Malignant Glaucoma – Open Sesame

Malignant glaucoma is defined as high intraocular pressure (IOP), with a shallow or flat anterior chamber (AC) in the presence of a patent peripheral iridotomy (PI)[1] in the absence of any posterior segment pathology (particularly suprachoroidal haemorrhage). It is a dreadful complication that can occur during or after anterior segment surgery or even laser. Exact pathophysiology of malignant glaucoma still remains ambiguous. It has been given multiple names emphasising the presumed pathophysiology, which include infusion misdirection syndrome, acute intraoperative rock-hard eye syndrome, ciliary block glaucoma, subcapsular fluid entrapment, fluid/aqueous misdirection syndrome, malignant glaucoma, ciliolenticular block and positive vitreous pressure glaucoma.[2] A 53-year-old male presented with complaints of drop in vision, redness and pain in the right eye (RE) since 2 weeks. Patient underwent cataract surgery in RE 2 weeks ago elsewhere and was using topical antiglaucoma medications (AGMs) – eyedrops brimonidine tartrate 0.2% with brinzolamide 1% twice a day (BD), dorzolamide 2% with timolol maleate 0.5% BD, topical steroids, that is, prednisolone acetate 1% six times per day, and eyedrops atropine sulphate 1% three time per day (TID). On examination (O/E), uncorrected visual acuity in RE was perception of light with accurate projection of rays in all quadrants. The intra-ocular pressure (IOP) with Goldmann applanation tonometry (GAT) at 01:00 pm was 50 mmHg with conjunctival congestion, microcystic corneal oedema (MCE), flat anterior chamber, plastered iris as shown in Figure 1a and b, with posterior chamber intraocular lens. Fundus details could not be made out due to corneal oedema. On anterior segment optical coherence tomography (OCT), the iris was plastered to the cornea, as seen in Figure 1c.Figure 1: (a) shows flat anterior chamber on diffuse illumiation (b) shows iris plastered to cornea on 14x1mm slit (c) shows iris plastered to cornea on AS-OCTPatient was put on maximum topical medical therapy along with oral medication- tab acetazolamide 250 mg four times per day. Multiple PIs and neodymium-doped yttrium aluminium garnet (Nd-YAG) laser hyaloidotomy were done. AC remained flat with total iridocorneal touch and IOP was high in spite of a patent PI. Thus, patient was diagnosed as RE malignant glaucoma status post cataract surgery. Pars plana core vitrectomy with AC reformation and surgical peripheral iridectomy was performed in this patient. At postoperative day (POD) 1, corneal oedema decreased [Figure 2a and b], AC was well formed, there were 1+ cells, PI was patent and IOP with GAT at 09:00 am was 38 mmHg. Patient was advised to continue AGM, topical steroids, eyedrops cyclopentolate 1% TID and oral tab acetazolamide 250 mg BD.Figure 2: (a) shows formed anterior chamber with patent PI on diffuse illumination (b) shows deep anterior chamber on 14x1 mm slit (c) shows formed anterior chamber with patent PI on AS-OCTAt POD 7, patient had stopped all AGMs and was using only topical steroids. O/E RE visual acuity was 20/80 and cornea was hazy due to microcystic oedema, with a deep AC and patent PI. Fundus examination showed a cup-to-disc ratio (CDR) of 0.55, and IOP with GAT at 11:30 am was 52 mmHg. We advised him to start AGMs in RE – topical eyedrops timolol maleate 0.5% with brimonidine tartrate 0.2% BD, ripasudil 0.4% BD and dorzolamide 2% TID along with tab acetazolamide 250 mg BD. POD 14 brought wonders when the visual acuity in RE improved to 20/40, IOP with GAT at 10:00 am was 22 mmHg under AGM, with deep AC, and fundus showed a CDR of 0.55. At postoperative 1 month, anterior segment OCT was done, which showed a deep AC with a patent PI [Figure 2c]. DISCUSSION There has been a school of thought that occurrence of malignant glaucoma is closely related to anatomy, such as small eyeball, short axial length, narrow angle, rotation of ciliary processes and relatively large lens. Ciliolenticular block can be caused by these abnormal anatomical associations among the lens, ciliary body and anterior vitreous, leading to misdirection of aqueous into the vitreous.[3] Patients can present after any anterior segment surgery or laser or even spontaneously with sudden drop in vision, excruciating pain, redness and on examination, a uniformly shallow AC (both peripheral and axial shallowing) can be seen. As in any acute angle closure attack, after lowering IOP with oral and topical AGM, a PI is to be done. Persistence of these features despite a patent PI (rules out pupillary block) narrows down the diagnosis to malignant glaucoma. In 1962, Chandler and Grant[4] reported that, mydriatic– cycloplegic therapy was effective for malignant glaucoma. A standard medical regimen includes use of topical atropine two or three times daily, intravenous mannitol, topical beta blockers or alpha-2 agonists or both, and oral or topical carbonic anhydrase inhibitors. After the attack is broken, the patient should be maintained indefinitely on atropine therapy to prevent recurrences. Medical therapy is effective only in approximately one-half of these cases, that too within 5 days of presentation,[5] and persistence of this condition beyond this time frame necessitates surgical intervention. Nd-YAG laser, by disrupting the anterior hyaloid face or posterior lens capsule and hyaloid face, is effective in managing aphakic and pseudophakic malignant glaucoma. In case of non-availability of Nd-YAG laser, slit lamp needle revision is a technique in which, transcorneal needling can be tried to disrupt anterior vitreous face and reform the anterior chamber. The laser may result in shrinkage of the ciliary processes, which may decrease cilio-hyaloidal apposition and decrease posterior aqueous flow.[6] Chandler and Grant[4] reported for the first time on the use of pars plana fluid aspiration to treat this condition. Studies suggest that the sclerotomy should be placed 3 mm posterior to the limbus to break the anterior hyaloid, thereby reducing its contribution to the blockade, and postoperatively, patients are advised to be maintained on atropine to avoid recurrences.[6] The purpose of the vitrectomy is again to disrupt the anterior hyaloid face and release the fluid trapped within the vitreous. Anterior vitrectomy may require lens extraction or doing a laser photocoagulation using argon laser to photocoagulate ciliary processes directly or transscleral diode laser cyclophotocoagulation can also help treat an acute attack of malignant glaucoma.[7-9] Another approach is anterior vitrectomy via pars plana approach[10,11] and/or in combination with reformation of AC with air. Reports have shown success with iridectomy–hyaloido-zonulectomy combined with anterior vitrectomy, whether anteriorly via the iridectomy or pars plana.[12,13] In phakic patients, a vitrectomy–phacoemulsification–vitrectomy (with zonulo-hyaloidectomy–iridectomy) has shown preliminary success (i.e., limited core vitrectomy is done before cataract extraction to decompress vitreous, followed by a more thorough complete vitrectomy after lens extraction).[14] In refractory cases, a complete pars plana vitrectomy along with lens removal is likely required with thorough removal of the entire hyaloid face as well as creation of vitrectomy tunnel (defined by an iridectomy–hyaloidectomy–zonulectomy).[15] CONCLUSION Malignant glaucoma, being a challenging and dreadful complication, needs prompt diagnosis and appropriate approach to alleviate this condition and to prevent from complete vision loss. The fellow eye should always be monitored with caution as this condition is majorly due to dynamic imbalance among the lens, ciliary body and vitreous. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.