RELEASE AND VELOCITY OF MICRONIZED DEXAMETHASONE IMPLANTS WITH AN INTRAVITREAL DRUG DELIVERY SYSTEM: Kinematic Analysis With a High-Speed Camera

AN EASY WAY TO PREVENT VELOCITY-RELATED COMPLICATIONS DURING DEXAMETHASONE IMPLANT INJECTION IN VITRECTOMIZED EYES

PURPOSE

To assess the impact of inserting an ophthalmic viscoelastic device into the dexamethasone (DEX) implant needle on pellet velocity in simulated vitrectomized eyes.

METHODS

Dexamethasone implants were injected into a calibrated ex vivo test chamber filled with balanced salt solution. All DEX implants were administered by the same physician, aiming for the same button depression time. In Group 1, three DEX implant injections were performed without an ophthalmic viscoelastic device, while in Group 2, the ophthalmic viscoelastic device was safely inserted into the DEX implant needle using a 27-gauge cannula just before the injection. The slow-motion video mode of the IPhone 14 was used to record the procedures and calculate time and distance measurements.

RESULTS

Group 1 exhibited a mean velocity of 450 mm/second for the DEX pellet in balanced salt solution, compared with 54.57 mm/second in Group 2. Furthermore, DEX pellets in Group 1 had horizontal displacements of 24, 29, and 31 mm, while those in Group 2 had displacements of 17, 16, and 15 mm.

CONCLUSION

Injecting an ophthalmic viscoelastic device into the DEX implant needle significantly decreases the velocity of the free pellet in balanced salt solution by 87.87%. This modification may help prevent potential velocity-related complications linked to DEX implantation in vitrectomized eyes.

Anterior Segment Optical Coherence Tomography Evaluation of a Dexamethasone Intravitreal Implant in the Crystalline Lens: A Case Report

Purpose

Ozurdex® is a dexamethasone intravitreal implant approved for the treatment of macular edema secondary to branch or central retinal vein occlusion, non-infectious uveitis affecting the posterior segment of the eye, and diabetic macular edema.

Patients and Methods

We report a case of an accidental injection of the implant into the crystalline lens, successfully managed by surgery afterwards. The case description is supported by Anterior Segment Optical Coherence Tomography (AS-OCT) images.

Results

A 69-year-old male was observed for bilateral diabetic macular edema. He had previously been treated with bevacizumab and aflibercept, with an incomplete anatomical response (<20% reduction in central macular thickness). The patient consented to undergo a bilateral intravitreal dexamethasone injection (dexamethasone intravitreal implant (0.7 mg)). The procedures were uneventful, except for an extensive conjunctival hemorrhage in the right eye. An appointment was scheduled for fifteen days later, however the patient missed it. Four months later, he referred OD vision loss, which occurred a few days after the injection, and the implant was found within the right crystalline lens. An AS-OCT was done to better understand the implant's location and entry point. Due to decreased visual acuity, the patient was scheduled for surgery. A phacoemulsification surgery with a three-piece hydrophobic intraocular lens implantation in the sulcus associated with anterior vitrectomy was done.

Conclusion

The injection of a dexamethasone implant is becoming increasingly common. Nonetheless, it must always be carried out carefully, to avoid complications. If the implant is accidentally injected into the crystalline lens, the AS-OCT can help determine its exact location, which is important for preparing the surgical plan and determining the appropriate timing.

Influence of prior treatment protocol on intravitreal dexamethasone implant behavior in patients with diabetic macular edema in real-world practice

BACKGROUND AND OBJECTIVE

Intravitreal dexamethasone implant (DEXI) has been placed as an effective option to treat diabetic macular edema (DME). However, there is no consensus on the best time to introduce it. We conducted a study to evaluate anatomical and functional behavior after the first DEXI according to previous treatment.

RESEARCH DESIGN AND METHODS

This retrospective, real-world study between 2013 and 2020 investigated changes in best-corrected visual acuity (BCVA) and central macular thickness (CMT at months 2 and 6 after the first DEXI in DME. Patients were divided into naive, early switch (≤3 anti-VEGF injections), or late switch (>3 anti-VEGF injections) groups.

RESULTS

Among 112 consecutive eyes, mean BCVA and CMT improved significantly in all groups at month 2, with no difference between them. However, this improvement was not maintained at 6 months. The Naíve group presented better BCVA all over the study period. The previously treated groups, which started with worse initial visual acuity, showed more visual gain without reaching the BCVA of the naive group. CMT performance was similar between groups.

CONCLUSIONS

There was similar anatomical and functional behavior in all groups. Poorer visual acuity at baseline was associated with worse functional outcome despite good anatomic response.

Safety and Effectiveness of Intravitreal Dexamethasone Implant (Ozurdex®) for the Treatment of Refractory Cystoid Macular Oedema (CMO) in Galway University Hospital

Aim:

The aim of this study is to assess the real-life effectiveness and safety of intravitreal Ozurdex in an Irish setting.

Background:

Ozurdex is an intravitreal dexamethasone implant that is used for the treatment of macular oedema secondary to retinal vein occlusion and diabetic macular oedema.

Methods:

This was a retrospective observational study of adult patients in University Hospital Galway who received an intravitreal dexamethasone implant (Ozurdex) for the treatment of cystoid macular oedema secondary to diabetic eye disease or retinal vein occlusion. The main outcome was the mean change in best-corrected visual acuity 3-6 months after the treatment.

Results and Discussion:

36 patients were included in the study. Overall, there was a 1.66 mean letter gain (SD 11.8) 3-6 months post-treatment. The proportion of patients who gained >10 letters was 15.6%. The mean reduction in CST was 110.6um (SD 255.7), and in the linear regression analysis, no variables were found to be significantly associated with a change in visual acuity. In terms of adverse events, 14.3% of patients had significant cataract progression and 20.6% of patients had a significant rise in IOP following intravitreal Ozurdex implant.

Conclusion:

Intravitreal Ozurdex was found to be safe and effective, supporting it as an appropriate second-line treatment in patients with refractory macular oedema secondary to diabetic eye disease and retinal vein occlusion. Further studies should be carried out to evaluate the possible predictors of visual acuity outcome.

Vitrectomy in full thickness macular holes on top of a pigment epithelial detachment in age-related macular degeneration (AMD). Surgical consideration and review of the literature

PURPOSE

To present the surgical treatment of a full thickness macular hole (MH) caused by a vitreomacular traction (VMT) on top of an adjacent subfoveal pigment epithelial detachment (PED) in age-related macular degeneration (AMD).

OBSERVATION

A 77-year-old female with a subfoveal PED receiving consecutive intravitreal injections noticed a sudden decreased visual acuity (VA) due to the development an occult MH in her right eye after 19 repeated intravitreal anti vascular endothelial growth factor (VEGF)-injections. Her initial VA declined from 20/50 to 20/400. The firm VMT induced a rupture of the multi-layered retina and may progress to an RPE-tear or possible to a subretinal haemorrhage. We discussed with the patient the risks of the natural progression and explained possible treatment options: We continued her anti-VEGF combined with air bubble injections to induce a posterior vitreous detachment, to stabilise the retinal architecture, reduce the subretinal fluid and avoid possible intraoperative bleeding. As injections did release the VMT, vitrectomy released the posterior vitreous from the optic nerve and trimmed it towards the central retina. Peeling with brilliant blue removed the internal limiting membrane without any signs of bleeding, rupture of the PED or enlargement of the MH, prior to the installation of 10% SF6 gas. The postoperative optical coherence tomography (OCT) on day 5 confirmed a closed MH, while the size, shape and pattern of the PED remained unchanged. Her VA increased from 20/400 to 20/50 (equal to her previous VA prior to the MH-formation). To avoid a potential progression of the PED, we maintained her retreatment intervals at 5 weeks for the next 6 months. A literature review presents similar intraoperative approaches and postoperative outcomes in 8 out of the 9 published cases.

CONCLUSIONS AND IMPORTANCE

VMT can induce an occult MH on top of a PED, causing a significant loss of vision. When gas injections are not successful, surgery may release the traction, restore the retinal architecture, and significantly improve and maintain the VA over a documented long-term observation. The epiretinal procedure should be assisted under regular anti-VEGF injections to maintain the subretinal architecture.

Surgical removal of inadvertent intralenticular sustained-release dexamethasone implant (ozurdex) and implant one-piece posterior capsule intraocular lens

To report the therapeutic efficacy and results of an accidentally injected intralenticular sustained-release dexamethasone implant (Ozurdex) in a patient with macular edema secondary to diabetic macular edema. Dexamethasone intravitreal implant is an approved formulation in the management of macular edema. The most common adversarial effects are an elevation of intraocular pressure (IOP) and cataract, but the unintentional injection of the dexamethasone implant into the lens is a particularly rare event.We report a case of a 72-year-old man treated for resistant Diabetic macular edema (DME) with dexamethasone intravitreal implant (Ozurdex, Allergan, Inc., Irvine, CA, USA) in which the technique was complicated by accidental implantation into the lens body and review the management. The patient underwent phacoemulsification of the lens, removal of the Ozurdex, intravitreal Avastin injection, and implant of a one-piece lens in the posterior capsule.

Retina Injury After Dexamethasone Injection Into a Vitrectomized Eye

Purpose:

This work reports a case of retinal and vitreous hemorrhage after a dexamethasone (Ozurdex, Allergan) intravitreal implant injection to treat clinically significant macular edema (ME) in a patient with moderate nonproliferative diabetic retinopathy.

Methods:

A 61-year-old woman who had a vitrectomy 3 years prior in the right eye underwent intravitreal dexamethasone implant injection in the right eye. Immediately after the injection, the patient noted numerous floaters, with visual acuity decline from 20/30 before injection, to counting fingers at 3 feet after injection. Dilated examination revealed the dexamethasone implant resting against the retina, just inferior to the inferior arcade. On 360° fundus examination, the retina was found to be flat and attached. Optical coherence tomography of the macula demonstrated that the dexamethasone implant was preretinal, possibly having lifted the internal limiting membrane.

Results:

Thirty minutes after the injection, the patient reported that her vision was starting to clear. The patient was informed about what had transpired and warned about signs and symptoms of retinal detachment. She canceled her 1-week follow-up appointment because her vision returned to baseline. By 4 weeks post injection, her vision was 20/20 without macular edema.

Conclusions:

This case represents the first reported instance in which retinal impact by an Ozurdex implant was observed without treatment and vision recovered to baseline.

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.

Incidence and treatment outcomes of secondary epiretinal membrane following intravitreal injection for diabetic macular edema

The purpose of this study was to investigate the incidence of secondary epiretinal membrane (ERM) after intravitreal injection and the effect of ERM on visual acuity and central macular thickness (CMT) in patients with diabetic macular edema (DME). We included 147 eyes of 95 patients over 18 years old who were diagnosed with DME from 2012 to 2016, treated with intravitreal injection, and followed-up more than 24 months. Mean CMT in the ERM group was significantly thicker than in the non-ERM group after 9, 12, 18, and 24 months. Secondary ERM developed in 9.5% of patients during follow-up. Compared to other agents, the incidence of secondary ERM was significantly higher after intravitreal injection of dexamethasone implant. Among patients in the ERM group, the mean decrease of CMT between pre-injection and 2 weeks post-injection was significantly less after secondary ERM formation than before ERM formation. Secondary ERM formation was significantly associated with the number of intravitreal injections and the use of dexamethasone implant. Therefore, secondary ERM develops more frequently as the number of intravitreal injections increases and after intravitreal dexamethasone implant injection. The therapeutic effects of intravitreal injections for DME patients decrease after secondary ERM formation.

Extramacular Retinal Hole Following Intravitreal Dexamethasone Implant: Case Report

The intravitreal dexamethasone implant Ozurdex is indicated for the treatment of macular edema due to diabetes and branch retinal vein occlusion. While the most common ocular side effects are elevated intraocular pressure and cataract formation, rare complications related to the injection have been reported. We present a case with extramacular retinal hole after Ozurdex injection.

Accidental Intralenticular Injection of Ozurdex® for Branch Retinal Vein Occlusion: Intact Posterior Capsule and Resolution of Macular Edema

Purpose

We present a case of accidental intralenticular injection of Ozurdex implant in a patient with macular edema secondary to branch retinal vein occlusion.

Method

A case report.

Results

Intravitreal dexamethasone implant injection had been performed for macular edema due to left superior temporal vein branch occlusion to the left eye of a 78-year-old male patient. The slit-lamp examination 85 days later revealed that the dexamethasone implant was intralenticular. The best-corrected visual acuity (BCVA) was 0.16 on the Snellen chart. Cataract surgery was decided on for the cataract as there was no anterior chamber inflammation, the intraocular pressure (IOP) was normal, and the macular edema had resolved. Uneventful phacoemulsification within the bag intraocular lens placement was performed.

Conclusions

Accidental intralenticular Ozurdex injection is an extremely rare complication. The surgeon must decide whether to continue to observe or intervene immediately when such a complication is encountered. Cataract surgery can be planned if the macular edema has resolved and a cataract has developed. It is important to evaluate the posterior capsule with ultrasound biomicroscopy and Scheimpflug imaging before the cataract surgery to ensure a safe surgical procedure.

Immortal Ozurdex: A 10-month follow-up of an intralenticular implant

A 78-year-old male who had received a dexamethasone implant (Ozurdex, Allergan, Inc., Irvine, CA, USA) 15 days back for recalcitrant diabetic macular edema in the left eye came to us for a second opinion. On examination, his corrected distance visual acuity was 20/20 in the right eye and 20/40 in the left eye. Early cataractous changes were present in both eyes. The intraocular pressure was within normal limits. The Ozurdex implant was seen lodged in the posterior cortex of the crystalline lens in the left eye, confirmed on anterior segment optical coherence tomography (OCT) and ultrasound biomicroscopy. Fundus examination showed moderate nonproliferative diabetic retinopathy in both eyes with macular edema and epiretinal membrane in the left eye, confirmed on OCT. The patient was noncompliant and returned after 10 months. Interestingly, the implant was still present in the same location with the same vision and anterior segment findings as before. The OCT showed a reduction in macular edema. The patient was advised regular follow-up and cataract surgery at a later date.

Location of a Dexamethasone Implant at the Macula after Intravitreal Injection in a Silicone Oil-Filled Eye

Here, we report a case with cystoid macular edema (CME) due to central retinal vein occlusion (CRVO) presented with a dexamethasone implant (Ozurdex) trapped at the macula in her silicone oil- (SO-) filled eye after injection. No additional complications such as intraocular pressure (IOP) rise or retinal damage were observed. The CME was resolved during the follow-up period. At the last visit, 3 months following the injection, Ozurdex implant was found to be mostly dissolved without any additional ocular complications.

"Magic Bullet": Eccentric Macular Hole as a Complication from Dexamethasone Implant Insertion

Introduction. Intravitreal drug injections and implants are generally safe but do carry some risk, from both the procedure itself and adverse effects of the medications. We report a case of an eccentric macular hole after dexamethasone implant (Ozurdex®) administration. Ex vitro force testing was performed to evaluate dexamethasone implant injection force. Methods. Five dexamethasone implant (Ozurdex) applicators were placed 16 mm from a force plate and the force of the injected dexamethasone pellet was recorded in Newtons. Four dexamethasone implant applicators were placed 16 mm from a force plate in a basic saline solution and the force of the pellet was recorded. Results. Average maximum force in air was 0.77 N and 0.024 N in a basic saline solution (BSS). Conclusion. We present a case report of an eccentric macular hole after dexamethasone implant administration. We hypothesize a mechanical injury to the retina during insertion caused the macular hole. Force testing done in air demonstrated sufficient force from the pellet injection to cause retinal damage though injections done in BSS showed reduced forces.

Intravitreal Injection of Ozurdex(®) Implant in Patients with Persistent Diabetic Macular Edema, with Six-Month Follow-Up

AIM

To evaluate the efficacy of intravitreal dexamethasone injections in diabetic macular edema (DME).

METHODS

A 700 μg slow-release intravitreal dexamethasone implant (Ozurdex®) was placed in the vitreal cavity of 17 patients (19 eyes) affected with persistent DME. Best corrected visual acuity (BCVA) was assessed through Early Treatment Diabetic Retinopathy Study (ETDRS). Central macular thickness (CMT) was measured by spectral-domain optical coherence tomography. BCVA and CMT examinations were carried out at baseline (T0) and repeated after three days, one month (T1), three months (T3), four months (T4), and six months (T6) post injection.

RESULTS

Dexamethasone implant induced an improvement in ETDRS at T1, T3, T4, and T6 post injection. CMT was reduced at T1, T3, and T4, while at T6, CMT values were not statistically different from baseline. No complications were observed during the follow-up.

CONCLUSION

Our data suggest that dexamethasone implant is effective in reducing DME symptoms within a six-month frame.

Retinal and vitreous hemorrhage after traumatic impact of dexamethasone implant in a vitrectomized eye

PURPOSE

To report a case of retinal and vitreous hemorrhage after intravitreal injection of dexamethasone implant (0.7 mg Ozurdex) and its management.

METHODS

A 49-year-old man treated for diabetic macular edema developed vitreous and retinal hemorrhage after intravitreal injection of dexamethasone implant caused by a retinal impact during the injection procedure.

RESULTS

Retinal and vitreous hemorrhage absorbed spontaneously after 3 months. No retinal damage was detected. Intraocular pressure increased to 38 mm Hg after the injection and was well-controlled by medical therapy (dorzolamide hydrochloride-timolol maleate ophthalmic solution administered BID and oral acetazolamide 250 mg once a day). Since the surgeon performed the injection carefully without exerting any pressure on the eye, a device malfunction likely caused the implant to be injected too powerfully.

CONCLUSIONS

Vitreous and retinal hemorrhage can occur after direct impact of an Ozurdex implant against the retina during the injection. So far this has never been described in the literature. Intraocular pressure elevation can worsen due to trabecular blockage by red blood cells. Spontaneous resolution can occur but vitrectomy is a therapeutic option if the hemorrhage persists.

VITREOMACULAR TRACTION AFTER DEXAMETHASONE INTRAVITREAL IMPLANT (OZURDEX) INJECTION: THE EFFECT OF ANOMALOUS POSTERIOR VITREOUS DETACHMENT

PURPOSE

To describe an unusual macular complication after dexamethasone intravitreal implant (Ozurdex) injection.

METHODS

Case history and macular optical coherence tomography findings are described. The report describes a patient with proliferative diabetic retinopathy and vitreoschisis who received Ozurdex treatment for diabetic macular edema.

RESULTS

After Ozurdex injection, visual acuity worsened because of newly formed vitreomacular traction that was demonstrated on optical coherence tomography imaging. A mechanism is proposed by which the medication might have contributed to this outcome.

CONCLUSION

In this patient with vitreoschisis, a thickened posterior hyaloid membrane and traction developed after Ozurdex injection. The authors recommend careful evaluation of the macula before injection, particularly in diabetic patients with vitreoschisis.

Intravitreal Dexamethasone Implant for Treatment of Refractory Behçet Posterior Uveitis: One-year Follow-up Results

PURPOSE

To investigate the results of dexamethasone (DEX) implant in the treatment of eyes with refractory Behçet posterior uveitis.

METHODS

A total of 17 eyes of 12 patients with active Behçet posterior uveitis were enrolled in the study. A single intravitreal injection of DEX implant was applied to each eye. Best corrected visual acuity (BCVA), central macular thickness (CMT), vitreous haze score, and intraocular pressure (IOP) were determined, at baseline and control visits of months 1, 3, 6, and 12.

RESULTS

The mean BCVA was significantly increased from baseline at each control visit (all p < 0.05). The mean CMT and vitreous haze score were significantly decreased from baseline at each control visit (all p < 0.05). Three eyes showed IOP spikes requiring topical anti-glaucomatous treatment.

CONCLUSIONS

A single injection of DEX implant was safe and effective, as an additional treatment to systemic immunomodulatory drugs, in the treatment of refractory Behçet posterior uveitis, for a 6-month period.

Dexamethasone intravitreal implant in the treatment of diabetic macular edema

Diabetic macular edema (DME) resembles a chronic, low-grade inflammatory reaction, and is characterized by blood–retinal barrier (BRB) breakdown and retinal capillary leakage. Corticosteroids are of therapeutic benefit because of their anti-inflammatory, antiangiogenic, and BRB-stabilizing properties. Delivery modes include periocular and intravitreal (via pars plana) injection. To offset the short intravitreal half-life of corticosteroid solutions (~3 hours) and the need for frequent intravitreal injections, sustained-release intravitreal corticosteroid implants have been developed. Dexamethasone intravitreal implant provides retinal drug delivery for ≤6 months and recently has been approved for use in the treatment of DME. Pooled findings (n=1,048) from two large-scale, randomized Phase III trials indicated that dexamethasone intravitreal implant (0.35 mg and 0.7 mg) administered at ≥6-month intervals produced sustained improvements in best-corrected visual acuity (BCVA) and macular edema. Significantly more patients showed a ≥15-letter gain in BCVA at 3 years with dexamethasone intravitreal implant 0.35 mg and 0.7 mg than with sham injection (18.4% and 22.2% vs 12.0%). Anatomical assessments showed rapid and sustained reductions in macular edema and slowing of retinopathy progression. Phase II study findings suggest that dexamethasone intravitreal implant is effective in focal, cystoid, and diffuse DME, in vitrectomized eyes, and in combination with laser therapy. Ocular complications of dexamethasone intravitreal implant in Phase III trials included cataract-related events (66.0% in phakic patients), intraocular pressure elevation ≥25 mmHg (29.7%), conjunctival hemorrhage (23.5%), vitreous hemorrhage (10.0%), macular fibrosis (8.3%), conjunctival hyperemia (7.2%), eye pain (6.1%), vitreous detachment (5.8%), and dry eye (5.8%); injection-related complications (eg, retinal tear/detachment, vitreous loss, endophthalmitis) were infrequent (<2%). Dexamethasone intravitreal implant offers a viable treatment option for DME, especially in cases that are persistent or treatment (anti-vascular endothelial growth factor/laser) refractory.

Kinematic study of ozurdex injection in balanced salt solution: modeling the behavior of an injectable drug delivery device in vitrectomized eyes

PURPOSE

To analyze the kinematics of a dexamethasone intravitreal implant, Ozurdex, after its injection in a balanced salt solution (BSS) at different release angles to simulate its movement in BSS/aqueous-filled eyes.

METHODS

Eighteen Ozurdex implants were injected into a BSS-filled box at different release angles (15°, 30°, 45°), using 6 implants/group. The movement of injected implants was recorded by a high-speed video camera. Each implant's trajectory was graphically demonstrated by plotting over time. By using a distance-time function graph, the implant's velocity and normalized energy were calculated.

RESULTS

The high-speed video revealed that implants injected at 15° followed a more horizontal trajectory compared to those injected from 30° and 45°, respectively. The implant injected at 15° also achieved the highest mean initial velocity and mean initial normalized energy. The implant velocity from each injection angle decreased exponentially over time and reached nearly zero at 0.1 s. An injection of the implant at a flatter angle was also associated with higher mean retinal impact normalized energy.

CONCLUSIONS

An implant injected at a flatter angle tends to travel farther in the horizontal plane and has more initial velocity, which theoretically generates higher initial normalized energy and retinal impact normalized energy. The accidental injection at a flatter angle, which results in shortening of the effective travel distance, may carry the potential risk of direct retinal injury from the injected implant. The amount of energy necessary to cause direct retinal injury, and whether this would be clinically significant, requires further study.

Penetration force, geometry, and cutting profile of the novel and old Ozurdex needle: the MONO study

PURPOSE

To investigate the geometry, penetration force, and cutting profile of the novel and old needle of the drug delivery system (DDS) for Ozurdex injections in a standardized laboratory setting.

METHODS

In this experimental study, the normative geometrical data of the DDS needle were systematically analyzed according to nomenclature DIN 13097 (ISO 7864) and ISO 9626. The force to penetrate a standardized 0.4-mm-thick polyurethane foil was measured by a penetrometer, when the needle was piercing, cutting, and sliding through the foil and plotted as a load-displacement diagram. Magnified images of the consecutive cut were taken after the entire penetration through the foil.

RESULTS

In this experimental study, the mean point length was equal to 3.34 mm (3.28-3.36 mm) for the old DDS needle versus 3.33 mm (3.30-3.36 mm) for the new DDS needle. The secondary bevel length was 1.64 mm (1.42-1.73 mm) for the new and 1.66 mm (1.62-1.69 mm) for the old needle. The primary angle was 9.2° (9.0°-9.5°) for the old and 8.9° (8.5°-9.0°) for the new needle, respectively. The secondary bevel angle was 117.2° (116°-118°) for the old and 111.4° (110°-113°) for the new needle. The mean penetration force of the old DDS needles was significantly higher at all phases of the penetration experiment: The mean piercing force was 0.7 Newton (N) with the old and 0.47 N with the new DDS needle. The mean cutting force was remarkable higher with 1.1 N for the old DDS needle versus 0.78 N for the new DDS needle. The dilatation phase was not statistically significant between 0.94 and 0.99 N in both DDS needles. The friction phase was maintained at significantly higher levels with the old DDS needle of 0.47 N, whereas it returned to the lowest measurements of 0.11 N with the new DDS needle. Both DDS systems induced a characteristic chevron-shaped incision.

CONCLUSION

A comparison of the old and new DDS needles demonstrated a reduced penetration force with the modified new DDS needle, which may help to achieve a smooth penetration through the human sclera.

Functional and anatomical results after a single intravitreal Ozurdex injection in retinal vein occlusion: a 6-month follow-up -- the SOLO study

PURPOSE

To evaluate the efficacy of intravitreal dexamethasone implants in eyes with cystoid macular oedema (CME) secondary to branch retinal vein occlusion (BRVO) or central retinal vein occlusion (CRVO) in the clinical everyday practice, examine the effects of early retreatment and compare the results with the GENEVA study.

METHODS

The charts of 102 patients (102 eyes) with CME secondary to BRVO (n = 54) or CRVO (n = 48) treated with Ozurdex at 8 centres were retrospectively reviewed. The patients were examined monthly over a 24-week period. Slit-lamp biomicroscopy, measurement of best-corrected visual acuity (BCVA) and measurement of the central retinal thickness (CRT) with spectral-domain optical coherence tomography (SD-OCT) were performed at baseline and at every follow-up examination. With progression of the disease (loss of one line or increased central retinal thickness (CRT) of 150 μm), a reinjection of Ozurdex or anti-VEGF was offered. Additional supplementing sectorial or panretinal laser photocoagulation was considered based on the individual status of the retina.

RESULTS

In the BRVO group, the median BCVA was 0.6 logMAR (Snellen equivalent of 0.25) at baseline and improved to 0.4 logMAR (Snellen equivalent of 0.40) after 4 weeks, 0.3 logMAR (Snellen equivalent of 0.50) after 8 weeks, 0.4 logMAR (Snellen equivalent of 0.40) after 12 weeks, 0.5 logMAR (Snellen equivalent of 0.32) after 16 weeks, 0.4 logMAR (Snellen equivalent of 0.40) after 20 weeks and 0.45 logMAR (Snellen equivalent of 0.35) after 24 weeks. The mean CRT was 559 ± (SD) 209 μm at baseline and it decreased to 335 ± 148 μm after 4 weeks, 316 ± 137 μm after 8 weeks, 369 ± 126 μm after 12 weeks, 407 ± 161 μm after 16 weeks, 399 ± 191 μm after 20 weeks and 419 ± 196 μm after 24 weeks. In the CRVO group, the median BCVA was 0.7 logMAR (Snellen equivalent of 0.20) at baseline and improved to 0.4 logMAR (Snellen equivalent of 0.40) after 4 weeks, 0.4 logMAR (Snellen equivalent of 0.40) after 8 weeks, 0.6 logMAR (Snellen equivalent of 0.25) after 12 weeks, 0.6 logMAR (Snellen equivalent of 0.25) after 16 weeks, 0.5 logMAR (Snellen equivalent of 0.32) after 20 weeks and 0.52 logMAR (Snellen equivalent of 0.30) after 24 weeks. The mean CRT at baseline was 740 ± 351 μm and it decreased to 419 ± 315 μm after 4 weeks, 352 ± 261 μm after 8 weeks, 455 ± 251 μm after 12 weeks, 497 ± 280 μm after 16 weeks, 468 ± 301 μm after 20 weeks and 395 ± 234 μm after 24 weeks. The BCVA improvement was statistically significantly better (p < 0.05) compared with baseline in both groups at every follow-up visit. The mean CRT maintained significantly better when compared with baseline in both groups at all follow-up visits. Early reinjection was indicated in BRVO in 40.7% after 17.5 ± 4.2 weeks and in CRVO in 50% after 17.68 ± 4.2. Six eyes (11%) with BRVO received a sectorial laser photocoagulation at a mean interval of 22 ± 5.0 weeks. Seven eyes (15%) with CRVO received a panretinal laser photocoagulation after a mean interval of 18 ± 7.0 weeks. The BCVA improvement and the mean CRT reduction were statistically significant (p < 0.05) compared with baseline in both groups at every follow-up visit.

CONCLUSIONS

Dexamethasone intravitreal implant resulted in a significant improvement of the BCVA and reduction of CME in patients with BRVO or CRVO. Early retreatment after 16 weeks instead of 24 weeks, like in the GENEVA study, was indicated in 50% to stabilize the improved functional and anatomical results.

Preliminary results of an intravitreal dexamethasone implant (Ozurdex®) in patients with persistent diabetic macular edema

BACKGROUND

To evaluate the efficacy and safety of an intravitreal dexamethasone implant (Ozurdex®; Allergan Inc, Irvine, CA, USA) in patients with persistent diabetic macular edema (DME) over a 6-month follow-up period.

METHODS

Seventeen patients (20 eyes) affected by DME were selected. The mean age was 67 + 8 years, and the mean duration of DME was 46.3 + 18.6 months. The eligibility criteria were: age ≥ 18, a best-corrected visual acuity between 5 and 40 letters, and macular edema with a thickness of ≥275 μm. Thirteen patients had also previously been treated with anti-vascular endothelial growth factor medication.

RESULTS

The mean ETDRS (Early Treatment Diabetic Retinopathy Study) value went from 18.80 + 11.06 (T0) to 26.15 + 11.03 (P = 0.04), 28.15 + 10.29 (P = 0.0087), 25.95 + 10.74 (P = 0.045), 21.25 + 11.46 (P = 0.5) in month 1, 3, 4, and 6, respectively. The mean logMAR (logarithm of the minimum angle of resolution) value went from 0.67 + 0.23 (at T0) to 0.525 + 0.190 (P = 0.03), 0.53 + 0.20 (P = 0.034), and 0.56 + 0.22 (P = 0.12) in month 1, 3, and 4, respectively, to finally reach 0.67 + 0.23 in month 6. The mean central macular thickness value improved from 518.80 + 224.75 μm (at T0) to 412.75 + 176.23 μm, 292.0 + 140.8 μm (P < 0.0001), and 346.95 + 135.70 (P = 0.0018) on day 3 and in month 1 and 3, respectively, to then increase to 476.55 + 163.14 μm (P = 0.45) and 494.25 + 182.70 μm (P = 0.67) in month 4 and 6.

CONCLUSION

The slow-release intravitreal dexamethasone implant, Ozurdex, produced significant improvements in best-corrected visual acuity and central macular thickness from the third day of implant in DME sufferers, and this improvement was sustained until the third month.