Purpose: To characterize intraocular pressure (IOP) and central corneal thickness (CCT) measurements of ocular hypertension (OHT) patients with and without frequency doubling technology (FDT) perimetry test abnormalities.
Patients and methods: In this prospective, observational, cross-sectional, comparative case series, one eye of 33 OHT patients was randomly chosen. All OHT patients had IOP > or = 23 mmHg in 2 out of 3 measurements on the test day, normal appearing discs and nerve fiber layer, and normal white on white standard automated perimetry (SAP). Several IOP calculations (outpatient IOP, highest office IOP, mean office IOP, office IOP fluctuation, and office IOP peak), CCT, SAP and FDT parameters were compared between OHT patients with repeatable FDT perimetry abnormality and normal FDT perimetry.
Results: Eight (24%) of 33 OHT patients had an abnormal FDT perimetry test. The median office IOP fluctuation (5.0 vs 2.0, P = 0.007), office IOP peak (3.2 vs 1.0, P = 0.004), and FDT pattern standard deviation (PSD) (5.03 v 3.32, P = 0.000) were significantly higher in OHT patients with repeatable FDT perimetry test abnormalities compared to OHT patients with normal FDT perimetry test. Office IOP fluctuation and office IOP peak were significantly correlated with both number of significantly depressed FDT points and FDT PSD index. CCT measurements and SAP global indices did not differ significantly in OHT patients with and without FDT perimetry test abnormality.
Conclusion: Our results suggest that currently diagnosed OHT patients who have large office IOP fluctuations and office IOP peaks are more likely to have repeatable FDT perimetry test abnormalities. These results suggest that OHT patients with large IOP fluctuations and IOP peaks are more likely to have early glaucomatous damage, and this should be taken into account when assessing the risk of conversion to primary open angle glaucoma.