{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,27]],"date-time":"2026-10-27T17:12:26Z","timestamp":1793121146618,"version":"4.5.0"},"reference-count":32,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2021,4,23]],"date-time":"2021-04-23T00:00:00Z","timestamp":1619136000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Endocrinol."],"abstract":"<jats:sec><jats:title>Aims<\/jats:title><jats:p>To establish the sequential changes by glycemic control in the mean thickness, volume and reflectance of the macular photoreceptor layers (MPRLs) and retinal pigment epithelium in patients with type 2 diabetes without diabetic retinopathy.<\/jats:p><\/jats:sec><jats:sec><jats:title>Methods<\/jats:title><jats:p>Thirty-one poorly controlled (HbA1c &amp;gt; 8.0%) patients with type 2 diabetes without diabetic retinopathy undergoing glycemic control and 39 control subjects with normal HbA1c levels (&amp;lt; 5.9%) underwent periodical full medical, neurological and ophthalmological examinations over 2 years. Glycemic variability was evaluated by standard deviation and coefficient of variation of monthly measured HbA1c levels and casual plasma glucose. 3D swept source-optical coherence tomography (OCT) and OCT-Explorer-generated enface thickness, volume and reflectance images for 9 subfields defined by Early Treatment Diabetic Retinopathy Study of 4 MPRLs {outer nuclear layer, ellipsoid zone, photoreceptor outer segment (PROS) and interdigitation zone} and retinal pigment epithelium were acquired every 3 months.<\/jats:p><\/jats:sec><jats:sec><jats:title>Results<\/jats:title><jats:p>Glycemic control sequentially restored the thickness and volume at 6, 4 and 5 subfields of outer nuclear layer, ellipsoid zone and PROS, respectively. The thickness and volume of outer nuclear layer were restored related to the decrease in HbA1c and casual plasma glucose levels, but not related to glycemic variability and neurological tests. The reflectance of MPRLs and retinal pigment epithelium in patients was marginally weaker than controls, and further decreased at 6 or 15 months during glycemic control. The reduction at 6 months coincided with high HbA1c levels.<\/jats:p><\/jats:sec><jats:sec><jats:title>Conclusion<\/jats:title><jats:p>Glycemic control sequentially restored the some MPRL thickness, especially of outer nuclear layer. In contrast, high glucose during glycemic control decreased reflectance and may lead to the development of diabetic retinopathy induced by glycemic control. The repeated OCT examinations can clarify the benefit and hazard of glycemic control to the diabetic retinopathy.<\/jats:p><\/jats:sec>","DOI":"10.3389\/fendo.2021.614161","type":"journal-article","created":{"date-parts":[[2021,4,23]],"date-time":"2021-04-23T06:42:10Z","timestamp":1619160130000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":9,"title":["The Impact of Glycemic Control on Retinal Photoreceptor Layers and Retinal Pigment Epithelium in Patients With Type 2 Diabetes Without Diabetic Retinopathy: A Follow-Up Study"],"prefix":"10.3389","volume":"12","author":[{"given":"Fukashi","family":"Ishibashi","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Aiko","family":"Kosaka","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mitra","family":"Tavakoli","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2021,4,23]]},"reference":[{"key":"B1","doi-asserted-by":"publisher","DOI":"10.1371\/journal.pone.0145628","article-title":"Enface thickness mapping and reflectance imaging of retinal layers in diabetic retinopathy","volume":"10","author":"Francis","year":"2015","journal-title":"PloS One"},{"key":"B2","doi-asserted-by":"publisher","DOI":"10.1007\/s00592-017-0971-4","article-title":"Retinal neurodegeneration in patients with type 1 diabetes mellitus: the role of glycemic variability","volume":"54","author":"Picconi","year":"2017","journal-title":"Acta Diabetol"},{"key":"B3","doi-asserted-by":"publisher","DOI":"10.1167\/iovs.15-18715","article-title":"Alterations in retinal layer thickness and reflectance at different stages of diabetic retinopathy by en face optical coherence tomography","volume":"57","author":"Wanek","year":"2016","journal-title":"Invest Ophthalmol Vis Sci"},{"key":"B4","doi-asserted-by":"publisher","first-page":"69","DOI":"10.1016\/j.sjopt.2016.12.006","article-title":"Thickness of the retinal photoreceptor outer segment layer in healthy volunteers and in patients with diabetes mellitus without retinopathy, diabetic retinopathy, or diabetic macular edema","volume":"31","author":"Ozkaya","year":"2017","journal-title":"Saudi J Ophthalmol"},{"key":"B5","doi-asserted-by":"publisher","DOI":"10.4103\/0974-620X.176098","article-title":"Quantitative spectral-domain optical coherence tomography thickness parameters in type II diabetes","volume":"9","author":"Gella","year":"2016","journal-title":"Oman J Ophthalmol"},{"key":"B6","doi-asserted-by":"publisher","DOI":"10.1371\/journal.pone.0210729","article-title":"Comparison of repeatability of swept-source and spectral-domain optical coherence tomography for measuring inner retinal thickness in retinal disease","volume":"14","author":"Hong","year":"2019","journal-title":"PloS One"},{"key":"B7","doi-asserted-by":"publisher","DOI":"10.2337\/diacare.26.2007.s94","article-title":"Nephropathy in diabetes","volume":"26","author":"Molitch","year":"2003","journal-title":"Diabetes Care"},{"key":"B8","doi-asserted-by":"publisher","DOI":"10.1111\/j.2040-1124.2011.00157.x.2012","article-title":"Corneal nerve fiber pathology in Japanese type 1 diabetic patients and its correlation with antecedent glycemic control and blood pressure","volume":"3","author":"Ishibashi","year":"2012","journal-title":"J Diabetes Invest"},{"key":"B9","doi-asserted-by":"publisher","first-page":"9","DOI":"10.1155\/2016\/3653459","article-title":"The expanded bead size of corneal C-nerve fibers visualized by corneal confocal microscopy is associated with slow conduction velocity of the peripheral nerves in patients with type 2 diabetes mellitus","volume":"2016","author":"Ishibashi","year":"2016","journal-title":"J Diabetes Res"},{"key":"B10","doi-asserted-by":"publisher","DOI":"10.1109\/TMI.2008.923966","article-title":"Intraretinal layer segmentation of macular optical coherence tomography images using optimal 3-D graph search","volume":"27","author":"Garvin","year":"2008","journal-title":"IEEE Trans Med Imaging"},{"key":"B11","doi-asserted-by":"publisher","DOI":"10.1007\/BF00400697","article-title":"A multicentre study of the prevalence of diabetic peripheral neuropathy in the United Kingdom hospital clinic population","volume":"36","author":"Young","year":"1993","journal-title":"Diabetologia"},{"key":"B12","doi-asserted-by":"publisher","DOI":"10.2337\/dc10-1303","article-title":"Toronto Diabetic Neuropathy Expert Group. 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