Increased-resolution OCT thickness mapping of the human macula: a statistically based registration.
OBJECTIVE
To describe the development of a technique that enhances spatial resolution of retinal thickness maps of the Stratus OCT (Carl Zeiss Meditec, Inc., Dublin, CA). A retinal thickness atlas (RT-atlas) template was calculated, and a macular coordinate system was established, to pursue this objective.


METHODS
The RT-atlas was developed from principal component analysis of retinal thickness analyzer (RTA) maps acquired from healthy volunteers. The Stratus OCT radial thickness measurements were registered on the RT-atlas, from which an improved macular thickness map was calculated. Thereafter, Stratus OCT circular scans were registered on the previously calculated map to enhance spatial resolution.


RESULTS
The developed technique was applied to Stratus OCT thickness data from healthy volunteers and from patients with diabetic retinopathy (DR) or age-related macular degeneration (AMD). Results showed that for normal, or close to normal, macular thickness maps from healthy volunteers and patients with DR, this technique can be an important aid in determining retinal thickness. Efforts are under way to improve the registration of retinal thickness data in patients with AMD.


CONCLUSIONS
The developed technique enhances the evaluation of data acquired by the Stratus OCT, helping the detection of early retinal thickness abnormalities. Moreover, a normative database of retinal thickness measurements gained from this technique, as referenced to the macular coordinate system, can be created without errors induced by missed fixation and eye tilt.
Bernardes
Rui
R
Centro de Novas Tecnologias para a Medicina da Associação para a Investigação Biomédica e Inovação em Luz e Imagem, Azinhaga Sta Comba, Celas, Coimbra, Portugal. rcb@aibili.pt
Santos
Torcato
T
Cunha-Vaz
José
J
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003930:Diabetic Retinopathy / Q000175:diagnosis*; D003941:Diagnostic Techniques, Ophthalmological; D006801:Humans; D008266:Macula Lutea / Q000473:pathology*; D008268:Macular Degeneration / Q000175:diagnosis*; D008433:Mathematics; D008875:Middle Aged; D008962:Models, Theoretical; D041623:Tomography, Optical Coherence / Q000295:instrumentation / Q000379:methods*