Corneal cross-linking (CXL) is universally accepted in the management of corneal ectasia; however, there are fewer publications on the sequencing or timing of when CXL or scleral lenses should be performed.^1,2 CXL stabilizes the cornea, however CXL is not a refractive procedure and does not correct corneal irregularity that causes decreased best spectacle-corrected visual acuity (BSCVA). Specialty contact lenses are beneficial to achieve improved vision after CXL. Specialty contact lenses may be offered first if vision is unacceptable to perform activities of daily living. Alternatively, CXL can be performed first if topographical signs and objective evidence indicate significant progression.³

A prospective study evaluated whether scleral fittings before CXL result in a substantial change in lens parameters preoperatively compared with postoperatively.⁴ The findings of this study could consolidate the scleral lens fitting process and reduce the need for additional postoperative visits, enabling patients to maintain productive lives with optimal vision.

This study evaluated four individuals (six eyes) who had keratoconus and three individuals (five eyes) who had post–laser-assisted in situ keratomileusis (LASIK) corneal ectasia. All eyes were fitted with scleral lenses by a single practitioner, then underwent epithelium-off CXL surgery using the Dresden protocol performed by the same surgeon.

A diagnostic scleral lens was applied on the eyes and evaluated by slit lamp evaluation. The goal of fitting the scleral lens was 200mm to 300mm of central clearance and 50mm to 100mm of limbal clearance. Lens power was determined by sphero-cylindrical overrefraction over the diagnostic lens. Base curve, sagittal height, overrefraction, and best-corrected visual acuity with the scleral lens in Snellen values were recorded. 

Topographic and refractive parameters, along with uncorrected visual acuity, BSCVA, and best scleral visual acuity were recorded preoperatively and compared to values at one and three months postoperatively.

Overall, there were no significant differences between pre- and postoperative corneal measurements or refractive correction. These findings indicate that scleral fittings could be initiated before CXL to streamline the scleral lens prescription process post-procedure. This study supports the idea that a scleral lens can be safely fit before CXL and resumed one month postoperatively.

REFERENCES

1. Koppen C, Gobin L, Mathysen D, Wouters K, Tassignon MJ. Influence of contact lens wear on the results of ultraviolet A/riboflavin cross-linking for progressive keratoconus. Br J Ophthalmol. 2011 Oct;95:1402-1405.

2. Mandathara PS, Kalaiselvan P, Rathi VM, Murthy SI, Taneja M, Sangwan VS. Contact lens fitting after corneal collagen cross-linking. Oman J Ophthalmol. 2019 Oct 11;12:177-180.

3. Saenz B, Mueller B. Scleral Lenses or CXL: Which Should Come First? Modern Optometry. 2020 Jan/Feb. Available at modernod.com/articles/2020- jan-feb/scleral-lenses-or-cxl-which-should-come-first?c4src1/4article:infinite-scroll. Accessed 2025 Jan 2. 

4. Aisien F, Di Meglio L, Bower K, Crum A. Topographical and Refractive Outcomes After Corneal Cross-linking in Novice Scleral Lens Users. Eye Contact Lens. 2025 Jan 22. [Online ahead of print]

Melissa Barnett, OD, FAAO, FSLS, is the director of optometry at the University of California, Davis. She has received remuneration from ABB, Abbvie, Alcon, Azura, Bausch + Lomb, BCLA, Bruder, Bruno Vision Care, Cloudbreak Pharma, CooperVision, Dompé, Epion, JJVC Vistakon, Lentechs, Ocusoft, Orasis, ScienceBased Health, STAPLE Program, Tarsus, Théa Pharma, and Visus Therapeutics.

 This editorial content was supported via unrestricted sponsorship.