Table 1.
Historical kertaoprostheses
| Keratoprostheses
| ||
|---|---|---|
| Author (year) | Materials and design | Summary |
| Pellier de Quengsy (1789)14 | Silver-rimmed convex glass disk | It is considered the first design of KPros, but no account of implantation was mentioned. |
| Nussbaum (1853)14,15 | Glass device in collar-stud design | Nussbaum performed heroic experiments on himself by implanting wood, glass, iron, copper, and other materials and noted that glass was non-irritable. He implanted his device in rabbits and humans, which was retained for 3 years and 7 months, respectively. |
| Heuser (1860)16 | Quartz | Heuser implanted a device made of quartz in a blind girl, which was retained for 6 months with good visual recovery. |
| Abbate (1862)16 | Glass disk with surrounding skirt made of rubber and casein | Abbate developed a KPro with the skirt made of natural polymers and the optic with glass. He implanted it in animals, which was extruded in a short time. Although failed, his experiments emphasized the importance of integration of skirt into the eye. |
| Salzer (1900)16 | Quartz disk with platinum ring and flanges | One of the successful early models of KPro that lasted up to 1 year in humans. Salzer made the observations that the optic should be lighter than glass and prosthetic rim should be made of a bio-integrable material. |
| Stone (1953–1958)17,18 | PMMA disk | Perforated disks implanted into the corneal lamellae were retained for more than 3 years. |
| Cardona (1969)19 | PMMA – nut and bolt | It was a widely used KPro model. The PMMA skirt is positioned retrocorneally, which forms the nut, and the threaded optic makes up the bolt. Optic was elongated and could be adjusted in length by rotation through the threading so that it can stay projected beyond conjunctival surface. The optic was detachable, thus it facilitated the treatment of retroprosthetic membrane. |
| Choyce (1967–1978)20 | Perspex CQ – one-piece and two-piece designs | This device was similar to Cardona KPro with a longer core, but was implanted in intralamellar or penetrating fashions. With the initial KPro devices, skirt was implanted first followed by insertion of the threaded optic at a later stage. The implant was covered by either corneal or sclero-corneal graft. The later models were made in a single-piece design and were implanted in two stages. In the first stage, the device was implanted into the eye having the optic covered by corneal tissue. After a period of maturation, the optic was exposed by excision of the overlying tissue. Lens extraction, iridectomy, and core vitrectomy were also performed. |
| Dohlman (1974)21 | PMMA collar button | It consists of one front and one back plate made of PMMA. The front plate contains the optical stem. The back plate was made of black PMMA in some devices. In preliminary models, the back plate was fused to the front plate by using methylene chloride. In later models, the back plate was threaded to the optic. The device was first inserted into a full-thickness donor cornea through a central hole in the cornea. Then the corneal button along with device is sutured to the host cornea similar to keratoplasty. |
| Reudemann (1974)22 | Silicone-satellite KPro | This interesting KPro was made of a satellite-shaped optic having a Dacron skirt glued to its sides. The implant was inserted through a limbal incision with the broader side of the optic positioned inside the anterior chamber and the smaller portion of the optic pushed out through a central corneal opening until the Dacron skirt adheres to the cornea. Eventually a fibrotic membrane develops and holds the device against the cornea. Sutures were not used to secure the device. |
| Cardona (1983)23 | Through and through | A peripherally pigmented PMMA optical cylinder, intended to reduce the glare, was carried on a Teflon skirt. The cylinder was inserted through the cornea, whereas the skirt was anchored to the sclera. Normally, the complex was reinforced with Dacron and supported by donor sclera or autologous tissues like periosteum or eyelid skin (after removing tarsal plate and orbicularis and fascia). Device extrusion rate was 25%.23 |
| Girard (1983)24 | Modified Cardona’s nut and bolt with Dacron or Proplast skirt | Cardona’s nut-and-bolt principle was applied to this device, but the skirt material was taken from Dacron or Proplast. Surgical technique was improved by performing iridectomy, lens removal, and core vitrectomy. Prosthesis was covered with Tenon’s capsule and conjunctiva. The optic was exposed after 3 months by excision of the conjunctiva. Device extrusion was reduced to 10%, but other complications remained.24 |
| Polack (1983)25 | Ceramic (optic and skirt made of aluminum oxide–corundum) | The skirt and optic for this epicorneal device were made of ceramic. The principle of the device is to rest the skirt on the cornea and pass the threaded optical cylinder through the central hole (threaded) of the skirt and also cornea. Lens extraction, iris removal, and generous vitrectomy were performed. The entire device was covered with periosteum or Tenon’s capsule and conjunctiva for 1 week or 2 weeks, after which, by excising the overlying tissue, the optic is exposed. In some cases, the device was also implanted through the lids. |
| Caldwell (1997)26 | PTFE skirt with polyurethane elastomer optic | The skirt was made of a six-pronged porous PTFE polymer (Gore-Tex), which was inserted into the intralamellar corneoscleral pocket. |
| Worst–Singh–Andel (1995)26,27 | Champagne cork KPro (optic made of glass or polycarbonate) | It is a collar-stud device containing an anterior plate connected to a progressively enlarged cone-shaped optic. The optic is inserted through the central corneal aperture. The intraocular pressure helps to press the optic against the cornea, thus creating a seal. The external plate contains fenestrations, through which steel wires are passed through to anchor the device to the sclera. Their study had poor follow-up results.26 Singh implanted the device in the nasal paralimbal sclera, and also used nylon sutures to anchor the device to the rectus muscles.27 |
| Pintucci (1995)28,29 | Dacron skirt with elongated PMMA optic | Dacron fabric capable of biocolonization was incorporated into a medical-grade PMMA optical cylinder. The device is implanted in two stages. In the first stage, the ocular surface of the diseased eye is prepared, keratinized tissue is removed, and a patch of buccal mucosa is grafted, which forms the new ocular surface. In the same sitting, the device is implanted into the submuscular pouch of the contralateral lower lid for connective tissue ingrowth. Two months later, in the second stage, the device is extracted from the submuscular pocket and implanted into the eye under the buccal mucosa. The iris and lens were removed during this procedure. The optic projects through an opening in the buccal mucosa. The authors claim favorable results on a 15-year follow-up with Pintucci KPro.29 |
Abbreviations: KPro, keratoprosthesis; PMMA, polymethylmethacrylate; PTFE, polytetrafluoroethylene.