Comparison of broadband and monochromatic photopic negative response in eyes of patients with diabetes with no diabetic retinopathy and different stages of diabetic retinopathy

Purpose:

To evaluate the change in broadband (W/W), red on blue (R/B), and blue on yellow (B/Y) photopic negative response (PhNR) in patients with diabetes mellitus with no diabetic retinopathy (no DR) and different stages of DR and compare it with age-matched controls. This study was performed to provide a single PhNR protocol that can be used for early diagnosis of DR.

Methods:

It was a cross-sectional case-control study done in a hospital setup. Patients with diabetes with no DR and different stages of DR with no other associated ocular pathologies were included. Age-matched controls with no retinal pathologies were also included for comparison. All subjects underwent detailed ophthalmic examination and W/W, R/B, and B/Y electroretinography. Fifty control eyes and 52 treatment naïve eyes of 52 patients with diabetes [no DR = 11, mild nonproliferative diabetic retinopathy (NPDR) =11, moderate NPDR = 10, severe NPDR = 9, and proliferative DR = 11] were included in the study.

Results:

On comparing the ERG responses in patients with diabetes and age-matched controls, a significant reduction (P < 0.05) was noted in the amplitudes of a-wave (39.78 ± 11.34 μV vs. 67.28 ± 12.88 μV), b-wave (116.25 ± 45.25 vs. 134.39 ± 28.78 μV), W/W PhNR (33.86 ± 17.33 vs. 67.18 ± 15.99 μV), R/B PhNR (28.77 ± 15.85 vs. 53.48 ± 14.15 μV), and B/Y PhNR (55.04 ± 32.63 vs. 104.79 ± 24.37 μV). Posthoc analysis revealed that all the eyes in the diabetic group, including those with no DR, had a significantly reduced PhNR amplitude (P < 0.05) when compared with controls. PhNR was found to reduce in amplitude with increasing severity of DR (P < 0.05), with more significance in B/Y. Receiver operating characteristic showed highest area under the curve in B/Y PhNR (94%, P < 0.001), with maximum sensitivity and specificity of 88% and 87%, respectively.

Conclusion:

Changes in the amplitude and implicit time of ERG can reflect the severity of DR. PhNR amplitudes, especially B/Y PhNR, appear to be significantly reduced even in eyes with no DR.

Role of a mydriasis-free, full-field flicker ERG device in the detection of diabetic retinopathy

PURPOSE

To determine if the RETeval system can be used for the screening of diabetic retinopathy (DR) to provide early diagnosis.

METHODS

The subjects were 42 diabetic patients selectively recruited by examination of their medical records to have varying severities of DR. The severity of DR was classified into four groups according to the International Clinical Diabetic Retinopathy Disease Severity Scale. Full-field electroretinograms (ERG) without mydriasis were obtained by the DR assessment protocol of the RETeval system. Macular retinal nerve fiber layer (RNFL) thickness was measured by optical coherence tomography. We compared the DR assessment protocol results and the macular RNFL thickness among four groups. Moreover, an analysis was conducted on whether there was any correlation among the DR assessment protocol results, duration of diabetes mellitus, and RNFL thickness individually for each group of patients.

RESULTS

The mean ages and mean duration of diabetes mellitus of the four groups were similar. The DR assessment protocol results in the moderate-severe nonproliferative DR, and proliferative DR groups were significantly higher than those in the other groups (p < 0.001). The mean macular RNFL thickness was similar in all groups. No significant correlation was found between the DR assessment protocol results and duration of DM and the RNFL thickness.

CONCLUSIONS

Our results suggest that the RETeval full-field ERG system can be used as an adjunctive tool for the mass screening of DR, while macular RNFL thickness would not be useful.

The effect of cilostazol on electrophysiologic changes in non-proliferative diabetic retinopathy patients

PURPOSE

To evaluate the effects of cilostazol, an antiplatelet and vasodilation agent, on the retinal function of patients with non-proliferative diabetic retinopathy (NPDR) using a full-field electroretinogram (ffERG).

METHODS

A total of 20 eyes from 20 patients were enrolled as the cilostazol-treated group, and 16 eyes from 16 patients were enrolled as the control group to assess the functional effects of cilostazol. Ophthalmologic examinations including fundus fluorescein angiography (FFA), fundus color photography, optical coherence tomography (OCT), and ffERG responses were recorded at baseline and after 1 year of cilostazol treatment. The number of microaneurysms on FFA, the number of exudates on fundus photographs, and central macular thickness (CMT) on OCT were compared between the two groups. Recording of ffERG was also performed at baseline and repeated after 1 year of treatment. The mean implicit times and amplitudes of a- and b-waves in each ffERG response were analyzed to evaluate the retinal function.

RESULTS

CMT and the numbers of microaneurysms and exudates showed no significant change in the cilostazol-treated group. There was no significant change in ffERG parameters between baseline and 1 year after the treatment in each group. The mean changes in implicit times from the cilostazol-treated group were significantly less than in the control group in b-waves from dark-adapted 3 ERG (p = 0.017) and 10 ERG responses (p = 0.047). On the other hand, the mean changes in amplitudes were not significant after 1 year of cilostazol treatment, but there were slight increases in amplitudes of dark-adapted 0.01 ERG and 10 ERG in the cilostazol-treated group.

CONCLUSIONS

These results suggest that cilostazol administration could reduce the implicit times of ffERG in patients with NPDR. It may be beneficial to preserve the retinal function in the diabetic retina, and additional research with larger populations and extended duration are needed to clarify the efficacy and safety of cilostazol for these patients.

A novel device for accurate and efficient testing for vision-threatening diabetic retinopathy

AIMS

To evaluate the performance of the RETeval device, a handheld instrument using flicker electroretinography (ERG) and pupillography on undilated subjects with diabetes, to detect vision-threatening diabetic retinopathy (VTDR).

METHODS

Performance was measured using a cross-sectional, single armed, non-interventional, multi-site study with Early Treatment Diabetic Retinopathy Study 7-standard field, stereo, color fundus photography as the gold standard. The 468 subjects were randomized to a calibration phase (80%), whose ERG and pupillary waveforms were used to formulate an equation correlating with the presence of VTDR, and a validation phase (20%), used to independently validate that equation. The primary outcome was the prevalence-corrected area under the receiver operating characteristic (ROC) curve for the detection of VTDR.

RESULTS

The area under the ROC curve was 0.86 for VTDR. With a sensitivity of 83%, the specificity was 78% and the negative predictive value was 99%. The average testing time was 2.3 min.

CONCLUSIONS

With a VTDR prevalence similar to that in the U.S., the RETeval device will identify about 75% of the population as not having VTDR with 99% accuracy. The device is simple to use, does not require pupil dilation, and has a short testing time.