In last month’s column, I talked about when corneal collagen crosslinking (CXL) should precede contact lens fitting in keratoconus (KCN) patients. (See bit.ly/OM0424CXLContactLensColumn.) This month’s column continues the CXL conversation with the action steps optometrists should follow after CXL to increase the likelihood of successful contact lens (CL) wear.

Time the fit
Although the corneal tissue will continue to remodel and flatten after the procedure, patients may begin or resume CL wear relatively shortly after reepithelialization.

I have found this is typically 2 months for experienced wearers and 3 months for new wearers.

I find it wise to wait a bit longer to fit new wearers to avoid potential corneal trauma due to their inexperience in CL handling.

Manage expectations
Topographical changes will occur throughout the 24-month post-operative period. Initial steepening is followed by continued surface healing, stromal compaction, and continuous flattening; typically 1.00 D to 2.00 D.¹

These topographical changes may also alter the axis and amount of astigmatism within the first 12 months.² Thus, ODs should inform the patient that periodic adjustments to their contact lens fit or prescription may be necessary.

For example, it is expected that the soft CL-wearing patient will undergo one or more prescription changes within the first 3 months of wear because this CL type conforms to the cornea’s shape.

In cases of RGP, hybrid, and scleral CL wear, however, the underlying tear layer will compensate for mild corneal flattening.

This characteristic makes prescription and fit adjust-
ments rarely necessary, as the vault and power changes are clinically insignificant.

Monitor corneal health
On a histologic level, there is a decrease in basal cells and neural plexus density following CXL.³ This may create some level of corneal hypoesthesia. Therefore, it is important the optometrist monitor corneal health more frequently upon fitting or refitting CLs, as patients may have reduced sensitivity to minor corneal insults.

My follow-up schedule for both habitual and new wearers is 3 months, 6 months, and 12 months.

When applicable, I provide these patients with an updated spectacle prescription for 3 months.

At 6 months, I authorize a prescription for spare or planned-replacement CLs.

Meeting a need
The benefits of the early diagnosis of keratoconus and the referral for CXL are setting
new standards for the optometric management of patients who have corneal ectasia.

Therefore, it’s important for the co-managing optometrist to know the action steps outlined above, so they can provide optimal CL fitting post CXL for these patients. OM

References
1. Del Buey MA, Lanchares E, Cristóbal JÁ, et al. Immediate effect of ultraviolet-a collagen cross-linking therapy on the biomechanics and histology of the human cornea. J Refract Surg. 2015;31(1):70-71. doi: 10.3928/1081597X-20141218-08.

2. Chang CY, Hersh PS. Corneal Collagen Cross-Linking: A Review of 1-Year Outcomes.
Eye Contact Lens. 2014 Nov;40(6):345-52. doi: 10.1097/ICL.0000000000000094.

3. Sehra SV, Titiyal JS, Sharma N, Tandon R, Sinha R. Change in corneal microstructure with rigid gas permeable contact lens use following collagen cross-linking: an in vivo confocal microscopy study. Br J Ophthalmol. 2014;98(4):442-7. doi: 10.1136/bjophthalmol-2013-303934.

Susan A. Resnick, OD, FAAO is president and managing partner at Drs. Farkas, Kassalow, Resnick, and Associates, a contact lens and anterior segment specialty practice in New York. She is a diplomate in the Cornea, Contact Lens, and Refractive Technology section of the AAO, a diplomate of the ABO, and a fellow of the Scleral Lens Education Society.