Ophthalmic Research – Malini BAKTHAVATCHALAM




  • BS, Optometry, Birla Institute of Technology and Science
  • Fellowship, Low vision, Sankara Nethralaya-Chennai

Research Areas:

  1. Foveal Avascular Zone (FAZ) with Optical Coherence Tomography Angiography (OCTA) in predicting treatment response of anti-vascular endothelial growth factor (anti-VEGF) therapy in diabetic macular edema (DME)
  2. Characterization of Choroidal Morphological Changes in Exudative Age-Related Macular Degeneration (AMD), Polypoidal Choroidal Vasculopathy and Central Serous Chorioretinopathy.



  1. Lai F H.P, Ng DS, Bakthavatsalam M, Chan V CK, Young AL, Luk F OJ, Tsang C W, Brelén ME. A Multicenter Study on the Long-term Outcomes of Half-dose Photodynamic Therapy in Chronic Central Serous Chorioretinopathy. Am J Ophthalmol 2016;170:91–99.


Research Highlights:

(1) Documentation of Foveal Avascular zone with the help of Optical coherence Tomography (OCTA)

Optical Coherence Tomography Angiography (OCTA) is the novel imaging technology that can provide high resolution three dimensional images of the perfused vessel without the use of injectable dyes. It allows a reliable and automated assessment of the Foveal Avascular Zone (FAZ). Diabetic Macular Edema is most common cause of visual impairment in the working age population. The Foveal Avascular Zone (FAZ) is the capillary free area at the macula and the size of FAZ is considered an indicator of the degree of ischemia in Diabetic Retinopathy (DR) patients.


Research-Highlight-Malini-BAKTHAVATCHALAM-1Figure 1. The image of the patient is taken from OCTA machine and the size of FAZ is calculated using semi-automated Matlab program.


Our future studies will focus on investigating the vascular structural changes in Vein occlusion patients including Branch Retinal Vein Occlusion (BRVO) and Central Retinal Vein Occlusion (CRVO) using OCTA.


(2) To characterize choroidal vascularity in neovascular AMD and PCV

The phenotypes of exudative AMD in Asians are heterogeneous and the treatment outcomes are variable. A thick choroid has been observed in polypoidal Choroidal Vasculopathy (PCV), a presumed subtype of exudative Age-related Macular Degeneration (AMD) with high prevalence among Asians. Nevertheless, using merely the choroidal thickness alone to distinguish the phenotypes in exudative AMD can be inconsistent. With the advent of high speed and deep penetrating OCT, we are able to image the near histological resolution of the choroidal morphology in 3 dimensions. In the enface view, we are able to visualize pathological changes in choroidal vessels. Binarised images allow quantified analysis of the choroidal vascularity in vivo.



Figure 2. (Left) En face OCT image of the outer choroid in a 74 yeear-old man. (Right) Abnormally dilated choroidal vessels that are displaced peripheral to an atrophic (white) region in exudative AMD.



Figure 3. (Left) Swept source OCT reveals the entire cross-section of the choroidal layer. (Right) Binarisation of cross-sectional OCT for evaluation of choroidal vascularity