OD News Articles

3rd January 2005

Combining Cataract and Glaucoma Surgery

by David Stanfield, OD Chehalis, WA

Elevated IOP is common in the immediate post-op period of cataract surgery—although it is usually mild, self limiting and does not compromise vision. But even brief pressure elevation can irreversibly harm previously compromised optic nerves and visual fields. When cataract patients have glaucoma, combined cataract surgery and trabeculectomy may be the best treatment option to prevent damaging IOP spikes.

Several Benefits

In addition to preventing harmful pressure spikes, combined surgery provides other benefits:

  • Improved IOP control that may slow or stop progression of glaucoma.
  • Reduced or eliminated medications that save time, expense and risk of toxic side effects.
  • Reduced surgical risk and expense of separate procedures.
Additional Risk

Although combined surgery offers benefits it adds risk:

  • Longer visual recovery time
  • Increased risk of bleeding and infection
  • Lifetime risk of blebitis or endophthalmitis—add 1% chance for each year of expected remaining life
Not for Everyone

Although many people with cataracts and advanced glaucoma will benefit from combined cataract and trabeculectomy surgery, this option is not for everyone. Sometimes the risks are not worth the benefits. Examples include:

  • Patients with ocular hypertension and early to moderate glaucoma
  • Patients with controlled glaucoma, minimal or no damage to visual fields, happily tolerating treatment with medication

Patients need to actively participate in the decision. Those opting for cataract surgery alone will generally be given a small limbal or clear corneal incision to preserve the conjunctiva—should a trabeculectomy ever be necessary in the future.


Good Candidates

Good candidates for combined cataract surgery with trabeculectomy—Click for case study

  • advanced field and disc damage
  • progressive visual field loss or nerve change
  • multiple medications
  • medication side effects
  • non compliant with medicines
  • desire simpler routine

Good candidates for stand-alone cataract surgery—Click for case study

  • ocular hypertensives
  • early to moderate glaucoma well controlled with a single medication which is well tolerated

Pre-op Evaluation

When cataracts and glaucoma coexist, I suggest performing all tests necessary to decide for or against combined treatment including:

Visual fields
Visual fields—review recent maps (less than 9 months) to determine the glaucoma’s stability. If IOP has not been controlled, more recent data is better. Cataracts can cause a general depression of visual fields making interpretation tricky. I look for scotoma that have become larger and have found the pattern standard deviation to be a helpful indicator of progressive glaucomatous change.

Gonioscopy
Gonioscopy—helpful since the presence of a narrow angle will influence our surgical approach. In chronic angle closure glaucoma, without peripheral anterior synechiae, cataract surgery may deepen the angle and be all that is needed to lower IOP and stabilize the visual field.

IOP
IOP—pressure patterns over the last year are helpful. Combined surgery may be encouraged if pressure is increasing.

Optic Nerve
Optic nerve—should be evaluated for change. If optic nerve photos have been previously performed, a careful comparison can be made at the slit lamp. I also like to look for disc hemorrhages, which may indicate progressive damage. Imaging can be helpful but is not always necessary with good optic nerve drawings and photos.

Pre-op Counseling

The decision for or against combined surgery can only be made with patients’ input. A thorough review of all of the findings and careful explanation of risks and benefits is necessary—and can be time consuming. We only offer combined surgery in our Chehalis and Kennewick facilities to patients who can return for follow-up. Because of the time involved with pre-op counseling, these appointments are scheduled on non-surgery days.

Surgery

Combined cataract and glaucoma surgery involves a sequence of steps.

  • Conjunctival flap created by one of the following:

~ Limbus incision with the base attached at the fornix

~ Superior fornix incision with base attached at the limbus

  • Cataract scleral incision made and altered to create a filtration bleb and a rectangular scleral flap to protect the sclerotomy

  • Sclerotomy made with a scleral punch
  • Cataract removed and IOL placed
  • Scleral flap sutured with one of the following techniques:

~ Nylon sutures that can be cut with a laser 5-14 days post-op to open the flap and lower IOP


~ Releasable sutures under the corneal epithelium that can be removed later at the slit lamp to modulate IOP

  • Conjunctiva pulled over the scleral incision and held in place by absorbable sutures
Post-op Care

There can be a lot of post-op variability and patients who undergo combined surgery do not typically fall into predictable follow-up regimens. However, those with unremarkable findings are generally seen at the following intervals:

  • day 1
  • day 3-7
  • weekly for 1 month
  • bi-weekly for 1 month
Medications

When glaucoma patients have stand alone cataract surgery, we maintain their usual glaucoma meds and only make alterations as needed. Three meds that can worsen post-op inflammation and may need to be changed are:

 

Epinephrine Derivatives
Epinephrine derivatives (propine)—rarely used in clinical practice. Causes CME in some pseudophakes. When encountered, alternatives should be used.

Miotics
Miotics (pilocarpine)—increases inflammation and constricts the pupil making adequate dilation and cataract removal difficult. I like patients to be off miotics one week prior to cataract surgery and look for alternatives to control IOP. If no good options are available, or the glaucoma is too severe to discontinue meds, there is incentive to combine cataract and glaucoma surgery.

 

Prostaglandin Analogues
Prostaglandin analogues (xalatan, travatan and lumigan)—increase inflammation and cause CME in some psuedophakes. When patients have significant glaucoma, I usually continue these meds during the perioperative period. However, if inflammation or CME pose significant risk (i.e. diabetes, epiretinal membrane, iritis, or CME in fellow eye) I discontinue the drug or choose an alternative, depending on the clinical situation.

For a variety of reasons people undergoing treatment for ocular hypertension often have lower IOP after cataract surgery—which can last short or long-term. If they do not have field or disc damage, discontinuing glaucoma meds is reasonable.

Summary

When patients have cataracts and glaucoma, both conditions can sometimes be treated in the same surgery. Although this option is only available in our Chehalis and Kennewick facilities for patients who can return for follow-up, we are happy to discuss cases and help you decide what might be best for your patients. This may include recommending consultation with a local glaucoma specialist.

 

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