Aims: To determine the value of day time and 24 hour phasing in patients treated for progressive glaucoma despite apparently adequate IOP control.
Methods: A retrospective analysis of a cohort of patients that had undergone either daytime phasing (8a.m. to 6p.m.) or 24-hour phasing was conducted. IOP measurements were compared between those taken in clinic, daytime phasing, and 24-hour phasing. The frequency with which phasing results changed clinical management was also compared between daytime and 24-hour phasing.
Results: 76 patients fulfilling the study criteria were identified. Clinic and daytime phasing IOP were known for all 76 patients, night time IOP measurements were known for 41. There was no significant difference between mean IOP values measured in clinic and daytime phasing (p=0.062) or between clinic values and night time phasing (p=0.65). The mean daytime phasing IOP was significantly higher than the mean night time phasing IOP (p=0.038) (ANOVA for 3 groups, p=0.058).
There was no significant difference between the mean peak IOP in clinic or day time phasing (p=0.13) or between clinic and night time phasing (p=0.44). The mean daytime phasing IOP peak was significantly higher than the mean night time phasing IOP peak (p=0.015) (ANOVA for 3 groups, p=0.074).
There was no significant difference in the frequency of a change in management that occurred as a result of phasing between the daytime and 24-hour groups (p=0.65).
Conclusions: 24 hour phasing offers little advantage over day time phasing in identification of IOP fluctuations or peaks in patients progressing despite acceptable clinic IOP readings. Daytime phasing is likely to be more cost-effective than 24-hour phasing.