New Modified Applanation Tonometer To Use After Laser Refractive Surgery: Correlations With Goldmann Tonometer And Ocular Response Analyzer After One Year.
Published 2024 - 42nd Congress of the ESCRS
Reference: PP21.11 | Type: Free paper | DOI: 10.82333/ytkg-9t18
Authors: María Iglesias* 1 , Bachar Kudsieh 2 , Francisco Yebra 3 , Clara Bonel 4 , Anton Barraquer 4
1Ophthalmology,Hospital San Rafael,Barcelona,Spain;Ophthalmology,Barraquer Institute,Barcelona,Spain, 2Ophthalmology,Hospital Puerta de Hierro,Madrid,Spain, 3Ophthalmology,University of Vigo,Barcelona,Spain, 4Ophthalmology,Barraquer Ophthalmology Center,Barcelona,Spain
Purpose
To describe long term intraocular pressure (IOP) measurements post myopic laser assisted in situ keratomileusis (LASIK), or photorefractive keratectomy (PRK) procedures, using a new modified applanation tonometer with a convexly shaped apex (CT) in correlation with Goldmann applanation tonometer (GAT) and Ocular Response Analyzer (ORA).
Setting
The study was carried out on myopic subjects that were going in for laser refractive surgery: LASIK or PRK at the Barraquer Ophthalmology Center in Barcelona, Spain.
Methods
Prospective double-blind comparative study between the CT, the GAT and the ORA. By using finite element analysis simulation, 2 different radii were designed for the new CT: CT1 and CT2. In a first phase, GAT was compared with CT1 and CT2 before and 3 months (m) after surgery in n=102 patients (LASIK (n=73) and PRK (n=29)) in correlation with ORA corneal parameters. In a second phase, GAT, CT1 and ORA were evaluated before, at 3 months and after 12 months in n=30 patients. In all series, the intraclass correlation coefficient (ICC) and the Bland-Altman graph (B-A) were calculated for the concordance between GAT and CT; and IOPg (IOP correlated with Goldmann) and IOPcc (IOP with corneal compensation) from ORA were calculated after one year.
Results
After 3m, CT1 showed greater agreement with GATpre compared to CT2, being more accurate for LASIK, ICC = 0.718 (95% CI: 0.594-0.812) than PRK, ICC = 0.578 ( 95% CI: 0.182-0.795). B-A showed good concordance with lower values between GATpre and CT1post for LASIK, -0.19, than PRK,1.62 (p <0.001). Differences between CT1post and GATpre presented a bias related to the corneal resistance factor (p <0.001). ICC was > 0.8 (95% CI) in all cases.
After 12m post LASIK, CT1 showed the best correlation with GATpre ICC = 0.886 (95% CI: 0.703 - 0.956) compared to IOPcc ICC = 0.568 (95% CI: -0.185 - 0.843). 12m after PRK, CT1 showed a weak correlation with GATpre ICC = -0.266 (95% CI: -3.896 - 0.663) and with IOPcc ICC = 0.256 (95% CI: -0.332 - 0.719).
Conclusions
CT1 was strongly correlated with GATpre after 3 and 12 months post LASIK comparing to PRK soubgroup. Therefore, this new device could provide a more accurate alternative method to measure IOP in LASIK patients, in contrast with GAT or ORA.