Intersession repeatability of optical coherence tomography measures of retinal thickness in early age-related macular degeneration.
OBJECTIVE
To determine the intersession repeatability of Stratus optical coherence tomography (OCT) measures of retinal thickness in patients with age-related macular degeneration (AMD).


METHODS
Measurement of retinal thickness was performed over four sessions over 12 weeks using a standardized OCT protocol with the fast macular thickness map in 67 non-treated eyes of 67 patients with AMD enrolled in a clinical trial. The intrapatient standard deviation (S(w) ) and 95% coefficient of repeatability (CR) (1.96×√2×S(w)), expressed in μm and as a percentage of mean retinal thickness, were calculated to estimate intersession repeatability.


RESULTS
The CR was 32 μm for the average retinal thickness in the central 1 mm A1 subfield [95% confidence interval (CI) 31-33 μm] and 53 μm (95% CI 51-55 μm) for the centre-point thickness (CPT). When expressed as a percentage, the CR was 15% (95% CI 14-16) for the central 1 mm A1 subfield and 29% (95% CI 27-30) for the CPT measure.


CONCLUSIONS
The average central 1 mm (A1) subfield retinal thickness measure shows good intersession repeatability in patients with stable, early AMD with poorer repeatability for the CPT measure. The results suggest that a change in Stratus OCT retinal thickness of more than 32 μm in the central A1 subfield is more indicative of true clinical change in these patients.
Moorfields Eye Hospital, London, UK. praveenjpatel@yahoo.co.uk
Praveen J
PJ
Patel
Fred K
FK
Chen
Felicia
F
Ikeji
Adnan
A
Tufail
D000368:Aged; D020256:Choroidal Neovascularization / Q000175:diagnosis*; D005260:Female; D005451:Fluorescein Angiography; D057092:Geographic Atrophy / Q000175:diagnosis*; D006801:Humans; D008268:Macular Degeneration / Q000175:diagnosis*; D008297:Male; D015203:Reproducibility of Results; D012160:Retina / Q000473:pathology*; D041623:Tomography, Optical Coherence / Q000295:instrumentation*; D014792:Visual Acuity / Q000502:physiology