Agreement of Corvis ST Biomechanical IOP Measurements With Pachymetry-Based Correction Formulas in Patients With Keratoconus: A Comparative Analysis According to Disease Severity.

Λεπτομέρειες βιβλιογραφικής εγγραφής
Τίτλος:	Agreement of Corvis ST Biomechanical IOP Measurements With Pachymetry-Based Correction Formulas in Patients With Keratoconus: A Comparative Analysis According to Disease Severity.
Συγγραφείς:	Aydın FO; Department of Ophthalmology (F.O.A., Y.B.A., İ.Ç.A., S.E., B.K.Y.), University of Health Sciences, Basaksehir Cam and Sakura City Hospital, Istanbul, Turkey; and Department of Ophthalmology (A.C.), Akdeniz University, Antalya, Turkey., Ceylan A, Akbaş YB, Çelen Arabacı İ, Ermiş S, Kepez Yıldız B
Πηγή:	Eye & contact lens [Eye Contact Lens] 2026 Sep 01; Vol. 52 (9), pp. 362-367. Date of Electronic Publication: 2026 May 18.
Τύπος έκδοσης:	Journal Article; Comparative Study
Γλώσσα:	English
Στοιχεία περιοδικού:	Publisher: Lippincott Williams & Wilkins Country of Publication: United States NLM ID: 101160941 Publication Model: Print-Electronic Cited Medium: Internet ISSN: 1542-233X (Electronic) Linking ISSN: 15422321 NLM ISO Abbreviation: Eye Contact Lens Subsets: MEDLINE
Imprint Name(s):	Original Publication: Hagerstown, Md. : Lippincott Williams & Wilkins, c2003-
Ιατρικοί όροι (MeSH):	Keratoconus/physiopathology , Keratoconus/diagnosis , Intraocular Pressure/physiology , Tonometry, Ocular/methods , Tonometry, Ocular/instrumentation , Corneal Pachymetry/methods , Cornea*/physiopathology, Humans ; Male ; Adult ; Prospective Studies ; Female ; Cross-Sectional Studies ; Severity of Illness Index ; Corneal Topography ; Young Adult ; Biomechanical Phenomena ; Adolescent
Περίληψη:	Objectives: To evaluate the agreement of intraocular pressure (IOP) measurements obtained by Corvis ST using biomechanically corrected IOP (bIOP), noncontact tonometry (NCT), and pachymetry-based correction formulas (Ehlers, Shah, Dresden, Spoerl) across different keratoconus severity levels and in comparison with healthy control eyes. Methods: This prospective, cross-sectional study included 77 patients with keratoconus (77 eyes), categorized by severity using Pentacam-based Topographic Keratoconus Classification and 54 healthy control patients. Patients underwent corneal tomography, and IOP was measured with Corvis ST. Uncorrected NCT-IOP (IOPnct), biomechanically corrected IOP (bIOP), and pachymetry-based corrected IOP (Ehlers, Shah, Dresden, Spoerl) were compared. Agreement among methods was assessed using Bland-Altman analysis. Results: The mean patient age was 26.4±7.3 years (59.7% male). NCT consistently underestimated IOP compared with bIOP, while Ehlers (+2.6 mm Hg), Shah (+1.4 mm Hg), and Dresden (+0.7 mm Hg) formulas significantly overestimated ( P <0.001). The Spoerl formula (-0.9 mm Hg) showed no significant difference compared with bIOP ( P =0.209). Bland-Altman analysis confirmed that the Spoerl formula had the smallest bias and narrowest limits of agreement across all keratoconus stages. Differences between methods became more pronounced with increasing severity, particularly evident for Ehlers and Shah formulas. In healthy control eyes, the different IOP estimation methods showed relatively small bias relative to bIOP. Conclusions: Noncontact tonometry significantly underestimates, and common pachymetry-based corrections (Ehlers, Shah, Dresden) tend to overestimate IOP in keratoconic eyes. The Spoerl formula provides IOP values most closely aligned with the Corvis ST bIOP across all keratoconus stages and was the most consistent pachymetric correction method relative to this biomechanically corrected comparator. Agreement between methods was closer in healthy corneas than in keratoconic eyes, supporting the influence of altered corneal biomechanics on tonometric measurements. (Copyright © 2026 Contact Lens Association of Ophthalmologists.)
Competing Interests:	The authors have no funding or conflicts of interest to disclose.
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Contributed Indexing:	Keywords: Corvis ST; IOP correction formulas; Keratoconus; bIOP
Entry Date(s):	Date Created: 20260518 Date Completed: 20260821 Latest Revision: 20260928
Update Code:	20260928
DOI:	10.1097/ICL.0000000000001284
PMID:	42144724
Βάση Δεδομένων:	MEDLINE

Περιγραφή
ISSN:	1542-233X
DOI:	10.1097/ICL.0000000000001284