Since the excimer laser treatment for myopia was launched, it has helped many patients to remove their glasses and eliminate the need to wear glasses. However, there are some people who are not so lucky and are temporarily unable to undergo myopia surgery because of a fissure in the retina at the bottom of the eye found during the preoperative examination. What is a retinal fissure, how is it formed, and how harmful is it? In layman’s terms, the retina is a thin layer of membrane-like tissue inside the human eye that is rich in nerve cells and fibers and is the “receiver” in the formation of vision. A normal retina is intact and flat, attached to the inner surface of the wall of the eye. A retinal fissure is a “hole” in the retina, usually based on peripheral retinal degeneration (a degenerative change in the vitreous humor of the retina), and is most often seen in myopic eyes, especially those with high myopia. As the axis of the eye grows in myopic patients, the peripheral retina thins, atrophies, and slowly develops a fissure, or the thinned retina is pulled by the vitreous to form a fissure. Patients with slow onset retinal fissures often have no obvious symptoms, but if there is vitreous traction, they may experience a flashing sensation or dark fluttering shadows. After the formation of retinal fissure, the liquefied vitreous will enter the retina through the fissure and make the retina leave the wall of the eye and fall down to form retinal detachment, at this time the patient can feel a sharp loss of vision, black shadow covering, and even blindness in serious cases, which is a great danger. A thousand miles of dike is destroyed by an anthill, and although the retinal fissure is small, it is a big hidden danger. Patients with myopia, especially those with high myopia, or those who have already had retinal detachment, should go to the ophthalmology department for a comprehensive fundus examination once the above symptoms appear, and if a fissure is found, then fundus retinal laser treatment can be performed to prevent the problem before it happens. Retinal laser, like welding, can form a reinforcement band around the fissure, which strengthens the adhesion of the retina next to the fissure and protects the undetached retina to a large extent, reducing the possibility of retinal detachment, but for those who have retinal detachment or have very poor vitreoretinal conditions, surgery is still needed. Since this technology was introduced in 1996, our ophthalmology department has treated hundreds of patients with peripheral retinal degeneration and fissures without retinal detachment with fundus laser treatment, saving them from surgery and loss of vision.