A 26-year-old man presents with several years of progressively worsening blurry vision in both eyes with frequent changes in his glasses prescription. He has a history of seasonal allergies and reports frequently rubbing his eyes. His best-corrected visual acuity is 20/40 in the right eye and 20/50 in the left. Retinoscopy reveals a scissoring reflex, and slit-lamp examination shows subtle Vogt striae. Corneal tomography shows bilateral inferior corneal steepening and thinning, more pronounced in the left eye. Six months after the initial tomography, the left eye shows further steepening and thinning.
What is the most appropriate next step in management of the left eye?
A. Continue observation with annual corneal topography
B. Fit rigid gas-permeable contact lenses alone
C. Perform corneal collagen cross-linking
D. Proceed directly to penetrating keratoplasty
E. Perform LASIK to correct the irregular astigmatism
Correct answer: C. Perform corneal collagen cross-linking
This patient has progressive keratoconus, a bilateral but often asymmetric corneal ectatic disorder characterized by progressive stromal thinning, corneal steepening, and irregular astigmatism. Typical features include a scissoring reflex on retinoscopy, inferior steepening on corneal imaging, Vogt striae on slit lamp exam, and frequent changes in refractive error.
Since serial tomography shows progression, corneal collagen cross-linking (CXL) should be the following step. This procedure uses riboflavin and ultraviolet-A light to increase corneal biomechanical stretch, thereby slowing or stopping further progression. It is the principal disease-modifying treatment for progressive keratoconus and is recommended by the AAO Preferred Practice Pattern.
A. Observation alone is inappropriate because progression has already been documented.
B. Rigid gas-permeable lenses are able to improve vision by counteracting irregular astigmatism, though they have no effect on the progression. They can be used for visual rehabilitation alongside CXL.
D. Penetrating keratoplasty is usually only carried out in cases of advanced disease, considerable corneal scarring, or when patients are unable to obtain sufficient vision using non-surgical management.
E. LASIK should not be carried out in cases of keratoconus since the removal of further stromal tissue may make the corneal ectasia worse.
Reference:
Garcia-Ferrer FJ, Akpek EK, Amescua G, Farid M, Lin A, Rhee MK, Varu DM, Musch DC, Mah FS, Dunn SP; American Academy of Ophthalmology Preferred Practice Pattern Cornea and External Disease Panel. Corneal Ectasia Preferred Practice Pattern. Ophthalmology. 2019 Jan;126(1):P170-P215. doi: 10.1016/j.ophtha.2018.10.021. Epub 2018 Oct 23. PMID: 30366794.