A corneal transplant, or keratoplasty, is a surgical procedure designed to restore vision by replacing a damaged or diseased cornea with healthy donor tissue. Following this surgery, a post-operative regimen is necessary to ensure the long-term success of the graft. The cornerstone of this care involves the use of steroid eye drops, and patients must strictly adhere to the prescribed schedule.
The Primary Role of Steroid Drops
The main function of the steroid drops is to act as an immunosuppressant directly at the site of the corneal graft. When donor tissue is placed into the recipient eye, the body’s immune system recognizes it as foreign material. This triggers an inflammatory and immune response that can lead to graft rejection.
The topical corticosteroids, such as prednisolone acetate or dexamethasone, work by dampening this reaction. They reduce the migration of inflammatory cells and minimize swelling. By suppressing the immune system’s activity in the eye, the drops create a more tolerant environment for the new corneal tissue. This allows the graft to remain clear and functional, preventing the most common cause of long-term failure, which is immunologic rejection.
Standard Duration and Tapering Schedule
The duration for which steroid drops are used is individualized and can range from many months to, in some cases, indefinitely. While the initial, high-frequency dosing is typically reduced over the first six to twelve months, many patients are kept on a low, maintenance dose for years, especially following a full-thickness transplant (Penetrating Keratoplasty, or PK). The exact length of time is determined by the type of transplant performed and the stability of the patient’s eye.
The process of gradually reducing the medication is known as “tapering.” For example, a patient may start with drops four times daily, then reduce to three times daily, then once daily, and eventually to an every-other-day schedule. Abruptly stopping the steroid drops is strongly discouraged, as this sudden loss of immunosuppression is a major trigger for an acute rejection episode, which can severely compromise the graft’s clarity.
The surgeon customizes this tapering schedule based on the patient’s risk factors and the specific transplant technique used, such as Descemet Stripping Endothelial Keratoplasty (DSEK) or PK. For a low-risk procedure like DSEK, the potent steroids might be switched to a lower-potency option like fluorometholone or loteprednol after three to six months to mitigate side effects. A long-term, low-dose regimen is common to maximize graft survival, as rejection can occur years after the initial surgery.
Monitoring Potential Side Effects
While topical steroids are necessary for preventing rejection, their prolonged use carries the risk of specific ocular side effects that require continuous monitoring. The two most significant complications are the development of steroid-induced glaucoma and the acceleration of cataract formation.
Steroid-induced glaucoma is caused by the elevation of the intraocular pressure (IOP) within the eye. The risk of developing this complication increases with the potency of the steroid and the duration of its use. This condition can lead to permanent vision loss if the high pressure damages the optic nerve.
For this reason, regular follow-up appointments with the ophthalmologist are essential, even when the patient is on a low maintenance dose. These visits include checking the intraocular pressure to catch any elevation early, allowing the doctor to adjust the steroid regimen or add pressure-lowering drops. Long-term steroid use is also associated with the formation of a posterior subcapsular cataract, which is a clouding at the back of the eye’s lens.