title: Retinal Neurodegeneration Associated With Peripheral Nerve Conduction and Autonomic Nerve Function in Diabetic Patients.
abstract: OBJECTIVE
  In this study, we evaluated the correlation of retinal thickness with peripheral nerve conduction and autonomic nerve function in diabetic patients.
  
  
  METHODS
  Cross-sectional study.
  
  
  METHODS
  Medical records of 160 patients (mean age, 63.61 ± 12.52 years) with diabetes without diabetic retinopathy or mild nonproliferative diabetic retinopathy (NPDR) were reviewed. The mean retinal thickness of the parafoveal area and ganglion cell/inner plexiform layer (GC-IPL) thickness in 6 macular regions were measured using optical coherence tomography. Peripheral nerve conduction studies were conducted on peroneal and posterior tibial motor nerves and the sural sensory nerve. Five cardiovascular autonomic function tests were performed. We classified patients into groups by severity of peripheral neuropathy and autonomic dysfunction and analyzed the correlations with mean retinal thickness.
  
  
  RESULTS
  The mean retinal thickness of the parafovea was 315.05 ± 12.70 μm and mean macular GC-IPL thickness was 79.89 ± 4.70 μm. Macular GC-IPL thickness showed significant correlation with peripheral nerve conduction (no peripheral neuropathy vs definite peripheral neuropathy: 82.0 ± 4.8 μm vs 75.2 ± 3.8 μm, P < .001). GC-IPL thickness decreased with severity of autonomic nerve dysfunction (no/mild dysfunction vs severe dysfunction: 81.2 ± 6.6 μm vs 77.6 ± 5.9 μm, P = .005). There was no significant correlation between the retinal thickness of the parafovea and electrodiagnostic tests.
  
  
  CONCLUSIONS
  The decrease of GC-IPL thickness was positively correlated with both peripheral nerve conduction and autonomic nerve function in diabetic patients who presented with no diabetic retinopathy or mild NPDR.
authors.affiliation: Department of Ophthalmology, Kyung Hee University Hospital, Kyung Hee University, Seoul, South Korea.
authors.forename: Kiyoung
authors.initials: K
authors.lastname: Kim
authors.affiliation: Department of Ophthalmology, Kyung Hee University Hospital, Kyung Hee University, Seoul, South Korea.
authors.forename: Seung-Young
authors.initials: SY
authors.lastname: Yu
authors.affiliation: Department of Ophthalmology, Kyung Hee University Hospital, Kyung Hee University, Seoul, South Korea.
authors.forename: Hyung Woo
authors.initials: HW
authors.lastname: Kwak
authors.affiliation: Department of Ophthalmology, Kyung Hee University Hospital, Kyung Hee University, Seoul, South Korea. Electronic address: eungyi@khu.ac.kr.
authors.forename: Eung Suk
authors.initials: ES
authors.lastname: Kim
mesh_terms: D000368:Aged; D003430:Cross-Sectional Studies; D003924:Diabetes Mellitus, Type 2 / Q000150:complications; D003929:Diabetic Neuropathies / Q000503:physiopathology*; D003930:Diabetic Retinopathy / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009410:Nerve Degeneration / Q000503:physiopathology; D009431:Neural Conduction / Q000502:physiology*; D010543:Peroneal Nerve / Q000502:physiology*; D012160:Retina / Q000000981:diagnostic imaging / Q000473:pathology*; D055351:Retinal Neurons / Q000473:pathology; D013497:Sural Nerve / Q000502:physiology*; D013979:Tibial Nerve / Q000502:physiology*; D041623:Tomography, Optical Coherence