Abstract
Pupil blocking force (PBF) can indicate the potential risk of pupil block (PB), which is considered as a main pathogenic factor of primary angle-closure glaucoma (PACG). However, the effect of PB on the PBF under different pupil diameters and iris-lens channel (ILC) distance was unknown. Besides, a simple and practical method to assess PBF has not been reported yet. In this study, 21 finite element models of eyes with various pupil diameters (2.4 mm–2.6 mm) and ILC (2 μm–20 μm) were constructed and were conducted to simulate aqueous humor flow by fluid-solid coupling numerical simulation. PBF in each model was calculated based on the numerical simulation results and was fitted using response surface methodology. The results demonstrated that ILC distance had a more significant effect than pupil diameter on PBF. With the decrease of ILC distance, the PBF increased exponentially. When the reduced distance was lower than 5 μm, the PBF exploded quickly, resulting in a high risk of iris bomb. The PBF also varied with pupil diameter, especially under the condition of narrow ILC. Both ILC distance and pupil diameter could explain more than 97% variation in PBF, and a second-order empirical model has been developed to be a good predictor of PBF. Based on the linear relationship between anterior chamber deformation and PBF, a threshold value of PBF was given to guide clinical decisions. This study could be used to investigate PACG pathological correlation and its pathogenesis, so as to provide a reference value for clinical diagnosis of PACG.
Highlights
Glaucoma is the leading cause of incurable blindness worldwide [1,2,3,4,5]. e most common clinical type in East Asia is primary angle-closure glaucoma (PACG) [6,7,8], which is characterized by a narrow anterior chamber angle (ACA) [9]
Where u1 and u2 are the average velocities in the two surfaces (S1 and S2), p1 and p2 are the pressures in these surfaces, A1 and A2 are their areas, respectively, Z is the vertical distance from S1 to S2, and Hf is the resistance (i.e., pupil blocking force (PBF)) when aqueous humor (AH) flows from S1 to S2 [14, 24]
It was obvious that the main flux of AH from posterior chamber (PC) to AC was at a low velocity
Summary
Received 25 March 2019; Revised 28 July 2019; Accepted 23 August 2019; Published 25 September 2019. The effect of PB on the PBF under different pupil diameters and iris-lens channel (ILC) distance was unknown. PBF in each model was calculated based on the numerical simulation results and was fitted using response surface methodology. E results demonstrated that ILC distance had a more significant effect than pupil diameter on PBF. When the reduced distance was lower than 5 μm, the PBF exploded quickly, resulting in a high risk of iris bomb. E PBF varied with pupil diameter, especially under the condition of narrow ILC. Both ILC distance and pupil diameter could explain more than 97% variation in PBF, and a second-order empirical model has been developed to be a good predictor of PBF. Based on the linear relationship between anterior chamber deformation and PBF, a threshold value of PBF was given to guide clinical decisions. is study could be used to investigate PACG pathological correlation and its pathogenesis, so as to provide a reference value for clinical diagnosis of PACG
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
