Ocular Therapeutics and Molecular Delivery Strategies for Neovascular Age-Related Macular Degeneration (nAMD).

Age-related macular degeneration (AMD) is the leading cause of vision loss in geriatric population. Intravitreal (IVT) injections are popular clinical option. Biologics and small molecules offer efficacy but relatively shorter half-life after intravitreal injections. To address these challenges, numerous technologies and therapies are under development. Most of these strategies aim to reduce the frequency of injections, thereby increasing patient compliance and reducing patient-associated burden. Unlike IVT frequent injections, molecular therapies such as cell therapy and gene therapy offer restoration ability hence gained a lot of traction. The recent approval of ocular gene therapy for inherited disease offers new hope in this direction. However, until such breakthrough therapies are available to the majority of patients, antibody therapeutics will be on the shelf, continuing to provide therapeutic benefits. The present review aims to highlight the status of pre-clinical and clinical studies of neovascular AMD treatment modalities including Anti-VEGF therapy, upcoming bispecific antibodies, small molecules, port delivery systems, photodynamic therapy, radiation therapy, gene therapy, cell therapy, and combination therapies.

Evaluation of Month-24 Efficacy and Safety of Epimacular Brachytherapy for Previously Treated Neovascular Age-Related Macular Degeneration: The MERLOT Randomized Clinical Trial.

Importance: Although anti-vascular endothelial growth factor (VEGF) treatment offers better outcomes than the natural history of neovascular age-related macular degeneration (ARMD), a less burdensome, less expensive, and more durable treatment is needed. Objective: To assess the efficacy and safety of epimacular brachytherapy (EMB) for chronic, active, neovascular ARMD. Design, Setting, and Participants: The Macular Epiretinal Brachytherapy vs Ranibizumab (Lucentis) Only Treatment (MERLOT) pivotal device trial was conducted at 24 National Health Service hospitals across the UK. Patients who had neovascular ARMD and received intravitreal ranibizumab were enrolled between November 10, 2009, and January 30, 2012. Eligible patients were randomized 2:1 and were stratified by lens status and angiographic lesion type to receive either EMB plus as-needed ranibizumab or as-needed ranibizumab monotherapy. Participants were followed up monthly for 24 months and then assessed at a final visit at month 36. Masking of participants and clinicians was not possible, but best-corrected visual acuity (BCVA) and imaging were analyzed by masked assessors. Analysis followed the intent-to-treat approach. Interventions: Pars plana vitrectomy with 24 Gy EMB plus as-needed ranibizumab vs as-needed ranibizumab monotherapy. Main Outcomes and Measures: Coprimary outcomes were the number of as-needed ranibizumab injections and the mean change in Early Treatment Diabetic Retinopathy Study (ETDRS) BCVA with a noninferiority margin of -5 ETDRS letters. Secondary outcomes were the percentage of participants losing fewer than 15 ETDRS letters and gaining 0 or more or 15 or more ETDRS letters and the mean change in angiographic total lesion size, choroidal neovascularization size, and foveal thickness on optical coherence tomography. Results: Of 363 participants, 329 (90.6%) completed 24 months of follow-up (222 participants in the EMB group and 107 in the ranibizumab group). The mean (SD) age of the combined groups was 76.5 (7.4) years. The mean (SD) number of ranibizumab injections was 9.3 (6.7) in the EMB group and 8.3 (4.5) in the ranibizumab group, with a difference of 1.0 injection (95% CI, -0.3 to 2.3; P = .13). The mean (SD) BCVA change was -11.2 (15.7) ETDRS letters in the EMB group and -1.4 (10.9) ETDRS letters in the ranibizumab group, with a difference of 9.8 ETDRS letters (95% CI, -6.7 to -12.9). In the EMB group, 65.6% of participants (160 of 244) lost fewer than 15 ETDRS letters vs 86.6% (103 of 119) in the ranibizumab group, with a difference of 21% (95% CI, 12.4%-29.5%; P < .001). Microvascular abnormalities occurred in 20 of 207 eyes (9.7%) in the EMB group and 1 of 97 eyes (1.0%) in the ranibizumab group. These abnormalities occurred outside the foveal center, and there were no unexpected safety concerns. Conclusions and Relevance: The MERLOT trial found that despite the acceptable safety of EMB, it did not reduce the number of ranibizumab injections and was associated with worse visual acuity than anti-VEGF treatment alone; these results do not support EMB use as an adjunct treatment for chronic, active neovascular ARMD. Trial Registration: ClinicalTrials.gov Identifier: NCT01006538.

Subfoveal Choroidal Thickness as a Potential Predictor of Clinical Response to Stereotactic Radiotherapy for Neovascular Age-Related Macular Degeneration.

BACKGROUND AND OBJECTIVE: Stereotactic radiotherapy (SRT) is a new adjuvant treatment modality that has been shown to reduce the need for repetitive intravitreal injections (IVIs) in patients with neovascular age-related macular degeneration (nAMD). The authors aimed to determine baseline predictors of clinical response to SRT. PATIENTS AND METHODS: This was a retrospective, observational case series of patients with nAMD who underwent SRT and subsequently had at least 12 months of complete follow-up. After SRT and one mandatory IVI, patients were examined every 4 weeks and received further treatment on a pro re nata basis. Examination included enhanced depth imaging spectral-domain optical coherence tomography (SD-OCT) to measure subfoveal choroidal thickness (SFCT) and central macular thickness (CMT). Patients' data were retrieved from medical records and included demographics, disease duration, lesion size, best-corrected visual acuity (BCVA), previous number of IVIs, and type of drug applied. RESULTS: A total of 35 eyes of 35 patients (76.23 years ± 7.05 years) were included, and 21 eyes (60%) responded well to SRT. The annual injection rate decreased from 6.86 before SRT to 3.46 afterward, whereas BCVA improved from 0.49 logMAR at baseline to 0.37 logMAR at final follow-up. From a morphologic point of view, CMT and SFCT decreased by 71 µm and 37 µm, respectively, at 12-month follow-up compared to baseline. Of all investigated parameters, only SFCT proved to be significant, as a higher baseline SFCT was found to be a strong negative predictor for the number of IVIs needed after SRT (regression coefficient: -0.678; P < .001). CONCLUSIONS: Baseline SFCT may help predict which patients with nAMD will respond more favorably to SRT. The authors found eyes with a thicker baseline SFCT needed fewer IVIs after SRT. [Ophthalmic Surg Lasers Imaging Retina. 2018;49:320-328.].

One-year results from clinical practice of epimacular strontium-90 brachytherapy for the treatment of subfoveal choroidal neovascularization secondary to AMD.

BACKGROUND AND OBJECTIVE: To evaluate clinical feasibility, safety, and efficacy of epiretinal strontium-90 brachytherapy in subfoveal choroidal neovascularization (CNV) due to age-related macular degeneration (AMD) in eyes unresponsive to repeated anti-VEGF injections. PATIENTS AND METHODS: A retrospective, single-center study on patients treated with strontium-90 brachytherapy for CNV secondary to neovascular AMD. Patients underwent pars plana vitrectomy with a single 24 Gy dose brachytherapy. They were re-treated with anti-VEGF injections on an as-needed basis if subretinal or intraretinal fluid was detected on optical coherence tomography imaging. RESULTS: Twenty-two patients were treated, and 20 completed 12 months of follow-up. Ten patients maintained stable vision, eight gained vision, and two lost more than three Snellen lines. The mean best corrected visual acuity change from baseline was -8 ± 5.7 letters. A mean of 5.5 ± 4.4 anti-VEGF injections were administered throughout 12 months. CONCLUSION: Epimacular brachytherapy is feasible in clinical practice. While some patients benefit from the treatment and need significantly fewer as-needed injections, others appear not to react to irradiation treatment after 1 year of follow-up. Larger numbers of patients are needed to evaluate therapeutic efficacy and to determine which patients can benefit from combined radiation and anti-VEGF therapy.

Proton beam irradiation for non-AMD CNV: 2-year results of a randomised clinical trial.

AIMS: To evaluate safety and visual outcomes after proton beam irradiation (PBI) therapy for subfoveal choroidal neovascularisation (CNV) secondary to causes other than age-related macular degeneration (AMD). METHODS: This study is a prospective, unmasked and randomised clinical trial using two dosage regimens, conducted in the Massachusetts Eye and Ear Infirmary. The study included 46 patients with CNV secondary to non-AMD and best-corrected visual acuity of 20/320 or better. Patients were randomly assigned to receive 16 or 24 cobalt gray equivalents (CGE) of PBI in two equal fractions. Complete ophthalmological examinations, fundus photography and fluorescein angiography were performed at baseline and 6, 12, 18 and 24 months after treatment. RESULTS: At 1 year after treatment, 82% and 72% lost fewer than 1.5 lines of vision in the 16 CGE and in 24 CGE groups, respectively. At 2 years after therapy, 77% in the lower dose group and 64% in the higher dose group lost fewer than 1.5 lines of vision. Mild radiation complications such as radiation vasculopathy developed in 17.6% of patients. CONCLUSIONS: PBI is a safe and efficacious treatment for subfoveal CNV not due to AMD. The data with respect to visual outcomes and radiation complications trend in favour of the 16 CGE group, although differences do not reach statistical significance. PBI may be considered as an alternative to current therapies.

Ten-year follow-up of eyes treated with stereotactic fractionated external beam radiation for neovascular age-related macular degeneration.

PURPOSE: To determine the long-term effects of stereotactic fractionated external beam radiation on eyes treated for neovascular age-related macular degeneration. METHODS: A retrospective review of all eyes treated with stereotactic fractionated external beam radiation (20-40 Gy, 2-Gy fractions) between 1997 and 2000 was performed to identify eyes with ≥ 2-year follow-up for analysis. A subset was imaged prospectively using a high-resolution Fourier-domain optical coherence tomography. RESULTS: Among 94 eyes treated, 33 eyes (32 subjects) had ≥ 2-year follow-up information (mean follow-up, 6.2 years; range, 2-10 years). Final visual acuity ranged from 20/50 to no light perception. Final macular findings included central geographic atrophy (49%), disciform scar (30%), and active choroidal neovascular membrane (9%). Fourier-domain optical coherence tomography images of three eyes with geographic atrophy revealed photoreceptor layer loss within areas of geographic atrophy with intact retinal morphology in areas of radiation exposure outside geographic atrophy. Radiation retinopathy was suspected in 18% and confirmed by fluorescein angiography in 15%, ranging from mild to neovascular glaucoma/phthisis bulbi (2 eyes). Mean time from stereotactic fractionated external beam radiation to development of radiation retinopathy was 5.4 years (range, 1-10 years). CONCLUSION: A moderate rate of delayed radiation retinopathy was noted in eyes with neovascular age-related macular degeneration treated with stereotactic fractionated external beam radiation. Geographic atrophy was a common finding.

Overview of radiation trials for age-related macular degeneration.

Radiotherapy is a promising adjunctive tool to antiangiogenesis therapies for control of the choroidal neovascularization that characterizes exudative (wet) age-related macular degeneration. Historically, radiation monotherapy sufficient to effectively eradicate choroidal neovascularization has been associated with mixed results; however, newer techniques and delivery platforms have been developed to improve efficacy. The most significant improvements are technical advances that improve the precision of energy delivery, so that tissue destruction remains confined to the target. In addition, several combination therapies are showing promise for enhanced effect. Other strategies, such as pretreating neovascular tissue to increase its sensitivity to radiation, thereby reducing the energy dose, may also be viable. However, even though the modern delivery systems permit relatively low dosages, there are risks of radiotherapy to ocular tissue, and its role remains speculative, pending results of ongoing trials.

Pathology beyond neovascularization: new targets in age-related macular degeneration.

Control of choroid neovascularization may be important but insufficient to preserve long-term vision threatened by age-related macular degeneration. A retrospective analysis of patients who were early participants in anti-vascular endothelial growth factor studies, other pathologic processes, particularly fibrosis and atrophy, have participated in vision loss independent of new vessel growth. The recent interest in combination treatment strategies has been dominated by more effective blockade of angiogenic signaling, but it may also be necessary to incorporate therapies that block fibrosis, inhibit atrophy or other pathophysiologic processes not directly related to neovascularization to achieve the ultimate goal of preserving sight for a long term.

Twelve-month safety and visual acuity results from a feasibility study of intraocular, epiretinal radiation therapy for the treatment of subfoveal CNV secondary to AMD.

PURPOSE: The purpose of this study was to evaluate the short-term safety and feasibility of intraocular, epiretinal delivery of beta radiation for the treatment of subfoveal choroidal neovascularization secondary to age-related macular degeneration for 12 months. A 3-year follow-up period is planned to assess the long-term safety of the procedure. METHODS: In this nonrandomized, multicenter feasibility study, 34 treatment-naïve patients with predominantly classic, minimally classic, or occult lesions due to subfoveal choroidal neovascularization secondary to age-related macular degeneration received a single treatment with either 15 Gray (Gy) (8 patients) or 24 Gy (26 patients) beta radiation (strontium-90) using a novel intraocular delivery device. Adverse events and safety endpoints were observed and recorded. Visual acuity was measured preoperatively and postoperatively using standard Early Treatment Diabetic Retinopathy Study vision charts. RESULTS: Twelve months after treatment, no adverse events associated with exposure to radiation were observed. All patients in both 15 Gy (n = 4) and 24 Gy cohorts (n = 17) who met inclusion criteria and were treated according to protocol lost fewer than three lines of vision. Fifty percent (2/4) of the 15 Gy-treated patients and 76% (13/17) of the 24 Gy-treated patients improved or maintained their visual acuity at 12 months. In the 24 Gy group, 29% (5/17) gained three lines or more in visual acuity. The mean change in visual acuity observed at month 12 was +10.3 letters in the 24 Gy study cohort and -1.0 letters in the 15 Gy cohort. CONCLUSION: The short-term safety and efficacy of intraocular, epiretinal delivery of beta radiation for the treatment of subfoveal choroidal neovascularization was promising in this small study group and should be studied in a larger cohort of patients.

Twelve-month short-term safety and visual-acuity results from a multicentre prospective study of epiretinal strontium-90 brachytherapy with bevacizumab for the treatment of subfoveal choroidal neovascularisation secondary to age-related macular degeneration.

BACKGROUND/AIMS: This study evaluated the short-term safety and feasibility of epiretinal strontium-90 brachytherapy delivered concomitantly with intravitreal bevacizumab for the treatment of subfoveal CNV due to AMD for 12 months. A 3-year follow-up is planned. METHODS: In this prospective, non-randomised, multicentre study, 34 treatment-naïve patients with predominantly classic, minimally classic and occult subfoveal CNV lesions received a single treatment with 24 Gy beta radiation (strontium-90) and two injections of the anti-VEGF antibody bevacizumab. Adverse events were observed. BCVA was measured using standard ETDRS vision charts. RESULTS: Twelve months after treatment, no radiation-associated adverse events were observed. In the intent-to-treat (ITT) population, 91% of patients lost <3 lines (15 ETDRS letters) of vision at 12 months, 68% improved or maintained their BCVA at 12 months, and 38% gained >/=3 lines. The mean change in BCVA observed at month 12 was a gain of 8.9 letters. CONCLUSION: The safety and efficacy of intraocular, epiretinal brachytherapy delivered concomitantly with anti-VEGF therapy for the treatment of subfoveal CNV secondary to AMD were promising in this small study population. Long-term safety will be assessed for 3 years. This regimen is being evaluated in a large, multicentre, phase III study.

Terapia fotodinámica con verteporfina en neovascularización coroidea después de cirugía refractiva / Photodynamic therapy with verteporfin in choroidal neovascularization after refractive surgery

Propósito: Analizar los resultados obtenidos usando TFD (terapia fotodinámica) con verteporfina como primera elección para tratar la NVC (neovascularización coroidea) subfoveal y yuxtafoveal en pacientes con miopía magna corregida mediante cirugía refractiva (laser-assisted in situ keratomileusis -LASIK- y lentes fáquicas de cámara anterior -LFCA-). Método: Se estudiaron catorce ojos que presentaban alta miopía a los que se les había realizado LASIK (siete casos) o implante de lente intraocular –LIO– (siete casos), que desarrollaron NVC y fueron tratados con TFD con verteporfína. Resultados: La media Mejor Agudeza Visual Corregida (MAVC) después de la cirugía fue 0,45 (DE: 0,17; rango: 0.2 a 0.8), con equivalente esférico residual (EER) -0,5 (DE: 1,8D; rango: 1 a 5,5D). La MAVC después de NVC fue 0,10 (DE: 0,19; rango: 0,025 a 0,7). NVC fue tratada con TFD (media de 2,0 DE: 0,8 tratamientos). La media MAVC mejoró hasta 0,22 (DE: 0,18; rango: 0;1 a 0,63) (EER -1,4 DE: 1,4D; rango: 0,5 a -4D). Las diferencias en EER después de cirugía refractiva y después de TFD, y las diferencias en MAVC antes y después de TFD no fueron estadísticamente significativas (p=0,82 y p=0,06, respectivamente, aplicada t de Student para datos apareados). Conclusiones: El empleo de TFD para el tratamiento de la NVC tras la cirugía refractiva permite mantener la MAVC sin inducir cambios en el equivalente esférico

Purpose: To analyze the results obtained with Photodynamic Therapy (PDT) to treat subfoveal and juxtafoveal Choroidal Neovascularization (CNV) in patients with high myopia corrected by Laser-Assisted in situ Keratomileusis (LASIK) or by implanting a Phakic Intraocular Lens (PIOL). Methods: We analyzed the results from 14 highly myopic eyes corrected by LASIK (seven cases) or by PIOL implantation (seven cases), which later developed CNV and were treated by PDT with verteporfin. Results: Mean Best Corrected Visual Acuity (BCVA) after refractive surgery was 0.45 SD 0.17 (range, 0.2 to 0.8), with residual spherical equivalent (RSE) -0.5 SD 1.8 D (range, 1 to 5.5 D). After CNV appearance, BCVA was 0.10 SD 0.19 (range, 0.025 to 0.7). CNV was treated in all cases by PDT (mean, 2.0 SD 0.8 treatments). After CNV closure, the mean BCVA improved up to 0.22 SD 0.18 (range, 0.1 to 0.63) (RSE -1.4 SD 1.4 D, range, 0.5 to –4 D). Differences in RSE after refractive surgery and after PDT, and differences between BCVA after CNV appearance and final were not statistically significant (p=0.82 and p=0.06, respectively, Student’s t test paired data). Conclusion: We consider that PDT is effective in achieving closure of CNV in myopic patients after refractive surgery without inducing changes in spherical equivalent (Arch Soc Esp Oftalmol 2008; 83: 539-544)

Proton beam irradiation for neovascular age-related macular degeneration.

OBJECTIVE: To evaluate safety and visual outcomes after proton therapy for subfoveal neovascular age-related macular degeneration (AMD). DESIGN: Randomized dose-ranging clinical trial. PARTICIPANTS: One hundred sixty-six patients with angiographic evidence of classic choroidal neovascularization resulting from AMD and best-corrected visual acuity of 20/320 or better. METHODS: Patients were assigned randomly (1:1) to receive 16-cobalt gray equivalent (CGE) or 24-CGE proton radiation in 2 equal fractions. Visual acuity was measured using standardized protocol refraction. Complete ophthalmological examinations, color fundus photography, and fluorescein angiography were performed before and 3, 6, 12, 18, and 24 months after treatment. MAIN OUTCOME MEASURE: Proportion of eyes losing 3 or more lines of vision from baseline. Kaplan-Meier statistics were used to compare cumulative rates of vision loss between the 2 treatment groups. RESULTS: At 12 months after treatment, 36 eyes (42%) and 27 eyes (35%) lost 3 or more lines of vision in the 16-CGE and 24-CGE groups, respectively. Rates increased to 62% in the 16-CGE group and 53% in the 24-CGE group by 24 months after treatment (P = 0.40). Radiation complications developed in 15.7% of patients receiving 16 CGE and 14.8% of patients receiving 24 CGE. CONCLUSIONS: No significant differences in rates of visual loss were found between the 2 dose groups. Proton radiation may be useful as an adjuvant therapy or as an alternative for patients who decline or are not appropriate for approved therapies.

Visual functioning and quality of life in the SubFoveal Radiotherapy Study (SFRADS): SFRADS report 2.

AIMS: To determine whether or not self reported visual functioning and quality of life in patients with choroidal neovascularisation caused by age related macular degeneration (AMD) is better in those treated with 12 Gy external beam radiotherapy in comparison with untreated subjects. METHODS: A multicentre single masked randomised controlled trial of 12 Gy of external beam radiation therapy (EBRT) delivered as 6 x 2 Gy fractions to the macula of an affected eye versus observation. Patients with AMD, aged 60 years or over, in three UK hospital units, who had subfoveal CNV and a visual acuity equal to or better than 6/60 (logMAR 1.0). METHODS: Data from 199 eligible participants who were randomly assigned to 12 Gy teletherapy or observation were available for analysis. Visual function assessment, ophthalmic examination, and fundus fluorescein angiography were undertaken at baseline and at 3, 6, 12, and 24 months after study entry. To assess patient centred outcomes, subjects were asked to complete the Daily Living Tasks Dependent on Vision (DLTV) and the SF-36 questionnaires at baseline, 6, 12, and 24 months after enrolment to the study. Cross sectional and longitudinal analyses were conducted using arm of study as grouping variable. Regression analysis was employed to adjust for the effect of baseline co-variates on outcome at 12 months and 24 months. RESULTS: Both control and treated subjects had significant losses in visual functioning as seen by a progressive decline in mean scores in the four dimensions of the DLTV. There were no statistically significant differences between treatment and control subjects in any of dimensions of the DLTV at 12 months or 24 months after study entry. Regression analysis confirmed that treatment status had no effect on the change in DLTV dimensional scores. CONCLUSIONS: The small benefits noted in clinical measures of vision in treated eyes did not translate into better self reported visual functioning in patients who received treatment when compared with the control arm. These findings have implications for the design of future clinical trials and studies.

Strontium plaque brachytherapy for exudative age-related macular degeneration: three-year results of a randomized study.

OBJECTIVE: To determine the efficacy of strontium plaque (Sr90) brachytherapy for age-related macular degeneration (AMD) with subfoveal choroidal neovascularization (CNV). DESIGN: Randomized clinical trial. PARTICIPANTS: Eighty-eight eyes of 86 patients with subfoveal CNV secondary to AMD were randomized either to plaque radiotherapy or to observation. INTERVENTION: Radiotherapy was given as episcleral brachytherapy using Sr90 plaques. Two different plaque types were used. Plaque I had a diameter of 8 mm and delivered a dose of 15 Gy at a depth of 1.75 mm in 54 minutes. With plaque II, the corresponding values were 4 mm, 12.6 Gy, and 11 minutes. The control group was observed without any treatment. MAIN OUTCOME MEASURES: The primary outcome measure was visual acuity at 6, 12, 24, and 36 months. Other outcome variables were contrast sensitivity, fluorescein angiographic, and clinically evaluated changes in the macula. RESULTS: Eighty-two patients (84 eyes [95%]) completed the 1-year follow-up, and 80 (93%) and 74 (86%) patients completed the 2- and 3-year follow-ups, respectively. At 6 months, visual loss of > or =3 lines occurred in 20% of treated patients and 42% of control patients (P = 0.031). At 12 months, a visual loss of > or =3 lines occurred in 45% (treated) and 56% (controls) (P = 0.325); at 24 months, in 73% and 71% (P = 0.914); and at 36 months, in 80% and 84% of patients (P = 0.591), respectively. Patients irradiated with plaque I had better results: a visual loss of > or =3 lines occurred in 6% at 6 months (P = 0.008, relative to controls), in 18% at 12 months (P = 0.007), in 59% at 24 months (P = 0.348), and in 71% at 36 months (P = 0.212). In patients treated with plaque II, the corresponding values were 29% (P = 0.032), 65% (P = 0.459), 83% (P = 0.317), and 80% (P = 0.687) at 6, 12, 24, and 36 months, respectively. CONCLUSIONS: The short-term clinical course of exudative AMD is affected by Sr90 brachytherapy, but by 12 months, there was no treatment benefit. This article contains additional online-only material available at http://www.ophsource.org/periodicals/ophtha.

Verteporfin photodynamic therapy for the treatment of persistent subfoveal choroidal neovascularization after external beam radiotherapy: one-year results.

PURPOSE: To determine the safety and efficacy of verteporfin photodynamic therapy (PDT) for the treatment of persistent choroidal neovascularization (CNV) previously treated with external beam radiotherapy (EBRT). DESIGN: Retrospective case series. METHODS: Verteporfin PDT was performed on 14 eyes of 13 patients with symptomatic leakage from CNV previously treated by EBRT. Principal outcome measures were: comparison of visual acuity at 12 months post-PDT with baseline and the recording of any ocular or systemic adverse events. RESULTS: At baseline, the mean logMAR (+/-SD) VA was 0.81 +/- 0.33, whereas at the 12-month point it was 0.89 +/- 0.43 (P = .326). At the 12-month examination 10 eyes had lost less than 3 lines of VA, and 8 eyes had lost less than 1.5 lines. During this time, there were 2.1 PDT treatment sessions per eye on average (range = 1 to 4). There were no ocular or systemic adverse events recorded. CONCLUSIONS: This short-term study shows that verteporfin PDT is safe after EBRT and may be of benefit for recalcitrant CNV.

Results of radiotherapy of subfoveal neovascularization with 16 and 20 Gy.

PURPOSE: In a nonrandomized, prospective study the efficacy of radiotherapy with 16 and 20 Gray (Gy) for subfoveal neovascularization in age-related macular degeneration (ARMD) was analysed. MATERIAL AND METHODS: From 1996 to 1998, 63 eyes were irradiated with 16 Gy and 38 eyes with 20 Gy for exudative ARMD. A total of 12 eyes had classic ARMD, 89 eyes occult ARMD, median baseline visual acuity (VA) was 6/30 (range: 3/60-6/9.5), median age was 78 years. Risk factors (type of ARMD, baseline VA) were evenly distributed in both groups. Median follow-up was 1.3 years (range: 4 months-4.7 years). VA of +/-1 line or better and unchanged size and activity of the membrane in fluorescein angiography were defined as stable. Actuarial methods were used. RESULTS: Median loss of VA was -3 lines (range: -14 to +5), neovascularization remained unchanged or decreased in size and activity in 35 eyes. At 18 months, the probability of stabilized VA was 0.4 (95% confidence interval (CI): 0.3-0.5), at 24 months 0.3 (95% CI: 0.2-0.4). Radiation dose, type of ARMD or baseline VA had no significant impact on outcome of VA and membrane size and activity (P>0.05). Side effects were mild and transient increased tearing. CONCLUSION: In this study, the results after radiotherapy were comparable to the natural course of the disease. An impact of radiation dose (16 vs 20 Gy) on stabilizing visual acuity and subfoveal neovascularization could not be shown. The results of studies on dose escalation using very small fields and high radiation doses should be awaited.

Effect of irradiation on neovascularization in rat skinfold chambers: implications for clinical trials of low-dose radiotherapy for wet-type age-related macular degeneration.

PURPOSE: Wet-type age-related macular degeneration is a refractory eye disease that involves choroidal neovascularization. Randomized controlled trials of low-dose radiotherapy for this disease performed in Japan showed that, at 12 months of follow-up, visual acuity was significantly well preserved and the neovascular membrane size decreased. Because understanding the effect of irradiation on new vascular networks is an important prerequisite for clinical trials, we used a rat skinfold chamber technique to investigate X-ray-induced changes in neovasculature microcirculation. METHODS AND MATERIALS: Neovascularization was induced in rat skinfold chambers via polyvinyl chloride resin plates. Neovessels were irradiated in a single 10-Gy dose, after which, changes in vascular density, blood velocity, tissue blood flow, and interstitial fluid pressure (IFP), were measured. RESULTS: Vascular density, tissue blood flow, and IFP measurements in resin-induced inflammatory tissue were much higher than those measurements in normal tissue. Although overall blood velocity was low and sluggish or blood-flow stasis occurred in the neovascular network, after a single 10-Gy dose of radiation, the velocity increased, stasis improved markedly, and many dilated vessels narrowed. Thereafter, vascular density, blood flow, and IFP significantly decreased and approached normal values. CONCLUSION: These findings may help explain clinical results related to radiotherapy-induced changes in neovascular membranes in age-related macular degeneration. Both vascular morphology and vascular function in inflammatory tissue returned to normal, without vessel destruction, after an appropriate radiation dose.