Genetics and Glaucoma
Glaucoma runs in families. Research now shows that up to 89% of familial glaucoma is genetically determined. Understanding your genetic risk doesn't just tell you if you might develop glaucoma — it helps your doctor decide how to treat it.
Glaucoma Is a Genetic Disease
For decades, glaucoma was understood primarily through intraocular pressure. High pressure damages the optic nerve; lower the pressure, slow the damage. That's still true — but it's incomplete.
Large population studies have revealed that genetics play a far larger role than previously appreciated. The Baltimore Eye Survey found that siblings of glaucoma patients are nearly 4 times more likely to develop the disease. A Dutch population study estimated that first-degree relatives face a 22% lifetime risk — compared to just 2.3% in the general population.
But genetics isn't about one gene. Adult-onset glaucoma is a complex polygenic disease. Harvard researchers have identified over 127 genetic loci associated with glaucoma, spanning pathways involved in extracellular matrix metabolism, cell signaling, and ocular development. No single variant causes glaucoma, but together they create meaningful differences in who gets it and how fast it progresses.
What the Research Shows
Three landmark studies demonstrate why genetics matter for glaucoma care.
9x
higher lifetime risk
First-degree relatives of glaucoma patients have a 22% lifetime risk of developing the disease, compared to 2.3% in the general population.
Wolfs et al., Archives of Ophthalmology, 1998
3.7x
higher risk for siblings
Siblings of glaucoma patients are 3.7 times more likely to develop the disease. The Baltimore Eye Survey also found higher odds ratios in Black patients.
Tielsch et al., Archives of Ophthalmology, 1994
89%
genetically determined
Population-based research estimates that 89% of the familial occurrence of glaucoma is genetically determined, not environmental.
Wolfs et al., Archives of Ophthalmology, 1998
127+
genetic variants identified
Genome-wide association studies have identified over 127 loci associated with glaucoma and related traits. Individually small, together they create meaningful risk differences.
Wang & Wiggs, Cold Spring Harbor Perspectives in Medicine, 2014
The Doctor's Decision: Where Genetics Changes Everything
When your ophthalmologist reviews your visual field test, OCT scan, and IOP readings, they're making a judgment call. Things don't look great — but how aggressively should they intervene? The answer has always been part science, part clinical intuition.
Your doctor generally has four options, each escalating in invasiveness:
Observation
Watch and wait
For early-stage glaucoma or borderline cases, your doctor may choose careful monitoring with regular visual field tests, OCT scans, and IOP checks. No treatment is started yet.
How genetic risk changes this: A low PRS score may give the doctor more confidence that observation is safe. A high score may prompt them to skip this step entirely.
Medicated Eye Drops
First-line treatment
Prescription drops lower IOP by reducing fluid production or improving drainage. They require daily compliance, sometimes multiple times per day, and can have side effects like redness, stinging, or changes in eye color.
How genetic risk changes this: If genetic risk is elevated, the doctor may set a more aggressive target pressure or start combination therapy sooner rather than trying one drop at a time.
SLT (Selective Laser Trabeculoplasty)
Minimally invasive laser
A quick, in-office laser procedure that improves the eye’s natural drainage. It’s technically classified as surgery but involves no incisions. Effects can last 3–5 years, and it can be repeated.
How genetic risk changes this: For high-risk patients, some doctors are now offering SLT as a first-line treatment rather than drops — the LiGHT trial showed it can be more effective and more cost-efficient than starting with drops.
Surgery
Incisional procedures
When drops and laser aren’t enough, surgery creates a new drainage pathway. Options include trabeculectomy, tube shunts, and newer MIGS procedures. These carry more risk but can achieve the lowest pressures.
How genetic risk changes this: A high genetic risk score can help justify earlier surgical intervention to patients and insurance companies — preventing damage is far better than trying to recover lost vision.
The patient's perspective
If you're the patient in the chair and your doctor is weighing whether to observe, prescribe, or intervene — you want them to have every available piece of information. Your IOP tells them what's happening now. Your OCT shows the structural damage. Your visual field maps what vision you've lost. But none of those tests tell your doctor about the genetic cards you were dealt. That's the gap SightScore™ fills.
The Complete Diagnostic Picture
VF, IOP, and OCT tell your doctor what's happening. SightScore™ tells them why — and what's likely next.
Visual Field (VF)
What it does: Maps your peripheral vision to detect blind spots
Why it matters: Shows functional vision loss — what you can actually see
IOP Measurement
What it does: Measures the fluid pressure inside your eye
Why it matters: The only modifiable risk factor — lowering IOP slows progression
OCT Scan
What it does: Images the nerve fiber layer and optic nerve head
Why it matters: Detects structural damage before you notice vision changes
SightScore™ (PRS)
What it does: Analyzes 7M+ genetic variants from a saliva sample
Why it matters: Reveals inherited risk that no eye exam can measure — helps guide how aggressively to treat
What This Means for Your Family
Because glaucoma is heavily genetic, your SightScore™ result has implications beyond your own care. If your risk is elevated, your siblings, children, and parents may share that predisposition.
The Baltimore Eye Survey found that the risk is strongest among siblings (odds ratio 3.7), followed by parent-child relationships (odds ratio 2.2). These numbers are even higher in Black families.
A SightScore™ result can be the conversation starter that gets your family members screened — potentially years before they would have been otherwise. Early detection in family members means treatment can begin before vision loss.
Published Research
Wolfs RCW, Klaver CCW, Ramrattan RS, et al.
“Genetic Risk of Primary Open-angle Glaucoma: Population-Based Familial Aggregation Study.” Archives of Ophthalmology, 1998; 116(12):1640–1645.
Tielsch JM, Katz J, Sommer A, Quigley HA, Javitt JC.
“Family History and Risk of Primary Open Angle Glaucoma: The Baltimore Eye Survey.” Archives of Ophthalmology, 1994; 112(1):69–73.
Wang R, Wiggs JL.
“Common and Rare Genetic Risk Factors for Glaucoma.” Cold Spring Harbor Perspectives in Medicine, 2014; 4(12):a017244.
Give Your Doctor the Full Picture
SightScore™ is a simple at-home saliva test that reveals the genetic risk your eye exams can't measure. Results in 2–4 weeks. $449.