Beginning in 1949 with the pioneering work of Jose Barraquer, there has been an interest in using natural corneal tissue to change the refractive properties of the eye. In recent years, non-allogenic, synthetic corneal implants have received marketing approval in the United Stated and Europe for refractive purposes. Although synthetic implants are made of biocompatible materials, they are not equivalent to an allogenic implant in terms of biocompatibility.
The Allotex TransForm lenticule is a piece of acellular cornea, sterilized with electron beam radiation and shaped to a particular shape using a laser. The availability of precise laser shaping systems and sterile corneas are the key factors that make the use of allogenic implants possible.
The TransForm lenticule is applied under a femtosecond created corneal flap on a stromal bed. The goal is to enhance the visual performance of the patient with a material that is 100% biocompatible and precisely shaped for the
individual’s needs.

The Allotex TransForm lenticule is biocompatible, highly precise, and shelf stable at room temperature. It is formed lenticule comprised of sterile allogenic corneal tissue designed to alter the shape of the anterior surface of the cornea, thereby adjusting the point of focus on the retina. The tissue derives from human corneas, procured under strict ethical standards from an Eye Bank Association of America (EBAA) approved eye bank. After minimal processing by the eye bank the corneas undergo a validated electron beam (e-beam) sterilization process and are then transferred to Allotex for further processing.
The lenticules are designed to be placed directly on top the recipient’s stroma which has been exposed by the creation of a thin, femtosecond laser created flap. After placement the flap is the laid down over the TransForm lenticule and smoothed in the normal fashion. The final shape, after laser sculpting, is 2-3.5 mm in diameter, with a central thickness of 15-25 microns. The diameter is such that the patient is expected to have improved near and intermediate vision and will also retain distance vision from the rays entering the pupil around the periphery of the TransForm lenticule .
Tissue
VisionGift, the provider of the Allotex allogenic tissue, procures, cleans and sterilizes cornea for shipment to Allotex. Terminal sterilization is performed by electron beam.
References
- Biowski R, Homolka P, Barisani-Asenbauer T, Baumgartner I, Husinsky W, Kaminski S, Lametschwandtner A, Muss W, Grabner G. Corneal lathing using the excimer laser and a computer-controlled positioning system. J Refract Surg. 2000 Jan-Feb;16(1):23-31.
- Ganesh, S., Brar, S. & Rao, P. A. Cryopreservation of extracted corneal lenticules after small incision lenticule extraction for potential use in human subjects. Cornea. 33, 1355–1362 (2014).
- Biological corneal inlay for presbyopia derived from small incision lenticule extraction (SMILE) https://www.nature.com/articles/s41598-018-20267-7
- Busin M, Nussgens Z. Epikeratophakia. Fortschr Ophthalmol. 1990;87 Suppl:S219-23. Busin M, Schmidt J, Koch J. Physiologic analysis of corneal healing after epikeratophakia. Ophthalmology. 1992 Mar;99(3):415-7.
- Busin M, Spitznas M, Hockwin O. Evaluation of functional and morphologic parameters of the cornea after epikeratophakia using prelathed, lyophilized tissue. Ophthalmology. 1990 Mar;97(3):330-3. Cahill M, Condon P, O’Keefe M. Long-term outcome of epikeratophakia. J Cataract Refract Surg. 1999 Apr;25(4):500-7.
- Food and Drug Administration Summary of Safety and Effectiveness for P120023 (http://www.accessdata.fda.gov/cdrh_docs/pdf12/P120023B.pdf) Food and Drug Administration Summary of Safety and Effectiveness Device for P150034 (http://www.accessdata.fda.gov/cdrh_docs/pdf15/P150034B.pdf) Ganesh S, Brar S, Rao PA.
- Cryopreservation of extracted corneal lenticules after small incision lenticule extraction for potential use in human subjects. Cornea. 2014 Dec;33(12):1355-62.
- Greenbaum A, Kaiserman I, Avril I. Long-term reversibility of epikeratophakia. Cornea. 2007 Dec;26(10):1210-1. Kang J, Cabot F, Yoo SH. Long-term follow-up of epikeratophakia. J Cataract Refract Surg. 2015 Mar;41(3):670-3.
- McDonald MB, Klyce SD, Suarez H, Kandarakis A, Friedlander MH, Kaufman HE. Epikeratophakia for myopia correction. Ophthalmology. 1985 Oct;92(10):1471-22.
- McDonald MB, Kaufman HE, Aquavella JV, Durrie DS, Hiles DA, Hunkeler JD, Keates RH, Morgan KS, Sanders DR. The nationwide study of epikeratophakia for myopia. Am J Ohthalmol. 1987 Mar 15;103(3 Pt 2):375-83.
- Morgan KS, Beuerman RW. Interface opacities in ng of donor tissue for epikeratophakia. Br J Ophthalmol. 1994 Nov;78(11):863-70.
- Zhao J, Sun L, Shen Y, Tian M, Yao P, Zhou X. Using donor lenticules obtained through SMILE for an epikeratophakia technique combined with phototherapeutic keratectomy. J Refract Surg. 2016 Dec 1;32(12):840-845.
- Zhou Y, Zhang J, Zheng Y, Liu Q, Wei W, Wang N. The early clinical efficacy of allogeneic corneal lens inlays in correction of hyperopia. Zhonghua Yan Ke Za Zhi. 2015 Sep;51(9):683-8.epikeratophakia. Arch Ophthalmol. 1986 Oct;104(10):1505-8.
- Sun L, Yao P, Li M, Shen Y, Zhao J, Zhou X. The safety and predictability of implanting autologous lenticule obtained by SMILE for hyperopia. J Refract Surg. 2015 Jun;31(6):374-9.
- Swinger CA. Comparison of results obtained with keratophakia, hypermetropic keratomileusis, intraocular lens implantation, and extended-wear contact lenses. Int Ophthalmol Clin. 1983 Fall;23(3):59-74.
- Swinger CA, Wisnicki HJ. Freezing increment in keratophakia. Cornea. 1985-1986;4(4):225-8.
- Utine CA, Tzu JH, Akpek EK. Lamellar keratoplasty using Gamma-irradiated corneal lenticules. Am J Ophthalmol 2011;151:170-174.
- Werblin TP, Kaufman HE. Epikeratophakia: the surgical correction of aphakia. I. Lathing of corneal tissue. Curr Eye Res. 1981;1(3):123-9.
- Werblin TP, Kaufman HE. Epikeratophakia: the surgical correction of aphakia. II. Preliminary results in a non-human primate model. Curr Eye Res. 1981;1(3):131-7.
- Werblin TP, Kaufman HE, Friedlander MH, Granet. Epikeratophakia: the surgical correction of aphakia. III. Preliminary results of a prospective clinical trial. Arch Ophthalmol. 1981 Nov;99(11):1957-60.
- Werblin TP, Kaufman HE, Friedlander MH, McDonald MB, Sehon KL. Epikeratophakia-the surgical correction of aphakia. Update 1981. Ophthalmology. 1982 Aug;89(8):916-920.
- Werblin TP, Blaydes JE. Epikeratophakia: existing limitations and future modifications. Aust J Ophthalmol. 1983 Aug;11(3):201-7.
- Young RD, Armitage WJ, Bowerman P, Cook SD, Easty DL. Improved preservation of human corneal basement membrane following freezing