A non-invasive and simple point measurement using a portable TD-OCT system was used to measure the leaf structure and attenuation coefficient of healthy and unhealthy leaves of a Citrofortunella Microcarpa plant. Assuming homogeneity within the layers, the attenuation coefficient was obtained by linear fitting the logarithm of the A-scan or depth profile of the leaf. The attenuation coefficients of the epidermal and palisade layers of the healthy leaves were 27.07/mm and 15.36/mm, respectively, and for the unhealthy leaves they were 21.82/mm and 8.01/mm, respectively. Comparing the A-scan profiles obtained for the healthy and unhealthy leaves, a mixing of the epidermal and palisade layers within the unhealthy leaves was observed. These observations and the decrease in the attenuation coefficients of the unhealthy leaves are indications of deterioration in the photosynthetic rate that enhances the growth and development of the plants which can provide early detection of sickness benefitting Filipino farmers.