title: Validation of Smartphone Based Retinal Photography for Diabetic Retinopathy Screening.
abstract: OBJECTIVE
  To evaluate the sensitivity and specificity of "fundus on phone' (FOP) camera, a smartphone based retinal imaging system, as a screening tool for diabetic retinopathy (DR) detection and DR severity in comparison with 7-standard field digital retinal photography.
  
  
  METHODS
  Single-site, prospective, comparative, instrument validation study.
  
  
  METHODS
  301 patients (602 eyes) with type 2 diabetes underwent standard seven-field digital fundus photography with both Carl Zeiss fundus camera and indigenous FOP at a tertiary care diabetes centre in South India. Grading of DR was performed by two independent retina specialists using modified Early Treatment of Diabetic Retinopathy Study grading system. Sight threatening DR (STDR) was defined by the presence of proliferative DR(PDR) or diabetic macular edema. The sensitivity, specificity and image quality were assessed.
  
  
  RESULTS
  The mean age of the participants was 53.5 ±9.6 years and mean duration of diabetes 12.5±7.3 years. The Zeiss camera showed that 43.9% had non-proliferative DR(NPDR) and 15.3% had PDR while the FOP camera showed that 40.2% had NPDR and 15.3% had PDR. The sensitivity and specificity for detecting any DR by FOP was 92.7% (95%CI 87.8-96.1) and 98.4% (95%CI 94.3-99.8) respectively and the kappa (ĸ) agreement was 0.90 (95%CI-0.85-0.95 p<0.001) while for STDR, the sensitivity was 87.9% (95%CI 83.2-92.9), specificity 94.9% (95%CI 89.7-98.2) and ĸ agreement was 0.80 (95%CI 0.71-0.89 p<0.001), compared to conventional photography.
  
  
  CONCLUSIONS
  Retinal photography using FOP camera is effective for screening and diagnosis of DR and STDR with high sensitivity and specificity and has substantial agreement with conventional retinal photography.
authors.affiliation: Madras Diabetes Research Foundation & Dr.Mohan's Diabetes Specialities Centre, WHO Collaborating Centre for Non-communicable Diseases Prevention and Control, IDF Centre of Education, Gopalapuram, Chennai, India.
authors.forename: Ramachandran
authors.initials: R
authors.lastname: Rajalakshmi
authors.affiliation: Madras Diabetes Research Foundation & Dr.Mohan's Diabetes Specialities Centre, WHO Collaborating Centre for Non-communicable Diseases Prevention and Control, IDF Centre of Education, Gopalapuram, Chennai, India.
authors.forename: Subramanian
authors.initials: S
authors.lastname: Arulmalar
authors.affiliation: Madras Diabetes Research Foundation & Dr.Mohan's Diabetes Specialities Centre, WHO Collaborating Centre for Non-communicable Diseases Prevention and Control, IDF Centre of Education, Gopalapuram, Chennai, India.
authors.forename: Manoharan
authors.initials: M
authors.lastname: Usha
authors.affiliation: Madras Diabetes Research Foundation & Dr.Mohan's Diabetes Specialities Centre, WHO Collaborating Centre for Non-communicable Diseases Prevention and Control, IDF Centre of Education, Gopalapuram, Chennai, India.
authors.forename: Vijayaraghavan
authors.initials: V
authors.lastname: Prathiba
authors.affiliation: Madras Diabetes Research Foundation & Dr.Mohan's Diabetes Specialities Centre, WHO Collaborating Centre for Non-communicable Diseases Prevention and Control, IDF Centre of Education, Gopalapuram, Chennai, India.
authors.forename: Khaji Syed
authors.initials: KS
authors.lastname: Kareemuddin
authors.affiliation: Madras Diabetes Research Foundation & Dr.Mohan's Diabetes Specialities Centre, WHO Collaborating Centre for Non-communicable Diseases Prevention and Control, IDF Centre of Education, Gopalapuram, Chennai, India.
authors.forename: Ranjit Mohan
authors.initials: RM
authors.lastname: Anjana
authors.affiliation: Madras Diabetes Research Foundation & Dr.Mohan's Diabetes Specialities Centre, WHO Collaborating Centre for Non-communicable Diseases Prevention and Control, IDF Centre of Education, Gopalapuram, Chennai, India.
authors.forename: Viswanathan
authors.initials: V
authors.lastname: Mohan
mesh_terms: D000328:Adult; D000368:Aged; D003930:Diabetic Retinopathy / Q000175:diagnosis* / Q000453:epidemiology*; D005260:Female; D006801:Humans; D008297:Male; D008403:Mass Screening; D008875:Middle Aged; D019721:Ophthalmoscopes; D010781:Photography; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D000068997:Smartphone; D055815:Young Adult