Acute Hemorrhagic Retinopathy following Intravitreal Melphalan Injection for Retinoblastoma: A Report of Two Cases and Technical Modifications to Enhance the Prevention of Retinal Toxicity

Varied toxicity profile of intravitreal melphalan in two retinoblastoma eyes

Retinoblastoma (RB) is the most common primary intraocular malignant tumor of childhood. Persistent or recurrent vitreous seeding is the most common reason for therapeutic failure in advanced RB. Intravitreal chemotherapy has emerged as an effective therapy for vitreous seeding in RB, with a generally acceptable safety profile. However, intravitreal chemotherapeutics, especially melphalan, can cause toxicity that may progress to total retinal atrophy. In this report, we present two cases with retinal melphalan toxicity that had varied clinical findings. One of the cases had extensive retinal atrophy that was demonstrated by hand-held spectral domain optical coherence tomography (HHSD-OCT), while the other had normal retinal anatomy on HHSD-OCT but markedly diminished retinal function on flash electroretinography.

INTRAVITREAL MELPHALAN INJECTION AS A SECOND-LINE LOCAL THERAPY IN VITREORETINAL LYMPHOMA: Case Series

PURPOSE

To evaluate the effectiveness and safety of intravitreal melphalan (IVM) injection therapy in vitreoretinal lymphoma.

METHODS

Eight eyes of five biopsy-proven vitreoretinal lymphoma patients who were treated with IVM injection as a second-line therapy after intravitreal methotrexate and rituximab injections were retrospectively evaluated between January 2011 and March 2023.

RESULTS

The medical records of five vitreoretinal lymphoma patients (mean age of 62 years at the diagnosis) including 4 (80%) female patients and 1 (20%) male patient were retrospectively analyzed. Three patients (60%) either had a history of central nervous lymphoma or developed it during the follow-up. Patients were previously treated with a mean of five cycles of monthly intravitreal methotrexate and rituximab injections. All eyes showed complete response by the disappearance of vitreal and/or subretinal neoplastic cells within 6 weeks after IVM injections (range, 1-4 injections per eye). Of 12 IVM injections, 3 (25%) injections were associated with macular edema diagnosed on optical coherence tomography at 1-month follow-up and resolved spontaneously within 5 months. The IVM administration induced new retinal pigment epithelium changes in three eyes (37%).

CONCLUSION

Intravitreal melphalan injection may be effective in the management of vitreoretinal lymphoma as a second-line local therapy. Randomized clinical trials with larger numbers of patients are needed to establish the efficacy, treatment protocol, and safety of IVM injection.

Ocular and systemic toxicity of high-dose intravitreal topotecan in rabbits: Implications for retinoblastoma treatment

Although many more eyes of children with retinoblastoma are salvaged now compared to just 10 years ago, the control of vitreous seeding remains a challenge. The introduction of intravitreal injection of melphalan has enabled more eyes to be salvaged safely but with definite retinal toxicity. Intensive treatment with high-dose intravitreal topotecan may be a strategy to control tumor burden because of its cell cycle-dependent cytotoxicity and the proven safety in humans. Therefore, we evaluated the ocular and systemic safety of repeated high-dose intravitreal injections of topotecan in rabbits. Systemic and ocular toxicity was assessed in non-tumor-bearing rabbits after four weekly injections of three doses of topotecan (10μg, 25μg, and 50μg) or vehicle alone. Animals were evaluated weekly for general and ophthalmic clinical status. One week after the last injection, vitreous and plasma samples were collected for drug quantification and the enucleated eyes were subjected to histological assessment. Weight, hair loss, or changes in hematologic values were absent during the study period across all animal groups. Eyes injected with all topotecan doses or vehicle showed no signs of anterior segment inflammation, clinical or histologic evidence of damage to the retina, and ERG parameters remained unaltered throughout the study. Vitreous and plasma topotecan lactone concentrations were undetectable. Four weekly intravitreal injections of topotecan up to 50μg in the animal model or a 100μg human equivalent dose were not toxic for the rabbit eye. High doses of topotecan may show promising translation to the clinic for the management of difficult-to-treat retinoblastoma vitreous seeds.

A Rare Case of Acute Hemorrhagic Retinopathy Following Intravitreal Melphalan Injection for Persistent Vitreous Seeds in Retinoblastoma

Purpose:

This report describes a case of acute occlusive hemorrhagic complication after intravitreal melphalan for vitreous seeds in retinoblastoma.

Methods:

A case report is presented.

Results:

Intravitreal melphalan has been used extensively for vitreous seeds in retinoblastoma. Although melphalan is relatively safe at optimal doses, it can sometimes cause inadvertent complications like hemorrhagic events if the drug is administered close to the retina or in more pigmented eyes. We report a case of a 5-month-old patient with bilateral retinoblastoma who underwent enucleation of the right eye and 2 intravitreal melphalan injections in the left eye (20 µg/0.02 mL) at a 1-month interval for persistent vitreous seeds. After the second injection, there was a sudden decrease in the child’s visual acuity in the left eye, and the retina showed multiple intraretinal hemorrhages and diffuse chorioretinal atrophy.

Conclusion:

Intravitreal melphalan may cause acute hemorrhagic complications after intravitreal use for retinoblastoma seeds, especially in pigmented eyes.

Evaluation of intravitreal topotecan dose levels, toxicity and efficacy for retinoblastoma vitreous seeds: a preclinical and clinical study

Background

Current melphalan-based intravitreal regimens for retinoblastoma (RB) vitreous seeds cause retinal toxicity. We assessed the efficacy and toxicity of topotecan monotherapy compared with melphalan in our rabbit model and patient cohort.

Methods

Rabbit experiments: empiric pharmacokinetics were determined following topotecan injection. For topotecan (15 μg or 30 µg), melphalan (12.5 µg) or saline, toxicity was evaluated by serial electroretinography (ERG) and histopathology, and efficacy against vitreous seed xenografts was measured by tumour cell reduction and apoptosis induction. Patients: retrospective cohort study of 235 patients receiving 990 intravitreal injections of topotecan or melphalan.

Results

Intravitreal topotecan 30 µg (equals 60 µg in humans) achieved the IC₉₀ across the rabbit vitreous. Three weekly topotecan injections (either 15 µg or 30 µg) caused no retinal toxicity in rabbits, whereas melphalan 12.5 µg (equals 25 µg in humans) reduced ERG amplitudes 42%–79%. Intravitreal topotecan 15 µg was equally effective to melphalan to treat WERI-Rb1 cell xenografts in rabbits (96% reduction for topotecan vs saline (p=0.004), 88% reduction for melphalan vs saline (p=0.004), topotecan vs melphalan, p=0.15). In our clinical study, patients received 881 monotherapy injections (48 topotecan, 833 melphalan). Patients receiving 20 µg or 30 µg topotecan demonstrated no significant ERG reductions; melphalan caused ERG reductions of 7.6 μV for every injection of 25 µg (p=0.03) or 30 µg (p<0.001). Most patients treated with intravitreal topotecan also received intravitreal melphalan at some point during their treatment course. Among those eyes treated exclusively with topotecan monotherapy, all eyes were salvaged.

Conclusions

Taken together, these experiments suggest that intravitreal topotecan monotherapy for the treatment of RB vitreous seeds is non-toxic and effective.

Vitreous Seed Classification and Regression Patterns in Eyes With Retinoblastoma

Purpose:

This work subclassifies retinoblastoma vitreous seeds and evaluates the efficacy, regression patterns, and adverse effects of combination intravitreal melphalan and topotecan chemotherapy for resistant and recurrent vitreous seeds.

Methods:

A retrospective review of medical records was conducted of patients with retinoblastoma and resistant or recurrent vitreous seeds who were treated with intravitreal melphalan and topotecan injections from August 2014 to July 2018. Main outcome measures included regression pattern, time for regression, time for recurrence of seeds, treatment outcomes, and ocular toxicity.

Results:

Nineteen eyes received 138 intravitreal injections over 74 treatment sessions (mean, 7.26 injections per eye); vitreous seeds regressed in 18 eyes. Of cloud vitreous seeds, curvilinear (n = 2) and sphero-linear (n = 2) subtypes were observed. During regression, some sphere seeds showed an intermediary streak-like pattern and took longer to regress (mean, 11.13 ± 14.05 months and 11.67 ± 8.62 injections) than those without the intermediary streak-like pattern (mean, 3.55 ± 2.57 months and 4.2 ± 1.87 injections). Mean follow-up was 34.87 ± 21.09 months (median, 35 months; range, 11-96 months). Anterior segment toxicity was seen in 10 (53%) eyes and posterior segment toxicity in 5 (26%) eyes. Kaplan-Meier survival estimates for globe salvage at 2 years was 94% and 73% at 5 years. Kaplan-Meier survival for vitreous seed–free status was 94% at 2 years and 65% at 5 years.

Conclusions:

An expanded vitreous seed classification system that further subcategorizes hitherto unrecognized vitreous seed morphology is needed. An intermediate streaking process results in a prolonged regression time for sphere vitreous seeds.

Intravitreal Melphalan for Retinoblastoma: The Impact of Toxicity on Recurrence and Ultimate Globe Salvage

Introduction

Intravitreal melphalan (IVM) has emerged as an efficacious treatment for vitreous seeding in retinoblastoma. Although rarely severe, IVM-related toxicity may be treatment limiting. There is paucity of data on the impact of IVM toxicity on new tumor formation and ultimate globe salvage.

Objectives

To investigate whether the grade of retinal toxicity post-IVM impacts retinal and seeding tumor recurrence, as well as the overall ability to salvage the eye.

Methods

A single-institution retrospective chart review was performed on 47 eyes of 42 patients who received systemic intravenous chemotherapy followed by IVM as salvage treatment for persistent or recurrent vitreous seeding. Chorioretinal toxicity was graded from 0 to 5.

Results

Toxicity grade was inversely associated with the risk of recurrence, where a one-unit increase in toxicity grade correlated with nearly a 54% reduction in the odds of tumor recurrence (OR 0.46 [0.25-0.84], p = 0.01). Similarly, toxicity grade was related to enucleation, where a one-unit increase in toxicity grade was associated with a 31% reduction in the odds of undergoing enucleation (OR 0.69 [0.40-1.18], p = 0.17).

Conclusions

While retinoblastoma therapy aims to limit toxicity, especially visually significant toxicity, eyes with higher grades of post-IVM toxicity are less likely to have retinal and seeding tumor recurrence.

Progressive Preretinal Fibrosis with Late, Ossifying, Proliferative Retinopathy following Treatment for Retinoblastoma

We report a case of retinal atrophy and progressive preretinal fibrosis in an eye previously treated with intravenous and intra-arterial chemotherapy (IAC), which evolved immediately after treatment with intravitreal injection of melphalan. The atrophy and fibrosis progressed later to proliferative retinopathy with dystrophic ossification. The patient was originally diagnosed with bilateral retinoblastoma at 4 months of age and was treated with systemic chemotherapy followed by IAC. New vitreous seeds developed and required treatment with intravitreal chemotherapy. There was resolution of vitreous seeding after 2 doses of intravitreal melphalan, but clinically the eye developed new, widespread retinal atrophy and fibrosis within 1 month of the second injection. This was followed by phthisis and late proliferative retinopathy nearly 1 year later. Retinoblastoma specialists should be aware of this potential complication of combined chemotherapy treatments.

Intravitreal melphalan therapy for vitreous seeds in retinoblastoma: Implementation and outcomes of a new chemotherapy protocol

Retinoblastoma is the most common paediatric ocular tumour, which appears in the retina. Without treatment, retinoblastoma grows and destroys the internal ocular globe architecture, even leading to metastasis. When treated, overall survival is close to 97%, the alkylating drug melphalan being the most extensively used chemotherapeutic agent in localised treatment. The aim of this study is to describe the implementation of a new intravitreal chemotherapy retinoblastoma treatment protocol for children implanting vitreous seeds through intravitreal melphalan injections and to evaluate the patients' health outcomes treated with it. Between December 2014 and July 2018, seven patients were treated with this protocol. They received a mean of 3.3 cycles of intravitreal melphalan with standard doses of 30 mcg per cycle. In the seven eyes treated in our hospital, the response was as expected; three eyes with vitreous seedings (43%) were successfully treated. The main adverse effects presented by all patients were scars at cryogenisation points. In two patients, the appearance of 'salt and pepper' retinopathy was reported. Oncology pharmacists, as part of the treatment team, can provide information about recommended doses, expected adverse effects, stability of preparations, most appropriate method of processing, packaging, and methods of drug administration, to ensure efficacy and especially safety in the administration of these drugs.

Conservative management of retinoblastoma: Challenging orthodoxy without compromising the state of metastatic grace. "Alive, with good vision and no comorbidity"

Retinoblastoma is lethal by metastasis if left untreated, so the primary goal of therapy is to preserve life, with ocular survival, visual preservation and quality of life as secondary aims. Historically, enucleation was the first successful therapeutic approach to decrease mortality, followed over 100 years ago by the first eye salvage attempts with radiotherapy. This led to the empiric delineation of a window for conservative management subject to a "state of metastatic grace" never to be violated. Over the last two decades, conservative management of retinoblastoma witnessed an impressive acceleration of improvements, culminating in two major paradigm shifts in therapeutic strategy. Firstly, the introduction of systemic chemotherapy and focal treatments in the late 1990s enabled radiotherapy to be progressively abandoned. Around 10 years later, the advent of chemotherapy in situ, with the capitalization of new routes of targeted drug delivery, namely intra-arterial, intravitreal and now intracameral injections, allowed significant increase in eye preservation rate, definitive eradication of radiotherapy and reduction of systemic chemotherapy. Here we intend to review the relevant knowledge susceptible to improve the conservative management of retinoblastoma in compliance with the "state of metastatic grace", with particular attention to (i) reviewing how new imaging modalities impact the frontiers of conservative management, (ii) dissecting retinoblastoma genesis, growth patterns, and intraocular routes of tumor propagation, (iii) assessing major therapeutic changes and trends, (iv) proposing a classification of relapsing retinoblastoma, (v) examining treatable/preventable disease-related or treatment-induced complications, and (vi) appraising new therapeutic targets and concepts, as well as liquid biopsy potentiality.

Posterior Vitreous Detachment and the Associated Risk of Retinal Toxicity with Intravitreal Melphalan Treatment for Retinoblastoma

BACKGROUND/AIMS

The presence of a posterior vitreous detachment (PVD) may play a role in the development of severe retinal toxicity following intravitreal melphalan (IVM) injection for vitreous seeding. We aimed to evaluate the incidence of PVD in retinoblastoma eyes and its association with retinal toxicity after IVM.

METHODS

We reviewed 112 eyes of 81 retinoblastoma patients with B-scan images available for review from 2010 to 2017. A cohort with vitreous seeding treated with IVM was compared to a cohort that did not undergo injection. The primary outcome measure was the presence of PVD at diagnosis and after treatment. Secondary measures included IVM-associated retinal toxicity and other ocular complications.

RESULTS

The incidence of PVD was 20% at diagnosis, and in eyes with B-scans available both at diagnosis and after treatment 18% of eyes developed a PVD over the course of therapy, more frequently after IVM (p = 0.05). Of 34 eyes receiving IVM treatment, the incidences of posterior segment toxicity and globe salvage were similar between eyes with and without PVD (p = 0.4015 and 0.52, respectively).

CONCLUSION

In this cohort of patients, there did not appear to be an association with the presence of PVD during IVM and the development of retinal toxicity.

Ocular toxicity of intravitreal melphalan for retinoblastoma in Chinese patients

Background

To evaluate the efficacy, complications, and clinical characteristics, including the ocular toxicity, of intravitreal melphalan(IVM) treatment for vitreous seeding in Chinese retinoblastoma patients.

Methods

This was a retrospective, non-comparative analysis including 30 consecutive eyes of 23 patients with viable persistent or recurrent vitreous seeding following retinoblastoma treatment. All of the eyes received IVM injections (20–33 μg). Vitreous seeding control, determination of the ocular toxicity, and the clinical characteristics of intravitreal melphalan treatments were observed.

Results

The mean patient age at the time of the injection was 28 months (median = 22 months, range = 12–50 months). In total, 80 injections were administered in 30 eyes, the overall enucleation-free survival rate was 83.3% (25/30). The complications included retinal pigment epithelium (RPE) and choroidal atrophy (19/30, 63.3%), pupillary synechiae (13/30, 43.3%), iris atrophy (12/30, 40%), retinal vascular occlusion (12/30, 40.0%), optic atrophy (6/30, 20%), vitreous hemorrhage (3/30, 10%), persistent hypotonia and phthisis bulbi (4/30 13.3%), and cataracts (8/30, 26.6%). Twelve eyes demonstrated grade 3 or greater IVM-associated retinal or anterior segment toxicity post injection. Mean dosage given showed significant difference between the groups. There were no significant differences in the retinal toxicity grades regarding the seed classification or seed regression patterns.

Conclusions

Intravitreal melphalan is an effective treatment for refractory vitreous seeding from retinoblastoma, but exhibits both anterior and posterior segment toxicity in Chinese patients.

Co-delivery of miR-181a and melphalan by lipid nanoparticles for treatment of seeded retinoblastoma

Melphalan is an efficient chemotherapeutic agent that is currently used to treat retinoblastoma (Rb); however, the inherent risk of immunogenicity and the hazardous integration of this drug in healthy cells is inevitable. MicroRNAs are short non-coding single-stranded RNAs that affect a vast range of biological processes. Previously, we focused on the regulatory role of miR-181a during cancer development and progression. In this manuscript, 171 nm switchable lipid nanoparticles (LNP) co-delivered melphalan and miR-181a with encapsulation efficiencies of 93%. Encapsulation of melphalan in LNP significantly improved its therapeutic efficiency. Gene analysis shows that miR-181a decreases the expression of anti-proliferative gene MAPK1 and anti-apoptotic gene Bcl-2, but significantly increased the expression of pro-apoptotic gene BAX. Our results suggest that the two agents have a complementary effect in reducing the viability of cultured Rb cells (primary and cell line) and decreasing Rb cell counts in an in-vivo xenograft Rb model in rats. Our results suggest that the proposed co-delivery technique significantly increases the therapeutic impact, allows for lower administration of melphalan, and consequently, could minimize the cytotoxic side-effects of this drug.

Targeting HMGA protein inhibits retinoblastoma cell proliferation

We describe a novel synthetic strategy for conjugating HMGA2 siRNA and the HMGA aptamer to the nucleolin aptamer and nucleolin antibody, respectively. Our studies demonstrate that these conjugates inhibit cell proliferation in retinoblastoma cells.

A novel approach to target HMGA proteins in retinoblastoma using HMGA2 siRNA–nucleolin aptamer and HMGA aptamer–nucleolin antibody conjugates was developed.

Integrated Treatment during the Intravitreal Melphalan Era: Concurrent Intravitreal Melphalan and Systemic Chemoreduction

Background

Intravitreal injection of melphalan (IVM) is safe and effective for the treatment of seeding in retinoblastoma. Current protocols require weekly injections during examination under anesthesia (EUA). To avoid additional anesthesia exposure for these children, IVM was initiated at the EUA concurrent with the 4th cycle of systemic chemoreduction in a series of 6 patients with persistent seeding.

Methods

A retrospective review was completed to assess treatment response compared to all patients at our center treated with IVM and systemic chemotherapy. Overall, 6 eyes of 6 patients were included; salvage therapy included systemic chemoreduction with vincristine, etoposide, and carboplatin and IVM for persistent seeding.

Results

IVM was initiated in all eyes at cycle 4 of their chemotherapy. Success in eradicating vitreous seeds was 100%; overall salvage rate was 67%. Anterior toxicity was observed in 2 out of 6 eyes and posterior toxicity in 4 out of 6 eyes.

Conclusion

The concurrent chemoreduction and IVM protocol demonstrated a similar efficacy of globe salvage while sparing children additional EUAs. However, the increased rates of observed melphalan-related toxicities for concurrent therapy are concerning. Further clinical experience is necessary to define the best initiation time and dosing schedule for IVM.

Retinoblastoma for Pediatric Ophthalmologists

Retinoblastoma can present in 1 or both eyes and is the most common intraocular malignancy in childhood. It is typically initiated by biallelic mutation of the RB1 tumor suppressor gene, leading to malignant transformation of primitive retinal cells. The most common presentation is leukocoria, followed by strabismus. Heritable retinoblastoma accounts for 45% of all cases, with 80% being bilateral. Treatment and prognosis of retinoblastoma is dictated by the disease stage at initial presentation. The 8th Edition American Joint Committee on Cancer (AJCC) TNMH (tumor, node, metastasis, heritable trait) staging system defines evidence-based clinical and pathological staging for overall prognosis for eye(s) and child. Multiple treatment options are available in 2018 for retinoblastoma management with a multidisciplinary team, including pediatric ocular oncology, medical oncology, radiation oncology, genetics, nursing, and social work. Survival exceeds 95% when disease is diagnosed early and treated in centers specializing in retinoblastoma. However, survival rates are less than 50% with extraocular tumor dissemination. We summarize the epidemiology, genetics, prenatal screening, diagnosis, classification, investigations, and current therapeutic options in the management of retinoblastoma.

Long-term outcomes of Group D retinoblastoma eyes during the intravitreal melphalan era

BACKGROUND

To evaluate outcomes of Group D retinoblastoma (Rb) eyes during the intravitreal melphalan era.

PROCEDURE

Retrospective chart review of patients diagnosed with Group D Rb from 2011 to 2016 was done. Overall, 76 Group D eyes of 68 patients were included; salvage therapy included systemic chemoreduction with vincristine, etoposide, and carboplatin with local consolidation, followed by intravitreal injection of melphalan for recurrent or persistent seeding. External beam radiation was not used as a treatment modality. Primary outcome measurement was globe salvage.

RESULTS

Of 76 Group D eyes, 24 were enucleated primarily and 52 were treated with intent to salvage the globe. Systemic chemoreduction salvaged 25 of 52 eyes (48%). Tumor recurrences were diagnosed in 27 eyes (52%); five with massive retinal recurrences underwent enucleation and 22 were treated with intravitreal melphalan injection. Of the 22 injected eyes, 14 (64%) were salvaged and eight required enucleation primarily for retinal recurrences. Success in eradicating vitreous seeds was 100%. The Kaplan-Meier 3-year survival estimate for treated eyes is 76.5% (95% CI: 61.4-86.3). Median follow-up for the group of 76 Group D eyes was 29.5 months (SD 17.9 months).

CONCLUSION

During a 6-year period that included the initiation of intravitreal melphalan at our institution, the salvage rate of treated Group D eyes was 75% (39/52 eyes). Intravitreal melphalan was utilized for ocular salvage in 42% (22/52 eyes). Systemic chemoreduction combined with intravitreal melphalan for seeding demonstrated a high overall salvage rate for Group D eyes in this cohort.

Not All Seeds Are Created Equal: Seed Classification Is Predictive of Outcomes in Retinoblastoma

OBJECTIVE

Intravitreal chemotherapy has emerged as an important modality for treating vitreous seeding in retinoblastoma. A classification system has been described as predictive of response to intravitreal melphalan (IVM) in patients treated predominantly with primary intra-arterial chemotherapy. The objective of this study is to evaluate the outcomes of retinoblastoma treated with intravenous chemotherapy and IVM as salvage for vitreous seeding, and further to determine whether vitreous seed classification (dust, spheres, cloud) is predictive of the total number and dose of IVM injections required for treatment in this cohort.

DESIGN

A nonrandomized retrospective review.

PARTICIPANTS

Retinoblastoma patients treated at a single center with intravenous chemotherapy and IVM.

METHODS

Retrospective review of patients with vitreous seeding from retinoblastoma treated with intravenous chemotherapy and IVM from 2012 to 2016.

MAIN OUTCOME MEASURES

Primary outcome measure was eradication of seeds and globe salvage. Secondary measures included IVM-associated toxicity and complications.

RESULTS

Overall, 28 eyes of 25 patients were included, with a total of 110 IVM injections. By seed classification, eyes with dust (n = 15) required a median of 3 injections, spheres (n = 8) required 4 injections, and clouds (n = 5) required 6 injections. Spherical seeds were only seen in recurrent vitreous seeding. Of the 28 treated eyes, 9 were enucleated, 6 for recurrent retinal disease, resulting in an overall globe salvage rate of 68%. The salvage rate secondary to active retinoblastoma was 79%. Dust classification was the most prevalent seeding type of the 9 enucleated eyes. There was 100% regression of vitreous seeds after intravitreal injection and no eye was treated with radiation or enucleated for seeding. Twelve eyes demonstrated grade 3 or greater IVM-associated retinal or anterior segment toxicity post injection. Mean follow-up was 33 months (range, 9-51 months).

CONCLUSIONS

IVM is an effective treatment for vitreous seeding after intravenous chemotherapy for retinoblastoma. As with eyes treated with intra-arterial chemotherapy, seed classification is predictive of the total number and dose of IVM injections in eyes treated with intravenous chemotherapy. Eyes with clouds required significantly more injections than eyes with dust or spheres.