Glaucoma Suspect with Discordant Pressure and Field
A 61-year-old woman is referred for glaucoma evaluation. She is asymptomatic. Central corneal thickness is 545 µm OD and 552 µm OS. Goldmann applanation pressures today are 24 mmHg OD and 23 mmHg OS; last year they were 19 and 18 mmHg in the same practice. Optic discs show a vertical cup-to-disc ratio of 0.7 OD and 0.6 OS with mild inferotemporal rim thinning bilaterally and no disc hemorrhage. Standard automated perimetry (24-2, reliable indices) shows a mean deviation of -1.8 dB OD and -2.2 OS with no clusters; glaucoma hemifield test is borderline in both eyes. She has hypertension controlled with amlodipine, no diabetes, no family history, and no history of steroid use. She asks whether she has glaucoma and whether she should start drops today.
1. Synthesize the findings into a risk assessment and a defensible diagnostic label.
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This is best characterized as glaucoma suspect / ocular hypertension with borderline structural and functional findings, not established glaucoma. Key reasoning:
- Pressures are elevated but not extreme, and the rise from 19/18 to 24/23 is meaningful but could reflect diurnal variation, measurement technique, or time of day. Repeat at different times, ideally with the same instrument and observer, and consider a diurnal curve.
- Central corneal thickness is average, so the pressures are not artifactually high from a thick cornea; this slightly increases concern relative to a thick cornea.
- Discs show mild inferotemporal thinning - the most common early glaucomatous pattern - but no hemorrhage and no clear focal notching. Baseline disc photography or OCT retinal nerve fiber layer is essential to detect change over time.
- Fields are borderline with no reproducible cluster; a single borderline test in a reliable patient is not diagnostic. Repeat perimetry to look for reproducibility.
The honest answer to the patient: "You do not meet criteria for glaucoma today, but you are at elevated risk and need monitoring." Document risk factors (age, IOP, thin-ish average cornea, disc appearance) and set a follow-up interval of 3–6 months with repeat fields and imaging.
2. She pushes for treatment now. Justify a management decision that respects both evidence and her preferences.
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Treatment of a suspect is a risk-benefit judgment, not a reflex. Two defensible paths:
Observe if the risk is judged low-to-moderate: repeat IOP, fields, and OCT at 3–6 months to establish whether progression or reproducible defect exists. Advantages: avoids lifelong therapy, cost, preservative exposure, and side effects in someone who may never convert.
Treat if risk is judged high (higher IOP, confirmed structural change, reproducible field defect, strong family history, thin cornea, older age). A prostaglandin analog once nightly is first-line for efficacy and convenience; warn about hyperemia, iris darkening, periorbital fat changes, and eyelash growth.
Either way:
- Set a target pressure (e.g., 20–30% reduction from baseline) and a review interval.
- Obtain baseline imaging and fields before deciding, because without baseline you cannot judge progression later.
- Address the blood pressure: noctural dipping in a treated hypertensive can worsen optic nerve perfusion; coordinate with her physician rather than ignoring it.
- Document the shared decision - what was discussed, her preference, and the agreed plan. That documentation is what protects both the patient and the clinician if the disease progresses.
If any reproducible defect or clear rim change appears, move to treatment without further delay.