Abstract
Purpose:
To report the clinical profile and treatment outcomes of malignant glaucoma and the efficacy of pars plana vitrectomy-hyaloidotomy-zonulectomy and iridectomy in Indian eyes.
Design:
Retrospective observational study.
Methods:
The study was a retrospective chart review. Medical records of patients diagnosed with malignant glaucoma between December 2018 and August 2022 were reviewed. Patients with the diagnosis of malignant glaucoma and those who underwent pars plana vitrectomy-hyaloidotomy-zonulectomy-iridectomy were included in the study. Patients with less than 3 months of follow-up were excluded from the study. Data collected included demographic data, primary ocular procedure, best-corrected visual acuity in logMAR, and lens status. The data also included intraocular pressure and number of antiglaucoma medications used at the time of presentation and during follow-ups.
Results:
The final analysis included 36 eyes of 30 patients. There was a statistically significant reduction of intraocular pressure at each visit (P value = 0.001) and in the number of antiglaucoma medications (P value < 0.001). A total of 29 eyes had a follow-up of 6 months, 19 eyes (65.5%) had a complete success, and 10 eyes (34.4%) had qualified success at the end of 6 months.
Conclusion:
Pars plana vitrectomy-hyaloidotomy-zonulectomy-iridectomy surgery has favorable outcomes in eyes with malignant glaucoma.
Keywords: Aqueous misdirection syndrome, malignant glaucoma, pars plana vitrectomy-hyaloidotomy-zonulectomy-iridectomy
Malignant glaucoma or aqueous misdirection syndrome is characterized by uniform shallowing/flattening of the anterior chamber in the presence of patent iridotomy or iridectomy. Malignant glaucoma can occur following various surgical procedures like glaucoma filtration surgeries, cataract surgeries, laser iridotomy, laser cyclophotocoagulation, etc.[1] Conditions like choroidal hemorrhage, choroidal effusion, and pupillary block should be ruled out by an ultrasound bio-microscopy.
The treatment of malignant glaucoma is aimed at relieving the aqueous misdirection. The first line management of aqueous misdirection is mainly medical, in the form of cycloplegics like atropine eye ointment 1% (to push the iris lens diaphragm posteriorly), topical and systemic antiglaucoma medications, and steroids. Even though medical therapy alone can be successful in about 50% of the cases, there is a high rate of relapse.[2] Neodymium: yttrium aluminum garnet (Nd-YAG) laser can be used to disrupt the anterior hyaloid face to create communication between the anterior vitreous and anterior chamber in the case of pseudophakic and aphakic malignant glaucoma.[3] Recently, pars plana vitrectomy in combination with zonulectomy and hyaloidotomy has been introduced for surgical management of malignant glaucoma which claims to have promising outcomes. This study aims to report the clinical profile and treatment outcomes of malignant glaucoma and the efficacy of pars plana vitrectomy-hyaloidotomy-zonulectomy and iridectomy in Indian eyes at a tertiary care center.
Methods
This study was conducted at a tertiary ophthalmic care center in South India. Institutional review board approval for a retrospective study analysis was obtained. Medical records of patients diagnosed with malignant glaucoma between December 2018 and August 2022 were retrospectively reviewed. Malignant glaucoma was defined as normal or elevated intraocular pressure with axial shallowing of the anterior chamber in the presence of a patent iridotomy and absence of choroidal detachment. The patients with the diagnosis of malignant glaucoma, who underwent pars plana vitrectomy-hyaloidotomy-zonulectomy iridectomy, were included in the study. Patients who underwent only medical therapy or those who had inadequate follow-up (less than 3 months) were excluded from the study.
Data was collected from electronic medical records, and it included age, sex, laterality, primary ocular procedure, primary diagnosis, best-corrected visual acuity in logMAR, and lens status. The data also included intraocular pressure, whether injection mannitol was given at the time of presentation, the number of antiglaucoma medications used at the time of presentation, and during follow-ups.
The treatment outcomes were described as anatomical success, complete success, qualified success, and failure. Anatomical success was defined as the deepening of the central anterior chamber on slit lamp biomicroscopic examination. Complete success was defined as deepening of the anterior chamber centrally with an IOP of less than or equal to 21 mmHg without antiglaucoma medications. Qualified success was defined as the deepening of the anterior chamber centrally with an IOP of less than or equal to 21 mmHg with antiglaucoma medications. Failure was defined as a flat anterior chamber and/or intraocular pressure of more than 21 mmHg with antiglaucoma medications on two consecutive visits or requiring a second procedure for the control of IOP.
All the surgeries were performed by retina surgeons. Surgical management included 23 or 25-gauge pars plana vitrectomy-hyaloidotomy-zonulectomy-iridectomy. A posterior-to-anterior route was followed. After core vitrectomy, anterior vitrectomy was performed to ensure adequate removal of the anterior hyaloid. With a vitrectomy cutter, zonulectomy and peripheral iridectomy were made creating a unicameral eye [Fig. 1].
Figure 1.
Steps of surgery. a – pars plana vitrectomy. b – Anterior vitrectomy. c – Zonulectomy and iridectomy
The demographic variables are presented with descriptive statistics. Results relating to continuous variables are expressed as mean and standard deviation. The differences between quantitative variables were analyzed using a paired t-test. Kaplan–Meier analysis survival probability plot was used to represent cumulative survival probabilities. Statistical analysis was performed by using SPSS version 25 (SPSS statistics for windows, version 25.0, Armonk, NY: IBM corp).
Results
During the study period, there were 49 eyes of 43 patients, which were diagnosed with malignant glaucoma. The final analysis included 36 eyes of 30 patients [Fig. 2]. Seventeen were females, and 13 were males. The mean age of the study population was 70 ± 10.7 years (range, 43–88 years). Out of 36 eyes, 19 eyes (52.77%) had uneventful cataract surgery, 11 eyes (30.55%) had primary angle closure glaucoma, two eyes (5.5%) had neovascular glaucoma, two eyes (5.5%) had pseudoexfoliation glaucoma, one eye (2.77%) had phacolytic glaucoma, and one eye (2.77%) underwent penetrating keratoplasty. The primary procedure of 16 patients (22 eyes) was performed in our hospital, and 14 patients (14 eyes) were performed in other hospitals and were referred to us for further management. Thirty-five eyes were pseudophakic with in-the-bag placement of the posterior chamber intraocular lens, and one was aphakic. Fourteen eyes had microcystic corneal edema, and four eyes had peripheral anterior synechiae at presentation. B-scan was performed in all the eyes, and none had a suprachoroidal hemorrhage or choroidal detachments, while three eyes had aqueous pockets on the B-scan. A total of 200 mL of 20% intravenous mannitol was given over 30 minutes in 17 patients at presentation and in 22 patients 30 minutes before the procedure.
Figure 2.
Flow chart for patient selection
The most common intraocular procedure preceding malignant glaucoma was cataract surgery (either sics + iol or phaco + iol, 67.8% eyes; 24 out of 36 eyes) followed by phaco-trabeculectomy (22.2%; 8 out of 36 eyes). The average duration between the primary procedure and the development of malignant glaucoma was 183.2 days (range, 1–1535 days). The average duration between the development of malignant glaucoma and the pars plana vitrectomy-hyaloidotomy-zonulectomy-iridectomy was 2.61 days (range, 0–19 days). Thirteen patients were operated on the same day of presentation. The mean logMAR visual acuity at presentation was 1.2 ± 0.886 (range, 0.00–2.50) and at the final follow-up was 0.67 ± 0.691 (range, 0.00–2.5). There was a statistically significant improvement in mean visual acuity post-procedure (P value = 0.001) [Table 1]. The mean intraocular pressure at presentation was 37.3 ± 11.1 (range, 12–68 mmHg), and the mean at the final follow-up was 13.8 ± 2.944 mmHg (range, 10–20 mmHg). There was a statistically significant reduction of IOP at each visit (P value = 0.001) [Table 2]. The mean number of topical antiglaucoma medications at the time of presentation was 2.64 ± 0.73. It was reduced to 0.38 ± 0.561 at the time of final follow-up, and the reduction was statistically significant at every follow-up visit (P value < 0.001) [Table 3]. The cycloplegic (atropine 1%) was continued for 1 month postoperatively. Out of 29 patients who came for a 6-month follow-up 19 patients were found to be not on any antiglaucoma medications.
Table 1.
Visual acuity in logMAR pre- and post-procedure
| BCVA | n | Mean | Std. deviation | P | ||||
|---|---|---|---|---|---|---|---|---|
| Pre-op | 36 | 1.20 | 0.886 | |||||
| Day 1 | 36 | 1.12 | 0.885 | 0.093 | ||||
| Month 1 | 36 | 0.91 | 0.856 | 0.001** | ||||
| Month 3 | 36 | 0.86 | 0.838 | 0.001** | ||||
| Month 6 | 29 | 0.67 | 0.691 | 0.001** |
**indicates statistically significant, Wilcoxon signed-rank test was used to find the P value
Table 2.
Intraocular pressure at pre-op and follow-up visits
| IOP | n | Mean | Std. deviation | P | ||||
|---|---|---|---|---|---|---|---|---|
| Pre-op | 36 | 37.39 | 11.093 | |||||
| Day 1 | 36 | 17.83 | 10.402 | 0.001** | ||||
| Month 1 | 36 | 15.92 | 7.330 | 0.001** | ||||
| Month 3 | 36 | 15.13 | 7.964 | 0.001** | ||||
| Month 6 | 29 | 13.79 | 2.944 | 0.001** |
**indicates statistically significant, Wilcoxon signed-rank test was used to find the P value
Table 3.
Number of antiglaucoma medications pre-op and follow-up visits
| Time Points | n | Mean | Std. deviation | P | ||||
|---|---|---|---|---|---|---|---|---|
| Pre-op | 36 | 2.64 | 0.723 | |||||
| Day 1 | 36 | 1.56 | 1.132 | 0.001** | ||||
| Month 1 | 36 | 0.97 | 0.941 | 0.001** | ||||
| Month 3 | 36 | 0.78 | 0.898 | 0.001** | ||||
| Month 6 | 29 | 0.38 | 0.561 | 0.001** |
**indicates statistically significant. Wilcoxon signed-rank test was used to find the P value
Thirty eyes did not show any postoperative complications, while three eyes had severe corneal edema which resolved in an average duration of 2.3 weeks, and another three eyes developed serous choroidal detachment which resolved in 1 month with medical management. Deepening of the central anterior chamber was observed in 35 eyes at the end of 3 months; thus, an anatomical success rate of 97.22% was achieved. Sixteen (44.4%) out of 36 eyes achieved complete success, while 17 (47.22%) eyes achieved qualified success at the end of 3 months. A total success of 91.6% was achieved at the end of 3 months. Three out of 36 eyes (8.3%) failed at the end of 3 months and two eyes underwent diode cyclophotocoagulation at an average of 4.32 months postoperatively. Twenty-nine eyes had a follow-up of 6 months; among them, 19 eyes (65.5%) had complete success, and 10 eyes (34.4%) had qualified success at the end of 6 months [Fig. 3].
Figure 3.
Kaplan–Meier survival analysis curve for qualified success and complete success
Discussion
Aqueous misdirection is a form of secondary angle closure with uniform shallowing of the anterior chamber.[4] The exact mechanism, resulting in aqueous misdirection, is not clearly understood. But it can be related to the abnormal anatomical relationship between the ciliary body, anterior hyaloid, lens, and the vitreous.[5] Medical treatment includes topical cycloplegics, antiglaucoma medications, oral carbonic anhydrase inhibitors, and the use of hyperosmotic agents like injection mannitol 20% intravenous solution. Although 50% of eyes respond favorably to medical therapy alone, the majority of these cases can have recurrence on cessation of the treatment.[6] Laser treatment in the form of laser capsulotomy with anterior hyaloidotomy to incise the thickened anterior hyaloid or cyclophotocoagulation to shrink the ciliary processes and thereby to break the ciliary block is attempted if medical treatment remains ineffective in pseudophakic or aphakic eyes.[7,8] The principle of surgical treatment of malignant glaucoma is to disrupt the anterior vitreous face or remove the vitreous and to establish communication between the anterior chamber and posterior segment, thereby redirecting aqueous flow to the anterior chamber. There are previous studies suggesting pars plana vitrectomy-hyaloidotomy-zonulectomy-iridectomy surgery which has promising outcomes in pseudophakic and aphakic patients.[9]
The current study evaluated the demography, clinical profile, and treatment outcomes of pars plana vitrectomy-hyaloidotomy-zonulectomy and iridectomy in eyes with malignant glaucoma in a tertiary care institute in South India. A total of 36 eyes of 30 patients were analyzed. Six patients had bilateral malignant glaucoma. The mean age of the study population was 70 ± 10.7 years (range, 43–88 years). A similar study by Raj et al.[1] had younger participants with a mean age of 66.40 ± 13.49 years (range, 44–83 years). A total of 56.33% of participants in the study were females. In a similar study by Debrouwere et al.,[10] the majority of the study population was female, and they described that malignant glaucoma is more common in women than in men. (70/30 ratio)[11] This can be attributed to the more forward location of the lens and a narrower space between the lens equator and ciliary body in women, resulting in a 4% shallower anterior chamber compared to men.[12]
The most common intraocular procedure that precipitated the onset of malignant glaucoma in our study was cataract surgery (67.8% eyes) followed by phaco-trabeculectomy (22.2%). Raj et al.[1] also reported that in 65% of their study participants, cataract surgery was the primary procedure, while Dave et al.[13] and Balekudaru et al.[14] reported that trabeculectomy was the most common procedure that led to the development of malignant glaucoma.
Treatment of malignant glaucoma aims to relieve the aqueous misdirection, all the participants had a trial of medical therapy with cycloplegics and topical and systemic antiglaucoma medications. Those patients who had either intraocular pressure of more than 21 mmHg or persistent flattening of the anterior chamber underwent surgery. All the eyes in this study received 1% atropine eye ointment for at least one month postoperatively, and none of them had a recurrence of malignant glaucoma post-procedure. Dave et al.[13] in their study reported that the continuation of cycloplegics can reduce the recurrences of aqueous misdirection.
There was a statistically significant reduction in intraocular pressure in every follow-up visit. A similar study by Raj et al.[1] also had a statistically significant reduction of IOP in the final follow-up visit in comparison with the presentation. A total of 97.22% of participants achieved anatomical success, and 44.44% achieved complete success in 3 months. A total success (complete and qualified success) of 91.6% was achieved. The average duration between the development of malignant glaucoma to the surgical procedure was 2.84 days. (0–19 days) The early intervention might have contributed to the increased success rate of the procedure in our study. In the study by Raj et al.,[1] the definition of complete and qualified success was slightly different from the current study, and they had a total success of 87.5% post-procedure. There are previous studies that have reported the occurrence of malignant glaucoma after vitrectomy, which fails to remove the anterior hyaloid and emphasizes the importance of the removal anterior vitreous phase. Sharma et al.,[15] in their pilot series, including five eyes, described 100% anatomical success with vitrectomy-phacoemulsification-vitrectomy in phakic eyes without recurrence at a 32 month follow-up. Harbour et al.[6] described a 90% success rate of pars plana vitrectomy in 24 eyes with a follow-up range of 89 months. A study by Debrouwere et al.[10] showed recurrence of malignant glaucoma in 75% of patients after a follow-up period of 14 days. They also observed 100% anatomical success in vitrectomy-tunnel technique. Zonulo-hyaloido-vitrectomy technique via the anterior chamber route has been described by Lois et al.,[16] where they observed no recurrence in a case series of five pseudophakic eyes with malignant glaucoma after a median follow-up of 5.5 months. Balekudaru et al.,[14] in their study, including 58 eyes with three different surgical techniques to manage malignant glaucoma, showed an overall 96.5% anatomical success rate, wherein the maximum number, i.e., 27 eyes underwent pars plana vitrectomy with zonulo-hyaloidotomy-iridectomy similar to our study.
The surgical technique of pars plana vitrectomy-hyaloidotomy-zonulectomy-iridectomy provides an adequate removal of the core vitreous and anterior vitreous with perforation of anterior hyaloid, zonules, and the iris through the pars plana route. This can create a unicameral eye reversing the aqueous misdirection and resolving the aqueous pockets. This study proves that a successful pars plana vitrectomy-hyaloidotomy-zonulectomy-iridectomy in malignant glaucoma can lead to better intraocular pressure control, a promising visual outcome, and reduced chance of recurrence.
Conclusion
Even though malignant glaucoma is considered a refractory entity, pars plana vitrectomy-hyaloidotomy-zonulectomy-iridectomy surgery can achieve favorable outcomes with reduced chances of recurrence.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Conflicts of interest
There are no conflicts of interest.
Funding Statement
Nil.
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