FP769 : Smart Way of Diabetic Retinopathy (DR) Screening – A Comparative Study.

Dr. Vinaya Kumar Konana, K16522, Dr. Mishra Divyansh Kailashcandra, Dr. Rajesh Ramanjulu, Dr.Mahesh Shanmugam P

Introduction

Diabetic eye disease (DED) secondary to diabetes mellitus (DM) is the most common cause for blindness during working age worldwide¹. However, due to lack of medical care the disease is under-diagnosed in developing countries. Up to two thirds of diabetic patients are undiagnosed². In rural areas ofSouth-India the prevalence is up to 10%^{2, 3}. Out of these, 18 – 34% has diabetic eye disease (DED) on initial diabetes diagnosis^4-9. 74% of India’s population live in rural areas with limited access to medical care¹⁰. DED will affect almost every diabetes patient within 15 years following diagnosis¹¹. Blindness caused by diabetes, however, can be prevented in nearly all cases by an early diagnosis, optimization of risk factors and early management of ocular complications^{1, 7, and 12}. Access to health care and lack of sophisticated instruments makes diabetic retinopathy screening a challenge in remote areas. Using smartphone based as a direct ophthalmoscope for diabetic screening in such remote areas would make eye care accessible and hence preventing blindness related to diabetes.Many smart phone based fundoscopy devises are available in the market. They are PEEK retina, D Eye, Paxos and DIY.  So far there is no comparative study between these devices.

Aim

In this study we compare efficacy of two smart phone based direct ophthalmoscope devices [D EYE and do it yourself solution (DIY)] with a non mydriatic fundus camera ( 3netra)

Material and methods

This is prospective cross sectional study conducted at a tertiary eye care hospital. In this study 200 patients with diabetes were screened in different outreach camps at both rural and urban areas. Aim of this study was to compare two different smart phone based direct ophthalmoscope devices (D Eye and DIY) for diabetic retinopathy screening in South-India.

We included diabetic patients who attend screening camp. We excluded patients with shallow anterior segment, severe media opacities and patients who are allergic to dilating eye drops.Screening camps were conducted at both rural and urban areas.

After dilatation with 5% phenylephrine and 0.8% tropicamide fundus was examined with D Eye, DIY and 3netra. Videos from smart phone based devices were acquired from the optic nerve head, the macula and the four arcades and 7 field photos was taken with 3netra. For the smartphone-based examination the following acquisition protocol will be applied: optic nerve head (ONH), lower temporal arcade centrifugally, macula, upper temporal arcade from periphery to ONH, lower nasal arcade centrifugally, upper nasal arcade from periphery to ONH. DED will be graded according to the International Clinical Diabetic Retinopathy Disease and Macular Edema Disease Severity Scale proposed by the Global Diabetic Retinopathy Project Group. The screening of patients was done by trained optometrists and doctors. The images acquired by each device were assessed for presence of diabetic retinopathy, field of view, image quality consisting of sharpness, reflexes, illumination. Grading scale was devised for each parameter is described in table 1. The images were assessed for sensitivity and specificity for ability to identify diabetic retinopathy and diabetic maculopathy and to assess the need for referral. Field of view was assessed using ImageJ software.The images were assessed by two qualified observers. Inter observer variability was also calculated. 3netra was considered as the gold standard device and images from D Eye and DIY were compared to the images from 3netra.

Informed consent was obtained from all the participants and institutional ethical and scientific committee approval was obtained prior to commencement of the study.

Results

Two hundred patients were included in the study. Of the 200 patients 40 patients had diabetic retinopathy. Of the 40 % (n= 16) of cases with diabetic retinopathy needed referral to higher center for further treatment.

Reflex artifact seen in D Eye- grade 0 in 39% and grade 1 in 59% , whereas in DIY it was grade 0 in 16%, grade 1 in 16%, grade 2 in 41% and grade 3 in 25% of the eyes.

Illumination in D-Eye was grade 1 in 61.5%, grade 2 in 38.5%, whereas in DIY it was 58% in grade 1 and 42% in grade 2 (p>0.05).

Sharpness of image in D-Eye was grade1 in 7.6%, grade 2 in 76.92% and grade 3 in 15.38%, in DIY grade 1 in 7.6%, grade 2 in 53.84% and grade 3 in 30.7%.

There was good agreement between grading done by the two observers.

Discussion

Screening of diabetic patients is a very effective tool in preventing vision threatening complications. Mobile phone being ubiquitous can be a cost effective and a portable alternative to conventional fundus camera.

Out of 200 patients, diabetic retinopathy was detected in 40 patients, this correlates well with the known prevalence of diabetic retinopathy (20%) in patients with diabetes.  Diabetes being a posterior pole disease can be easily identified by direct ophthalmoscope.

In this study we found that sharpness of the image was better with DIY when compared to D-Eye.Illumination of the fundus with DIY was better when compared to D-Eye. The field of view was greater in DIY when compared to D-Eye.

Both smartphone based devices could identify diabetic retinopathy with same sensitivity as that of the gold standard device (3Netra). This proves that the two  smart phone based devices were effective in identifying the presence of diabetic retinopathy.

Reflexes seen while acquiring the video hampered the quality of image and hence hampered image grading in few cases more so in D-Eye when compared to DIY. These reflexes can be avoided to some extent by tilting the smartphone.

DIY from having better sharpness, illumination and field of view when compared to D-Eye. DIY is easy to assemble with an added advantage of being cost effective. DIY is approximately 150 times cheaper when compared to D-Eye. (The estimated cost of D-Eye is Rs 30000 and DIY is Rs 200)

Limitation of these smart phone devices are limited field of view, inability to image eyes with media opacity. Limitations of this study are small sample size and considering 3netra as gold standard instead of clinical examination.

To our knowledge ours is the first study which compares these two smartphone based direct ophthalmoscopes. Smartphone based devices can be a cost effective and a feasible screening tool for diabetic retinopathy.

Conclusion

Smart phone based direct ophthalmoscope devices are effective in screen patients with diabetic retinopathy. Both D eye and DIY were found to be effective in detection of diabetic retinopathy. DIY had better feel of view and less artifacts due to reflexes when compared  to D eye. D eye had better illumination when compared to DIY.

References

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Table 1: Grading scale for parameters assessed