Corneal Tissue Addition Keratoplasty (CTAK) is an innovative treatment method for corneal ectasia, utilising the precision of femtosecond laser-assisted inlay. This article discusses a recent prospective clinical trial which demonstrated promising improvements in visual acuity and corneal topography after CTAK. These positive outcomes reinforce the recent commercial introduction of CTAK and suggest its potential as an alternate treatment method for those suffering from keratoconus.
The trial was prospective, open-label, and conducted at a single center. It evaluated the results of CTAK performed on 21 eyes belonging to 18 patients with keratoconus. A preserved corneal tissue inlay, cut to a size customized for each patient, was inserted into a channel in the host cornea created by a femtosecond laser. The main outcomes measured were postoperative uncorrected and corrected distance visual acuity (UDVA, CDVA), topographic mean keratometry (Kmean), and maximum keratometry (Kmax).
The findings, recorded six months post CTAK, were quite encouraging. The average UDVA showed a significant improvement, dropping from 1.21 logMAR to 0.61 logMAR. A total of 20 eyes (95.2%) showed an improvement of more than 2 lines of UDVA, while 10 eyes (47.6%) improved by more than 6 lines. There were no instances of UDVA decline. Average CDVA also improved, moving from 0.62 logMAR to 0.34 logMAR. Kmean decreased by -8.44 D and average Kmax decreased by -6.91 D, indicating a flattening of the cornea.
However, this study does have its limitations. The sample size was small, which can influence the reliability of the results. Also, there was no observer masking, which could potentially introduce bias.
Before CTAK, individuals with corneal ectasia were predominantly offered vision correction through specialized contact lenses, artificial instrastromal ring segments, or through more invasive procedures like penetrating or lamellar keratoplasty. Dr. Soosan Jacob’s development of corneal allogenic intrastromal ring segments (CAIRS) provided an alternative to artificial inlays. The current study adds to this by introducing CTAK, which uses femtosecond laser-cut preserved corneal tissue, as another option. The encouraging results from this study support CTAK’s recent commercial debut and may promote wider adoption of allogenic ring segments in the American healthcare system.
Financial Disclosures: Dr. Daniel Choi, involved in the study, has financial ties with Glaukos (Lecture Fees/Speakers Bureau) and Kala Pharmaceuticals (Consultant/Advisor).
Reference:
1. Jacob S et al. J Refract Surg. 2018;34:296–303
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