Keratoconus is a progressive corneal disease marked by central steepening and ectasia, but its progression and definition remain unclear. This case report highlights successful scleral lens fitting in an older patient despite rapid keratoconus progression.

Case Description

A 35-year-old Hispanic female patient with a history of previous scleral lens wear was referred for a new fitting due to frequent discomfort with her previous lenses. She reported having received a diagnosis of keratoconus 5 years earlier. She also reported sinus-related seasonal allergies but did not recall rubbing her eyes in the past. The only medication reported was loratadine.

Slit lamp evaluation revealed a 4-mm central, stromal corneal scar OD and central thinning of the cornea OS. A prominent Munson’s sign was noted in each cornea. All other slit lamp findings were unremarkable. Due to the corneal scarring, K values were not obtainable OD but were 47.00D/56.70D@ 002 OS. Posterior segment findings were normal. Owing to the thinner profile, InSight Scleral lenses (Metro Optics) were chosen for this patient.

A successful fit was accomplished with the prolate design and a sagittal depth of 4,500 µm in both eyes with a standard corneal chamber and spherical landing zone. Best-corrected acuities in the scleral lenses were 20/100 in the right eye (limited by the corneal scar) and 20/30 in a -10.00 DS and -7.50 DS, respectively. The patient reported improved comfort compared with her previous lenses.

Through multiple routine follow-ups over the next 6 months, significant steepening of the cornea of the left eye was noted on anterior segment optical coherence tomography (see Figure 1). The patient reported a history of uncomplicated scleral lens wear, good vision, and no significant change in medical history. Over the 6 months, keratometry values of the left eye progressed from 47.00/56.75D to 52.25/63.00D.

Despite the surprisingly rapid progression of central steeping, the scleral fit remained satisfactory, and no changes were recommended. Corneal crosslinking was discussed, but the patient elected not to proceed due to her uninsured status and inability to afford the out-of-pocket cost.

Discussion

This case highlights an uncommonly rapid progression of keratoconus in an older patient, and despite the significant change in keratometry, the sagittal depth of the cornea remained relatively stable. While there is an association between steeper K values and increased sagittal depth, these characteristics are independent.

Conclusion

This case demonstrates that as the cornea steepens over time (even in rapidly progressing cases), the sagittal depth of the cornea may not change. While progression in keratoconus typically occurs in younger age groups, it is difficult to truly assess the potential for progression; thus, patients must be followed regularly if timely intervention such as crosslinking can be recommended. 

Andrew Kemp, OD, is a clinical assistant professor at University of Houston College of Optometry. Dr. Kemp has received speaker honorarium from Metro Optics.

To hear Dr. Kemp discuss this case, click here.