Corneal microectasia after laser refractive surgery: a new observation

Session Details

Session Title: Primary and Secondary Ectasia

Session Date/Time: Sunday 23/09/2018 | 08:00-10:00

Paper Time: 08:00

Venue: Room A4

First Author: : F.Carones ITALY

Co Author(s): :    L. Vigo                    

Abstract Details

Purpose:

Ectasia after corneal laser refractive surgery remains a threatening complication. The purpose of this study was to identify metrics to define the evidence of non-clinically significant features of corneal ectasia in eyes that underwent myopic laser vision correction. At this purpose we used a spectral domain high-resolution anterior segment OCT to measure anterior and posterior corneal curvature, and epithelial layer thickness.

Setting:

Carones Ophthalmology Center (private eye care clinic), Milan, Italy

Methods:

Over a one-year period, we evaluated 720 patients for a total of 1426 eyes who received myopic laser vision correction (surface ablation and LASIK) at least one year before. Patients with clinically evident ectasia were excluded from this study, as well as patients showing any suspicious anterior corneal curvature finding leading to the suspect of ectasia (especially when associated with posterior curvature bulging). We used the MS-39 (CSO, Italy) to assess the anterior and posterior corneal curvature, and the epithelial layer thickness. More in details, we focused the relation between epithelial thickness and posterior corneal curvature bulging.

Results:

1420 eyes were included in the study. 1325 eyes (94%) showed no posterior curvature bulging, and the epithelial layer was relatively thicker in the center of the ablation than the surrounding areas, or it had consistent thickness . The remaining 85 eyes (6%) showed some degree of posterior bulging. Of these, 30 eyes (35.3%, 2.1% of the total group) showed thinner epithelium matching the bulging area, then thicker epithelium surrounding this area in a doughnut-shaped fashion. This finding is exactly like the thinning of the epithelium detectable on the apex of keratoconic eyes. Anterior corneal curvature was normal.

Conclusions:

For eyes with normal anterior corneal topography after myopic laser refractive surgery, we hypothesize the thinning of the corneal epithelium over a posterior curvature bulging area to be an indicator for sub-clinical corneal ectasia, in accordance to what happens in eyes with keratoconus. We coined the name “microectasia” to define this observation, which involves circa 2% of routine eyes examined after myopic laser vision correction. Follow-up on these patients seems to be mandatory to ensure non-progression and evaluate corneal cross-link as an option. Laser enhancements may be not advisable in these eyes.

Financial Disclosure:

... receives consulting fees, retainer, or contract payments from a company producing, developing or supplying the product or procedure presented