Mr J, age 70, presented with a rapid deterioration in vision in the right eye over one week. Mr J has a past history of keratoconus, with a full thickness corneal transplant in the right eye performed thirty years ago. Mr J wears contact lenses in both eyes and normally sees well in both eyes.
The loss of vision in the right eye was not associated with any other symptoms, in particular there was no pain, redness or light sensitivity. There had been no previous issues with the corneal transplant.
The examination revealed visual acuities of 6/120 in the right eye and 6/9 in the left eye. The cornea transplant in the right eye revealed severe corneal oedema affecting 80% of the transplant, with a small area of the transplant superiorly still being clear. The eye was not inflamed, there was no keratic precipitates and no anterior chamber activity.
Corneal topography revealed a thickened cornea and was otherwise not helpful.
What are the common causes of corneal transplant oedema?
- Acute Corneal Transplant Rejection which can occur for a number of reasons, including infection, sutures loosening or breaking, not using steroid drops when required or in some cases for no obvious reason.
- Corneal Transplant Endothelial Failure – simply deterioration of the transplant over time with loss of endothelial cells.
What is the likely cause in this case?
The likely cause in this case is spontaneous detachment of Descemets’ Membrane. This rare but recognised problem can occur at any stage after corneal transplant surgery, and can be easily confused for corneal transplant failure. Often Descemets’ Membrane can be difficult to visualise due to overlying corneal oedema. Anterior segment OCT can be very useful in assisting with the diagnosis of this problem. The detached Descemets’ Membrane can be clearly visualized on the OCT image above.
Spontaneous Descemets’ Detachment can be treated by injection of gas, either air or longer acting gas such as SF6 into the anterior chamber, and then having the patient posture to allow the air to reposition the membrane. If this treatment is unsuccessful, repeat corneal transplantation, either endothelial or full thickness can be performed.
In this case, air injected into the anterior chamber successfully cleared the corneal transplant.
Descemets’ Membrane is now attached. Mr J returned to wearing his contact lens in the right eye, with a visual acuity of 6/9. Certainly a quicker recovery than a repeat corneal transplant!