Modified Osteo-Odonto Keratoprosthesis (MOOKP) in patients with severe anterior segment disease: Our Hong Kong Experience

Bone – Tooth Cornea replacement 骨齒人工角膜

Ben Lam, Srinivas Rao, Alvin Young, Lulu Cheng,Dennis Lam Hong Kong Eye Hospital Department of Ophthalmology and visual science /CUHK (no financial interest)

Purpose

To evaluate the efficacy and safety of Modified Osteo-Odonto Keratoprosthesis (MOOKP) in Hong Kong patients with severe anterior segment disease.

Methods

Retrospective review of all nine patients with MOOKP performed at Hong Kong Eye Hospital from June 2005 to Oct 2007. All patients had poor vision bilaterally as a result of chemical injury, ocular cicatricial pemphigoid (OCP) or multiple corneal graft failure.

Methods

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.

Methods

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

Methods

Outcome measures included post-operative visual acuity complications such as glaucoma, retinal detachment and wound-related problems

Age 1 M/37 Primary disorder Chemical injury Pre op VA HM Refraction Postop VA +4.00 DS 0.7

Complication 2 M/75 Chemical injury 3 4 5 6 M/32 M/25 M/47 M/63 Chemical injury Chemical injury Chemical injury OCP LP PR accurate LP PR accurate HM +3.50 DS LP PR accurate LP PR accurate +3.00 DS +4.50 DS LP 0.1

NLP 0.5

0.4

Choroidal Effusion, VH Pale disc 0.9

Phthisis RD, pale disc Lash touch cylinder 7 F/73 Multiple Graft failure HM +4.25 DS 0.7

8 9 M/63 M/67 Chemical Injury OCP HM LP PR accurate +4.00 DS +4.00 DS 0.4

0.6

Overgrowth of mucosa

Results

The mean patients ’ (ranges 25 – age was 53.6 years 75 years).

Six patients suffered from chemical burn, two from OCP and one had history of multiple corneal graft failure. The mean post-operative follow-up was 18.4 months (range 6- 28 months).

Results

The pre-operative best corrected visual acuity (BCVA) ranged from hand movement to light perception Post-operative Snellen BCVA ranged from 0.4.to 0.7 except for three eyes.

Results

One eye developed choroidal effusion and vitreous haemorrahge. One eye developed retinal detachment and pale disc .The visual acuity was light perception and no light perception respectively. One eye also developed overgrowth of the mucosa over the cylinder which required excision. Two eye had pale discs post operatively compromising the visual potential

Conclusion

Despite the complex nature of the operation and possible complications MOOKP offers the hope of visual improvement for patients with severe anterior segment disease. Future studies with longer follow-ups to evaluate its efficacy and safety are warranted.