Six patients (four females, two males, mean age 63 years) with malignant glaucoma in a total of nine eyes were referred to the Department of Ophthalmology of the First Affiliated Hospital of Zhejiang Chinese Medical University between December 2016 and September 2017.
Malignant glaucoma occurred after phacoemulsification and intraocular lens implantation in five eyes, after trabeculectomy in one eye, after phacotrabeculectomy in one eye, and in two eyes with no surgical history.
Because a patent iridectomy was present and no sign of choroidal effusion or suprachoroidal hemorrhage were detected, malignant glaucoma was diagnosed.
Given the presence of anterior uveitis and the markedly shallow anterior chamber in this owl, potential mechanisms for ocular hypertension were considered to be altered aqueous humor flow within the trabecular meshwork (secondary to anterior uveitis) or at the pupil (caused by pupillary block), aqueous misdirection and expansion of the vitreous body (malignant glaucoma), or some combination of these mechanisms, as is often the case in cats.
(19-22) However, to our knowledge, aqueous misdirection or malignant glaucoma have not been reported in any avian species.
Along with other agents that decrease aqueous humor production, they are considered to be the topical hypotensive agent of choice for malignant glaucoma as they reduce the volume of aqueous humor misdirected into the vitreous, and therefore reduce the forces pushing the lens-iris diaphragm anteriorly.
It was also described as acute aqueous misdirection syndrome to differentiate it from malignant glaucoma (aqueous misdirection syndrome) which has similar clinical picture but occurs later in the postoperative period .
Another benefit is preventing postoperative malignant glaucoma which may occur in these eyes.
So far, predisposition for malignant glaucoma was found in eyes with chronic angle closure glaucoma; nevertheless, cases in which open angle glaucoma was diagnosed prior to the surgery have also been reported [1, 2].
Symptoms of inflammation in the anterior segment of the eye and previous surgical procedures were also mentioned as predisposing to malignant glaucoma .
The aim of this study was to identify preoperative risk factors for malignant glaucoma and to assess its occurrence depending on the type and nature of the primarily conducted glaucoma surgery.
Complication n (%) Early hypotony (*) 20(19) Cataract 9(9) Choroidal effusion 8(8) Tube erosion through conjunctiva 4(4) Flat anterior chamber 4(4) Tube contact with iris/endothelium 4(4) Encapsulated bleb 3(3) Bullous keratopathy 2(2) Macular oedema 2(2) Malignant glaucoma
2(2) Transient diplopia 1(1) Retinal detachment 1(1) Phthisis bulbi 1(1) Central retinal vein occlusion 1(1) Wound leak 1(1) Exacerbation of chronic uveitis 1(1) Silicone oil in anterior chamber 1(1) Corneal abrasion 1(1) Total number of complications 66 ([dagger]) eyes with complications 47(44) Mean number of complications/eyes 1.4 (*) IOP [less than or equal to]5 mmHg on any follow-up visit during the first postoperative month.