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 Table of Contents  
Year : 2020  |  Volume : 32  |  Issue : 3  |  Page : 278-283

Efficacy of trash to treasure retcam in diabetic retinopathy screening

1 Department of Comprehensive Ophthalmology, Dr. Chandrakanth Malabar Nethralaya, Kozhikode, Kerala, India
2 Department of Retina, Dr. Chandrakanth Malabar Nethralaya, Kozhikode, Kerala, India
3 Department of Cornea, Dr. Chandrakanth Malabar Nethralaya, Kozhikode, Kerala, India
4 Department of Glaucoma, Dr. Chandrakanth Malabar Nethralaya, Kozhikode, Kerala, India

Date of Submission17-May-2020
Date of Acceptance23-Jun-2020
Date of Web Publication23-Dec-2020

Correspondence Address:
Dr. Prithvi Chandrakanth
Chandradevi, Opp Super Petrol Pump, Behind QRS, Kannur Road, W. Naddakkavu, Kozhikode - 673 011, Kerala
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/kjo.kjo_60_20

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Background: Diabetes mellitus is a global burden and its prevalence has always been on an increase and screening is the only method by which early diagnosis and treatment can be achieved. The current screening tools are expensive, heavy and immovable. Aims and Objectives: To find out the efficacy in terms of sensitivity and specificity of the Trash To Treasure Retcam (T3 Retcam - An innovative, inexpensive, portable and light device) in comparison with direct ophthalmoscope and digital fundus camera (canon CF1). Materials and Methods: This was a hospital-based prospective study with a sample size of 80 patients calculated using Buderer's formula. The patients were ones who have diabetes for more than 5 years and have not more than NS-1 cataract status. They were dilated and examined using direct ophthalmoscope, digital fundus camera, and T3 Retcam. Each examination was carried out by three different consultants who were blinded to each other to reduce bias. Each of them was given a form in which they had to tick the particular finding as to yes or no according to its presence. A comparative analysis was done. Results: Sensitivity of the T3 Retcam was found to be 88.4% and 92% compared to Direct Ophthalmoscope and Canon funds camera, respectively. Specificity was found to be 100%. Conclusion: Trash To Treasure Retcam is a novel, inexpensive device made out of used material in the clinic/outpatient department. This device can help us detect diabetic retinopathy and can also be used as a major tool for screening in camps. It is comparable to the direct ophthalmoscope and digital cameras and yield good data for screening purposes.

Keywords: Carbon footprint, diabetic retinopathy screening, innovation, low-cost screening, smartphone ophthalmology

How to cite this article:
Chandrakanth P, Chandrakanth K S, Sheeja Vishwanathan A K, Nirupama R, Mathew T. Efficacy of trash to treasure retcam in diabetic retinopathy screening. Kerala J Ophthalmol 2020;32:278-83

How to cite this URL:
Chandrakanth P, Chandrakanth K S, Sheeja Vishwanathan A K, Nirupama R, Mathew T. Efficacy of trash to treasure retcam in diabetic retinopathy screening. Kerala J Ophthalmol [serial online] 2020 [cited 2022 Dec 3];32:278-83. Available from: http://www.kjophthal.com/text.asp?2020/32/3/278/304559

  Introduction Top

Diabetes mellitus (DM) has established itself as a global burden in the light of microvascular and macrovascular complication and its prevalence has always been in the increase.[1] It is expected to rise from 285 million in 2010 to 439 million in 2030 globally.[2],[3],[4],[5] Among this, around 35 million people have been diagnosed with diabetes in India. It is predicted to reach about 80 million by 2030.[3] Early detection and treatment of complications is imperative to reduce the morbidity caused by diabetes.[6] A well-known entity which comes with the complication of diabetes is diabetic retinopathy (DR). It is a potentially blinding disease in adults and is observed in both rural and urban settings in India.[7] The visual morbidity due to DR remains a significant health burden with 30% of them classified to have vision-threatening diabetic retinopathy.[5] The progression of the disease is diagnosed through different stages ranging from Very Mild Non-Proliferative diabetic retinopathy (VMNPDR) to Moderate Non-Proliferative diabetic retinopathy (MODNPDR) stages, which are largely asymptomatic, to severe NPDR and proliferative diabetic retinopathy stages, which are potentially blinding if left untreated.[8] Vision loss can also be caused due to diabetic macular edema which can occur in addition to any of the above stages. DR has a fairly long asymptomatic period during which it can be easily diagnosed by fundus examination and imaging; hence, early detection and timely treatment are effective in reducing the risk of vision loss.[9],[10],[11],[12] Dilated fundus examination using direct or indirect ophthalmoscopy by a trained ophthalmologist is ideal for screening DR.[13] Studies have suggested that retinal photography after dilatation is comparable to ophthalmoscopic examination for DR detection.[14],[15] Fundus images traditionally are obtained with expensive and bulky tabletop machines which are usually operated by trained technicians in hospitals/clinical settings. Smartphones with their built-in camera technology and the ease and versatility of use have led to many ophthalmologists raising interest in their use in medical ophthalmic imaging. The portability, connectivity, storage capability, and the use of them in teleophthalmology have made them an attractive device for obtaining high-quality retina photographs in remote health centers/clinics and also in communities which currently receive no or suboptimal eye care facilities due to sociocultural and/or geographical barriers.[16] Comprehensive eye examination must be carried out at least annually to assess the DR grade in all patients with DM. A large number of patients do not receive the recommended quality of ophthalmic care.[17] This could mainly be due to fact that in India, majority of the population (72%) live in the rural areas and majority of the ophthalmologists are based in the urban centers. The ophthalmologist-to-population ratio is 1:107,000.[18],[19],[20] The nonavailability and high cost of the conventional tabletop fundus cameras further limit the screening process of DR.[21],[22],[23] Hence, to exploit the potential versatility of smartphones in diabetic retinopathy screening, various smartphone fundus imaging devices have been designed.[24],[25],[26],[27],[28],[29],[30],[31],[32],[33] Trash To Treasure Retcam is a unique smartphone fundus imaging device which can be made by anyone in their hospital/clinic with just a used hand sanitizer bottle. This device couples a 20D lens with a smartphone in a stable and reliable manner and works on the principle of an indirect ophthalmoscope.[34]

The objective of this study was to evaluate the sensitivity and specificity of Trash To Treasure Retcam in diagnosing diabetic retinopathy and its usefulness in diabetic retinopathy screening.


To find out the efficacy in terms of sensitivity and specificity of the Trash To Treasure Retcam in comparison with direct ophthalmoscope and digital fundus camera (canon CF1).

  Materials and Methods Top

The study was done in the retina clinic of a tertiary eye hospital. It was a cross-sectional, hospital-based, comparative study. Study participants were the patients coming to the outpatient department (OPD) with DM. The sample size (n) was calculated using Buderer's formula based on sensitivity = z21−α/2 × SN × (1 − SN)/L2 × Prevalence

where n = required sample size, SN = anticipated sensitivity, SP = anticipated specificity, α = size of the critical region (1−α is the confidence level), z21−α/2 = standard normal deviate corresponding to the specified size of the critical region (α), and L = absolute precision desired on either side (half-width of the confidence interval) of sensitivity or specificity assuming 80% sensitivity, 5% allowable error, prevalence 15%, the minimum sample size was calculated as 20 patients.

Sample and sampling

Inclusion criteria

  1. Patients who are known diabetic for the past 5 years
  2. Age more than 18 years
  3. No contraindication to mydriasis
  4. No allergy to tropicamide.

Exclusion criteria

  1. All patients with cataract, corneal pathology, or any media opacities
  2. Ocular infection.

Sample selection

By random selection, patients attending the OPD retina clinic were selected. A maximum of two patients were selected per day who fulfilled the above-mentioned inclusion and exclusion criteria. If there were more than two patients who fulfilled the criteria, the first two consecutive patients were taken up for the study.

Data collection tool/instrumentation

  1. Pro forma
  2. Details of measurement.

Informed and written consent were obtained. Detailed history of patients regarding name, age, sex, occupation, and address; drug history; any history of trauma or inflammation, presenting symptom, duration, and associated conditions; and medical history were recorded. Ocular examination was done to rule out any abnormality in the lids, conjunctiva, cornea, anterior chamber depth, iris, pupil, and lens. Gross systemic examination was done. Visual acuity and refraction were assessed using an illuminated Snellen's chart, and the WHO classification system was used to classify the best-corrected visual acuity and near vision with Jaegger's chart. Ocular examination was done to rule out any abnormality in the lids, conjunctiva, cornea, anterior chamber depth, iris, pupil, and lens with a torchlight. Slit-lamp biomicsroscopic examination was carried out to confirm the torchlight findings and to rule out conjunctival pathology, corneal pathology also anterior chamber dept. Dilatation of the eye was done by instilling eyedrop Itrop plus (tropicamide + phenylphrine) in the lower cul-de-sac. Stereoscopic fundus examination was done by slit lamp and + 90D lens or a ophthalmoscope and diagnosed by a senior consultant ophthalmologist. The patients were then taken up for fundus photography in the Canon CF 1 and the T3 Retcam which were operated by two different consultant ophthalmologists who were blinded to each other and were asked to tick the observational findings. Grading of diabetic retinopathy was done with Early Treatment Diabetic Retinopathy Study (ETDRS) grading system [Figure 1] and [Figure 2].
Figure 1: Images taken from Canon fundus camera (a-d). Images taken from the Trash To Treasure Retcam (e-h)

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Figure 2: Images taken from Canon fundus camera (a-d). Images taken from the Trash To Treasure Retcam (e-h)

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Statistical analysis

Details of data entry and storage/software: The data were entered and analyzed by SPSS version 24 (IBM, Armonk, New York, United States). The data were expressed as sensitivity, specificity, diagnostic accuracy, frequency, and percentages.

  Results Top

Demographics and baseline characteristics

We included 80 eyes in this study. There statistics shows that 23 eyes (28.75%) were found to be normal and 57 eyes (71.25%) had Diabetic retinopathy findings [Table 1]. Subjects in the age group of 51-60 years (51.25%) had the maximum number of patients with Diabetes Mellitus (DM) followed by those falling the age group of 41-50 years. Age group with the least subjects who had DM were those falling in 20-30 years [Table 2]. There were a total of 37 males (46.25%) and 43 Females (53.75%) included in this study [Table 3]. Direct Ophthalmoscope being the standard fundus examination technique, was used to examine each eye and with sign obtained were grouped into the Early Treatment Diabetic Retinopathy Study (ETDRS) classification. 23 eyes did not have any DR changes, 7 eye were diagnosed to have Very Mild Non proliferative Diabetic Retinopathy(VMNPDR), 14 were Mild Non Proliferative Diabetic Retinopathy (MNPDR), 8 were Moderate Non Proliferative Diabetic Retinopathy(MODNPDR), 2 were Severe Non Proliferative Diabetic Retinopathy(SNPDR), 6 were Very Severe Non Proliferative Diabetic Retinopathy, 1 was diagnosed as Early Proliferative Diabetic Retinopathy (EPDR), 7 were High Risk Non Proliferative Diabetic Retinopathy(HRPDR), 12 eyes had laser marks and were grouped under Post-Pan Retinal Photocoagulation Status(Post-PRP) and 16 were diagnosed to have Clinically Significant Macular Edema(CSME) [Table 4] and [Table 5].
Table 1: Distribution of number of eyes

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Table 2: Age group

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Table 3: Gender distribution

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Table 4: Distribution of diabetic retinopathy changes

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Table 5: ETDRS classification statistics

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Sensitivity and Specificity

After evaluating the eyes with both Canon Fundus Camera and Trash To Treasure Retcam the findings and diagnosis were compared with that of the Direct Ophthalmoscope and sensitivity and specificity were derived. The T3 Retcam had a sensitivity of 88.4% (95% Confidence Interval (CI) : 76.2 – 100) and a Specificity of 100% when compared to Direct Ophthalmoscopy, Also a sensitivity of 92% (95% Confidence Interval (CI) : 81.3 - 100) and a Specificity of 100% when compared to The Canon CF1 Fundus Camera. The Positive Predictive Value, Negative Predictive Value, Kappa Coefficient and P Value were also calculated [Table 6].
Table 6: Comparison and statistics of diabetic retinopathy diagnosis

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  Discussion Top

Diabetic patients were selected and examinations and photographs were taken according to the method explained above. Demographic details show that there was a higher percentage of females (53.75) than males in this study and those with normal fundus comprised up to 28%. Diabetic retinopathy changes were more in individuals in the age group of 51–60 years. The diagnosis of Normal retina and Very Mild Non- Proliferative Diabetic Retinopathy(VMNPDR) depends upon the presence of the sign – Micro aneurysm. This sign was recognized in 57 cases through Direct Ophthalmoscopy and 50 cases were detected in both Canon CF1 and Trash To Treasure Retcam and hence was the limiting factor for these instrument as the misdiagnosed the VMNPDR cases as Normal cases. The number of cases missed by Canon cf1 was 2 and those with T3R was 6. All other diabetic retinopathy findings were detectable in both the devices. When each of the device was compared with each other, the CCF1 had a sensitivity of 96.2% compared to the DO and a specificity of 100%. The T3R had a sensitivity of 88.4% and a specificity of 100% with the DO. The T3R had a sensitivity of 92% with that of CCF1 and a specificity of 100%. When taking the statistics of the ETDRS classification, we can see that the T3R has misdiagnosed 6 patients as normal whereas they were diagnosed to have very mild NPDR by DO, which means that the T3R is not sensitive to the minute findings such as the microaneurysms and hence become the limitation of the T3R as it cannot pick the microaneurysms. The Trash To Treasure Retcam has been able to pick up larger findings/signs (Dot and Blot haemorrhage, hard exudate, soft exudate, superficial haemorrhage, IRMA, NVE, NVD, Tractional bands, Laser marks, CSME) which pose a threat to the vision. Although it misdiagnosed cases of VMNPDR group it has been able to diagnose sight threatening cases. Using Colour retinal photography has an advantage of being faster in diagnosing diabetic retinopathy with respect to easier acquisition, storage and transfer of retinal images. Studies have shown that Smartphone acquired images of diabetic retinopathy are comparable to those images taken by fundus cameras.[35],[36],[37],[38] The Trash To Treasure Retcam can be valuable as a diagnostic tool with added benefit of carrying it anywhere and able to store and also share the picture. It can be used for tele ophthalmology and also for bedridden patient as well as for Retinopathy of Prematurity (ROP).

  Conclusions Top

T3 Retcam is an inexpensive, quick, convenient, and portable device, with high sensitivity, specificity, and diagnostic accuracy for diabetic screening and helps reduce morbidity of patients who are at a high risk of vision loss especially in rural and camp settings.


  • Mrs. Sree Devi Chandrakanth, Director, Dr. Chandrakanth Malabar Nethralaya, Kozhikode
  • Miss. Grishma Chandrakanth, Director, Dr. Chandrakanth Malabar Nethralaya, Kozhikode.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

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  [Figure 1], [Figure 2]

  [Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6]


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