*Department of Ophthalmology, University of Southern California School of Medicine, Doheny Eye Institute, Los Angeles, California, U.S.A. and daggerDepartment of Ophthalmology, Escola Paulista de Medicina, São Paulo, Brazil.
J Glaucoma. 1995 Aug;4(4):274-80.
These experiments were designed to analyze the relationship between glaucoma drainage implant surface area and the physiological function of the surrounding encapsulation.
Three sizes of Baerveldt implants were studied. Commercially available 200 mm devices were trimmed to reduce surface area to 100 and 50 mm (one side), respectively. Five samples of each size of device were studied 3 weeks after implantation in normal rabbit eyes by perfusing the drain tubes in vivo using a micromanometric system allowing precise control of flow rates. Additional eyes were analyzed at 12 weeks. Resistance to flow was calculated using Poiseuille's equation after at least three different flow rate readings for each implant, and a linear regression line was plotted for each eye. Flow rates at the pressures of 10, 15, 20, and 25 mm Hg were standardized by slope calculation and mean flow rate values for each size of implant compared statistically. Calculated flow per unit area (hydraulic conductivity) was calculated for each sized implant.
The perfusion flow tests demonstrated statistically significant differences for the values of resistance to flow and flow through the implants for the three surface areas tested. The 200 mm implants had higher flow rates and lower resistance values. A statistically significant inverse correlation was found between the surface area of the implant and the resistance to flow (p = 0.0002). A statistically significant direct correlation was also found between the surface area of the implant and the values of flow rates (p = 0.0002) through the capsules. Hydraulic conductivity of the capsules was virtually identical for all three sizes of implants tested.
The results demonstrate a direct relationship between the surface area of glaucoma implants and the filtering capacity of their surrounding capsules.
本实验旨在分析青光眼引流植入物表面积与周围包裹组织的生理功能之间的关系。
研究了三种尺寸的 Baerveldt 植入物。将市售的 200mm 装置裁剪至分别为 100 和 50mm（单侧）的表面积。将三种尺寸的装置各 5 个样本分别植入正常兔眼 3 周后，通过体内微压测量系统对引流管进行灌流，以精确控制流速。对另外一些眼进行 12 周分析。对每个植入物至少进行三次不同流速测量后，用泊肃叶方程计算流动阻力，并为每只眼绘制线性回归线。通过斜率计算将压力为 10、15、20 和 25mmHg 时的流速标准化，并对每个尺寸的植入物的平均流速值进行统计学比较。为每个尺寸的植入物计算单位面积的计算流量（水力传导率）。
灌注流量测试显示，三种表面积测试的植入物的流动阻力和流量值存在统计学差异。200mm 植入物具有更高的流速和更低的阻力值。植入物表面积与流动阻力呈统计学上的负相关（p=0.0002），与通过胶囊的流速值呈统计学上的正相关（p=0.0002）。三种尺寸的植入物的胶囊水力传导率几乎相同。
结果表明，青光眼植入物表面积与周围包裹组织的过滤能力之间存在直接关系。
