Systematic screening for diabetic retinopathy with a digital fundus camera following pupillary dilatation in a university diabetes department

Correlation between Diabetic Retinopathy and Diabetic Peripheral Neuropathy in Patients with Type II Diabetes Mellitus

Background and Objectives:

The two most common complications of diabetes mellitus are retinopathy and neuropathy which are dealt by two different medical departments. Early detection and management are therefore necessary to prevent progression of these two diseases and will give a knowledgeable idea regarding the both. Thus, this study was done to know the association of diabetic peripheral neuropathy and diabetic retinopathy.

Methods:

This was a cross sectional study comprised of 200 cases of type 2 diabetes mellitus selected from the ophthalmology department and referred cases from other departments. A thorough history and examination was done in both departments, that is, complete ophthalmic and neurological examination respectively. Relevant investigations, if needed, were done and diabetic retinopathy was classified according to ETDRS classification.

Results:

Of the 200 patients having type 2 diabetes for more than 5 years, 28% of cases had diabetic retinopathy and 59% of cases had peripheral neuropathy. Peripheral neuropathy was twice more common than retinopathy. 33.1% had retinopathy and 65.46% had peripheral neuropathy among the uncontrolled diabetics. The prevalence of retinopathy increased 1.3 times in patients with neuropathy (16%) than in patients without peripheral neuropathy (12%).

Conclusion:

As there was higher incidence of peripheral neuropathy, it is important as ophthalmologists to look for peripheral neuropathy in diabetics which will help in reducing diabetes-related morbidities.

The cost-effectiveness of three screening alternatives for people with diabetes with no or early diabetic retinopathy

OBJECTIVE

To determine whether biennial eye evaluation or telemedicine screening are cost-effective alternatives to current recommendations for the estimated 10 million people aged 30-84 with diabetes but no or minimal diabetic retinopathy.

DATA SOURCES

United Kingdom Prospective Diabetes Study, National Health and Nutrition Examination Survey, American Academy of Ophthalmology Preferred Practice Patterns, Medicare Payment Schedule.

STUDY DESIGN

Cost-effectiveness Monte Carlo simulation.

DATA COLLECTION/EXTRACTION METHODS

Literature review, analysis of existing surveys.

PRINCIPAL FINDINGS

Biennial eye evaluation was the most cost-effective treatment option when the ability to detect other eye conditions was included in the model. Telemedicine was most cost-effective when other eye conditions were not considered or when telemedicine was assumed to detect refractive error. The current annual eye evaluation recommendation was costly compared with either treatment alternative. Self-referral was most cost-effective up to a willingness to pay (WTP) of U.S.$37,600, with either biennial or annual evaluation most cost-effective at higher WTP levels.

CONCLUSIONS

Annual eye evaluations are costly and add little benefit compared with either plausible alternative. More research on the ability of telemedicine to detect other eye conditions is needed to determine whether it is more cost-effective than biennial eye evaluation.

No loss of chance of diabetic retinopathy screening by endocrinologists with a digital fundus camera

OBJECTIVE

To compare the efficacy of the diabetic retinopathy (DR) screening with digital camera by endocrinologists with that by specialist and resident ophthalmologists in terms of sensitivity, specificity, and level of "loss of chance."

RESEARCH DESIGN AND METHODS

In a cross-sectional study, 500 adult diabetic patients (1,000 eyes) underwent three-field retinal photography with a digital fundus camera following pupillary dilatation. Five endocrinologists and two ophthalmology residents underwent 40 h of training on screening and grading of DR and detection of associated retinal findings. A κ test compared the accuracy of endocrinologist and ophthalmology resident screening with that performed by experienced ophthalmologists. Screening efficiency of endocrinologists was evaluated in terms of "loss of chance," i.e., missed diagnoses that required ophthalmologist referrals.

RESULTS

The mean weighted κ of DR screening performed by endocronologists was similar to that of ophthalmology residents (0.65 vs. 0.73). Out of 456 DR eyes, both endocrinologists and ophthalmology residents misdiagnosed only stage 1 DR (36 and 14, respectively), which did not require ophthalmologist referral. There were no significant differences between endocrinologists and ophthalmology residents in terms of diabetic maculopathy and incidental findings except for papillary cupping and choroidal lesions, which were not the main purpose of the study or of the training.

CONCLUSIONS

The endocrinologist with specific training for DR detection using a three-field digital fundus camera with pupillary dilatation can perform a reliable DR screening without any loss of chance for the patients when compared with identical evaluation performed by experienced ophthalmologists.

Systematic review of the diagnostic accuracy of the single, two and three field digital retinal photography for screening diabetic retinopathy

BACKGROUND

Regular eye examinations are important to aid in early detection of diabetic retinopathy. Screening methods include ophthalmoscopy, retinal photography and variations of both. Digital retinal photography (DRP) is being increasingly adopted. The gold standard is to photograph seven visual fields, in practice, however, fewer fields such as single, two or three fields are used, to reduce cost and time. There is no existing review comparing the diagnostic accuracy of the single, two and three-field DRP.

OBJECTIVES

To perform a systematic review of the diagnostic accuracy of the single, two and three field DRP for screening diabetic retinopathy.

INCLUSION CRITERIA

All patients with diabetes mellitus who attended an eye screening were included. Studies which include digital retinal imaging techniques that capture single, two or three visual images were considered.To be included, studies must have compared the technique to a reference standard, either the seven-field stereoscopic fundus photography (7SF) or indirect ophthalmoscopy.

TYPES OF OUTCOMES

The main outcomes were sensitivity and specificity of the screening technique.

SEARCH STRATEGY

Search was carried out, for the time period 1985 to December 2008, for full text papers and conference abstracts.

METHODOLOGICAL QUALITY

Methodological quality of included studies was assessed by two reviewers using an adapted version of the critical appraisal tool for diagnostic studies developed by the Critical Appraisal Skills Programme at the Public Health Resource Unit.

DATA COLLECTION

Data from included studies were extracted using a modified JBI data extraction tool.

DATA SYNTHESIS

Studies were grouped by the reference standard used and summarised using tabular and narrative formats.

RESULTS

Twenty-two primary studies met the review criteria. Fifteen studies used a single field, five applied two-field and seven applied three-field. There was great heterogeneity among the studies. Using 7SF as a reference standard, the sensitivity (for detecting any retinopathy) of the single, two and three fields ranged from: 66%-87%, 86%-98%, and 66%-98%. For indirect ophthalmoscopy, sensitivity ranged from 38%-100%, 83%-97%, and 90%-97%. The corresponding specificity for 7SF was 45%-96%, 78%-95%, 72%-86%; for indirect ophthalmoscopy was 47%-100%, 79%-100%, 90%-98%. Five studies comparing more than one field type had a general trend of higher sensitivity and lower specificity with increasing number of fields. Pupil dilation led to a lower proportion of ungradeable images.

CONCLUSIONS

The review findings are limited by the heterogeneity between studies and the number of studies comparing more than one screening type. Evidence for the optimal number of screening fields is not conclusive.

IMPLICATIONS FOR PRACTICE

Until further research is available for stronger comparisons to be made, single field DRP would be the option requiring less time and lower costs. Dilation should be applied to reduce ungradeable images. Older age, smaller pupil size, and presence of cataract are associated with ungradeable images.

IMPLICATIONS FOR RESEARCH

There is a strong recommendation for field specialists to achieve consensus on DRP methods including a standard scale for grading diabetic retinopathy and common threshold for referrable retinopathy. Future studies should consider following the Standards for Reporting of Diagnostic Accuracy (STARD). A prospective study comparing the single, two and three fields, with and without dilation will provide the required evidence for optimal number of fields.