Phacoemulsification With Intraocular Lens (IOL) Implantation Periprocedural Care

Cataract surgery | https://youtu.be/P_9tH1aQTEs

IOL Options | https://youtu.be/_GMxn1VyiNU

Phacoemulsification with Monofocal Implant | https://youtu.be/jgoBQzPm4ek

Phacoemulsification with Toric Implant | https://youtu.be/DuquW4AoNMo

Phacoemulsification with Multifocal Implant | https://youtu.be/2Zl7UI7BJwo

Special devices needed for the procedure are as follows:

• Iris hook

• Pupil stretcher

• Capsular tension ring

Modern extracapsular cataract extraction surgery involves the removal of the lens fibers, which form the nucleus and cortex of the cataract, leaving the posterior epithelial capsule to hold the new artificial intraocular lens (IOL) and keep the vitreous humor away from the anterior chamber. ^[1]

Ocular lenses

Ocular lenses transmit and refract light to diverge or converge the beam to change the eye's optical power.

Intraocular lenses

Intraocular lenses (IOLs) are plastic lenses that are permanently implanted into the eye, typically at the time of cataract surgery. IOLs also may be injected into patients who retain their native crystalline lens to correct refractive errors.

Phacoemulsification surgical devices

Different manufacturers utilize a peristaltic, Venturi, or a combination of both peristaltic and Venturi systems. Technologic advances have reduced the amount of phaco energy delivered to achieve phacoemulsification. Manipulation of fluid dynamics, surgical tip oscillations, and power delivery leads to shorter surgical times and lesser surgical trauma.

Ophthalmic viscosurgical devices

Cataract surgery is performed in a closed, fluid-filled medium, dependent upon fluid flow. Ophthalmic viscosurgical devices (OVD) are utilized to maintain a safe environment for successful phacoemulsification.

OVDs can best be classified in a system based on zero shear viscosity and relative degree of cohesion or dispersion, as these two factors play essential roles in our surgical use of OVDs.

Higher viscosity cohesives

Higher viscosity cohesives are best used to create and preserve spaces, displace and stabilize tissues, pressurize the anterior chamber, and provide a clear view of the posterior capsule during phacoemulsification. Their disadvantages include rapid removal from the anterior chamber during phacoemulsification or irrigation and aspiration leading to suboptimal endothelial protection, inability to partition spaces, and increased difficulty for removal at the end of the procedure.

Lower viscosity dispersives

Lower viscosity dispersives best are used to protect the endothelium (because it remains adjacent to the corneal endothelium throughout the phacoemulsification) and selectively move, isolate, and partition spaces. Its disadvantages include its inability to maintain spaces or stabilize, and its irregular fracture boundaries, which obscure the view of the posterior capsule.

Anesthesia

Topical and intracameral anesthesia are the preferred routes of delivery in cataract surgery. Other routes of delivery may have their use in specific cases.

Topical anesthesia

Topical anesthesia consists of analgesia. It blocks the production and not the transmission of pain sensation. Motor, thermal, and tactile fibers are not suppressed. It is suitable for cataract surgery because akinesia is not required by phacoemulsification. Safe and effective treatments include repeated eyedrop instillations, gel application, and a drug-soaked sponge.

Ester-bound compounds (tetracaine, proparacaine, benoxinate) have faster and shorter action than amide-bound compounds (lidocaine, bupivacaine, ropivacaine, mepivacaine). Different anesthetic drugs give similar results. The author prefers topical proparacaine eyedrops supplemented with an intracameral delivery of lidocaine. Patient selection or intravenous sedation is less used with experience. Side effects of topical anesthesia consist of immediate and postoperative ocular dryness lasting up to a few weeks. ^{[3, 4]}

Intracameral anesthesia

Intracameral injections that are proven safe and effective include intracameral injection of drug dilutions or anesthetic viscoelastic substances. The author prefers to supplement topical proparacaine with preservative-free lidocaine 1% intracameral injection. Intracameral anesthesia has been proven safe for intraocular structures, although its necessity remains controversial. ^[5]

Peribulbar anesthesia

Peribulbar anesthesia rarely is necessary, except when excessive conjunctival manipulation is performed or when converting to a large incision extracapsular cataract extraction procedure. It is performed using a short 1-inch 25-gauge or 27-gauge needle inserted external to the muscle cone underneath Tenon's capsule. This theoretically is safer than retrobulbar anesthesia since it eliminates the risk for optic nerve injury or intradural injection.

Retrobulbar anesthesia

Retrobulbar anesthesia provides excellent ocular akinesia and anesthesia. This may be used with or without regional anesthesia of cranial nerve VII.

Oral sedation

A light sedative may be taken by mouth to facilitate relaxation during the procedure. The patient is fully awake and can follow verbal commands.

Anxiolysis

A peripheral intravenous line is placed, and very light sedatives are given to decrease anxiety. This is the lightest level of general intravenous anesthesia.

Intravenous sedation

This is similar to anxiolysis GA; however, more intravenous sedatives are given. There is a higher risk for morbidity with this type of delivery due to the potential awakening, which may occur during the procedure once a patient falls asleep.

Laryngeal mask anesthesia (LMA)

Controlled delivery of inhalational and intravenous anesthetics. They are used for surgeries limited to 60-90 minutes. This may be useful in complicated cataract surgeries requiring multiple procedures.

Endotracheal tube anesthesia (ETTA)

Absolute controlled delivery of inhalational and intravenous anesthetics. They are used for surgeries estimated to last longer than 90 minutes.

Temporal

This is the most common position of most surgeons who perform phacoemulsification. The patient is lying supine on a surgical table. The surgeon is seated facing the temporal cornea. This presents the advantage of having better surgical exposure due to the avoidance of the orbital rim superiorly. For a right-hand-dominant surgeon, this would be the standard approach for the left eye. For a left-hand-dominant surgeon, this would be the traditional approach for the right eye.

Superotemporal

This is another common position of surgeons who perform phacoemulsification. The patient is lying supine on a surgical table. The surgeon is seated facing the superotemporal cornea. This presents the advantage of having better surgical exposure due to avoidance of the nose. For a right-hand-dominant surgeon, this would be the standard approach for the right eye. For a left-hand-dominant surgeon, this would be the traditional approach for the left eye.

Superior

More senior surgeons and posterior segment surgeons may be seen performing phacoemulsification using the superior approach. This probably is  retained by habit from transitioning from a superior approach while performing large-incision manual expression extracapsular cataract extraction (ECCE) or retina surgery. The phacoemulsification handpiece usually enters the eye via the temporal or superotemporal cornea, while the second instrument enters the eye via the nasal or superonasal cornea.

Surgical Preparation

After applying topical anesthetic, eyelashes are scrubbed with an antiseptic solution. A facial prep with Betadine follows. Sterile disposable drapes are meticulously applied, and a transparent sterile drape is placed on the eye, ensuring eyelashes are moved out of the surgical field.

The following medications should be stopped 1 week before planned cataract surgery:

• All blood thinners (aspirin, aspilet, clopidogrel, heparin, enoxaparin, ardeparin, danaparoid, warfarin, vitamin E, ginkgo biloba)
• All prostate medications (tamsulosin [Harnal], tamsulosin hydrochloride [Flomax], terazosin hydrochloride [Hytrin], dutasteride [Avodart], dutasteride/tamsulosin [Duodart], finasteride [Proscar], among others)

A preoperative examination is used to determine if there is a need for iris hooks, Malyugin rings, triamcinolone acetonide, Ozurdex dexamethasone implants, and other devices.

Systemic evaluation with or without laboratory diagnostics and cardiopulmonary clearance may be required. Different biometry packages would include the following:

• Optical biometry
• Specular microscopy
• Corneal topography
• Macular optical coherence tomography (OCT)
• Optic nerve OCT
• Dilated color fundus photos