Small Incision Cataract Surgery - Procedure, Benefits, and Drawbacks

Introduction

Cataract is the most prevalent cause of treatable blindness globally. It is responsible for about 75 percent of blindness in underdeveloped countries. Every year, roughly one to two million cataract cases are added to the global burden, and approximately 10 to 12 million cataract procedures are done globally.

Numerous initiatives are ongoing to solve this worldwide challenge by performing cost-effective manual tiny incision cataract surgery on the poor and needy. This has aided in making cataract services more accessible to everybody. The move from intracapsular to extracapsular cataract extraction, as well as manual small incision cataract surgery, has altered the outcomes of cataract surgery in terms of visual outcomes, quality of life, and surgical acceptability by patients.

What Is a Small Incision Cataract Surgery?

MSICS (manual small-incision cataract surgery; alternatively, SICS or SECCE) is a low-cost, small-incision variant of extracapsular cataract extraction (ECCE) primarily used in underdeveloped countries. MSICS has the benefit of a self-sealing suture less wound over regular ECCE. MSICS provides numerous unique benefits over phacoemulsification in resource-limited environments, including quicker operative time, less reliance on technology, and reduced cost.

Recent research has found that individuals having phacoemulsification and MSICS with posterior chamber intraocular lens insertion have equal results and complication rates. Cataract surgery has experienced a considerable revolution and technological breakthroughs, and MSICS is now the surgery of choice in the developing world. At the same time, phacoemulsification is the surgery of choice in the developed world.

MSICS has the advantages of being a high-quality operation, providing patient comfort, less surgical-induced astigmatism than extracapsular cataract extraction, no suture-related complications, early rehabilitation, and fewer post-operative visits. MSICS offers a low learning curve, is cost-effective, and is straightforward to use in almost all forms of cataracts.

How Is Small Incision Cataract Surgery Performed?

• Preparation can begin three to seven days before surgery using analgesics and antibacterial eye drops.

• If the artificial lens (IOL) is to be put behind the iris, the pupil is dilated with drops to see the cataract better and allow for easier access.

• Anesthesia can be administered topically in the form of eye drops or injected adjacent to (peribulbar) or behind (retrobulbar) the eye or sub-tenons.

• To assist surgery, local anesthetic nerve blocking has been proposed. The procedure may be performed on a stretcher or a reclining examination chair.

• A disinfectant, such as 10 percent povidone-iodine, is swabbed over the eyelids and surrounding skin, and topical povidone-iodine is applied to the eye.

• A cloth or sheet covering the face with an opening for the operative eye is used.

• The eyelid is maintained open with a speculum to reduce blinking during surgery.

• The incision formed for access to the cataract is smaller than for extracapsular cataract extraction and more significant than for phacoemulsification.

• Still, the wound is self-sealing due to its geometry, as with phaco. A tiny incision is made into the anterior chamber of the eye, either superior or temporal, at or near the corneal limbus, where the cornea and sclera meet.

• Ophthalmic viscosurgical devices (OVDs) or an anterior chamber maintainer, an auxiliary cannula that provides a sufficient flow of BSS to preserve the stability of the chamber's form and internal pressure, can be used during surgery.

• The cataract is removed from the anterior chamber and capsule. Separating the nucleus into two or three narrower sections is known as prosection. This prevents expanding the tunnel and, as a result, decreases medically caused astigmatism and potential endothelial damage. Following cataract removal, an intraocular lens (IOL) is often implanted into the posterior capsule.

• When the posterior capsule is injured, the IOL is put into the ciliary sulcus, or a bonded intraocular lens procedure is used.

• Following the insertion of the IOL, the ophthalmic viscosurgical devices are aspirated or flushed out and replaced with a balanced salt solution.

• Ophthalmic viscosurgical device (OVD) residues can elevate intraocular pressure (IOP) by obstructing the trabecular meshwork until they dissolve.

• The surgeon ensures that the incision does not leak fluid since wound leaking raises the danger of bacteria entering the eye and causing endophthalmitis.

• An antibiotic and steroid combination eye drop is given, and an eye shield occasionally augmented with an eye patch, is placed.

• A well-built scleral tunnel should be self-sealing, but if it does not, one or more sutures will be inserted.

• A switch to ECCE is recommended when the nucleus is too big for the SICS incision or when the nucleus is observed to be distorted during MSICS on a nanophthalmic (extremely tiny) eye.

What Are the Benefits of Cataract Surgery With a Small Incision?

1. The benefits of a smaller incision include fewer or no stitches and a shorter healing period.

2. The "small" incision is smaller than the previous ECCE incision but much larger than the phaco incision.

3. The correct geometry of the incision is critical because it influences wound self-sealing and the degree of astigmatism generated by corneal deformation during healing.

4. A sclerocorneal or scleral tunnel incision is routinely employed, which, if properly created, decreases induced astigmatism.

5. A sclerocorneal tunnel is a three-phase incision that begins with a shallow incision perpendicular to the sclera, is followed by an incision through the sclera and cornea roughly parallel to the outer surface, and is finally finished with a beveled incision into the anterior chamber.

6. Because internal pressure forces the faces of the incision together, this structure allows self-sealing.

7. The incision allows access to the inside of the anterior chamber for access to the lens and a pathway for lens removal and IOL installation. The fundamental feature of scleral tunnel incisions is self-sealing, caused by the placement of the incision relative to the limbus and the form of the wound, impacting post-operative astigmatism.

What Are the Complications of Small Incision Cataract Surgery?

1. Posterior capsule rupture can result in the retention of lens fragments, corneal edema, and cystoid macular edema; it is also linked to an increased risk of endophthalmitis and retinal detachment.

2. The incidence of intraoperative floppy iris syndrome is between 0.5 percent and two percent.

3. Complications following cataract surgery are infrequent. Although posterior vitreous detachment (PVD) can occur, it does not directly threaten vision.

4. Patients who have had cataract surgery are more likely to develop rhegmatogenous retinal detachment (RRD), the most frequent kind of retinal detachment.

5. Glaucoma can develop and be challenging to treat. It is frequently accompanied by inflammation, particularly when tiny pieces or chunks of the nucleus enter the vitreous cavity.

6. Endophthalmitis is a severe intraocular tissue infection generally due to intraocular surgical complications or penetrating trauma. Because of the use of prophylactic antibiotics, it is uncommon in cataract surgery. Around eighty percent of the time, hypopyon occurs.

7. Other potential risks include increased intraocular pressure, corneal swelling or edema, displacement or dislocation of the IOL implant (rare), and unanticipated high refractive error, either myopic or hypermetropic, due to ultrasonic mistakes.

Conclusion

SICS has transformed cataract surgery in the modern period, particularly in low-income and developing nations. SICS benefits under challenging circumstances when a great result may be attained without complications. SICS has acted as a stepping stone to executing effective phacoemulsification since the bulk of the stages in both operations are identical, except trenching and emulsification in phacoemulsification. SICS is a skill-based surgery that increases surgeons' tissue-handling abilities. The ocular surgeon, mid-level ophthalmic employees, optometrists, operating theatre workers, and nurses aiding and counseling all play essential roles in achieving a satisfactory outcome in cataract surgery after SICS. An ideal effect after SICS is the consequence of practical cooperation.