In the OHTS (Ocular Hypertension Treatment Study), which baseline factor was identified as the most powerful predictor of conversion from ocular hypertension to glaucoma?
- A Thin central corneal thickness (CCT < 555 μm) ✓
- B IOP level > 26 mmHg at baseline
- C Large cup-to-disc ratio > 0.6
- D Age > 65 years
Explanation
The OHTS (Ocular Hypertension Treatment Study) enrolled patients with OHT (IOP 24-32 mmHg, normal disc, normal VF) and found that thin central corneal thickness (CCT) was the single most powerful predictor of conversion to POAG. Eyes with CCT < 555 μm had a 3.4-fold higher risk of conversion than eyes with CCT > 588 μm. The mechanism is twofold: (1) thin corneas may cause systematic underestimation of true IOP by Goldmann applanation tonometry — the actual IOP may be significantly higher than measured; and (2) thin corneas may represent a primary connective tissue vulnerability predisposing the optic nerve head lamina cribrosa to glaucomatous damage. OHTS showed that topical IOP-lowering drops (any class) reduced 5-year conversion risk from 9.5% to 4.4%.
Reference: Khurana Comprehensive Ophthalmology, 7th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.