Intraocular Pressure After Corneal Refractive Surgery

Ajazaj, Valbon; Kaçaniku, Gazmend; Asani, Minir; Shabani, Afrim; Dida, Ermal

doi:10.5455/medarh.2018.72.341-343

Cited by 8 publications

(7 citation statements)

References 13 publications

(3 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The sample sizes were calculated by G*power software (version 3.1.9.6). By setting α = 0.05, 1–0 = 0.95, and mean difference and standard deviation of IOP reduction tested by non-contact tonometer as 3 and 5 mmHg (effect size = 0.60) [ 7 , 8 ], a respective sample size of 32 eyes of each type of surgery was determined to be appropriate. A total of 49 patients (98 eyes) were randomly selected with a random number table from screened patients suitable for the surgery during the recruitment period, of whom 29 patients (58 eyes) underwent SMILE surgery and 20 patients (40 eyes) underwent FS-LASIK surgery.…”

Section: Methodsmentioning

confidence: 99%

Comparison of different correction formulas and measurement methods for the accurate determination of intraocular pressure after SMILE and FS-LASIK surgery

et al. 2022

View full text Add to dashboard Cite

Background To compare the accuracy of non-contact tonometry, Pentacam, and corneal visualization Scheimpflug technology (Corvis ST) for the measurement of intraocular pressure (IOP) after small incision lenticule extraction (SMILE) or femtosecond laser-assisted in situ keratomileusis (FS-LASIK) surgery. Methods A total of 49 patients (98 eyes) undergoing FS-LASIK or SMILE surgery at West China Hospital, Sichuan University from January to March 2021 were enrolled in this prospective, comparative, self-controlled study. IOP values were measured with non-contact tonometer, Pentacam, and Corvis ST before surgery and 1 month after surgery. Pentacam-derived postoperative IOP values were corrected using five correction formulas (Ehlers, Shah, Dresden, Orssengo-Pye, and Kohlhaas), while Corvis ST-derived values were corrected using a single formula. Results In the SMILE group, no significant differences were observed between the IOP values corrected with the Shah formula before and after surgery (t = 0.17, P = 0.869), whereas postoperative IOP values corrected with the other formulas were significantly different from the corresponding preoperative measurements (P < 0.05). In the FS-LASIK group, postoperative IOP values corrected with the Ehlers, Shah, or Corvis ST formulas were significantly different from the corresponding preoperative IOP measurements (P < 0.05), but no significant differences were observed between pre- and postoperative IOP values corrected with the Dresden (t = − 0.08, P = 0.941), Orssengo-Pye (t = − 0.52, P = 0.604), or Kohlhaas (t = 1.22, P = 0.231) formulas. Conclusions Pentacam’s Shah correction formula seemed to be the most appropriate method for accurately measuring postoperative IOP in patients undergoing SMILE surgery, while the Dresden, Orssengo-Pye, and Kohlhaas correction formulas of Pentacam were identified as the most reliable methods for estimating IOP in patients after FS-LASIK surgery.

show abstract

Section: Methodsmentioning

confidence: 99%

Comparison of different correction formulas and measurement methods for the accurate determination of intraocular pressure after SMILE and FS-LASIK surgery

et al. 2022

View full text Add to dashboard Cite

show abstract

“…Increasing the complexity of the modeling for the IOP does not provide any additional information. As outlined in the literature, 44 , 45 reported clinical differences between presurgical and postsurgical IOP are probably related to noncontact tonometry measurements and their correlation to corneal thickness. This seems to be why CORVIS ST provides a corrected IOP measurement that considers diverse patient biomarkers such as CCT or age.…”

Section: Discussionmentioning

confidence: 90%

“…(i) as a constant distributed surface load or (ii) as an equation of state simulating a fluid-filled cavity that allows for pressure changes within the eyeball due to external forces. 44 , 45 In both cases, IOP was set to patient's physiological value, obtained from CORVIS non-contact tonometry test; in particular, the value of the biomechanical corrected IOP (bIOP = 19.44 mm Hg) was used.…”

Section: Methodsmentioning

confidence: 99%

Establishing Standardization Guidelines For Finite-Element Optomechanical Simulations of Refractive Laser Surgeries: An Application to Photorefractive Keratectomy

Fantaci,

Calvo,

Barraquer

et al. 2024

Trans. Vis. Sci. Tech.

View full text Add to dashboard Cite

Purpose Computational models can help clinicians plan surgeries by accounting for factors such as mechanical imbalances or testing different surgical techniques beforehand. Different levels of modeling complexity are found in the literature, and it is still not clear what aspects should be included to obtain accurate results in finite-element (FE) corneal models. This work presents a methodology to narrow down minimal requirements of modeling features to report clinical data for a refractive intervention such as PRK. Methods A pipeline to create FE models of a refractive surgery is presented: It tests different geometries, boundary conditions, loading, and mesh size on the optomechanical simulation output. The mechanical model for the corneal tissue accounts for the collagen fiber distribution in human corneas. Both mechanical and optical outcome are analyzed for the different models. Finally, the methodology is applied to five patient-specific models to ensure accuracy. Results To simulate the postsurgical corneal optomechanics, our results suggest that the most precise outcome is obtained with patient-specific models with a 100 µm mesh size, sliding boundary condition at the limbus, and intraocular pressure enforced as a distributed load. Conclusions A methodology for laser surgery simulation has been developed that is able to reproduce the optical target of the laser intervention while also analyzing the mechanical outcome. Translational Relevance The lack of standardization in modeling refractive interventions leads to different simulation strategies, making difficult to compare them against other publications. This work establishes the standardization guidelines to be followed when performing optomechanical simulations of refractive interventions.

show abstract

“…It seems that the stabilization of the corneal stroma after TPRK is better in younger than in older patients. The changes in collagen crimp in both the cornea and the sclera were noted in older patients, making these tissue stiff [ 28 ]. Because age was not correlated with the difference in IOP using the two tonometers before TPRK and at W1, its significant influence one month after the TPRK study is difficult to explain.…”

Section: Discussionmentioning

confidence: 99%

The Comparison of Intraocular Pressure Measured by Transpalpebral Method Using Diaton and Rebound Tonometry by iCare in the Eyes Before and After Transepithelial Photorefractive Keratectomy (TPRK) in Saudi Arabia

Alzuhairy¹

2022

Cureus

View full text Add to dashboard Cite

Introduction: Intraocular pressure (IOP) measurement is vital to select and monitor a patient undergoing ocular surgery. The validity of tonometry by independent researchers is useful. In this paper, we compare intraocular pressure (IOP) by rebound tonometry using iCare (Tiolat Oy, Helsinki, Finland) with transpalpebral IOP (tpIOP) method by using Diaton (Bicom Inc., NY, USA) before and after transepithelial photorefractive keratectomy (TPRK) in Saudi Arabia.Methods: This cross-sectional validity study was held at a private ophthalmology hospital in central Saudi Arabia from January 2021 to February 2022. The tonometry was performed before, at week 1 (W1), and month 1 (M1) after TPRK. The tpIOP and IOP by iCare were compared using matched-pair analysis. The agreement in IOP by two methods was reviewed using the Bland-Altman plot. Central corneal thickness (CCT), spherical equivalent (SE) before surgery, and gender were correlated to the difference in IOP by two tonometers. The main outcome was the difference in IOP measured by Diaton and iCare.Results: We studied 202 eyes of 101 patients. The median difference in IOP by Diaton and iCare was -1.0 mmHg before, at W1, and M1 follow-ups. Before surgery, tpIOP by Diaton was 15.0±2.8 mmHg and by iCare was 16.0±3.7 mmHg (P<0.001). At W1, tpIOP was 15.9±2.5 mmHg and 16.9±3.4 mmHg by iCare (P<0.001). At M1, tpIOP was 15.7±4.1 mmHg and 16.5±5.4 mmHg by iCare (P<0.001). IOP by two methods was within ±2 mmHg in 73.3%, 69.8%, and 75.2% of the eyes before, at W1, and M1 of TPRK. Pre-CCT (P<0.001) was the significant predictor of the difference in IOP by two methods at W1 and M1 (P=0.001). iCare gave the overestimation of IOP compared to Diaton in 18.3%, 22.8%, and 17.8% of the eyes before, W1, and M1 follow-ups.Conclusions: IOP by iCare and Diaton was similar. Central corneal thickness was the predictor of IOP differences by tonometers.

show abstract

Intraocular Pressure After Corneal Refractive Surgery

Cited by 8 publications

References 13 publications

Comparison of different correction formulas and measurement methods for the accurate determination of intraocular pressure after SMILE and FS-LASIK surgery

Comparison of different correction formulas and measurement methods for the accurate determination of intraocular pressure after SMILE and FS-LASIK surgery

Establishing Standardization Guidelines For Finite-Element Optomechanical Simulations of Refractive Laser Surgeries: An Application to Photorefractive Keratectomy

The Comparison of Intraocular Pressure Measured by Transpalpebral Method Using Diaton and Rebound Tonometry by iCare in the Eyes Before and After Transepithelial Photorefractive Keratectomy (TPRK) in Saudi Arabia

Contact Info

Product

Resources

About