Corneal Cross-Linking Associated With Temporary Rise in Eye Pressure: Study
USA: Patients who undergo corneal cross-linking (CXL) for keratoconus may experience a temporary but statistically significant increase in intraocular pressure (IOP) during the months following the procedure. Studies have shown that IOP measurements tend to rise after CXL, particularly during the first few months, before stabilizing over time.
The findings come from a study published in the Journal of Glaucoma by Sanjay G. Asrani and colleagues, who investigated changes in IOP after corneal collagen cross-linking and examined how different tonometry methods influence pressure measurements.
Keratoconus is a progressive eye disorder characterized by thinning and bulging of the cornea, leading to visual distortion. Corneal cross-linking has become a widely used treatment to slow disease progression by strengthening corneal tissue. However, because the procedure alters corneal biomechanics, concerns remain about its potential impact on intraocular pressure measurements, particularly in patients who may also be at risk for glaucoma.
To explore this issue, researchers conducted a retrospective review of patients who underwent CXL at Duke Eye Center between January 2012 and January 2024. The study included 405 treated eyes from 405 patients, along with 218 untreated fellow eyes that served as controls. Intraocular pressure measurements were collected before surgery and at approximately one month, three months, and at least 4.5 months after the procedure.
The study led to the following findings:
- Eyes treated with CXL showed a significant increase in IOP during the early postoperative period.
- Mean IOP increased by 2.2 mmHg at 1 month after CXL compared with baseline.
- IOP remained significantly elevated at 3 months, with a mean increase of 1.1 mmHg from baseline.
- By 4.5 months or later, IOP measurements had returned to baseline levels, indicating that the elevation was temporary.
- Untreated fellow eyes showed no significant changes in IOP at any postoperative time point.
- Tonopen measurements were consistently higher than iCare measurements throughout the study.
- iCare detected a significant rise in IOP at 1 month after CXL.
- Tonopen detected significant IOP elevations at both 1 month and 3 months after the procedure.
- No significant IOP elevation was observed beyond 3 months with any tonometry method.
The investigators noted that recognizing transient IOP elevations after CXL is important, particularly in patients with glaucoma or other risk factors for optic nerve damage, as temporary increases could be mistaken for disease progression.
The study was limited by its retrospective design, lack of data on corneal biomechanics and central corneal thickness, incomplete follow-up information, and evaluation of only the conventional epi-off CXL technique.
The researchers concluded that CXL does not appear to cause sustained or clinically meaningful increases in intraocular pressure. Instead, IOP rises temporarily during the early postoperative period and returns to baseline within a few months. They called for larger prospective studies with standardized tonometry protocols and corneal biomechanical assessments to better understand the relationship between CXL and IOP.
Reference:
Zhao, Wufan BS; Karl, Jamie MD; Fan, Elizabeth BA; Wisely, C. Ellis MD, MBA; Asrani, Sanjay MD. Intraocular Pressure Changes Following Corneal Cross-Linking in Patients With Keratoconus. Journal of Glaucoma 35(4):p 226-232, April 2026. | DOI: 10.1097/IJG.0000000000002689
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