Intravitreal Dexamethasone Shows Promise for Treatment of Pseudophakic Macular Edema

Dr. Magna Vanessa Rodrigues

Credit: Ceoft

Nondiabetic and diabetic patients without retinopathy showed similar responses to an intravitreal dexamethasone implant as a treatment for refractory pseudophakic cystoid macular edema (PCME) following prior topical combined therapy.¹

Reports showed comparable vision improvements and reductions in mean thickness between the patient groups. Those with better anatomical and functional outcomes after initial topical treatment experienced greater benefits at 12 months after dexamethasone implantation.

“Our study indicates that nondiabetic and diabetic patients without retinopathy demonstrated similar results following intravitreal dexamethasone implant after combined topical therapy, suggesting that selected diabetic patients might have a comparable response to nondiabetic patients with PCME,” wrote the investigative team, led by Magna Vanessa Rodrigues, Federal University of Goias, Centro de Referencia em Oftalmologia.

A common complication following cataract surgery, PCE has an incidence of approximately 1% among patients with no known risk factors. Diabetes has been identified as a potential risk for an increased incidence of PCME after routine cataract surgery, but diabetes alone might not impair recovery and may not increase the relative risk when compared to non-diabetic control patients.²

Intravitreal dexamethasone implant is a novel therapeutic strategy for PCME, particularly for refractory patients who underwent conventional therapies. However, there is a paucity of data on its efficacy over an extended follow-up period. In this analysis, Rodrigues and colleagues evaluated the impact of intravitreal dexamethasone as a treatment for refractory PCME over 12 months.¹

Medical records of consecutive patients diagnosed with PCME after uneventful phacoemulsification with posterior chamber intraocular lens (IOL) implantation were assessed in 2 affiliated ophthalmic hospitals. A total of 58 eyes were initially identified between January 2016 and December 2018. Data from 42 pseudophakic subjects with uneventful cataract surgery and PCME diagnosed after ≥2 months follow-up of topical treatment were included in the analysis.

None of the participants used non-steroidal anti-inflammatory drugs (NSAIDs) or topical steroids before surgery. All subjects were treated with topical nepafenac 0.1% and topical prednisolone 1% 3 times daily in the postoperative period and for 2 months after diagnosis of PCME.

Ultimately, a total of 21 eyes of nondiabetic patients were compared to 21 eyes of patients with diabetes without diabetic retinopathy. The primary endpoint was the outcome of intravitreal dexamethasone implantation as a treatment for PCME, with the intent to evaluate the impact of diabetes on visual recovery and optical coherence tomography (OCT) improvements.

Baseline variables were similar between the patient groups, with an average diabetes duration of 11.8 years. The mean BCVA before topical treatment in nondiabetic and diabetic patients were 0.74 ± 0.32 logMAR and 1.15 ± 0.35 logMAR, respectively.

After initial topical treatment, nondiabetic and diabetic participants showed a mean gain of –0.11 ± 0.11 logMAR and –0.18 ± 0.11 logMAR, respectively, in mean BCVA (P = .09). At month 12, the mean gain in BCVA after intravitreal dexamethasone implantation was –0.35 ± 0.17 logMAR in nondiabetic participants and –0.55 ± 0.26 logMAR in diabetic patients, compared to initial treatment (P <.001).

Furthermore, after initial topical treatment, nondiabetic and diabetic patients experienced a mean reduction of –43.42 ± 53.66 µm and –58.76 ± 36.28 µm, respectively, Overall, there were no differences identified between the study groups (P = .56). At month 12, changes in CFT were –195.71 ± 93.23 µm (P <.001) for nondiabetic patients and –260.81 ± 198.69 µm for diabetic patients, compared to initial treatment (P <.001).

Linear regression analysis showed a gain in BCVA over the 12 months (r2 = .25, rho = –.48; P <.01), with a similar gain in nondiabetic patients (r2 = .17, rho = –.49; P <.01). However, in diabetic patients, the analysis showed a strong negative correlation (r2 = .46, rho = – .71; P <.01).

In their conclusion, Rodrigues and colleagues observed a permanent increase in BCVA gain up to month 6 after intravitreal dexamethasone implantation, noting the increase was maintained until the study ended at 12 months.

“A correlation was found between higher visual acuity gains following topical treatment and better improvement at month 12, demonstrating that patients with PCME who responded better to topical treatment had higher BCVA improvement after DEX implantation at month 12,” investigators wrote.

References

1. Rodrigues, M.V., Garcia, J.M.B., Pacheco, K.D. et al. Pseudophakic macular edema in nondiabetic and diabetic patients without diabetic retinopathy treated with intravitreal dexamethasone implant. Int J Retin Vitr 9, 56 (2023). https://doi.org/10.1186/s40942-023-00489-2
2. Fleissig E, Cohen S, Iglicki M, et al. Changes in choroidal thickness in clinically significant pseudophakic cystoid macular edema. Retina. 2018;38:1629–35.