title: Characteristics and quantification of vascular changes in macular telangiectasia type 2 on optical coherence tomography angiography.
abstract: BACKGROUND
  Macular telangiectasia type 2 (MacTel 2) is a bilateral idiopathic, rare neurodegenerative disease with alterations in the macular capillary network leading to vision loss and is the most common of three subtypes. Optical coherence tomography angiography (OCTA) is a non-invasive imaging modality which helps understand the complex pathological changes, and images the blood vessels across different layers based on their flow characteristics.
  
  
  METHODS
  A cross-sectional study was conducted on 56 eyes of Asian Indian eyes of 28 consecutive patients with MacTel 2 studied during a 3-month period in a tertiary eye care hospital of South India. Clinically diagnosed cases of MacTel 2 underwent fundus photography, spectral domain OCT and OCTA. Fluorescein angiography was performed only when clinically indicated. Mean capillary density was calculated using a MATLAB-based automated software. The images were thresholded and binarised to derive the mean value.
  
  
  RESULTS
  The mean age at presentation was 60±5.2, with a female preponderance of 71.42%. Vascular network on OCTA shows an increase in the intervascular spaces with progressive capillary rarefaction and abnormal capillary anastomosis. The outer retina and choroid were involved during the later stages and showed a prominent vascular network. The mean capillary density of the superficial and deep layers was 39.99% and 39.03% as against 45.18% and 44.21% in the controls, respectively. There was a statistically significant difference between the two groups (p<0.01). There is a positive and statistically significant correlation between the superficial and deep layers.
  
  
  CONCLUSIONS
  OCTA helps understand the pathology and disease progression better in MacTel 2.
authors.affiliation: Narayana Nethralaya Eye Hospital, Bangalore, India.
authors.forename: Lavanya
authors.initials: L
authors.lastname: Chidambara
authors.affiliation: Narayana Nethralaya Eye Hospital, Bangalore, India.
authors.forename: Santosh G K
authors.initials: SG
authors.lastname: Gadde
authors.affiliation: Narayana Nethralaya Eye Hospital, Bangalore, India.
authors.forename: Naresh Kumar
authors.initials: NK
authors.lastname: Yadav
authors.affiliation: Narayana Nethralaya Eye Hospital, Bangalore, India.
authors.forename: Chaitra
authors.initials: C
authors.lastname: Jayadev
authors.affiliation: Narayana Nethralaya Eye Hospital, Bangalore, India.
authors.forename: Devanshi
authors.initials: D
authors.lastname: Bhanushali
authors.affiliation: BMS College of Engineering, Bangalore, India.
authors.forename: Abhishek M
authors.initials: AM
authors.lastname: Appaji
authors.affiliation: Narayana Nethralaya Eye Hospital, Bangalore, India.
authors.forename: Mukunda
authors.initials: M
authors.lastname: Akkali
authors.affiliation: Narayana Nethralaya Eye Hospital, Bangalore, India.
authors.forename: Aruj
authors.initials: A
authors.lastname: Khurana
authors.affiliation: Narayana Nethralaya Eye Hospital, Bangalore, India.
authors.forename: Rohit
authors.initials: R
authors.lastname: Shetty
mesh_terms: D000328:Adult; D000368:Aged; D002196:Capillaries / Q000473:pathology*; D003430:Cross-Sectional Studies; D018450:Disease Progression; D005260:Female; D005451:Fluorescein Angiography / Q000379:methods*; D005500:Follow-Up Studies; D005654:Fundus Oculi; D006801:Humans; D008266:Macula Lutea / Q000098:blood supply* / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D012039:Regional Blood Flow; D058456:Retinal Telangiectasis / Q000175:diagnosis* / Q000503:physiopathology; D012171:Retinal Vessels / Q000000981:diagnostic imaging* / Q000503:physiopathology; D013997:Time Factors; D041623:Tomography, Optical Coherence / Q000379:methods*
keywords: Imaging; Macula; Retina