How common is narrow angle and acute angle, closure, glaucoma, and chronic narrow angle glaucoma?

Glaucoma is optic nerve damage that can lead to blindness if not, diagnosed early and treated properly. A few years ago, one of my colleagues saw a patient on a Saturday and did not have access to the Pentacam machine. nobody noticed the patient had narrow angles, and the patient proceeded to go into angle closure the next day. Lucky for the patient she did not lose vision permanently, but it was a wake up. Call to remind our team to be on the lookout always for narrow angle. Even with our amazing technology, narrow angle can be missed. It's hard to know which patients will have no issues living with their narrow angle and which patient will go into angle closure, even with the most advanced technology in the world. The incidence (ie. how often a new case is identified in a certain timeframe for a certain population) of narrow angle (ie the inside eye drain is not fully open) and angle closure glaucoma (both acute --"possible sudden blindness risk" and chronic --slower blindness risk) in the United States and Europe is surprisingly high based on available data: United States: • Narrow Angle Glaucoma (Primary Angle Closure Suspect - PACS): ◦ The prevalence of anatomically narrow angles (which includes PACS) in the U.S. population can be inferred from broader statistics. One study suggests that about 10.35% of the population might have narrow irido-corneal angles. • Acute Angle Closure Glaucoma (AACG): ◦ The incidence of acute angle-closure glaucoma in the U.S. is relatively low. Specific numbers are harder to come by, but it’s known that acute attacks are less common than chronic forms. An estimate from one study suggests an incidence of around 2.2 cases per 100,000 persons per year, but this figure is more commonly cited for European populations, suggesting U.S. rates might be similar. • Chronic Angle Closure Glaucoma (CACG): ◦ Chronic forms of angle closure glaucoma are more common than acute attacks. The exact incidence isn’t well-documented in broad U.S. studies, but it’s part of the broader statistic where approximately one-third of all glaucoma cases globally are due to angle closure glaucoma, with the U.S. having a lower proportion due to the predominance of open-angle glaucoma. Europe: • Narrow Angle Glaucoma (PACS): ◦ Similar to the U.S., a significant portion of the European population might have narrow angles. However, exact figures for prevalence are not uniformly documented across all countries. • Acute Angle Closure Glaucoma (AACG): ◦ In Europe, the incidence of acute closed-angle glaucoma has been reported to be between 2.2 to 4.1 cases per 100,000 persons per year. This condition is considered an ophthalmological emergency due to the rapid onset and potential for severe vision loss. • Chronic Angle Closure Glaucoma (CACG): ◦ Chronic angle closure is less dramatic but more prevalent than acute attacks. In Europe, as in the U.S., it’s part of the broader category where angle closure glaucoma accounts for a significant portion of glaucoma cases, though less than open-angle glaucoma. The prevalence of primary angle closure glaucoma in Europe in 2013 was estimated at about 1.41 million people between the ages of 40 and 80 years, which includes both acute and chronic forms. Summary: • Both regions: ◦ Acute angle closure glaucoma is less common but represents an emergency with potentially severe consequences. ◦ Chronic angle closure glaucoma develops more insidiously and is more prevalent than acute forms but still accounts for a smaller portion of total glaucoma cases compared to open-angle glaucoma. • Risk Factors: ◦ Risk factors for both acute and chronic forms include anatomical predispositions like shallow anterior chambers, older age, Asian descent, and female sex, although these demographics can vary in prevalence and impact between the U.S. and Europe. This data represents approximations based on available research and might not reflect the most current data or account for all regional or demographic variations within these large areas. There is a genetic component that is not clearly understood although environmental factors play a role as well. Based on the available research, here are some genes associated with narrow angle, acute angle closure, and chronic angle closure glaucoma, along with their chromosomal locations: Genes Associated with Angle Closure Glaucoma: 1 MFRP (Membrane Frizzled-Related Protein) ◦ Chromosome: 11q23.3 ◦ Role: Linked to microphthalmia and nanophthalmos, which can result in a shallow anterior chamber and thus narrow angles. Some studies show an association with angle closure glaucoma, particularly in certain populations. 2 VSX2 (Visual System Homeobox 2, also known as CHX10) ◦ Chromosome: 14q24.3 ◦ Role: Mutations have been linked to microphthalmia, which can predispose to angle closure glaucoma. 3 COL1A2 (Collagen Type I Alpha 2 Chain) ◦ Chromosome: 7q22.1 ◦ Role: Identified in animal models (Basset Hounds) with acute angle closure glaucoma, suggesting a role in collagen composition affecting eye structure. 4 RAB22A ◦ Chromosome: 20q13.33 ◦ Role: Also noted in animal models with acute angle closure, involved in cellular processes that might affect eye development. 5 NEB (Nebulin) ◦ Chromosome: 2q23.3 ◦ Role: Another gene from animal studies associated with PACG, linked to muscle and possibly eye tissue structure. 6 FERMT2 ◦ Chromosome: 14q22.1 ◦ Role: Identified in GWAS for PACG, possibly affecting cell adhesion and tissue integrity. 7 EPDR1 ◦ Chromosome: 7p14.1 ◦ Role: Linked through GWAS to PACG risk, function in eye tissue unclear but related to endoplasmic reticulum function. 8 GLIS3 ◦ Chromosome: 9p24.2 ◦ Role: Associated with PACG in GWAS, involved in transcriptional regulation. 9 CHAT (Choline Acetyltransferase) ◦ Chromosome: 10q11.23 ◦ Role: Identified in GWAS, possibly influencing neurotransmitter function in the eye. 10 CALCRL (Calcitonin Receptor Like Receptor) ◦ Chromosome: 2q11.2 ◦ Role: Some studies suggest a link with acute but not chronic PACG, involved in vasodilation and potentially affecting aqueous humor dynamics. 11 COL18A1 ◦ Chromosome: 21q22.3 ◦ Role: Encodes type XVIII collagen, mutations have been linked to angle closure in specific families, emphasizing the role of extracellular matrix in glaucoma. 12 PCMTD1 and ST18 ◦ Chromosome: 8q (between these two genes) ◦ Role: Identified in association studies for PACG, involved in protein stability and cell cycle regulation, respectively. 13 COL11A1 ◦ Chromosome: 1p21.1 ◦ Role: Encodes a collagen type involved in scleral integrity, GWAS linked to PACG. 14 PLEKHA7 ◦ Chromosome: 11p15.1 ◦ Role: Related to cell adhesion, GWAS implicated in PACG risk. Notes: • These genes are part of ongoing research, and not all are definitively causal for angle closure glaucoma in humans. Many findings come from GWAS or animal models, and human associations often require further validation. • The presence of a gene variant does not guarantee the development of glaucoma; it may simply increase susceptibility. • The list is not exhaustive but includes genes mentioned in the context of angle closure glaucoma according to recent studies. Remember, genetic predisposition is just one piece of the puzzle; environmental factors, age, and other health conditions also play significant roles in the development of these eye conditions.