Combined Procedures, Keratoconus Implant Provide Significant Improvement

The cornea plastic.
The approach demonstrated both structural and functional benefits.

Topography-guided removal of epithelium and stroma in keratoconus (TRESK) performed along with collagen cross-linking (CXL) 1 month after insertion of a corneal implant improves vision in patients with keratoconus, findings from a research team in India suggest.

Intracorneal ring segments alone are seldom enough to improve vision for patients with keratoconus, the report explains. Patients frequently require glasses, contact lenses, or additional procedures such as toric implantable collamer lens, topography, or wavefront-guided photorefractive keratectomy (PRK), according to the researchers. For contact lens-intolerant patients, only topography or wave-front-guided PRK can reduce corneal aberrations.

CXL using phototherapeutic keratectomy (PTK) to remove epithelial cells in patients with keratoconus provides better outcomes compared with manual methods, according to investigators. They propose a trans-PTK procedure, TRESK. With this technique, specific depth of stromal ablation is possible under the cone with the ability to shift the center and size of ablation to the center and size of the cone, respectively, minimizing the area of ablation. TRESK followed by CXL resulted in significant visual, topographic, and aberrometric outcomes, according to the research team.

In a prospective interventional study, 48 eyes (of 45 patients) with keratoconus underwent femto-assisted insertion with a corneal implant. After 1 month, TRESK and CXL (9 mW/cm2 for 10 minutes) were performed at the steepest tangential anterior curvature and area of the cone. Total ablation (epithelium plus stroma) was limited to 75 mm. Postoperative measurements were performed 1 month after the implant was inserted, 6 weeks after implantation followed by TRESK/CXL, and at the final visit 12 months after implantation followed by TRESK/CXL.

In all eyes studied, uncorrected distance visual acuity and corrected distance visual acuity (CDVA) improved from preoperative means of 1.05±0.05 and 0.31±0.03 logMAR to postoperative means of 0.52±0.05 (P <.001) and 0.20±0.02 logMAR (P =.009), respectively. The mean preoperative sphere, cylinder and mean refractive spherical equivalent decreased from -4.52±0.98 D, -4.81±0.25 D, -6.93±0.99 D to -0.77±0.53 D (P =.029), -3.13±0.24 D (P =.002), and -2.34±0.53 D (P =.021), respectively, with a mean keratometric flattening of 5.06D (P <.0001) at the final visit. In total, 2.08% of the eyes lost 1 Snellen line of CDVA; 68% and 27% of the eyes gained 2 Snellen lines or more of uncorrected distance visual acuity and CDVA, respectively.

The investigators note some limitations to this study, including its short follow-up time and lack of vector analysis to help interpret cylinder changes.

Disclosure: One of the study’s authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures. 


Shetty R, Israni NA, Ramuka S, et al. Intracorneal ring segments followed by simultaneous topography-guided removal of epithelium and stroma with accelerated collagen cross-linking for keratoconus (I-TRESK/CXL). Asia Pac J Ophthalmol. 2020;10(2):152-160. doi:10.1097/APO.0000000000000342