The new mantra of keratoconic care: Diagnose early, Stop progression, Rehabilitate vision. The following case will demonstrate the ability of corneal collagen crosslinking to stop progression of keratoconus. This case shows the clinical benefits of crosslinking in a twenty-year-old (in the progressive age range) and at the same time how fast the disease can progress if left untreated.

Let’s set the scene:

A 20-year-old male presented with complaints of decreasing vision and difficulty driving at night, his right eye was worse than the left eye. He had seen multiple doctors, had multiple pairs of glasses and daily disposable soft contact lenses, all of which offered little-to-no improvement. He was determined to fix the problem once and for all and arrived for a LASIK consultation.

The new mantra of keratoconic care: Diagnose early, Stop progression, Rehabilitate vision. The following case will demonstrate the ability of corneal collagen crosslinking to stop progression of keratoconus. This case shows the clinical benefits of crosslinking in a twenty-year-old (in the progressive age range) and at the same time how fast the disease can progress if left untreated.

Let’s set the scene:

A 20-year-old male presented with complaints of decreasing vision and difficulty driving at night, his right eye was worse than the left eye. He had seen multiple doctors, had multiple pairs of glasses and daily disposable soft contact lenses, all of which offered little-to-no improvement. He was determined to fix the problem once and for all and arrived for a LASIK consultation.

The pertinent stats:

VAsc
OD: 20/100
OS: 20/50

VAcc (7-month-old spectacles)
OD: 20/50
OS: 20/30

Refraction
OD: +1.50-4.25×050 20/30-
OS: +0.50-2.25×145 20/25-

Slit lamp examination is unremarkable except the cornea in each eye shows inferior central thinning and grade 1+ striae.

Corneal tomography was performed:

Right eye:

Left eye:

It is clear to see the keratoconic pattern on the maps above, the right looks like a more severe mirror image of the left, the top left axial curvature map showed irregular inferior temporally displaced corneal steeping, the top right front surface elevation map showed irregular elevation through a best fit sphere, similar but more exaggerated elevation changes are observed on the bottom right posterior corneal elevation map, and the bottom left cornea thickness map shows thinning corneal thinning.

Metrics of interest:

Point of Maximum Keratometry (Kmax)
OD: 53.3D
OS: 49.1D

Thinnest Point:
OD: 421µ
OS: 419µ

The patient was diagnosed with Keratoconus, educated about the progressive nature of keratoconus, and lack of candidacy for LASIK. Crosslinking was discussed as a treatment for stabilization/ progression prevention of the disease, and specialty contact lenses are discussed for visual rehabilitation. The plan was to perform crosslinking on the right eye first, then the left eye, followed by fitting specialty lenses for improved vision.

2 weeks later uncomplicated crosslinking was performed on the right eye under the FDA approved protocol: the central 9mm of epithelium was removed, riboflavin drops (Avedro Photexra Viscous = riboflavin 5’-phosphate in 20% dextran ophthalmic solution) drops were applied every 2 minutes for 30 minutes, then corneal riboflavin uptake was checked for full  saturation, corneal thickness was checked and hypotonic riboflavin (Avedro Photexra = riboflavin 5’-phosphate ophthalmic solution)  was applied until corneal pachymetry measured greater than 400 microns(If >400 um, proceed with UV, if <400 um, administer hypotonic riboflavin drops every 10 seconds for 2 minutes until swells to ≥400 um). Then the cornea is irradiated with UV (Avedro KXL) at a wavelength of 365 nm UVA, and power of 3mW/cm2 for 30 minutes. After an ice cold balanced salt solution rinse, a bandage lens was placed on the eye along with a drop of antibiotic and steroid.

Day 1 and day 5 follow-ups were uneventful, with the epithelium fully healed, the bandage lens was removed at day 5 and the antibiotics were discontinued, and the 4-week steroid taper begun. The patient was scheduled for a 1 month follow-up, but…1 year later the patient arrives, this time his complaint is that vision in the untreated left eye has rapidly decreased.

The pertinent stats:

VAsc
OD: 20/100
OS: 20/200

VAcc (1-year-old spectacles)
OD: 20/30-
OS: 20/60

Refraction
OD: +1.00-3.50×053 20/25+
OS: +0.50-3.75×132 20/30-

Slit lamp examination is unremarkable except the cornea in each eye shows inferior central thinning and grade 1+ striae, and the right cornea has trace diffuse haze.

Corneal tomography was performed:

Right eye 1-year post-crosslinking

Left eye 1 year later, no treatment

Right eye difference map:

Left eye difference map:

Right eye 1 year ago:
Kmax: 53.3D
Right eye 1-year post CXL:
Kmax: 51.4D
Right eye difference in 1 year:
Kmax change: -2.0D

Left eye 1 year ago:
Kmax: 49.1D
Left eye untreated 1 year later:
Kmax: 54.1D
Left eye difference in 1 year:
Kmax: +5.0D

Reviewing the right eye maps, it clear to see the efficacy of corneal collagen crosslinking. After 1 year the treated right eye maximum corneal curvature has not just stabilized, it has improved and flattened by 2.0 diopters. On the untreated left eye maximum, corneal curvature progressed and steepened by 5.0 diopters.

That’s huge! Treated right eye = 2 diopters flatter! Untreated left eye = 5 diopters steeper!

Now if only the patient could go back in time and follow up at the suggested time frame. If we had performed crosslinking at that time, 1 year ago, and the patient had a similar 2.0 diopter flattening effect, the left eye maximum corneal curvature one year after treatment could have been 47.1 diopters.

This case demonstrates not only the efficacy of corneal collagen crosslinking, but also the progressive nature of keratoconus, and the importance of proper follow-up. A lot can happen in just 12 months. Individuals in the progressive age range need to be followed frequently and even crosslinked corneas need to be followed closely for changes because even though it is very rare, keratoconus can still progress despite crosslinking.