,30,31,33,110,124 as opposed to approximately 5 min for rigid lenses. 30,32,89---91,125 These latter values are broadly equal to the tear turnover time with no lens on the eye.…”

Section: Published Datamentioning

confidence: 99%

Tear exchange and contact lenses: A review

Müntz

Subbaraman

Sorbara

et al. 2015

Journal of Optometry

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Tear exchange beneath a contact lens facilitates ongoing fluid replenishment between the ocular surface and the lens. This exchange is considerably lower during the wear of soft lenses compared with rigid lenses. As a result, the accumulation of tear film debris and metabolic by-products between the cornea and a soft contact lens increases, potentially leading to complications. Lens design innovations have been proposed, but no substantial improvement in soft lens tear exchange has been reported. Researchers have determined post-lens tear exchange using several methods, notably fluorophotometry. However, due to technological limitations, little remains known about tear hydrodynamics around the lens and, to-date, true tear exchange with contact lenses has not been shown. Further knowledge regarding tear exchange could be vital in aiding better contact lens design, with the prospect of alleviating certain adverse ocular responses. This article reviews the literature to-date on the significance, implications and measurement of tear exchange with contact lenses.

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Fluorophotometric Assessment of Tear Turnover Under Rigid Contact Lenses

Cited by 36 publications

References 0 publications

Consensus on recording of gas permeable contact lens fit

Consensus on recording of gas permeable contact lens fit

Accounting for Ethnicity-Related Differences in Ocular Surface Integrity as a Step Toward Understanding Contact Lens Discomfort

Tear exchange and contact lenses: A review

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