External beam radiation therapy for choroidal neovascularization

Ranibizumab plus fufang xueshuantong capsule versus ranibizumab alone for exudative age-related macular degeneration

Objective

To compare the efficacy of ranibizumab plus fufang xueshuantong capsule (cFXST) with the efficacy of ranibizumab alone in treatment of exudative age-related macular degeneration.

Methods

This prospective, randomized, controlled, pilot study included 38 eyes from 38 patients with exudative age-related macular degeneration (AMD) that were randomly allocated into two cohorts of 19 eyes each: ranibizumab (C_r) and ranibizumab plus cFXST (C_fr). All patients received three monthly injections of ranibizumab. Patients in C_fr also received daily oral supplementation of cFXST. Best corrected visual acuity (BCVA) and thickness of the choroidal neovascularization-pigment epithelial detachment (CNV-PED) complex (measured by optical coherence tomography) were recorded at baseline and at 1 and 3 months after the first intravitreal injection of ranibizumab.

Results

In the C_fr, the CNV-PED complex thickness was reduced by 31.7% and 36.1% at 1 and 3 months, respectively; these reductions were significantly greater than the 19.7% and 24.2% reductions in the C_r. BCVA improvement was significantly greater in the C_fr than in the C_r after 3 months; the proportion of patients with functional response was also greater in the C_fr than in the C_r (16/16 vs. 8/17).

Conclusion

Oral cFXST increases the efficacy of short-term ranibizumab treatment for exudative AMD.

Phase I/II Randomized Study of Proton Beam with Anti-Vascular Endothelial Growth Factor for Exudative Age-Related Macular Degeneration: One-Year Results

OBJECTIVE

To assess the safety and efficacy of proton beam therapy (PBT) as an adjunct to intravitreal anti-vascular endothelial growth factor (VEGF) for the treatment of exudative age-related macular degeneration.

DESIGN

Phase I/II, interventional, prospective, randomized, sham-controlled double-blinded study.

PARTICIPANTS

Eyes with newly diagnosed exudative age-related macular degeneration with vision between 20/40 and 20/400 were included. Exclusion criteria included diabetes or other ocular comorbidities affecting vision.

METHODS

Eyes were randomized to receive either 16 GyE, 24 GyE, or sham PBT. All eyes had 3 monthly intravitreal anti-VEGF treatments, followed by monthly visits with treatments as needed.

MAIN OUTCOME MEASURES

Mean change in best-corrected visual acuity (BCVA), mean number of anti-VEGF injections, proportion of eyes with >15 letters BCVA decrease, proportion of eyes developing radiation retinopathy or papillopathy, proportion of eyes with cataract progression, and mean changes central retinal thickness on OCT and lesion size on angiography at 1 year.

RESULTS

Of 30 enrolled eyes, 22 completed follow-up monthly for 12 months for analysis. The BCVA improved by a mean of 8 letters (0.48±0.36 logarithm of the minimum angle of resolution) overall from baseline. Overall, central retinal thickness decreased from 340±155 to 246±48 (P = 0.008) at 12 months. The mean change in BCVA and central retinal thickness was not different among the 3 study groups. The mean number of anti-VEGF injections at 12 months was 6.13 for sham irradiation arm, 5.52 in the 16 GyE arm, and 3.83 for the 24 GyE arm (P = 0.004 between sham and 24 GyE). No eye had severe visual loss, radiation retinopathy, or papillopathy.

CONCLUSIONS

No safety issue was noted associated with combining 16 GyE or 24 GyE PBT with intravitreal anti-VEGF therapy in eyes with exudative age-related macular degeneration. Overall improvements in BCVA and imaging parameters were not affected by the addition of PBT, but the number of anti-VEGF treatments needed was significantly lower with the addition of 24 GyE PBT.

Context for Protons as Adjunctive Therapy in Neovascular Age-Related Macular Degeneration: A Review

In the last few years we have witnessed increasing availability of proton therapy in the United States and worldwide. As a result, proton therapy is considered as either a primary or adjunctive approach for numerous indications where conventional radiation therapy shows promise but is accompanied by toxicities. Age-related macular degeneration (AMD) remains the leading cause of adult blindness in industrialized nations, and third worldwide, following cataract and glaucoma. Current standard therapy is intravitreal injection of anti-vascular endothelial growth factor agents. While this treatment shows improvement and stabilization in visual acuity for 40% of patients, 60% still experience disease progression. These injections are costly, necessitate repeated office visits, and carry the risk of endophthalmitis. The pathophysiology underlying neovascular AMD (nAMD) underscores the need to simultaneously target multiple pathways to retain useful vision. Radiation can be antiangiogenic, anti-inflammatory, and antiproliferative. Early photon therapy clinical trials were heterogeneous, and a Cochrane review of data demonstrated usefulness in treatment of nAMD but recommended further studies. Advantages of proton therapy over photon therapy include the ability to deliver a focal dose to the target while minimizing dose to normal structures, which is enhanced by unique treatment planning software that uses fluorescein angiography to verify target location and allows conformation of dose to the irregular shape and thickness characteristic of choroidal neovascular membranes, the pathognomonic finding in nAMD. Preliminary data suggest a potential role for proton therapy in the treatment of nAMD. In this article we review previous treatments for AMD, including those with both photon and proton radiation, and recommend future directions for clinical investigations to evaluate the role of proton therapy as an adjunct to antiangiogenic therapy, the current standard of care in this challenging setting.

Current knowledge and trends in age-related macular degeneration: today's and future treatments

PURPOSE

To address the most dynamic and current issues concerning today's treatment options and promising research efforts regarding treatment for age-related macular degeneration. This review is aimed to serve as a practical reference for more in-depth reviews on the subject.

METHODS

An online review of the database PubMed and Ovid were performed, searching for the key words age-related macular degeneration, AMD, VEGF, treatment, PDT, steroids, bevacizumab, ranibizumab, VEGF-trap, radiation, combined therapy, as well as their compound phrases. The search was limited to articles published since 1985. All returned articles were carefully screened, and their references were manually reviewed for additional relevant data. The web page www.clinicaltrials.gov was also accessed in search of relevant research trials.

RESULTS

A total of 363 articles were reviewed, including 64 additional articles extracted from the references. At the end, only 160 references were included in this review.

CONCLUSION

Treatment for age-related macular degeneration is a very dynamic research field. While current treatments are mainly aimed at blocking vascular endothelial growth factor, future treatments seek to prevent vision loss because of scarring. Promising efforts have been made to address the dry form of the disease, which has lacked effective treatment.

Radiation therapy for neovascular age-related macular degeneration

In the enormity of the public health burden imposed by age-related macular degeneration (ARMD), much effort has been directed toward identifying effective and efficient treatments. Currently, anti-vascular endothelial growth factor (VEGF) injections have demonstrated considerably efficacy in treating neovascular ARMD, but patients require frequent treatment to fully benefit. Here, we review the rationale and evidence for radiation therapy of ARMD. The results of early photon external beam radiation therapy are included to provide a framework for the sequential discussion of evidence for the usage of stereotactic radiation therapy, proton therapy, and brachytherapy. The evidence suggests that these 3 modern modalities can provide a dose-dependent benefit in the treatment of ARMD. Most importantly, preliminary data suggest that all 3 can be used in conjunction with anti-VEGF therapeutics, thereby reducing the frequency of anti-VEGF injections required to maintain visual acuity.

Treatment of polypoidal choroidal vasculopathy with photodynamic therapy. 2002

PURPOSE

To study the effects of photodynamic therapy using verteporfin in the treatment of patients with subfoveal polypoidal choroidal vasculopathy (PCV).

METHODS

A retrospective chart review of 16 consecutive patients with subfoveal PCV treated with photodynamic therapy using verteporfin was performed.

RESULTS

The mean age of the patients involved was 70.5 years. The mean follow-up time was 12 months. The visual acuity improved in 9 (56.3 %), remained the same in 5 (31.3 %), and decreased in 2 (12.5 %). The mean change in visual acuity was an improvement of 2.38 lines, a difference that was highly significant (P = 0.004). The change in visual acuity was negatively correlated with increasing age. The final visual acuity was positively correlated with initial acuity and negatively correlated with age. These results were confirmed by multiple linear regression. No patient had any lasting complication from the treatment.

CONCLUSIONS

Subfoveal PCV has no proven method of treatment. Although the follow-up time and the number of patients in this pilot study were limited, the encouraging results and lack of complications suggest that further study is indicated.

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.

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.

A phase I trial of stereotactic external beam radiation for subfoveal choroidal neovascular membranes in age-related macular degeneration

Effective treatment for neovascular age-related macular degeneration (AMD) is currently limited. Radiation therapy, a therapeutic approach with known antiangiogenic properties, has been investigated as a modality to prevent severe visual loss in AMD. Most of the studies using external beam radiation employed <25 Gy to the whole eye, which is below the dose of radiation that is toxic to the retina and optic nerve ( approximately 50 Gy and approximately 59 Gy, respectively). Stereotactic fractionated external beam radiation (St-EBR) is a method that allows radiation to be delivered to a small, defined area. We investigated the effects of St-EBR in incremental doses up to 40 Gy on neovascular AMD. Patients with clinical signs and fluorescein angiography demonstrating neovascular AMD, visual acuity (VA) better than 20/400 and ineligible for laser treatment (MPS criteria) or who refused to have laser photocoagulation were enrolled in the study. Each patient was treated with radiation at incremental dosages from 20 Gy to 40 Gy. After completion of the radiation course, all patients were followed-up at 3 and 7 weeks and 3, 6, and 12 months. Best-corrected VA (ETDRS), slit-lamp and fluorescein angiographic evaluations were performed at each visit. 94 eyes of 89 patients were treated from October 1997 to April 2000. The VA was 0.82+/-0.35 before treatment, 0.83+/-0.36 at 6 months, and 0.89+/-0.33 at 12 months. No patients suffered any significant acute side effects. No significant benefits in either VA or in membrane size were derived from increasing the doses of radiation. Our results are consistent with trends of a palliative benefit of radiotherapy in neovascular AMD and support further investigation of radiotherapy. Since there is no evidence that therapeutic effectiveness is dose dependent, our data provide no justification for potentially dangerous escalations in radiation dosage for treating neovascular AMD.

Result of Photodynamic Therapy for Idiopathic Subfoveal Choroidal Neovascularization

PURPOSE

To investigate the factors that affect final vision following photodynamic therapy (PDT) for idiopathic subfoveal choroidal neovascularization (CNV).

METHODS

A retrospective review of 16 patients whose eyes were diagnosed as idiopathic subfoveal CNV and were followed up for a minimum of 9 months. Statistical analysis was performed to investigate relationships between sex, age, size of the lesion, and initial vision compared to final vision.

RESULTS

In the PDT group (10 eyes), the mean age of the patients was 34 years, mean size of the lesion was 1300 microm, mean initial vision was 20/60, and 7 of the 10 patients (70%) showed more than a two-line improvement in vision. Factors affecting final vision were sex (p=0.049), initial vision (p=0.0455), and size of the lesion (p=0.006). In the observation group (6 eyes), the mean age of the patients was 39 years, mean size of the lesion was 575 microm, mean initial vision was 20/32, and 5 of the 6 patients (83%) showed more than a two-line improvement in vision.

CONCLUSIONS

The prognosis of idiopathic CNV was favorable as was reported in other studies. In the PDT group, statistically significant factors affecting final vision were initial vision, size of the lesion, and sex. However, since the number of patients sampled was insufficient and the average size of the lesions in the female patients was smaller, the size of the lesion seems to be the most important factor.

The age-related macular degeneration radiotherapy trial (AMDRT): one year results from a pilot study

PURPOSE

To assess the short-term safety and efficacy of treating subfoveal choroidal neovascularization (CNV) with external beam radiation delivered in 5 x 4 Gy fractions among patients having age-related macular degeneration (AMD).

DESIGN

A multicenter prospective randomized controlled pilot study.

METHODS

Eighty-eight patients were enrolled through 10 sites and were randomized to radiotherapy (20 Gy delivered in 5 daily fractions of 4 Gy each; 6 MV [N = 41]) or no radiotherapy (sham radiotherapy [N = 22] or observation [N = 25]). Eligibility criteria included visual acuity of at least 20/320 and subfoveal CNV not amenable to treatment. Randomization was stratified by lesion type (new or recurrent CNV) and blood (<50% or >/=50% of the lesion [N = 13]). The primary outcome measure was loss of >/=3 lines of visual acuity. Secondary outcome measures were angiographic response and side effects.

RESULTS

At baseline, patient and ocular characteristics were similar between treatment groups. At six months, 9 radiated eyes (26%) and 17 eyes not radiated (49%) lost >/=3 lines of visual acuity (P = .04; stratified chi(2) test). At 12 months, 13 radiated eyes (42%) and 9 observed eyes (49%) lost >/=3 visual acuity lines (P = .60). The radiated group demonstrated smaller lesions and less fibrosis than the nonradiated group (P = .05 and .004, respectively) at 12 months. Radiation-induced complications were not observed except for one radiated eye with numerous cotton wool spots and possible radiation retinopathy.

CONCLUSIONS

External beam radiation at 5 x 4 Gy may have a modest and short-lived (six month) benefit in preserving visual acuity.

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.

Incidence of laser photocoagulation and photodynamic therapy with verteporfin at a tertiary retinal center

PURPOSE

To examine the influence of photodynamic therapy (PDT) with verteporfin on the indication and frequency of conventional thermal krypton laser photocoagulation in choroidal neovascularization.

METHODS

A retrospective chart review was performed comparing laser indication and frequency 1 year before and 2 years after PDT started to be used routinely following the guidelines of the Treatment of Age-Related Macular Degeneration with Photodynamic Therapy Study Group and the Verteporfin in Photodynamic Therapy Study Group.

RESULTS

Similar frequencies of laser treatment were seen in the year before and during the first year after PDT was commenced (301 [7.1% of all patients] to 281 [6.9%]). In the year thereafter, however, there was a marked decrease in laser treatments (174 [3.9%]). Interestingly, there was a steady increase in the relative frequency of laser treatments of extrafoveal and parapapillary lesions in the years after PDT was commenced (29.2%, year 1; 30.6%, year 2; and 39.6%, year 3).

CONCLUSION

PDT has led to a decrease in conventional laser photocoagulation at one large tertiary retinal center in Austria. Moreover, it is our belief that patients are now referred at earlier stages of the disease, which has resulted in a shift in thermal laser indications.

Polypoidal choroidal vasculopathy

Polypoidal choroidal vasculopathy was first described as a peculiar hemorrhagic disorder of the macula, characterized by recurrent sub-retinal and sub-retinal pigment epithelium bleeding in middle aged black women. The use of indocyanine green angiography and subsequently of optical coherent tomography has widened our ability to study and understand the pathophysiology of this disorder. The primary abnormality involves the choroidal circulation, and the characteristic lesion is an inner choroidal vascular network of vessels ending in an aneurysmal bulge or outward projection, visible clinically as a reddish orange, spheroid, polyp-like structure. We have also recognized that individuals of African-American and Asian descents are more at risk for developing polypoidal choroidal vasculopathy as the disorder seems to preferentially affect pigmented individuals. However, it has been shown that while that still holds true, patients of other racial backgrounds may be afflicted. Particularly, polypoidal choroidal vasculopathy has been found to be present in about 8-13% of white patients with clinical appearance of exudative age-related macular degeneration. Polypoidal choroidal vasculopathy has also been reported in Irish, French, German, and Italian patients. The natural course of the disease often follows a remitting-relapsing course, and clinically, it is associated with chronic, multiple, recurrent serosanguineous detachments of the retinal pigment epithelium and neurosensory retina with long-term preservation of good vision. Photodynamic treatment appears to be a promising alternative to conventional laser therapy, for the treatment of polypoidal choroidal vasculopathy. In conclusion, polypoidal choroidal vasculopathy seems to be a distinct clinical entity that should be differentiated from other types of choroidal neovascularization associated with age-related macular degeneration and other known choroidal degenerative, inflammatory, and ischemic disorders.

Radiotherapy for recurrent choroidal neovascularisation complicating age related macular degeneration

AIMS

To report the safety and visual outcome data of external beam irradiation for recurrent choroidal neovascularisation complicating age related macular degeneration.

METHODS

Eighteen consecutive eyes received external beam irradiation with seven fractions of 2 Gy (total dose 14 Gy). The next 16 consecutive eyes received external beam irradiation with five fractions of 3 Gy (total dose 15 Gy). Main outcome measure was change in visual acuity. Secondary outcome variables were contrast sensitivity and fundus photographic/fluorescein angiographic progression.

RESULTS

The 3 Gy fraction group lost fewer lines of distance visual acuity at the three and six month follow up. At one year follow up, this difference was not maintained with 2 Gy fraction and 3 Gy fraction eyes. At one year follow up a decrease in visual acuity of three or more lines (moderate visual loss) occurred in 58% of 2 Gy and 42% of 3 Gy fraction eyes (p<0.36). At one year follow up a decrease in visual acuity of six or more lines (severe visual loss) occurred in 41% of 2 Gy eyes and 17% of 3 Gy eyes (p<0.23). At three months follow up, 3 Gy eyes were less likely (0%) than 2 Gy eyes (47%) to show moderate visual loss (p<0.003). However, Kaplan Meier curves estimate a significantly lower rate of severe visual loss in the 3 Gy group (p = 0.02). There were no significant differences in contrast sensitivity loss or fluorescein angiographic stabilisation rates. No evidence of radiation toxicity was observed.

CONCLUSION

Our results are consistent with trends for a palliative benefit with higher fraction sizes and doses. The radiobiologic differences between low and high fraction size groups in this study are modest and correlate with the modest and short term difference in visual outcomes. These trends support further investigation of radiotherapy using fraction sizes of 4 Gy or higher.

Current and Future Treatment Options for Nonexudative and Exudative Age-Related Macular Degeneration

Age-related macular degeneration (AMD) is the leading cause of irreversible visual loss in the industrialised world. Although relatively simple to diagnose through direct visualisation augmented with rapid sequence fluorescein angiography, treatment has presented a far greater challenge because the true aetiology of AMD is largely unknown. Within the past decade, researchers have introduced many new, potentially promising treatment and prevention options in an attempt to minimise the damage imparted from AMD. They capitalise on many of the theoretical and known factors contributing to AMD progression. A high-dose of an orally administered combination of the antioxidants ascorbic acid (vitamin C), tocopherol (vitamin E) and beta-carotene, in addition to copper and zinc, is the only widely accepted preventive therapy. Thermal laser photocoagulation and verteporfin photodynamic therapy are the only standard treatment options available based on large scale, randomised, prospective, placebo-controlled trials; however, efficacy is limited and only a minority of patients who present with AMD are eligible for these treatments. Many other preventive and treatment options are in all phases of clinical studies and expected to change the entire approach to AMD management in the near future. For example, alternative antioxidants, drusen ablation, apheresis and HMG-CoA reductase inhibitors have shown promise in some studies by preventing or slowing the progression of certain forms of AMD. In addition, alternative photodynamic therapies, low-intensity laser, antiangiogenic medications, radiation treatment and surgery have demonstrated the ability, albeit to differing degrees, to inhibit or possibly even reverse the severe vision loss often associated with AMD characterised by choroidal neovascularisation.

Review Article. New treatments in age-related macular degeneration

Age-related macular degeneration (AMD) is the leading cause of legal blindness in individuals 50 years and older in the developed world. Choroidal neovascularization (CNV) in exudative AMD is responsible for the majority of severe vision loss. Until recently, laser photocoagulation was the only well-established and widely accepted treatment for CNV. However, it is beneficial only for a small subset of patients, has a high rate of CNV persistence and recurrence and results in iatrogenic, collateral damage to the overlying retina. These issues make it difficult to recommend in the case of subfoveal lesions. Consequently, numerous experimental therapeutic interventions are under investigation with the common objective of destroying the CNV but leaving the foveal neurosensory retina intact. Treatment modalities can be grouped into five major categories: photodynamic therapy; radiotherapy; transpupillary thermotherapy; anti-angiogenic and angiostatic agents; and surgical intervention. The present review aims to explain the rationale behind these new treatments, analyse the evidence for their safety and efficacy, determine their stage of development and indicate in which patients they are potentially useful.

Current concepts and recent advances in the management of age-related macular degeneration

BACKGROUND

Age-related macular degeneration (AMD) is the leading cause of visual impairment and blindness in the Western World in those aged 65 and older. At present, several treatment modalities are utilised and several more are undergoing investigation in an attempt to retard the occurrence and progression of this devastating condition.

AIMS

To provide the non-ophthalmologist with an understanding of the current treatment options available to patients suffering from all variants of AMD.

METHODS

Medline and Embase search.

RESULTS

Several treatment modalities have been investigated and utilised in the treatment of all variants of this condition. While promising results have been reported, no treatment is ideal.

CONCLUSION

While no curative treatment for this condition currently exists, early recognition and treatment, if indicated, have been shown to reduce the risk of severe vision loss in patients with this condition.

Age-related macular degeneration: etiology, pathogenesis, and therapeutic strategies

Age-related macular degeneration is the principal cause of registered legal blindness among those aged over 65 in the United States, western Europe, Australia, and Japan. Despite intensive research, the precise etiology of molecular events that underlie age-related macular degeneration is poorly understood. However, investigations on parallel fronts are addressing this prevalent public health problem. Sophisticated biochemical and biophysical techniques have refined our understanding of the pathobiology of drusen, geographic atrophy, and retinal pigment epithelial detachments. Epidemiological identification of risk factors has facilitated an intelligent search for underlying mechanisms and fueled clinical investigation of behavior modification. Gene searches have not only brought us to the cusp of identifying the culpable gene loci in age-related macular degeneration, but also localized genes responsible for other macular dystrophies. Recent and ongoing investigations, often cued by tumor biology, have revealed an important role for various growth factors, particularly in the neovascular form of the condition. Transgenic and knockout studies have provided important mechanistic insights into the development of choroidal neovascularization, the principal cause of vision loss in age-related macular degeneration. This in turn has culminated in preclinical and clinical trials of directed molecular interventions.

Clinicopathological correlation of choroidal neovascularization after external beam radiotherapy in age-related macular degeneration

PURPOSE

To analyze the histopathology of choroidal neovascularization after external beam radiotherapy in age-related macular degeneration.

METHODS

A retrospective non-case-matched comparative histopathologic study. The histoarchitecture of nine surgically removed subretinal specimens from nine patients that had undergone external beam radiotherapy for exudative age-related macular degeneration was studied. Seven patients had received 20 Gy in 10 fractions and two 15 Gy in 5 fractions with an average time interval between radiotherapy and surgical extraction of 14 months (range 3-28). A consecutive series of classic, mixed and occult choroidal neovascular membranes served as controls.

RESULTS

Clinical findings. Radiation-associated choroidal neovasculopathy was angiographically suspected in four patients: a coarse net of vessels on fluorescein angiography developing at the border of previously irradiated choroidal neovascularization was observed in three patients; blebs at the margin of a plaque on indocyanine green angiography were observed in two patients. Pathological findings. Diffuse drusen as well as intra-Bruch's fibrovascular tissue was found in all irradiated specimens. In four specimens an edematous vascularized layer was seen between diffuse drusen and normal-appearing intra-Bruch's fibrovascular tissue. This lesion was not found in the control specimens. A particular correlation for the bleb lesion was not recognized.

CONCLUSION

The appearance of an edematous subretinal pigment epithelial vascularized layer between diffuse drusen and normal-appearing fibrovascular tissue in four of nine irradiated membranes may be secondary to previous irradiation. It may correlate with the unusual exudative manifestations observed after external beam radiotherapy.

Magnetic resonance imaging analysis of anterior and posterior eye segment displacement during ocular gaze shifts

PURPOSE

To determine the relationship between movements of the posterior and anterior eye segments during arbitrary gaze shifts and to obtain information for monitoring fixation during radiotherapy for ocular diseases.

METHODS

We examined eye movements of ten emmetropic volunteers in a 1.5 T magnetic resonance system. Using a T2-weighted ultrafast turbo-spin echo sequence (UTSE), the eyes were examined within 21 seconds. Sagittal and transversal eye slices were obtained in five passages in five gaze directions (straight ahead, 15 degrees above, 15 degrees below, 15 degrees right and 15 degrees left of the primary position). Displacement of the posterior eye segment was analyzed in relation to the movement of the anterior segment in all directions.

RESULTS

The relationship between the movements of the anterior and posterior eye segment was 1:0.8 (+/- 0.06 SD) during horizontal gaze shifts and 1:1.16 (+/- 0.11 SD) during vertical gaze shifts.

CONCLUSIONS

Magnetic resonance imaging showed that the relationship between anterior and posterior eye segments was different during horizontal and vertical eye movements, indicating the presence of more than one center of rotation. Compared to the anterior eye segment, there was less displacement of the posterior eye segment during horizontal eye movements and more displacement during vertical eye movements.

Treatment of subfoveal choroidal neovascularization associated with multifocal choroiditis and panuveitis with photodynamic therapy

PURPOSE

To study the effects of photodynamic therapy (PDT) using verteporfin on the treatment of patients with subfoveal choroidal neovascularization (CNV) secondary to multifocal choroiditis and panuveitis (MCP), an uncommon disorder with no proven forms of therapy.

METHODS

A retrospective chart review of seven consecutive patients with subfoveal CNV secondary to MCP treated with PDT using verteporfin was performed.

RESULTS

The mean age of the 7 patients (all myopic women) was 41.4 years. A mean of 1.86 treatments was performed, and the mean follow-up time was 10 months. Four of the seven patients were treated unsuccessfully with corticosteroids before referral for PDT. The mean improvement of visual acuity was 0.86 line; 3 patients (42.8%) had an improvement in visual acuity representing at least a halving of their visual angle, while the other 4 patients remained stable. There were no treatment-related side effects.

CONCLUSIONS

Although the follow-up time and the number of patients in this study were limited, the use of PDT was associated with stabilization or improvement of visual acuity in patients with subfoveal CNV secondary to MCP. Further study of this treatment modality is indicated.

Treatment of polypoidal choroidal vasculopathy with photodynamic therapy

PURPOSE

To study the effects of photodynamic therapy using verteporfin in the treatment of patients with subfoveal polypoidal choroidal vasculopathy (PCV).

METHODS

A retrospective chart review of 16 consecutive patients with subfoveal PCV treated with photodynamic therapy using verteporfin was performed.

RESULTS

The mean age of the patients involved was 70.5 years. The mean follow-up time was 12 months. The visual acuity improved in 9 (56.3 %), remained the same in 5 (31.3 %), and decreased in 2 (12.5 %). The mean change in visual acuity was an improvement of 2.38 lines, a difference that was highly significant ( = 0.004). The change in visual acuity was negatively correlated with increasing age. The final visual acuity was positively correlated with initial acuity and negatively correlated with age. These results were confirmed by multiple linear regression. No patient had any lasting complication from the treatment.

CONCLUSIONS

Subfoveal PCV has no proven method of treatment. Although the follow-up time and the number of patients in this pilot study were limited, the encouraging results and lack of complications suggest that further study is indicated.

Treatment of idiopathic subfoveal choroidal neovascular lesions using photodynamic therapy with verteporfin

PURPOSE

To report the effects of photodynamic therapy using verteporfin in the treatment of patients with subfoveal idiopathic choroidal vascularization (CNV).

DESIGN

Interventional case series.

METHODS

In a retrospective study, eight eyes of eight consecutive patients aged 55 years or younger with subfoveal idiopathic CNV treated with photodynamic therapy using verteporfin were evaluated. Visual acuity was considered to be improved if the visual angle was halved, while acuity was thought to be worse if the visual angle doubled.

RESULTS

The eight patients included three men and five women with a mean (+/- SD) age of 34.6 (+/- 9.7) years (range 25-53 years). The mean follow-up time was 13.5 months. At the end of the follow-up period the visual acuity improved in five eyes (62.5%), remained unchanged in one (12.5%), and decreased in two (25%). The mean acuity improvement was 3.6 lines of Snellen acuity by the end of the follow-up period, a change that was statistically significant (P =.027, Wilcoxon signed-rank test). No patient had any complication from the treatment.

CONCLUSIONS

There is no widely accepted method for treating subfoveal idiopathic CNV and all previously investigated methods have had a significant number of serious side effects. Although the follow-up time and the number of patients in this pilot study were limited, the encouraging results and lack of complications suggest that further study is indicated.

Age-related macular degeneration: epidemiology and optimal treatment

Age-related macular degeneration (AMD) is a common macular disease affecting elderly people in the Western world. It is characterised by the appearance of drusen in the macula, accompanied by choroidal neovascularisation (CNV) or geographic atrophy. The disease is more common in Caucasian individuals than in pigmented races. In predominantly Caucasian populations, the age-standardised prevalence of AMD in at least one eye is 7760 cases per million. The age-standardised cumulated 1-year incidence of AMD in at least one eye is 1051 cases per million individuals. AMD is the most important single cause of blindness among Caucasian individuals in developed countries. Blindness resulting from AMD rarely occurs before age 70, and most cases occur after age 80. The age-standardised 1-year incidence of legal blindness resulting from AMD is 212 cases per million. Two-thirds of AMD cases have CNV (exudative cases); the remainder has only geographic atrophy. In cross-sectional population-based studies about 45% of eyes with AMD have visual acuity reduced to 20/200 or worse. This is true both for exudative AMD and pure geographic atrophy. Age and genetic predisposition are known risk factors for AMD. Smoking is probably also a risk factor. Preventive strategies using macular laser photocoagulation are under investigation, but their efficacy in preventing visual loss is as yet unproven. There is no treatment with proven efficacy for geographic atrophy. Optimal treatment for exudative AMD requires a fluorescein angiographic study and a physician capable of interpreting it. For CNV not involving the foveal centre, the only evidence-based treatment is laser photocoagulation. For AMD cases with subfoveal CNV, good visual acuity, and predominantly classic fluorescence pattern on fluorescein angiography, photodynamic therapy with verteporfin is the treatment of choice. Photodynamic therapy is also effective in eyes with pure occult CNV and evidence of recent disease progression. For new subfoveal CNV with poor vision and recurrent CNV, laser photocoagulation can be considered.

Strabological results in patients with macular translocation surgery and counterrotation of the globe as a secondary procedure

INTRODUCTION

Age-related macular degeneration is the most common cause of irreversible loss of visual acuity, including the ability to read, in elderly patients. One of the surgical treatment options is macular translocation with 360 degrees retinotomy. The orthoptic results of torsional muscle surgery as a second procedure are demonstrated.

MATERIALS AND METHODS

Between January 1999 and December 2000, the macula was rotated upward by 12-45 degrees in 10 eyes following complete artificial detachment and a 360 degrees retinotomy. In these patients, torsional surgery was carried out as a second procedure. Depending on the resulting cyclotorsion, we performed surgery on the oblique muscles only in four patients with a cyclotropia of 12-20 degrees and a combination of oblique muscle surgery with surgery of two or four rectus muscles in the remaining six eyes (cyclotropia over 21 degrees ). The pre- and postoperative diagnostic techniques included visual acuity, reading vision and the orthoptic status.

RESULTS

Due to the unilateral ectopia of the macula, all patients presented postoperative strabismus with a vertical deviation of 2-10 degrees and a subjective cyclotropia between 12 degrees and 40 degrees. After surgery on the oblique muscles, the patients showed a residual cyclotropia of 0-6 degrees. In patients in whom surgery on the oblique muscles was accompanied by rectus muscle surgery, the remaining cyclotorsion was 5-13 degrees. Four patients excluded the non-operated fellow eye, six patients experienced double vision under binocular conditions and thus required prescription of additional prism glasses.

CONCLUSION

Macular translocation causes diplopia under binocular conditions because of the unilateral ectopia of the macular region with cyclotropia and vertical deviation. These problems can be resolved or reduced by oblique muscle surgery or in combination with additional surgery on the rectus muscles, depending on the range of the cyclotorsion. Performing the torsional surgery as a second procedure after macular rotation with an exact preoperative measurement of the subjective cyclodeviation appears to be useful.

Radiotherapy for age-related macular degeneration: is there a benefit for classic CNV?

AIM

To evaluate the efficacy of radiotherapy in the treatment of subfoveal classic and occult choroidal neovascularization (CNV) in age-related macular degeneration (AMD) under strict fixation control.

METHODS

Twenty-seven eyes of 27 patients with subfoveal CNV as a result of AMD were treated with a total dose of 20 Gy in 10 fractions (10 well-defined, 17 occult). Fixation monitoring was achieved by installing a TV camera with an attached fixation light 3 cm from the cornea of the eye being treated. Visual acuity and fluorescein angiography were obtained before and 6 months after treatment. Fifteen eyes of 15 patients served as controls (4 well-defined, 11 occult).

RESULTS

After 6 months the treated group showed an average decrease in visual acuity of 27%; the control group experienced a decrease of 31%. Membrane size increased by 56% in the treated group and by 28% in the control group. There was no statistically significant difference. Within the subgroup analysis, however, patients with classic CNV suffered significantly less visual loss than in the control group.

CONCLUSION

Radiation therapy under optimized treatment conditions by fixation monitoring failed to control further growth in membrane size in both classic and occult CNV. Regarding visual acuity, however, patients with classic CNV seem to benefit from radiation treatment compared to the natural course.

Recent advances in the management of age-related macular degeneration

Choroidal neovascularization (CNV) secondary to age-related macular degeneration (AMD) can cause rapid and severe central vision loss in many older people. Until recently, the only treatment proven beneficial was thermal laser photocoagulation, which was applicable to only a small subset of patients. Furthermore, the thermal laser damaged the retina overlying the CNV, which is especially problematic for lesions involving the foveal center. Photodynamic therapy is a new treatment consisting of intravenous infusion of a drug that is then activated by a low-energy laser, causing damage to CNV. Photodynamic therapy with verteporfin (Visudyne, Novartis AG) has been shown to reduce the risk of moderate and severe vision loss in patients with predominantly classic subfoveal CNV secondary to AMD. With the advent of verteporfin therapy, eye care providers will play an increasingly important role in managing patients with AMD, especially in the early detection and rapid referral of appropriate cases.

Radiotherapy in age-related macula degeneration

PURPOSE

To ascertain the benefit from radiotherapy in age-related macula degeneration in a single-arm longitudinal study.

METHODS AND MATERIALS

From 1997 to 1998, 39 patients with occult and 33 patients with classic choroidal neovascularization (CNV) were irradiated with 16 Gy. Fluorescein angiography and measurements of visual acuity were performed before and 3, 6, and 12 months after irradiation.

RESULTS

Complete follow-up data for 1 year were available from 69 patients. The mean patient age was 72 years (range 49-92). Vision decreased in 43, was stable in 18, and improved in 8 cases. The mean vision deteriorated significantly (p = 0.02, Wilcoxon test), particularly within the first 3 months. Patients with occult CNV did significantly better than did those with classic CNV (p = 0.03). The proportion of patients retaining vision > or = 0.2 fell from 65% to 42% (p <0.01), for classic and occult CNV from 50% to 23%, and for occult CNV from 77% to 56% (p < 0.02), respectively. CNV size increased in 30 patients and was stable in 38. Neither age (p = 0.17) nor gender (p = 0.21, chi-square test) influenced prognosis. Four patients reported transitional complaints.

CONCLUSION

Low-dose fractionated radiotherapy with 16 Gy is well tolerated. However, vision and reading ability were not preserved in most patients.

Diplopia after limited macular translocation surgery

PURPOSE

Full macular translocation surgery relocates the fovea away from choroidal neovascularization, inducing significant postoperative torsional diplopia. In "limited macular translocation," a saline-induced retinal detachment is followed by scleral imbrication with mattress sutures and spontaneous retinal reattachment. In this study, diplopia was characterized in patients treated with limited macular translocation.

METHODS

Two surgeons performed retinal translocation surgery on 250 patients over an 18-month time span. The extent and direction of the retinal translocation, and the amount and location of scleral imbrication, were recorded. All patients complaining of diplopia were referred for ocular motility evaluation and treatment.

RESULTS

Thirteen (5.2%) patients complained of occasional or constant diplopia. Imbricating sutures were placed supero-temporally in all cases. Inferior foveal translocation ranged from 200 to 2115 microm (median, 1750 microm). Visual acuity ranged from 20/40 to 20/400 in the operated eye. Prism-and-cover testing underestimated the strabismus when compared with subjective testing. In 3 patients, there was no shift on alternate-cover testing despite binocular diplopia. Excyclotorsion ranged from 0 degrees to 16 degrees. Diplopia resolved in 10 cases with prism; 3 required an occlusive filter for distortion or aniseikonia. One patient underwent successful strabismus surgery to eliminate dependence on prism glasses.

CONCLUSIONS

Limited macular translocation only rarely produces symptomatic diplopia. Suprisingly, traditional prism-and-cover testing does not reliably quantify the misalignment. This may result from the combination of a persistent macular scotoma and a repositioned fovea relative to the peripheral retina. Prism therapy is generally satisfactory in the absence of retinal distortion or aniseikonia.

A 5-year follow-up study for distance visual acuity after low dose radiation on subfoveal choroidal neovascularization in age-related macular degeneration

In a prospective study with a 5-year follow-up, we assessed the effect of a single series of low-dose radiation on the distance visual acuity in eyes with angiographically confirmed subfoveal choroidal neovascularization (CNV) in age-related macular degeneration (ARMD). The posterior pole of 12 eyes was treated with 5 Gy (4 x 1.25 Gy), and 34 eyes treated with 8 Gy (4 x 2 Gy). The best corrected distance visual acuity was measured at the time of treatment, and annually thereafter for 5 years. The study obtained complete follow-up for 11 patients in the 5-Gy group (nine classic, two occult CNVs), and 29 patients in the 8-Gy group (12 classic, 17 occult CNVs). At baseline, the mean distance visual acuity of the treated eyes was 0.16 (20/125) in the 5-Gy group, and 0.2 (20/100) in the 8-Gy group. Five years later, an average loss of 3.2 lines was present in the 5-Gy group, and 4 lines in the 8-Gy group. After 5 years, an average loss of 2 lines was found in a control group consisting of 18 second eyes with low stage dry ARMD, with a mean distance visual acuity of 0.5 (20/40) at baseline. Statistical analyses with Wilcoxon and Mann-Whitney U-tests showed that a single series of low dose radiation with either 5 Gy or 8 Gy was not able to stabilize the distance visual acuity of eyes with subfoveal CNV in ARMD during a 5-year follow-up.

Drug targeting to choroidal neovascularization

Subfoveal choroidal neovascularization (CNV) causes significant visual loss, especially in patients with age-related macular degeneration (AMD). Several pharmaceutical treatments that use anti-angiogenic agents have been tried to inhibit the activity of CNV experimentally and clinically. In general, however, systemically administered drugs may reach not only targeted tissues but also other tissues, resulting in unwanted side effects. Also, to maintain therapeutic levels of the drugs in targeted tissues, frequent administration for an extended period of time is required. To solve these problems, drug delivery systems targeted to the CNV are being developed. Anatomic characteristics of CNV tissues resemble those of tumor vasculature, exhibiting enhanced permeability and retention effect. Drug targeting to CNV may be feasible in the same manner as it is to tumors. In this review, we describe two approaches of drug targeting to CNV: passive targeting and active targeting.

Retinal pigment epithelial cell transplantation after subfoveal membranectomy in age-related macular degeneration: clinicopathologic correlation

PURPOSE

To report the histopathology after retinal pigment epithelial cell transplantation and subfoveal membranectomy in age-related macular degeneration.

METHODS

An 85-year-old white woman with bilateral choroidal neovascularization underwent subfoveal membranectomy combined with transplantation of a sheet of human adult retinal pigment epithelium (retinal pigment epithelium) under the foveal center in the right eye. The patient was immunosuppressed postoperatively with prednisone, cyclosporine, and azathioprine. The patient died from congestive heart failure 114 days after surgery.

RESULTS

A patch of hyperpigmentation was visible at the transplant site under the foveola after surgery. Mound-like clusters of individual round, large densely pigmented cells were present in the subretinal space and outer retina in this area. There was loss of the photoreceptor outer segments and native retinal pigment epithelium in the center of the transplant bed, with disruption of the outer nuclear layer predominantly over regions of multilayered pigmented cells. Cystic spaces were present in the inner and outer retina. A residual intra-Bruchs membrane component of the original choroidal neovascular complex was present under the transplant site.

CONCLUSIONS

The transplant site contained clusters of round, pigmented cells that did not form a uniform monolayer in most areas. The morphology at the transplant site is consistent with the lack of visual improvement seen after surgery in this patient.

Translocation of the macula for management of subfoveal choroidal neovascularization: comparison of results in age-related macular degeneration and degenerative myopia

PURPOSE

To report the results of limited macular translocation in subfoveal choroidal neovascularization resulting from age-related macular degeneration or degenerative myopia.

METHODS

The first consecutive 32 patients (23 age-related macular degeneration eyes and nine myopic eyes) were operated on with the limited macular translocation technique described by de Juan. Before and after surgery, a complete examination included fluorescein and indocyanine-green angiographies and optical coherence tomography. Mean follow-up was 9 months in the age-related macular degeneration group (range, 6 to 14 months) and 10 months in the myopic group (range, 6 to 15 months).

RESULTS

The improvement in visual acuity was better in the myopic group than in the age-related macular degeneration group and was correlated with younger age in the myopic group (P <.05). At the end of follow-up, visual acuity improved by 2 lines or more in seven age-related macular degeneration eyes (30%), including four eyes (13%) with an improvement of 6 lines or more, and in six myopic eyes (67%), including two eyes (22%) with an improvement of 6 lines or more. Final visual acuity was unchanged in four age-related macular degeneration eyes (17%) and three myopic eyes (33%), and decreased in 12 age-related macular degeneration eyes (52%). Conversely, the mean foveal displacement was greater in age-related macular degeneration than in myopia (1,105 microm and 685 microm, respectively; P <.05). Main complications were retinal detachment (six eyes), neovascularization at the injection site (two eyes), and recurrence of neovascularization (43% of the age-related macular degeneration group and 11% of the myopic group).

CONCLUSIONS

Limited macular translocation allowed a significant improvement in visual acuity in some eyes with subfoveal neovascularization and resulted in a moderate rate of complications. Longer follow-up and additional studies are required to confirm these findings.

Gamma knife treatment of subfoveal, classic neovascularization in age-related macular degeneration: a pilot study

Object. Age-related macular degeneration (AMD) is the leading cause of severe vision loss in people older than age 65 years in the western world. The visual acuity loss usually results from the ingrowth of new vessels from the choroid capillaries, so called choroidal neovascularization (CNV). The aim of this pilot study was to investigate the effect of a single-fraction gamma knife radiosurgery (GKS) on visual acuity and the growth pattern of CNV in patients with AMD.

Methods. Ten patients with a mean age of 75 years and with a subfoveal, classic CNV due to AMD were enrolled in this study. All patients were treated with GKS in one fraction with a prescription dose of 10 Gy. The treatment target was the CNV located in the macula. Computerized tomography scans of the globe were obtained.

After a follow up of 1 year visual acuity was stable in six patients and decreased in four. The size of the CNV could be stabilized in four patients, and in six an enlargement of these neovascular complexes was shown. No side effects, such as cataract formation, development of radiation-induced retinopathy, or optic neuropathy, have been observed so far.

Conclusions. Gamma knife radiosurgery seemed to have a beneficial effect on visual acuity in patients with AMD, but it failed to control growth of CNV in six patients. A longer follow up, a larger study population, and a randomized and controlled study are necessary for a final conclusion.

Age-related macular degeneration: long-term results of radiotherapy for subfoveal neovascular membranes

PURPOSE

To study results of 2-year follow-up of radiotherapy for subfoveal choroidal neovascular membrane associated with age-related macular degeneration.

METHODS

In a randomized prospective clinical study, 101 patients received a low-dose radiotherapy or no treatment. In the treatment group, subfoveal choroidal neovascular membranes were treated with 20 Gy of 6-MV photons to the macula of the affected eye.

RESULTS

The overall complete follow-up rate was 84.2% (85/101). No measurable treatment-related morbidity was seen during or after treatment. Mean changes in log of minimal angle of resolution (logMAR) of visual acuity and area of choroidal neovascular membrane for 2-year follow-up were +0.226 +/- 0.373 and 143.5 +/- 53.1% in the treatment group, and +0.563 +/- 0.370 and 190. 3 +/- 81.4% in the control group; a significant difference was found (P <.0001; P =.0008). In patients with smaller choroidal neovascular membrane (</=1.5 mm(2)) or better visual acuity (>/=60/200) at baseline, the treatment group showed a significantly smaller increase in area of choroidal neovascular membrane and a significantly smaller decrease in LogMAR visual acuity for 2 years, whereas there was no significant difference in patients with larger choroidal neovascular membrane (>1.5 mm(2)) or poorer visual acuity (<60/200).

CONCLUSIONS

Radiotherapy appeared to have a favorable treatment effect in eyes with subfoveal neovascular membrane associated with AMD. Favorable factors for radiotherapy were a smaller area of choroidal neovascular membrane and better visual acuity.

Radiotherapy for subfoveal neovascularisation associated with pathological myopia: a pilot study

BACKGROUND/AIM

Limited treatments are available for this disease process. A pilot study was performed to determine the toxicity and efficacy of external beam radiotherapy for subfoveal neovascular membranes and subretinal haemorrhage associated with pathological myopia.

METHODS

A randomised, prospective study was carried out on 39 patients with subfoveal neovascularisation associated with high myopia. 20 patients underwent radiotherapy and the remaining 19 were observed as a randomised comparison group. All patients were followed up for at least 24 months. Subfoveal choroidal neovascular membranes (CNVMs) were treated with a single lateral 6 MV photon beam to a dose of 10 Gy in five fractions over 5-7 days. Post-treatment measurements included corrected visual acuity, area of CNVM, and occurrence of radiotherapy related complications, and adverse reactions. To assess changes of area of CNVM, the initial (pretreatment) size of the CNVM was set to 100%, and all post-treatment measurements were normalised relative to the initial size.

RESULTS

No significant acute morbidity was noted. There was no significant difference in age, sex, refractive error, visual acuity, and area of CNVM at baseline between the treatment group and control group. The mean change of the size of the CNVM for 2 years was 155% (SD 156%) in the treatment group and 249% (124%) in the control group. The increase in the size of CNVM in the treatment group was significantly smaller than that in the control group (p = 0.0452). In the treated eyes, the visual acuity before and 1 and 2 years after radiotherapy were 0.111 (22.2/200), 0.091 (18.2/200), and 0.086 (19.2/200), respectively. In the control eyes, visual acuity before and 1 and 2 years after the start of the follow up were 0.141 (34.2/200), 0.089 (17.8/200), and 0.063 (12.6/200). The patients in the treatment group showed no significant change for 2 years, and those in the control group showed a significant decrease in the visual acuity (p = 0.0033). The changes of logMAR of visual acuity for 2 years after the start of the follow up were +0.019 (0. 443) in the treatment group and +0.347 (0.374) in the control group. There was a statistically significant difference between them (p = 0. 0173). Multiple regression analysis on the treatment group showed that the most significant predictive variable for the visual acuity 2 years after the treatment was the combination of pretreatment visual acuity and refractive error.

CONCLUSIONS

Radiotherapy appeared to have a favourable treatment effect in eyes with subfoveal neovascular membranes and haemorrhage associated with pathological myopia. Further investigation is needed to evaluate the efficacy of radiotherapy for subfoveal neovascularisation associated with pathological myopia.