Cataract Surgery: Indications

Cataract Surgery

• Cataract surgery involves the surgical removal of a cataract that causes visual or ocular health problems.
• The procedure usually includes implantation of a plastic intraocular lens (IOL).
• Cataract surgery is a common surgery with a very high success rate.
• It is also one of the oldest types of eye surgery.
• Cataract surgery addresses the third leading cause of preventable blindness in the United States.

General Indications

• Indicators include a decrease in visual acuity, for which insurance typically starts paying if BCVA decreases to 20/40 or worse, or when BCVA is reduced by two lines.
• Issues with glare such as difficulty seeing when LED car headlights shine, can be an indicator.
• Best Corrected Visual Acuity (BCVA) being reduced by two lines on glare testing is also an indicator.
• Phacomorphic or Phacolytic glaucoma and narrow angles could lead to surgery.
• Decreases in vision that impede activities of daily living also may require surgery.
• Special attention should be given to the minimum BCVA needed to drive.
• Reduced views of the posterior segment could be a sign

Absolute Contraindications

• Active proliferative retinopathy is a contraindication.
• Rubeosis Iridis is a contraindication.
• Neovascular glaucoma is a contraindication.
• Active uveitis is a contraindication.

Relative Contraindications

• Chronic uveitis is a relative contraindication and requires waiting until there are no flare-ups for a while, along with aggressive pre- and post-op topical steroid usage.
• Corneal guttata is a relative contraindication due to the high risk of corneal edema post-op, but it may be controlled with a modified surgical technique.
• Non-proliferative diabetic retinopathy is a relative contraindication.
• There is an increased risk of post-op macular edema, and co-management with a retinal specialist should be considered.
• Other retinal diseases may require clearance from a retinal specialist before surgery.

Pre-Operative Exam

• In additionally to a comprehensive eye exam, a detailed case history should be performed, focusing on the patient's visual complaints and how they affect their daily life.
• Glare testing, potential acuity testing, B scan if the cataract is advanced and posterior pole views are difficult, and A scan to measure the axial length for IOL power calculations may reveal important information.
• Corneal topography should be included.
• Dry eye testing should be completed, especially in patients with dry eye complaints.

Brightness Acuity Tester (BAT)

• Brightness Acuity Tester (BAT) is an instrument that can check functional VA in various light conditions.
• BAT can also be done with a transilluminator
• Indications include corneal opacities, cataracts, Posterior Capsular Opacities (PCO), vitreous opacities, and maculopathies.
• Pharmacologically dilated pupils are a contraindication.

BAT Results Interpretation

• No change or only a 1 line decrease in acuity indicates normal function.
• Two lines or greater decrease in acuity indicates the presence of a media opacity.
• Any improvement in visual acuity indicates uncorrected refractive error.

Potential Acuity Meter (PAM)

• Potential Acuity Meter (PAM) is a slit lamp mounted device that can determine visual acuity if no media opacities existed.
• An indication of PAM existence would be Sectoral Media Opacities
• Uniform, dense media opacities, poor dilation, and nystagmus are all contraindications.
• Improvement of 20/40 VA or 4+ lines indicate clinically significant benefit to surgery

Cataract Surgery and Glaucoma

• Cataract surgery can reduce IOP because of decreased volume within the globe.
• Cataract surgery can move the iris posteriorly, away from the trabecular meshwork.
• Cataract surgery is sometimes combined with glaucoma surgery.
• The goals for surgery are to either reduce the number of drops taken or to preserve vision.
• The type of surgery chosen will depend on the severity of the glaucoma, and the surgeon’s preferences.
• Prostaglandins may need to be discontinued pre- and post-operatively due to the increased risk of inflammation and macular edema.
• A non-prostaglandin prescription between 1 week pre-op and 6 weeks post-op may be given.

Pre-Operative Discussion

• Discuss the procedure with the patient to get their written, informed consent
• Thorough review of any visual demands the patient may have
• Ensure the patient knows that they may still need glasses for some tasks afterwards.
• Review all the options for the correct type of IOL.

Types of IOLs by Location

• Posterior Chamber IOL is the most common and preferred choice because they are usually fixated within the capsular bag.
• Sometimes, however, they are fixated into the ciliary sulcus if capsular bag ruptures or zonules become weak.
• Anterior Chamber IOL is attached to the iris and covers the pupil, and are only indicated if the posterior chamber is not an option.
• This type of IOL requires prophylactic LPI to prevent angle closure, and dilation is contraindicated in these patients.

Monofocal IOL

• Monofocal IOLs are placed in the ciliary sulcus behind the iris or within the capsular bag.
• These are fix-focus lens usually set at distance
• Monofocal can create monovision like in contact lenses, but will still require glasses occasionally.
• These are better for people who want sharp vision at a particular distance, and a best option if patients have decreased vision from ocular disease.

Toric IOL

• Toric IOL lens are spherical like monofocal IOL's, but corrects for astigmatism.
• Placement of Toric IOL's becomes very important
• Best for patients where corneal astigmatism makes a significant contribution to the patient's refractive error, but may also work in patients with reduced vision

Light Adjustable Lenses (LAL)

• Light Adjustable Lenses are a new type of monofocal IOL.
• Lens material is sensitive to UV light, which can change the lens's shape and, therefore, its power.
• LAL allow for fine adjustment of the prescription after cataract surgery without additional surgery
• LAL can be contraindicated in those taking photosensitive medications and macular disease
• Note: Patients require UV-blocking material to prevent unintended adjustments to the cornea, with "initial light treatment" ~2-3 weeks after surgery, with a "secondary light treatment" ~3 days after initial treatment, and a final “additional light treatment” ~3 days after the prior treatment

Multifocal IOL

• Multifocal IOLs contain multiple zones which allow for clear distance, near, and sometimes intermediate vision at specific focal points.
• Some designs are pupil dependent.
• Designed for those who need workable vision at multiple distances.
• Possible problems include glare, halos, and contrast sensitivity
• Should not be recommended for patients with vision loss due to posterior segment disease.

Accommodating IOL

• Accommodating IOL mimic a patient's natural accommodation through flexible haptic pates, providing up to +1.50 D of accommodation.
• Accommodating IOL's are good for patients who need good distance and intermediate vision

Extended Depth-of-Focus (EDOF) IOL’s

• Extended Depth-of-Focus (EDOF) IOL’s are designed to create an elongated focal point (rather than a single or multiple discrete focal points), allowing for depth of focus.
• They eliminate halo and ghosting side effects common with multifocal IOL’s.
• Allow for workable distance and intermediate vision
• Can cause increased visual aberrations that may decrease overall vision quality
• Can be combined multifocal IOL’s to increase the range of workable vision.

Other IOL Design Elements

• IOL design elements can include a variety of materials.
• Typically made of PMMA, silicone, or acrylic.
• Acrylic is the most popular due to foldability, ability to create different optical designs, and reduced occurrence of PCO.
• Can contain filters such as UV light Filtering which is standard and reduces risk of solar retinopathy and macular edema, and even blue-blocking lenses.
• Most lenses are aspheric in design to reduce aberrations.
• IOL designs may be mixed and matched to provide optimal vision for a patient.

Pre-Op Preparation

• Drops typically started two days before surgery.
• Includes antibiotic QID until 1-week post-op, NSAID QID until 1-month post-op, and steroid QID until 1-week post-op, then tapered to TID for 1 week, then BID for 1 week, then QD for 1 week.
• Artificial tears can aid in the healing process.
• Some surgeons may perform intravitreal injection of these medications, eliminating need for pre- and post-op drops.
• Patient also sometimes gets a fox shield to wear the night after surgery to prevent eye rubbing.

Starting the Procedure

• Surgery takes approximately 5-15 minutes.
• Anesthesia is required.
• Peribulbar or retrobulbar injection can be administered.
• Incision is near the limbus with approximately 3-10 mm in size.
• Incisions are usually self-sealing would.
• Viscoelastic will be dispensed into the globe to keep its shape during surgery.
• Can be accomplished with variety of surgical techniques

Intracapsular Cataract Extraction (ICCE)

• Intracapsular Cataract Extraction (ICCE) involves when cataract is removed in one piece with the lens capsule.
• Typically done when patient's zonules are damaged.
• Disadvantages include need for a large corneal incision, a high risk of vitreous prolapse and post-operative complications, as well as limited options for IOL implantation.

Extracapsular Cataract Extraction (ECCE)

• Extracapsular Cataract Extraction (ECCE) involves breaking the cataract into smaller pieces that is removed from the eye.
• An opening is first created in the anterior capsule (capsulorhexis)
• Can be accomplished using two strategies: nuclear expression or phacoemulsification.
• Nuclear expression involves the nucleus expressed from capsular bag and removed in one piece.
• Phacoemulsification is the most common technique in which a cataract is emulsified with ultrasonic waves.

Femtosecond Laser-Assisted Cataract Surgery (FLACS)

• Femtosecond Laser-Assisted Cataract Surgery (FLACS) uses ND:YAG Laser to create the corneal incision, the capsulorhexis, and break up the lens particles.
• FLACS offers more precision compared to phacoemulsification, and it may also correct up to 1 D of corneal astigmatism (astigmatic keratomy).
• FLACS is only contraindicated in small, non-dilating pupils.
• Outcomes and complication rates are similar compared to phacoemulsification.
• Laser usage is generally not covered by insurance.

Limbal Relaxing Incisions (LRIs)

• Limbal Relaxing Incisions (LRIs) include placing superficial incisions in the cornea, close to the limbus, to reduce astigmatism.
• Incision typically placed on the steep meridian
• Used with asymmetric or irregular astigmatism.
• Can treat up to 3 diopters of astigmatism
• Typically causes scarring and (minimally) increases risk of infection

Intraoperative Complications

• There is potential of subconjunctival hemorrhage, hyphema, an increased risk in those on anticoagulants which can be prevented by stopping the medications 5 days pre-op and resuming 1-day post-op with clearance from PCP or cardiologist.
• Capsular rupture/zonule breakage are risks, with higher risk in patients with pseudo-exfoliative syndrome.
• Possible risk include miosis and Floppy Iris Syndrome .

Floppy Iris Syndrome

• Floppy Iris Syndrome occurs with Iris prolapse through the surgical incision because of progressive pupil constriction during surgery.
• Patients taking tamulosin for BPH are at much higher risk.
• Preventative techniques include Discontinuing medications up to 8 weeks before surgery, use epinephrine to dilate pupil, improved surgical technique, and Iris retractors.