Open angle glaucoma causes –
**Core Concept**
Open-angle glaucoma is a progressive optic neuropathy characterized by a slow but irreversible loss of retinal ganglion cells, leading to visual field defects. This condition is associated with increased intraocular pressure (IOP), which damages the optic nerve head.
**Why the Correct Answer is Right**
The pathogenesis of open-angle glaucoma involves the imbalance between aqueous humor production and outflow. In normal individuals, the trabecular meshwork efficiently drains aqueous humor into Schlemm's canal. However, in open-angle glaucoma, the trabecular meshwork becomes less efficient, leading to increased IOP. This increased pressure causes damage to the optic nerve head, resulting in progressive vision loss.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because open-angle glaucoma is not primarily caused by a blockage in the trabecular meshwork, as seen in angle-closure glaucoma. Open-angle glaucoma is characterized by an open angle between the iris and the cornea.
**Option B:** This option is incorrect because open-angle glaucoma is not primarily caused by a blockage in the anterior chamber angle, as seen in angle-closure glaucoma. Open-angle glaucoma is characterized by an open angle between the iris and the cornea.
**Option C:** This option is incorrect because open-angle glaucoma is not primarily caused by a blockage in the Schlemm's canal, as seen in neovascular glaucoma. Open-angle glaucoma is characterized by an imbalance between aqueous humor production and outflow.
**Clinical Pearl / High-Yield Fact**
It's essential to remember that open-angle glaucoma is often asymptomatic in its early stages, and patients may not experience visual symptoms until significant damage has occurred. Regular eye examinations, particularly in individuals with a family history of glaucoma, are crucial for early detection and treatment.
**Correct Answer: D. Increased intraocular pressure (IOP) leading to optic nerve damage.**