Static and Dynamic Measurement of Ocular Surface Temperature in Dry Eyes

Tan, Li; Sanjay, Srinivasan; Morgan, Philip B.

doi:10.1155/2016/7285132

Cited by 16 publications

(17 citation statements)

References 44 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…139 Evaporation causes the tear film to cool and is probably the main source of cooling in evaporative dry eye. 28,140 In those studies, subjects closed their eyes for 3–5 sec to warm the cornea, and then opened them for a 10-second recording. In that interval, the central corneal temperature fell significantly more in dry eye patients than in normals.…”

Section: Images Of Breakup Obtained By Different Methodsmentioning

confidence: 99%

Mechanisms, imaging and structure of tear film breakup

2018

View full text Add to dashboard Cite

Tear film breakup (BU) is an important aspect of dry eye disease, as a cause of ocular aberrations, irritation and ocular surface inflammation and disorder. Additionally, measurement of breakup time (BUT) is a common clinical test for dry eye. The current definition of BUT is subjective; here, a more objective concept of "touchdown" - the moment when the lipid layer touches down on the corneal surface - is proposed as an aid to understanding processes in early and late stages of BU development. Models of BU have generally been based on the assumption that a single mechanism is involved. In this review, it is emphasized that BU does not have a single explanation but it is the end result of multiple processes. A three-way classification of BU is proposed - "immediate," "lid-associated," and "evaporative." Five different types of imaging systems are described, which have been used to help elucidate the processes involved in BU and BUT; a new method, "high resolution chromaticity images," is presented. Three directions of tear flow - evaporation, osmotic flow out of the ocular surface, and "tangential flow" along the ocular surface - determine tear film thinning between blinks, leading to BU. Ten factors involved in BU and BUT, both before and after touchdown, are discussed. Future directions of research on BU are proposed.

show abstract

Section: Images Of Breakup Obtained By Different Methodsmentioning

confidence: 99%

Mechanisms, imaging and structure of tear film breakup

2018

View full text Add to dashboard Cite

show abstract

“…Mathematical as well as experimental studies have established that there is a posterior to anterior temperature gradient in the eye, with temperature close to core body temperature at the retina and approximately 2.5°C lower near the lens 2,3 . Currently, infrared cameras can be mounted on slit lamps and surface temperature of the eye can be readily mapped, with reported ocular surface temperatures of 32–35°C 4,5 . These studies have established the importance of the tear film in adding warmth to the eye surface; surface temperature dissipates by 1°C 10 s after blinking.…”

Section: Introductionmentioning

confidence: 98%

“…2,3 Currently, infrared cameras can be mounted on slit lamps and surface temperature of the eye can be readily mapped, with reported ocular surface temperatures of 32-35°C. 4,5 These studies have established the importance of the tear film in adding warmth to the eye surface; surface temperature dissipates by 1°C 10 s after blinking. Eye temperatures are lower in dry eye 5 and elevated in conditions such as Graves' ophthalmopathy 4 and decrease with treatment.…”

Section: Introductionmentioning

confidence: 99%

“…4,5 These studies have established the importance of the tear film in adding warmth to the eye surface; surface temperature dissipates by 1°C 10 s after blinking. Eye temperatures are lower in dry eye 5 and elevated in conditions such as Graves' ophthalmopathy 4 and decrease with treatment. Prior studies have shown that carotid artery stenosis as well as cavernous-carotid fistulas lower ipsilateral eye temperature by 0.8-1.3°C.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Effects of motion and b‐value on apparent temperature measurement by diffusion‐based thermometry MRI: eye vitreous study

et al. 2020

View full text Add to dashboard Cite

Purpose: To make noninvasive measurements of temperature in the posterior chamber (vitreous) of the eye using diffusion-based thermometry (DBT) magnetic resonance imaging (MRI) and to explain variability in these measurements due to choice of b-value and the effects of motion. Methods: Phantom studies of human vitreous and distilled water were performed using b-values from 0 to 1500 s/mm 2 to determine the liquid-specific calibration factor for vitreous as well as to determine the temperature offsets due to sampling the diffusion curve using three higher routine clinical b-values (b = 0, 500, 1000 s/mm 2) or four lower b-values (b = 0, 200, 400, 600 s/mm 2), thought to be optimized for fluids. Retrospective ROI-based measurements of apparent diffusion coefficient on single slices as well as multi-slice histograms of the eyes were made in six patients with peri-orbital cellulitis and 11 age-matched controls, to assess for temperature changes in the presence of periorbital inflammation. A prospective study of ten repeated measurements of eye temperature using both high and lower b-value sampling was performed in ten asymptomatic volunteers to determine the reproducibility of eye temperature measurements in-vivo as well as to estimate vitreous temperature in the absence of motion. Results: The diffusion coefficient of vitreous (2,088 AE 13 × 10 −6 mm 2 /s) was significantly lower (−1.9%, P < 0.001) compared to distilled water (2,128 AE 12 × 10 −6 mm 2 /s). The calibration factor for temperature measurements of vitreous using DBT is +0.74 AE 0.06°C. Temperature offsets were smaller (<−0.2°C, P < 0.01) when using larger routine clinical b-values to estimate the diffusion coefficient compared to using a series of lower b-values (<−1.0°C, P < 0.001). Two-dimensional singleslice ROI-based measurement showed significant temperature differences (ΔT I-C = 2.5 AE 1.2°C, P < 0.001) between the eyes of patient with peri-orbital cellulitis, higher on the side of inflammation. There was no significant difference in eye temperature when using the 3D histogram (which is likely due to motion averaging as significant slice-to-slice variation was present). However, significant differences in the 3D temperature histograms between the two eyes was observed in one out of six patients. Prospective eye temperature measurements in healthy volunteers showed significant intra-and intersubject variability (33.8-41.6°C), which was caused by eye motion. This resulted in +2.4°C cohortwide elevation in temperature when three b-values were used and +4.7°C when four b-values were used. Using a pattern of elevated temperature at the periphery of the eye to detect motion, eye temperature is the absence of motion was estimated to be 34.5 AE 0.4°C with three higher b-values and 34.6 AE 1.9°C with four lower b-values; this temperature corresponds with prior mathematical simulations of eye temperature as well as boundary conditions. Conclusions: Globe vitreous temperature has been measured noninvasively using DBT MRI. Using routine clinical b-values of b...

show abstract

“…Corneal temperature values of 34 C and above were reported multiple times in literature, in particular as a target threshold for diagnostic purposes. 1,4,17,27,34 Other studies 1,6,49 reported that temperatures in the range 32.0-33.5 C were found across the corneal area. The hysteresis of the sensor was evaluated by temperature swing in the range 33.0 C to 38.0 C, and from 32.0 C to 33.0 C, with a stabilization time of 10 minutes at each 1.0 C step, showing average variations of z8 nm between advancing and receding measurements.…”

Section: Discussionmentioning

confidence: 93%

Contact lenses for continuous corneal temperature monitoring

et al. 2019

View full text Add to dashboard Cite

Temperature variation is a ubiquitous medical sign to monitor ocular conditions including dry eye disease (DED), glaucoma, carotid artery stenosis, diabetic retinopathy, and vascular neuritis. The ability to measure OST in real time is desirable in point-of-care diagnostics. Here, we developed minimally invasive contact lens temperature sensors for continuous monitoring of the corneal temperature. The contact lens sensor consisted of a laser patterned commercial contact lens embedding temperature-sensitive Cholesteric Liquid Crystals (CLCs), which exhibited a fully reversible temperature-dependent color change in the visible spectrum. The contact lens allowed the corneal temperature to be mapped in four key areas, at distances of 0.0, 1.0, 3.0, and 5.0 mm from the pupil's edge. Liquid crystals exhibited a wavelength shift from 738 AE 4 nm to 474 AE 4 nm upon increasing the temperature from 29.0 C to 40.0 C, with a time responsivity of 490 ms and a negligible hysteresis. Readouts were performed using a smartphone, which output RGB triplets associated to temperature values. Contact lens sensors based on CLCs were fitted and tested on an ex vivo porcine eye and readouts were compared with infrared thermal measurements, resulting in an average difference of 0.3 C.

show abstract

Static and Dynamic Measurement of Ocular Surface Temperature in Dry Eyes

Cited by 16 publications

References 44 publications

Mechanisms, imaging and structure of tear film breakup

Mechanisms, imaging and structure of tear film breakup

Effects of motion and b‐value on apparent temperature measurement by diffusion‐based thermometry MRI: eye vitreous study

Contact lenses for continuous corneal temperature monitoring

Contact Info

Product

Resources

About