Bilateral Keratectasia 34 Years after Corneal Transplant.

Abstract

We report the clinical findings of a patient with severe bilateral keratectasia 34 years after a penetrating keratoplasty (PK) in both eyes. An otherwise healthy 67-year-old man complained of deterioration of the eyesight in both eyes over the last 6 months. The patient was diagnosed with bilateral keratoconus at the age of 32 years, and he underwent a bilateral PK. At presentation, visual acuity was 20/200 in the right eye and light perception in the left eye. A Pentacam pachymetric map revealed a central pachymetry of 720 mum in the right eye and of 710 mum in the left eye, as well as an average paracentral pachymetry of 436 and 270 mum in the 9-mm zone in the right and the left eye, respectively. Corneal topography revealed bilateral irregular and asymmetric bowing with generalized steepening and high corneal power. We describe a case of bilateral keratectasia 34 years after PK in a patient who was originally diagnosed with bilateral keratoconus.

Full text

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Case Rep Ophthalmol 2010;1:24–29
DOI: 10.1159/000316919
Published online: July 2, 2010
© 2010 S. Karger AG, Basel
ISSN 1663–2699
www.karger.com/cop


Xavier Valldeperas, MD, PhD, FEBO
Department of Ophthalmology, Hospital Universitari Germans Trias i Pujol
Carretera de Canyet s/n, ES–08916 Badalona (Spain)
E-Mail xvalldeperas @ gmail.com

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Bilateral Keratectasia 34 Years
after Corneal Transplant
Xavier Valldeperasa, b Martina Angib, c Vito Romanod
Mario R. Romanob, e
aDepartment of Ophthalmology, Hospital Universitari Germans Trias i Pujol,
Badalona, Spain; bSt Paul’s Eye Unit, Royal Liverpool University Hospital,
Liverpool, UK; cDepartment of Ophthalmology, Campus Biomedico University,
Rome, dDepartment of Ophthalmology, S. Sebastiano Hospital, Caserta, and
eDepartment of Ophthalmology, Istituto Clinico Humanitas, Rozzano, Italy

Key Words
Bilateral keratectasia · Penetrating keratoplasty · Bilateral keratoconus
Abstract
We report the clinical findings of a patient with severe bilateral keratectasia 34 years
after a penetrating keratoplasty (PK) in both eyes. An otherwise healthy 67-year-old man
complained of deterioration of the eyesight in both eyes over the last 6 months. The
patient was diagnosed with bilateral keratoconus at the age of 32 years, and he
underwent a bilateral PK. At presentation, visual acuity was 20/200 in the right eye and
light perception in the left eye. A Pentacam pachymetric map revealed a central
pachymetry of 720 μm in the right eye and of 710 μm in the left eye, as well as an
average paracentral pachymetry of 436 and 270 μm in the 9-mm zone in the right and
the left eye, respectively. Corneal topography revealed bilateral irregular and asymmetric
bowing with generalized steepening and high corneal power. We describe a case of
bilateral keratectasia 34 years after PK in a patient who was originally diagnosed with
bilateral keratoconus.
Introduction
Keratoglobus is a non-progressive or minimally progressive, non-inflammatory
corneal degeneration defined by a globular protrusion of the cornea with or without
enlargement of the corneal diameter and a generalized thinning mainly in the periphery,
without the presence of neovascularization [1]. The cornea is usually transparent, but
acute corneal edema due to rupture of Descemet’s membrane and perforation, even from
minimal trauma, is the most frequent complication [2]. This rare condition is usually
bilateral and has been associated with several eye conditions, such as blue sclera syndrome
[3], Leber’s congenital amaurosis [4], pellucid marginal degeneration [5], inflammatory

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Case Rep Ophthalmol 2010;1:24–29
DOI: 10.1159/000316919
Published online: July 2, 2010
© 2010 S. Karger AG, Basel
ISSN 1663–2699
www.karger.com/cop


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orbital pseudotumor, chronic marginal blepharitis, and chronic eye rubbing, and it can
also develop following penetrating keratoplasty (PK) [1]. In addition, it has been related
to joint hypermobility and consanguineous parents [6]. Acquired keratoglobus has also
been described in association with vernal keratoconjunctivitis [1], hyperthyroidism [7],
advanced keratopathy (keratoconus), trauma and exophthalmos [8]. The pathogenesis
and the molecular events responsible for the disease expression remain unclear [3], and
there are limited reports of the genetic background of keratoglobus [4].
Case Report
An otherwise healthy 67-year-old man presented with progressive deterioration of vision in both
eyes over the last 6 months. Best-corrected visual acuity (BCVA), using contact lens combined with
spectacle correction, was 20/200 in the right eye (–18.50 dpt sph, –1.50 dpt cyl) and light perception
(–4.00 dpt sph) in the left eye.
The patient was diagnosed with bilateral keratoconus at the age of 32 years, with no associated
connective tissue disorders or other systemic diseases. At that time, BCVA was 20/200 in the right eye
and 20/70 in the left eye, and refraction was –14.00 dpt in both eyes. One year after the keratoconus
diagnosis, the patient underwent a PK in the left eye for a progressive deterioration of the eyesight and
thinning of the cornea. Six years later, another PK was performed in the right eye.
A 6.5-mm diameter keratoplasty was performed in the right eye and a 7.00-mm diameter
keratoplasty in the left eye to include the abnormal cornea. BCVA recovered rapidly to 20/40 in the left
eye and 20/50 in the right eye after the surgeries, and it remained stable until six months before the
patient attended our clinic.
At presentation, slit-lamp examination showed clear corneal buttons (fig. 1), globular protrusion of
the cornea with ectatic profile and midperipheral thinning (fig. 2). Bilateral full-thickness corneal scars,
resulting from the previous PK, were also noted. Vertical and horizontal corneal diameters were 11.0
and 11.6 mm, respectively, in the right eye, and 11.0 and 11.8 mm, respectively, in the left eye.
Intraocular pressure (IOP) was 12 mm Hg in the right eye and 14 mm Hg in the left eye. Anterior
chamber depth was 4.63 mm in the right eye and 5.71 mm in the left eye, and axial length was 33.04 and
35.40 mm, respectively (CineScan ‘S’; Quantel Medical, Bozeman, Mont., USA). No other findings apart
from moderate nuclear lens opacity in both eyes were found in the anterior segment. Fundus
examination revealed myopic changes, including posterior staphyloma and mild chorioretinal atrophy
around the optic disc. After the complete ophthalmological examination, no other cause but the corneal
ectasia could be found to explain the severe vision loss.
Pachymetric maps, using the Pentacam, a Scheimpflug-based imaging system (Oculus Optikgeräte
GmbH, Wetzlar, Germany), revealed a central pachymetry of 720 μm in the right and of 710 μm in the
left eye, as well as an average paracentral pachymetry of 436 and 270 μm in the 9-mm zone, respectively.
The thinnest areas on the temporal side were 290 μm in the right eye and 81 μm in the left eye. These
findings were confirmed by ultrasonic corneal pachymetry (Corneo-GageTM Plus; Sonogage Inc.,
Cleveland, Ohio, USA). Corneal topography (EyeMap version 6.2; CSO, Firenze, Italy) revealed
irregular and asymmetric bowing in both eyes. In addition, generalized bilateral steepening was
observed with high corneal power (fig. 3). The patient underwent a second larger bilateral PK – 9 mm
this time – in an attempt to improve visual acuity. Six months after this second keratoplasty, BCVA was
20/100 in both eyes.
Discussion
We present a case of a patient diagnosed with bilateral keratoconus and treated for this
condition with a PK in both eyes. Thirty-four years later, he presented with decreased
vision and bilateral keratectasia.
The initial diagnosis of bilateral keratoconus 34 years before is to be discussed. If we
believe the diagnosis was right, late keratoconus recurrence on the corneal graft could be
an explanation for the current situation. Increasing astigmatism should have been

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Case Rep Ophthalmol 2010;1:24–29
DOI: 10.1159/000316919
Published online: July 2, 2010
© 2010 S. Karger AG, Basel
ISSN 1663–2699
www.karger.com/cop


26
expected as a sign of late progression of the keratoconus in the host cornea [9], but only a
high spherical refractive error was found, with no astigmatic shift. Moreover, pachymetry
of the corneal button was not reduced (715 and 709 μm), with no central thinning as
would be expected in a keratoconus recurrence. Corneal thinning was observed outside
the graft (436 and 270 μm in the 9-mm zone). Thus, if the patient did not have a
recurrence but a keratoconus, the actual corneal profile could also be secondary to a
severe PK wound thinning, developing many years after a graft. Nevertheless, the
thinning usually observed in this situation is not so severe and not for 360°.
However, a misdiagnosed previous keratoglobus with a secondary keratectasia
generated by a peripheral thinning of the cornea could also be a possible explanation for
the actual corneal ectasia, which is more plausible for us. The diameter of the transplant
would have been sufficient for a keratoconus, but was not large enough to stabilize the
graft-host junction in a keratoglobus. The small-diameter PK significantly improved the
patient’s visual acuity, probably secondary to the flattening effect of the graft rather than
to the resolution of his underlying condition. The mechanism of production of this
globular corneal contour is not totally clear, but wound weakness in the area of the graft-
host junction could be a possible cause. This idea was already stated by Cameron [1], who
reported a case of limbus-to-limbus thinning and globular contour in a patient who
underwent two PK in the same eye. He suggested that in most cases of keratoglobus, the
marked mid-peripheral thinning could represent the relative weakness of this area and be
the main predisposing factor for developing such a contour. In the patient described by
Cameron, though, the thinning involved both the central and peripheral cornea and the
IOP was 40 mm Hg, which could have contributed to the global ectasia. In our case, the
IOP was normal and the mechanical stress of the grafts was not especially high.
In summary, we present a case with an end-stage evolution of a corneal ectasia and
severe bilateral visual impairment, many years after a PK in both eyes. Whether this
situation was originally caused by a keratoconus or by a misdiagnosed keratoglobus with
secondary keratectasia cannot be cleared at the present time. Nevertheless, this new
condition was satisfactorily treated with larger PK in both eyes.

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Case Rep Ophthalmol 2010;1:24–29
DOI: 10.1159/000316919
Published online: July 2, 2010
© 2010 S. Karger AG, Basel
ISSN 1663–2699
www.karger.com/cop


27
Fig. 1. Slit-lamp photograph showing clear corneal button in the right eye, taken when the patient was
admitted with complaints of decreased visual acuity.



Fig. 2. Picture showing the left (a) and right (b) eye cornea profile with severe corneal ectasia. Vertical
and horizontal diameters were 11.0 and 11.6 mm in the right eye, and 11.0 and 11.8 mm in the left eye,
respectively.

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Case Rep Ophthalmol 2010;1:24–29
DOI: 10.1159/000316919
Published online: July 2, 2010
© 2010 S. Karger AG, Basel
ISSN 1663–2699
www.karger.com/cop


28
Fig. 3. Pentacam anterior corneal curvature map for the right eye (a) and the left eye (b), revealing
irregular bowing with generalized steepening and high corneal power.

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Case Rep Ophthalmol 2010;1:24–29
DOI: 10.1159/000316919
Published online: July 2, 2010
© 2010 S. Karger AG, Basel
ISSN 1663–2699
www.karger.com/cop


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