Phacoemulsification

Phacoemulsification

Phacoemulsification: Cataract surgery, by a temporal approach, using a phacoemulsification probe (in right hand) and "chopper"(in left hand), being done under operating microscope at a Navy medical center

Phacoemulsification refers to modern cataract surgery in which the eye's internal lens is emulsified with an ultrasonic handpiece, and aspirated from the eye. Aspirated fluids are replaced with irrigation of balanced salt solution, thus maintaining the anterior chamber, as well as cooling the handpiece.

Preparation and precautions

The eye is a delicate organ, requiring extreme care before, during and after a surgical procedure. An expert ophthalmologist must identify the need for phacoemulsification and be in charge of conducting the procedure safely. Many university programs allow patients to specify if they want to be operated upon by the consultant or the resident / fellow.

Proper anesthesia is a must for any eye surgery. Topical anesthesia is most commonly employed, using tetracaine eyedrops or lidocaine gel. Alternatively, lidocaine and/or longer-acting marcaine anesthestic may be injected into the area surrounding (peribulbar block) or behind (retrobulbar block) the eye muscle cone to more fully immobilize the extraocular muscles and minimize pain sensation. A facial nerve block using Lidocaine and Bupivacaine may occasionally be performed to reduce lid squeezing. General anesthesia is recommended for children, traumatic eye injuries with cataract, for very apprehensive or uncooperative patients and animals. Cardiovascular monitoring is preferable in local anesthesia and is mandatory in general anesthesia. Proper sterile precautions are taken to prepare the area for surgery, including use of antiseptics like povidone-iodine. Sterile drapes, gowns and gloves are employed. A plastic sheet with a receptacle helps collect the fluids during phacoemulsification. An eye speculum is inserted to keep the eyelids open.

Surgical technique

Before the Phacoemulsification can be performed, one or more incisions are made in the eye to allow the introduction of surgical instruments. The surgeon then removes the anterior face of the capsule that contains the lens inside the eye. Phacoemulsification surgery involves the use of a machine with microprocessor-controlled fluid dynamics. These can be based on peristaltic or venturi type of pump.

The phaco probe is an ultrasonic handpiece with a titanium or steel needle. The tip of the needle vibrates at ultrasonic frequency to sculpt and emulsify the cataract while the pump aspirates particles through the tip. In some techniques, a second fine steel instrument called a "chopper" is used from a side port to help with chopping the nucleus into smaller pieces. The cataract is usually broken into two or four pieces and each piece is emulsified and aspirated out with suction. The nucleus emulsification makes it easier to aspirate the particles. After removing all hard central lens nucleus with phacoemulsification, the softer outer lens cortex is removed with suction only.

An irrigation-aspiration probe or a bimanual system is used to aspirate out the remaining peripheral cortical matter, while leaving the posterior capsule intact. As with other extracapsular cataract extraction procedures, an intraocular lens implant (IOL), is placed into the remaining lens capsule. For implanting a PMMA IOL, the incision has to be enlarged. For implanting a foldable IOL, the incision does not have to be enlarged. The foldable IOL, made of silicone or acrylic of appropriate power is folded either using a holder/folder, or a proprietary insertion device provided along with the IOL.

It is then inserted and placed in the posterior chamber in the capsular bag (in-the-bag implantation). Sometimes, a sulcus implantation may be required because of posterior capsular tears or because of zonulodialysis. Because a smaller incision is required, few or no stitches are needed and the patient's recovery time is usually shorter when using a foldable IOL..

History

Charles Kelman introduced phacoemulsification in 1967 after being inspired by his dentist's ultrasonic probe.

Traumatic Cataract

Traumatic Cataract

Introduction
Traumatic cataracts occur secondary to blunt or penetrating ocular trauma. Infrared energy (glass-blower's cataract), electric shock, and ionizing radiation are other rare causes of traumatic cataracts.
Cataracts caused by blunt trauma classically form stellate- or rosette-shaped posterior axial opacities that may be stable or progressive, whereas penetrating trauma with disruption of the lens capsule forms cortical changes that may remain focal if small or may progress rapidly to total cortical opacification.
Lens dislocation and subluxation are commonly found in conjunction with traumatic cataract. Other associated complications include phacolytic, phacomorphic, pupillary block, and angle-recession glaucoma; phacoanaphylactic uveitis; retinal detachment; choroidal rupture; hyphema; retrobulbar hemorrhage; traumatic optic neuropathy; and globe rupture.
Traumatic cataract can present many medical and surgical challenges to the ophthalmologist. Careful examination and a management plan can simplify these difficult cases and provide the best possible outcome.

Pathophysiology
Blunt trauma is responsible for coup and contrecoup ocular injury. Coup is the mechanism of direct impact. It is responsible for Vossius ring (imprinted iris pigment) sometimes found on the anterior lens capsule following blunt injury. Contrecoup refers to distant injury caused by shockwaves traveling along the line of concussion.
When the anterior surface of the eye is struck bluntly, there is a rapid anterior-posterior shortening accompanied by equatorial expansion. This equatorial stretching can disrupt the lens capsule, zonules, or both. Combination of coup, contrecoup, and equatorial expansion is responsible for formation of traumatic cataract following blunt ocular injury.
Penetrating trauma that directly compromises the lens capsule leads to cortical opacification at the site of injury. If the rent is sufficiently large, the entire lens rapidly opacifies, but when small, cortical cataract can seal itself off and remain localized.

Frequency
United States
Approximately 2.5 million eye injuries occur annually in the United States. It is estimated that approximately 4-5% of a comprehensive ophthalmologist's patients are seen secondary to ocular injury. Traumatic cataract may present as acute, subacute, or late sequela of ocular trauma.

Mortality/Morbidity
• Trauma is the leading cause of monocular blindness in people younger than 45 years.
• Annually, approximately 50,000 people are left unable to read newsprint as a result of ocular trauma.
• Only 85% patients who experience anterior segment injury reach a final visual acuity of 20/40 or better, whereas only 40% patients with posterior segment injury reach this level.
Sex
The male-to-female ratio in cases of ocular trauma is 4:1.
Age
• Work- and sports-related eye injuries most commonly occur in children and young adults.
• Between 1985-1991, a National Eye Trauma System study reported a median age of 28 years in 648 assault-related cases.

Clinical
History
• Mechanism of injury - Sharp versus blunt
• Past ocular history - Previous eye surgery, glaucoma, retinal detachment, diabetic eye disease
• Past medical history - Diabetes, sickle cell, Marfan syndrome, homocystinuria, hyperlysinemia, sulfate oxidase deficiency
• Visual complaints
o Decreased vision - Cataract, lens subluxation, lens dislocation, ruptured globe, traumatic optic neuropathy, vitreous hemorrhage, retinal detachment
o Monocular diplopia - Lens subluxation with partial phakic and aphakic vision
o Binocular diplopia - Traumatic nerve palsy, orbital fracture
o Pain - Glaucoma secondary to hyphema, pupillary block, or lens particles; retrobulbar hemorrhage; iritis

Physical
• Complete ophthalmic examination (defer in case of globe compromise)
o Vision and pupils - Presence of afferent pupillary defect (APD) indicative of traumatic optic neuropathy
o Extraocular motility - Orbital fractures or traumatic nerve palsy
o Intraocular pressure - Secondary glaucoma, retrobulbar hemorrhage
o Anterior chamber - Hyphema, iritis, shallow chamber, iridodonesis, angle recession
o Lens - Subluxation, dislocation, capsular integrity (anterior and posterior), cataract (extent and type), swelling, phacodonesis
o Vitreous - Presence or absence of hemorrhage, posterior vitreous detachment
o Fundus - Retinal detachment, choroidal rupture, commotio retinae, preretinal hemorrhage, intraretinal hemorrhage, subretinal hemorrhage, optic nerve pallor, optic nerve avulsion
Causes
Traumatic cataracts occur secondary to blunt or penetrating ocular trauma.

Differential Diagnoses
Cataract, Senile
Laceration, Corneoscleral

Choroidal Rupture
Sudden Visual Loss
Ectopia Lentis

Glaucoma, Angle Recession

Hyphema

Other Problems to Be Considered
Globe rupture
Orbital fractures
Retinal detachment
Secondary glaucoma
Traumatic optic neuropathy

Workup
Imaging Studies
• B-scan - If the posterior pole cannot be visualized
• A-scan - Prior to cataract extraction
• CT scan of the orbits - Fractures and foreign bodies

Treatment
Medical Care
• If glaucoma is a problem, control intraocular pressure with standard medications. Add corticosteroids if lens particles are the cause or if iritis is present.
• Focal cataract
o Observation is warranted if the cataract is outside the visual axis.
o Miotic therapy may be of benefit if the cataract is close to the visual axis.
• In some cases of lens subluxation, miotics may correct monocular diplopia. Mydriatics may allow for vision around the lens with aphakic correction.

Surgical Care
• Planning the surgical approach is of the utmost importance in cases of traumatic cataract.
• Preoperative capsular integrity and zonular stability should be surmised.
• In cases of posterior dislocation without glaucoma, inflammation, or visual obstruction, surgery may be avoided.
• Indications for surgery include the following:
o Unacceptable decreased vision
o Obstructed view of posterior pathology
o Lens-induced inflammation or glaucoma
o Capsular rupture with lens swelling
o Other trauma-induced ocular pathology necessitating surgery
• Standard phacoemulsification may be performed if the lens capsule is intact and sufficient zonular support remains.
• Intracapsular cataract extraction is required in cases of anterior dislocation or extreme zonular instability. Anterior dislocation of the lens into the anterior chamber requires emergency surgery for its removal, as it can cause pupillary block glaucoma.
• Pars plana lensectomy and vitrectomy may be best in cases of posterior capsular rupture, posterior dislocation, or extreme zonular instability.
• Automated irrigation/aspiration can be used in patients younger than 35 years.
• Lens implantation
o Capsular fixation is the preferred placement if the lens capsule and zonular support are intact.
o Polymethyl methacrylate (PMMA) capsular tension rings allow capsular fixation in cases of zonular dialysis less than 180 degrees.
o Sulcus fixation is safe if the posterior capsule is compromised but zonular support is maintained.
o Suture fixation is chosen if both capsular and zonular supports are insufficient and the angle is minimally damaged.
o Anterior chamber placement is an option if no posterior support remains and iris or ciliary body trauma prevents suture fixation.
o Aphakia may be a better choice in young children and in patients with highly inflamed eyes, as they may experience better outcomes if lens implantation is deferred.
Consultations
Vitreoretinal consultation is necessary if a pars plana approach is mandated and the surgeon is untrained in posterior segment surgery.

Follow-up
Further Outpatient Care
• Patients should receive follow-up care as needed.

Deterrence/Prevention
• Protective eyewear should be worn when participating in any high-risk activities.
• Most serious eye trauma can be avoided if proper eye and face protectors are used.

Complications
• Lens dislocation and subluxation are commonly found in conjunction with traumatic cataract.
• Other associated complications include the following: phacolytic, phacomorphic, pupillary block, and angle-recession glaucoma; phacoanaphylactic uveitis; retinal detachment; choroidal rupture; hyphema; retrobulbar hemorrhage; traumatic optic neuropathy; and globe rupture.
Prognosis
• The prognosis is dependent on the extent of the injury.
Patient Education
• Protective eyewear is important in high-risk activities to avoid injury.
• For excellent patient education resources, visit eMedicine's Eye and Vision Center. Also, see eMedicine's patient education article Cataracts.
Miscellaneous
Medicolegal Pitfalls
• The nature of the injury should be accurately documented, including location, time, and circumstances of the injury, as well as whether protective eyewear was worn.



Multimedia

Media file 1: Classic rosette-shaped cataract in a 36-year-old man, 4 weeks after blunt ocular injury.

Classic rosette-shaped cataract in a 36-year-old man, 4 weeks after blunt ocular injury.
Media file 2: Same cataract as seen in Media file 1, viewed by retroillumination

Cataract Surgery

Cataract Surgery

In cataract surgery, the cloudy natural lens must be removed from the eye. After that, in most cases a permanent intraocular lens (IOL) implant replaces the natural lens to restore focusing power.
When to have cataract surgery often is a subjective decision, based on how well you are able to see during routine activities. You might be able to drive, watch television and work at a computer for quite a few years, even after you are first diagnosed with cataracts.
However, if you have cataracts, you may eventually start to notice "ghost" images and declining visual clarity, which can't be corrected with glasses or contacts. Colors may begin to look faded, too. If your functional vision is impaired significantly and it becomes difficult for you to perform your normal daily activities, it may be time for cataract surgery.

Preparing for Cataract Surgery
Once you and your eye doctor have decided that you will have your cataract removed, the eye surgeon will examine you. For the immediate time period before and after cataract surgery, ask your surgeon if you should continue your usual medications and nutritional supplements.
As an example, a common drug that treats men with enlarged prostates — Flomax and similar medications known as alpha-blockers — could cause problems associated with intraoperative floppy iris syndrome (IFIS) during cataract surgery. Patients on Flomax or similar medications should notify their eye surgeon before undergoing cataract surgery.
You may be given a choice of implantation with a regular single-vision (monofocal) intraocular lens or a presbyopia-correcting intraocular lens for replacement of your eye's natural lens.
Determining the right IOL for you can be based on many factors, including your lifestyle and ability to pay. If you are interested in correcting presbyopia, which all people have beginning at around age 40, you potentially could restore your ability to see at all distances with a multifocal IOL or accommodating IOL.
However, you must consider that extra cataract surgery costs do occur with "premium" IOLs, even though they may reduce or eliminate dependency on eyeglasses.
Before cataract surgery, your eye will be thoroughly measured in a preliminary eye exam to determine the proper power of the intraocular lens that will be placed in your eye. If you choose a premium IOL, you may need extra tests to make sure measurements are exact and that you don't have other vision problems that might hamper the performance of the IOL.
If you need cataracts removed from both eyes, surgery usually will be done on only one eye at a time. An uncomplicated surgical procedure lasts only about 10 minutes. However, you may be in the outpatient facility for 90 minutes or longer, because extra time will be needed for preparation and recovery.
At least a few days to weeks typically will be needed between surgeries, so that your first eye has the chance to heal and be evaluated in a follow-up exam for any possible problems.

What Happens During Cataract Surgery?
Cataract surgery usually is done on an outpatient basis. You may be asked to skip breakfast and avoid drinking liquids, depending on the time of your surgery. Also, do not wear eye makeup on the day of surgery. Upon arrival at the facility, you will be given eye drops to dilate your pupils and perhaps a sedative to help you relax. A local or topical anesthetic will make the operation painless.

The skin around your eye will be thoroughly cleansed, and sterile coverings will be placed around your eye and head. Under an operating microscope, at least one small incision is made into the eye. The surgeon will then remove your cloudy lens (the cataract).
This procedure can be performed using an ultrasound-driven instrument that "sonically" breaks up the cataract (phacoemulsification) as it is suctioned (aspirated) out of the eye.
In another surgical method, special instruments are used to mechanically break up the cloudy lens into small pieces (phacofracture) and remove them directly from the eye through a small incision.
The surgeon will insert a plastic or silicone IOL inside the eye to replace the natural lens that was removed.
Most incisions used for cataract surgery are self-sealing. However, on occasion, incisions may need to be sutured. When stitches are used, they rarely need to be removed.
Cataract Surgery Recovery
When the operation is over, the surgeon will usually place a protective shield over your eye. After a short stay in the outpatient recovery area, you will be ready to go home. Plan to have someone else drive you home.

A protective patch will be placed over your eye following cataract surgery.

You will need to administer eye drops, as prescribed by your surgeon, several times daily during the next few weeks. You also will need to wear your protective eye shield while sleeping or napping, for about a week after surgery. You will be given sun shades to help protect your eye in bright light.
During at least the first week of your recovery, it is essential that you avoid:
• Strenuous activity and heavy lifting (nothing over 25 pounds).
• Bending, exercising and similar activities that might stress your eye while it is healing.
• Water that might splash into your eye and cause infection. Keep your eye closed while showering or bathing. Also, avoid swimming or hot tubs for at least two weeks.
• Any activity (such as changing cat litter boxes) that would expose your healing eye to dust, grime or other infection-causing contaminants.
Although the basic postoperative instructions are similar among most eye surgeons, each surgeon may have specific recovery instructions depending on the outcome of your surgery. Always follow your surgeon's specific instructions, which you will receive prior to your discharge from the outpatient facility.
Complications of Cataract Surgery
Glaucoma or a buildup of pressure within the eye (intraocular pressure) also occurs sometimes after cataract surgery. If your eye pressure remains high, you may need additional treatment such as eye drops, a laser procedure, pills or additional surgery.

Phacoemulsification in cataract surgery involves insertion of a tiny, hollowed tip that uses high frequency (ultrasonic) vibrations to "break up" the eye's cloudy lens (cataract). The same tip is used to suction out the lens.


After the eye's natural lens is removed during cataract surgery, an artificial or intraocular lens is implanted to take its place.
Far more rarely, you might experience problems such as a decentered intraocular lens that might need to be repositioned or replaced in a second surgery.
Various complications, ranging from minor to serious, also can take place as a direct result of the surgical procedure, including tearing of the posterior capsule holding the intraocular lens in place.
Detached retinas also are possible in a small percentage of people who have undergone cataract surgery, particularly if they have unusually long eyes associated with higher degrees of nearsightedness.
Some eye surgeons dispute this direct association with cataract surgery, because highly nearsighted people already are at risk of getting a detached retina with or without cataract surgery. Cumulative rates of detached retinas occurring in highly myopic general populations who underwent cataract surgery or refractive lens exchange are roughly 1 percent in some studies, which is about the same risk if you never underwent a procedure.
However, a common complication that creates a "secondary cataract" may require a YAG laser capsulotomy procedure. A high myope who undergoes both cataract surgery and a subsequent YAG laser capsulotomy may have a significantly greater risk of developing a detached retina.
Endophthalmitis causing widespread inflammation or infection of the eye can be a serious side effect of cataract surgery that can lead to permanent vision loss and even blindness. Various studies indicate that endophthalmitis occurs in about one out of every thousand cataract surgeries. Endophthalmitis also is more likely to be seen in people with compromised immune systems associated with conditions such as diabetes.
However, even serious cataract surgery complications often can be resolved with appropriate follow-up treatments.

Cataract Surgery Outcomes
A comprehensive study reported in Archives of Ophthalmology in 1994 noted that 95.5 percent of healthy eyes achieved 20/40 uncorrected vision (legally acceptable for driving) or better outcomes following cataract surgery. Of the more than 17,000 eyes evaluated, fewer than 2 percent had sight-threatening complications.

Bruising or a black eye can result from cataract surgery, if an injection is used to numb the eye.
Remember that sight-threatening complications often are associated with individuals who are much older or who already have poor underlying health affecting how their eyes heal. Also, some people have complications because their cataracts are far more advanced or "hardened" at the time of surgery, making them difficult to remove.
A Swedish study published in the British Journal of Ophthalmology in November 1999 found that self-reported outcomes among people who had undergone cataract surgery were less satisfactory when other eye problems were present. Younger people undergoing cataract surgery reported the highest satisfaction levels.
The British journal also reported study results in December 2000 indicating that people in their 60s undergoing cataract surgery were 4.6 percent more likely to achieve 20/40 uncorrected vision or better than people in their 80s.
Laser-Based Cataract Surgery
Laser-based cataract surgery may become much more common in the near future.
In September 2009, LenSx Lasers Inc. (Aliso Viejo, Calif.) was granted FDA clearance to market femtosecond laser technology for capsulotomies, which involve making incisions into the eye. The incisions allow the eye surgeon access for removal of a cloudy lens (cataract), which then is replaced with an artificial lens.
Another femtosecond laser system currently under development ultimately could provide "all-laser" cataract surgery, according to LensAR CEO Randy Frey of Winter Park, Fla.
Frey's company is investigating use of the femtosecond laser system for all aspects of cataract surgery, including precise "laser cuts" into the eye. The system also can "break up" a cloudy lens to allow easy aspiration of the fragments from the eye.
Frey said femtosecond lasers potentially can be used to create limbal relaxing incisions (LRIs) for astigmatism correction as part of a cataract procedure.
Depending on FDA approval, LensAR femtosecond laser systems for cataract surgery could be available as early as 2010.
Optimedica Pascal System (Santa Clara, Calif.) is another femtosecond laser system currently under development for use in cataract surgery.

Cataract

Cataract

Cataract is a clouding of the eye's natural lens, which lies behind the iris and the pupil. The lens works much like a camera lens, focusing light onto the retina at the back of the eye. The lens also adjusts the eye's focus, letting us see things clearly both up close and far away.

The lens is mostly made of water and protein. The protein is arranged in a precise way that keeps the lens clear and lets light pass through it.

But as we age, some of the protein may clump together and start to cloud a small area of the lens. This is a cataract, and over time, it may grow larger and cloud more of the lens, making it harder to see.

Researchers are gaining additional insights about what causes these specific types of proteins (crystallins) to cluster in abnormal ways to cause lens cloudiness and cataracts. One recent finding suggests that fragmented versions of these proteins bind with normal proteins, disrupting normal function.

Cataracts are classified as one of three types:

• A subcapsular cataract begins at the back of the lens. People with diabetes, high farsightedness or retinitis pigmentosa or those taking high doses of steroids, may develop a subcapsular cataract.
• A nuclear cataract is most commonly seen as it forms. This cataract forms in the nucleus, the center of the lens, and is due to natural aging changes.
• A cortical cataract, which forms in the lens cortex, gradually extends its spokes from the outside of the lens to the center. Many diabetics develop cortical cataracts.

Cataract Symptoms and Signs

A cataract starts out small and at first has little effect on your vision. You may notice that your vision is blurred a little, like looking through a cloudy piece of glass or viewing an impressionist painting.

A cataract may make light from the sun or a lamp seem too bright or glaring. Or you may notice when you drive at night that the oncoming headlights cause more glare than before. Colors may not appear as bright as they once did.

The type of cataract you have will affect exactly which symptoms you experience and how soon they will occur. When a nuclear cataract first develops, it can bring about a temporary improvement in your near vision, called "second sight." Unfortunately, the improved vision is short-lived and will disappear as the cataract worsens. On the other hand, a subcapsular cataract may not produce any symptoms until it's well-developed.

What Causes Cataracts?

No one knows for sure why the eye's lens changes as we age, forming cataracts. Researchers are gradually identifying factors that may cause cataracts — and information that may help to prevent them.

Many studies suggest that exposure to ultraviolet light is associated with cataract development, so eyecare practitioners recommend wearing sunglasses and a wide-brimmed hat to reduce your exposure. Other studies suggest people with diabetes are at risk for developing a cataract.

The same goes for users of steroids, diuretics and major tranquilizers, but more studies are needed to distinguish the effect of the disease from the consequences of the drugs themselves.

Some eyecare practitioners believe that a diet high in antioxidants such as beta-carotene (vitamin A), selenium and vitamins C and E, may forestall cataract development. Meanwhile, eating a lot of salt may increase your risk.

Other risk factors include cigarette smoke, air pollution and heavy alcohol consumption.

A small study published in 2002 found lead exposure to be a risk factor; another study in December 2004, of 795 men age 60 and older, came to a similar conclusion.

But larger studies are needed to confirm whether lead can definitely put you at risk and, if so, whether the risk is from a one-time dose at a particular time in life or from chronic exposure over years.

Cataract Treatment

When symptoms begin to appear, you may be able to improve your vision for a while using new glasses, strong bifocals, magnification, appropriate lighting or other visual aids.

Think about surgery when your cataracts have progressed enough to seriously impair your vision and affect your daily life. Many people consider poor vision an inevitable fact of aging, but cataract surgery is a simple, relatively painless procedure to regain vision.

Cataract Surgery is very successful in restoring vision. In fact, it is the most frequently performed surgery in the United States, with more than 3 million Americans undergoing cataract surgery each year. Nine out of 10 people who have cataract surgery regain very good vision, somewhere between 20/20 and 20/40.

During surgery, the surgeon will remove your clouded lens and in most cases replace it with a clear, plastic intraocular lens (IOL).

New IOLs are being developed all the time to make the surgery less complicated for surgeons and the lenses more helpful to patients. Presbyopia-correcting Intra Oculer Lens potentially help you see at all distances, not just one. Another new type of IOL blocks both ultraviolet and blue light rays, which research indicates may damage the retina (see illustration).

Read more on this website about what to expect if you have Cataract Surgery and how to deal with rare Cataract Surgery Complications Also, men should be aware that certain prostate drugs can cause intraoperative floppy iris syndrome (IFIS) during a cataract procedure.