With the continuous improvement of cataract ultrasound emulsion surgery, more and more cataract patients have obtained satisfactory vision through perfect and precise surgery, but some patients complain to the doctor after the surgery that their vision is clear, but their eyes feel uncomfortable, dry, astringent, and a bit burning, and sometimes they feel as if there is a foreign object poking their eyes, and they cannot open their eyes in the morning. Some patients also complain that they can watch TV clearly at first, but it becomes blurry after watching for a long time. Why did they have this symptom before the incision but after the incision, and why did the symptom worsen instead of decrease after using antibiotics for a long time? It turns out that this symptom is actually a dry eye symptom and physical condition that some patients experience in the short term after cataract surgery, which we call symptomatic dry eye. Research data shows that more than 30% of patients have dry eye symptoms after cataract surgery, but most of them can recover after a period of time after surgery. Even for patients with some degree of pre-existing dry eye, ultrasound emulsification is still a relatively safe procedure and generally does not cause recurrent severe dry eye.
So why do these symptoms occur? After cataract surgery, the patient’s tear film will change significantly, especially on the first and second postoperative days, the stability of the tear film will decrease significantly, the tear film rupture time will be shortened significantly, the degree of corneal fluorescein staining and tear secretion will increase significantly; at the same time, the morphology of the lipid layer of the tear film will be damaged significantly, and the tear secretion will not basically return to the preoperative level until 7 days after surgery, due to: (1) surface anesthetics caused punctate detachment of corneal epithelium and decreased tear film stability.
(2) Intraoperative mechanical damage to the corneal epithelium, postoperative inflammatory reaction, tissue edema, wound healing and local bulging of the surgical incision all affect the adhesion function of the tear film mucus layer to the ocular surface epithelium, resulting in decreased tear film stability.
(3) Transparent corneal incision causes impairment of acetylcholine and cholinesterase transport in the nerve fibers around the incision, resulting in local corneal hyperalgesia.
(4) Frequent use of preservative-containing eye drops by patients in the early postoperative period causes prompt retention of the preservative in the conjunctival capsule, which has a sustained toxic effect on the corneal epithelium and changes the permeability of the cells, thereby affecting tear film function.
(5) The application of glucocorticoid drops after ultrasonic cataract aspiration will promote the decomposition of fat and protein, which will produce certain damage to the stability of the tear film, resulting in a shortened tear film rupture time and a decrease in tear secretion.
(6) Many patients with senile cataract are also combined with diabetes. Diabetic patients have poor tear film function and are susceptible to dry eye disease.
Generally speaking, the symptoms of dry eye after cataract surgery are mostly mild dry eye (no damage to the cornea), so there is no need to worry too much. As long as the diagnosis is clear, use local drops of artificial tears, take vitamin A and B vitamins orally, and develop good habits, such as getting enough sleep, eating more fruits rich in vitamin A and vitamin C, applying hot compresses to both eyes, blinking more often, and reducing the time spent looking at the computer. After surgery, we insist on using artificial tears four times a day, the purpose of which is to replenish water, moisten the eye surface and produce a mucus absorbent solution to cover the eye surface, thus prolonging the tear film rupture time and improving the patient’s discomfort. Most patients experience relief within six months postoperatively.