Children who undergo penetrating keratoplasty (PK) for herpes simplex virus (HSV) keratitis require long-term antiviral prophylaxis. This, according to the largest case series yet to evaluate the outcome of pediatric corneal transplantation.
PK in children is a challenge, with a high failure/rejection rate and a difficult postoperative course. Previous studies show that half of children experience HSV recurrence 13 to 15 months after the initial episode. Though this case series included just 9 patients, it shows that if recurrence, hypertension and amblyopia are aggressively managed, these children can achieve good visual outcomes.
Of the 9 patients (aged 3 to 17) with disciform or interstitial keratitis included in this paper, 4 were already inactive upon arrival to the center, 3 presented during the first active occurrence, and 2 presented with a secondary recurrence of disease. In all instances, the infection had resulted in a scar over the central visual axis. Patients were given oral acyclovir for at least 6 months prior to surgery to deactivate the infections and continued a prophylactic postoperative course for 6 to 33 months. The median follow-up time from initial visit was 94 months and 49 months from time of corneal transplant.
Previous research has shown that a positive prognosis following corneal transplantation for HSV may be hindered by many factors including recurrence, corneal vascularization, occurrences of rejection/inflammation, younger age at time of surgery, long delay between symptom onset and treatment, optical distortion in the graft – especially cases requiring refractive surgery – and most importantly, amblyopia.
In line with these findings, the authors found that of the 2 patients who did not experience improvement in postoperative BCVA, 1 had residual corneal opacity due to an episode of herpetic recurrence in the graft 8 months postop and showed poor adherence to amblyopia therapy, and the other had a 5-year delay from onset of symptoms to presentation at the center.
Most patients showed a significant improvement in BCVA at the final follow-up compared to baseline with a median of 20/50 (range 20/30 to 20/400) compared to 20/400 (range 20/60 to hand motion), respectively (P=0.001). Adverse events were limited, with 1 patient requiring a glaucoma drainage device after developing glaucoma at 1 year.
The only HSV recurrence occurred when the postop acyclovir course was interrupted, and quiescence was achieved following a continued regimen. Only 1 graft rejection event was observed, 15 years after implantation, and was successfully treated with systemic acyclovir and topical corticosteroids. No graft had failed by the end of the follow-up.
The study highlights the importance of long-term regimens of antiviral prophylaxis for reducing the risk of HSV recurrence, decreasing the episodes of rejection, and giving better overall graft survival.