Forward-scattered and backward-scattered light in moderate keratoconus



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Villanueva Gómez-Chacón, Celia and Viviano, Francesco and García Montero, María and Lorente Velázquez, Amalia and Martínez Alberquilla, Irene and Garzón Jiménez, Nuria (2023) Forward-scattered and backward-scattered light in moderate keratoconus. Ophthalmic and Physiological Optics . 8 p.. ISSN 0275-5408

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Introduction: To evaluate the backscattered light, objective scatter index (OSI) and retinal straylight in patients with moderate keratoconus and healthy control subjects.
Methods: A prospective observational study was developed with 33 patients in the moderate-keratoconus group (KC) and 34 in the non-keratoconus group (NKC). Corneal densitometry was obtained using Scheimpflug corneal tomography and measurements were expressed in grayscale units (GSU) over four zones within a 12.00 mm diameter around the corneal apex. A straylight meter was used to determine the amount of intraocular straylight under scotopic conditions, and the straylight parameter (LOG(s)) and test duration were recorded. The Optical Quality Analysis System based on the double-pass technique determined the OSI value.
Results: Significant differences were observed between the KC and NKC groups for corneal densitometry (except in the 6–10 mm zone), OSI and retinal straylight. A moderate and significant correlation was found between OSI and retinal straylight LOG(s) (r = 0.52, p = 0.002). Weaker and non-significant correlations were found between corneal densitometry and the other parameters analysed (i.e., OSI, retinal straylight LOG(s) and retinal straylight times).
Conclusions: Backscattered light, retinal straylight and the OSI show clear differences between healthy eyes and those with moderate KC. The changes present in the stages of KC evaluated in the current study (stages II and III according to the Amsler–Krumeich classification) might alter the scattering of the light entering the eye.

Item Type:Article
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Version of Record online: 15 March 2023; Manuscript accepted: 01 March 2023; Manuscript revised: 17 February 2023; Manuscript received: 20 October 2022

Uncontrolled Keywords:Backward scattering; Corneal densitometry; Forward scattering; Keratoconus; Retinal straylight
Subjects:Medical sciences > Medicine > Ophtalmology
Medical sciences > Optics > Eyes anatomy
Medical sciences > Optics > Physiological optics
ID Code:77029
Deposited On:15 Mar 2023 20:08
Last Modified:21 Mar 2023 09:41

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