Abstract
Purpose :
In the field of ophthalmology, precise Intraocular Pressure (IOP) measurements hinge on devices adept at engaging the corneal surface. The Tonopen and iCare tonometer’s stand out as two distinct instruments widely employed in contemporary clinics for IOP assessment. While past research attests to their equal reliability in non-pathological eyes, a notable gap persists concerning their comparative efficacy in pathological eyes—particularly those afflicted with keratoconus and treated with ultraviolet corneal crosslinking (UV-CXL). Keratoconus, a condition marked by the progressive pathological coning of corneal tissue, finds remediation through UV-CXL, a procedure aimed at arresting further corneal degeneration. With this procedure altering the composition of cornea, this retrospective study aims to evaluate the accuracy and reliability of these devices in the historical context of past procedures, emphasizing the importance of intraocular pressure monitoring in understanding patient outcomes.
Methods :
The process of this retrospective involved data analysis, specifically IOP measurements measured with iCare and Tonopen pre and post operatively on patients with diagnosed keratoconus who underwent UV-CXL. Statistical analyses assessed historical data, focusing on precision, reproducibility, and agreement between the two devices.
Results :
The retrospective analysis indicated higher variability in iCare measurements compared to Tonopen. iCare demonstrated a standard deviation of 3.94 and a coefficient of variation of 38.09%, while Tonopen exhibited lower variability (standard deviation=2.97, coefficient of variation=22.83%). Moreover, Tonopen recorded significantly higher mean intraocular pressure values (Mean=13.01) compared to iCare (Mean=10.35) with a difference of 2.66 units (P=2.97E-17).
Conclusions :
These findings suggest potential concerns regarding the consistency and accuracy of iCare measurements, as evidenced by higher variability compared to Tonopen. Clinicians should consider these discrepancies when interpreting intraocular pressure readings, particularly after UV corneal crosslinking procedure, where precision is crucial for patient safety and post-procedural success. Further investigation into the underlying factors contributing to these differences is warranted to enhance the reliability of intraocular pressure measurements in clinical practice.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.