China 
Africa 
Explore chapters and articles related to this topic
Light safety
Published in Pablo Artal, Handbook of Visual Optics, 2017
Conditions and procedures one can apply laser technology to Eyelid growths, including lid cancersHistoplasmosisCentral serous retinopathyLASIKCataract surgeryGlaucoma surgeryDiabetic retinopathyMisdirected eye lashes (trichiasis)Opening up or treating blockage of the opening to the tear ducts (lacrimal punctum)Benign (noncancerous) growth on the tissue that covers the surface of the white part of the eye and may grow onto the cornea (pterygium)Increased eye pressure (glaucoma)Prevention and treatment of attacks of acute glaucoma (laser iridotomy)Retinal tears and detachment treatmentDiabetic retinopathyTreatment of cancer of the eye (such as retinoblastoma)Open-angle glaucoma
The tear turnover and tear clearance tests – a review
Published in Expert Review of Medical Devices, 2018
Izabela K. Garaszczuk, Robert Montes Mico, D. Robert Iskander, Alejandro Cerviño Expósito
To achieve tear homeostasis, the LFU ensures the delivery of supportive and protective substances, formation of tear film, and clearance of pro-inflammatory or toxic factors through the nasolacrimal drainage system [2–4]. Blinking generates a pumping effect on the nasolacrimal drainage system to draw tears into the lacrimal sac and plays a key role in tear dynamics by spreading, mixing, and distributing the tears and clearing cellular and other debris [4–6]. Spontaneous blinks are thought to be modified by reflex inputs from the ocular surface and inputs from the higher centers. The blink cycle consists of the blink itself and the blink interval, during which evaporative water loss occurs. Rapid flow of tears into the canaliculi can be observed during the first few seconds following the blink [7]. The lacrimal drainage capacity increases with increasing blink rate and aging [8]. When the excess fluid is present in the conjunctival sac, the expansion of the lacrimal sac serves as to draw in the excess fluid for many seconds following the blink, resulting in a steady flow toward the lacrimal punctum, called the Krehbiel flow [4,9]. Since the canaliculi can normally transport more fluid in one blink that is attributed to normal, non-reflex tear secretion, the drainage system is operating nearly empty most of the time in normal conditions. Blink rate drops after topical anesthesia [10] and following LASIK surgery [11].