Penetrating Keratoplasty In Brittle Cornea Syndrome: Case Series And Review Of The Literature

Brittle Cornea Syndrome (BCS) is a rare autosomal recessive connective tissue disorder with ocular manifestations often associated with extraocular involvement; corneal thinning, blue sclera, keratoconus, keratoglobus, high myopia and irregular corneal astigmatism are identified. It is precisely the ocular manifestations that have the greatest impact on the patient's life: all these manifestations seriously compromise vision and the progressive thinning of the corneal stroma predisposes to corneal ruptures even from minor trauma. Indeed when the cornea becomes particularly thin it is unable to withstand normal biomechanical stresses and spontaneous rupture can occur.

It concerns three siblings (two 28 year old twin boys and a 25 year old woman) who presented a previous history of rupture of eyeball in one eye and very poor vision in the other. At the first ophthalmoscopic and instrumental evaluation,  three patients presented with bluish sclera and keratoglobus in the intact eye. A genetic analysis with whole exome sequencing was then performed on the three siblings, identifying a biallelic variant of the PRDM5 gene that led to the diagnosis.

Given the poor best corrected visual acuity achievable with glasses and contact lenses, penetrating keratoplasty was performed. The donor cornea was set with 10.0 nylon radial interrupted sutures;  sutures were deeply taken in the donor tissue while long suture bites were set in the recipient cornea in order to optimize the sealing: -a secure graft-host interface was created, focal stress on the marginal tissue avoided and  “cheese-wiring” of the sutures reduced. The following knots rotation  was made with extreme caution  to avoid  intraoperative corneal rupture in such fragile tissue. 

The immediate post-operative period was free of complications. The patient was instructed to use protective polycarbonate glasses,  and forced to adopt lifestyle changes to reduce any ocular trauma. The post-surgical follow-up included six-monthly checks with evaluation of BCVA, corneal topography (figure 1E) anterior segment OCT Visante (figure 1F) and pachymetry. The last two-year follow up confirms a stability of the topographic and pachymetric findings and the maintenance of a BCVA of 20/30  in two of the three patients.

Brittle Cornea Syndrome is a rare, and difficult to manage, disease. Its infrequency, together with having systemic manifestations similar to other pathologies often lead to underdiagnosis of this disease with disastrous consequences. It is therefore necessary to know the existence of this pathology in order to be able to carry out the right diagnostic investigations, and, once the diagnosis has been made, implement the right complication prevention and management procedures.