Opegan hi

Table 2 shows the OVDs used in this study. Opegan^®, Opegan-Hi^®, and Shellgan^® were purchased from Santen Pharmaceutical Co., Ltd (Osaka, Japan). Opelead^® was purchased from Senju Pharmaceutical Co., Ltd (Osaka, Japan). These four products are distributed in Japan. Viscoat^® and Discovisc^® were purchased from Alcon Inc. (Hünenberg, Switzerland), which are distributed worldwide. A 3% hyaluronic acid (HA) solution was prepared by dissolving HA powder (derived from chicken combs, Seikagaku Corp., Tokyo, Japan) in phosphate buffered saline at a final concentration of 3%.Table 2

OVD products investigated in this study

Bland name	Composition	Distributor	Mw (kDa)		Classification [1 (link)]	Apparent viscosity (Pa s)
			HA	CS
Opegan	1% HA with low Mw	Santen	1100	–	Very low viscosity dispersive	5.1
Opelead	1% HA with medium Mw	Senju	1700	–	Medium viscosity dispersive	34.6
3% HA	3% HA with low Mw	Homemade	700	–	Unreported	35.2
Viscoat	3% HA and 4% CS	Alcon	700	20	Medium viscosity dispersive	61.7
Shellgan	3% HA and 4% CS	Santen	700	50	Medium viscosity dispersive	73.0
Discovisc	1.65% HA and 4% CS	Alcon	1600	20	Viscous dispersive	117.0
Opegan-Hi	1% HA with high Mw	Santen	2500	–	Viscous cohesive	62.7

Molecular weights (Mw) of HA and chondroitin sulfate (CS) and apparent viscosity of OVDs at shear rate 1 (1/s) have already been determined [14 (link), 15 (link)]

The investigational products are shown in Table 1 and Figure 1.
The major component of OPEGAN Hi^® 0.85 mL (viscous cohesive; Seikagaku Corporation, Tokyo, Japan) and Healon^® 0.85 mL (viscous cohesive; Abbott Medical Optics Inc, Santa Ana, CA, USA) has the same molecular weight. However, as they are manufactured by different companies, these products come in syringes with different configurations. OPEGAN^® 0.6 mL (very low viscosity dispersive; Seikagaku) and OPEGAN Hi 0.85 mL use the same syringe manufactured by the same company, but the molecular weight of the major component is different. OPEGAN 0.6 mL and OPEGAN^® 1.1 mL (very low viscosity dispersive; Seikagaku) are manufactured by the same company and meet the same standards. However, because they have a different amount, these products come in syringes of different sizes.