A set of device for the in vivo measurement of the pressure difference between the anterior and the posterior chambers (PDAP) was designed to investigate the temporal varying rules of PDAP in the anterior segment of rabbit eyes. A platform was established for the in vivo measurement of PDPA according to the mechanism of joint implement. Rabbit models with high intraocular pressure (IOP) were constructed by means of injecting Carbomer into anterior chamber to increase IOP. The in vivo 24 hours continuous measurements of PDAP were performed for normal rabbit eye and eye with high IOP. The developed device could sensitively response to the small pressure difference in eye. The pressure difference in the normal rabbit eye varied with time, and the variation range during a whole day was 5.84–96.84 Pa which reflected the existence of physiological rule. For the rabbit eye with high IOP, pressure in anterior chamber was higher than that in posterior chamber which was in consistence with the theory of self-adaptation adjustment. The present study indicates that the approaches and device designed in this paper can well implement the measurement of PDAP as well as the temporal varying rules of PDAP in the anterior segment during a whole day.
At present, there are few in vivo experimental studies on anterior chamber flow field, and the relevant technologies are not mature. This study explores the experimental method and key techniques of particle image velocimetry (PIV) for the in vivo measurement of anterior chamber flow field with slow flow velocity in the rabbit with acute intraocular hypertension. The experimental process can be divided into three parts: model construction of rabbit eye with acute intraocular hypertension, in vivo eyeball preparation, and PIV setup. The following key techniques were mainly investigated: the optimal injection strategy of fluorescent particles and the correction strategy for image acquisition errors caused by the effects of image refraction and respiration. The results showed that the best injection method was that 15 μL of fluorescent particles solution was slowly injected into the anterior chamber through the lower part of iris and then the rabbit was released and waited for 13 h. In this way particles were completely distributed in the anterior chamber with the help of the aqueous humor circulation, and then in vivo PIV experiment could be performed. The eyeball should be covered with a square flume filled with ultrasonic coupling gel for the sake of imaging during the experiment. The Maximal Information Coefficient algorithm could be applied to correct the measured results before post-processing calculation. The results indicated that feasible injection strategy of fluorescent particles and the correction strategy for image acquisition are critical to obtain nice experiment effects for the in vivo PIV measurement of anterior chamber flow field in the rabbit with acute intraocular hypertension.
There are so many biomechanical risk factors related with glaucoma and their relationship is much complex. This paper reviewed the state-of-the-art research works on glaucoma related mechanical effects. With regards to the development perspectives of studies on glaucoma biomechanics, a completely novel biomechanical evaluation factor -- Fractional Flow Reserve (FPR) for glaucoma was proposed, and developing clinical application oriented glaucoma risk assessment algorithm and application system by using the new techniques such as artificial intelligence and machine learning were suggested.