Abstract
Purpose: :
To evaluate the efficacy of macular compared with wide field multifocal pupillary objective perimetry (mfPOP) stimuli in patients with type 1 (T1D) and type 2 (T2D) diabetes presenting with non-proliferative diabetic retinopathy (NPDR).
Methods: :
Fourteen individuals diagnosed with T1D (35.5 ± 11.32 years, 8 females, mean duration 22.5 ± 10.1 years), sixteen T2D (51.7 ± 13.5 years, 9 females, mean duration 10.7 ± 4.9 years) and 24 normal (55.8 ± 7.2 years , 13 females) subjects were recruited. Pupillary contraction amplitudes and time to peak responses to 2 multifocal stimulus protocols comprising of 44 stimulus regions per eye extending to either ±15° or ±30° were measured dichoptically. All protocols had a mean presentation interval of 4 s/region and a duration of 33 ms on each presentation. Cameras under infrared illumination monitored pupil responses. Linear models were fitted to contraction amplitudes and times to peak responses to determine the independent effects of disease. Area under receiver operator characteristic curves (AUCs) compared the diagnostic accuracy of macular and wide field mfPOP.
Results: :
Stimuli presented in the central ±15° achieved the largest mean amplitude deviations corrected for age for both T1D (-3.76 ± 0.24 dB, t = -15.7) and T2D (-2.02 ± 0.14 dB, t = -14.8). On average, time to peak responses were also more delayed with the macular mfPOP stimulus in T1D (49.11 ± 2.24 ms, t = 21.9) and T2D (21.25 ± 1.78 ms, t = 11.9) patients (all effects p < 5 x 10-32). In T2D macular mfPOP stimuli achieved the highest ROC area under the curve (AUC) of 1.00. In TD1 stimuli extending to ±30° were more diagnostic when a linear discriminant model incorporating contraction amplitude and time to peak deviations were considered.
Conclusions: :
This pilot study suggests that central retinal sensitivity loss may be more informative in NPDR and identifies the utility of mfPOP as a screening test for visual dysfunction in patients with T1D and T2D. Longitudinal studies evaluating whether mfPOP is a good predictor of diabetic retinopathy progression in noninsulin and insulin-dependent patients is warranted.
Keywords: diabetic retinopathy • perimetry • pupil