I. Characteristics of high myopia Asia is a region with a high prevalence of myopia worldwide, and China is a large myopic country, and the prevalence of myopia is increasing among the younger generation. High myopia is defined as a degree of myopia greater than 600 degrees. In addition to myopia, patients with high myopia are often combined with a number of other eye conditions: younger cataract development, relaxation of the lens suspensory ligament, accelerated vitreous liquefaction degeneration, dilated and thinning posterior sclera, thinning retinal choroid, and a greatly increased risk of retinal degeneration, fissures, retinal detachment, and macular degeneration (atrophy, degeneration, neovascularization or hemorrhage) II. Benefits of cataract surgery Patients with high myopia, wearing glasses with the bottom of a beer bottle, have poor visual quality and poor quality of life, and their vision is even worse when combined with cataract. Cataract ultrasound surgery not only removes the cataract, but also allows patients to remove their thick glasses. The quality of vision is better and clearer under the same eye conditions. Of course, due to the problem of high myopia, cataract surgery has its own characteristics and precautions.
1. Measurement of IOLs Patients with high myopia have relatively poor fixation ability due to the combination of scleral chylomalacia and cataract surgery, so the error of the preoperative measurement of the eye axis is large, which leads to the increase of the deviation of the implanted IOLs and the large deviation of the actual prescription and the expected prescription after surgery. Of course, if there is a large deviation, there is no need to worry, and you can consider lens correction or IOL replacement.
2. Cataract surgery characteristics and precautions a. Cataracts combined with high myopia are often nuclear cataracts. If the cataract is obvious and the nucleus is hard, the ultrasound energy required during surgery is larger, the probability of corneal edema increases in the early postoperative period, and the recovery of vision after surgery is slightly slower.
b. In highly myopic patients, the lens suspensory ligament is relaxed and the vitreous liquefaction is obvious, so the chance of suspensory ligament abnormality and rupture and incomplete posterior capsule increases intraoperatively, making surgery more difficult. If this condition is combined, intraoperative capsular bag tension ring implantation and suture suspension of the IOL may be performed. It is also possible that for safety reasons, the IOL will not be implanted during the same period and will be implanted at the next surgery.
c. In highly myopic patients with dilated posterior sclera and thinning retina and choroid, the chance of intraoperative and postoperative retinal and choroidal hemorrhage is significantly increased compared to normal subjects. Preoperative prophylactic use of hemostatic drugs may be appropriate.
d. Patients with high myopia are at a much higher risk of combined macular degeneration, so the best corrected visual acuity after cataract surgery needs to be determined by the condition of their fundus (retina).
e. Patients with high myopia are at increased risk of retinal degeneration, fissures, and retinal detachment, so it is not uncommon for retinal detachment to occur after cataract surgery if their own retina is of poor quality. This has nothing to do with cataract surgery itself, and regular dilated pupil examinations of the fundus are still needed after surgery to detect lesions early.