A new method for tear film stability analysis using videokeratography

Gotō, Tomoko; Zheng, Xiaodong; Klyce, Stephen D.; Kataoka, Hideki; Uno, Toshihiko; Karon, Mike; Tatematsu, Yoshiyuki; Bessyo, T; Tsubota, Kazuo; Ohashi, Yuichi

doi:10.1016/s0002-9394(02)02221-3

Cited by 123 publications

(85 citation statements)

References 10 publications

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“…Several non-invasive tear break-up time tests have been developed to evaluate tear film stability. Consecutive topographic image recording such as a tear film stability analysis system (TSAS) has been applied to assess tear film stability (Goto et al 2003;Kojima et al 2004). This technique does not have the intrinsic invasiveness of fluorescein instillation; however, subjects are forced to keep their eyes open, which may result in reflex tearing that can influence aqueous tear-sourced data subsequently obtained (Anonymous 2007c).…”

Section: Introductionmentioning

confidence: 99%

Effect of non‐invasive tear stability assessment on tear meniscus height

Koh

Ikeda

Watanabe

et al. 2014

Acta Ophthalmologica

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ABSTRACT.Purpose: To investigate the effect of non-invasive tear stability assessment with forced eye opening on the lower tear meniscus. Methods: Twenty-three eyes of 23 patients with aqueous-deficient dry eye and 23 eyes of 23 normal subjects were enrolled. All subjects underwent imaging with a Keratograph 5M equipped with a modified tear film scanning function. Lower tear meniscus images were captured, and tear meniscus height (TMH) was measured with an integrated ruler before and after non-invasive Keratograph break-up time (NIKBUT) measurements in each subject. Subjects were instructed to keep their eyes open as long as possible during NIKBUT measurements, and the recording was discontinued at the next blink. Results:The TMH values of the normal and dry eye groups were 0.20 AE 0.05 mm and 0.14 AE 0.03 mm, respectively, at baseline. The TMH values of dry eyes were significantly smaller than those of normal eyes (p < 0.001). Significant increases in TMH values were observed in both normal (0.10 AE 0.12 mm) and dry eyes (0.04 AE 0.09 mm) with the NIKBUT measurement (p < 0.001, p = 0.039). A moderate negative correlation was observed between increased TMH and baseline TMH in dry eyes (r = À0.44, p = 0.03), whereas no correlation was observed in normal eyes (r = 0.04, p = 0.85). Conclusions: Forced eye opening required for the non-invasive tear stability assessment influences the TMH measurement possibly due to reflex tear secretion, even in patients with aqueous-deficient dry eye. TMH should be assessed before tests that require forced eye opening.

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Section: Introductionmentioning

confidence: 99%

Effect of non‐invasive tear stability assessment on tear meniscus height

Koh

Ikeda

Watanabe

et al. 2014

Acta Ophthalmologica

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“…In the investigation of tear film stability, this technique was used as a noninvasive and objective method for the clinical assessment of tear film stability at a frequency of 1 Hz. [6][7][8] In other studies, the changes of higher order ocular surface wavefront aberrations were investigated in normal and dry eyes. 3,9 The higher order aberrations were found to first decrease immediately after a blink, reaching a minimum 6 s post-blink, and then to increase steadily.…”

Section: Introductionmentioning

confidence: 99%

Dynamics of ocular surface topography

Zhu

Collins

Iskander

2006

Eye

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Purpose To investigate fluctuations in the ocular surface, we used high-speed videokeratoscopy (50 Hz) to measure the dynamics of the ocular surface topography. Methods Ocular surface height difference maps were computed to illustrate the changes in the tear film in the inter-blink interval. Topography data were used to derive the ocular surface wavefront aberrations up to the fourth radial order of the Zernike polynomial expansion. We examined the ocular surface dynamics and temporal changes in the ocular surface wavefront aberrations in the inter-blink interval. Results During the first 0.5 s following a blink, the ocular surface height at the upper edge of the topography map increased by about 2 lm. Temporal changes occurred for some ocular surface wavefront aberrations and appeared to be related to changes in the distribution of tear film. Conclusion In the clinical measurement of ocular surface topography using videokeratoscopy or optics of the eye using wavefront sensors, care should be taken to avoid the initial tear film build-up phase following a blink to achieve more consistent results.

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“…Some of them are capable of continuous recording of the eye, fact that allows the analysis of dynamic changes in the corneal surface [1,2]. However, none of available devices allows full control of the camera and processing algorithms.…”

Section: Introductionmentioning

confidence: 99%

Open-access operating algorithms for commercial videokeratographer and improvement of corneal sampling

et al. 2013

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We present an algorithm to process images of reflected Placido rings captured by a commercial videokeratoscope. Raw data are obtained with no Cartesian to polar coordinates conversion, thus avoiding interpolation and associated numerical artefacts. The method provides a characteristic equation for the device and is able to process around 6 times more corneal data than the commercial softwares. Our proposal allows complete control over the whole process from the capture of corneal images until the computation of curvature radii.

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A new method for tear film stability analysis using videokeratography

Cited by 123 publications

References 10 publications

Effect of non‐invasive tear stability assessment on tear meniscus height

Effect of non‐invasive tear stability assessment on tear meniscus height

Dynamics of ocular surface topography

Open-access operating algorithms for commercial videokeratographer and improvement of corneal sampling

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