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Ramesh S Ve, Varada Vijay, Mredula Devassy, Nijil Sanker, Krithica Srinivasan; Variability of intraocular pressure with increasing collar pressure due to tight tie among obese and normal adults.. Invest. Ophthalmol. Vis. Sci. 2014;55(13):148.
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© ARVO (1962-2015); The Authors (2016-present)
To assess the change in intraocular pressure (IOP) with increasing collar pressure due to necktie in obese and normal subjects.
A total of 60 subjects (20 obese and 40 normal) with no other systemic diseases, underwent ophthalmic evaluation at baseline and post-study, included IOP with applanation tonometer, ultrasonic central corneal thickness (CCT), exophthalmometry and interpupilary distance (IPD) measurements. The study was approved by institutional research and ethics committee and written informed consent was obtained from participants. IOP was measured in 4 different conditions (baseline, tie with slight discomfort, tight tie and loose tie) of tie wear. A custom developed prototype pressure sensor was calibrated and used to measure collar pressure exerted during tie wear and the collar pressure (CP) measurement values ranged from 0 to 1000 units. The sensor was placed at the junction of the tie knot and the custom developed CP estimates were obtained for all subjects across the 4 tie conditions. BMI and body fat index were used to classify group. Intra and inter observer variability, Independent sample t test and ANOVA were appropriately used.
The mean age was 22±2.24 yrs. The IOP during slight discomfort necktie condition was statistically higher than the baseline values in all subjects( 14.18±3.16 and 16.59±3.26 mm HG, p=0.001). IOP showed a decreasing trend after tightening the tie in both groups and it was approaching to the baseline values as the tie was loosened. The mean CP values were 507.10±68.24, 616.54±66.46 and 321.41±95.56 units for the 3 tie conditions respectively, this was statistically significant (ANOVA p < 0.001). There was significant raise in IOP (>2mm HG) at a CP pressure of 507±5 units in the customized sensor. The intra (ICC > 0.9) and inter observer (ICC > 0.9) variability, showed a good agreement for all the parameter measured. The corrected IOP, exophthaolmometry and IPD was found to be a little higher in obese group compared to normal but was not statistically significant (p = 0.080,p = 0.007 and p = 0.037 respectively) and did not vary between baseline and post-study measurements.
Increase in IOP from baseline was observed with the slight discomfort, followed by a dip with tight tie wear. The peak IOP in both study groups was noted for a CP of over 507 units, estimated using a custom developed CP sensors
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