Patient's question:
The patient underwent cataract surgery today, but during the procedure, bleeding occurred in the eye, which prevented the surgery from proceeding further. As a result, the patient's vision deteriorated rapidly. However, the hospital merely informed our family that this was a surgical complication. We are wondering whether this is a medical accident or truly a complication. Before the surgery, the patient underwent various tests, all of which were normal. The family wants to understand what potential complications might occur with cataract surgery.Doctor's answer:
Cataracts are called cataracts when the lens of the eye becomes cloudy. Aging, genetics, metabolic disorders, trauma, radiation, poisoning, and local malnutrition can cause lens capsule damage, increasing its permeability, losing its barrier function, or leading to lens metabolic disorders, causing lens protein to denature and form opacity. The main symptom of cataracts is visual impairment, which is related to the degree and location of lens opacity. Severe cataracts can lead to blindness. Cataracts are classified according to their causes into age-related (senile), traumatic, complicated, metabolic, toxic, radiation, developmental, and secondary cataracts, among others. Generally, surgery is the only way to treat cataracts. Due to the application of surgical microscopes, microsurgical instruments, and intraocular lenses, as well as improvements in suture materials and local anesthesia methods, cataract surgery has made significant progress in the past 30 years. Currently, cataract extraction is the most commonly used treatment, with an intraocular lens or glasses or contact lenses implanted after surgery to correct vision. Today's cataract surgery replaces the lens, which is much simpler and safer than traditional surgery. As long as the elderly are in good health and do not have contraindications for surgery such as hypertension, hyperglycemia, or hyperlipidemia, the surgery can be performed. A single surgical procedure can be completed in just 7 or 8 minutes. There are no special dietary restrictions after cataract surgery, and patients are not particularly restricted in their activities or daily lives, but they should wear an eye patch for several days and avoid accidentally injuring the eye due to exercise, work, or playing with children. Postoperatively, follow the instructions to use eye drops and oral medications, and return to the ophthalmology outpatient clinic for examination. Vision usually improves gradually soon after surgery, and reading glasses may be prescribed if needed. If there is a sudden decrease in vision, eye pain, or accidental injury, it is necessary to return to the hospital for examination immediately.1. What are cataracts? Cataracts are a condition where the lens inside the eye becomes cloudy, changing from transparent to opaque, obstructing light from entering the eye and thus affecting vision. In the early stages, the cloudiness has little impact on vision, but it gradually worsens, significantly affecting vision and even leading to blindness. Worldwide, cataracts are the leading cause of blindness. Currently, approximately 20 million people worldwide are blind due to cataracts, and another 100 million cataract patients require surgery to restore their vision. In most African and Asian countries, cataracts account for at least half of all blindness. According to surveys in China, cataracts are also the leading cause of blindness in the country. Cataracts have many causes: some are congenital cataracts (more common in children), eye trauma can also cause cataracts, and certain internal diseases can also lead to cataracts, such as diabetes and nephritis. Additionally, complicated cataracts can occur, but most cases and patients are related to aging. The incidence of senile cataracts in people aged 50–60 is 60–70%, and it reaches 80% in those over 70, with almost 100% in those over 80. As life expectancy increases worldwide, the number of cataract patients will continue to rise. The most effective treatment for cataracts is surgery. Through surgical treatment, most patients can successfully restore their vision.
2. What is the structure and function of the lens? The normal lens is an elastic, avascular, transparent body resembling a flattened biconvex lens, located behind the iris and pupil and in front of the vitreous body. It is connected to the ciliary body via lens zonules to fix its position. The tissue structure of the lens is like a peach, divided into three parts: (1) The outer surface of the lens is covered by a transparent and elastic film, which we call the lens capsule layer (similar to the skin of a peach). (2) The central part is the lens nucleus layer (similar to the pit of a peach), located in the center of the lens. With age, the nucleus layer gradually enlarges, hardens, and becomes less transparent. (3) The tissue between the lens capsule layer and the nucleus layer is called the lens cortex (similar to the meat of a peach). The lens is one of the important refractive media of the eye, with the main function of adjusting the eye to see objects at various distances, relying on the elasticity of the lens, the contraction and relaxation of the ciliary body, and the relaxation and tension of the lens zonules, which we call the accommodative function. With age, the elasticity of the lens capsule decreases, the lens nucleus enlarges and hardens, and the ciliary muscle weakens, leading to reduced accommodative ability and presbyopia.
3. What are the causes of cataracts? The causes of cataracts are multifaceted. Except for traumatic cataracts, radioactive cataracts, congenital cataracts, and diabetic cataracts, which have relatively clear causes, the formation of cataracts may involve multiple factors, making the situation quite complex. The pathogenesis of common senile cataracts has not yet been fully revealed and may be related to aging, prolonged excessive exposure to ultraviolet light, genetic factors, and malnutrition. Surveys in China have confirmed that the incidence of cataracts is relatively higher in high-altitude areas and regions with abundant sunlight radiation. This is because prolonged exposure to sunlight under ultraviolet radiation can affect the oxidative-reductive process of the lens, causing lens protein to denature and form cataracts. Additionally, common clinical conditions such as diabetes, galactosemia, and hypothyroidism can also cause cataracts.
4. Are there any risks if severe cataracts are not surgically treated? Surgery is undoubtedly the best method for treating cataracts, but it is not necessary to undergo surgery immediately after developing cataracts. As mentioned earlier, the best time for cataract surgery has already been discussed. However, some people still believe that it is okay not to have surgery if the cataract is "ripe"—after all, it's just that vision is impaired. What they don't realize is that this view is extremely wrong and dangerous. If left untreated during the progression of cataracts, many serious complications may arise, such as glaucoma and uveitis. These eye diseases often occur in the middle and late stages of cataracts, such as the dilated and hypermature stages, not only causing blindness but sometimes severe intraocular inflammation, leading to. Some patients may experience chronic eye pain that they cannot tolerate, and as a last resort, they may have to undergo. Therefore, it is important to emphasize that when cataracts reach a certain stage, surgical treatment must be performed.
5. What are the common surgical methods for cataracts? According to whether the lens capsule is intact during lens extraction, cataract surgery is divided into intraocular and extracapsular extraction. Intraocular cataract extraction and traditional extracapsular cataract extraction have become outdated. For many years, extracapsular extraction has been performed using a surgical microscope for precise operations. With the popularity and improvement of microsurgery, modern extracapsular cataract extraction combined with intraocular lens implantation has become the most widely used surgical method. The surgical procedure is relatively easier, safer, has fewer complications, and results in better postoperative vision recovery. In recent years, small-incision cataract phacoemulsification has also been developed. Postoperative wounds do not require suture closure, heal quickly, result in less postoperative astigmatism, and vision recovers rapidly.
6. Is extracapsular cataract extraction better than phacoemulsification? Phacoemulsification is an evolution of modern extracapsular cataract surgery. The surgery uses a phacoemulsification machine to crush and aspirate the lens nucleus and cortex through a corneal or scleral incision of about 3 millimeters, while preserving the posterior lens capsule to allow for the implantation of a posterior chamber intraocular lens. Its significant advantages include a small incision (only 2.8–5.5 millimeters), rapid postoperative wound healing, minimal corneal astigmatism, satisfactory vision recovery early on, and the ability to perform outpatient surgery without hospitalization. Disadvantages include higher cost, dependence on the machine, complex surgery, higher difficulty, and the potential for permanent damage if complications occur. Modern microscopic extracapsular cataract surgery is a mature and effective cataract surgical method. It requires a larger surgical incision, postoperative corneal astigmatism is greater, and higher vision is achieved after 2 weeks. However, this surgical method has been mastered by a considerable number of ophthalmologists, with lower costs, no special equipment required, good postoperative visual rehabilitation results, and a lower incidence of complications. Therefore, whether phacoemulsification or modern extracapsular cataract extraction, as long as the indications are properly understood and the surgical techniques are mastered, both are ideal cataract rehabilitation surgical methods. We believe that in poorer rural areas of China, extracapsular cataract extraction should still be promoted, and after surgery, patients should be fitted with convex lenses (hyperopes) of a larger degree, which is the most economical approach.
7. Can cataracts cause sudden vision loss? Generally, the symptoms of cataracts are a gradual decline in vision, eventually leading to blindness, without any symptoms of eye pain during the process. If a patient suddenly experiences significant vision loss without pain, it should be considered possible that there is a problem in the retina, such as retinal bleeding, papilledema, or retinal detachment, and they must see an ophthalmologist immediately without mistaking it for cataracts. During the development of senile cortical cataracts, there is a period called the dilated stage, during which the lens accumulates a lot of water, causing it to swell rapidly, increase in volume, and shallow the anterior chamber. At this stage, patients may notice a faster decline in vision, and in some cases, lens swelling and shallow anterior chamber can cause high intraocular pressure, leading to glaucoma. Patients may experience redness and pain in the eye, accompanied by headache, nausea, and vomiting. If this glaucoma is not treated in time, it can cause permanent blindness, and even subsequent cataract surgery cannot save the vision.
8. Are there age restrictions for cataract surgery? With China entering an aging society and living standards improving, more and more elderly people need cataract surgery. There is no uniform medical limit on the maximum age for cataract surgery. Some patients' families believe that the risk is too high for surgery in those over 90. In fact, this is not the case. Some elderly people in good health with stable blood pressure and heart conditions can tolerate cataract surgery, as most current cataract surgeries use topical anesthesia, causing minimal discomfort. Currently, the highest age for cataract surgery at Beijing Tongren Hospital's ophthalmology department is 103 years old. Therefore, whether or not a patient can undergo cataract surgery depends not on age but on their physical condition.
9. What tests are required before cataract surgery? Cataract surgery is a highly advanced ophthalmic procedure, and thorough preoperative examinations are necessary to ensure surgical success. Preoperative examinations for cataracts are divided into two parts: eye examinations and general physical examinations. Eye examinations generally include vision, visual function, intraocular pressure, and lacrimal passage, corneal curvature, A-scan, and B-scan. The corneal curvature and A-scan examinations are performed to calculate the degree of the intraocular lens to be implanted. General physical examinations include blood and urine tests, liver and kidney function tests, hepatitis B surface antigen, blood glucose, and other laboratory tests, as well as blood pressure and electrocardiogram. The purpose of these examinations is to understand the patient's overall condition, whether they have hypertension, diabetes, and the severity of their condition, heart function, and whether they can tolerate cataract surgery. If necessary, neurology examinations may be performed to assess the condition of cerebral blood vessels.
10. Can heart patients undergo cataract surgery? Elderly patients with cataracts are often in poor health, with varying degrees of decline in their internal organ functions, and heart problems are common in clinical practice. Whether elderly patients with heart disease can undergo cataract surgery depends on the severity of the heart disease and the condition of their heart function. Cataract surgery is a common microscopic ophthalmic procedure performed under local anesthesia, with a relatively short operation time and minimal impact on overall organ function. Generally, patients with heart disease can tolerate cataract surgery, but the following points should be noted during the operation: (1) A thorough and detailed general physical examination should be conducted before surgery to fully estimate the potential risks during the procedure, prepare emergency medications and equipment, and formulate emergency measures. If necessary, a cardiologist should be involved to monitor the patient's heart function to ensure the surgery is completed safely and successfully. (2) Psychological preparation should be done before surgery to help the patient relax. A sedative such as diazepam or phenobarbital should be given the night before surgery and on the day of surgery. (3) During cataract surgery, sufficient anesthesia should be used to minimize pain. When compressing the eye to lower intraocular pressure or fixing the eye during muscle traction, the movements should be gentle to avoid the heart-eye reflex, which can slow down or stop the heart rate. The surgical method should be chosen to be both simple and effective, and the operation time should be as short as possible. (4) After surgery, patients should not lie flat for a long time and should adopt a semi-recumbent position, engage in appropriate activities, eat more fruits and vegetables, and maintain regular bowel movements.
11. What preparations should patients make before cataract surgery? Preoperative preparation for cataract surgery is very important. In addition to cooperating with the doctor to complete a series of eye and general examinations, patients should also prepare for physical and mental adjustments. Cataract surgery is a visual rehabilitation procedure, and most of the results are excellent. However, due to individual differences between people, there is a possibility of complications, so family members should fully understand the potential complications during and after surgery and cooperate with the doctor's treatment. Before surgery, patients should also pay attention to rest, adjust their diet, quit smoking, and avoid alcohol. Patients with systemic diseases should follow the guidance of their internist to adjust blood pressure, blood glucose, and cardiovascular indicators to their optimal levels. Routine topical antibiotic eye drops should be used before surgery. Except for children undergoing general anesthesia, cataract surgery patients can eat normally before surgery but should not overeat.
12. What is an intraocular lens? From the term "intraocular lens," everyone can understand that it is a special lens made of artificial synthetic materials, called an intraocular lens. Its composition includes silicone, polymethyl methacrylate, hydrogel, etc. The shape and function of the intraocular lens are similar to those of the lens in the human eye. It is lightweight, has high optical performance, and has no antigenicity, inflammation, carcinogenicity, or biodegradability. After cataract surgery, the cloudy lens is removed, and an intraocular lens is implanted into the eye to replace the original lens, allowing external objects to focus on the retina and thus enabling the patient to see surrounding objects clearly.
13. Which intraocular lens is "best"? Before surgery, cataract patients often want to choose the "best" intraocular lens, even believing that the most expensive one is the best. However, this concern is entirely unnecessary. As we know, the implantation of an intraocular lens into the eye is to replace the function of the original lens, focusing images in the original position to allow the eye to see objects clearly. Therefore, whether it is a domestically produced or imported intraocular lens, as long as the material used to make the lens is non-toxic, the craftsmanship is fine, and the sterilization is strict, the effect after implantation is the same. Moreover, the raw materials, manufacturing equipment, and craftsmanship of domestic intraocular lenses are largely consistent with those of foreign manufacturers, while the price is much cheaper than imported intraocular lenses. Therefore, under the premise of ensuring quality, the effect of domestic intraocular lenses is the same as that of imported intraocular lenses in cataract surgery rehabilitation, and the most expensive is not necessarily the best.
14. What are the characteristics of intraocular lens implantation for cataract treatment? The intraocular lens in a person's eye is like a +9D to +12D convex lens. If the patient has no refractive errors before surgery (i.e., no myopia or hyperopia), after cataract surgery, the eye will be in a highly hyperopic state, and a convex lens of the same degree will be needed to correct vision. This "high hyperopic lens" is not aesthetically pleasing, inconvenient to wear, has poor visual quality, and makes the patient feel uncomfortable. However, an intraocular lens can achieve: (1) Replace the function of a normal human lens in anatomical position. (2) After cataract surgery in one eye, the intraocular lens implanted in the eye solves the problem of the other eye having better vision, which could not wear corrective lenses after surgery, so vision still does not improve significantly. It can also reduce discomfort caused by binocular vision differences, such as dizziness, nausea, or sometimes double vision. (3) The intraocular lens does not have the disadvantages of vision distortion, annular scotomas, or reduced visual field caused by an aphakic eye.
15. What is posterior capsule opacification? After extracapsular cataract extraction or lens trauma, the lens cortex is not completely absorbed, and the remaining part becomes cloudy, mixed with the residual lens capsule to form an opaque fibrotic membrane, or due to the proliferation of epithelial cells, transparent pearl-like bodies are formed, severely affecting vision, which is called posterior capsule opacification, or posterior capsule opacification for short.
16. What is laser treatment for posterior capsule opacification? The laser treatment for cataracts usually refers to posterior capsule opacification incision using a YAG laser. After extracapsular cataract extraction or traumatic cataracts, the remaining lens cortex, the regeneration of epithelial cells under the posterior capsule of the lens, plus surgical and inflammatory responses, form an opaque membrane with the posterior capsule, severely affecting vision. In this situation, using the high energy of YAG laser to open the center of the posterior capsule in the pupillary area, which is the visual axis of the human eye, revealing a transparent area, the patient's vision will immediately improve. If the fibrotic membrane is very hard, the YAG laser cannot cut it, and surgical removal of the posterior capsule opacification is the only option. The advantages of YAG laser treatment for posterior capsule opacification are: safe and reliable, easy to operate, no pain for the patient, and vision recovery can be "instantaneous."
17. How do congenital cataracts occur? Congenital cataracts are a common eye disease in infants and children. Cloudiness in the lens that occurs within the first year of life is called congenital cataracts; they are divided into two groups: the first group is congenital cataracts present at birth, and the second group is infantile cataracts that develop within weeks or months after birth. The reasons for the developmental disorder of the lens are basically two: ① Endogenous factors: Refers to chromosomal gene mutations that cause abnormalities in lens embryonic development, with hereditary and family history. ② Exogenous factors: Are the main cause of congenital cataracts. For example, infections during the first two months of pregnancy or contracting infectious diseases such as rubella, chickenpox, measles, or mumps during the first six months of pregnancy can damage the lens of the fetus. Hypothyroidism, malnutrition, and vitamin deficiencies can also cause congenital cataracts. Some patients may also have congenital deformities such as iris defects, microphthalmia, or underdeveloped brains in addition to cataracts.
18. When is the best time to surgically treat congenital cataracts? Congenital cataracts have different clinical manifestations, and the degree of vision loss is related to the location and extent of lens opacity. Currently, surgical treatment is still the main approach for congenital cataracts, and grasping the appropriate surgical timing is crucial in determining whether the child can restore vision. The following principles should be followed: (1) For bilateral complete congenital cataracts, since the retina does not receive normal stimulation, it severely affects visual function development, surgery should be performed as early as possible. Generally, surgery should be performed within 1–2 months after birth, with the latest not exceeding 6 months. The other eye should be operated on within 1 week after the first eye surgery, and postoperative monocular occlusion should not exceed 1 week to prevent postoperative monocular occlusion from causing form-deprivation amblyopia. (2) Bilateral incomplete cataracts: If vision in both eyes is below 0.1 and the fundus cannot be seen, surgery should also be sought as early as possible. (3) For unilateral congenital cataracts with lens opacity in the pupillary area or vision below 0.3 in both eyes, surgical treatment should be performed as early as possible at the age of 2–3. (4) For localized lens opacity that does not affect play and has vision above 0.3, surgery can be postponed to 4–5 years old, but it cannot be later than 6 years old, otherwise irreversible amblyopia may occur. (5) Patients with rubella syndrome should not undergo surgery too early, as the rubella virus still exists in the lens in the early stages of infection, and surgery may cause the virus to be released, leading to uveitis. It is generally recommended to perform surgery at the age of 2–4. In short, it must be emphasized that early surgery is important, and corrective glasses should be worn as soon as possible after surgery to prevent amblyopia. Later, an intraocular lens can be implanted in a second stage according to the development of the eye and vision.
19. Can intraocular lenses be implanted in congenital cataracts? Theoretically and technically, intraocular lens surgery should have no age restrictions, and it can be performed at any age. However, caution should be exercised when implanting intraocular lenses in children with congenital cataracts or juvenile intraocular lens implantation. In children and infants, the purpose of implanting an intraocular lens is not only to improve vision but also to prevent amblyopia and develop fusion ability. However, due to the characteristics of eye tissues in children and infants, postoperative and postoperative complications are significantly more common than in adults. Therefore, it cannot be a routine surgery. Generally, the age limit for implantation is after 2 years old, and careful consideration must be given when implanting intraocular lenses, with strict case selection and skilled surgical techniques. Postoperative close observation and strengthening of amblyopia training cannot be ignored.
20. Can vision improve after surgery for congenital cataracts? The first six months after birth are a critical period for visual development. Fixation reflex forms at 2–3 months after birth, stereoscopic vision and color vision develop at 3–4 months after birth, and vision rapidly improves at 6 months after birth. If cataracts occur during this stage, not only will vision be damaged, but the development of binocular vision and color vision will also be disrupted. To restore vision and achieve complete visual function, unilateral cataracts with obvious visual axis obstruction should be surgically treated within 2 months after birth, otherwise, form-deprivation amblyopia may occur. If bilateral cataracts significantly affect vision, surgery should also be performed as early as possible. Moreover, to shorten the time when one eye is suppressed by cataracts, the interval between surgeries for both eyes should be as short as possible. Generally, if the first eye shows no significant surgical reaction within 1 week after surgery, the second eye cataract surgery can be performed. If the cataracts are not severe or limited lens opacity, and the child still has some vision to live normally, the timing of surgery should be carefully considered, and surgery should not be rushed. However, measures to promote visual development must be taken (such as amblyopia training), and surgery should be performed after the child is slightly older. In short, even if pediatric cataracts are successfully treated surgically, the recovery of vision after surgery is often unsatisfactory compared to senile cataracts. Therefore, the prognosis for vision recovery in children with cataracts depends largely on the choice of surgical timing, surgical method, refractive correction of the aphakic eye after surgery, and postoperative amblyopia treatment.
21. Can intraocular lenses be implanted after traumatic cataracts? The use of intraocular lenses also has certain limitations, and not all cataract surgeries can have intraocular lenses implanted, especially for traumatic cataracts. This is because if intraocular lenses are forcibly implanted, severe complications may occur after surgery. Therefore, whether intraocular lenses should be implanted after traumatic cataracts should follow the following principles: (1) After traumatic cataracts are removed, if the posterior capsule is intact, intraocular lenses can be implanted in one stage. (2) Acute trauma-induced cataracts with intraocular tissue damage should be considered for two-stage implantation of intraocular lenses after debridement and suture of the wound, once the local condition is completely stable and the eye can withstand the trauma of a second surgery. (3) After traumatic cataracts, if the posterior capsule is ruptured and incomplete, the iris is defective or the anterior segment structure is disorganized, but vision function is still good, anterior chamber or suspension-type intraocular lenses can be implanted. (4) For traumatic cataracts in children after surgery, intraocular lens implantation should be carefully selected. For older patients with good local conditions, intraocular lens implantation can be attempted. (5) If traumatic cataracts are combined with corneal central leukoma, extensive iris adhesion, or，，， severely affecting vision function, intraocular lens implantation is not suitable.