Cataract surgery: methods, types and complications after treatment

Medically reviewed: 8, December 2023

Read Time:9 Minute

Surgical treatment of cataract

Cataract, a prevalent ocular ailment, occurs when the lens of the eye becomes hazy, subsequently diminishing visual acuity. This widespread eye condition not only affects countless individuals globally but also stands as the primary cause of blindness. It particularly plagues the older population, rendering them vulnerable to impaired vision. To address this condition, cataract surgery emerges as the sole definitive treatment option.

This surgical procedure entails the extraction of the clouded lens and the subsequent implantation of an artificial intraocular lens (IOL) to restore vision and enhance overall eye health.

Cataract surgery is a widely performed and highly effective surgical procedure in the medical field, known for its significant success in improving vision and satisfying patients. Despite its numerous benefits, it is crucial to acknowledge that cataract surgery is not completely devoid of risks and complications. Therefore, a thorough evaluation before the surgery, detailed planning during the surgical process, and diligent postoperative care are essential.

The purpose of this article is to offer a comprehensive examination of the surgical treatment for cataracts, encompassing the reasons for its implementation, the various techniques employed, the outcomes achieved, and the potential complications that may arise during the procedure.

Indications for cataract surgery The main indication for cataract surgery is the presence of a lens opacity that reduces the quality of vision and interferes with the patient’s daily activities and quality of life. The decision to undergo cataract surgery should be based on the patient’s symptoms, visual acuity, visual function, and expectations, rather than on the degree of lens opacity alone.

Some factors that may influence the decision to have cataract surgery include:

  • The patient’s occupation, hobbies, and lifestyle
  • The patient’s visual needs and goals, such as driving, reading, or watching television
  • The patient’s ocular health and coexisting eye conditions, such as glaucoma, macular degeneration, or diabetic retinopathy
  • The patient’s general health and systemic conditions, such as diabetes, hypertension, or cardiovascular disease
  • The patient’s preferences and willingness to undergo surgery

The availability and accessibility of cataract surgery services

There is no specific threshold of visual acuity or lens opacity that determines the need for cataract surgery. However, some guidelines suggest that cataract surgery should be considered when the best-corrected visual acuity (BCVA) is worse than 20/40, or when the patient reports significant visual impairment or dissatisfaction with their vision. Additionally, cataract surgery may be indicated for other reasons, such as:

  • In order to enhance the identification and management of various eye conditions, like diabetic retinopathy or macular degeneration, by facilitating improved observation of the retina
  • To reduce the risk or progression of glaucoma, by lowering the intraocular pressure or facilitating the use of glaucoma medications or devices
  • To correct refractive errors, such as myopia, hyperopia, astigmatism, or presbyopia, by implanting an IOL with a specific power or design
  • To treat complications of cataract, such as phacolytic glaucoma, phacomorphic glaucoma, or lens-induced uveitis

Techniques of cataract surgery

The standard technique for cataract surgery is phacoemulsification, which involves the use of ultrasound energy to break up and aspirate the lens through a small incision in the cornea. Phacoemulsification has several advantages over the traditional extracapsular cataract extraction (ECCE), which involves the removal of the lens in one piece through a larger incision.

Phacoemulsification allows for faster wound healing, less astigmatism, less inflammation, and quicker visual recovery. Phacoemulsification can be performed under topical, local, or general anesthesia, depending on the patient’s preference, cooperation, and medical condition.

The main steps of phacoemulsification are:

Corneal incision

A small (2 to 3 mm) self-sealing incision is made in the cornea, usually at the temporal or clear corneal location, to allow the insertion of the phacoemulsification probe and the IOL injector. A second smaller incision may be made at a different location to allow the insertion of other instruments, such as a second instrument or a bimanual irrigation/aspiration device.


A circular opening is created in the anterior capsule of the lens, using a cystotome or a capsulorhexis forceps, to allow access to the lens nucleus and cortex. The size and shape of the capsulorhexis should be appropriate for the type and size of the IOL to be implanted, and should be slightly smaller than the IOL optic diameter to ensure adequate overlap and stability of the IOL within the capsular bag.

Hydrodissection and hydrodelineation

Fluid is injected under the anterior capsule to separate the lens cortex from the capsule (hydrodissection) and to separate the lens nucleus from the cortex (hydrodelineation). This facilitates the mobilization and rotation of the lens nucleus and the removal of the lens cortex.


The lens nucleus is fragmented and emulsified using the phacoemulsification probe, which delivers ultrasonic vibrations and irrigation and aspiration functions. Various techniques and modes of phacoemulsification can be used, depending on the hardness and size of the nucleus, the surgeon’s preference, and the phacoemulsification machine settings.

Some of the common techniques include divide and conquer, stop and chop, phaco chop, and phaco flip. The goal is to remove the nucleus efficiently and safely, while minimizing the amount of ultrasound energy and fluid used, and avoiding damage to the corneal endothelium, the posterior capsule, and the iris.

Cortical aspiration

The remaining lens cortex is aspirated using an irrigation/aspiration device, which can be coaxial or bimanual. Care should be taken to remove all cortical material from the capsular bag and the anterior chamber, as residual cortex can cause inflammation, posterior capsule opacification, or IOL decentration.
IOL implantation: An IOL is implanted into the capsular bag, using an injector device that folds and inserts the IOL through the corneal incision.

The IOL should be well-centered and stable within the capsular bag, and the haptics should be oriented in the desired position. The IOL power and type should be selected based on the patient’s biometry, refractive error, and visual needs. Various types of IOLs are available, such as monofocal, multifocal, toric, or accommodative IOLs, which can correct different refractive errors and provide different ranges of vision. The choice of IOL should be discussed with the patient before surgery, and the patient should be informed of the potential benefits and risks of each IOL option.

Wound closure and hydration

The corneal incision is checked for leakage and sealed with stromal hydration or sutures, if needed. The anterior chamber is filled with balanced salt solution to achieve the desired intraocular pressure and to ensure that the IOL is in the correct position. Any viscoelastic material used during surgery should be removed from the eye to prevent postoperative intraocular pressure elevation or inflammation.

Femtosecond laser-assisted cataract surgery (FLACS)

An alternative technique for cataract surgery is femtosecond laser-assisted cataract surgery (FLACS), which involves the use of a femtosecond laser to perform some of the steps of cataract surgery, such as the corneal incision, the capsulorhexis, and the lens fragmentation. FLACS has some potential advantages over phacoemulsification, such as greater precision, accuracy, and reproducibility of the surgical steps, reduced ultrasound energy and fluid use, and improved IOL centration and stability.

However, FLACS also has some limitations and challenges, such as higher cost, longer surgical time, increased surgical complexity, and possible complications, such as anterior capsule tears, corneal edema, or intraocular pressure elevation. The evidence for the superiority of FLACS over phacoemulsification is still inconclusive, and further studies are needed to compare the safety, efficacy, and cost-effectiveness of the two techniques.

Outcomes of cataract surgery

Cataract surgery is known for its consistently positive outcomes, as it often leads to significant improvements in vision and high levels of patient contentment. In fact, an extensive analysis of 50 studies found that, on average, individuals experienced a remarkable enhancement in their visual acuity after the surgery, with a mean postoperative BCVA (best-corrected visual acuity) of 0.24 logMAR, roughly equivalent to 20/30 vision.

Moreover, an astounding 90% of eyes attained a BCVA of 0.3 logMAR or better, which translates to approximately 20/40 vision or higher. These findings highlight the consistently successful nature of cataract surgery and the high likelihood of achieving improved visual outcomes for patients undergoing this procedure.

  • The mean improvement in BCVA after cataract surgery was 0.51 logMAR (approximately 6 lines), and 85% of eyes improved by 0.3 logMAR (approximately 3 lines) or more.
  • The mean postoperative refractive error after cataract surgery was -0.18 diopters (D) for spherical equivalent and 0.67 D for astigmatism, and 75% of eyes achieved a refractive error within ±1.0 D of the target.
  • The mean postoperative contrast sensitivity after cataract surgery was 1.64 log units, and 88% of eyes achieved a contrast sensitivity of 1.5 log units or more.
  • The mean postoperative patient-reported outcomes after cataract surgery were 86.7 for visual function and 87.4 for quality of life, on a scale of 0 to 100, and 95% of patients reported being satisfied or very satisfied with their surgery.
  • The outcomes of cataract surgery may vary depending on several factors, such as:
  • The preoperative visual acuity, refractive error, and ocular health of the patient
  • The surgical technique, equipment, and experience of the surgeon
  • The type, power, and design of the IOL implanted
  • The postoperative care and compliance of the patient
  • The occurrence and management of complications during or after surgery

Complications of cataract surgery

Cataract surgery is a safe and effective procedure, but it can also involve some complications such as:

Infection of the eye

Germs that get in the eye during surgery can cause an infection, which can lead to pain, redness, sensitivity to light, and vision problems. This is a rare but serious complication that requires immediate treatment with antibiotics and sometimes surgery.

Inflammation after cataract surgery

The eye may become swollen and inflamed after surgery, which can cause discomfort and blurred vision. This is a common and usually mild complication that can be treated with anti-inflammatory eye drops.

Retinal detachment

The retina, which is the light-sensitive layer at the back of the eye, may peel off from its normal position after surgery, causing vision loss. This is an emergency that requires urgent surgery to reattach the retina. Symptoms of retinal detachment include flashes of light, floating spots, or a curtain-like shadow in the vision.

Lens fragments

Sometimes, small pieces of the lens may remain in the eye after surgery, which can cause inflammation, fluid buildup, or increased pressure in the eye. These fragments may need to be removed with another surgery or a laser procedure.

Fluid buildup in the retina

The retina may swell with fluid after surgery, which can blur the vision. This is usually a temporary complication that can be treated with eye drops or injections. It may take weeks or months to resolve completely.

Dislocated intraocular lens (IOL)

The artificial lens that replaces the natural lens may shift out of place after surgery, causing double or distorted vision. This may require another surgery to reposition or replace the IOL.

Secondary cataract after surgery

Over the course of time, the capsule that encloses the intraocular lens (IOL) has the potential to develop a cloudiness, resulting in a gradual deterioration of vision and a return of haziness. This condition is scientifically referred to as posterior capsule opacification (PCO).

Thankfully, there is a straightforward and virtually painless solution known as YAG laser capsulotomy, a specialized laser procedure that effectively restores clear vision by creating a small aperture within the capsule.

Most of these complications are rare and can be prevented or treated successfully. To reduce the risk of complications, it is important to follow the instructions of the surgeon before and after surgery, and to report any unusual symptoms or changes in vision to the doctor as soon as possible. Cataract surgery can improve the quality of life and vision for many people, and the benefits usually outweigh the risks.

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