Jeffrey R. SooHoo, MD; Joel S. Schuman, MD, FACS; David L. Epstein, MD, MMM; Ian Conner, MD, PhD; and George Ulrich, MD, FACS
Angle-closure glaucoma that occurs spontaneously may be acute or subacute (see Chapter 25). In both types, the sole cause of rise in pressure is closure of the angle, but the clinical manifestations are somewhat different. In acute angle-closure glaucoma, symptoms appear suddenly and dramatically. In subacute angle closure, symptoms are less intense and dramatic and tend to resolve spontaneously. With recurrent episodes, permanent areas of synechial closure may develop. Hence, in the sense that episodes tend to recur and angle changes tend to evolve without intervention, there is some chronicity to the condition.
Distinct chronic angle-closure glaucoma, also referred to as silent chronic angle closure (see Chapter 23), is a separate entity. It develops silently without symptoms. The process may be due to sustained yet potentially reversible appositional closure or to synechial closure.
This chapter will discuss acute angle-closure glaucoma, although many of the same considerations apply to subacute and related chronic angle-closure glaucoma.
DIAGNOSIS
In acute angle-closure glaucoma, the angle is predisposed to the dramatic event of angle closure by being extremely narrow in the whole circumference even before closure occurs (Figure 24-1). During an attack, all or most of the angle closes and intraocular pressure (IOP) can reach extremely high levels. Acute angle closure represents a small fraction of all the glaucomas, but it is an important variety because it represents one of the true ophthalmic emergencies. If not diagnosed and treated promptly and properly, it can result in irreversible blindness in a matter of hours to days. The diagnosis is usually not difficult to make, but certain points deserve emphasis.
Acute Onset
An attack of acute angle closure has the most precipitous onset of any disorder involving the anterior segment. A quiet eye may change from a normal functioning state to a state of violent glaucoma in 30 to 60 minutes. No other disorder involving the anterior segment comes on with such rapidity.
By obtaining an accurate history of acute onset, there is a strong presumption, even before the patient is examined, that the diagnosis will prove to be acute angle-closure glaucoma. A careful history frequently discloses that weeks or months before the severe acute attack, there were premonitory, self-limited episodes of aching and visual blurring, each lasting a few hours and occurring with increasing frequency until the sudden development of the latest, most severe attack.
Dilation of the Pupil
In acute angle-closure glaucoma, there is most often a degree of intermediate dilation of the pupil. The diameter of the pupil can range from 3 to 8 mm. Reaction of the pupil to light is usually minimal or absent.
Shallow Anterior Chamber
In most cases of acute angle-closure glaucoma, the anterior chamber is very shallow axially. In exceptional cases, the axial depth of the anterior chamber may be normal (plateau iris configuration; see Chapter 27). However, the peripheral anterior chamber depth is always shallow.
Figure 24-1. Convex iris and narrow angle in a hyperopic patient. Only mid–trabecular meshwork was visible on gonioscopy, and the angle was judged to be potentially occludable.
Gray Atrophy of the Iris Stroma
After an attack of acute glaucoma, patchy gray atrophy of the iris stroma may develop, sometimes in just one quadrant or one small sector of the iris, and other times affecting the iris extensively. Such atrophy is not seen during the acute phase of an initial attack, becoming evident only after a few weeks. Acute angle-closure glaucoma is one of the few conditions that will produce this type of atrophy of the iris stroma. The other possible conditions that have been seen are cases of very high IOP after retinal detachment surgery and cases of hyphema with high IOP after contusion of the globe. If there is typical gray atrophy of the iris stroma, one can usually infer that the patient has experienced a past attack of acute glaucoma, especially when the characteristic atrophy is accompanied by glaukomflecken, as described next.
The appearance of iris atrophy caused by acute glaucoma is quite distinctive. Other forms of atrophy of the iris, as caused by uveitis, herpes zoster, or essential atrophy of the iris, differ sufficiently in appearance from that caused by acute glaucoma.
Figure 24-2. Numerous glaukomflecken were observed a prolonged attack of acute angle-closure glaucoma.
Glaukomflecken of Vogt
Glaukomflecken (Figure 24-2) consist of small white spots immediately in or beneath the anterior capsule of the lens in the pupillary zone, visibly demonstrating necrosis of lens epithelium associated with acutely high IOP. Glaukomflecken are sometimes confluent and form sheet-like opacities. These are a positive sign of a previous attack of acute glaucoma. Although not seen in all cases of acute angle-closure glaucoma, they are also not uncommon.
Glaukomflecken may occasionally be caused by an episode of very high IOP after a surgical procedure for retinal detachment, after hyphema, or from high IOP from blunt trauma to the globe. The opacities are permanent. As time passes and new lens fibers are laid down, the opacities gradually move deeper into the anterior cortex. This progressive movement to deeper layers happens more rapidly in younger people.
In most cases, the presence of glaukomflecken means there is high potential for another attack of acute angle closure unless the situation is recognized and addressed. Recognition of glaukomflecken may serve as a valuable clue, as illustrated by the following classic case from the era prior to laser iridotomy.
Case 24-1
A 35-year-old woman had a typical attack of acute angle-closure glaucoma in the left eye several months previously and had undergone a peripheral iridectomy in that eye. The referring ophthalmologist had never found an elevated IOP in the opposite eye. Corrected vision was 6/6 OD and 6/6 OS. The IOP was 17 mm Hg OD and 32 mm Hg OS. There was atrophy of the stroma of the iris in both eyes and glaukomflecken in both eyes. In the right eye, most of the angle appeared to be open though excessively narrow.
Although the patient had presented with left eye complaints, the appearance of iris stromal atrophy and glaukomflecken were considered evidence that the patient had experienced an attack of acute angle closure in the right eye at some point in the past. The patient at first denied any trouble with the right eye. However, on close questioning, she admitted that for the whole day after the iridectomy operation on the left eye, she had had severe pain in the right eye. It was concluded that she had experienced an attack of acute angle-closure glaucoma in the right eye that subsided spontaneously, leaving the tell-tale residue of atrophy of the iris stroma and glaukomflecken.
A peripheral iridectomy was advised for this eye. This was accomplished by her ophthalmologist and IOP remained normal without further treatment.
Cells in the Aqueous
In acute angle-closure glaucoma, cells in the aqueous are common. This may sometimes be confused with anterior uveitis. If the patient is seen early in the course of an attack of angle closure, one may see only a few cells or none at all. However, if the attack has been going on for hours or days, and especially if the eye shows considerable redness from vasodilation, the aqueous may contain many cells, as well as fibrin. In neglected cases, the formation of one or more posterior synechiae is not uncommon.
Considerable cellular debris may be seen on the back surface of the cornea, but typically, one does not see true keratic precipitates (KP). The presence of typical mutton-fat KPs are an indication of a pathologic process other than acute angle-closure glaucoma.
Corneal Edema
The corneal epithelium at first develops edema of a fine ground-glass character, giving the cornea a steamy appearance and causing the patient to see colored haloes around lights (Figure 24-3). Later in the course of a severe attack, at the stage where many cells appear in the aqueous and the eye becomes hyperemic, the whole thickness of the cornea may become swollen with wrinkling of the posterior surface. Wrinkling of the cornea is often prominent after IOP has dropped to normal levels, either spontaneously or as a result of treatment. As a rule, wrinkling of the posterior corneal surface is not seen when IOP is high.
Gonioscopy
If the cornea is sufficiently clear to permit examination of the angle, then extensive closure will be found during an attack. If the cornea is too cloudy to permit accurate gonioscopy in the affected eye, then gonioscopy of the fellow eye will usually reveal a convex iris and a very narrow angle. This finding in the contralateral eye is often very helpful in adding presumptive evidence for the diagnosis of acute angle closure.
Figure 24-3. Fine corneal haze (epithelial edema) that slightly obscures iris details, caused by sudden elevation of IOP. Patient observed colored haloes around lights.
If the fellow eye is found to have an anterior chamber that is distinctly less shallow and an iris that is less convex than the glaucomatous eye, then one should look at the patient’s glasses or refraction to see if the fellow eye is less hyperopic than the glaucomatous eye. If not, then one should suspect a secondary form of angle-closure glaucoma that is more often unilateral (see Chapter 41).
If the patient has been treated for acute elevation of pressure with systemic aqueous suppressants and/or osmotics, then this may potentially contribute to opening the angle of the fellow eye and make the findings in this eye equivocal. This medication effect should be taken into account when using the findings in the fellow eye to help establish the diagnosis (see Chapter 23).
Intraocular Pressure
In the midst of an attack of acute angle closure, one may find an IOP of 40 to 100 mm Hg. However, shortly after spontaneous recovery from an attack, IOP may temporarily become subnormal or lower than the fellow eye because of temporary dysfunction of the ciliary body and reduced aqueous production.
SPONTANEOUS RECOVERY AND MISDIAGNOSIS
The following 2 circumstances demonstrate a case where findings after spontaneous recovery from an acute angle-closure attack might lead to the wrong diagnosis.
Circumstance 1
The patient presents a day or two after an episode of pain and vision loss. He reports a history gradual onset of pain and blurred vision in one eye. Within an hour after the onset of symptoms, the pain and decreased vision became worse. He took some aspirin and went to bed. Overnight, the symptoms became less severe. The vision was much improved though still a little blurred, and there was no longer any discomfort.
Examination reveals a slightly congested eye, or an eye that may be white and quiet. The pupil is somewhat dilated and reacts sluggishly. There are folds in the posterior surface of the cornea and cells in the aqueous. There may be one or more posterior synechiae. Glaukomflecken may or may not be present. IOP is lower than in the fellow eye. If the cornea is clear enough for gonioscopy, the angle can be seen to be extremely narrow or closed. The angle in the fellow eye is also found to be extremely narrow.
The finding of folds in the cornea and of cells in the aqueous along with posterior synechiae in conjunction with a normal or subnormal IOP may point the clinician toward a diagnosis of iritis. However, the history of a typically monocular disorder with acute onset, the dilation of the pupil, and the gonioscopic examination of the angle of the affected eye and of the fellow eye should lead to the correct diagnosis of spontaneous recovery from an attack of acute angle-closure glaucoma.
It is not at all uncommon in this type of case for the clinician to make a misdiagnosis of iritis and prescribe topical steroids and cycloplegics. In response, the IOP may remain normal, and the eye may promptly resolve its inflammatory appearance. Anterior chamber cells may disappear. Nevertheless, the patient may show up the next week or sometime thereafter with recurrence of an attack of typical acute angle-closure glaucoma.
Circumstance 2
The patient presents with a history of acute onset of pain and blurred vision 1 or more days previously, with partial recovery of vision and disappearance of pain. Examination reveals little or no congestion of the eye. There may be cells in the aqueous or folds in the cornea. IOP is normal or subnormal. Examination of the fundus reveals disc swelling and many retinal hemorrhages throughout the posterior pole. Vision is fairly good.
At first glance, one might consider a diagnosis of optic neuritis or venous occlusion, but the history of a very acute onset of symptoms, with pain and blurred vision, would be inconsistent with such a diagnosis. Also, the subsequent rapid visual recovery to near normal would not be consistent with occlusion of the central retinal vein or with optic neuritis. Gonioscopic examination reveals the most important clue—an extremely narrow angle with or without areas of closure. The angle in the fellow eye is also found to be extremely narrow.
Now the correct diagnosis is made. The patient has had spontaneous recovery from an attack of acute angle closure, resulting in temporary hypotony, swelling of the disc, and hemorrhages in the fundus. If the diagnosis was missed, one could expect a recurrence of acute angle closure a few weeks later with a very high IOP and all the characteristic findings.
The following case was related by Dr. Chandler. It represents an instance in which the diagnosis of acute angle-closure glaucoma was missed early on. Dr. Chandler wrote, “This case illustrates the fact that 40 years ago Dr. Chandler still had a lot to learn about glaucoma.”
Case 24-2
A 46-year-old woman, seen 40 years previously, gave a history of having developed iritis in the right eye while on a cruise and having been given atropine ointment. When she returned home, her local ophthalmologist continued this treatment. Finally, the eye became completely quiet and she was referred for consultation. Corrected vision was 6/5 in each eye. The media were clear. Discs were normal. Visual fields were full. The anterior chambers were shallow. The right pupil was 4 by 5 mm and displaced slightly temporally, and the left pupil was 3 mm, round, and central. Atrophy of the iris was noted temporally in the right eye. On slit-lamp examination, there were some whitish flecks that seemed to be just beneath the anterior lens capsule. IOP was not measured. Gonioscopy was not done in those days.
There was no further trouble until 8 years later, when she developed acute glaucoma in the same eye. After miotic treatment, an iridectomy was performed. Later, prophylactic iridectomy was performed on the opposite eye at the patient’s request. IOP remained normal thereafter in both eyes.
Here is a classic picture of an eye that had acute angle-closure glaucoma. The iritis was undoubtedly sequelae from acute angle-closure glaucoma, and the initial treatment by mydriasis, as sometimes occurs, broke the first attack.
DIFFERENTIAL DIAGNOSES
A number of disorders can produce symptoms and signs of acute angle-closure glaucoma (Table 24-1). Glaucomatocyclitic crisis, neovascular glaucoma, and glaucoma secondary to anterior uveitis must all be considered in the differential diagnosis.
In glaucomatocyclitic crisis, there may be an acute onset of blurring and haloes and often some pain, but the angle is always open during an attack. Usually, one or several KPs are seen.
In neovascular glaucoma associated with prior occlusion of the central retinal vein, or diabetic retinopathy, and various other ischemic conditions that lead to anterior segment neovascularization, pain may develop acutely with corneal edema. At first glance, this might be mistaken for angle-closure glaucoma. However, there is no great difficulty in diagnosis. If the slit lamp does not reveal rubeosis of the iris (Figure 24-4), gonioscopy may show characteristic neovascularization in the angle (Figure 24-5).
TABLE 24-1. DIFFERENTIAL DIAGNOSIS OF ACUTE ANGLE-CLOSURE GLAUCOMA
| Disorder | Comment |
| Primary open-angle glaucoma with narrow angle on gonioscopy | Regardless of how narrow the angle, if posterior trabecular meshwork is visible for 360 degrees using Goldmann or Koeppe gonioscopy in a patient with high IOP, diagnosis is usually open-angle glaucoma; however, laser iridotomy may still be required in either case in order to prevent future angle closure. |
| Neovascular glaucoma | Iris and angle neovascularization may not be apparent with high IOP or corneal edema, requiring reexamination after IOP has been reduced; topical glycerin useful; angle of fellow eye usually open. |
| Uveitis | Anterior chamber inflammation may be present in both disorders with or without elevated IOP, but true keratic precipitates are not seen in angle closure; angle of affected and fellow eye are usually open by gonioscopy in uveitis, though focal peripheral anterior synechiae may be present; glaucomatocyclitic crisis most likely to confuse clinician. |
| Nanophthalmos | Patients with nanophthalmos have high hyperopia and short axial length (≤ 20 mm) bilaterally. |
| Secondary angle-closure glaucoma caused by panretinal photocoagulation (acute uveal effusion) | Complete ocular history and examination will often help identify patients with secondary angle closure; fellow eye may also be narrow in patients with malignant glaucoma and those status post-vitreoretinal buckling surgery; B-scan to rule out posterior segment pathology is indicated in all cases where there is a poor view of the fundus and incisional surgery is being contemplated. |
| Central retinal vein occlusion (acute uveal effusion) | |
| Medication induced (eg, sulfonamide allergy) | |
| Malignant glaucoma | |
| Post-vitreoretinal surgery | |
| Posterior segment tumors |
Secondary glaucoma due to iritis or uveitis should likewise present no great difficulty in diagnosis. For one thing, the pupil is never dilated. Generally, it is constricted or irregularly shaped from posterior synechiae. Examination of the angle sheds further light on the situation. In primary angle-closure glaucoma, the angle is closed either by apposition or by synechiae. In anterior uveitis, the angle is typically open. Nevertheless, prolonged anterior uveitis may be accompanied by eventual peripheral anterior synechiae (PAS) formation.
TREATMENT
Medical therapy is usually applied prior to laser iridotomy in order to decrease IOP and improve the clarity of the media for the laser procedure (Table 24-2). Sometimes, pupillary block can be broken mechanically by vigorous indentation gonioscopy and opening a segment of the angle. Similar indentation may be accomplished by applying pressure against the cornea with the blunt side of a muscle hook.1 In any case, laser iridotomy with or without laser gonioplasty should be performed promptly.
Medical Treatment
In the present era of ophthalmology, yttrium-aluminum-garnet (YAG), argon, or diode lasers are usually readily available. If the media is clear, one should proceed with laser iridotomy to break the attack. In the absence of immediate access to an appropriate laser, the following sequence of medical therapy can be used to try to break an attack of acute angle-closure glaucoma. Nevertheless, all efforts should be made to obtain access to a laser for definitive treatment, even as medical treatment is initiated.
No matter how obviously firm the eye is to palpation, IOP should be accurately measured with a tonometer in order to provide an objective point of reference. In this way, IOP can later be used in the course of treatment to determine whether the condition has changed either for the better or for the worse.
Figure 24-4. Neovascularization of the iris. Note the fine lacy vessels present at the pupillary margin.
Figure 24-5. Neovascularization of the angle. Note arborization of vessels. Glaucoma can be present with the angle still open at this stage before synechial formation occurs.
TABLE 24-2. OVERALL TREATMENT STRATEGY FOR ACUTE ANGLE-CLOSURE GLAUCOMA
| Treatment | Comment |
| Examination of both eyes (including gonioscopy of fellow eye) prior to treatment | Aqueous suppressants and osmotics alone can dramatically deepen the anterior chamber and widen the angle of both eyes, potentially confounding and delaying definitive treatment of the occludable fellow eye. |
| Indentation gonioscopy with a small-diameter goniolens or by central corneal indentation with a cotton swab or muscle hook | Sometimes, an attack of acute angle closure can be broken by central corneal compression, which deepens the angle and can break pupillary block. |
| Medical treatment (see Table 24-3) | Usually, it is best to reduce IOP prior to laser iridotomy; this allows corneal clearing, reduces patient discomfort, and gives time for the pupil to decrease in size, making laser treatment technically easier. |
| Laser iridotomy | Nd:YAG is preferred for light-colored irides (5 to 7 mJ, 1 to 2 bursts per pulse); for dark brown irides, a chipping technique with short-pulse argon laser treatment followed by Nd:YAG is recommended (see Chapter 55). |
| Peripheral laser gonioplasty | To open synechially closed angle remaining after laser iridotomy or in some cases to break an attack of angle closure (see Chapter 57). |
| Surgical iridectomy | In some cases, glaucoma is not controlled after laser iridotomy, or it is not possible to perform laser iridotomy; in these instances, multiple surgical options may be considered (see text). |
| Anterior chamber deepening | |
| Trabeculectomy |
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