ABSTRACT
Macular edema (ME) in retinitis pigmentosa (RP) often impairs central vision dramatically. A 41-year-old woman diagnosed with RP was referred to our outpatient clinic due to severe visual deterioration in both eyes. The patient was treated with topical carbonic anhydrase inhibitors, topical corticosteroids and intravitreal triamcinolone acetonide injections, but her ME recurred. Intravitreal 0.7 mg dexamethasone implant (Ozurdex, Allergan) was administered into both eyes without complications. On the fourth day after both injections, visual acuity improved and ME almost totally resolved. No recurrence was observed at follow-up six months later.
Introduction
Macular edema (ME) in retinitis pigmentosa (RP) often impairs central vision dramatically. ME has been shown in at least one eye in 32% of patients and in both eyes in 18% of patients in a recent optical coherence tomography (OCT) study.1Although the pathogenesis of RP-related ME has not been fully established, general inflammatory response to degenerating photoreceptors and retina pigment epithelium, defective blood-aqueous barrier, and autoimmune process (antiretinal antibodies) have been proposed as the possible causes.2,3,4
Treatment options include carbonic anhydrase inhibitors, corticosteroids, anti-vascular endothelial growth factor (anti-VEGF) agents, grid laser photocoagulation and vitrectomy.5,6,7,8,9Off-label intravitreal injection of triamcinolone has also been found to be effective.4A sustained-release dexamethasone implant is available for the treatment of ME secondary to retinal vein occlusion and in recent years it has been shown to have favorable results in the treatment of ME secondary to RP.5,6
Here, we report a case with bilateral refractory ME secondary to RP which dramatically improved within the first week following dexamethasone implant.
Discussion
There are several recent reports of intravitreal injection of dexamethasone implant (Ozurdex) for the treatment of ME secondary to RP.10,11,12,13Srour et al.10administered intravitreal dexamethasone implant in 3 patients with mean central macular thickness (CMT) of 443±185 µm (range 213-619 µm) and mean visual acuity of 20/160 (20/50-20/200) at baseline. One month after dexamethasone implantation, mean CMT improved to 234±68 µm and mean BCVA improved to 20/100. Saatci et al.11reported a case with bilateral ME secondary to RP. Visual acuity of the patient was 2/10 in both eyes and he had been under topical dorzolamide treatment 3 times a day for nearly a year without any change in VA. One week after the injection his visual acuity improved to 4/10 and ME resolved. Buchaim et al.12also reported successfully using intravitreal dexamethasone implant for the treatment of ME due to RP. Very recently, Ahn et al.13treated a 24-year-old patient with RP who developed CME in both eyes that was refractory to oral acetazolamide and intravitreal bevacizumab treatment. Despite a second intravitreal dexamethasone implant injection, CME recurred in both eyes 6 months later. The intravitreal dexamethasone implant may be useful for CME in patients with RP, but its efficacy seems to be limited over time. In our case, visual acuity improvement was almost the same with intravitreal triamcinolone acetonide injection and intravitreal dexamethasone implant. No recurrence was observed up to six months following the dexamethasone implant injection. ME and visual loss were more severe (CMT, 1071 µm) in the left eye due to damage to the external limiting membrane and photoreceptor layers. Despite severe structural changes in the macular area, ME resolved almost totally and visual acuity improved from CF to 20/800 at the 4th day visit, which made the patient very satisfied.
Conclusion
Although the follow-up period of our patient was short, long-lasting refractory ME secondary to RP may respond very rapidly to intravitreal dexamethasone implant with satisfactory results both for the patient and ophthalmologist. Further studies with larger sample size and longer durations are needed to clarify this issue.
