Mapping the Landscape: Diagnostic Tools in Corneal Health

Fitting specialty contact lenses has evolved dramatically over the past two decades. What was once a process of trial and error is now increasingly data-driven thanks to advances in anterior segment imaging. Tools such as corneal topography, tomography, anterior segment optical coherence tomography (OCT), and scleral profilometry allow clinicians to better understand the ocular surface, reduce chair time, and improve patient outcomes. Whether managing keratoconus, post-surgical ectasia, or irregular corneal surfaces, imaging provides a roadmap for efficient, confident care.

Corneal Topography

Corneal topography remains foundational in assessing irregular astigmatism and early ectatic change. It maps the curvature of the anterior corneal surface, providing essential data on steepening patterns, cone location, and overall shape.

Topography is especially useful for patient education. When a patient presents with unexplained blur or visual distortion, a topographic map can quickly demonstrate the irregularity contributing to the complaint. This visual aid supports clinical explanations and helps manage expectations for visual outcomes with specialty lenses.

However, topography has limitations. It does not assess the posterior corneal surface or overall corneal thickness. In progressive conditions such as keratoconus, relying solely on anterior data may delay diagnosis or underestimate disease severity.

Tomography and Anterior Segment OCT

To overcome the blind spots of topography, corneal tomography and anterior segment OCT provide cross-sectional imaging of both anterior and posterior corneal surfaces. These modalities allow practitioners to measure corneal thickness across the whole surface and detect subtle posterior elevation, which is often the earliest sign of ectatic progression.

Tomography is critical in evaluating suspected keratoconus, especially in younger patients or those with equivocal topography. For example, patients with mild anterior steepening may still demonstrate significant posterior elevation and inferior thinning on tomography, warranting closer monitoring or referral for cross-linking.

Additionally, tomography informs lens selection. Patients with significant thinning, asymmetry, or generalized ectasia may benefit from scleral lenses that vault the cornea entirely. Meanwhile, those with milder, more centralized irregularities may be good candidates for hybrid or custom soft lenses. In this way, imaging supports more targeted and efficient fitting strategies.

Profilometry

While tomography focuses on the cornea, scleral profilometry maps the shape and elevation of the scleral surface. This tool has transformed how practitioners approach scleral lens fitting.

Traditional scleral fitting relied on diagnostic lenses, assessment of vault and landing, and iterative adjustments. Profilometry replaces much of this trial-and-error by offering precise elevation data of the conjunctival surface. This enables practitioners to design quadrant-specific or toric haptic lenses that match scleral asymmetries from the outset.

Profilometry is especially useful in patients who present with lens discomfort or decentration despite reasonable central clearance. In many cases, these issues stem from scleral toricity or irregular elevation that standard lenses do not account for. Capturing these data preemptively can reduce remakes and improve first-fit success.

For example, consider a patient with keratoconus in one eye and a corneal graft in the contralateral eye who experiences lens instability and discomfort. Profilometry reveals significant inferior scleral elevation that wasn’t apparent during initial trial lens fitting. A custom haptic design resolves the issue immediately.

Meibography

Even the most precisely designed lens will fail if the ocular surface isn’t healthy. Meibomian gland dysfunction (MGD), lid inflammation, and unstable tear film can all undermine comfort and visual quality. As a result, integrating meibography and lid evaluation into the lens fitting process is essential.

Meibography allows visualization of gland structure and dropout, offering early insight into tear film instability. For patients reporting midday fogging or variable vision despite good lens fit, MGD is often the culprit. Addressing lid hygiene and tear quality before or alongside lens fitting can significantly improve outcomes.

In one case, a young patient with keratoconus reported frequent lens fogging that couldn’t be resolved with fit adjustments. Imaging showed excellent vault and alignment, but meibography revealed extensive gland loss. A combination of thermal therapy and at-home lid care stabilized her tear film, making her lenses comfortable and sustainable for daily wear.

Practitioners should view lid health not as an afterthought, but as an integral component of successful specialty lens wear.

Imaging as a Clinical Communication Tool

Beyond diagnostics, imaging supports stronger communication with patients. Showing a topography or tomography scan helps explain why glasses may no longer be effective. Visualizing posterior elevation or scleral asymmetry adds weight to lens recommendations that may seem complex or costly.

This visual education strengthens patient engagement. When individuals can see the cause of their symptoms and the reasoning behind the proposed solution, they are more likely to follow through with treatment and adhere to care protocols. Imaging also enables documentation of disease progression and treatment response, which helps both patient retention and long-term care planning.

In the case of progressive keratoconus or post-refractive surgery ectasia, imaging provides critical support for interventions like cross-linking or corneal transplantation. Informed patients are more empowered patients and better partners in their own care.

Improving First-Fit Success and Reducing Chair Time

One of the most tangible benefits of comprehensive imaging is increased first-fit success. By gathering full corneal and scleral data before lens design, practitioners can minimize remakes and streamline the fitting process. This reduces chair time, increases patient satisfaction, and improves overall clinic efficiency.

For high-volume practices or those working with medically complex patients, this efficiency is not just a convenience—it’s a necessity. Predictable outcomes also make specialty lenses more financially viable for both practice and patient, decreasing the likelihood of dropouts due to frustration or discomfort.

Imaging also supports scalability. As custom lens design becomes more automated and labs increasingly accept digital scans, it’s possible to move toward a virtual fitting workflow. While not yet standard, this model represents a likely future state for practices aiming to deliver personalized care without excessive chair time.

Building a Comprehensive Diagnostic Protocol

A well-structured imaging protocol ensures that no critical data are missed during the evaluation process. In our clinic, the following sequence is typical:

• Initial Screening: Corneal topography to assess anterior surface curvature.
• Structural Assessment: Tomography or anterior segment OCT to evaluate corneal thickness and posterior elevation.
• Scleral Evaluation: Profilometry for patients considered for scleral lenses.
• Ocular Surface Review: Meibography and lid margin assessment to identify MGD and tear film instability.

Each step informs the next. If topography reveals irregular astigmatism, tomography helps rule out ectasia. If a patient is a scleral lens candidate, profilometry guides haptic design. If lens fogging is reported, gland structure is evaluated.

This layered approach allows for more confident clinical decisions and reduces the guesswork that once dominated specialty lens care.

Looking Ahead

As imaging technologies evolve, the integration between diagnostic data and lens manufacturing will become even tighter. Many lens labs now accept profilometry files for custom scleral design. Eventually, practitioners may routinely perform virtual fittings using real-time modeling and direct-to-lens fabrication.

Even now, these tools enable a level of precision and customization that would have been unthinkable in the past. For patients, that means better comfort, vision, and long-term satisfaction. For clinicians, it means fewer remakes, more predictable outcomes, and a deeper understanding of the ocular surface.

The role of the eye care provider is to build a system that works in harmony with the patient’s anatomy, physiology, and lifestyle. Modern imaging technologies provide the data needed to make that system truly work.