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Long-term therapeutic efficacy of phacoemulsification with intraocular lens implantation in patients with phacomorphic glaucoma

Lee, Soo Jung MD, PhD; Lee, Chang Kyu MD; Kim, Wan-Soo MD, PhD

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Journal of Cataract & Refractive Surgery: May 2010 - Volume 36 - Issue 5 - p 783-789
doi: 10.1016/j.jcrs.2009.11.023
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Abstract

Phacomorphic glaucoma is usually caused by lens swelling in eyes with mature or hypermature cataract. When the lens swells, angle-closure glaucoma with pupillary block occurs in the acute phase; in the late phase, it can occur even without pupillary block as a result of forward movement of the peripheral iris.1 Causes of phacomorphic glaucoma include traumatic cataract, a rapidly progressive senile cataract, a lack of diagnosis and thus delayed cataract surgery, and swelling of a cataractous lens. Phacomorphic glaucoma is more common in the Asian population than in the white population; the incidence appears to be similar in men and women, although precise data are lacking.2

Laser iridotomy, extracapsular cataract extraction (ECCE), intracapsular cataract extraction (ICCE), and cyclodialysis have been used to treat phacomorphic glaucoma.3–7 In many cases, severe corneal edema, intraocular inflammation, and efflux of hydrated cortex when the capsule is punctured obscure the operative view in eyes with phacomorphic glaucoma. Also, the absence of the red reflex makes localization of the clear anterior lens capsule difficult. In these eyes, creating a continuous curvilinear capsulorhexis (CCC) and performing phacoemulsification can be challenging because of high pressure in the anterior chamber and posterior vitreous, a shallow anterior chamber, frequent radial tears of the anterior capsule, and posterior capsule rupture.8 The CCC success rate has increased recently with the use of dim operative lighting, high-power operative microscopes, endoilluminators, ophthalmic viscosurgical devices (OVDs), aspiration of the hydrated cortex, and capsule staining with dye. These techniques have increased the safety of phacoemulsification and led to a low incidence of intraocular lens (IOL) decentration.

Development of the soft-shell technique to protect corneal endothelial cells made it possible to perform phacoemulsification to remove the swollen lens. However, there are few reports of the efficacy and surgical outcomes of phacoemulsification in these eyes.9–13 Thus, we evaluated the long-term therapeutic efficacy of phacoemulsification with IOL implantation in patients with phacomorphic glaucoma.

PATIENTS AND METHODS

This retrospective study reviewed the charts of patients who had phacoemulsification and IOL implantation for treatment of phacomorphic glaucoma from November 1997 to December 2003 with a minimum follow-up time of 48 months. Patients lost to follow-up or with a history of other intraocular surgery were excluded.

Preoperative Evaluation

Preoperative evaluation included slitlamp examination and gonioscopy with Goldmann 3-mirror lenses (Volk Optical, Inc.). Visual acuity and corneal curvature were measured. Intraocular pressure (IOP) was assessed by noncontact tonometry (TX-10 tonometer, Canon, Inc.). A B-scan was performed to examine the vitreous body and retina in patients with severe corneal opacity or cataract. The axial length (AL), lens thickness, and anterior chamber depth (ACD) were measured by A-scan.

Phacomorphic glaucoma was diagnosed when the following 3 criteria were fulfilled: (1) high IOP; (2) a swollen cataractous lens compared with the lens in the stable fellow eye on slitlamp examination and a very shallow anterior chamber caused by forward lens movement; (3) lens thickness of 5.0 mm or greater and an ACD of 2.0 mm or less on A-scan. An intravenous mannitol (20%, w/v) injection and oral acetazolamide were administered to all patients to reduce IOP and severe corneal edema before surgery. One of the following was also given for the same reasons: a β-blocker (0.5% w/v), a selective α2-agonist, or a carbonic anhydrase inhibitor (as eyedrops).

Surgical Technique

The same surgeon (W.S.K.) performed all surgeries. The temporal conjunctiva was incised and a 3.8 mm wide scleral incision created 1.5 mm from the limbus. An entrance to the anterior chamber was made using crescent and slit blades. Next, a highly dispersive OVD was injected into the anterior chamber in an amount sufficient to prevent release of lens materials during CCC. To permit observation of anterior lens capsules in eyes with mature or hypermature cataract, the capsules were stained with trypan blue or an endoilluminator was used. A CCC was created with a 26-gauge bent needle and a capsule forceps. The CCC was 1.0 mm smaller than the IOL optic diameter. To obtain a clear operative field, highly cohesive OVD was injected into the anterior chamber and the hydrated cortex aspirated with a syringe to the extent possible. The lens nucleus and cortex were removed by phacoemulsification, irrigation, and aspiration, after which a foldable acrylic IOL was implanted in the capsular bag A primary posterior CCC was performed in cases in which good postoperative visual acuity would not be achieved because of significant posterior capsule opacity.

Postoperative Protocol

Postoperatively, tobramycin eyedrops, flurbiprofen sodium, and prednisolone acetate 1% were administered for 3 months to prevent infection and control intraocular inflammation.

Visual acuity and IOP were measured and a slitlamp examination was performed at each postoperative visit. Gonioscopy and ACD A-scan measurements were performed 1 month postoperatively.

Statistical Analysis

Comparisons of visual acuity, IOP, ACD, and lens thickness between preoperatively and postoperatively were performed using SPSS software for Windows (version 10.0, SPSS, Inc.); the changes in the values were analyzed by the paired t test. The relationship between postoperative vision and the duration of corneal edema was evaluated using the Spearman correlation coefficient. A P value less than 0.05 was considered statistically significant.

RESULTS

The study evaluated 26 eyes of 26 patients. The mean age of the 13 men and 13 women was 68.8 years ± 8.8 (range 40 to 80 years). Twenty-two patients were 65 years or older (mean 71.7 years) and 1 patient each was aged 63 years, 55 years, 52 years, and 40 years. The mean follow-up was 54.8 months (range 48.2 to 59.0 months). Table 1 shows the additional operative procedures and postoperative medication.

Table 1
Table 1:
Additional operative procedures and postoperative medication.

The patients had glaucoma-related symptoms (eg, ocular pain, headache, nausea, vomiting) for 1 to 15 days before presentation. The mean duration of preoperative glaucomatous symptoms was 5.9 ± 3.9 days.

Table 2 shows the clinical characteristics of the patients. Most cataracts were mature or hypermature, although some were of moderate grade. Although preoperative gonioscopy was performed, the exact condition of the anterior chamber angle could not be determined because of severe corneal edema and opacities; there were no specific findings in the stable fellow eyes.

Table 2
Table 2:
Clinical characteristics of phacomorphic glaucoma patients.

Preoperative A-scan showed a mean lens thickness of 5.6 ± 0.2 mm (range 5.1 to 6.0 mm), a mean AL of 22.3 ± 0.6 mm, a mean ACD of 1.5 ± 0.3 mm, and a mean ratio of lens thickness to AL (ie, lens thickness/AL) of 0.25 ± 0.01, indicating shallow anterior chambers (Figure 1). Table 3 shows the values of these parameters by individual patient.

Figure 1
Figure 1:
Example of the severe lens swelling present in all eyes before surgery.
Table 3
Table 3:
Biometric findings in phacomorphic glaucoma patients.

The mean IOP was 49.0 ± 10.4 mm Hg (range 31 to 70 mm Hg) preoperatively and 15.7 ± 3.0 mmHg 1 day postoperatively; the decrease was statistically significant (P<.0001). At 48 months, the mean IOP was 13.2 ± 2.8 mm Hg (range 8 to 20 mmHg); the decrease from preoperatively was 38.6 ± 10.4 mm Hg, which was statistically significant (P<.0001) (Figure 2).

Figure 2
Figure 2:
Changes in IOP over time (IOP = intraocular pressure).

Preoperatively, the corrected distance visual acuity (CDVA) was 20/500 in 2 eyes (7.7%), 20/50 in 1 eye, and 20/100 in 2 eyes (11.5%), hand motion in 15 eyes (57.7%), light perception in 5 eyes (19.2%), and no light perception (NLP) in 1 eye (3.8%). By 48 months postoperatively, the CDVA had improved significantly in 25 eyes (96.2%) (P<.0001). The CDVA was 20/50 or better in 16 eyes (61.5%), 20/60 to 20/100 in 7 eyes (26.9%), 20/200 in 1 eye (3.8%) and counting fingers at 50 cm in 1 eye (3.8%). In the 1 eye (3.8%) with a preoperative CDVA of NLP, there was no improvement after surgery.

At 48 months, the CDVA was 20/20 to 20/100 in the 22 eyes (84.6%) that had glaucoma symptoms for fewer than 8 days preoperatively and 20/100 to NLP in 4 eyes (15.4%) with symptoms for more than 12 days (Table 4 and Figure 3).

Table 4
Table 4:
Change in CDVA over time.
Figure 3
Figure 3:
The CDVA 48 months after surgery by duration of preoperative glaucoma symptoms (CDVA = corrected distance visual acuity).

The mean time to resolution of Descemet folding on slitlamp examination was 6.2 ± 3.8 days postoperatively. There was no statistically significant correlation between the duration of corneal edema and final CDVA (P = .756).

Vitreous prolapse and hyphema occurred during pupilloplasty in 1 eye with previous traumatic zonular dialysis and iris distortion; the IOP in this eye was consistently 18 to 25 mm Hg during the first postoperative month. A combination of dorzolamide and a β-blocker was administered for 5 weeks and then discontinued because the IOP returned to normal.

During surgery, a 3 o'clock radial tear occurred in 1 eye just before CCC. One patient required continuous glaucoma medication after surgery; gonioscopy showed the patient had peripheral anterior synechias (PAS) at 3 o'clock immediately after surgery (Figures 4 and 5).

Figure 4
Figure 4:
In patient 7, the IOL was inserted in the bag. Iris atrophy and PAS from 3 to 6 o'clock were observed after surgery.
Figure 5
Figure 5:
Example of a clear cornea and deep anterior chamber deep postoperatively.

DISCUSSION

Phacomorphic glaucoma caused by swollen cataracts develops from secondary peripheral angle closure by pupillary block or from acute closure of the anterior chamber angle by forward movement of the peripheral iris; it can occur even when there is no pupillary block.1 Relative pupillary block is often seen in eyes with a shallow anterior chamber, small corneal diameter, short posterior radius, and a lens thickened by aging; it is closely related to a high ration of lens thickness to AL.14,15

Lin et al.16 found that relative pupillary block was rare when the ACD was deeper than 2.7 mm. In their study, eyes with angle-closure glaucoma had a mean AL of 22.3 ± 0.8 mm, which was approximately 1.0 mm shorter than in normal eyes, and a mean ACD of 1.8 ± 0.2 mm, which was approximately 0.8 mm shallower than in normal eyes. The mean lens thickness was 4.9 ± 0.3 mm, thicker than the mean of 4.5 ± 0.3 mm in normal eyes. Qi17 found a lens thickness to AL ratio of more than 0.2 in eyes with angle-closure glaucoma, a finding that can be helpful in the diagnosis of angle-closure glaucoma.

In our study, preoperative A-scans showed a mean lens thickness of 5.6 ± 0.2 mm, indicating lens swelling, and a mean ACD of 1.5 ± 0.3 mm, which is extremely shallow and was the result of the lens swelling. The mean preoperative AL was 22.3 ± 0.6 mm, indicating that phacomorphic glaucoma was prevalent in hyperopic eyes, and the mean preoperative ratio of lens thickness to AL was 0.25 ± 0.01, indicating angle-closure glaucoma. After surgery, the mean ACD increased significantly to 2.6 ± 0.1 mm (P<.0001). The mean decrease in IOP from preoperatively to 48 months postoperatively was 33.2 ± 7.4 mm Hg (range 23 to 51 mm Hg).

Phacomorphic glaucoma should be distinguished from angle-closure glaucoma, in which the peripheral anterior chamber angle is shallow in both eyes. Therefore, the fellow eye should always be examined.

Conventional treatments for phacomorphic glaucoma include laser iridotomy, ECCE, ICCE, and cyclodialysis. Laser iridotomy can be performed after medical treatment with miotics, β-blockers, carbonic anhydrase inhibitors, hyperosmotic agents, and α-agonists when PAS are not extensive.3 However, laser iridotomy is not the preferred treatment for phacomorphic glaucoma because the angle closure can remain and the iridotomy site occluded by a subluxated lens or vitreous. Laser iridotomy is impossible in patients with severe corneal edema or very shallow anterior chambers associated with acute glaucoma attacks.

In the past, most surgeons considered ECCE or ICCE to be the preferred treatment because phacomorphic glaucoma occurred in patients with mature or hypermature cataract, 18,19 was usually accompanied by pseudoexfoliation syndrome and zonular dialysis,18,19 and hampered visibility of the operative field because of corneal edema and intraocular inflammation. However, cataract extraction is associated with an increased risk for complications, such as repeated iris prolapse, anterior chamber collapse, vitreous loss, corneal endothelial injury, and postoperative fibrin formation in the anterior chamber. Chandler and Grant4 report that cataract extraction alone did not lower IOP for more than 2 years. Shields and Simmons5 found that the IOP decrease was mild after cataract extraction alone; the mean IOP decrease was 5 mm Hg (range 2 to 10 mm Hg). The authors suggested that the decrease might be attributable to PAS or trabecular injury. Shields and Simmons,5 Galin et al.,6 and Harrington7 developed a combination therapy of cataract extraction and cyclodialysis that lowered IOP by 15 to 29 mm Hg and afforded good IOP control in 90% to 95.3% of patients; 60% required no subsequent medical treatment to control IOP. Chandler and Manmenee20 suggest a mechanism in the decrease of IOP was that the cyclodialysis caused a decrease in aqueous production; fluorescein injected into the anterior chamber was located between the suprachoroid and sclera, indicating aqueous outflow from the chamber. However, cyclodialysis is often complicated by ocular hypotension and hyphema, and patients having aqueous filtering surgery, such as trabeculectomy, are at high risk for shallow or collapse of the anterior chamber. Therefore, neither trabeculectomy nor cyclodialysis to treat phacomorphic glaucoma is popular today.

Recently, phacoemulsification has been commonly used to treat phacomorphic glaucoma because the techniques and instruments have improved rapidly and the use of highly dispersive and cohesive OVDs make CCC creation easy, create less stress on the zonules and thus reduce the risk for IOL decentration, and reduce the liberation of milky lens material and its dispersion to the angle structure. In addition, the IOL is not in contact with uveal tissues, so pigment dispersion and inflammation are rare.9–12 Eyes with phacomorphic glaucoma have very shallow anterior chambers; therefore, we used highly dispersive OVDs to effectively maintain the anterior chambers during manipulation. We used a 26-gauge bent needle to remove the hydrated cortex to minimize dispersion of lens materials and to prevent radial tearing by relaxing the tension on the lens capsule. These procedures likely prevent intratrabecular occlusion by lenticular protein particles and phagocytes, leading to continuous and significant improvements in visual acuity and decreases in IOP.21

In our study, the decrease in IOP 1 day postoperatively and the improvement in visual acuity beginning at 1 week were significant. The likely reason for the relatively slower visual recovery is corneal edema that persisted for 1 week postoperatively. Visual acuity improved postoperatively in 25 eyes (96.2%); there was no improvement in 1 eye (3.8%) with a preoperative visual acuity of NLP. During their glaucoma attack, all patients were transferred to our hospital from distant locations; therefore, we could not evaluate endothelial cell density (ECD) before the attack, nor were there records from other clinics. The mean postoperative ECD was 1523.4 cell/mm2 (range 892.4 to 2132.9 cell/mm2). During the 48-month follow-up, 1 patient had a slow increase in IOP; however, the patient responded well to continued treatment with a combination of dorzolamide and a β-blocker. This patient had PAS immediately after surgery, the longest preoperative period of glaucoma (15 days), and the highest preoperative IOP. When glaucomatous symptoms persist for more than 7 days, extensive PAS can form and trabecular injury can occur. In these cases, cataract extraction induces a late, slow increase in IOP despite an initial IOP decrease.22 When surgery is performed more than 5 days after onset of the initial glaucoma symptoms, the postoperative visual prognosis is poor.23 In this study, patients with a relatively short duration (<8 days) of preoperative glaucoma symptoms had more postoperative visual improvement than those with a longer duration (>12 days) of glaucoma. Although we did not evaluate them in this study, various factors, such as corneal endothelial cell damage, decreases in cell number after acute glaucoma attack, spherical aberration caused by mid-dilated or fixed pupils due to pupillary constrictor muscle paralysis, and optic atrophy, are thought to act synergistically to affect postoperative visual outcomes.

In conclusion, our results indicate that combined phacoemulsification and IOL implantation is a safe and effective procedure that offers long-term visual improvement and IOP control in patients with phacomorphic glaucoma. In our study, the procedure was associated with a lower complication rate than other surgical procedures.

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