This is a prospective, Phase I open-label safety study to evaluate the safety, feasibility and initial efficacy of a bioengineered corneal stromal substitute after implantation into the stroma of adults with advanced keratoconus. The bioengineered substitute and implantation technique may provide a less invasive treatment option for advanced keratoconus than current surgical approaches, that additionally does not rely on the limited availability of human donor corneal tissue.

This is a Phase I, open-label, non-randomized, non-controlled ongoing clinical case series in two participating centers in Indian and Iranian hospitals, to evaluate the safety and feasibility of minimally-invasive surgery of advanced keratoconus using a bioengineered corneal stromal substitute on a compassionate basis to alleviate blindness and low vision, due to the severely limited availability of human corneal donor tissue at these centers relative to the medical need. Patients fulfilling inclusion criteria are recruited consecutively and implanted intra-stromally with the bioengineered substitute, as a less invasive surgery than full-thickness or anterior lamellar corneal transplantation. In the first phase of the study, a total of 20 patients were recruited and safety and efficacy outcomes were evaluated in those having a minimum of 12 months of postoperative follow-up. In the second phase of the study (currently ongoing), up to 40 patients are being recruited, with one-year postoperative outcomes of all included patients to be evaluated as the final study endpoint. Primary safety and efficacy outcomes will be evaluated.

Inclusion Criteria:

• Advanced keratoconus (according to Amsler-Krumeich classification)
• No corneal scar
• Male or female aged ≥ 18 years, no upper age limit
• Subjects indicated for a first corneal stromal transplantation (treatment naïve)
• Corneal thickness (including epithelium) at least 300µm centrally, as measured by OCT.
• Patients who gave their written signed and dated informed consent for participation

Exclusion Criteria:

• Prior corneal surgery (e.g., refractive surgery, cataract, collagen cross-linking, endothelial keratoplasty, etc.)
• Dry eye / tear film pathology
• Active ocular infection
• Glaucoma / ocular hypertension
• Active corneal ulceration
• Acute or chronic disease or illness that would increase the operation risk or confound the outcomes of the study (immune- compromised, connective tissue disease, clinically significant atopic disease, etc.)
• Any other medical condition that in the judgment of the clinical investigator or corneal surgeon is not compatible with the study procedures
• General history judged by the investigator to be incompatible with the study (e.g., life-threatening patient condition, other condition where postoperative follow-up may be difficult).
• known diabetes or other neuro-degenerative disorder (as corneal nerves can be affected leading to impaired wound healing)
• Inability of patient to understand the study procedures and thus inability to give informed consent.
• Participation in another clinical study within the last 3 months
• Already included once in this study (can only be included for one treated eye).