Clinical evaluation of the decentration in different designs of scleral lenses.
Ana Privado-Aroco, María Serramito, Gonzalo Valdes-Soria, María Romaguera, Alvaro Cuellar, Mohamed Filali, Cristina Pastrana, Gonzalo Carracedo.
A new clinical study by Ana Privado-Aroco et al. (CLAE, 2025) evaluates how different scleral lens designs impact centration and how a simple, objective method can accurately measure it. The research offers important insights into why some lenses decenter, how to measure it reliably, and how to improve lens fitting outcomes.
Why Scleral Lenses Decenter
Scleral lenses often decenter during wear, typically shifting downward and toward the temple (inferotemporal). This is not just a fitting issue, it is often due to natural anatomical differences in the eye. The sclera is not symmetrical, and the nasal area tends to be flatter and more elevated, making it harder for spherical lenses to stay centered.
Why Decentration Matters
When a lens decenters, patients can experience blurred vision, distorted optics (like coma and aberrations), discomfort, and eye redness. Decentration can also lead to poor lens stability and reduced satisfaction—even when the lens appears to fit well otherwise.
“Lens decentration has significant consequences. Optically, it can displace the optical center of the lens from the visual axis, introducing prismatic effects and high-order aberrations (HOAs), such as vertical and horizontal coma.”
How the Study Was Conducted
The researchers tested 20 healthy participants using Onefit™ MED (CooperVision SEC) scleral lenses in two designs:
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SLZ (Spherical Landing Zone)
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TLZ (Toric Landing Zone)
They measured decentration after 15 minutes and again after 2 hours of wear, using a custom image-processing tool built in MATLAB. This objective method was compared to a traditional slit lamp subjective assessment using a grid.
Image of the grid used to perform the subjective measurement of lens decentration.
Image processing using Matlab_R2020b software to perform the objective measurement. The yellow dot indicates the optical center of scleral lens, the blue dot represents the pupillary center, and the red dots denote the points marked by the examiners.
Key Findings
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The MATLAB method had excellent repeatability (ICC ≥ 0.9), far outperforming manual methods (ICC < 0.5).
- Average decentration was around 0.34 mm horizontally and 0.62 mm vertically.
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Toric landing zones (TLZ) significantly reduced decentration after 2 hours of wear (p < 0.001), while spherical landing zones (SLZ) showed no improvement.
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Even with TLZ designs, some degree of decentration persisted, emphasizing the importance of accurate initial fitting.
What This Means for Fitters
Detecting and correcting lens decentration can be especially challenging for new scleral lens fitters. Subjective methods like slit lamp observation are heavily dependent on the clinician’s experience and prone to variability. An objective, data-driven approach can reduce uncertainty and increase fitting success.
How Profilometry with the ESP Helps
The Eye Surface Profiler (ESP) allows practitioners to map the scleral shape in detail, highlighting whether the sclera is spheric, toric, quad-specific, or irregular and guiding lens design decisions from the start. With accurate elevation data, the ESP helps you design the right landing zone and get closer to first-fit success, minimizing trial and error.
In light of this research, using profilometry isn’t just a time-saver; it’s a smarter way to achieve better lens centration, greater comfort, and improved visual outcomes for your patients.
Source: Ana Privado-Aroco et al., Contact Lens and Anterior Eye, https://doi.org/10.1016/j.clae.2025.102391
