Secondary glaucoma

Secondary glaucoma is a collection of progressive optic nerve disorders associated with a rise in intraocular pressure (IOP) which results in the loss of vision.

Principal causes of secondary glaucoma include optic nerve trauma or damage,[2] eye disease, surgery, neovascularization,[3] tumours[4] and use of steroid and sulfa drugs.

[5] Common treatments are designed according to the type (open-angle or angle-closure) and the underlying causative condition, in addition to the consequent rise in IOP.

Primary IOL implantation is observed to significantly reduce and avoid the occurrence of secondary glaucoma in paediatric patients under the age of two.

This is due to two main reasons, the blockage of vitreous flow resulting from inflammation in the structures of the trabecular meshwork, and the sedimentation of inflamed cells.

Specifically for viral anterior uveitis, patients with IOP levels above 30 mmHg are often suffer from secondary glaucoma caused by cytomegalovirus.

[2] However, given the derived nature of secondary glaucoma, there may be no significant association between age, ethnicity or gender and the prevalence of the condition.

[5] Due to lack of concrete and specific epidemiological evidence, further research is required to accurately estimate the prevalence of secondary glaucoma and its subtypes.

[9] Uveitis is the inflammation of the uvea, a middle layer tissue of the eye consisting of the ciliary body, choroid and iris.

This results in the accumulation of aqueous and thus elevated IOP, which is a common risk factor for the progression of secondary glaucoma.

[4] The blockage of vitreous flow due to inflammation in the structures of the trabecular meshwork is also observed in herpetic anterior uveitis patients.

There is an increased risk of development of posterior synechiae in glaucoma secondary to exfoliation syndrome and ocular trauma.

[2] Other side effects include increased risk of miosis-induced headaches, blurred vision, retinal detachment and damage to the blood-aqueous barrier.

It was previously identified that the side effects comprise damage to the blood-aqueous barrier, cystoid macular oedema, risk of developing anterior uveitis and recurrence of keratitis caused by herpes simplex virus.

[6] For uveitic glaucoma, treatment with selective laser trabeculoplasty is associated with fewer adverse effects and risks of failure.

Such methods work by facilitating aqueous outflow through the modification of the obstructing trabecular meshwork using trabeculectomy, goniotomy, non-penetrating deep sclerectomy or canaloplasty.

[2][6] Minimally invasive glaucoma surgery is performed in order to overcome the risks and adverse effects associated with conventional surgical procedures.

[6] In addition to the direct reduction of IOP, surgical procedures are used to remove blood, viscoelastic fluid and debris in glaucoma caused by cataract extraction and ocular trauma.