Frequent squinting is a bad eye habit, and patients may experience an increase in astigmatism and also an increase in myopia. The reason why patients squint is because through the principle of small hole imaging, it can make the image presented by external light on the retina clearer, thus temporarily improving the quality of vision of patients. If the patient squints for a long period of time, the eyelids will exert pressure on the cornea, leading to gradual deformation of the cornea and deepening of astigmatism. In addition, squinting patients are also prone to visual fatigue, so the patient’s myopia will accelerate the development of myopia, and it is easy to form a high degree of myopia. It is recommended that patients who squint to see things should consult a doctor promptly to assess their condition and follow the doctor’s instructions for treatment.