Findings
Enlarged cup-to-disc ratio (>0.6), neuroretinal rim thinning violating the ISNT rule (I>S>N>T), disc pallor, possible Drance hemorrhages (splinter hemorrhages at disc margin = active damage), bayoneting of vessels as they exit the deep cup.
Case 12 - Oncology, glaucoma, and pediatric alignment
Incidental Bilateral Optic Disc Cupping
55-year-old man - Asymptomatic - Routine physical exam - Bilateral enlarged cup-to-disc ratio
Case 12Primary Open-Angle Glaucoma
Clinical Presentation
A 55-year-old man comes in for a routine physical examination. Your ophthalmoscopic examination reveals the findings illustrated in the photograph in both optic discs.
Learner Questions
- Describe these ophthalmoscopic findings.
- What is the differential diagnosis?
- What additional information is needed to confirm your diagnosis?
- What would be the most likely diagnosis?
- Discuss the general principles of treatment.
Answer Framework
Diagnosis
Primary Open-Angle Glaucoma (POAG) - progressive optic neuropathy with corresponding visual field loss in an open anterior chamber angle. A clinical diagnosis requiring BOTH structural (disc/RNFL) AND functional (visual field) evidence.
DDx
POAG (most likely - bilateral, insidious, asymptomatic), Normal Tension Glaucoma (C/D changes with IOP <=21 mmHg), Physiologic large cup (symmetric, normal fields, normal IOP - diagnosis of exclusion), Secondary glaucoma (pseudoexfoliation, pigmentary, steroid- induced, uveitic), Optic atrophy from ischemia or compression.
Treatment
Lower IOP to target pressure. Medical: prostaglandin analogs (most effective, qd), β- blockers (timolol), CAIs (dorzolamide), α-2 agonists (brimonidine), rho-kinase inhibitors (netarsudil). Laser: SLT (LiGHT trial - first-line = drops at 3 years). Surgery: trabeculectomy, MIGS (iStent, GATT), tube shunt. Avoid CAIs in sickle cell (acidosis -> sickling).
Additional workup
Tonometry (Goldmann applanation IOP), CCT pachymetry (thin cornea underestimates true 3 IOP), Humphrey VF 24-2 SITA (arcuate scotomas, nasal steps), OCT RNFL + optic nerve (structural damage precedes field loss), Gonioscopy (open angle confirmed; rule out secondary causes). History: family history, African ancestry, steroid use, myopia, prior trauma.
Teaching Pearl
ISNT rule: normal neuroretinal rim = Inferior > Superior > Nasal > Temporal. Violation = glaucoma until proven otherwise. 'Slient thief of sight' - 40% of nerve fibers lost before symptoms. African-Americans: 4x prevalence, earlier onset, faster progression - screen aggressively. LiGHT trial: SLT as first-line therapy is equivalent to drops at 3 years.
Original answer transcript
Findings Diagnosis Enlarged cup-to-disc ratio (>0.6), neuroretinal rim thinning violating the ISNT rule Primary Open-Angle Glaucoma (POAG) - progressive optic neuropathy with corresponding (I>S>N>T), disc pallor, possible Drance hemorrhages (splinter hemorrhages at disc margin = visual field loss in an open anterior chamber angle. A clinical diagnosis requiring BOTH active damage), bayoneting of vessels as they exit the deep cup. structural (disc/RNFL) AND functional (visual field) evidence. DDx Treatment POAG (most likely - bilateral, insidious, asymptomatic), Normal Tension Glaucoma (C/D Lower IOP to target pressure. Medical: prostaglandin analogs (most effective, qd), β- changes with IOP <=21 mmHg), Physiologic large cup (symmetric, normal fields, normal IOP blockers (timolol), CAIs (dorzolamide), α-2 agonists (brimonidine), rho-kinase inhibitors - diagnosis of exclusion), Secondary glaucoma (pseudoexfoliation, pigmentary, steroid- (netarsudil). Laser: SLT (LiGHT trial - first-line = drops at 3 years). Surgery: trabeculectomy, induced, uveitic), Optic atrophy from ischemia or compression. MIGS (iStent, GATT), tube shunt. Avoid CAIs in sickle cell (acidosis -> sickling). Additional workup Tonometry (Goldmann applanation IOP), CCT pachymetry (thin cornea underestimates true 3 IOP), Humphrey VF 24-2 SITA (arcuate scotomas, nasal steps), OCT RNFL + optic nerve (structural damage precedes field loss), Gonioscopy (open angle confirmed; rule out secondary causes). History: family history, African ancestry, steroid use, myopia, prior trauma. TEACHING PEARL ISNT rule: normal neuroretinal rim = Inferior > Superior > Nasal > Temporal. Violation = glaucoma until proven otherwise. 'Slient thief of sight' - 40% of nerve fibers lost before symptoms. African-Americans: 4x prevalence, earlier onset, faster progression - screen aggressively. LiGHT trial: SLT as first-line therapy is equivalent to drops at 3 years.