Diabetes Perimetry Protocols Shows Link Between Retinal Function, Tissue Damage

Multifocal pupillographic objective perimetry (mfPOP) can detect localized visual field dysfunction in patients with type 1 diabetes (T1D), according to a study published in BMC Ophthalmology. The research also found that the method can discriminate patients with diabetic retinopathy (DR) from those without. 

The pilot study included 25 patients with type 1 diabetes (age 41.8±12.1 years, 13 men, 12 women) with either no DR (n=13) or non-proliferative DR (n=12), and 23 age and gender-matched controls (age 39.7±12.9 years, 14 women, 9 men). The participants and controls were evaluated by mfPOP using 5 different stimulus methods differing in visual field eccentricity (central 30° and 60°), as well as color (blue, yellow or green test-stimuli presented on, respectively, a blue, yellow or red background), each assessing 44 test-locations per eye.   

In patients with T1D, 16 metabolic status and diabetes complications variables were examined. The study summarized these as 3 principal component analysis (PCA) factors. The researchers assessed DR severity by using Early Treatment of Diabetic Retinopathy Study (ETDRS) scores. They used area under the curve (AUC) from receiver operator characteristic analyses to quantify the diagnostic power of mfPOP response sensitivity and delay deviations for discriminating: 

1. Patients with T1D from controls.
2. Patients with T1D based on 3 levels of the identified PCA-factors from controls.
3. Patients with TID from those without non-proliferative DR.

The researchers found that the 2 largest PCA-factors characterizing patients with T1D were associated with metabolic variables (e.g. body mass index, HbA1c), and tissue-injury variables (e.g. serum creatinine, vibration perception). Linear models revealed that mfPOP per-region response delays were associated more with the metabolic PCA-factor and ETDRS scores than sensitivities.

Combined mfPOP amplitude and delay measures yielded AUCs of 90.4±8.9% for differentiating patients with T1D and DR from controls, and patients with T1D and DR from those without, 85.9±8.8%. The team notes that the yellow and green stimuli performed better compared with blue on most measures. 

In patients with T1D, mfPOP testing “was able to identify localized visual field functional abnormalities (retinal/neural reflex) in the absence or presence of mild DR,” report the researchers. “mfPOP responses were also associated with T1D metabolic status, but less so with early stages of non-ophthalmic diabetes complications.” 

Study limitations include failure to investigate repeatability, the relatively long duration of T1D (23.3-24.7 years), the sample size for each retinopathy severity and blood samples were not taken from controls.

Disclosure: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. This research was supported by multiple sources. Please see the original reference for a full list of disclosures. 

Reference

Sabeti F, Carle CF, Nolan CJ, et al. Multifocal pupillographic objective perimetry for assessment of early diabetic retinopathy and generalised diabetes-related tissue injury in persons with type 1 diabetes. BMC Ophthalmol. Published online April 13 2022. doi:10.1186/s12886-022-02382-2

This article originally appeared on Ophthalmology Advisor