A simplified xeroscope for the noninvasive measurement of tear break-up time

@#<p style="text-align: justify;"><strong>OBJECTIVE:</strong> To develop and validate a noninvasive method for measuring tear break-up time (NIBUT) using readily available materials and comparing it to the standard fluorescein tear break-up time (TBUT) assessment.</p> <p style="text-align: justify;"><strong>METHODS:</strong> A prototype xeroscope was made from an ordinary round plastic lid. At its inner lining, a fluorescent green sticker paper printed with black circular concentric grid pattern was fixed to simulate modified placido rings on the precorneal reflection. A central rectangular cut-out measuring 2 cm x 1 cm was made into the base frame serving as the viewfinder for the device through which the precorneal grid reflection was observed. A 30-LED blue light strip was fixed in the inner rim of the lid using a double-sided adhesive tape and was powered by a multi-voltage AC-DC power adapter set at 6-volts at 350mA (2 watts). The prototype device was tested on fifty (50) patients (100 eyes), aged 21 to 65 years old, with no apparent ocular surface disorders and eyelid abnormalities. Measurement of NIBUT was done on both eyes using the prototype xeroscope followed by fluorescein TBUT measurement. The two values were compared and their correlation determined by linear-regression.</p> <p style="text-align: justify;"><strong>RESULTS:</strong> Fifty (50) patients (100 eyes) were enrolled into the study. The mean age was 48.52 years (range 21 to 62 years). The mean NIBUT for both eyes was 20.10 secs, ranging from 11.56 to 36.17 secs, and the mean TBUT was 18.70 secs, ranging from 10.20 to 30.40 secs. The mean difference between NIBUT and TBUT was 1.40 sec. Regression analysis revealed a strong positive linear correlation between the 2 measurements with a computed R-squared value of 0.9697.</p> <p style="text-align: justify;"><strong>CONCLUSION:</strong> The noninvasive technique using the prototype device provided a good alternative approach for measuring tear film stability without disturbing normal tear physiology and dynamics at at fraction of the cost of current commercially-available xeroscopes and tearscopes.</p>

Assessment of Tear Lipid Layer after Treatment by an Infrared Instrument

PURPOSE: We performed this study to evaluate the influence on tear film of infrared instrument by observing the morphologic change of the tear lipid layer and tear break-up time by Tearscope(R). METHODS: The subjects were 52 eyes from 26 people. After infrared hyperthermic therapy, we analyzed the change of the tear lipid layer by Tearscope(R) at 10 minutes, 6 hours, and 12 hours. We also observed the subjective symptoms of change related to dry eye syndrome and tear break-up time. RESULTS: Of the 26 normal cases, 20 were men and 6 were women. The mean age was 26.4 +/- 1.9 years. The subjective symptoms improved and the tear lipid layer showed a decrease of color fringe yellow-brown and color fringe multiple colors type, and an increase of waves and closed meshwork type 10 minutes and 6 hours following infrared treatment. Tear break-up time was also prolonged from preoperative value of 10.0 +/- 2.4 seconds to 11.0 +/- 2.7 and 11.1 +/- 2.9 seconds at 10 minutes and 6 hours, respectively, after infrared treatment, but this effect did not persist after 12 hours. Schirmer test value did not show significant change. No complication related to infrared treatment was noted. CONCLUSIONS: Infrared treatment may be considered a possible method of treating dry eye syndrome by increasing the stability of the tear lipid layer.

Characteristics of Tear Lipid Layer Patterns on Tearscopy and Lipid Layer Thickness

This study is to evaluate thickness of lipid layer, NIBUT (non-invasive tear film break-up time), BUT and Schirmer value according to tearscopic pattern of lipid layer.The subjects are seventy-one eyes from seventy-one people without ocular diseases.The pattern of lipid layer is observed by Tearscope(r) (Keeler, U.K.)and the thickness of lipid layer is measured by interference generated from slit lamp microscope.The thickness of lipid layer, NIBUT and BUT are respectively measured three times and averaged.In the case of the pattern of lipid layer, eighteen eyes have the close meshwork type, twenty-nine eyes have the wave type, fifteen eyes have the amorphous type and nine eyes have the color fringe type.The average value of the thickness of lipid layer, NIBUT, BUT and Schirmer test were respectively 29.3 nm, 25.9 seconds, 12.0 seconds, 18.6 mm for close meshwork;47.2 nm, 33.6 seconds, 12.5 seconds, 16.9 mm for wave;66.2 nm, 39.7 seconds, 14.9 seconds, 18.7 mm for amorphous;and 74.4 nm, 30.9 seconds, 13.9 seconds, 18.9 mm for color fringe.The thickness of lipid layer was different significantly among the patterns.NIBUT showed significant difference between close meshwork and wave, and between close meshwork and amorphous.The Cronbach alpha, reproducibility of the test, is 0.84 in the thickness of lipid layer, 0.64 in NIBUT, 0.76 in BUT and 0.94 in Schirmer test.The reproducibility of the pattern of lipid layer observed by Tearscope(r) is 95.8%.

Characteristics of Tear Lipid Layer on Tears copy in Dry Eye Symptom and Non-Dry Eye Symptom Group

The lipid layer plays a important role in tear film stability. And several studies have reported the differences of lipid layer pattern and tear film break up time between normal and dry eye. To determine the availability of Tearscope(Keeler, UK), we observed the characteristics of lipid layer and compared non-invasive break up time(NIBUT) to invasive break up time(IBUT) in dry eye symptom and non-dry eye symptom group. By questionnaire, we selected the dry eye symptom(94 eyes in 47 persons) and the non-dry eye symptom(112 eyes in 56 persons) group. We observed lipid layer pattern and color by Tearscope, and measured NIBUT of Tearscope and IBUT of fluorescein solution. In the lipid layer, the dry eye symptom group had brown-yellow(about 112 nm) and uneven pattern. But, the non-dry eye symptom group represented amorphous(about 94 nm) and even pattern. In NIBUT, the dry eye symptom group had 9.57+/-11.40sec and the non-dry eye symptom group represented 27.42+/-20.15sec. In IBUT, two groups had 6.38+/-4.45sec and and 13.02+/-8.41sec, respectively. In conclusion, Tearscope is available in diagnosis and treatment in dry eye and also in diagnosis of tear lipid layer disorder.