the wound is sealed by elevating the pressure inside the globe with bss, which presses the internal tissue against the external tissue of the incision, holding the incision closed. if this does not achieve a satisfactory seal, a suture may be added. the wound is then hydrated. manual small incision cataract surgery (msics) many of the steps are similar and some may be the same as for phacoemulsification; the main differences are related to the alternative method of incision and cataract extraction from the capsule and eye. preparation may begin three-to-seven days before surgery with the preoperative application of nsaids and antibiotic eye drops. the pupil is dilated using drops if the iol is to be placed behind the iris to help better visualise the cataract. pupil-constricting drops are reserved for secondary implantation of the iol in front of the iris, when the cataract has already been removed without primary iol implantation. anaesthesia may be placed topically as eyedrops or injected next to (peribulbar) or behind (retrobulbar) the eye or sub-tenons. local anaesthetic nerve blocking has been recommended to facilitate surgery. topical anaesthetics may be used at the same time as a intracameral lidocaine injection to reduce pain during the operation. oral or intravenous sedation may also be used to reduce anxiety. general anaesthesia is rarely necessary but may be used for children and adults with medical or psychiatric issues affecting their ability to remain still during the procedure. the operation may occur on a stretcher or a reclining examination chair. the eyelids and surrounding skin are swabbed with a disinfectant, such as 10% povidone-iodine, and topical povidone-iodine is put in the eye. the face is covered with a cloth or sheet with an opening for the operative eye. the eyelid is held open with a speculum to minimize blinking during surgery. pain is usually minimal in properly anaesthetised eyes, though a pressure sensation and discomfort from the bright operating microscope light is common. bridle sutures may be used to help to stabilize the eyeball during sclerocorneal tunnel incision, and during extraction of the nucleus and epinucleus through the tunnel. the small incision into the anterior chamber of the eye is made at or near the corneal limbus, where the cornea and sclera meet, either superior or temporal. advantages of the smaller incision include use of few-or-no stitches and shortened recovery time. the "small" incision is small in comparison with the earlier ecce incision but considerably larger than the phaco incision. the precise geometry of the incision is important as it affects the self-sealing of the wound and can cause astigmatism by distortion of the cornea during healing. a sclerocorneal or scleral tunnel incision is commonly used, which reduces induced astigmatism if suitably formed. a sclerocorneal tunnel, a three-phase incision, starts with a shallow incision perpendicular to the sclera, followed by an incision through the sclera and cornea approximately parallel to the outer surface, and then a beveled incision into the anterior chamber. this structure provides the self-sealing characteristic because internal pressure presses together the faces of the incision. the depth of the anterior chamber and position of the posterior capsule may be maintained during surgery by ovds or an anterior chamber maintainer, which is an auxiliary cannula providing a sufficient flow of bss to maintain the stability of the shape of the chamber and internal pressure. using an instrument called a cystotome, capsulotomy, also known as a cystotomy, is made to open the surface of the lens capsule . the continuous curvilinear capsulorhexis technique is in common use. an anterior capsulotomy is the opening of the front portion of the lens capsule, providing access to remove the cataract, whereas a posterior capsulotomy is an opening of the back portion of the lens capsule, which is not usually necessary or desirable unless it has opacified. the types of capsular openings commonly used in msics are the continuous curvilinear capsulorhexis, the can-opener capsulotomy, and the envelope capsulotomy. the cataract lens is then removed from the capsule and anterior chamber using hydroexpression viscoexpression, or more-direct mechanical methods. following cataract removal, an iol is usually inserted into the posterior capsule. when the posterior capsule is damaged, the iol may be inserted into the ciliary sulcus, or a glued intraocular lens technique may be applied. after the iol is inserted, the ophthalmic viscosurgery device is aspirated and replaced with bss, and the wound is closed. the surgeon checks the incision does not leak fluid because wound leakage increases the risk of microorganisms gaining access into the eye and predisposing it to endophthalmitis. an antibiotic/steroid combination eye drop is put in, and an eye shield may be applied, sometimes supplemented with an eye patch. converting to eccs to manage a contingency sometimes a change from a phacoemulsification procedure to ecce may be necessary.this may occur in the event of posterior capsule rupture, zonular dehiscence, or a dropped nucleus with a nuclear fragment more than half the size of the cataract; problematic capsulorhexis with a hard cataract; or a very dense cataract where phacoemulsification is likely to cause permanent damage to the cornea. similarly, a change from msics to ecce is appropriate whenthe nucleus is too large for the msics incision; and in cases where the nucleus is found to be deformed during msics on a nanophthalmic (very small) eye. complications complications can develop during and after surgery. during surgery posterior capsular rupture, a tear in the posterior capsule of the natural lens, is the most-common complication during cataract surgery, with a rate of around 0.5% to 5.2%. surgical management may involve anterior vitrectomy and occasionally, alternative planning for implanting the iol, either in the ciliary sulcus—the space between the iris and the ciliary body—in the anterior chamber in front of the iris, or less commonly, sutured to the sclera. posterior capsule rupture can cause lens fragments to be retained, corneal oedema, and cystoid macular oedema; it is also associated with a six-times increase of risk of endophthalmitis and as much as 19 times increase in the risk of retinal detachment. management methods include the intraocular lens scaffold procedure. suprachoroidal hemorrhage is a rare complication of intraocular surgery where the ciliary arteries bleed into the space between the choroid and the sclera. it is a potentially vision-threatening pathology. risk factors for suprachoroidal hemorrhage include anterior chamber intraocular lens (aciol), axial myopia, advanced age, atherosclerosis, glaucoma, systolic hypertension, tachycardia, uveitis, and previous ocular surgery. immediate and effective management of a suprachoroidal hemorrhage is necessary to protect vision. intraoperative floppy iris syndrome has an incidence of around 0.5% to 2.0%. iris or ciliary body injury has an incidence of about 0.6%-1.2%. in the event of a posterior capsule rupture, fragments of the nucleus can find their way through the tear into the vitreous chamber; this is called posterior dislocation of nuclear fragments. recovery of the fragments is not always desirable and it is rarely successful. the rest of the fragments should generally be stabilised first, and vitreous prevented from entering the anterior chamber. removal of the fragments may be best referred to a vitreoretinal specialist. other complications include failure to aspirate all lens fragments, leaving some in the anterior chamber; and incisional burns caused by overheating of the phacoemulsification tip when ultrasonic power continues while the irrigation or aspiration lines are blocked—the flow through these lines is used to keep the tip cool. burns to the incision may make closure difficult and can cause corneal astigmatism. after surgery slit lamp photo of iol showing posterior capsular opacification (pco) visible a few months after implantation of intraocular lens in eye, seen on retroillumination complications after cataract surgery are relatively uncommon. posterior vitreous detachment (pvd) does not directly threaten vision but is of increasing interest because the interaction between the vitreous body and the retina might play a decisive role in the development of major pathological vitreoretinal conditions. pvd may be more problematic with younger patients because many patients older than 60 have already gone through pvd. pvd may be accompanied by peripheral light flashes and increasing numbers of floaters. some people develop a posterior capsular opacification (pco), also called an after-cataract. as a physiological change expected after cataract surgery, the posterior capsular cells undergo hyperplasia and cellular migration, showing up as a thickening, opacification and clouding of the posterior lens capsule, which is left behind after the cataract is removed, for placement of the iol. this may compromise visual acuity, and can be safely and painlessly corrected using a laser to make a hole in the posterior lens capsule. it usually is a quick outpatient procedure that uses a nd-yag laser to clear the central portion of the opacified posterior pole of the capsule (posterior capsulotomy). this creates a clear central visual axis to improve visual acuity. in very thick opacified posterior capsules, a manual surgical capsulectomy may be needed. a posterior capsulotomy must be taken in consideration in the event of iol replacement because vitreous can migrate toward the anterior chamber through the opening previously occluded by the iol. posterior capsule opacification has an incidence of about 0.3% to 28.4%. retinal detachment normally occurs at a prevalence of 1 in 1,000 (0.1%) but patients who have had cataract surgery are at an increased risk (0.5–0.6%) of developing rhegmatogenous retinal detachment (rrd)—the most-common form of retinal detachment. cataract surgery increases the rate of vitreous humour liquefaction, which leads to increased rates of rrd. when a retinal tear occurs, vitreous liquid enters the space between the retina and retinal pigmented epithelium (rpe), and presents as flashes of light (photopsia), dark floaters, and loss of peripheral vision. toxic anterior segment syndrome (tass), a non-infectious inflammatory condition, may occur following cataract surgery. it is usually treated with topical corticosteroids in high dosage and frequency. endophthalmitis is a serious infection of the intraocular tissues, usually following intraocular surgery complications or penetrating trauma, and one of the most-severe. it is rare in cataract surgery due to the use of prophylactic antibiotics, there is some concern the clear cornea incision might predispose to the increase of endophthalmitis but no conclusive study has corroborated this suspicion. an intracameral injection of antibiotics may be used as a preventive measure. a meta-analysis showed the incidence of endophthalmitis after phacoemulsification to be 0.092%. the risk is higher with diabetes, advanced age, larger incision procedures, and vitreous communication with the anterior chamber due to posterior capsule rupture. the risk of vitreous infection is at least six times higher than for the aqueous. typical presentation is within two weeks after the procedure with decreased visual acuity, red-eye, and pain. hypopyon occurs about 80% of the time. common infective agents include coagulase-negative staphylococci and staphylococcus aureus in about 80% of infections. management includes vitreous humour tap and injection of broad-spectrum antibiotics. outcomes can be severe even with treatment, and may range from permanently decreased visual acuity to no light perception, depending on the microbiological etiology. glaucoma may occur and may be very difficult to control. it is usually associated with inflammation, especially when small fragments or chunks of the nucleus access the vitreous cavity. some experts recommend early intervention by posterior pars plana vitrectomy when this condition occurs. in most cases, raised post-operative intraocular pressure is transient and benign, usually returning to baseline within 24 hours without intervention. glaucoma patients may experience further visual field loss or a loss of fixation, and are more likely to experience intraocular pressure spikes. secondary glaucoma is an important complication of surgery for congenital cataracts. it can occur several years after cataract surgery so these patients need lifelong surveillance. mechanical pupillary block is shallowing of the anterior chamber by obstruction of the flow of aqueous humour flow through the pupil by the vitreous face or iol; this can occur when contact between the edge of the pupil and an adjacent structure blocks the flow of aqueous through the pupil. the iris then bulges forward and closes the angle between the iris and cornea, blocking drainage through the trabecular meshwork and causing an increase in intraocular pressure. this is more frequent as a complication of anterior chamber intraocular lens implantation, but has been known to occasionally occur with posterior iol implantation. swelling of the macula, the central part of the retina, results in macular oedema and can occur a few days or weeks after surgery.