A rare case of bilateral malignant glaucoma after cataract surgery with capsular tension ring implantation: a case report

Abstract

Background

Bilateral malignant glaucoma induced by a capsular tension ring associated with ring-shaped cysts of the ciliary body post-cataract surgery is rare. Herein, we present a case to highlight the possibility of capsular tension ring-induced malignant glaucoma.

Case presentation

A 59-year-old woman underwent phacoemulsification combined with capsular tension ring implantation for cataracts and zonular fibre laxity in both eyes. Upon admission, annular ciliary masses were detected in both eyes using ultrasound biomicroscopy. Two months post-surgery, the patient experienced vision deterioration, high intraocular pressure, and an axial shallowing anterior chamber in the right eye, and responded poorly to traditional anti-glaucoma medication. Ten days later, similar symptoms appeared in the left eye. Ultrasound biomicroscopy detected contact between the ciliary body and the capsular tension ring. Subsequently, malignant glaucoma was diagnosed. Anterior and posterior capsulotomies performed peripheral to intraocular lens optics using neodymium: YAG laser restored communication and alleviated the symptoms. A one-year follow-up revealed stable intraocular pressure and anterior chamber in both eyes.

Conclusions

This is the first case report of bilateral malignant glaucoma after cataract surgery induced by capsular tension ring, which is associated with bilateral ring-shaped cysts of the ciliary body. Blockage between the ciliary body and capsular tension ring was confirmed using ultrasound biomicroscopy.

Background

Malignant glaucoma (MG), first described by von Graefe in 1869, is a rare and refractory form of glaucoma that typically occurs after anti-glaucoma surgery in patients with a history of angle-closure glaucoma [1]. MG can also be induced by other ocular surgeries, such as cataract surgery, or by laser iridotomy, the use of miotic agents, and can even occur idiopathically [2,3,4,5]. Without timely and effective treatment, MG can have disastrous consequences, resulting in blindness [6, 7].

Herein, for the first time, we present a rare case of bilateral MG after cataract surgery with capsular tension ring (CTR) implantation, where the patient exhibited circumferential ring-shaped cysts of the ciliary body in both eyes. Further, we demonstrate the mechanism by which CTR induces MG.

Case presentation

A 59-year-old woman with blurred vision in both eyes underwent cataract surgery. The patient had no history of eye injuries or visual disturbances in her youth, no significant past medical history, and no family history of glaucoma or pathological myopia.

Preoperative manifest refraction was − 8.00 sph with 20/100 visual acuity in the right eye (OD) and − 7.75 sph with 20/100 visual acuity in the left eye (OS). While the IOL-Master 700 (Carl Zeiss AG, Oberkochen, Germany) showed normal axial length, 22.09 mm and 22.28 mm of the OD and OS, respectively. Slit-lamp biomicroscopy revealed a shallow anterior chamber, convex bowing of the iris, and lens opacity. The anterior depths were 1.70 mm and 1.84 mm in the OD and OS, respectively, and the sagittal lens diameters were 6.50 mm and 6.08 mm in the OD and OS, respectively. Intraocular pressure (IOP) measured using a non-contact tonometer was 17 mmHg and 12 mmHg in the OD and OS, respectively. Fundus examination was unremarkable, without mydriasis. The ocular ultrasound B-scan did not reveal any abnormalities in the posterior segments of both eyes (Fig. 1). Ultrasound biomicroscopy (UBM) (SW3200 Shanghai, China) revealed circumferential ciliary masses. The masses were homogeneous, almost identical on all meridians, and lacked narrower regions on circumferential scans of both eyes, suggesting monocystic masses (Fig. 2).

Figure Legends.

Fig. 1

Pre-surgery color picture of anterior segment showed both eyes had shallow anterior chamber and convex bowing of the iris. Wide-field fundus photography and B scan were unremarkable. IOLMaster 700 showed normal axial length, shallow anterior chamber, and abnormality of the lens thickness in both eyes

Fig. 2

Pre-surgery images of ultrasound biomicroscopy. a, The right eye was observed using ultrasound biomicroscopy (UBM) on different meridians from the 12 o’clock position in a clockwise direction and the circumferential scan. b, UBM images of the left eye

The patient underwent uneventful phacoemulsification in both eyes on two consecutive days. The AT LISA 809 intraocular lens (IOL) (Carl Zeiss AG) was implanted in the capsular bag by an experienced ophthalmologist. During surgery, loosening of the zonular fibres was detected in both eyes, and a CTR (Eyebright CTR1210, 12.0 mm in non-compressed diameters China) was implanted.

The day after surgery, the uncorrected visual acuity was 20/30 in the OD and 20/30 in the OS. The right eye had a myopic shift. The refraction error was − 1.50 sph in the right eye and + 1.50 sph in the left eye. IOP was 19.0 mmHg and 15.0 mmHg in the OD and OS, respectively, with a normal anterior chamber depth in both eyes. The anterior chamber of the right eye was subtly shallower compared to the OS. Postoperative anti-inflammatory medications were routinely administered (Tobradex eye drops were used for three weeks, three times a day and decrement once a week). One week post-surgery, routine checks were unremarkable. Owing to COVID-19, the patient did not undergo a routine check one month post-surgery.

Approximately two months post-surgery, the patient reported deteriorating vision in her OD but no redness, pain, headache, or nausea. An ocular examination of the OD showed that the uncorrected visual acuity had dropped to 20/60, and the IOP was 43 mmHg using a non-contact tonometer. No conjunctival congestion or corneal oedema was observed. The pupillary reflex was normal, and the anterior chamber was subtly shallower compared to the OS. A posterior capsular opacity was detected after mydriasis. The patient’s OS was normal. No optometry examination was conducted at that time.

Blurred vision was attributed to posterior capsular opacification, and elevated IOP was considered due to inflammation of the trabecular meshwork. Posterior capsulotomy was performed, and steroid eye drops (Tobradex four times a day) were administered; intensive anti-glaucoma therapy, including 20% mannitol, was also initiated. Despite these measures, IOP continued to rise, accompanied by a further decrease in the anterior chamber depth. UBM revealed the forward movement of the iris–lens diaphragm, with the CTR in direct contact with the ciliary mass (Fig. 3a). The diagnosis of malignant glaucoma was considered. To establish humoral communication between the anterior and posterior chambers and the vitreous cavity, peripheral iridozonulohyaloidotomy using neodymium: YAG was attempted but failed. The IOP peaked at 40mmHg. Cycloplegia with atropine 1.0% eye drops was prescribed. Subsequently, anterior and posterior capsulotomies peripheral to the IOL optics were performed using a neodymium: YAG laser, which successfully deepened the anterior chamber, gradually reducing the IOP to 17mmHg. The uncorrected visual acuity was 20/40 in the OD and 20/30 in the OS. The refraction error was − 0.25 sph in the right eye and + 2.00 sph in the left eye.

Fig. 3

a, Two days after posterior capsulotomy, ultrasound biomicroscopy (UBM) showed shallowing of the AC and angle closure in the right eye, the iris–lens diaphragm moved forward, and capsular tension ring (CTR) contacted the ciliary body directly. b, UBM taken on the day of onset showed shallowing of the AC and angle narrow in the left eye, anterior rotation of the ciliary body, and contact between the ciliary body and the CTR. Yellow arrow indicates the acoustic shadow of the CTR. AC = anterior chamber

Approximately 10 days post-onset of symptoms in the OD, the IOP in the OS progressively increased to 29mmHg, accompanied by the shallowing of the anterior chamber depth, which decreased from 4.49 to 2.44 mm. The OS experienced a -1.00 sph myopic shift. Similar anatomical structures were observed in both eyes, and UBM confirmed contact between the CTR and the ciliary body. The CTR-bag lens was pushed forward with anterior rotation of the ciliary body (Fig. 3b), suggesting aqueous misdirection. Cycloplegics were administered, and posterior and anterior capsulotomies were performed on the OS, normalizing the IOP (12mmHg) and anterior chamber depth.

Ten days later, a routine examination revealed 20/30 visual acuity in both eyes, with normal IOP and anterior chamber depth. The refraction was − 1.00 sph in the right eye and + 2.00 sph in the left eye and kept stable. UBM (AVISO, France) demonstrated patent communications (Fig. 4). After more than one year of follow-up, the visual acuity was 20/30, and the anterior chamber depth and IOP remained stable without medication in both eyes.

Fig. 4

Ultrasound biomicroscopy (UBM) images more than one year after laser treatment showed a patent communication (yellow star) from the posterior space of the lens to the posterior chamber in right eye and capsular tension ring (CTR) still contacting the ciliary body. The right eye had PAS at the position of the communication. In the left eye there was a patent communication between the ciliary body and CTR (yellow arrow). PAS = peripheral anterior synechia

Discussion and conclusions

Malignant glaucoma is an intractable form of secondary angle-closure glaucoma that is typically unresponsive to routine anti-glaucoma medication. MG encompasses various clinical situations, exhibiting extremely high IOP and a visibly shallow anterior chamber, peripherally and centrally, with anterior displacement of the iris–lens diaphragm.

Patients with shallow anterior chambers, short axial lengths, and small eyes are at high risk for developing MG. Aqueous misdirection is believed to cause symptoms associated with the specific anatomy of the ciliary body, lens, and anterior hyaloid face. The lens–ciliary body block or hyaloid–ciliary body block results in aqueous misdirection, causing fluid to become trapped in the vitreous cavity. This entrapment pushes the iris–lens diagram forward, effectively closing the angle where fluid usually drains from the eye and increasing the IOP. This creates a vicious circle. Terms such as aqueous misdirection, ciliary block glaucoma, ciliolenticular glaucoma, and ciliovitreal block glaucoma describe this phenomenon [8].

UBM is the gold standard for anterior segment examination, providing high-resolution in vivo images of the iris, ciliary body, lens, and their positional relationships [9]. UBM also aids in ruling out pathological changes such as suprachoroidal haemorrhage and choroidal effusion, facilitating accurate diagnosis and differentiation of MG [10, 11]. In our case, annular ciliary body masses were observed bilaterally. These were homogeneous cystic masses, with internal reflectivity slightly higher than the anterior and posterior chambers and devoid of solid components or pigments. Ciliary melanoma was ruled out. The ciliary body masses remained stable during one year of follow-up. Although no histopathological results were obtained, ciliary body cysts were considered. They were almost identical on all meridians and lacked narrower regions on circumferential scans in both eyes. Therefore, we considered these cysts to be monocystic. Ciliary body masses were considered to cause laxity of the lens zonular fibres, resulting in maximum accommodation and increased lenticular curvature, which, compounded by vitreous pressure, led to forward movement of the lens–iris diaphragm. Therefore, the patient had myopia of lenticular origin, and ocular examination revealed normal axial length, crowded anterior chamber, and increased lens thickness. Complete bilateral ring-shaped cysts of the ciliary body are very rare. To our knowledge, only one case of bilateral ring-shaped cysts has been reported in the literature [12]. This case involved a 33-year-old woman who spontaneously developed MG in her OS, which was resolved by lensectomy combined with vitrectomy. The patient’s OD remained stable for at least one year.

In our case, MG occurred two months post-phacoemulsification combined with CTR implantation in both eyes. CTR has been widely used in complicated cataract surgeries with zonular dehiscence or weakness to reinforce zonular fibres and stabilise the capsules. Corneal oedema and transiently elevated IOP were the main postoperative complications [13]. Bochmann and Strümer et al. presented a series of seven cases in which chronic and intermittent angle closure was caused by an anteriorly dislocated capsular bag-CTR-IOL complex in patients with pseudoexfoliation syndrome [14]. Another case highlighted recurrent intraocular hypertension due to CTR exposure to the ciliary body, triggering increased aqueous humour secretion [15]. Only one case of CTR-induced unilateral MG has been reported in the literature [16]. The patient was diagnosed with MG after trabeculectomy in her OD. She had a history of phacoemulsification and CTR implantation due to cataracts and lens zonular laxity, experiencing postoperative high IOP and a shallow anterior chamber, refractive to anti-glaucoma medications for several months. Contact between CTR and the ciliary body was considered the underlying mechanism. Symptoms were relieved with low-dose laser cyclophotocoagulation. Our case was bilateral; this marked the first reported instance of bilateral MG associated with ring-shaped cysts of the ciliary body following combined phacoemulsification and CTR implantation. UBM confirmed multiple locations of direct contact between CTR and the ciliary body. The ciliary body and capsular bag-CTR-IOL complex formed a barrier, disrupting humoral communication. Increased aqueous humour secretion caused by CTR stimulation of the ciliary body may also contribute to elevated IOP.

To effectively resolve MG, breaking the vicious circle and restoring proper aqueous flow is crucial [17]. Varma et al. recommended a stepwise treatment approach, starting with medical therapy, followed by laser treatment, and resorting to surgery as a last option [3]. Their report demonstrated that medical therapy alone was inadequate in most cases as it did not address the underlying mechanism. Laser iridozonulohyaloidotomy or laser capsulotomy and anterior hyaloidotomy have been accepted as less aggressive and more efficient interventions for relieving the condition. A new variant of irido-zonulo-hyaloid-vitrectomy was proposed by Tosi et al. for the management of refractory pseudophakic MG and it turned out to be safe and effective [18]. By restoring communication between the anterior chamber and the vitreous cavity, the block is broken, the lens–iris diaphragm returns to the normal position, closed angles reopen, and the IOP decreases. We tried to perform peripheral iridozonulohyaloidotomy using neodymium: YAG. An iridotomy was created successfully, but the zonules and anterior hyaloid could not be reached. UMB showed that in our case, the exact mechanism of MG was a block between the ciliary body and the CTR. Given the difficulty of CTR removal, we performed laser capsulotomy. Both anterior and posterior capsulotomies peripheral to the IOL optics were performed using neodymium: YAG laser, and patent communications were restored successfully in both eyes, confirmed by UBM. The relief of symptoms after laser treatment also validated our hypothesis.

Here, we describe a rare case of complete bilateral ring-shaped cysts in the ciliary body. The development of MG in both eyes after phacoemulsification combined with CTR implantation makes it more complicated. UBM is irreplaceable in diagnosing and elucidating the underlying anatomical mechanisms of MG. Given the widespread use of CTR in complicated cataract surgery, we suggest considering the possibility of CTR-induced MG.