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The Management of Coexisting Cataract and Advanced Glaucoma

Carla I. Bourne, MD; Bradford J. Shingleton, MD; and Joel S. Schuman, MD, FACS

Cataract and glaucoma are common entities that frequently coexist, especially in older individuals. The management of either requires consideration of both, particularly when surgical intervention is contemplated. The decision for cataract or glaucoma surgery, or combined cataract and glaucoma surgery, necessitates evaluation of the need for visual rehabilitation and the urgency of intraocular pressure (IOP) control.

Cataract surgery is considered when the patient complains of deterioration of vision to a point where it interferes with the ability to read, write, and perform other activities of daily living and when examination of the patient’s eye reveals cataract as the source of some or all of these visual complaints. The surgeon must recall, however, when determining the cataract’s functional effect, that a small cataract may have a disproportionately large effect in the glaucomatous eye, especially in the presence of compromised visual field.

Glaucoma subtype, IOP control, current ocular hypotensive therapy, and the severity of glaucomatous optic nerve damage each has an impact on the decision regarding the role of glaucoma surgery in the patient with cataract. History of prior laser trabeculoplasty (LTP), laser iridectomy, or incisional glaucoma surgery are factors involved in the surgical decision making for these patients. It may also be difficult to determine the extent of glaucomatous damage due to the impact of the cataract on optic nerve examination and visual field testing.

There are other factors that need to be considered when dealing with simultaneous management of cataract and glaucoma. These include whether 1 or 2 surgical procedures are warranted and if performing 2 procedures, which should be done first (Table 62-1). Both short- and long-term planning is essential in order to determine if a filter or nonfilter procedure would meet goals to prevent disease progression and what would be the most suitable intraocular lens (IOL) implant given other ocular pathology. This detailed evaluation is necessary as the risks and complications are greater with cataract surgery in glaucomatous eyes than in nonglaucomatous eyes.

Surgery in glaucomatous eyes involves special considerations. Conjunctival scarring from previous surgery increases the difficulty of conjunctival dissection and increases the risk of conjunctival tear or buttonhole. Altered conjunctiva due to chronic glaucoma medication use or topical allergy may compromise conjunctival mobilization and lead to increased bleeding. A small pupil due to long-term use of miotics and a shallow anterior chamber in highly hyperopic/nanophthalmic eyes increases the difficulty of capsulorrhexis and phacoemulsification. Significant anterior synechiae may preclude anterior chamber IOL implantation. Eyes with pseudoexfoliation have weak zonular attachments, which increase the risk of zonular dialysis and vitreous loss during surgery. A high preoperative IOP, with a rapid reduction in IOP at the time of surgical entry into the eye, predisposes to suprachoroidal hemorrhage. The incidence of cystoid macular edema may increase after cataract surgery in eyes on multiple glaucoma medications. This may be most apparent in eyes on prostaglandin agonists that have complicated surgery with violation of the posterior capsule and vitreous loss.

Glaucomatous eyes with visually significant cataract in which the IOP is well controlled on 1 or 2 medications can be considered for cataract extraction alone or combined with microinvasive glaucoma surgery (MIGS). Additional indications are presented in Figure 62-1. Studies have demonstrated that small-incision phacoemulsification can yield improved long-term IOP control. Shingleton and colleagues¹ showed a statistically significant IOP decrease of 1.8 ± 3.5 mm Hg 5 years after cataract surgery alone. Issa and colleagues² suggested that IOP reduction after cataract surgery is greatest in eyes with higher IOP and narrower angles preoperatively. Poley and colleagues³ reported significantly greater IOP reduction in glaucomatous and nonglaucomatous eyes with higher preoperative IOPs. Mean IOP reduction approached 10 mm Hg in eyes with preoperative IOPs higher than 28 mm Hg. Shingleton and colleagues⁴ confirmed significantly greater IOP reduction in pseudoexfoliation eyes with higher preoperative IOP. It must be noted that a long-term decrease in glaucoma medication requirement has not been substantiated and by year 5, most eyes require a return to preoperative medication levels.^1,5,6 If cataract surgery alone is performed, it is best to approach the eye from the temporal aspect to preserve superior conjunctiva if filtration surgery is needed in the future. Standard phacoemulsification techniques are used. We recommend the use of nonsteroidal anti-inflammatory drops preoperatively to decrease the risk of postoperative cystoid edema, and we do not routinely stop glaucoma medications preoperatively.

LTP can also be considered in conjunction with cataract surgery in eyes with borderline control of IOP. It can be performed prior to or after cataract surgery. LTP may be slightly more effective in phakic eyes, but clinically significant IOP reduction can also be achieved in pseudophakic eyes.^7,8

During the preoperative evaluation, the advantages and disadvantages of cataract surgery alone must be weighed because IOP spikes may occur in both the early and long-term postoperative periods (Table 62-2). This can be due to retained viscoelastic, trabecular meshwork (TM) damage, collapse in the area of incision, residual pigment or cortical debris, breakdown of blood-aqueous barrier, and corticosteroid use. This is particularly important for patients with significant glaucomatous optic atrophy who might not be able to tolerate significant IOP elevation, even for a short time.

As early as 1 hour postoperatively, there have been reports of IOP elevation as high as 13.4 mm Hg in normal eyes,⁹ and in glaucomatous eyes, there is tendency for this to be a greater and more frequent increase. IOP elevation may peak in the 2- to 8-hour range after cataract surgery,10,11 and the elevation may extend into the first postoperative day. Shingleton and colleagues¹² reported that 8.1% of normal eyes compared with 15.6% of glaucomatous eyes had IOPs of higher than 30 mm Hg on postoperative day 1 following uncomplicated cataract surgery. Prophylactic use of aqueous suppressants, alpha-agonists, and miotics at the time of surgery can help moderate postoperative IOP elevation but there is no consensus of opinion as to which medicine, if any, is more efficacious.^13–16 If IOP elevation is of particular concern postoperatively, as may be the case in a patient with significant disc damage, IOP should be checked on the day of surgery. If significant IOP elevation occurs, we favor release of aqueous via the paracentesis and reinstitution of aqueous suppressants and alpha-agonists, as needed. Aqueous release is done at the slit lamp under topical anesthesia and with sterile precautions. It is important to recheck the IOP 15 to 30 minutes after aqueous release as the IOP can respike, necessitating a repeat tap.¹⁷

At the other extreme, early hypotony (30 minutes postoperatively) can also infrequently occur, complicating healing if prolonged. Fortunately, when transient, it has not been shown to increase susceptibility to choroidal effusion, hemorrhage, or infection.18

A poorly dilating pupil presents special challenges for the cataract surgeon and is a common occurrence in the glaucoma patient. It can be associated with long-term miotic use, older age, alpha-blocking agents, pseudoexfoliation, pupillary membranes, iridoschisis, anterior segment dysgenesis, noniatrogenic/iatrogenic trauma, and a poor preoperative dilation regimen. Table 62-3 provides an outline of strategies for managing a small pupil during cataract surgery (Figures 62-2 and 62-3).

Intraoperative Floppy Iris Syndrome

Intraoperative floppy iris syndrome is a well-documented issue due to use of alpha-1 blocking agents including tamsulosin (Flomax), terazosin (Hytrin), doxazosin (Cardura), alfuzosin (Uroxatral), saw palmetto (herbal remedy), psychotropic drugs (mianserin—antidepressant), and antihypertensives (prazosin, guanadrel [Hylorel], labetalol). It may also occur with finasteride, which acts by inhibiting type II-5 reductase. Discontinuing the medications may improve but not eliminate intraoperative floppy iris syndrome, and it may occur with Flomax discontinued 1 year or more before cataract surgery. Variable incidence of complications has been documented,¹⁹ but the intraoperative findings of poor dilation, floppy iris, iris prolapse, and progressive miosis have been reported to be as high as 63%.20 Management is similar as for a poorly dilating pupil with the incorporation of special phacoemulsification techniques (Table 62-4).

Zonule weakness may present in up to 2.5% of pseudoexfoliation eyes and may lead to a higher rate of complicated surgery necessitating vitrectomy.4,21–23 Preoperative and intraoperative clues to zonule weakness are presented in Table 62-5 and Figure 62-4.

When anticipating the possibility of dealing with an unstable nucleus due to zonule weakness, the surgeon may consider a posterior limbal incision or scleral flap to enable an easy transition to extracapsular cataract extraction, if required. Effective hydrodissection is critical to achieve free rotation of the nucleus within the capsular bag and to minimize extension of aspiration forces to the capsular equator during phacoemulsification. Capsule retractors, capsule tension rings (Figure 62-5), or capsule retaining segments can be used to distribute forces and to oppose capsule constriction and zonule separation during phacoemulsification. Anterior chamber, iris-sutured, or scleral-sutured IOLs may be required if capsule/zonule support is inadequate.

As mentioned previously, patients with narrow angles may benefit the most from cataract extraction by opening of the angle with resultant decline in IOP in nonsynechial angle closure.2 With synechiae present, intraoperative goniosynechialysis at the completion of cataract surgery can be performed to aid results.^24,25

Nanophthalmic and high hyperopic patients often have deep set eyes, small orbits, tight lids, high lens/eye volume ratio, small corneas, thick sclera, and miotic pupils, leading to potentially complicated surgery. Because of space constraints, surgeons may consider using a small-volume anesthetic block with external compression. Keratome entry into the anterior chamber should be anterior to avoid iris prolapse. Healon V (Alcon Laboratories) can be effective in maintaining anterior chamber depth and flattening the lens/iris contour. It may be necessary to perform a pars plana vitrectomy or vitreous tap to achieve a satisfactory anterior chamber depth that will permit safe creation of a capsulorrhexis. Pupil support devices are often helpful. Following completion of the cataract surgery, intraoperative gonioscopy is indicated to assess for residual angle closure that might be amenable to intraoperative goniosynechialysis. Postoperatively, these eyes are at a higher risk for aqueous misdirection.

Effective IOP reduction in acute angle-closure glaucoma has been documented with primary phacoemulsification and IOL implantation.26–29 In some cases, IOP elevation and vision improvement may be achieved with fewer interventions by this approach than by the more conventional program of initial medical therapy followed by laser iridectomy and subsequent cataract surgery.

Combined Cataract and Glaucoma Surgery

Cataract and glaucoma surgery is commonly performed in the same session in those eyes with visually significant cataract coupled with glaucoma that is advanced, poorly controlled, or requires multiple medications. Combined surgery can also be performed to reduce the risk of an IOP spike following cataract surgery in eyes with severely compromised optic nerves, where such an IOP spike increases the risk for further loss of visual field. Other indications are presented in Figure 62-6. The combined procedure offers the advantage of relatively rapid visual recovery and reasonable control of IOP. Visual rehabilitation is generally faster than with a 2-stage procedure, and control of IOP, especially with the use of antimetabolites, approaches that of filtering surgery alone.

Combined surgery, however, is more time consuming and technically challenging than cataract surgery alone. With greater potential complications, combined procedures require more intensive postoperative care. Combined cataract and trabeculectomy surgery can be performed via separate or single incisions. Studies indicate that IOP control is essentially equivalent for each approach.30–35 Advantages and disadvantages of combined cataract and glaucoma surgery are listed in Table 62-6.

Separate Site Incisions

In this approach, cataract surgery is typically performed first via a temporal incision followed by the surgeon’s preferred technique for superior trabeculectomy with or without antimetabolite. A 10-0 nylon suture should be placed at the cataract incision to maintain chamber stability during the trabeculectomy phase and to facilitate postoperative manipulation of the developing filtration bleb.

An alternative approach is to begin with the trabeculectomy portion superiorly, completing placement and removal of antimetabolite and creation of the partial-thickness scleral flap prior to phacoemulsification from the temporal aspect. The sclerectomy, iridectomy, and flap closure are then completed superiorly in a standard fashion after the cataract is removed.

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