Posters

Ring-pattern local corneal cross-linking: in vivo and clinical study of corneal morphological, biomechanical and optical changes

Poster Details

First Author: S.Anisimov RUSSIA

Co Author(s):    S. Anisimova   N. Anisimova                 

Abstract Details

Purpose:

To assess corneal morphological, biomechanical and optical changes after local crosslinking (CXL) in clinical setting and ex vivo.

Setting:

Eye Center "East Sight Recover", Moskow

Methods:

20 patients (20 eyes) from 18 to 45 years old (12 female, 8 male) were included in the study with keratoconus Stage I-III. Keratometry (Sim K) indices, visual acuity (VA) (decimal) and corneal hysteresis were analyzed before and 6 months after epi-off CXL treatment. The ring-pattern was used to irradiate the cornea both in clinical and in vivo study (central cornea did not undergone irradiation). In vivo study was performed on 9 rabbits (9 eyes) of the chinchilla breed with the same protocol. Ultrastructural analysis was done with transmission scanning electron microscopy of the corneas after in vivo experiment.

Results:

After local corneal CXL, we noted the phenomenon of inconsistency in keratometric changes and VA.  Sim K increased or remained unchanged (from 46.11±3.01 to 47.91±3.23), and VA increased into 2 times (from 0.31±0.13 to 0.70±0.26). At the same time, postoperative corneal hysteresis parameters increased in 17.0±2.4%. Ultrastructural images after local corneal CXL in vivo showed that the fibrous structure of collagen form annular structures similar in size to wavelength of the light. Such ring-shaped structures can have the properties of meta-optics, which substantially change the refractive index of the corneal tissue explaining VA improvement.

Conclusions:

Ring-pattern local CXL changes the optical density of the corneal tissue in the area of treatment (paracentral) and the central area remains intact. This change distorts keratometry data, especially when using mirror topographic systems. Further investigation of the corneal meta-optical effects of CXL is required.

Financial Disclosure:

None