Clinical applications of the sustained-release dexamethasone implant for treatment of macular edema

Intravitreal dexamethasone: variation of surgical technique and prevention of ocular complications with ASOCT follow-up

PURPOSE

To verify the correct decision-making procedure on performing an intravitreal injection by investigating the in vivo wound morphology and evolution of 22-gauge wounds after dexamethasone oblique injection with anterior segment optical coherence tomography (OCT).

DESIGN

Prospective, observational consecutive case series.

METHODS

Subjects underwent a dexamethasone injection at University Eye Clinic of Turin. All the injections have been performed in an oblique (aka beveled or angled) fashion. Patients were divided according to the number of injections already performed with dexamethasone. Group 1 consisted of patients at the first injection, group 2 of patients at a second or more injection always in the same quadrant, and group 3 of patients at the second or more injection in a different quadrant. The incisions were imaged with the Heidelberg SPECTRALIS OCT device on postoperative days 1, 8, and 15. The main outcome measure was wound structure/characteristics (e.g., presence of gaping) as evaluated with OCT. Surgical and ocular parameters were also recorded.

RESULTS

Thirty-three consecutive patients were investigated. OCT demonstrated closed wounds in all eyes on postoperative days 1, 8, and 15. In all patients, the external (entry) side of the incision was seen as a gape; however, the rest of the wound was closed. No complications were recorded in the different patients during the follow-up. In patients of group 1, we identified the scleral pathway in 10 eyes at day 1. At 8 days in 9 of 10 eyes, the sclera had returned to its restitutio ad integrum. In patients of group 2, the scleral pathway was recognizable on the first day of control; in 7 patients, this was accompanied by the presence of intrascleral edema with peri-wound fluid. At the 8-day checkup, 3 eyes still showed signs attributable to the intrascleral pathway accompanied by peri-wound edema. In group 3, it was possible to identify the intrascleral pathway in 8 patients. There were no signs of intrascleral peri-wound edema or other anatomical changes in 9 patients as early as the first day. In the 8-day follow-up, the signs of scleral edema were absent in the single patient who presented them. At 15 days, there were no signs of scleral pathway in all eyes analyzed.

CONCLUSIONS

Speaking of intravitreal injections of slow-release dexamethasone, the technique that involves moving the conjunctiva and a beveled or angled sclerotomy after a careful choice of the injection site, paying attention to vary the quadrant involved with each puncture, reduces the number of days of closure of the sclera via and the scleral damage, thus protecting the patient from complications. For the future, it is hoped that the operating microscope and intraoperative OCT will be used on every occasion.

Polymer-free corticosteroid dimer implants for controlled and sustained drug delivery

Polymeric drug carriers are widely used for providing temporal and/or spatial control of drug delivery, with corticosteroids being one class of drugs that have benefitted from their use for the treatment of inflammatory-mediated conditions. However, these polymer-based systems often have limited drug-loading capacity, suboptimal release kinetics, and/or promote adverse inflammatory responses. This manuscript investigates and describes a strategy for achieving controlled delivery of corticosteroids, based on a discovery that low molecular weight corticosteroid dimers can be processed into drug delivery implant materials using a broad range of established fabrication methods, without the use of polymers or excipients. These implants undergo surface erosion, achieving tightly controlled and reproducible drug release kinetics in vitro. As an example, when used as ocular implants in rats, a dexamethasone dimer implant is shown to effectively inhibit inflammation induced by lipopolysaccharide. In a rabbit model, dexamethasone dimer intravitreal implants demonstrate predictable pharmacokinetics and significantly extend drug release duration and efficacy (>6 months) compared to a leading commercial polymeric dexamethasone-releasing implant.

Dexamethasone PLGA Microspheres for Sub-Tenon Administration: Influence of Sterilization and Tolerance Studies

Many diseases affecting the posterior segment of the eye require repeated intravitreal injections with corticosteroids in chronic treatments. The periocular administration is a less invasive route attracting considerable attention for long-term therapies. In the present work, dexamethasone-loaded poly(lactic-co-glycolic) acid (PLGA) microspheres (Dx-MS) were prepared using the oil-in-water (O/W) emulsion solvent evaporation technique. MS were characterized in terms of mean particle size and particle size distribution, external morphology, polymer integrity, drug content, and in vitro release profiles. MS were sterilized by gamma irradiation (25 kGy), and dexamethasone release profiles from sterilized and non-sterilized microspheres were compared by means of the similarity factor (f₂). The mechanism of drug release before and after irradiation exposure of Dx-MS was identified using appropriate mathematical models. Dexamethasone release was sustained in vitro for 9 weeks. The evaluation of the in vivo tolerance was carried out in rabbit eyes, which received a sub-Tenon injection of 5 mg of sterilized Dx-MS (20–53 µm size containing 165.6 ± 3.6 µg Dx/mg MS) equivalent to 828 µg of Dx. No detectable increase in intraocular pressure was reported, and clinical and histological analysis of the ocular tissues showed no adverse events up to 6 weeks after the administration. According to the data presented in this work, the sub-Tenon administration of Dx-MS could be a promising alternative to successive intravitreal injections for the treatment of chronic diseases of the back of the eye.

Complications of dexamethasone implants: risk factors, prevention, and clinical management

AIM

To evaluate major complications after intravitreal injection of dexamethasone implants (Ozurdex) and their clinical management.

METHODS

In a retrospective observational study between 2014 and 2016 at two university hospitals, we reviewed the clinical records of 1241 consecutive macular edema patients treated with the dexamethasone implant, and separated severe adverse events in the injection procedure from those that were post-injection complications. We evaluated the cause and the outcomes in each case.

RESULTS

In twenty-one procedures (1.69%) we noticed significant complications during and after intravitreal injection of the dexamethasone implant. Complications related to the injection procedure were in one case, that a second implant was injected by mistake in the same eye on the same day. In another case, the implant lodged in the sclera during retraction of the injector needle. Leaking scleral tunnel at the injection site led to hypotony in another case. There were 10 cases of post-injection displacement of the implant into the anterior chamber and one case with a migrated and trapped device between the intraocular lens and an artificial iris. Displacement typically occurred in patients with preexisting risk factors: eyes with complicated intraocular lens implantation, iris reconstruction or iris defects or pseudophakic eyes after vitrectomy were prone to develop this complication. Displacement led to secondary corneal decompensation with pseudohypopyon. One case developed an endophthalmitis, and we observed four cases of retinal detachment. Two eyes presented with long-lasting hypotony due to ciliary insufficiency.

CONCLUSION

Treatment with the dexamethasone implant may cause various expected or unexpected complications that may have serious consequences for the patient and require further surgery. To reduce complications, clinicians should evaluate certain risk factors before scheduling patients for dexamethasone implant treatment and use proper injection techniques.

Chitosan Derivatives with Mucoadhesive and Antimicrobial Properties for Simultaneous Nanoencapsulation and Extended Ocular Release Formulations of Dexamethasone and Chloramphenicol Drugs

The aim of this work was to evaluate the effectiveness of neat chitosan (CS) and its derivatives with 2-acrylamido-2-methyl-1-propanesulfonic acid (AAMPS) and [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide (MEDSP) as appropriate nanocarriers for the simultaneous ocular administration of dexamethasone sodium phosphate (DxP) and chloramphenicol (CHL). The derivatives CS-AAMPS and CS-MEDSP have been synthesized by free-radical polymerization and their structure has been proved by Fourier-Transformed Infrared Spectroscopy (FT-IR) spectroscopy. Both derivatives exhibited low cytotoxicity, enhanced mucoadhesive properties and antimicrobial activity against Staphylococcus aureus (S.aureus) and Escherichia coli (E. coli). Encapsulation was performed via ionic crosslinking gelation using sodium tripolyphosphate (TPP) as the crosslinking agent. Dynamic light scattering measurements (DLS) showed that the prepared nanoparticles had bimodal distribution and sizes ranging from 50–200 nm and 300–800 nm. Drugs were encapsulated in their crystalline (CHL) or amorphous (DexSP) form inside nanoparticles and their release rate was dependent on the used polymer. The CHL dissolution rate was substantially enhanced compared to the neat drug and the release time was extended up to 7 days. The release rate of DexSP was much faster than that of CHL and was prolonged up to 3 days. Drug release modeling unveiled that diffusion is the main release mechanism for both drugs. Both prepared derivatives and their drug-loaded nanoparticles could be used for extended and simultaneous ocular release formulations of DexSP and CHL drugs.

Manufacturing of Dexamethasone-Poly(d,l-Lactide-co-Glycolide) Implants Using Hot-Melt Extrusion: Within- and Between-Batch Product Performance Comparisons

Purpose: Reliable drug therapy with injectable intravitreal implants requires implants of consistent quality. The purpose of this study was to prepare dexamethasone-poly(d,l-lactide-co-glycolide) (PLGA) biodegradable implants and assess implant quality within and between batches for different polymer compositions. Methods: Implants containing 20% w/w dexamethasone with 3 theoretical rates of release (fast, intermediate, and slow) were manufactured with decreasing proportion of acid-terminated PLGA (50:50) and increasing proportion of ester-terminated PLGA (50:50) in a batch process using hot-melt extrusion. The implants were manufactured without and with in-process modification of extrusion/conveyor speed in the late phase of each batch. Implant samples collected at early, middle, and late phases of each batch were analyzed for diameter, drug loading, mechanical properties (strength and toughness), and drug release. Results: With a fixed process, unlike a modified process with an increase in extrusion speed and reduction of conveyor speed in the late phase, all implant formulations tended to decrease in diameter and mechanical properties in the late phase. Drug release profiles for the intermediate and slow release compositions were similar with or without process modification, unlike the fast release composition. Addition of ester-terminated PLGA resulted in a slower drug release. When all formulations are grouped together, the implant diameter exhibited a moderate correlation with mechanical properties, but no correlation was observed with drug release. Conclusions: Within a hot-melt extrusion batch process, the dexamethasone-PLGA implant diameter and hence toughness and strength tend to decline in the latter phase. In-process adjustment of extrusion and conveyor speeds can improve batch consistency and, potentially, implant integrity or performance during or after injection. Process changes did not affect drug release for 2 of the 3 implant compositions.

Dexamethasone Loaded Liposomes by Thin-Film Hydration and Microfluidic Procedures: Formulation Challenges

Liposomes have been one of the most exploited drug delivery systems in recent decades. However, their large-scale production with low batch-to-batch differences is a challenge for industry, which ultimately delays the clinical translation of new products. We have investigated the effects of formulation parameters on the colloidal and biopharmaceutical properties of liposomes generated with a thin-film hydration approach and microfluidic procedure. Dexamethasone hemisuccinate was remotely loaded into liposomes using a calcium acetate gradient. The liposomes produced by microfluidic techniques showed a unilamellar structure, while the liposomes produced by thin-film hydration were multilamellar. Under the same remote loading conditions, a higher loading capacity and efficiency were observed for the liposomes obtained by microfluidics, with low batch-to-batch differences. Both formulations released the drug for almost one month with the liposomes prepared by microfluidics showing a slightly higher drug release in the first two days. This behavior was ascribed to the different structure of the two liposome formulations. In vitro studies showed that both formulations are non-toxic, associate to human Adult Retinal Pigment Epithelial cell line-19 (ARPE-19) cells, and efficiently reduce inflammation, with the liposomes obtained by the microfluidic technique slightly outperforming. The results demonstrated that the microfluidic technique offers advantages to generate liposomal formulations for drug-controlled release with an enhanced biopharmaceutical profile and with scalability.

Effect of intravitreal dexamethasone implant on the contralateral eye in recalcitrant radiation maculopathy

Radiation maculopathy, a subset of significant radiation retinopathy, is one of the most common causes of visual loss following localized, regional, or whole-brain radiotherapy. Ozurdex (Allergan Inc., Irvine, CA, USA), a sustained-release intravitreal implant of 0.7 mg dexamethasone, has been used as an off-label treatment for treating recalcitrant radiation maculopathy. However, to the best of our knowledge, the beneficial effect of intravitreal dexamethasone in the contralateral eye in a patient with radiation maculopathy has not been described in the literature so far. In this case report, we report the efficacy of dexamethasone 0.7 mg intravitreal implant in recalcitrant radiation maculopathy which was refractory to intravitreal bevacizumab therapy. The patient showed good anatomical and functional outcomes in both the eyes after unilateral injection of intravitreal dexamethasone as evident by optical coherence tomography scans and fundus fluorescein angiography. It is noteworthy that the contralateral was not treated for 4 years. The case reveals systemic exposure of dexamethasone after intravitreal injection by demonstrating the bilateral effect after unilateral injection of intravitreal dexamethasone

A more efficient ocular delivery system of triamcinolone acetonide as eye drop to the posterior segment of the eye

As a leading cause of vision impairment of the retina, macular edema (ME) has one of the highest clinical demands for treatment. Current treatment of ME relies heavily on invasive techniques resulting in complications and poor patient compliance. To enhance the efficiency of triamcinolone acetonide as eye drop to the posterior segment of the eye, we developed and characterized a novel formulation, namely, triamcinolone acetonide chitosan-coated liposomes (TA-CHL), prepared by the calcium acetate gradient method with some modifications. TA-CHL provided the mean particle size of 135.46 ± 4.49 nm and high entrapment efficiency (90.66 ± 3.21%), exhibited a sustained release profile, excellent physical stability, and no significant toxicity on cornea, conjunctiva, and retina. Optical coherence tomography system (OCT) was used to detect pharmacokinetics of CHL in vivo, indicating that CHL had good potency for drug delivery. Cellular uptake experiments showed CHL had the higher transduction efficiency into HCEC and ARPE-19 than liposomes. TA-CHL was shown to be potentially effective eye drop to contribute to the posterior segment of the eye.

Periocular Triamcinolone vs. Intravitreal Triamcinolone vs. Intravitreal Dexamethasone Implant for the Treatment of Uveitic Macular Edema: The PeriOcular vs. INTravitreal corticosteroids for uveitic macular edema (POINT) Trial

PURPOSE

To evaluate the comparative effectiveness of 3 regional corticosteroid injections for uveitic macular edema (ME): periocular triamcinolone acetonide (PTA), intravitreal triamcinolone acetonide (ITA), and the intravitreal dexamethasone implant (IDI).

DESIGN

Multicenter, randomized clinical trial.

PARTICIPANTS

Patients with uveitic ME.

METHODS

Patients were randomized 1:1:1 to receive 1 of the 3 therapies. Patients with bilateral ME were assigned the same treatment for both eyes.

MAIN OUTCOME MEASURES

The primary outcome was the proportion of baseline (PropBL) central subfield thickness (CST) at 8 weeks (CST at 8 weeks/CST at baseline) assessed with OCT by masked readers. Secondary outcomes included ≥20% improvement and resolution of ME, best-corrected visual acuity (BCVA), and intraocular pressure (IOP) events over 24 weeks.

RESULTS

All treatment groups demonstrated improved CST during follow-up. At 8 weeks, each group had clinically meaningful reductions in CST relative to baseline (PropBL: 0.77, 0.61, and 0.54, respectively, which translates to reductions of 23%, 39%, and 46% for PTA, ITA, and IDI, respectively). Intravitreal triamcinolone acetonide (PropBL ITA/PropBL PTA, hazard ratio [HR], 0.79; 99.87% confidence interval [CI], 0.65-0.96) and IDI (PropBL IDI/PropBL PTA, HR, 0.69; 99.87% CI, 0.56-0.86) had larger reductions in CST than PTA (P < 0.0001). Intravitreal dexamethasone implant was noninferior to ITA at 8 weeks (PropBL IDI/PropBL ITA, HR, 0.88; 99.87% CI, 0.71-1.08). Both ITA and IDI treatments also were superior to PTA treatment in improving and resolving uveitic ME. All treatment groups demonstrated BCVA improvement throughout follow-up. Both ITA and IDI groups had improvements in BCVA that was 5 letters greater than in the PTA group at 8 weeks (P < 0.004). The risk of having IOP ≥24 mmHg was higher in the intravitreal treatment groups compared with the periocular group (HR, 1.83; 95% CI, 0.91-3.65 and HR, 2.52; 95% CI, 1.29-4.91 for ITA and IDI, respectively); however, there was no significant difference between the 2 intravitreal treatment groups.

CONCLUSIONS

Intravitreal triamcinolone acetonide and the IDI were superior to PTA for treating uveitic ME with modest increases in the risk of IOP elevation. This risk did not differ significantly between intravitreal treatments.

Quantitative evaluation of hard exudates in diabetic macular edema after short-term intravitreal triamcinolone, dexamethasone implant or bevacizumab injections

Background

To quantitatively compare short-term hard exudates (HEs) alteration in patients with diabetic macular edema (DME) after intravitreal triamcinolone, dexamethasone implant or bevacizumab injections.

Methods

This retrospective study enrolled DME eyes with HEs that underwent a single-dose intravitreal injection of triamcinolone (25 eyes), dexamethasone implant (20 eyes), or three monthly injections of bevacizumab (25 eyes) and completed at least three months of follow-up. All patients were examined before and after 1, 2 and 3 months of injections. Using color fundus photographs, the amount of HEs was quantified by two masked graders. The difference in HEs area between baseline and each follow-up visit was compared among the three groups.

Results

After three months, HEs area was reduced to 52.9 ± 4.21% (P < 0.001) in the triamcinolone group, 63.6 ± 6.08% (P = 0.002) in the dexamethasone implant group, and 85.2 ± 5.07% (P = 0.198) in the bevacizumab group. A significant reduction in HEs appeared at one month in the triamcinolone group (53.5 ± 4.91%, P < 0.001) and at two months in the dexamethasone implant group (70.1 ± 5.21%, P = 0.039).

Conclusions

Our study suggests intravitreal steroids (triamcinolone, dexamethasone implants) significantly reduce HEs in DME patients on short-term follow-up, whereas intravitreal bevacizumab does not. Therefore, intravitreal steroids may be useful in DME with HEs in the fovea.

Self-powered therapeutic release from conducting polymer/graphene oxide films on magnesium

Magnesium's complete in vivo degradation is appealing for medical implant applications. Rapid corrosion and hydrogen bubble generation along with inflammatory host tissue response have limited its clinical use. Here we electropolymerized a poly (3,4-ethylenedioxythiophene) (PEDOT) and graphene oxide (GO) film directly on Mg surface. GO acted as nano-drug carrier to carry anti-inflammatory drug dexamethasone (Dex). PEDOT/GO/Dex coatings improved Mg corrosion resistance and decreased the rate of hydrogen production. Dex could be released driven by the electrical current generated from Mg corrosion. The anti-inflammatory activity of the released Dex was confirmed in microglia cultures. This PEDOT/GO/Dex film displayed the ability to both control Mg corrosion and act as an on demand release coating that delivers Dex at the corrosion site to minimize detrimental effects of corrosion byproducts. Such multi-functional smart coating will improve the clinical use of Mg implants. Furthermore, the PEDOT/GO/Drug/Mg system may be developed into self-powered implantable drug delivery devices.

Efficacy and Safety of a Dexamethasone Implant in Patients with Diabetic Macular Edema at Tertiary Centers in Korea

Purpose. To evaluate the real-world efficacy and safety of the dexamethasone implant (DEX implant) in patients with diabetic macular edema (DME). Methods. Retrospective, multicenter, and noncomparative study of DME patients who were treated with at least one DEX implant. A total of 186 eyes from 165 patients were included. Best-corrected visual acuity (BCVA), central retinal thickness (CRT), complications, and number of retreatments were collected. Data at baseline and monthly for 6 months were analyzed. Results. The average baseline BCVA and CRT were 0.60 LogMAR and 491.6 μm, respectively. The mean BCVA improved until 3 months and then decreased up to 6 months of follow-up (0.53, 0.49, and 0.55 LogMAR at 1, 3, and 6 months; p = 0.001, <0.001, and 0.044, resp.). The change of mean CRT was similar to BCVA (345.0, 357.7, and 412.5 μm at 1, 3, and 6 months, p < 0.001, <0.001, and <0.001, resp.). 91 eyes (48.9%) received additional treatment with anti-VEGF or DEX implant. The average treatment-free interval was 4.4 months. In group analyses, the DEX implant was more effective in pseudophakic eyes, DME with subretinal fluid (SRF), or diffuse type. Conclusions. Intravitreal dexamethasone implants are an effective treatment for patients with DME, most notably in pseudophakic eyes, DME with SRF, or diffuse type. A half of these patients require additional treatment within 6 months.

Comparison of the release profile and pharmacokinetics of intact and fragmented dexamethasone intravitreal implants in rabbit eyes

PURPOSE

Dexamethasone intravitreal implant (DEX implant, Ozurdex(®); Allergan, Inc.) is used to treat noninfectious posterior uveitis and macular edema associated with retinal vein occlusion and diabetic retinopathy. Two recently published reports of DEX implant fragmentation shortly after injection have raised concerns about the potential for faster implant dissolution and elevated ocular dexamethasone concentrations. This study compared the in vivo release profile and pharmacokinetic behavior of intact and fragmented DEX implants.

METHODS

DEX implant was surgically implanted as a single unit or fragmented into 3 pieces in the posterior segment of opposing eyes of 36 New Zealand white rabbits. The release of dexamethasone over time from 1-piece and 3-piece fragmented implants dissolved in solution in vitro was compared with that from the 1-piece and 3-piece fragmented implants placed in the rabbit eyes. In addition, dexamethasone concentrations in the vitreous and aqueous humors of each eye were measured at 3 h and days 1, 7, 14, 21, and 28. High-performance liquid chromatography and liquid chromatography-tandem mass spectrometry were used for assays.

RESULTS

Dexamethasone release from the 1-piece and 3-piece DEX implants in vivo was not different and was consistent with the in vitro release pattern. Moreover, the concentration profile of dexamethasone in the vitreous and aqueous humors was similar for the 1-piece and 3-piece DEX implants at each time point measured.

CONCLUSIONS

DEX implant fragmentation neither accelerated its dissolution nor increased the dexamethasone concentration delivered at a given time. Accordingly, DEX implant fragmentation is unlikely to have clinically significant effects in patients.

Natural Compounds from Saffron and Bear Bile Prevent Vision Loss and Retinal Degeneration

All retinal disorders, regardless of their aetiology, involve the activation of oxidative stress and apoptosis pathways. The administration of neuroprotective factors is crucial in all phases of the pathology, even when vision has been completely lost. The retina is one of the most susceptible tissues to reactive oxygen species damage. On the other hand, proper development and functioning of the retina requires a precise balance between the processes of proliferation, differentiation and programmed cell death. The life-or-death decision seems to be the result of a complex balance between pro- and anti-apoptotic signals. It has been recently shown the efficacy of natural products to slow retinal degenerative process through different pathways. In this review, we assess the neuroprotective effect of two compounds used in the ancient pharmacopoeia. On one hand, it has been demonstrated that administration of the saffron constituent safranal to P23H rats, an animal model of retinitis pigmentosa, preserves photoreceptor morphology and number, the capillary network and the visual response. On the other hand, it has been shown that systemic administration of tauroursodeoxycholic acid (TUDCA), the major component of bear bile, to P23H rats preserves cone and rod structure and function, together with their contact with postsynaptic neurons. The neuroprotective effects of safranal and TUDCA make these compounds potentially useful for therapeutic applications in retinal degenerative diseases.

Dexamethasone Intravitreal Implant as Adjunctive Therapy to Ranibizumab in Neovascular Age-Related Macular Degeneration: A Multicenter Randomized Controlled Trial

Purpose: To evaluate the efficacy and safety of dexamethasone intravitreal implant 0.7 mg (DEX) as adjunctive therapy to ranibizumab in neovascular age-related macular degeneration (nvAMD). Procedures: This was a 6-month, single-masked, multicenter study. Patients were randomized to DEX implant (n = 123) or sham procedure (n = 120) and received 2 protocol-mandated intravitreal ranibizumab injections. The main outcome measure was injection-free interval to first as-needed ranibizumab injection. Results: DEX increased the injection-free interval versus sham (50th percentile, 34 vs. 29 days; 75th percentile, 85 vs. 56 days; p = 0.016). 8.3% of DEX versus 2.5% of sham-treated patients did not require rescue ranibizumab (p = 0.048). Visual acuity and retinal thickness outcomes were similar in DEX and sham-treated patients. Only reports of conjunctival hemorrhage (18.2 vs. 8.5%) and intraocular pressure elevation (13.2 vs. 4.2%) were significantly different in the DEX versus the sham treatment groups. Conclusion: DEX reduced the need for adjunctive ranibizumab treatment and showed acceptable tolerability in nvAMD patients.

Long-term evaluation of dexamethasone intravitreal implant in vitrectomized and non-vitrectomized eyes with macular edema secondary to non-infectious uveitis

PURPOSE

To compare dexamethasone (DEX) intravitreal implant effect in non-vitrectomized (non-PPV) vs vitrectomized (PPV) eyes with macular edema (ME) secondary to non-infectious uveitis.

METHODS

Medical records of patients with uveitic ME treated with DEX-intravitreal implant were reviewed. Main outcome measures were changes in central retinal thickness (CRT), best corrected visual acuity (BCVA), intraocular pressure (IOP), vitreous haze and adverse events. Statistical analysis was performed by Longitudinal Linear model using the General Estimating Equation methodology.

RESULTS

Forty-two eyes of 32 patients were included. Median follow-up time was 18 months (interquartile range (IQR): 12-24). Median CRT showed its maximum decrease at the first month in non-PPV and PPV eyes without statistically significant differences between both groups (P=NS). Median Snellen BCVA, converted to logarithm (LogMAR), showed its maximum improvement at third month in both groups without statistically significant differences between them (P=NS). Median IOP was higher in non-PPV eyes than in PPV eyes from third (P=0.025) to 12th month (P=0.013). Vitreous haze score improved in both groups since first month and showed no differences (P=0.706). Reinjection was performed in 45.2% of eyes at a median time of 5 months IQR: (5-6). Ocular hypertension (47.6%) was the most common adverse event.

CONCLUSIONS

DEX-intravitreal implant for uveitic ME has similar long-term safety profile and good response measured in terms of CRT decrease, BCVA, and vitreous haze improvement in both groups. Non-PPV eyes following DEX-intravitreal implant showed higher IOP increase than PPV eyes, showing the need for close IOP monitoring.

Advances in diabetic retinopathy

Diabetic retinopathy (DR) is a complication of long-term diabetes mellitus (DM). Over the last 2 decades lot of work has been on early diagnosis of DR and screening programs have been designed to help the masses. Large numbers of clinical studies have been done for patients of diabetes and DR wherein the role of blood sugar control, metabolic control, role of oral medicines for DR, role of imaging, fluorescein angiography, and retinal photocoagulation has been studied. Newer treatment modalities are being devised and studied for better patient care. We discuss these issues in our review highlight and newer advances over the last few years.

Efficacy of intravitreal dexamethasone implant for prostaglandin-induced refractory pseudophakic cystoid macular edema: case report and review of the literature

Background

Macular edema is a known complication even after uneventful cataract surgery. The chronic use of prostaglandin analogs is a risk factor for the development of pseudophakic cystoid macular edema (CME). Nonsteroidal anti-inflammatory drugs (NSAIDs) are considered first-line therapy but refractory postsurgical CME represents a therapeutic challenge, as there is not an evidence-based treatment.

Objective

To report the use of a single implant of intravitreal dexamethasone for tafluprost-associated pseudophakic CME refractory to NSAIDs and to sub-Tenon’s corticosteroid injections.

Case report

A 64-year-old female with ocular hypertension treated with tafluprost experienced decreased vision (visual acuity 20/60) and metamorphopsia 2 months after uneventful cataract extraction. Spectral domain optical coherence tomography (SD-OCT) revealed CME. After 1 month of topical and oral NSAIDs, CME was still evident on SD-OCT (visual acuity 20/50). Two sub-Tenon’s betamethasone injections were performed at a 2-week interval. As CME was still present, 2 months after the diagnosis of CME (visual acuity 20/40), the patient underwent a single dexamethasone intravitreal implant. One month later, macular appearance was normal, and visual acuity increased to 20/30. This result was maintained throughout the 6 months of follow-up.

Conclusion

In this report, a single implant of intravitreal dexamethasone successfully treated pseudophakic CME associated with the use of prostaglandin analogs unresponsive to NSAIDs and sub-Tenon’s betamethasone. The results of this report need to be corroborated by powered, prospective, randomized trials. The need for repeated treatments as well as the retreatment interval in patients requiring more than a single injection are issues still needing further investigations.

Steroid differentiation: the safety profile of various steroids on retinal cells in vitro and their implications for clinical use (an American Ophthalmological Society thesis)

PURPOSE

To determine if potentially viable alternatives to the clinical use of intravitreal triamcinolone acetonide should be considered based on a comparative assessment of the in vitro effects of five commercially available corticosteroids. We hypothesized that dexamethasone, betamethasone, methylprednisolone, loteprednol etabonate, and fluocinolone acetonide, at clinically relevant doses, may show different levels of in vitro cytotoxicity to retinal cells.

METHODS

Cultures of human retinal pigment epithelial cells (ARPE-19) and rat embryonal neurosensory precursor retinal cells (R28) were treated with dexamethasone, betamethasone, methylprednisolone, loteprednol, or fluocinolone acetonide. Cell viability as a measure of cell death was determined by trypan blue dye exclusion assay. The mechanical effect of drug crystals was evaluated by solubilizing the steroid formulations. Mitochondrial dehydrogenase and membrane potential were assessed to measure cell damage.

RESULTS

Betamethasone, loteprednol, and methylprednisolone, in commercially available forms, caused significant cytotoxic changes to retinal cells in vitro at clinically relevant doses. This effect was less pronounced with solubilized betamethasone. Dexamethasone at concentrations up to 5 times the clinical dose of free drug injections and 1000 times greater than a drug implant did not cause decreased cell viability. Fluocinolone acetonide at doses 1000 times higher than observed with drug delivery systems showed no cytotoxic effect.

CONCLUSIONS

Betamethasone, loteprednol, and methylprednisolone exhibited cytotoxicity at clinically relevant doses and do not appear to be good therapeutic options for intravitreal use. In comparison, dexamethasone and fluocinolone acetonide, which exhibited fewer cytotoxic effects than other steroids, may be potentially viable alternatives to triamcinolone acetonide for clinical use.

Evaluation of pain during intravitreal Ozurdex injections vs. intravitreal bevacizumab injections

PURPOSE

The purpose was to evaluate the pain associated with intravitreal Ozurdex injections, and to compare it with that associated with intravitreal bevacizumab injections.

METHODS

The study included 57 eyes of 57 patients who received an intravitreal Ozurdex injection at our institution. Pain was measured by the visual analog scale (VAS). Additional parameters recorded included age, sex, indication for the injection, number of previous Ozurdex injections in the study eye, presence of diabetes mellitus, and lens status. Data were compared with a 2 : 1 sex- and age-matched control group of 114 patients who received intravitreal bevacizumab injections.

RESULTS

Indications for injection included diabetic macular edema (40.4%) and macular edema secondary to central and branch retinal vein occlusion (28% and 31.6%, respectively). Pain scores on the VAS ranged from 0 to 90, with a mean of 20.8±20.3. There was no significant difference in pain between Ozurdex and bevacizumab injections. Pseudophakia was correlated with increased pain in Ozurdex injections.

CONCLUSIONS

This is the first series evaluating the pain associated with intravitreal Ozurdex injections. Despite a larger needle gauge and tunneled injection technique, intravitreal injection of Ozurdex is not associated with increased pain compared with bevacizumab. This finding may be a potential advantage for Ozurdex, and may serve to improve patient compliance with future long-term treatment protocols.

Five-month observation of persistent diabetic macular edema after intravitreal injection of Ozurdex implant

Aims. This retrospective analysis was aimed at evaluating the effectiveness of treatment of persistent diabetic macular edema with intravitreal injections of 0.7 mg dexamethasone implant Ozurdex. The study comprised three male patients (6 eyes). Results. The average thickness of the retina at baseline was 632 μm, the medial BCVA was 0.8 logMAR, and corrected intraocular pressure was 13.7 mmHg. The maximum decrease in mean retinal thickness was observed at four weeks following the treatment and was 365 μm (−267 μm) and visual acuity improved by an average of two lines and was 0.6 logMAR. The largest increase in mean retinal thickness to average of 528 μm (+164 μm) occurred at 16 weeks and the average BCVA was 0.614 lines BCVA logMAR. In one eye, there was a steroid cataract development after the third dose of dexamethasone implant of 0.7 mg. Conclusions. The intravitreal dexamethasone implant treatment of patients with persistent diabetic macular edema in whom laser photocoagulation proved to be ineffective and as a result they required a monthly injection of anti-VEGF factors (Ranibizumab, Bevacizumab) may be a good alternative to extending the interval of injections. However, reinjections involve a high risk of developing poststeroid cataracts, which is not without significance in middle-aged patients.

Objective area measurement technique for choroidal neovascularization from fluorescein angiography

The purpose of this study was to develop a non-biased method of quantitatively measuring choroidal neovascularization (CNV) areas based on late-phase fluorescein angiography (FA) images. Experimental CNV was induced in Long Evans rats by laser disruption of the Bruch's membrane. FA was performed weekly for 5weeks. Multi-Otsu thresholding (MOT) was used to quantify CNV in late-phase FA images from both experimental rodent CNV and wet age-related macular degeneration (wAMD) patients. Images were automatically thresholded into three levels based on the image histogram, with the highest level containing CNV. To determine the technique's ability to quantify CNV areas, rats were given either triamcinolone acetonide or dexamethasone sodium phosphate to treat CNV and compared to untreated rats. The rat CNV lesion areas measured from 5-week histology sections from each treatment group were compared to areas measured from the corresponding FA images. MOT was able to detect statistical decreases in rodent CNV area in the treatment groups versus control from weeks 3 through 5. The ratio of CNV area measured from histology to area measured from FA images was not statistically different between groups. Finally, to determine the usefulness of MOT on pathological morphologies of CNV, MOT was performed on late-phase FA images from patients with classic and diffuse CNV. The technique was able to segment classical CNV in wAMD patients, but performed poorly with diffuse CNV. MOT provides a robust, objective, and quantifiable area measurement of CNV lesion area in both experimentally-induced and pathological CNV. The results indicate that MOT could be a useful research tool in helping evaluate the effects of therapeutics on CNV growth.

Scleral fixation of dexamethasone intravitreal implant (OZURDEX®) in a case of angle-supported lens implantation

OZURDEX(®) is a biodegradable drug delivery system which has been reported to be an effective treatment in cases of macular edema. However, migration of the implant into the anterior chamber with elevation of intraocular pressure and corneal decompensation might occur in some cases. We report a case of an 80-year-old male who underwent intravitreal scleral fixation of OZURDEX(®) due to postoperative macular edema secondary to complicated cataract surgery. He had a previous angle-supported lens implantation with superior Nd:YAG laser iridotomy. During surgery, the dexamethasone implant was introduced into the vitreous cavity and sutured to the sclera using a 10-0 non-absorbable polypropylene suture to prevent the risk of anterior complications in case of migration into the anterior chamber. After 6 months of follow-up, the macular edema had disappeared completely, the drug delivery system was not observed in the posterior segment and best-corrected visual acuity improved from 20/125 to 20/40 (Snellen equivalent). Neither anterior nor posterior segment complications were reported during the follow-up period. Intravitreal scleral fixation of the OZURDEX(®) to the pars plana could be recommended as an alternative technique to avoid anterior migration of the device in a patient with an anterior chamber intraocular lens, which may lead to corneal decompensation and increased intraocular pressure.

Longstanding refractory pseudophakic cystoid macular edema resolved using intravitreal 0.7 mg dexamethasone implants

Background

Refractory pseudophakic cystoid macular edema (PCME) following cataract surgery has long posed a challenge to clinicians, but intravitreal injections with a sustained delivery 0.7 mg dexamethasone implant has emerged as a promising therapy for this condition.

Objective

To present a case of longstanding and refractory PCME with complete remission through 189 days of follow-up after two successive injections with intravitreal dexamethasone implants.

Case report

A 59-year-old male had experienced metamorphopsia for approximately 4 years and had been diagnosed with PCME 15 months earlier. Since the time of the diagnosis, the condition had been refractory to both subtenon triamcinolone acetonide and a total of five injections with intravitreal ranibizumab. After the last injection with ranibizumab, central subfield mean thickness was 640 μm, and the best corrected visual acuity was 78 Early Treatment Diabetic Retinopathy Study letters. Following an intravitreal injection with a dexamethasone implant, the macular edema resolved at the next follow-up. The macular edema returned 187 days after the first injection and was treated with another intravitreal dexamethasone implant. Again, the macular edema subsided completely, and best corrected visual acuity improved to 84 Early Treatment Diabetic Retinopathy Study letters, a condition which was maintained through an additional 189 days of follow-up.

Conclusion

Chronic PCME is traditionally a difficult condition to treat, but we are encouraged by the optimal response experienced with intravitreal sustained release dexamethasone implants in our patient whose longstanding PCME had been refractory to previous treatments with both subtenon triamcinolone and intravitreal ranibizumab. In this case, the condition appeared to be fully reversible once inflammation was controlled, but the need for monitoring and repeated injections remains an issue of concern.

Rhegmatogenous Retinal Detachment with a High Risk of Proliferative Vitreoretinopathy Treated with Episcleral Surgery and an Intravitreal Dexamethasone 0.7-mg Implant

Purpose

To report a case of rhegmatogenous retinal detachment with a high risk of proliferative vitreoretinopathy (PVR) effectively treated with episcleral surgery and an intravitreal dexamethasone 0.7-mg implant.

Methods

A 35-year-old Caucasian man with a macula-off rhegmatogenous subtotal retinal detachment that had persisted for 1 month in his myopic left eye presented several risk factors that could have led to the development of PVR after retinal detachment surgery. His best corrected visual acuity was hand motion. He received an intravitreal dexamethasone 0.7-mg implant (Ozurdex^®) after episcleral surgery to prevent this complication.

Results

At least 9 months after surgery, no sign of PVR or pucker has developed in the treated eye. Visual acuity improved to 0.2, the retina was attached and no complications were observed.

Conclusion

Intravitreal dexamethasone 0.7-mg implant (Ozurdex) could be considered as off-label treatment following episcleral surgery to prevent PVR.

Long-term evaluation of patients treated with dexamethasone intravitreal implant for macular edema due to retinal vein occlusion

PURPOSE

To evaluate the long-term visual prognosis and complications of patients who received intravitreal Ozurdex injections for the treatment of macular edema (ME) due to retinal vein occlusion (RVO).

METHODS

A total of 17 patients who received Ozurdex injections in our institution as part of the GENEVA study were recalled for examination. Recorded parameters included final visual acuity (VA), final retinal thickness by optical coherence tomography, persistence of ME, and the occurrence of any complications.

RESULTS

Mean follow-up time was 50.5 months. Patients with branch RVO (BRVO) had a more favorable prognosis than central RVO (CRVO), and their mean VA had improved significantly, whereas the mean VA for the patients with CRVO did not improve significantly. Retinal thickness had reduced significantly in the whole group and in each subgroup separately. Complications included 10 patients with cataract progression, 1 with elevated intraocular pressure, and 1 with neovascularization and vitreous hemorrhage.

CONCLUSIONS

This is the first reported long-term evaluation of patients treated with Ozurdex. Our results indicate that it has favorable long-term safety profile, and may have a beneficial effect on the visual prognosis in BRVO even in the absence of continuous treatment. Further research is required to establish the optimal retreatment schedule for Ozurdex.

The therapeutic potential of intraocular depot steroid systems: developments aimed at prolonging duration of efficacy

BACKGROUND

Corticosteroids play a major role in the treatment of many diseases of the posterior ocular segment. Systemically or topically administered steroids usually do not attain therapeutic concentrations in the retina, as they must first cross the blood-retina barrier. Intravitreal application is a useful alternative means of achieving therapeutic concentrations in the posterior segment but must be repeated every few weeks, because drugs given in this way have a short half-life. Intraocular sustained-release implants have been now developed in order to prolong the effect of intravitreal drugs and to lessen the need for repeated application. Macular edema is a typical indication for intravitreal steroid treatment.

METHODS

Selective review of the literature.

RESULTS

Various intravitreal corticosteroid implants have been evaluated in prospective, randomized clinical trials in recent years, and some have been approved for clinical use. Implants are either longer-acting and non-resorbable (fluocinolone acetonide implants) or shorter-acting and resorbable (dexamethasone implants). Major adverse effects of intravitreal corticosteroids include the induction or worsening of cataracts and elevated intraocular pressure. The likelihood of a complication varies from implant to implant and depends on the duration of action of the particular one used.

CONCLUSION

Intravitreal corticosteroid implants are a new option in the treatment of diseases of the posterior ocular segment. Long-term results are not yet available. The optimal treatment for these diseases will need to be the focus of further clinical research.

Radiation Macular Edema after Ru-106 Plaque Brachytherapy for Choroidal Melanoma Resolved by an Intravitreal Dexamethasone 0.7-mg Implant

Purpose

To report the effective treatment of radiation macular edema following ruthenium-106 plaque brachytherapy for a choroidal melanoma with a dexamethasone 0.7-mg (Ozurdex^®) intravitreal implant.

Methods

An interventional case report with optical coherence tomography (OCT) scans.

Results

A 65-year-old Caucasian woman was suffering from radiation macular edema following ruthenium-106 plaque brachytherapy for a choroidal melanoma on her left eye. She had undergone one intravitreal injection of 0.5 mg bevacizumab (Avastin^®, Genentech/Roche) in the following months without functional or anatomical improvement. Seven months after the development of radiation macular edema, she received a single intravitreal injection of dexamethasone 0.7 mg (Ozurdex). Four weeks following the injection, her best-corrected visual acuity improved from 0.3 to 0.5. Radiation macular edema resolved with a reduction of central retinal thickness from 498 μm before Ozurdex injection to 224 μm after Ozurdex injection, as measured by OCT scan.

Conclusion

Dexamethasone 0.7 mg (Ozurdex) has proven to be an effective treatment option in retinal vein occlusion and noninfectious uveitis. It can also be considered as off-label treatment in radiation macular edema following ruthenium-106 plaque brachytherapy for a choroidal melanoma.

Wandering Ozurdex(®) implant

Purpose

To report the behavior of intravitreal Ozurdex^® implant in eyes with post-lensectomy–vitrectomy (PLV) aphakia.

Methods

Retrospective chart review of three eyes with PLV aphakia (three patients with uveitis) who received intravitreal injection of Ozurdex^® for cystoid macular edema (one eye), persistent inflammation (one eye), and ocular hypotony (one eye). Final outcome was assessed in terms of effectiveness, stability, and tolerance of the implant.

Results

Following the implant, an initial improvement was seen in all the three eyes. However, the implant migrated into the anterior chamber (AC) at 1 week in two eyes and at 5 weeks in one eye, and wandered between the AC and vitreous cavity with changing postures of the patient. Two eyes developed corneal edema, of which one eye underwent implant removal from the AC.

Conclusion

Ozurdex^® implant should be contraindicated in eyes with PLV aphakia to avoid its deleterious effect on the corneal endothelium.

Cystoid Macular Edema after Complicated Cataract Surgery Resolved by an Intravitreal Dexamethasone 0.7-mg Implant

PURPOSE

To report the effective treatment of cystoid macular edema (CME) following complicated cataract surgery (resulting in Irvine-Gass syndrome) with a dexamethasone 0.7-mg (Ozurdex(®)) intravitreal implant.

METHODS

An interventional case report with optical coherence tomography (OCT) scans.

RESULTS

An 83-year-old Caucasian woman was suffering from CME following complicated cataract surgery on her left eye. She had undergone 3 intravitreal injections of dexamethasone 0.4 mg in the 3 months following the surgery without any improvement of visual function. Seven months after the cataract surgery, she received a single intravitreal injection of dexamethasone 0.7 mg (Ozurdex). Four weeks following the injection, her best-corrected visual acuity improved from 0.3 to 0.8. CME resolved with a reduction of central retinal thickness from 393 μm pre-Ozurdex injection to 212 μm post-Ozurdex injection, as measured by OCT scan.

CONCLUSION

Dexamethasone 0.7 mg (Ozurdex) has proven to be an effective treatment option in retinal vein occlusion and non-infectious uveitis. It can also be considered as off-label treatment in Irvine-Gass syndrome.