{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,11]],"date-time":"2026-07-11T10:05:09Z","timestamp":1783764309198,"version":"3.55.0"},"reference-count":24,"publisher":"MDPI AG","issue":"8","license":[{"start":{"date-parts":[[2026,4,18]],"date-time":"2026-04-18T00:00:00Z","timestamp":1776470400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Diagnostics"],"abstract":"<jats:p>Background\/Objectives: To evaluate the associations between corneal topographic irregularity, higher-order aberrations (HOAs), and posterior segment structural and microvascular parameters in keratoconus using optical coherence tomography (OCT) and OCT angiography (OCTA). Methods: In this cross-sectional study, 81 eyes with keratoconus and 60 healthy control eyes underwent corneal topography and wavefront analysis, spectral-domain OCT with enhanced depth imaging, and OCTA. Retinal layer thicknesses, choroidal thickness and area metrics, choroidal vascularity index (CVI), and OCTA-derived vascular parameters were analyzed. Associations were assessed using Spearman correlation analysis with false discovery rate (FDR) correction. Results: Compared with controls, keratoconus eyes showed significantly increased corneal curvature, corneal irregularity indices, and HOAs (all p &lt; 0.001). Structural OCT analysis demonstrated preserved inner retinal layers, whereas outer nuclear layer thickness was reduced (p &lt; 0.001) and overall outer retinal layer thickness was increased (p = 0.005). Choroidal thickness and both total and luminal choroidal areas were significantly greater in keratoconus eyes (all p \u2264 0.011), while CVI did not differ between groups (p &gt; 0.05). OCTA revealed reduced superficial capillary plexus vessel density at the whole image and perifoveal regions (all p &lt; 0.001), whereas deep capillary plexus and foveal avascular zone metrics were largely preserved. Correlation analyses identified only weak and inconsistent associations between corneal parameters, HOAs, and posterior segment measurements, none of which remained statistically significant after FDR correction. Conclusions: Despite pronounced anterior segment deformation and optical degradation, posterior segment structural and microvascular alterations in keratoconus are limited and weakly related to corneal disease severity. These findings support a predominantly anterior segment centered pathophysiology of keratoconus and highlight the importance of stringent multiple-comparison control in multimodal imaging studies.<\/jats:p>","DOI":"10.3390\/diagnostics16081212","type":"journal-article","created":{"date-parts":[[2026,4,20]],"date-time":"2026-04-20T07:15:08Z","timestamp":1776669308000},"page":"1212","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Corneal Higher-Order Aberrations and Posterior Segment Changes in Keratoconus: A Multimodal OCT and OCTA Study"],"prefix":"10.3390","volume":"16","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-8761-6710","authenticated-orcid":false,"given":"Ay\u015fe","family":"T\u00fcfek\u00e7i Bal\u0131k\u00e7\u0131","sequence":"first","affiliation":[{"name":"Department of Ophthalmology, Ankara Training and Research Hospital, University of Health Sciences Turkey, Ankara 06230, Turkey"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7967-0899","authenticated-orcid":false,"given":"\u00d6zlem","family":"Candan","sequence":"additional","affiliation":[{"name":"Department of Ophthalmology, Ankara Training and Research Hospital, University of Health Sciences Turkey, Ankara 06230, Turkey"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ay\u015fe","family":"Burcu","sequence":"additional","affiliation":[{"name":"Department of Ophthalmology, Ankara Training and Research Hospital, University of Health Sciences Turkey, Ankara 06230, Turkey"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Nurten","family":"\u00dcnl\u00fc","sequence":"additional","affiliation":[{"name":"Department of Ophthalmology, Ankara Training and Research Hospital, University of Health Sciences Turkey, Ankara 06230, Turkey"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,4,18]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"157","DOI":"10.1016\/j.clae.2010.04.006","article-title":"Keratoconus: A review","volume":"33","author":"Wolffsohn","year":"2010","journal-title":"Contact Lens Anterior Eye"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"101559","DOI":"10.1016\/j.clae.2021.101559","article-title":"Keratoconus: An updated review","volume":"45","author":"Carracedo","year":"2022","journal-title":"Contact Lens Anterior Eye"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"2807","DOI":"10.1007\/s10792-020-01464-8","article-title":"Posterior pole retinal thickness distribution pattern in keratoconus","volume":"40","author":"Fard","year":"2020","journal-title":"Int. Ophthalmol."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"203","DOI":"10.1159\/000350801","article-title":"Assessment of the macula in keratoconus: An optical coherence tomography and multifocal electroretinography study","volume":"229","author":"Moschos","year":"2013","journal-title":"Ophthalmologica"},{"key":"ref_5","doi-asserted-by":"crossref","unstructured":"Leclaire, M.D., Storp, J.J., Lahme, L., Esser, E.L., Eter, N., and Alnawaiseh, M. (2024). Reduced Retinal Blood Vessel Densities Measured by Optical Coherence Tomography Angiography in Keratoconus Patients Are Negatively Correlated with Keratoconus Severity. Diagnostics, 14.","DOI":"10.3390\/diagnostics14070707"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"24986","DOI":"10.1038\/s41598-024-76464-0","article-title":"Retinal neurovascular assessment and choroidal vascularity index in patients with keratoconus","volume":"14","author":"Sadeghi","year":"2024","journal-title":"Sci. Rep."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"172","DOI":"10.1007\/s10792-024-03118-5","article-title":"Higher order aberrations in keratoconus","volume":"44","author":"Erdinest","year":"2024","journal-title":"Int. Ophthalmol."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"122","DOI":"10.1016\/j.ajo.2022.10.012","article-title":"New Findings in Early-Stage Keratoconus: Lamina Cribrosa Curvature, Retinal Nerve Fiber Layer Thickness, and Vascular Perfusion","volume":"246","author":"Pierro","year":"2023","journal-title":"Am. J. Ophthalmol."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"116","DOI":"10.1016\/j.jtos.2021.12.004","article-title":"The link between Keratoconus and posterior segment parameters: An updated, comprehensive review","volume":"23","author":"Hashemi","year":"2022","journal-title":"Ocul. Surf."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"892","DOI":"10.1016\/j.survophthal.2025.11.004","article-title":"Structural alterations in the retina and choroid of keratoconus patients detected by optical coherence tomography: A systematic review and meta-analysis","volume":"71","author":"Bayat","year":"2026","journal-title":"Surv. Ophthalmol."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"411","DOI":"10.1097\/OPX.0b013e318249d727","article-title":"Aberrations and topography in normal, keratoconus-suspect, and keratoconic eyes","volume":"89","author":"Millodot","year":"2012","journal-title":"Optom. Vis. Sci."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"16486","DOI":"10.1038\/s41598-017-16568-y","article-title":"Characteristic of entire corneal topography and tomography for the detection of sub-clinical keratoconus with Zernike polynomials using Pentacam","volume":"7","author":"Xu","year":"2017","journal-title":"Sci. Rep."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"10","DOI":"10.1167\/tvst.13.1.10","article-title":"Astigmatism Influences Quantitative and Qualitative Analysis in Optical Coherence Tomography Angiography Imaging","volume":"13","year":"2024","journal-title":"Transl. Vis. Sci. Technol."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"271","DOI":"10.18502\/jovr.v16i2.9091","article-title":"Artifacts in Optical Coherence Tomography Angiography","volume":"16","author":"Anvari","year":"2021","journal-title":"J. Ophthalmic Vis. Res."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"245953","DOI":"10.1155\/2015\/245953","article-title":"Assessment of macular parameter changes in patients with keratoconus using optical coherence tomography","volume":"2015","author":"Sahebjada","year":"2015","journal-title":"J. Ophthalmol."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"676","DOI":"10.3109\/08820538.2016.1169302","article-title":"Does the Stage of Keratoconus Affect Optical Coherence Tomography Measurements?","volume":"32","author":"Uzunel","year":"2017","journal-title":"Semin. Ophthalmol."},{"key":"ref_17","doi-asserted-by":"crossref","unstructured":"Wyl\u0119ga\u0142a, A., Szkodny, D., Fiolka, R., and Wyl\u0119ga\u0142a, E. (2022). Assessment of the Retinal Vessels in Keratoconus: An OCT Angiography Study. J. Clin. Med., 11.","DOI":"10.3390\/jcm11112960"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"1199","DOI":"10.1055\/a-1743-3067","article-title":"Evaluation of Retinal Layer Thicknesses in Patients with Keratoconus Using Retinal Layer Segmentation Analysis","volume":"240","author":"Aydemir","year":"2023","journal-title":"Klin. Monatsblatter Augenheilkd."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"75","DOI":"10.4274\/tjo.galenos.2020.84748","article-title":"The Relationship Between Keratoconus Stage and the Thickness of the Retinal Layers","volume":"51","year":"2021","journal-title":"Turk. J. Ophthalmol."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"15","DOI":"10.1167\/tvst.7.3.15","article-title":"Macular Choroidal Thickening in Keratoconus Patients: Swept-Source Optical Coherence Tomography Study","volume":"7","author":"Catanese","year":"2018","journal-title":"Transl. Vis. Sci. Technol."},{"key":"ref_21","first-page":"2453931","article-title":"Increased Choroidal Thickness in Keratoconus Patients: Perspectives in the Disease Pathophysiology","volume":"2019","author":"Perestrelo","year":"2019","journal-title":"J. Ophthalmol."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"664","DOI":"10.3928\/23258160-20180831-03","article-title":"Macular and Peripapillary Choroidal Thickness in Patients with Keratoconus","volume":"49","author":"Akkaya","year":"2018","journal-title":"Ophthalmic Surg. Lasers Imaging Retin."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"103218","DOI":"10.1016\/j.pdpdt.2022.103218","article-title":"Optic disc and retinal vessel densities assessment by optical coherence tomography angiography in patients with keratoconus","volume":"41","author":"Dogan","year":"2023","journal-title":"Photodiagn. Photodyn. Ther."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"58","DOI":"10.1177\/11206721221127770","article-title":"Evaluation of the optic nerve head and macular vessel density in keratoconus patients using optical coherence tomography angiography- a cross-sectional study","volume":"33","author":"Alikma","year":"2023","journal-title":"Eur. J. Ophthalmol."}],"container-title":["Diagnostics"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2075-4418\/16\/8\/1212\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,4,20]],"date-time":"2026-04-20T07:32:36Z","timestamp":1776670356000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2075-4418\/16\/8\/1212"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,4,18]]},"references-count":24,"journal-issue":{"issue":"8","published-online":{"date-parts":[[2026,4]]}},"alternative-id":["diagnostics16081212"],"URL":"https:\/\/doi.org\/10.3390\/diagnostics16081212","relation":{},"ISSN":["2075-4418"],"issn-type":[{"value":"2075-4418","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,4,18]]}}}