Intravitreal dexamethasone 0.7mg implants for the treatment of Retinitis Pigmentosa-associated cystoid macular edema

Abstract

Purpose : Retinitis pigmentosa (RP) is an inherited retinal degenerative disorder that leads to photoreceptor cell loss associated with apoptosis, oxidative cell damage, and neuroinflammation. Cystoid macular edema (CME) has been demonstrated to be a negative prognostic factor. Our purpose is to report long-term outcomes in a retrospective consecutive case series of patients with RP-associated CME, refractory to systemic acetazolamide who received intravitreous dexamethasone implant 0.7mg (IVDI) therapy.

Methods : Patients underwent IVDI treatment according to a treat and extend protocol. After IVDI, patients were monitored for CME recurrence via spectral domain optical coherence tomography (SDOCT) and retreated with IVDI as needed. Outcome measures included best-corrected visual acuity (BCVA) and SDOCT macular thickness. Patients were monitored for cataract and ocular hypertension. One sample t-test was used to determine statistical significance between groups when samples were normally distributed; otherwise, one sample signed rank test was used.

Results : Four patients (8 eyes) underwent IVDI. Baseline macular volume was 7.74±1.19 mm³ (range 6.45-9.54mm³), BCVA was logMAR 0.357±0.271 (range logMAR 0.05-0.8), and intraocular pressure (IOP) measured 14.5±5.93 mmHg (range 8-27). All eyes had recurrent macular edema and fluctuations in BCVA requiring IVDI retreatment. Eyes were treated with an average of 11.6 ±4.60 implants (range 6-18) over a span of 40.8.0±3.52 months (range 38.0-46.0). Average time between implants was 100.3±35.5 days. Six of 8 eyes demonstrated significantly improved visual acuity (p<0.01).Mean BCVA at date of last follow-up was logMAR 0.78±0.92 (range logMAR 0.1-3.0). Three of 8 patients demonstrated significantly improved macular volume (p<0.001). Mean macular volume at date of last follow-up was 7.69±0.98 mm³ (range 6.47-9.29mm³). Four of 8 eyes required between 1-3 IOP lowering medications. Clinically significant elevation of IOP occurred in 5 of 8 eyes (mean post-tx IOP:15.38±7.85 mmHg [range 5-28]). One patient required selective laser trabeculoplasty bilaterally. Seven of 8 eyes underwent cataract surgery during the study.

Conclusions : Repeat IVDI improves VA in a majority of eyes with RP and CME. A majority of eyes experienced increased IOP and required cataract extraction. In conclusion, IVDI deserves consideration for refractory CME in patients with RP.

This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.