Dexamethasone Intravitreal Implant in Vitrectomized Versus Nonvitrectomized Eyes for Treatment of Patients with Persistent Diabetic Macular Edema

Abstract

Purpose:

To compare the 6-month anatomic and best-corrected visual acuity (BCVA) response after sustained-release dexamethasone (DEX) intravitreal implant between nonvitrectomized and vitrectomized eyes with persistent diabetic macular edema (DME).

Methods:

Retrospective, comparative, and consecutive review of the medical records of 58 patients with decreased visual acuity, due to refractory DME, who underwent a single injection of Ozurdex between November 2010 and January 2012, at the Instituto de Microcirurgia Ocular, Barcelona, Spain. Then, we divided patients into 2 groups: 24 eyes who had undergone standard pars plana vitrectomy (vitrectomized group), and 34 eyes that were not operated on (nonvitrectomized group). Outcomes measured were BCVA and foveal thickness (FT) at baseline and at months 1, 3, and 6.

Results:

Twenty-four of 58 eyes had prior vitrectomy (41%). Statistically significant improvement in BCVA also was seen at 1 month after treatment with a DEX implant and at each subsequent follow-up visit, in either groups (P<0.05). All of the FT reduction outcomes were statistically significant in both groups, with respect to baseline data (P<0.05). There were no statistically significant differences in BCVA and FT between nonvitrectomized and vitrectomized eyes at any time point (P<0.05).

Conclusion:

In this study, the clinical findings were similar between nonvitrectomized and vitrectomized eyes. Intravitreal treatment with a DEX implant safely reduced DME and improved visual acuity in both groups. No statistically significant differences were found between the 2 groups regarding FT and BCVA.

Introduction

Pars plana vitrectomy (PPV) is beneficial in many conditions, including diabetic retinopathy (DR), diabetic macular edema (DME), retinal detachment, macular holes, macular pucker, and vitreous hemorrhage. In DR, both the delivery of oxygen to the retina and the removal of inflammatory mediators of DME, such as vascular endothelial growth factor (VEGF), from the retina are improved after vitrectomy.¹ PPV effectively treats DME associated with vitreomacular traction, but several authors have also documented excellent results following surgery for fovea involving diffuse DME without apparent vitreomacular traction.^2–6 However, for many patients, the chronic and recurrent nature of retinal diseases requires continued drug therapy after surgical procedure.^7–9 Experience with VEGF¹⁰ and a number of drugs, including triamcinolone acetonide,^11,12 amphotericin B,¹³ and 5-fluorouracil,¹⁴ suggests that some drugs are cleared more rapidly in vitrectomized eyes. Indeed, further intravitreal pharmacologic treatment of posterior segment disease may be less effective after removal of the vitreous. Drug clearance from the vitreous cavity is more rapid in vitrectomized eyes, limiting drug exposure to the retina and reducing treatment success and options. Therefore, differences in pharmacokinetics between nonvitrectomized and vitrectomized eyes may influence the clinical effectiveness of drug therapy.

Glucocorticoids such as DEX exert their anti-inflammatory effects by influencing multiple signal transduction pathways, including VEGF.^15–18 By binding to cytoplasmic glucocorticoid receptors, corticosteroids in high doses increase the activation of anti-inflammatory genes, whereas at low concentrations they have a role in the suppression of activated inflammatory genes.^16,19

The DEX implant (Ozurdex; Allergan, Inc., Irvine, CA) is a novel approach approved by the United States Food and Drug Administration (FDA) and by European Union (EU) for the intravitreal treatment of macular edema after branch or central retinal vein occlusion and for the treatment of noninfectious uveitis affecting the posterior segment of the eye.²⁰ However, there is evidence for efficacy in multiple clinical situations, including DME, ME associated with uveitis or Irvine-Gass syndrome, DME in vitrectomized eyes, persistent ME, and noninfectious vitritis.^15–22

The objective of this study was to compare the ocular effectiveness profile of a single intravitreal injection of Ozurdex in nonvitrectomized and vitrectomized eyes of diabetic patients with DME. The patient population included severe cases that had not responded to multiple previous therapies.

Methods

Enrollment of study subjects

We retrospectively reviewed the medical records of 67 consecutive patients with decreased visual acuity, due to refractory DME, who underwent a single injection of Ozurdex between November 2010 and January 2012, at the Instituto de Microcirurgia Ocular, Barcelona, Spain. Of these patients, 58 patients were enrolled in the study. Then, we divided patients into 2 groups: 24 eyes who had undergone standard PPV (vitrectomized group), and 34 eyes that were not operated on (nonvitrectomized group).

Baseline characteristics of patients and study eyes, in either group, are listed in Tables 1 and 2. All patients had been previously exposed to a variety of treatments for DR and DME. Key inclusion criteria included previous treatment with anti-VEGF agents, other intraocular steroids or laser photocoagulation with only a partial response to the previous treatments (Tables 3 and 4). Refractory DME was defined as persistent ME with foveal thickness (FT) 250 μm by spectral domain optical coherence tomography (SD-OCT), lasting for at least 90 days after laser or intravitreal anti-VEGF/steroid treatment.

Table 1.

Baseline Demographics and Clinical Features in the Nonvitrectomized Group

Patient no.	Sex	Age (years)	BCVA Baseline	BCVA Month 1	BCVA Month 3	BCVA Month 6	Foveal thickness Baseline	Foveal thickness Month 1	Foveal thickness Month 3	Foveal thickness Month 6
1	M	70	0.50	0.50	0.70	0.50	695.00	545.00	419.00	476.00
2	M	59	0.40	0.40	0.40	0.40	523.00	444.00	434.00	507.00
3	M	66	0.80	0.30	0.40	0.40	762.00	181.00	233.00	321.00
4	M	66	0.80	0.40	0.40	0.70	696.00	193.00	243.00	352.00
5	M	66	0.70	0.40	0.50	0.50	688.00	457.00	677.00	643.00
6	M	66	0.70	0.40	0.30	0.50	616.00	407.00	587.00	612.00
7	F	78	0.40	0.30	0.20	0.40	746.00	432.00	457.00	717.00
8	M	82	1.30	1.00	0.70	1.00	525.00	536.00	211.00	411.00
9	F	59	0.30	0.20	0.18	0.30	273.00	267.00	267.00	222.00
10	F	66	0.70	0.70	0.50	1.00	535.00	387.00	328.00	361.00
11	M	63	1.00	0.80	0.80	1.00	889.00	654.00	566.00	866.00
12	M	56	0.70	0.50	0.40	0.40	480.00	329.00	279.00	299.00
13	F	84	0.70	0.50	0.50	0.40	333.00	238.00	232.00	283.00
14	F	62	0.10	0.10	0.10	0.18	462.00	411.00	323.00	352.00
15	F	77	2.00	1.60	1.30	1.30	925.00	778.00	643.00	699.00
16	F	77	1.00	1.00	0.80	0.80	523.00	367.00	322.00	411.00
17	M	68	0.70	0.70	0.50	0.50	346.00	166.00	156.00	178.00
18	M	81	0.50	0.30	0.30	0.40	625.00	248.00	242.00	502.00
19	M	46	1.00	0.70	0.70	0.70	510.00	184.00	259.00	567.00
20	M	78	0.40	0.30	0.30	0.30	541.00	258.00	312.00	536.00
21	M	78	0.80	0.80	0.80	1.30	603.00	451.00	430.00	631.00
22	M	61	0.20	0.40	0.40	0.50	526.00	351.00	317.00	318.00
23	M	75	0.50	0.20	0.20	0.20	599.00	403.00	496.00	529.00
24	F	62	0.20	0.18	0.18	0.18	354.00	306.00	273.00	401.00
25	M	71	0.70	0.70	0.70	0.70	692.00	478.00	397.00	481.00
26	M	65	0.20	0.20	0.18	0.20	497.00	321.00	322.00	402.00
27	M	68	1.30	0.50	0.70	0.70	416.00	460.00	514.00	529.00
28	M	32	0.50	0.40	0.30	0.30	411.00	221.00	237.00	310.00
29	F	24	0.20	0.10	0.10	0.10	369.00	257.00	306.00	317.00
30	F	60	0.50	0.40	0.30	0.40	524.00	397.00	370.00	411.00
31	F	63	0.80	0.70	0.50	0.70	460.00	332.00	290.00	321.00
32	M	66	0.20	0.18	0.18	0.18	438.00	426.00	431.00	496.00
33	F	36	0.70	0.20	0.18	0.50	611.00	236.00	588.00	596.00
34	M	59	0.50	0.40	0.20	0.20	303.00	224.00	238.00	230.00

BCVA, best-corrected visual acuity; F, female; M, male.

Table 2.

Baseline Demographics and Clinical Features in the Vitrectomized Group

Patient no.	Sex	Age (years)	BCVA Baseline	BCVA Month 1	BCVA Month 3	BCVA Month 6	Foveal thickness Baseline	Foveal thickness Month 1	Foveal thickness Month 3	Foveal thickness Month 6
1	M	60	0.70	0.50	0.40	0.20	512.00	332.00	261.00	303.00
2	F	66	0.70	0.70	0.50	0.50	686.00	218.00	459.00	450.00
3	M	59	0.40	0.40	0.40	0.40	283.00	273.00	273.00	287.00
4	M	68	0.30	0.30	0.20	0.18	422.00	337.00	276.00	274.00
5	M	64	0.20	0.20	0.20	0.20	501.00	419.00	272.00	354.00
6	M	40	1.00	0.80	0.70	0.70	638.00	367.00	173.00	456.00
7	M	64	0.40	0.20	0.20	0.50	643.00	265.00	634.00	756.00
8	M	57	0.18	0.10	0.10	0.10	334.00	268.00	206.00	249.00
9	M	46	0.70	0.70	0.70	1.00	567.00	292.00	173.00	229.00
10	M	62	0.50	0.40	0.40	0.50	581.00	338.00	316.00	428.00
11	M	64	1.00	1.00	0.50	0.40	276.00	231.00	288.00	311.00
12	F	65	1.10	1.00	0.40	0.40	658.00	336.00	402.00	477.00
13	F	65	1.30	1.30	1.30	1.30	764.00	219.00	207.00	301.00
14	M	72	0.50	0.18	0.20	0.20	560.00	264.00	254.00	309.00
15	M	72	0.40	0.20	0.20	0.18	607.00	443.00	245.00	336.00
16	M	66	0.50	0.30	0.20	0.18	826.00	314.00	306.00	325.00
17	F	62	0.70	0.50	0.30	0.30	507.00	233.00	211.00	239.00
18	F	65	1.00	0.50	0.50	0.50	437.00	347.00	320.00	372.00
19	M	65	0.70	0.40	0.20	0.20	597.00	323.00	322.00	344.00
20	F	65	1.00	1.00	0.40	1.00	552.00	315.00	307.00	387.00
21	M	58	0.50	0.30	0.20	0.40	543.00	387.00	334.00	585.00
22	F	61	1.30	1.00	1.00	0.80	835.00	672.00	602.00	698.00
23	M	70	0.70	0.70	0.70	0.80	264.00	234.00	234.00	256.00
24	M	62	0.70	0.80	0.70	0.70	419.00	344.00	311.00	356.00

Table 3.

History of Posterior Segment Procedures in the Study Eye, in the Nonvitrectomized Group

Posterior segment procedure	Number of patients (n=34) 100% Any previous treatment for DME n (%)
PPV	None
Focal laser	31 (91.2%)
Panretinal photocoagulation	26 (76.5%)
IV anti-VEGF	25 (73.5%)
IV triamcinolone	24 (70.6%)

PPV, pars plana vitrectomy; IV, intravitreal; DME, diabetic macular edema; Anti-VEGF, anti-vascular endothelial growth factor.

Table 4.

History of Posterior Segment Procedures in the Study Eye, in the Vitrectomized Group

Posterior segment procedure	Number of patients (n=24) 100% Any previous treatment for DME n (%)
PPV	24 (100%)
Focal laser	20 (83.3%)
Panretinal photocoagulation	17 (70.8%)
IV anti-VEGF	19 (79.2%)
IV triamcinolone	15 (62.5%)

Exclusion criteria were diagnosis of uncontrolled systemic disease, glaucoma, elevated intraocular pressure, epiretinal membrane or vitreomacular traction in the study eye that could prevent improvement in visual acuity as well as any intraocular injection, intraocular surgery, or laser treatment in the study eye within the previous 3 months.

Informed consent was obtained from all patients in agreement with the Declaration of Helsinki for research involving human subjects.

Examination

At baseline, all patients underwent a complete ophthalmic evaluation, including best corrected visual acuity (BCVA) using standardized ETDRS charts, tonometry, fluorescein angiography and SD-OCT (Cirrus HD-OCT; Carl Zeiss Meditec, Inc., Dublin, CA) with FT measurement.

Intravitreal sustained-release dexamethasone device

A dexamethasone intravitreal implant (DEX implant, 0.7 mg) consists of a biodegradable copolymer of polylactic-co-glycolic acid containing micronized DEX, which is slowly released. DEX implant resulted in sustained levels of DEX and biological activity for 6 months, with peak levels of drug over the first 2 months.^23–25 Compared with the published data describing other routes of administration of DEX analogues, several results demonstrate a few advantages of this implant.^20–29

Treatment

Patients received a DEX implant in the study eye at the baseline visit (Day 1). A single-use applicator with a 22-gauge needle was used to place a DEX implant in the vitreal chamber through a self-sealing scleral injection. All injections were performed in the operating room.

All of them returned to our institution at regular intervals after the surgical procedure for ocular and systemic follow-up. Patients were seen at outcome assessment study visits at day 2 and at months 1, 3, and 6.

All patients were monitored for any local or systemic adverse effects during the whole study.

The primary outcome measure was the change from baseline in BVCA and in FT from baseline to month 6, in both groups.

Statistical analysis

Statistical calculations were performed using the Statistical Package for Social Sciences (version 19.0; SPSS, Inc., Chicago, IL). Patients' ETDRS BCVA were transferred from their records and converted to a logarithm of the minimal angle of resolution (logMAR) scale for analysis.

Mean changes from baseline FT and BCVA were analyzed using paired t-tests, in both groups. Additionally, functional and anatomic final differences between nonvitrectomized and vitrectomized eyes were determined using the independent samples Student's t-test. A 2-tailed test with an alpha level of 0.05 was used for all comparisons.

Results

During the inclusion period of the study, refractory DME that had undergone DEX implant was identified in 67 patients. Of these patients, 58 patients were enrolled in the study.

Figure 1 depicts the mean logMAR BCVA for both groups at 4 different time points: baseline, 1, 3, and 6 months. Statistically significant improvements in the mean logMAR BCVA were seen in both groups within 30 days after the intravitreal DEX injection. These significant changes continued throughout the 6-month follow-up, regarding to baseline. In the non-operated group (n=34), the mean baseline logMAR BCVA was 0.65±0.38 logMAR. The mean BCVA improved to 0.48±0.31 logMAR (P=0.0001), 0.44±0.27 logMAR (P=0.0001) after 1, and 3 months, respectively. At the last visit (6-month follow-up), the mean BCVA increased to 0.52±0.31 logMAR (P=0.004).

FIG. 1.

Mean changes from baseline best-corrected visual acuity (BCVA) in both groups.

In the vitrectomized group (n=24), the mean baseline logMAR BCVA of 0.69±0.32 improved to 0.56±0.33 at 1 month (P=0.0001), 0.44±0.29 at 3 months (P=0.0001), and 0.48±0.32 at 6 months (P=0.001).

In both groups, there was further significant improvement in the mean logMAR BCVA between the 1- and 3-month follow-ups that was sustained up to 6 months (P=0.0001). However, the 3- and 6-month follow-ups did not differ statistically from the 1-month follow-up, in either group. No statistically significant differences in logMAR BCVA were found between the 2 dose groups (Table 3).

Statistically significant improvements in mean FT were seen in both groups within 1 month after the initial DEX implant injection (Fig. 2). These significant changes continued throughout the 6-month follow-up, but the 3- and 6-month follow-ups did not differ statistically from the 1-month follow-up in either group. Baseline mean FT was 544.00±157.09 μm (nonvitrectomized group) and 542.16±159.07 μm (ppv group). In the nonvitrectomized group, mean (SD) values of FT did decrease to 363.08±139.05 μm (P=0.0001) at month 1 and to 364.67±135.06 μm (P=0.0001) at month 3. Data on the 6-month follow-up showed a mild increase to 449.61±157.31 μm (P=0.0001). In the vitrectomized group the mean FT decreased to 323.79±96.22 μm (P=0.0001) at 1 month, 307.75±116.17 μm (p=0.0001) at 3 months and increased to 378.42±136.98 μm (P=0.0001) at 6 months. All of the FT reduction outcomes were statistically significant, with respect to baseline data. No statistically significant differences in FT were found between the 2 dose groups (Table 5).

FIG. 2.

Mean changes from baseline foveal thickness in both groups.

Table 5.

Dexamethasone Intravitreal Implant in Vitrectomized Versus Nonvitrectomized Eyes for Treatment of Patients with Persistent Diabetic Macular Edema

	BCVA mean			FT mean
	NON VIT	VIT	P-value	NON VIT	VIT	P-value
Baseline	0.65±0.38	0.69±0.32	0.681	544.00±157.09 μm	542.16±159.07 μm	0.965
1 month	0.48±0.31	0.56±0.33	0.367	363.08±139.05 μm	323.79±96.22 μm	0.237
3 months	0.44±0.27	0.44±0.29	0.863	364.67±135.06 μm	307.75±116.17 μm	0.100
6 months	0.52±0.31	0.48±0.32	0.637	449.61±157.31 μm	378.42±136.98 μm	0.079

NON VIT, nonvitrectomized group; VIT, vitrectomized group; FT, foveal thickness.

No serious ocular and systemic adverse events were observed.

Discussion

In this study, we have reported similar vitreoretinal DEX effectiveness after administration of the 0.7-mg DEX implant in nonvitrectomized and vitrectomized eyes. Both mean FT and mean BCVA had improved from baseline by 1 month after treatment with a DEX implant, and the improvement remained statistically significant throughout the 6-month study, in both groups.

The functional peak effectiveness of DEX implants was seen at 3 months after injection in either group, when mean FT improved to 307.75±116.17 μm from baseline in the vitrectomized group and to 364.67±135.06 (m in the nonoperated on group. There were no statistically significant differences in BCVA and FT between nonvitrectomized and vitrectomized eyes at any time point (P<0.05). The improvement in FT seen in the operated eyes was more pronounced in relation to the improvement seen in the remaining nonvitrectomized patients with persistent macular edema, albeit not statistically significant.

Over the past 3 decades, we have addressed the DME issue by using focal and grid pattern laser photocoagulation as well as intravitreal injections of corticosteroids and most recently, intravitreal injections of anti-VEGF drugs. PPV has been shown to be useful in the treatment of DME in some patients.^{2–6,30–34} The mechanism for the effect of vitrectomy on DME may involve both release of vitreomacular traction and increased diffusion of advanced glycation end products, VEGF, and other cytokines away from the retina.^1,31–33 These findings suggest that sustained drug delivery with an implant could be particularly useful in vitrectomized eyes, thus enhancing and boosting the primary effect of vitrectomy.

The DRCR.net trial prospectively enrolled 241 eyes with treatment-resistant DME.³⁵ At 6 months after vitrectomy, the mean FT decreased from 412 to 278 μm. Eyes with greater preoperative thickness, an epiretinal membrane, and vitreomacular traction achieved greater thinning. Although the average VA (20/80) of the entire cohort did not change, BCVA improvement was seen in eyes with worse baseline vision (P<0.001) and in those requiring the removal of ERMs (P=0.006). These authors concluded that vitrectomy may have a role in eyes with vitreomacular abnormalities, but they could not recommend vitrectomy for eyes without traction. This study reported valuable information but, unfortunately, no information regarding the utility of early, primary vitrectomy for DME.

In accordance, a systematic review and meta-analysis of published, randomized, controlled trial data was conducted by Simunovic et al. to systematically review and evaluate the available data regarding the efficacy of vitrectomy for DME.³⁶ Seven studies compared vitrectomy with the natural history of diabetic maculopathy, with laser, or with intravitreal corticosteroid injection. Four studies compared vitrectomy with internal limiting membrane peeling to vitrectomy alone. One of the latter 4 studies was the only to investigate vitrectomy in patients with vitreomacular traction. Meta-analysis suggests a structural and possibly functional superiority of vitrectomy over observation at 6 months. Vitrectomy also appears superior to laser in terms of structural, but not functional, outcomes at 6 months. At 12 months, vitrectomy offers no structural benefit and a trend toward inferior functional outcomes when compared with laser.

Actually, there is little clinical evidence to support vitrectomy as an intervention for DME in the absence of epiretinal membrane or vitreomacular traction.

Intravitreal delivery of corticosteroids^27,37–43 and anti-VEGF antibodies^44–48 are addressing many of the problems associated with conventional therapies for the treatment of retinal diseases. Studies in rabbits have shown that the vitreous half-life of triamcinolone acetonide (TA) after intravitreal injection is reduced in eyes after PPV compared with nonvitrectomized eyes.^11,12 Vitrectomy has also been shown to affect the intraocular concentration of TA after intravitreal injection in human eyes.^49,50 In a vitrectomized eye, the vitreous would be removed, and less-viscous liquid would fill the space, increasing intravitreal circulation. This pathophysiological process leads to a much faster corticosteroid absorption in the vitrectomized eye than in the normal eye. An implant that provides sustained drug release and is both safe and effective may be the best option for therapy.

Moreover, an earlier study⁴⁰ examining the in vivo release of DEX sodium m-sulfobenzoate from a biodegradable poly (lactic acid) (PLA) implant suggests that the pharmacokinetics of DEX may be different in nonvitrectomized and vitrectomized eyes. In this earlier study conducted in rabbit eyes, the release of DEX from the PLA implant (which has chemical similarities with the DEX implant) was 2.5 times more rapid in vitrectomized eyes than in nonvitrectomized eyes. In contrast, the release of DEX from the DEX implant in a more recent study was similar between nonvitrectomized and vitrectomized eyes in rabbit eyes.²⁵ These results suggest that DEX implants may be particularly useful in the treatment of inflammation and macular edema in vitrectomized eyes. Our data are consistent with those obtained from this later experimental study carried out by Chang-Lin et al.

In our study, a near complete subtotal vitrectomy was performed in all patients. Given that the completeness of vitrectomy may influence the rate of clearance of many drugs,^10–12 the extent of vitrectomy should be considered when comparing findings between nonvitrectomized and vitrectomized eyes.

Regarding the efficacy of a DEX intravitreal drug-delivery system in persistent ME secondary to diabetes, Haller et al.²¹ demonstrated that, in eyes with DME treated with DEX implant, BCVA and FT significantly improved at 3 months when compared with the observation group. Interestingly, they found that BCVA improvement was no longer significant at 6 months. Unfortunately, this randomized trial did not investigate the corresponding change in FT at the same time point.

Most recently, 4 interventional case series studies addressed this issue. In the first study, Zucchiatti et al.²⁹ showed that a single intravitreal injection of Ozurdex produced improvement in BCVA and FT in eyes with persistent DME. Such improvement was evident from the third day to the first month after injection, peaked at the third month and was no more significant at 6 months. Analogously, Rishi et al.⁵¹ undertook another retrospective study, enrolling 18 patients with refractory DME. All patients experienced a significant reduction in FT compared with baseline levels at month 1. The maximum reduction in FT was seen at month 1, followed by reappearance of clinically significant ME at month 4. In 2013, Pacella et al. performed a prospective interventional case series to assess the efficacy of DEX implant, over a 6-month follow-up period.⁵² Ozurdex produced substantial improvement in BCVA and significant reduction of FT from day 3. The peak efficacy of the implant appears to be reached at month 1 through to month 3, then slowly decreases from month 4 to 6.

Similarly, we performed a retrospective interventional case series study to evaluate the effectiveness of a single intravitreal injection of Ozurdex, over 6 months in patients with persistent DME.⁵³ Both mean FT and mean BCVA improved from baseline by 1 month after treatment and remained statistically significant throughout the 6-month study. The peak effectiveness of DEX implants was seen at 3 months after injection when mean FT had decreased by 37%.

In the past decades, corticosteroids have raised interest in the treatment of DME due to their anti-inflammatory effects, and because they inhibit the synthesis of VEGF and reduce vascular permeability. However, this clinical application has been mitigated and the use of corticosteroids has been drastically reduced in most developed countries, in the last few years, due to safety concerns.⁵⁴

Recently, the safety profile of Ozurdex, which is currently an approved treatment for retinal vein occlusion, has been reported in the GENEVA study.²⁰ DEX intravitreal implants have demonstrated an acceptable safety profile in several studies.^20,55 The implant does not need to be removed because the copolymer slowly biodegrades into carbon dioxide and water and is absorbed over time.

To our knowledge, there have been no differences on the relative effectiveness of DEX implants in pseudophakic versus phakic eyes. Further studies will be needed to ascertain whether the effects of DEX implants are affected by lens status.

Our study has several limitations–in that it is short-term, open-label, retrospective, and evaluates a small study population–that preclude any estimation of the long-term efficacy or safety of intravitreal Ozurdex. Another limitation was that information about the status of the underlying diabetes in the study population was not recorded.

So far, no study, comparing the difference in BCVA and FT (qualitative and quantitative measures, respectively), between vitrectomized and nonvitrectomized eyes has been reported targeting the DME issue.

This study has demonstrated similar effectiveness of DEX in nonvitrectomized and vitrectomized eyes after the administration of a 0.7-mg DEX implant. According to our results, the recent DEX implant Ozurdex 0.7 mg will probably be a useful addition to our local armamentarium in the treatment of persistent DME given its efficacy, safety, and ease of use in the outpatient setting and support the conducting of clinical trials in this patient population, even in the operated on patients.

Footnotes

Author Disclosure Statement

All the listed authors agree with the submission of this article and none of them have any conflicting financial interests related to it, current and over the past 5 years.

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