Glaucoma: Open-Angle and Angle-Closure Glaucoma

Vocabulary practice flashcards covering medical therapies, laser options, MIGS devices, filtering surgeries, and angle-closure mechanisms in glaucoma.

Carbonic Anhydrase Inhibitors

A class of antiglaucoma medications (e.g., Acetazolamide, Brinzolamide, Dorzolamide) that work by decreasing aqueous solution production; they are contraindicated in patients with a sulfa allergy.

Acetazolamide

A carbonic anhydrase inhibitor used in the medical treatment of primary open-angle glaucoma (POAG) that is not administered topically.

Dorzolamide

A carbonic anhydrase inhibitor used for the medical management of glaucoma in children.

Latanoprostene Bunod

A nitric oxide-donating prostaglandin analogue that breaks down into Latanoprost (which increases uveoscleral outflow) and Butanediol (which donates nitric oxide to relax the trabecular meshwork and increase trabecular outflow).

Netarsudil

A Rho kinase inhibitor that decreases aqueous production by inhibiting norepinephrine transport and increases trabecular outflow by promoting actin-myosin contraction.

Cornea Verticillata

An ocular adverse effect characterized by spindle-shaped corneal deposits, seen with the use of Rho kinase inhibitors such as Netarsudil.

Argon Laser Trabeculoplasty (ALT)

A laser procedure that causes photocoagulation and induces fibrosis in one part of the trabecular meshwork, pulling and opening the surrounding mesh on the opposite side to repair outflow.

Selective Laser Trabeculoplasty (SLT)

A laser trabeculoplasty applying a frequency-doubled Nd:YAG laser ($532\,nm$) selectively to the pigmented trabecular meshwork; it is the treatment of choice for prophylaxis in the fellow eye.

Trabeculectomy

A filtering surgical procedure in which a fistula is created between the anterior chamber and the subtenon space to lower intraocular pressure.

Fistula Fibrosis

The most common cause of trabeculectomy failure, prevented intraoperatively and postoperatively using antimetabolite agents such as mitomycin C and 5-fluorouracil (5-FU).

Non-Penetrating Glaucoma Surgeries

Surgical procedures such as deep sclerectomy and viscocanalostomy that bypass the trabecular meshwork and carry a lower risk of postoperative complications compared to penetrating surgeries.

iStent Micro Bypass

A canal-based micro-incision glaucoma surgery (MIGS) device made of heparin-coated, non-ferromagnetic titanium inserted into Schlemm's canal via a $1.5\,mm$ corneal incision to increase trabecular outflow.

CyPass Microstent

A $6.35\,mm$ suprachoroidal tube implant made of polyamide material that increases uveoscleral outflow; viable for patients with elevated episcleral venous pressure.

XEN Gel Stent

A $6\,mm$ translimbal subconjunctival tube implant composed of gelatin that increases aqueous outflow into the subtenon space, indicated for refractory glaucoma in patients with failed prior surgical treatment.

Glaucoma Drainage Devices (Seton Surgery)

Non-microincision shunt implants (such as Ahmed glaucoma valve, Baerveldt, Molteno, and stainless steel shunts) indicated in refractory glaucoma, controlled glaucoma, and glaucoma associated with aniridia.

Primary Angle Closure Glaucoma (PACG)

Also known as acute congestive glaucoma; a condition characterized by closure of the anterior chamber angle, most commonly occurring in young adults aged $20-40\text{ years}$.

Relative Pupillary Block

The initial mechanism of angle-closure glaucoma wherein apposition of the iris against the lens prevents aqueous humor from passing from the posterior chamber to the anterior chamber.

Iris Bombe

Anterior bowing of the iris resulting from elevated aqueous pressure in the posterior chamber, leading to iridotrabeculocorneal contact and presenting with a central deep anterior chamber and peripheral shallow anterior chamber.

Peripheral Anterior Synechiae (PAS)

Permanent adhesions formed between the peripheral iris, the trabecular meshwork, and the cornea due to persistent anterior displacement of the iris in angle-closure glaucoma.

Plateau Iris

An anteriorly located iris configuration that acts as an anatomical risk factor for primary angle closure glaucoma.

Primary Angle Closure Suspect (PACS)

A stage of angle closure characterized by iridotrabeculocorneal appositional contact in $\ge 3$ quadrants, accompanied by normal intraocular pressure and a normal optic disc.

Primary Angle Closure (PAC)

A stage of angle closure characterized by elevated intraocular pressure and the presence of peripheral anterior synechiae, but with a normal optic disc and visual field.

Atropine Contraindication in PACG

A clinical rule stating that pupillary dilatation agents like atropine are contraindicated in angle closure because mid-dilatation of the pupil precipitates acute angle closure.