Abstract
Purpose:
To mathematically analyze the anatomical changes in the normal fovea according to age
Methods:
2,912 spectral domain optical coherence tomography (SD-OCT, Spectralis®, Heidelberg Engineering, Germany) normal foveal scans were analyzed. Subjects scanned were healthy individuals, with visual acuity of 20/40 or better, without clinical evidence of foveal pathology between the ages of 13 and 97 years. 390 eyes were divided into 9 groups representing each decade of life between 2nd and 10th decade of life (31, 59, 30, 39, 59, 79, 49, 35, and 9 eyes for each decade). Foveal thickness maps were analyzed using several measurements: (1) Retinal thickness around the fovea at 50 micron consecutive intervals, (2) Parafoveal maximum retinal thickness at two points lateral to the central foveal depression, (3) The distance between two points of maximum retinal thickness, (4) Maximal foveal slope at two intervals lateral to the central foveal depression, and (5) Central length of foveal depression. The mathematical analog of the foveal configuration was analyzed using the automated symbolic regression software Eureqa (version 0.99.5) and the equation to describe the mathematical relationship in a 0.085 fit was derived for normal foveas according to age. A unique mathematical equation representing the mathematical analog of the foveal anatomy was derived for every decade of life, between 10 and 100 years.
Results:
The mathematical regression function for normal fovea followed a first order sine curve of level 12 complexity for the second decade of life. The mathematical regression function became significantly more complex with aging, up to a level 29 complexity for 0.085 fit. Young foveas had higher symmetry (0.93±0.2) along the midline whereas aged foveas had significantly less symmetry (0.61±1.5, P<0.01) along the midline and significantly steeper maximal slopes (15.3±0.8, P<0.01).
Conclusions:
The normal foveal anatomical configuration changes with age. Normal aged foveas are less symmetric, and have steeper slopes. The ability to differentiate between normal foveal aging and pathological/sick foveas by using SD-OCT scans may allow early diagnosis, follow up and better management of the aging population.
Keywords: 552 imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) •
550 imaging/image analysis: clinical •
585 macula/fovea