Background/aims: To examine the frequency of abnormal retinal nerve fibre layer thickness (RNFLT) and ganglion cell complex (GCC) measurements among healthy and glaucoma suspect and preperimetric glaucoma (GSPPG) eyes in a prospective longitudinal study. Methods: Normal and GSPPG eyes with ≥18 months follow-up were included. Spectral-domain optical coherence tomography (SDOCT) was performed annually in normal and biannually in GSPPG eyes. One eye was randomly selected for inclusion. RNFLT and GCC parameters with p>5% were classifi ed as 'within normal limits (WNL) ' and p<1% were classified as 'outside normal limits (ONL)'. Results: 23 normal and 74 GSPPG eyes were followed for a mean 43.4±9.6 months. During serial follow-up, 100% and 91% of normal eyes had all RNFLT and GCC parameters classified as WNL, respectively. 27 (37%) and 17 (23%) of GSPPG eyes had an ONL classification in at least one RNFLT and GCC parameter, respectively. A high percentage (41%-56%) of RNFLT and GCC measurements classified as ONL were not replicated on subsequent scans. The rates of loss for all parameters were similar (p>0.05) between the groups. Conclusions: Specificity in this sample of healthy eyes was very high for RNFLT and GCC parameters. Confirmation of suspected SDOCT abnormalities is recommended to differentiate reproducible loss from long-term variability.
ASJC Scopus subject areas
- Sensory Systems
- Cellular and Molecular Neuroscience