Abstract: A system for measuring the flow properties of a tear duct, to ascertain its flow resistance, includes a syringe communicating with a cannula to supply liquid to a punctum of an eye, the cannula having a tip to seal to the punctum. A motor is arranged to actuate the syringe. A pressure sensor monitors the pressure of the liquid supplied to the punctum. A monitoring circuit provides an indication of the flow resistance. A feedback circuit controls the motor in accordance with the measured pressure, to maintain a preset liquid pressure, or to ensure that the liquid pressure does not exceed a preset threshold. The system may prevent flow through the other punctum of the eye. If the flow rate of the liquid supplied to the punctum is also monitored, the monitoring circuit is arranged to determine the flow resistance from the pressure and the flow rate.

Abstract: A system for measuring the flow properties of a tear duct, to ascertain its flow resistance, includes a syringe communicating with a cannula to supply liquid to a punctum of an eye, the cannula having a tip to seal to the punctum. A motor is arranged to actuate the syringe. A pressure sensor monitors the pressure of the liquid supplied to the punctum. A monitoring circuit provides an indication of the flow resistance. A feedback circuit controls the motor in accordance with the measured pressure, to maintain a preset liquid pressure, or to ensure that the liquid pressure does not exceed a preset threshold. The system may prevent flow through the other punctum of the eye. If the flow rate of the liquid supplied to the punctum is also monitored, the monitoring circuit is arranged to determine the flow resistance from the pressure and the flow rate.

Abstract: A system for measuring the flow properties of a tear duct, to ascertain its flow resistance, includes a syringe communicating with a cannula to supply liquid to a punctum of an eye, the cannula having a tip to seal to the punctum. A motor is arranged to actuate the syringe. A pressure sensor monitors the pressure of the liquid supplied to the punctum. A monitoring circuit provides an indication of the flow resistance. A feedback circuit controls the motor in accordance with the measured pressure, to maintain a preset liquid pressure, or to ensure that the liquid pressure does not exceed a preset threshold. The system may include means to prevent flow through the other punctum of the eye. If the flow rate of the liquid supplied to the punctum is also monitored, the monitoring circuit is arranged to determine the flow resistance from the pressure and the flow rate.

Abstract: An ophthalmic sizing device includes a sizing tube or set of such sizing tubes for use in determining a correct size of a bypass tube required in lacrimal surgery, each sizing tube having a flanged end at one end of a longitudinal length of tubing, the remaining end of the tubing distal to the flanged end having a series of ruled markings longitudinally along and towards the flange end. When used, a set of sizing tubes includes tubes having at least two relatively different absolute longitudinal lengths of tubing; and/or diameter flanges. The device can be in the form of a dilator having a sizing section. The use of such sizing devices allows the length of an ophthalmic bypass tube to be determined that leaves the tip of the bypass tube, when in situ, to protrude an optimally desired distance beyond the outer (lateral) nasal wall and into the nasal cavity of each particular patient, while remaining clear of the midline septum.

Abstract: An ophthalmic sizing device includes a sizing tube or set of such sizing tubes for use in determining a correct size of a bypass tube required in lacrimal surgery, each sizing tube having a flanged end at one end of a longitudinal length of tubing, the remaining end of the tubing distal to the flanged end having a series of ruled markings longitudinally along and towards the flange end. When used, a set of sizing tubes includes tubes having at least two relatively different absolute longitudinal lengths of tubing; and/or diameter flanges. The device can be in the form of a dilator having a sizing section. The use of such sizing devices allows the length of an ophthalmic bypass tube to be determined that leaves the tip of the bypass tube, when in situ, to protrude an optimally desired distance beyond the outer (lateral) nasal wall and into the nasal cavity of each particular patient, while remaining clear of the midline septum.

Abstract: A tear-duct drain includes a hollow rigid tube which is elongated and has a first flange at one extremity thereof. A flexible, resilient and collapsible second flange is bonded to the tube at a predetermined distance away from, and so providing a leading edge at, the opposite extremity of the tube.

Abstract: A tear-duct drain includes a hollow rigid tube which is elongated and has a first flange at one extremity thereof. A flexible, resilient and collapsible second flange is bonded to the tube at a predetermined distance away from, and so providing a leading edge at, the opposite extremity of the tube.