Keratoprosthesis is a surgical procedure where an artificial cornea replaces a severely damaged or diseased natural cornea. It involves implanting an artificial optical cylinder made of clear plastic materials inside the eye with a supporting flange or skirt outside the eye. The Boston KPro is the most commonly used keratoprosthesis device and comes in Type 1 and Type 2 models for different clinical situations. The Osteo-Odonto KPro is a more complex multi-stage procedure that uses the patient's own tooth and surrounding bone to support an artificial cornea for patients with severe dry eye conditions. Keratoprosthesis surgery aims to restore sight for patients with corneal blindness when traditional corneal transplant is not possible or

1. KERATOPROSTHESIS
Presented by- Dr samarth mishra

2. Keratoprosthesis=artificial corneaKeratoprosthesis=artificial cornea
(kerato=cornea; prosthesis=artificial(kerato=cornea; prosthesis=artificial
substitute)substitute)
 The idea of artificial cornea was first proposed in
1789 by French ophthalmologist Guillaume Pellier
de Quengsy.
 The first reported human KPro surgery with a
quartz crystal implant was performed by Nussbaum
in 1855
 1950- Stone & Herbert – noted PMMA(poly methyl
methacrylate) splinters embedded in corneas of
pilot of World War II were well tolerated.

3. KERATOPROSTHESISKERATOPROSTHESIS
 Keratoprosthesis is a surgical procedure where a severely damaged
or diseased cornea is replaced with an artificial cornea.
 Keratoprotheses are made of clear plastic with excellent tissue
tolerance and optical properties. They vary in design, size and in the
implantation techniques.
 Keratoprosthesis restores sight – eye with damaged cornea by
means of a special tube that acts as a “periscope’’ from the eye to
outside world.
 Keratoprosthesis extend both inside the eye and outside into the
environment.
 It provides a tunnel vision.
 Extent of visual field increases with increase in diameter and
decreases with increasing length of the optical cylinder.

4. DESIGN & MATERIALSDESIGN & MATERIALS
 Keratoprosthesis –consists of an optical cylinder & a
supporting flange.
 Devices usually consist of a porous outer skirt element
joined to rigid polymethylmethacrylate lens.
 Materials used for optical cylinder-
1. PMMA(choyce & boston keratoprosthesis)
2. Dacron( pintucci keratoprosthesis)
3. Polycarbonate(champagne cork keratoprosthesis )
4. Hydroxy-apatite ( leon – barraquer Kpro)
5. Hydrogel( alpha cor keratoprosthesis) &
6. Polyurathane ( seoul keratoprosthesi)
 PMMA – most widely used material for optical
cylinder & never reported as a cause of failure.

5. SUPPORTING FLANGE made up of :SUPPORTING FLANGE made up of :
1. METHACRYLATE
2. TEFLON
3. DACRON MESH
4. POLYCARBONATE
5. TOOTH & BONE( OSTEO-ODONTO KPRO)
6. CARTILAGE(CHONDRO KPRO) OR
7. NAIL ( ONYCHO KPRO)

6. CLASSIFICATION OFCLASSIFICATION OF
KERATOPROSTHESIS DESIGNS:KERATOPROSTHESIS DESIGNS:
 NON PENETRATING ( INTRALAMELLAR )
 PENETRATING
 ANTERIOR
 POSTERIOR
 PERFORATING
 INTRALAMELLAR
 ANTERIOR
 Cardona through and through keratoprosthesis
 Ceramic keratoprosthesis
 Dohlman keratoprosthesis
 Osteo odonto keratoprosthesis
 Boston keratoprosthesis
 Champagne cork keratoprosthesis
 POSTERIOR
 Nut and Bolt keratoprosthesis

8. Keratoprosthesis
suitable for severe
dry eye with absent
tear function-
Osteo odonto
keratoprosthesis
Boston
keratoprosthesis
type II
Keratoprosthesis
indicated in eyes with
some residual tear
function are
classified as wet
eyes-
Champagne cork
Pintussi
Boston type I
Alpha cor
keratoprosthesis

10. Keratoprosthesi can be divided into temporary andKeratoprosthesi can be divided into temporary and
permanent depending on indicationpermanent depending on indication
Temporary device used intra operatively to aid in
visualization and removed following surgery.
 Indication include
 Severe ocular trauma for anterior & posterior segment
reconstruction
 Cataract extraction
 Modified triple procedure
 Vitreo retinal surgery in case of corneal opacity or ocular
trauma
 Combined PK &vitreoretinal surgery
 Ex- Eckardts keratoprosthesis, Landers Foulk & Landers
wide field lenses
Permanent keratoprosthesis- used to treat
patients with severe corneal disease where corneal
transplantation is inappropriate or has repeatedly failed.

11. INDICATIONS &INDICATIONS &
CONTRAINDICATIONSCONTRAINDICATIONS
Keratoprosthesis indicated in patients with bilateral corneal
blindness who have little or no chance of success with a
standard corneal graft.
Indicated in medical conditions like
Multiple graft failure
Graft failure with chronic edema
Corneal dystrophy
 Stevens-Johnson syndrome
 Ocular cicatricial pemphigoid
 Ocular burns (acid and alkali, thermal)
 and other conditions with poor prognosis with traditional PKP
Procedure of last resort
- to give at least navigational vision
- not done if BVA both eyes > or= CF

12. Indications:Indications:
Lacrimal choristoma
Failed corneal graft HZO/ neurotrophic keratopathy

13. STEVEN JOHNSONS SYNDROMES
Vascularized cornea
Central KPro in a patient with Acid burns
8yrs post-op VA 6/36

14. Contraindications
• Patients who are happy and managing with their level of
vision
•children under the age of 17,
• eyes that have no perception of light,
•evidence of phthisis,
•advanced glaucoma or
• irreparable retinal detachment should be excluded.
Suitable candidates have to understand that the surgery can
be prolonged—they may require multiple procedures—and
that there is a significant risk of serious complications
including loss of the eye.
The patient must be able to commit to life-long follow-up, and
not have unreasonable expectations of outcome and
cosmesis.

15. Preoperative assessmentPreoperative assessment
Eye undergoing keratoprosthesis surgery should
be free from initial insult of injury,physical
/chemical , active inflammation or infection.
Intraocular pressure should be adequately
controlled with no evidence of glaucomatous
damage to optic nerve head.
A good visual potential must be elicited with aid
of light projection, pupillary responses,
ultrasonography of posterior segment &
electrodiagnostic tests.

16. The commonly used ones are
BOSTON KPRO(TYPE 1 AND 2)
The Boston Type I Kpro is the most widely used device.
The Boston Type II Kpro may be indicated in patients
with severe ocular surface disease, poor ability to maintain
a moist ocular surface, and forniceal foreshortening with
inability to wear a contact lens
ALPHA-COR KPRO
AlphaCor Kpro is indicated in patients with failed grafts
due to corneal allograft rejection
OSTEO-ODONTO KPRO(OOKP)
OOKP like theBoston Type II Kpro, is reserved for end-
stage ocular surface
disease as a last resort

17. BOSTON KERATOPROSTHESISBOSTON KERATOPROSTHESIS
Boston Keratoprosthesis is the innovation
and design of Professor Claes H. Dohlman
FDA approval 1992
types 1 and 2
made from poly methyl methacrylate
(PMMA).
Most commonly used type 1

18. 2 Types
◦ Type 1:- More
commonly used.
Used in eyes that
have sufficient
wetting function to
maintain the corneal
tissue in which the
Kpro is placed.
◦ Type 2:- Used in
very dry eye with
minimal or no tear
production.
Boston Keratoprosthesis TypesBoston Keratoprosthesis Types

19. PartsParts
collar button design
 There is a front plate and
back plate sandwiching a
fresh donor corneal graft
Titanium locking ring is
used to secure the front And
back plates and corneal
complex to prevent Any
Inadvertent Unscrewing of
the complex.

20. Type 1Type 1
The typical anterior surface power of this device is 43–44
dioptres.
Aphakic eyes require a variety of powers depending on
the axial length

21. Type 2Type 2
The type 2 device is of a similar design,
with an added anterior cylinder that
protrudes through a permanently closed
upper eyelid, and is used in end-stage dry
eye
Back plates holes are important to allow
the nutrients to reach the graft
keratocytes from the aqueous

22. surgerysurgery
Superficial keratectomy of 8.5 mm of
donor cornea then a 3mm central punch
done
The donor button is then placed over
the stem of the front plate and the back
plate is slid into place on top of this
without screwing or turning.
 A titanium locking ring is then pushed
onto the remaining exposed stem until
an audible snap is heard

23. The recipient cornea is then trephined as
for conventional PKP (trephine diameter
0.5 mm less than donor trephine size).
The donor graft with the KPro is then
sutured in place with interrupted 10–0
nylon, using the same technique as a
standard PKP.
Surgery usually concludes with the
intracameral injection of 0.4 mg
dexamethasone
Conclusion with the application of a soft
contact lens
Post op steroid E/D ,antibiotic E/D used
Post op F/U at 1,2,4 wks,then monthly
Each visit IOP and VA noted and soft
contact lens changed

25.  Finally, a soft contact lens , plano power, is placed as
a bandage lens.
 All patients received lifelong prophylactic antibiotics:
moxifloxacin 0.5% , Vacomycin fortified drops
(25mg/ml) qid, Prednisolone Acetate 1% and Tears
Naturale Free .

27. OSTEO-ODONTO KPRO (OOKP)OSTEO-ODONTO KPRO (OOKP)
Osteo-odonto-keratoprosthesis
(OOKP) (also known as "tooth in eye"
procedure.
It includes removal of a tooth from the
patient or a donor. After this, a lamina of
tissue cut from the tooth is drilled and the
hole is fitted with optics. The lamina is
grown in the patients' cheek for a period
of months and then is implanted upon the
eye

28. MODIFIED OSTEO ODONTOMODIFIED OSTEO ODONTO
KPRO(MOOKP)KPRO(MOOKP)
The OOKP was first described by Strampelli in
1963
Later modified (MOOKP) by falcinelli and coll
It uses the patient’s own tooth root and
surrounding alveolar bone to support a centrally
cemented optical cylinder.
Multi staged procedure, sx in mouth and eye
PRINCIPLE
use of a wide single rooted tooth with surrounding
alveolar bone acts as carrier for a PMMA optical
cylinder, which is covered by buccal mucous
membrane,

31. Pre op assesmentPre op assesment
detailed history
Previous surgical interventions
An inaccurate projection of rays (PR) is not
a contraindication
Intraocular pressure is usually assessed by
digital tonometry
 Oral assessment includes assessment of
oral and dental hygiene and state of buccal
mucosa.
spiral CT scan of canines is carried out for
selection of a suitable tooth with the
assistance of an oromaxillofacial surgeon

32. MethodsMethods
In contrast to classic
OOKP, Our MOOKP
consists of 3 stages.
The first stage involves
the removal of iris and
lens, as well as the
preparation of the osteo-
dental lamina complex.

33. MethodsMethods
The second stage
involves the
preparation of
buccal mucosal
surface
Third stage
involves
implantation of
complex.

34. STAGE 1A
superficial keratectomy
fibrovascular pannus removal
intracapsular cataract extraction
anterior vitrectomy
total iridectomy
Complete removal of these structures is
done to reduce the possibility of
postoperative glaucoma and formation of
retroprosthetic membranes.

35. STAGE 1B
done usually 6 weeks after stage IA
full thickness mucous membrane graft (MMG) harvested from
the buccal mucosa.
The extent of MMG should be extend from upper to lower
fornix and measures around 3-4 cm in diameter.
MMG is sutured over damaged cornea at insertion of 4 recti
muscles and sclera In four quadrnts with 6.0 vicryl
It has stem cells,high proliferating Capacity and adapted to high
Bacterial load

36. STAGE 1C
Involves preparation of the osteo dental acrylic Lamina
(ODAL)
A single rooted tooth, preferably the upper canine is chosen
for preparation of the lamina.
The tooth with the surrounding alveolar bone is extracted.
Then sliced sagitally and Central hole is drilled
customized PMMA optical cylinder is cemented with acrylic
resin
ODAL is then placed in the subcutaneous pouch in the orbito
zygomatic area for next 3 months to develop vascularization
and to promote the growth of connective tissue.

37. STAGE 2
This is performed 3 months after stage IB+IC
ODAL is dissected off from the subcutaneous pouch and
examined for its integrity prior to proceeding with ocular surgery
The central cornea is trephined according to the posterior
diameter of the cylinder.
ODAL is placed with the cylinder centered over the corneal
trephination and sutured.
The MMG is finally reflected back on the lamina with a central
trephination through which the anterior cylinder protrudes out

38. POST OP MANAGEMENT
•Perioperatively, systemic and topical
antibiotics are administered.
•Systemic steroids and antiglaucoma
medication are also prescribed
Visual acuity, refraction, digital tonometry,
fundus, optic nerve status and visual fields
should be checked at each follow up.
The health of the mucous
membrane,protrusion and stability of the
optic cylinder should be looked for.

39. ALPHA COR KPROALPHA COR KPRO
The AlphaCor developed from the Chirila Kpro at
the Lions Eye Institute in Western Australia, first
implanted in human eyes in 1998 and receiving FDA
approval in 2003.
Manufactured from a single biocompatible polymer,
poly hydroxyethyl methacrylate (pHEMA)
two zones, a clear central optical core and an
opaque spongy skirt, made by polymerizing
the pHEMA under conditions of differing water
content
Interpenetrating polymer network (IPN) –
junction between the skirt and central optic
and is a permanent bond
Refractive Power close to that of human cornea .

40. ALPHA-COR KERATOPROSTHESISALPHA-COR KERATOPROSTHESIS
FDA-approved type of synthetic cornea
measuring 7.0 mm in diameter and
0.5 mm in thickness.
main advantages of synthetic corneas are
that they are biocompatible, and the
network between the parts and the device
prevents complications that could arise at
their interface.

42. PRINCIPLE
The ability of the outer skirt to be colonized by
invading keratocytes resulting in integration of
the device with surrounding tissues
INDICATIONS
Patients should have adequate tear production
as assessed by the unstimulated Schirmer test
with a value of at least 50% of normal
VA from <6/60 to light perception
previous failed grafts with a poor chance with
further PKP
Functioning retina
absence of evidence of advanced
glaucomatous optic neuropathy or well-
controlled glaucoma on treatment.

43. Surgical procedure-- 2 stageSurgical procedure-- 2 stage
procedureprocedure
STAGE 1
•360° conjunctival peritomy
debridement of the corneal epithelium
superior half of the cornea is dissected into two
layers, superficial and deep, each of about 50%
thickness, through a superior paralimbal 180°
incision
extended to form a pocket in the inferior cornea
superficial corneal flap is then reflected inferiorly to
expose the deep cornea, to allow trephination of the
central posterior lamella with a 3.5 mm disposable
trephine to enter the anterior chamber
The AlphaCor is placed between the two layers
within the pocket, centred over the posterior
lamellar opening
The superficial flap is then replaced and sutured at
the limbus with interrupted 10/0 nylon.

44. STAGE 2
•2 months after Stage I
•tissues superficial to the AlphaCor optic (anterior corneal
lamella) are removed to expose the optical zone.

45.  Following trephination and removal of the host
cornea, manual extracapsular cataract extraction
is performed via an open-sky technique with
placement of a plano intraocular lens.
COMBINED KERATOPROSTHESIS PLACEMENT,
CATARACT EXTRACTION, AND IOL IMPLANTATION

46. The pre-assembled keratoprosthesis is
sutured into position with interrupted bites
using 9.0 nylon suture.

47. SINGH-WORST KPROSINGH-WORST KPRO
 Designed and developed in collaboration
with Dr. Jan Worst in Netherlands and Dr.
Daljit Singh in India.
 Champagne-Cork Design for better stability.
 one piece polycarbonate device
 anterior surface has a diameter of 6.0mm
 Shaft end diameter 4.5mm. Neck diameter
3.0 mm.
 The flange has 8 equidistant holes near the
margin.
 Anticonical shape –creates a valve on the
cornea
 Steel suture fixation on equatorial sclera
preventing extrusion.

48. Stanford Keratoprosthesis :-
◦ Kpro is based on a mechanically enhanced
Hydrogel called Duoptix
◦ It supports the growth of epithelial cells.
◦ Surrounding the optic is a microperforated rim
designed to promote peripheral tissue
integration
Collagen Based Keratoprosthesis
◦ Designed to mimic the extra cellular Matrix of
corneal stroma
Modified Keratoprosthesis Biomaterials
with bio active factors
Recent AdvancesRecent Advances

49. COMPLICATIONSCOMPLICATIONS
MELTS AND EXTRUSION
INFECTIOUS ENDOPHTHALMITIS
GLAUCOMA
RETRO PROSTHETIC MEMBRANES
RETINAL DETACHMENT
OTHERS

50. MELTS AND EXTRUSIONMELTS AND EXTRUSION
Melts tends to occur at the base of Boston
kpro
USG and anterior segment OCT are helpful in
detection and f/u of corneal thinning around
kpro
Any leak on siedels test, USG to be done to
see choroidal effusion
If melts are seen then replace the whole thing
with fresh graft and put new kpro’
In MOOKP, resorption of buccal mucosa can
occur,new graft can be placed
Resoprtion of osteo odonto lamina can
occur,serial CT scan yearly
If much resorption of dentine has occurred
entire thing should be replaced

52. INFECTIOUSINFECTIOUS
ENDOPHTHALMITISENDOPHTHALMITIS
Dreadful complication
following kpro sx
Often evidence of leak
seen
Rx includes leak
repair,i/vit tap,injection
of antibiotics and topical
antibiotics
Fungal infection
suspected change
contact lens and give
topical amphotericin and
systemic anti fungals
required

53. GLAUCOMAGLAUCOMA
Single most serious complication following
sx leading to irreversible loss of vn
D/T chronic low grade
inflamman,progessive angle
closure,anterior displacement of iris have
been implicated
Topical rx is effective in pts with boston
type 1 kpro
systemic rx can be used with boston type
2 and MOOKP
Tube shunts and endoscopic
cyclophotocoagulation have been
succesfully used with all types of kpros

55. RETRO PROSTHETIC MEMBRANESRETRO PROSTHETIC MEMBRANES
 Most commonly reported
 Occurs in 25-64% of pts in 1 yr follow up
 These fibrous membranes originate from activated host
stromal cornea cells that migrate through gaps in the
posterior graft–host junction
 RPM formation seems to be more prevalent in individual
with chronic inflammation such as autoimmune diseases
and uveitis
 Development of titanic back plates have reduced incidence

56. Treatment
Nd yag capsultomy following by steroids in 90% cases
If membrane thick,leathery and vascularised,sx
management
For boston kpro vit+membranectomy can be performed
However removal of prosthesis and repacement with new
one is preferred

57. RETINAL DETACHMENTRETINAL DETACHMENT
Most common posterior segment complication
with an incidence of 16.9 %
Surgical rx with buckle or vitrectomy is
performed
achievement of anatomic success is limited by
the presence of chronic retinal scarring or
proliferative vitreo retinopathy (PVR) and visual
outcomes tend to be worse in these cases
Choroidal detachments can also develop in eyes
with KPro, in as many as 17 % of patients

58. MOOKP

59. Thank youThank you