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that of Hille 100% survival at 8 years (25 cases) (Falcinelli et al. 2005, Hille
et al. 2006). At our institution, the anatomical results for OOKP performed
in 145 eyes—excluding the second eye in bilateral cases—between 1974
and 2005 were of 68% Kaplan-Meier survival at 8th years and 59% at 18
years post-op (de la Paz et al. 2008). While these lower survival rates might
refl ect the fact that 37% of our patients, live abroad—which could explain
a suboptimal follow-up—the overall very long-term success of OOKP in
theses series is quite remarkable.
The published functional results of OOKP follow a similar pattern,
with more optimistic fi gures in the Falcinelli series compared to ours. They
report a mean VA of 0.69 (Snellen decimal scale) at the last follow-up after
18 years. We found “maximal VA”—defi ned as the best at any point after
the procedure—between 0.8 and 1.0 in 48% of eyes, with an additional 24%
between 0.3 and 0.7. However, Kaplan-Meier functional survival defi ned
as VA ≥ 0.05 was of 50% after 5 years and of 39% after 10 years of follow-
up, leveling to around 20% after more than 30 years (de la Paz et al. 2008).
Using a “VA by Time” index—which averages the best corrected VA at a
particular time after the procedure—we found an increase to 0.33 at 2nd
year followed by a slow decline to 0.28 at 6 years (Michael et al. 2008).
Even these relatively modest results are remarkable considering the initial
condition of these patients.
An analysis of the factors infl uencing the outcomes showed that the
anatomic survival of OOKP at 5 years was similar for all diagnosis except for
OCP with already the poorest results. After 10 years, those with thermal and
chemical burns fared better than those with SJS or trachoma. Surprisingly,
the functional survival (VA ≥ 0.05 decimal) at both 5 and 10 years was
better for SJS compared to burns and OCP. Postoperative complications are
common after any keratoprosthesis procedure and OOKP does not escape
this rule. The most frequent in our series was extrusion of the prosthesis
(28%), followed by retinal detachment (16%), uncontrolled glaucoma (11%),
infection (9%), retroprosthetic membrane (5%) and vitreous hemorrhage
(3%). The effect of these complications on the outcomes is variable, with
as a rule greater impact on the functional than on the anatomic survival.
For example, glaucoma is a major cause of fi nal decrease in VA, although
these cases had the highest rate of anatomical success (90% at 10 years). The
infl uence of age is not very clear; while those above 70 years had the best
10-year anatomical survival, there is a trend to better functional survival
in the younger patients. This could be due to the age-related progression
of either the chronic ocular (glaucoma and retinal/macular problems) or
systemic conditions (de la Paz et al. 2008). The frequent postoperative
complications of OOKP are confi rmed in other series including one recent
from India (Iyer et al. 2010).
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