Pseudophakic Pupillary Block 

Updated: May 02, 2018
Author: Mitchell V Gossman, MD; Chief Editor: Douglas R Lazzaro, MD, FAAO, FACS 

Overview

Background

In pseudophakic pupillary block, the implanted intraocular lens (IOL) is partly or wholly involved in the obstruction of the aqueous flow through the pupil. This condition can develop days, weeks, months, or years after the lens implant surgery. If the condition is not recognized and treated early, it can lead to iris bombe, iridocorneal adhesion formation (starting at the periphery and extending toward the center), increasing intraocular pressure (IOP), and progressive damage to the optic nerve head.

The block is caused via mechanical closure of the pupil by the optic of the pseudophakos or by the development of synechiae between the iris and the artificial lens or remaining lens capsule. Pseudophakic pupillary block also can occur in patients with anterior chamber IOLs, either by direct blocking of the pupil by the optic or by the development of adhesions between the vitreous and the posterior iris. Closure of an existing peripheral iridectomy or an absence of a peripheral iridectomy may be a precipitating factor.

Pseudophakic pupillary block is shown in the image below.

Pseudophakic pupillary block precipitated by leaka Pseudophakic pupillary block precipitated by leakage of the incision line. This led to a chain reaction of forward movement of the posterior chamber lens, closure of the angle, intractable glaucoma, and iris-cornea touch over a wide area.

Results after surgery of the patient above are shown in the following image.

Same patient as in the image above, 1 month after Same patient as in the image above, 1 month after surgery. She underwent iridectomy at 3 places, separation of the iris from the cornea and the optic of the intraocular lens with viscoelastic material, and ab-interno filtration procedure at the 6-o'clock position, with erbium laser. The intraocular pressure is 13 mm Hg.

Pathophysiology

Extracapsular surgery that precedes the insertion of the IOL creates the following conditions that are conducive to inflammatory, proliferative, and fibrotic reactions: retention of a large part of the anterior lens capsule, retained lens matter in the fornices of the capsular bag, a tear of the posterior capsule, and lens-vitreous mix. The inflammatory reactions produce adhesions between the artificial lens and the uveal tissues, particularly the iris.

The so-called sulcus-supported lenses have a tendency to erode the ciliary processes and the ciliary body. In the process, a breakdown of the blood-aqueous barrier occurs. The optics of the sulcus-supported lenses have a greater tendency to partial or complete pupillary capture. The fibrous reactions in the capsular bag also can push the optic out of the bag, a process that may lead to the pupil capture.

Either of the following can push the lens optic firmly against the pupil, effectively blocking the forward movement of the aqueous and causing partial or complete pupil capture: the shallowness of the anterior chamber due to a wound leakage or pooling of aqueous in the vitreous pushing the lens optic forward.

In pediatric patients, the aforementioned factors play a part with much greater severity than in adults. Fibrin formation is encountered more often in children. There is a greater tendency for the optic to come out of the small capsular bag and become captured by the pupil. In neonates and young infants, there is a tendency for the iridectomy opening to shrink (like shrinkage of a continuous curvilinear capsulorrhexis) and ultimately close.

The net result of all these processes is iris bombe, anterior synechiae formation, glaucoma, and an increased resistance to the forward movement of the aqueous. Pupillary block can occur if the peripheral iridectomy and the pupil close by the above factors and one of the following is used: an IOL in the anterior chamber, an angle-supported lens, or an iris claw (Artisan) lens. In the pupillary area, the initial adhesions are formed between the pupil and the posterior capsule. As iris bombe develops, adhesions form between the anterior surface of the iris and the optic and the haptic of the IOL. The iris bombe may involve the whole iris; more often, it is multiloculated.

Examples of pseudophakic pupillary block in a pediatric patient are shown in the images below.

The patient is 6 years old. Closure of peripheral The patient is 6 years old. Closure of peripheral iridectomy, lens decentration, partial pupil capture, and adhesions between the optic and the iris have produced pupillary block. One of the loops has started cheese-wiring the iris. Iris bombe is all around. Iris incision line adhesions are visible. The intraocular pressure is normal.
With the help of a vitrector, the central part of With the help of a vitrector, the central part of the iris has been moved over and close to the optic. No attempt has been made to reposition the optic of the lens. The peripheral iridectomy is left as such. The iris bombe has settled nicely.

Epidemiology

Frequency

International

Pseudophakic pupillary block is not an uncommon condition. The exact incidence is not known, but it occurs more frequently in pediatric patients, especially those who are very young.

Mortality/Morbidity

Failure to relieve the pupillary block can lead to the development of chronic angle closure glaucoma and glaucomatous optic neuropathy.

Race

No predominance in specific races exists; however, Nd:YAG laser iridotomy may be difficult to perform in dark-skinned people.

Sex

No sexual predilection exists.

Age

The younger the patient, the greater the chance of a pseudophakic pupillary block. The space behind the iris contains the following reactive elements: anterior and equatorial lens capsular cells, remains of lens matter, ciliary processes and ciliary body, and posterior pigment epithelium of the iris. These elements can trigger inflammatory, proliferative, and fibrotic responses in the pupillary area and around the IOL. This ultimately can result in a pseudophakic pupillary block. Such reactions are uncommon in adults, especially after implantation in the bag. In the presence of an anterior chamber angle-supported lens or an iris claw lens, the absence or the closure of a peripheral iridectomy usually initiates the pupillary block.

 

Presentation

History

Problems begin after a variable period of days, weeks, months, or years after the operation.

Patients with pupillary block glaucoma usually note the sudden onset of symptoms, to include the following:

  • Pain in the affected eye

  • Unilateral headache

  • Blurred, steamy vision

  • Photophobia

  • Haloes around lights

  • Intense redness

  • Nausea and vomiting (sometimes)

Adults

In adults, deteriorating vision and increasing discomfort and pain are noticed and reported.

Children

The onset of this condition usually is rapid in pediatric patients, but it also can be insidious.

In the case of very young patients, parents notice a vacant look, a squint, and an inability to hold an object with the operated eye. They might notice pupillary changes in color and size and eye redness. The child frequently rubs the eye, refuses food, cries, and does not sleep soundly. The child might vomit for no obvious reason.

Older children report decreased vision and heaviness or pain in the eye.

Physical

A complete eye examination should be performed. Visual acuity usually is reduced depending upon the amount of corneal edema induced by the high IOP.

Pupillary examination

Various inflammatory and fibrotic forces may deform the pupil. The pupillary capture and decentration of the lens optic may further affect its shape.

High IOP may damage the pupillary sphincter, leading to a mid-dilated, nonreactive pupil. An afferent pupillary defect would not be expected immediately.

Blood, fibrin, Elschnig pearls, or thin or thick opaque fibrous membrane formation may cloud the pupil transparency.

Slit lamp examination

Conjunctival injection with a circumlimbal flush is observed.

The incision line might show iris incarceration, a sign of earlier leakage.

Varying degrees of corneal edema and striae may be present from the elevated IOP. Endothelial debris may be present depending upon the degree of inflammation.

The anterior chamber is shallow in the periphery but deeper centrally. Peripheral anterior synechiae (PAS) are evident. Iris bombe may be uniform or loculated. Iris atrophy may be present in areas where the lens optic impinges. Sites of erosion of the iris by the lens loops or the optic may be present.

The optic of the posterior chamber lens may be seen partially or completely captured by the pupil. One or two loops may be seen, which erode the pupillary margin. Pigment, exudates, foreign body giant cells, or an amorphous inflammatory or a noninflammatory membrane on the surface of the visible lens surface may be present.

If a peripheral iridectomy was performed previously, it may not be seen. It may be closed by blood or fibrin, or the area of the iridectomy may be scarred or closed with exudates or posterior adhesions with the lens capsule. Elschnig pearls, lens matter, or blood also can block the iridectomy. It can close if the adjacent iris becomes incarcerated in the incision line.

IOP

Normal in very early cases, but IOP rapidly rises as the condition advances. IOP in excess of 50 mm Hg is not unusual.

Gonioscopy

Cornea edema may not permit gonioscopy. When possible, it will show angle closure. If the process is long-standing, PAS may be visible.

Slit lamp examination may show iridocorneal adhesions.

Aqueous flare, cells, pigment, and exudates are seen.

Fundus examination

This examination may not be possible because of corneal edema. Usually, cupping is not evident until the IOP rise is long-standing. Sudden rises in IOP may cause pulsations in the central retinal artery and, if seen, should prompt emergent lowering of the IOP.

Causes

Risk factors for postoperative pupillary block include diabetes; short (axial length) eyes; and complicated surgical procedures preventing placement of the IOL in the capsular bag, including torn or disinserted posterior capsules; and vitreous loss. Poor capsular support may allow subluxation of the IOL with subsequent blockage of the pupil by vitreous, while placement of the IOL in the ciliary sulcus may allow for increased contact between the lens optic and the pupil. Placing an IOL upside down also may lead to pupillary block since most lenses are vaulted posteriorly; placing it upside down will force the optic anteriorly toward the pupil. Use of an undersized anterior chamber IOL may allow the optic to fall into the pupil, thereby creating block.

Inflammation

Acute inflammation can cause rapid occlusion of the pupil and the peripheral iridectomy with exudates.

Subacute and chronic inflammation may produce gradual formation of adhesions between the iris and the optic of the IOL, as well as the remaining capsular bag.

Physical blockage of the pupil

Physical blockage of the pupil may occur from many materials, including the following:

  • Blood

  • Fibrin

  • Vitreous

  • Lens material

  • Wound leak (may cause shallowing of the anterior chamber, allowing the IOL optic to move forward)

Proliferative

Proliferative causes may include the following:

  • Elschnig pearls blocking the peripheral iridectomy

  • Elschnig pearls closing the space between the iris and the IOL

Fibrotic changes

Formation of thick membrane in the pupillary area may occur.

Multifactorial

A combination of the above factors may cause this condition.

 

DDx

 

Workup

Laboratory Studies

The following laboratory studies may be used:

  • Blood sugar

  • Clotting and bleeding time

Imaging Studies

B-scan

Routine B-scan helps to identify the presence of a fallen nucleus, retained cortical matter, blood, and exudates in the vitreous.

Usually, choroidal hemorrhages can be seen easily.

A high-quality B-scan may identify anterior movement of the posterior vitreous compatible with aqueous misdirection.

Optical coherence tomography (OCT)

It helps to document the relationship between the periphery of the iris and the angle of the anterior chamber. It works best if the cornea is clear.

Ultrasound biomicroscopy

It is helpful in visualization of the structures behind the opaque iris. The position of the intraocular lens and the fluid space available behind the iris and around the ciliary body allow the peripheral anterior synechiae (PAS) to be easily seen.

 

Treatment

Medical Care

Medical treatment for acute pupillary block is designed to lower IOP, to quiet the eye, and to clear corneal edema, thereby allowing visualization for peripheral iridectomy.

Analgesics may be administered as necessary. Antiemetics also may be necessary if nausea and vomiting are problematic.

To control IOP, immediate treatment includes topical beta-adrenoreceptor antagonists (beta-blockers), alpha2-agonists, and carbonic anhydrase inhibitors. Acetazolamide may be administered by mouth or, if the patient is nauseous and vomiting, by 500 mg IV push. Intravenous or parenteral hyperosmotics (1 g/kg of body weight) may effectively lower IOP immediately but transiently. Available agents include glycerin and isosorbide solution 45% weight/volume for oral use or mannitol (ie, 100 g in 500 cc IV drip, 12.5 g in 50 cc IV push) for intravenous administration.

Dilatation of the pupil may help relieve pupillary block in pseudophakia or break posterior synechiae.

Inflammation accompanying acute angle closure may be treated with topical steroids, adjusting the dosage as needed to quiet the eye.

Surgical Care

The definitive procedure to break pupillary block is a peripheral iridectomy. This procedure usually can be accomplished using a laser (Nd:YAG, argon, or both), but, sometimes, in the case of severe inflammation, a surgical iridectomy may be necessary. Every attempt should be made to medically control IOP and to clear corneal edema before performing a laser iridectomy. Severe cases with membrane formation, nonclearing blood or inflammatory debris, or subluxed IOLs may require intraocular manipulation.

Peripheral iridectomy

A single peripheral iridectomy may be sufficient to break the block and to relieve the problem. A simple approach used by the author is as follows: A 1.5 mm tri-facet diamond knife is used to make a radial vertical incision in the periphery of the cornea. Iridectomy is done through it. The incision line is hydrated with saline. No suture is needed.

Multiple iridectomies may be necessary if multiple pockets of trapped aqueous are present behind the iris. This may be due to vitreous adherent to the iris or synechiae to the posterior capsule.

Laser iridectomies in inflamed eyes may be at risk for closure. If this is the case, they may be reopened or performed at another site. Surgical iridectomy may be more successful in such cases.

Fugo blade iridectomy: The Fugo blade is introduced through a 1 mm corneal incision. An opening of any desired size is made in the iris without pulling the tissue and without bleeding. Multiple iridectomies can be performed through the same incision, even on the opposite side of the limbus.

Fugo blade is very helpful in doing pupilloplasty and membranectomy, thus taking a large burden of management of difficult cases.

Freeing the pupil

Freeing the pupil involves the following:

  • Breaking iris-IOL synechiae

  • Removing inflammatory or fibrotic membranes

Removal of obstructive elements

Obstructive elements may include the following:

  • Blood

  • Lens matter

  • Elschnig pearls

  • Vitreous

  • Inflammatory exudates

Synechia and fibrotic membranes

The synechia and fibrotic membranes are best dealt with the Fugo blade. Any thickness of fibrous or fibrovascular scars can be incised or excised without bleeding and without any pull on the structures.

Vitrectomy

Vitrectomy may be necessary to remove vitreous from the anterior segment of the eye.

Manipulation of IOLs

Manipulation of IOLs involves the following:

  • Repositioning of IOLs

  • Explantation

  • Exchange

Filtration surgery

Filtration surgery is indicated if the anterior chamber angle fails to open following iridectomy, indicative of synechial closure, and IOP remains uncontrolled despite maximum tolerated medical therapy.

Transciliary filtration is an approach to manage glaucoma that departs from classic filtration surgery.[1, 2] This approach uses the tissue ablation and noncauterizing, hemostatic capabilities of the Fugo Blade (Plasma Blade). A nonbleeding micropore is created, which drains aqueous from behind the iris and into subconjunctival lymphatics. No peripheral iridectomy is needed.

Activity

The relief of symptoms and the resulting visual function determines the return to normal activity. Generally, no limitation of activity is required following laser iridectomy. If filtration surgery is required, limitation of activity may be necessary for 7-10 days.

 

Medication

Medication Summary

Patients with pseudophakic pupillary block may experience sudden and prolonged increases in IOP. As soon as the patient presents with this condition, the greatest concern is to lower IOP as quickly as possible. The near normalization of ocular tension reduces operative and postoperative risks. Almost all glaucoma medications may be used (see Glaucoma, Primary Open Angle), including beta-blockers and alpha2-agonists, but miotics should be avoided. In addition, acetazolamide (a carbonic anhydrase inhibitor) and mannitol (a hyperosmotic agent) may be required; analgesics and steroidal and nonsteroidal medicines also may be needed. Postoperative medicines depend on the progress; in most cases, it is the instillation of antibiotic-steroid and antiglaucoma drops.

Carbonic anhydrase inhibitors

Class Summary

By slowing the formation of bicarbonate ions with subsequent reduction in sodium and fluid transport, it may inhibit carbonic anhydrase in the ciliary processes of the eye. This effect decreases aqueous humor secretion, reducing IOP.

Acetazolamide (Diamox)

Inhibits enzyme carbonic anhydrase, reducing rate of aqueous humor formation, which, in turn, reduces IOP. Used for adjunctive treatment of chronic simple (open-angle) glaucoma and secondary glaucoma and preoperatively in acute angle-closure glaucoma when delay of surgery desired to lower IOP.

Hyperosmotic agents

Class Summary

Hyperosmotic agents lower IOP by moving fluid out of the vitreous into the bloodstream. Cannot be used chronically due to the risk of dehydration and electrolyte imbalance (particularly hypokalemia). Mannitol is a highly effective medicine of this group. Given intravenously and highly suitable for patients with nausea and vomiting caused by severe rise in the IOP. Extremely useful for administration just prior to the surgery. Glycerine is a nontoxic, readily available hyperosmotic agent, to be administered by mouth, to tide over a period of crisis. Isosorbide is an important hyperosmotic agent that can be given safely to patients with diabetes.

Mannitol (Osmitrol, Resectisol)

For IV use, it is the first DOC, especially for preoperative use. Effective for a direct osmotic action, since it is distributed only in the extracellular space and penetrates very poorly in to the eye. The kidneys rapidly excrete it. Not metabolized and therefore suitable for patients with diabetes. DOC as hyperosmotic, for IV use. Adverse effects include urinary retention (due to excessive diuresis), headaches, back and chest pain, chills and rigors, nausea, vomiting, confusion, pulmonary edema, hypokalemia, and hyponatremia.

Glycerin (Ophthalgan, Osmoglyn)

Nontoxic drug absorbed rapidly after taking by mouth. Stable and easy to store. Has a very unpleasantly sweet taste. Frequently induces nausea and vomiting. Should be given chilled and flavored with lime powder or fruit juice over cracked ice. Metabolized, producing hyperglycemia; therefore, it is less suitable for patients with diabetes. Adverse effects include diarrhea, back pain, confusion, and hyperosmolar coma.

Isosorbide dinitrate (Ismotic)

Given by mouth, increases osmotic pressure of plasma in 2 ways. Before it is absorbed from the intestines, draws water in to intestines and causes hemoconcentration. Secondly, when it actually enters the blood, the osmolarity is increased. Tastes much better than glycerine. Not metabolized; therefore, suitable for patients with diabetes.

Cholinergics

Class Summary

Help treat iris bombe by breaking iris IOL adhesions. Useful only in early cases. Once firm adhesions have been formed, it is difficult to break them by local medication.

Atropine ophthalmic (Atropair, Isopto, Atropisol)

Most potent parasympatholytic agent available. By paralyzing the sphincter pupillae muscle, helps dilate the pupil. Also paralyzes ciliary muscle. Effect lasts 7-10 days.

Sympathomimetic agents

Class Summary

When combined with parasympatholytics, provide the best chance of dilating the pupil.

Phenylephrine ophthalmic (Neo-Synephrine)

Selective alpha1-agonist induces mydriasis and vasoconstriction and reduces IOP. Maximum effect is produced in 30 min and remains for several hours. Combined with anticholinergic drugs, produces maximal mydriasis.

Corticosteroids

Class Summary

Inflammation is a constant accompaniment of patients with pseudophakic pupillary block. Steroid drops are very effective in reducing intensity of inflammation. Steroids control practically all aspects of the inflammatory process and immune response. Their main activity occurs at the actual site of inflammation; therefore, topical application in the eye suppresses inflammation.

Prednisolone acetate 1% (Pred Forte)

Most effective as anti-inflammatory agent on anterior segment of the eye. Frequent application needed to get maximal effect.

 

Follow-up

Further Outpatient Care

Regular, prolonged follow-up care is needed to observe and preserve the normal anatomy of the anterior segment, the clarity of the refractive media, and the maintenance of normal IOP. Monitoring of visual fields and visual acuity also is important.

Pediatric patients need special care during the postoperative period. They may need sedation or even general anesthesia for a proper and thorough examination.

Examine for uveitis by performing a careful slit lamp examination at every visit. In particular, examine for the presence of aqueous flare and cells and deposits on both the corneal endothelium and the optics of the IOL. The position of the IOL is monitored for centration of the optic, deposition of pigment or foreign body giant cells, and any adhesions that may be developing with the iris. Lifelong, regular follow-up care is important. Explain at every visit the current status of the eye. Strongly advise the patient to come for regular check-ups after 1, 2, or 3 months or longer (as the situation demands).

Inpatient & Outpatient Medications

Local and systemic medication depends on both the condition and the needs of a particular patient.

Most of the operated cases generally need mydriatics, anti-inflammatory medications (steroidal and nonsteroidal), and antiglaucoma medicines.

The frequency of local instillation, the dose of oral medication, and the length of medication are determined by the needs of the individual patient.

Transfer

An experienced surgeon and adequate facilities must be available to manage these patients. If not available, transfer of the patient is warranted.

Complications

Patients with glaucoma who are untreated or poorly treated experience loss of visual acuity and visual fields, which may result in total visual loss.

Corneal decompensation may result from endothelial damage caused by the sudden rise in IOP or prolonged uncontrolled IOP. It also may result from contact with an anteriorly displaced IOL.

Uveitis may result from iris and/or ciliary irritation from the IOL or vitreous, as well as breakdown of the blood-aqueous barrier due to acute glaucoma. Surgery may lead to prolonged inflammation.

Chronic inflammation and/or vitreous in contact with the iris may lead to the development of cystoid macular edema with reduced visual acuity, even after the IOP problem has been corrected.

Prognosis

The earlier the condition is detected and adequately treated, the greater the chance of a full recovery. Once it is found that the pupillary block is not amenable to conservative treatment and an early surgical correction is instituted, the chances of recovery are excellent.

Patient Education

All patients undergoing intraocular surgery should be advised to contact the surgeon immediately if they experience pain or sudden decreases in vision in the postoperative period. These signs could indicate the development of pupillary block and acute glaucoma.

Patients should be aware of the need for regular follow-up visits to detect such problems before they result in serious vision-threatening conditions.