Clinicopathologic studies of age-related macular degeneration with classic subfoveal choroidal neovascularization treated with photodynamic therapy

Choroidal Neovascular Membranes after Photodynamic Therapy: Ultrastructural Analysis of Two Surgically Excised Membranes

PURPOSE

To report on the ultrastructural electron microscopic findings of two surgically excised subfoveal choroidal neovascular membranes (CNV) that had undergone photodynamic therapy (PDT).

METHODS

Two patients underwent PDT because of subfoveal neovascular membranes (CNV). Due to enlargement of the CNV seen on fluorescein angiography three months after PDT, one patient underwent surgical excision of the membrane; the other patient underwent both surgical membrane excision combined with macular translocation one month after PDT. The membranes were examined under the transmission electron microscope (TEM).

RESULTS

The membranes were composed of a core and a rim, the latter being mainly composed of fibrin and collagen fibrils. The core was preeminently composed of endothelium-lined vascular channels associated with retinal epithelium cells. The endothelial cells of blood vessels appeared well-preserved.

CONCLUSIONS

The lack of histological signs of recanalization and vascular thrombosis may indicate that in our cases the enlargement of the CNVs seen on fluorescein angiography three months and one month respectively after PDT may originate mainly from reproliferation of choroidal vessels rather than recanalization of previously occluded vessels.

Combination treatment of photodynamic therapy with verteporfin and intravitreal ranibizumab in patients with retinal angiomatous proliferation

PURPOSE

To investigate the efficacy and safety of initial photodynamic therapy (PDT) with a ranibizumab loading dose of three monthly intravitreal injections and a subsequent PRN ranibizumab regimen in the treatment of retinal angiomatous proliferation (RAP).

METHODS

In this 12-month prospective case series, 15 patients underwent PDT followed by 3 intravitreal ranibizumab injections at monthly intervals. At monthly follow-up examinations, further single ranibizumab injections were given in case of any intra- or subretinal fluid on optical coherence tomography (OCT), visual loss ≥5 letters or signs of activity on fluorescein or indocyanine green angiography.

RESULTS

Best-corrected visual acuity (BCVA) improved from 58.1 ± 13.2 at baseline by 9.2 letters (SD ± 8.5; p = 0.004) at 6 months and by 8.7 letters (SD ± 11.4; p = 0.017) at 12 months. Neither at 6 nor at 12 months, any patient had lost ≥15 letters. The mean number of injections per patient was 4.8 (SD ± 1.4) in the first year of therapy after PDT. The average time to first retreatment was 3.7 months (range 1-7 months). No serious adverse events, such as endophthalmitis or retinal detachment, were noted.

CONCLUSION

PDT with 3 ranibizumab loading injections and subsequent ranibizumab as needed resulted in a significant gain of 8.7 ± 11.4 letters at month 12. This regimen is safe and efficacious, but even in a population of mostly early stages of RAP, retreatment rates remained high.

Neovascular age-related macular degeneration: opportunities for development of first-in-class biopharmaceuticals

Age-related macular degeneration (AMD) is a condition that may cause blindness. The prevalence of the disease in the Western world is estimated at 1-2% of the population. Over the past decade, treatment of neovascular AMD has been shifting from destruction of newly formed blood vessels towards inhibitors that silence the vascular endothelial growth factor (VEGF) pathway. Such agents are often first-in-class biopharmaceuticals that benefit from the fact that they can be locally administered in an immune-privileged environment with slow clearance. These new VEGF pathway inhibitors have improved therapeutic effects over conventional treatment and have promoted the identification of novel targets for inhibition of AMD angiogenesis. This review describes the rationale behind the shift from conventional to current treatment options and discusses investigational, most notably biopharmaceutical, drugs that are in clinical trials. It also provides possible points for improvement of these treatments, specifically regarding their delivery.

Improvement of attention span and reaction time with hyperbaric oxygen treatment in patients with toxic injury due to mold exposure

It is, by now, well established that mold toxins (mycotoxins) can cause significant adverse health effects. In this study, 15 subjects who developed an attention deficit disorder (ADD) and slowing of reaction time at the time of exposure to mold toxins were identified. Deficits in attention span and reaction time were documented not only by taking a careful history, but also by performing a Test of Variables of Attention (TOVA). The TOVA test provides an objective measure of these two variables. It was found that mold-exposed subjects show statistically significant decreases in attention span and significant increases in reaction time to stimuli compared to controls. After ten sessions of hyperbaric oxygen treatment (HBOT), a statistically significant improvement was seen in both measures. This preliminary study suggests promising outcomes in treating mold-exposed patients with hyperbaric oxygen.

Changes in visual function and thickness of macula after photodynamic therapy for age-related macular degeneration

PURPOSE

To determine the correlation between the changes in the central retinal sensitivity and the changes in the foveal thickness (FT) after photodynamic therapy (PDT) for age-related macular degeneration (AMD).

METHODS

Nineteen eyes of 19 patients with choroidal neovasularizations (CNVs) secondary to AMD were studied. The pretreatment values of the central retinal sensitivity determined by Micro Perimeter 1 (MP1; Nidek Technologies), best-corrected visual acuity (BCVA), and optical coherence tomography (OCT)-determined FT were compared to the postoperative values at three and six months after PDT.

RESULTS

At six months, the retinal sensitivity within the central 10 degrees was significantly improved (P = 0.02) and the FT was significantly thinner (P = 0.016). The BCVA, however, did not change significantly (P = 0.80). The changes in the retinal sensitivities were significantly correlated with the changes in the decrease in the FT (r = - 0.59, P = 0.012 within the central 10 degrees ) at six months after PDT.

CONCLUSION

Significant improvements in retinal sensitivities within the central 10 degrees and a decrease in FT were observed even though the BCVA was not significantly improved. The measurement of retinal sensitivity by MP1 may be a better method to assess central visual function than the conventional visual acuity after PDT.

The role of vascular endothelial growth factor and other endogenous interplayers in age-related macular degeneration

Age-related macular degeneration (AMD) is a multifaceted disease characterized by early subclinical changes at the choroidea-retinal pigment epithelium interface. Both the causal and formal pathogenesis of the disease is still puzzling. Similarly, the reason for progression into two distinct late forms which are "geographic atrophy" and "choroidal neovascularization" remains enigmatic. Late changes are usually responsible for the dramatic loss in central function that has a devastating effect on quality of life. In industrialized countries the disease is a major cause for visual disability among persons over 60 years of age. Due to demographic right-shift and increased life expectancy, AMD is not only a medical problem but will have a pronounced socio-economic effect. Neovascular AMD with the development of choroidal neovascularization in the macular area accounts for 80% of the severe loss of visual acuity due to AMD. In the last decades, treatment modes were merely based on the destruction or surgical removal of the neovascular complex. In the present, however, the philosophical approach to treat the disease is changing to a pathology modifying manner. Intelligent targeting of the involved relevant factors and pathways should stop disease progression, reduce complications and improve vision. The first step into this new era has been accomplished with the introduction of antiangiogenic agents. The new agents act either directly on vascular endothelial growth factor (VEGF) or indirectly on its functional cascade. VEGF makes a fundamental contribution to neovascular processes but it also acts in physiological pathways. The main purpose of this review is to summarize its physiological role especially within the eye, the role in the development of AMD and to understand and foresee both the benefits and potential side-effects of the anti-VEGF-based therapy.

INFLUENCE OF VERTEPORFIN PHOTODYNAMIC THERAPY ON INFLAMMATION IN HUMAN CHOROIDAL NEOVASCULAR MEMBRANES SECONDARY TO AGE-RELATED MACULAR DEGENERATION

PURPOSE

To examine the short- and long-term consequences of verteporfin photodynamic therapy (PDT) on inflammation with regard to infiltration of macrophages and leukocytes and expression of thy-1 in human choroidal neovascularization membranes (CNV) secondary to age-related macular degeneration (AMD).

METHODS

Retrospective review of an interventional case series of 43 patients who underwent removal of CNV. Twenty patients were treated with PDT 3 to 246 days preoperatively. Twenty-three CNV without previous treatment were used as control. CNV were stained for CD34, CD105, cytokeratin 18, Ki-67, thy-1, an endothelial cell glycoprotein known to be upregulated only by inflammatory cytokines, CD68 (macrophages), and CD45 (common leukocyte antigen).

RESULTS

Specimens treated by PDT 3 days previously showed significantly reduced endothelial thy-1 expression (P = 0.008), leukocyte (P=0.04) and macrophage (P=0.0063) infiltration, and proliferative activity (P=0.02) compared to control CNV. Specimens at longer intervals after PDT, in contrast, disclosed a significantly increased expression of thy-1 (P=0.004), infiltration with leukocytes (P=0.044) and macrophages (P=0.01), and proliferative activity (P=0.03) compared to CNV excised 3 days after PDT.

CONCLUSIONS

The rebound effect after PDT seems to be based on an inflammatory response that contributes to enhanced proliferation. These data support the need for an anti-inflammatory therapy as adjuvant to PDT.

Histopathological findings in postmortem eyes after photodynamic therapy for choroidal neovascularisation in age-related macular degeneration: report of two cases

BACKGROUND

To report the histopathological findings after photodynamic therapy (PDT) in eyes obtained postmortem with choroidal neovascularisation (CNV) secondary to age-related macular degeneration (AMD).

METHODS

Two eyes were obtained postmortem from two patients with CNV secondary to AMD. Both of the patients had been treated with PDT. Serial sections through the posterior poles were obtained and stained with haematoxylin-eosin, periodic acid-Schiff, Masson trichrome or phosphotungstic acid haematoxylin (PTAH). Two-dimensional reconstructions were prepared and compared with fluorescein angiograms.

RESULTS

The interval between PDT and death was 3 months and 17 months in each patient, respectively. Light-microscopic examination showed that CNV enveloped with retinal pigment epithelium (RPE) in both eyes. The average size of the CNV was 550 x 280 microm. One eye had combined (subRPE/subretinal) growth pattern CNV, and the other eye had both type I (subRPE) and combined growth pattern CNV. All specimens contained fibrous proliferation and patent vascular channels within the CNV, and there was no thrombus formation within the vascular channels. No apparent abnormalities in the choroid were observed by light microscopy.

CONCLUSIONS

Although involution with fibrous tissue proliferation occurred, PDT did not result in permanent occlusion of the vascular channels in the CNV. Our findings indicate that PDT may accelerate involution of CNV, thus limiting its size and preserving photoreceptors.

Complete blood vessel occlusion in the chick chorioallantoic membrane using two-photon excitation photodynamic therapy: implications for treatment of wet age-related macular degeneration

Complete blood vessel occlusion is required for the treatment of age-related macular degeneration (AMD). AMD is the leading cause of blindness in developed countries and current treatment regimes have potential to cause collateral damage, or do not remove pre-existing unwanted vasculature. It has been proposed that two-photon excitation (TPE) photodynamic therapy (PDT) can be applied to cause local blood vessel occlusion without damaging surrounding retinal tissues. The in ovo chicken chorioallantoic membrane (CAM) is used as the model for vascularization in the wet form of AMD; novel techniques for the utilization of the CAM are reported. Complete occlusion of CAM vessels approximately 15 microm in diameter is achieved using the clinically approved photosensitizer Verteporfin (Visudyne, QLT, Incorporated, Vancouver, British Columbia, Canada) and TPE activation. The average and peak irradiances used for treatment are 3.3x10(6) Wcm(2) and 3.7x10(11) Wcm(2), respectively. A total fluence of 1.1x10(8) Jcm(2) is the dosage required for successful occlusion, and it is expected that for optimal conditions it will be much less. These results are the first proof-of-principle evidence in the literature that indicate TPE-PDT can be used to occlude small blood vessels. Further investigation will help determine the utility of TPE-PDT for treating wet AMD, perhaps through targeting feeder vessels.

Intravitreal bevacizumab (Avastin) in combination with verteporfin photodynamic therapy for choroidal neovascularization associated with age-related macular degeneration (IBeVe Study)

BACKGROUND

A novel alternative for combined treatment using verteporfin photodynamic therapy (PDT) has emerged as preliminary safety and efficacy data of the intravitreal use of the anti-angiogenic bevacizumab became available. In the current study we investigate the feasibility of intravitreal bevacizumab combined with verteporfin PDT for the treatment of choroidal neovascularization (CNV) secondary to age-related macular degeneration (AMD).

METHODS

A single-centre, prospective, open-label study of 11 patients with documented CNV progression after PDT treatment who underwent combined PDT and intravitreal injection of 1.5 mg of bevacizumab was undertaken. Standardized ophthalmic evaluation was performed at baseline and at weeks 1, 2, 12 and 24. Clinical evidence of complications and changes in logarithm of the minimum angle of resolution (logMAR) best-corrected visual acuity (BCVA) using Early Treatment Diabetic Retinopathy Study (ETDRS) charts and in fluorescein leakage from CNV were evaluated.

RESULTS

The mean (+/-SD) age of the 11 patients was 74 (+/-5) years. Seven eyes had been treated with one previous PDT session and four eyes had two previous PDT sessions. The mean baseline logMAR ETDRS BCVA was 1.031 (Snellen equivalent, 20/200(-2)). At follow-up weeks 1, 2, 12 and 24, the mean logMAR ETDRS BCVA (Snellen equivalent) was 0.944 (20/160(-2)), 0.924 (20/160(-1)), 0.882 (20/160(+1)), and 0.933 (20/160(-2)), respectively. The change in BCVA from baseline was significant at each study follow-up interval (P < or = 0.001); at 12 and 24 weeks, the mean change in BCVA from baseline was an improvement of 1.49 and of 0.98 ETDRS line, respectively. Fluorescein leakage from CNV was absent in all eyes at week 12. One additional treatment session was required in seven (63.6%) eyes at week 24 due to recurrent fluorescein leakage from CNV ("minimum" [<50% of the leaking area noted at baseline], n = 4; and "moderate" [>50% of the leaking area noted at baseline], n = 3). No progression of the neovascular lesion was observed at week 24. No safety issues were identified throughout the period of the study.

CONCLUSIONS

The overall changes in vision and fluorescein leakage from CNV throughout the study suggest that a possible synergistic effect may arise from the combination of intravitreal bevacizumab with verteporfin PDT for the treatment of neovascular AMD.

Optical coherence tomography analysis of bilateral end-stage choroidal neovascularization where one eye is treated with photodynamic therapy

BACKGROUND

To compare retinal thickness and subretinal hyper-reflectivity using Stratus optical coherence tomography (OCT3) between the eyes of patients with bilateral end-stage exudative age-related macular degeneration (AMD), where one eye has been treated with photodynamic therapy (PDT).

METHODS

Patients with PDT-treated stable choroidal neovascularization (CNV), defined as a fibrotic lesion not requiring treatment for 6 months, in one eye and an untreated end-stage CNV (disciform) scar in their fellow eye, underwent refraction protocol logMAR visual acuity (VA) in letters, slit-lamp biomicroscopy, fluorescein angiography and OCT3 scan. Subretinal scar thickness was measured as Outer High Reflectivity Band Thickness (OHRBT) and retinal thickness as neuroretinal foveal thickness (NFT) on OCT3.

RESULTS

Thirty-two eyes of 16 patients were studied. Mean OHRBT was 255.62 microm in treated eyes and 350.8 microm in untreated eyes (P = 0.001). Mean NFT was 130.3 microm in the treated eye and 79.9 microm in the untreated eye (P = 0.017). Mean VA was 42 letters in treated eyes and 15 letters in untreated eyes (P < 0.005).

CONCLUSION

Based on OCT3 findings, eyes with AMD treated with PDT have a thinner fibrous scar and better preserved retinal thickness when compared with untreated fellow eyes with end-stage fibrotic scarring.

Retinal pigment epithelium changes after photodynamic therapy for choroidal neovascularization in pathological myopia

PURPOSE

To describe changes in the retinal pigment epithelium (RPE) induced by photodynamic therapy (PDT) in eyes with subfoveal choroidal neovascularization (CNV) associated with pathological myopia (PM).

METHODS

We carried out an open-label, prospective, interventional case series including 26 patients affected by subfoveal CNV in PM who underwent PDT with a 12-month follow-up. Particular attention was paid to the detection of changes at the RPE level in the areas exposed to the laser compared with baseline conditions.

RESULTS

The median age of the patients was 58.5 years and the median duration of symptoms was 2 weeks. A pigmentary zone was present before PDT in 20 eyes (77%), incompletely encircling the CNV in all but two of the 20 eyes. At the end of the follow-up, the CNV in all eyes was seen to be completely or incompletely encircled by a band of hyperpigmentation, which was surrounded by RPE alterations, including depigmentation in all cases and atrophic changes in 14 eyes.

CONCLUSIONS

After PDT, alterations in the RPE develop in myopic eyes. These include accentuation of the pigmentary zone surrounding the CNV and progressive atrophic changes. Further studies are needed to correlate post-PDT RPE damage with longterm visual outcome.

Verteporfin photodynamic therapy induced apoptosis in choroidal neovascular membranes

AIM

To evaluate the impact of verteporfin photodynamic therapy (PDT) on the induction of apoptosis in choroidal neovascular membranes (CNV) secondary to age related macular degeneration.

METHODS

Retrospective review of 22 surgically excised CNV. 12 of these patients had been treated with PDT 3-146 days previously. Apoptotic cells were detected with the TUNEL technique and compared to the expression of CD34 (endothelial cells, EC), CD105 (activated endothelial cells), Ki-67 (proliferation marker), and cytokeratin18 (retinal pigment epithelial cells, RPE).

RESULTS

CNV excised 3 days after PDT were characterised both by collapsed and patent vessels. The EC displayed a statistical significant positive TUNEL reaction when compared to the remaining treated CNV (p < 0.001) and untreated CNV (P = 0.002). The proliferative activity was reduced. CNV excised 1-5 months after PDT displayed a patent vascularisation and high proliferative activity. All membranes either treated or untreated disclosed only sporadic TUNEL positive cells within the stroma and the RPE.

CONCLUSIONS

Verteporfin PDT leads to selective and effective damage of EC within CNV. Both patent and occluded vessels were lined by apoptotic EC. This finding and the increased expression of proliferation marker at later time points suggest that revascularisation after PDT is caused by angiogenesis rather than recanalisation.

Photodynamic therapy with verteporfin for retinal angiomatous proliferation

PURPOSE

The aim of this study was to evaluate the results of photodynamic therapy (PDT), using verteporfin, for subfoveal neovascular age-related macular degeneration (ARMD) with retinal angiomatous proliferation (RAP) with pigment epithelial detachment (PED) and/or choroidal neovascularization (CNV).

METHODS

In this non-comparative, consecutive, interventional, case series, the data on 21 eyes (19 with stage 2 and two with stage 3 RAP) of 20 patients were reviewed. Serous PED occupied more than 50% of the lesion in 19 eyes. PDT was performed as per TAP protocol. Biomicroscopy and fluorescein and indocyanine-green angiography were performed to evaluate anatomical results and need for retreatment. Changes from baseline in best-corrected visual acuity (BCVA), and complications, were assessed.

RESULTS

A mean of 3.5+/-0.9 treatments was performed. After 13.7+/-2.2 months, mean BCVA decreased from 20/80 to 20/174 (P=0.0063). In six eyes (28.6%) BCVA remained stable, whereas in 15 eyes (71.5%) it decreased. Occlusion of RAP and flattening of PED was observed in three (14.2%) eyes, conversion to disciform lesion in one (4.7%), and persistence of PED in 11 eyes (52.3%). One eye (4.7%) evolved to haemorrhagic PED, and one (4.7%) toward stage 3 RAP. A tear in the retinal pigment epithelium (RPE) was observed in four eyes (19%). Eleven (52.3%) showed progression of leakage, six moderate leakage (28.6%), and three (14.2%) absence of leakage.

CONCLUSIONS

Timely PDT with verteporfin in the early stages in eyes with smaller lesions has the potential for a beneficial effect on vision, whereas it might worsen the natural course of larger lesions, with most eyes undergoing enlargement, disciform transformation or RPE tear.

Combined Photodynamic Therapy and Intravitreal Triamcinolone Acetonide Injection for Neovascular Age-Related Macular Degeneration With Pigment Epithelium Detachment

BACKGROUND AND OBJECTIVE

To report the outcome of combined verteporfin photodynamic therapy (PDT) and intravitreal triamcinolone acetonide (IVTA) for the treatment of choroidal neovascularization (CNV) with serous pigment epithelium detachment (PED) due to age-related macular degeneration (AMD).

PATIENTS AND METHODS

The files of all consecutive patients with CNV and serous PED who received PDT and IVTA either primarily (primary treatment group) or following previous unsuccessful PDT (secondary treatment group) were reviewed for visual and angiographic results.

RESULTS

Ten patients (11 eyes) were included. Mean number of PDT sessions was 3.18; 8 eyes received one IVTA injection and 3 eyes received two IVTA injections. Thirty-six percent of patients retained their initial visual acuity after a mean follow-up of 15.3 months. Loss of 3 or more Snellen lines was noted in 2 of 3 eyes in the primary treatment group and 5 of 8 eyes in the secondary treatment group. Increased intraocular pressure developed in 3 patients and was controlled by topical medications.

CONCLUSIONS

Although combined PDT and IVTA may be considered for CNV with serous PED in patients with poor prognosis with PDT alone, the regimen as administered in this small series was not beneficial. Further studies are required to determine whether alternate sequences, timing, or doses would yield a better outcome.

Indocyanine green-mediated photothrombosis with and without intravitreal triamcinolone acetonide for subfoveal choroidal neovascularization in age-related macular degeneration: a pilot study

PURPOSE

To determine the feasibility, safety, and clinical effect of treating patients with subfoveal choroidal neovascularization (CNV) in age-related macular degeneration (AMD) with indocyanine green (ICG)-mediated photothrombosis (IMP) with and without intravitreal triamcinolone acetonide (TA).

METHODS

Fifteen patients (19 eyes) participated in the study. Nine eyes of seven patients were treated with IMP immediately followed by an intravitreal injection of 4 mg of TA (Group A), and 10 eyes of 8 patients were treated with IMP only (Group B). Patients had a mean follow-up of 6.9 months (range: 3 to 12 months). Patients underwent single or two sessions of IMP.

RESULTS

In Group A, visual acuity (VA) showed stability in 6 eyes (66.7%), improvement of VA in 2 eyes (22.2%), and worsening of VA in 1 eye (11.1%). Group B presented VA stability in 9 eyes (90%), and improvement in 1 eye (10%). In total, of the 15 patients (19 eyes) with IMP with or without intravitreal TA, 3 eyes (15.8%) showed improvement, 15 eyes (78.9%) stability, and 1 eye (5.3%) showed worsening of VA. A significant regression of the CNV and diminishing of subretinal fluid was demonstrated with fluorescein angiography and optical coherence tomography in both groups. No patient in Group A required retreatment. Four of 10 eyes (40%) in Group B required one retreatment during the study period.

CONCLUSIONS

ICG-mediated photothrombosis with and without intravitreal TA may provide stability or improvement in visual acuity and fundus findings in subfoveal CNV in AMD. Further evaluation in a multicenter, randomized, placebo-controlled clinical trial with longer follow-up is needed to accurately assess the safety and efficacy of this new treatment modality.

Basal deposits and drusen in eyes with age-related maculopathy: evidence for solid lipid particles

Neutral lipid, including esterified cholesterol, and apolipoproteins B and E are abundant in basal deposits and drusen of aged and age-related maculopathy (ARM) eyes. The principal component of basal linear deposit (BlinD), a specific ARM lesion, is membranous debris, which if actually derived from membranes cannot account for extracellular neutral lipid. We therefore used a lipid-preserving ultrastructural method to obtain improved images of membranous debris. Maculas from 44 human donors (71-96 yr) were preserved <7.5 hr after death. Blocks were post-fixed in 2% osmium or osmium-tannic acid-paraphenylenediamine (OTAP) to preserve neutral lipid for thin-section transmission electron microscopic (TEM) examination. Solid particles identified by OTAP were considered closest to the in vivo state of extracellular lipids. Micrographs were examined for intermediate forms, with greatest weight given to comparable images from different preparations of same or fellow eyes. Twenty eyes of older adults (12 with ARM including fellows treated with photodynamic and radiation therapies) had adequately preserved extracellular lipid. The exterior surface of membranous debris was thicker and more electron-dense than basal infoldings of retinal pigment epithelium (RPE) cells. By OTAP, individual membranous debris profiles were solid (diameters, 80-200 nm) and formed tracks across or aggregations within basal laminar deposits. Solid particles and/or pools of neutral lipid were visible in BlinD and drusen. When processed to preserve lipid, membranous debris resembles neither membranes of surrounding cells nor vesicles possessing aqueous interiors but rather solid particles. These results are consistent with recent evidence implicating lipoprotein particles of intra-ocular origin as a potential source of neutral lipids, including esterified cholesterol, in the specific lesions of ARM.

Optical coherence tomography in photodynamic therapy for subfoveal choroidal neovascularisation secondary to age related macular degeneration: a cross sectional study

AIMS

To introduce new terminology and validate its reliability for the analysis of optical coherence tomography (OCT) scans, compare clinical detection of cystoid macular oedema (CMO) and subretinal fluid (SRF) with OCT findings, and to study the effect of photodynamic therapy (PDT) on the foveal morphology.

METHODS

Patients with subfoveal, predominantly classic choroidal neovascularisation (CNV) secondary to age related macular degeneration (AMD) undergoing PDT were evaluated with refraction protocol best corrected logMAR visual acuity (VA), slit lamp biomicroscopy, stereoscopic fluorescein angiography (FFA), and OCT. New terminologies introduced to interpret the OCT scans were: neuroretinal foveal thickness (NFT), bilaminar foveal thickness (BFT), outer high reflectivity band thickness (OHRBT), intraretinal fluid (IRF), subretinal fluid (oSRF), and vitreomacular hyaloid attachment (VMHA).

RESULTS

Fifty six eyes of 53 patients were studied. VA was better in eyes with a thinner outer high reflectivity band (OHRBT) (p = 0.02) and BFT (p = 0.05). BFT was less in eyes that had undergone a greater number of PDT treatments (p = 0.04). There was poor agreement between OCT and clinical examination in the detection of CMO and subretinal fluid (kappa = 0.289 and kappa = 0.165 respectively). To validate the interpretation and measurements on OCT, two groups of 20 scans were analysed by two independent observers. There was good agreement between the observers in the detection of IRF, oSRF, and VMHA (p<0.001). Measurements of NFT and BFT had a high reproducibility, and of OHRBT reproducibility was low.

CONCLUSIONS

New terminology has been introduced and tested. OCT appears to be superior to clinical examination and FFA in the detection of CMO. In this study, better vision was associated with a thinner OHRBT and/or the absence of SRF giving insight into the biological effect of PDT.

Photodynamic therapy with verteporfin: a new treatment in ophthalmology

Photodynamic therapy (PDT) with verteporfin is a new treatment modality in ophthalmology that has previously shown its effectiveness in treatment of a variety of neoplastic pathologies. In this therapeutic approach, the photosensitizer verteporfin is activated by non-thermal laser light to obtain closure of neovascular structures. Preclinical and clinical studies have indicated that PDT is a safe, selective, and effective treatment for choroidal neovascularization in age-related macular degeneration. No significant damage to the neurosensory retina was found, which explains why PDT does not cause loss of visual acuity and may be used in a larger population than laser photocoagulation. This review summarizes the mechanisms of action of PDT, and the results of preclinical and clinical studies in ophthalmology.

Effects of verteporfin therapy on central visual field function

PURPOSE

To evaluate the effect of photodynamic therapy with verteporfin on the maintenance of central visual field function.

DESIGN

Randomized controlled clinical trial.

PARTICIPANTS

Forty-six consecutive patients with subfoveal choroidal neovascularization (CNV) caused by age-related macular degeneration including a classic component were randomly assigned. Thirty-three participants received standard verteporfin therapy, and 13 received placebo and laser treatment.

METHODS

The trial was performed as a single-center, double-masked study. Patients were examined before therapy and continuously in 3-month intervals during 2 years of follow-up. A scanning laser ophthalmoscope (SLO) was used to perform macular microperimetry. Absolute and relative scotomas were documented at each visit, and size was measured in square millimeters.

MAIN OUTCOME MEASURES

The change in size of central scotoma in the verteporfin group compared with the placebo group.

RESULTS

An absolute scotoma was seen in 88%, and a relative scotoma was seen in 100% of eyes before therapy. Absolute defects were associated with the classic CNV component localized angiographically. In the verteporfin group, the absolute scotoma grew from 2.5 mm(2) at baseline to a final size of 7.3 mm(2) at month 24. In the placebo group, the mean lesion size of the absolute scotoma enlarged from an initial size of 2.7 mm(2) to 31.5 mm(2) after 24 months. The relative scotoma increased from 7.9 mm(2) at baseline to 20.8 mm(2) at month 24 in the verteporfin group, whereas a progression from 8.5 mm(2) initially to 48.3 mm(2) at the final presentation was measured in the placebo group. Statistical analysis showed that both the mean absolute and relative scotoma sizes were significantly smaller in the verteporfin group than the placebo group for all intervals from 6 to 24 months (P<0.001).

CONCLUSIONS

Documentation of macular function with SLO perimetry demonstrated a significant benefit of verteporfin therapy for the preservation of the central visual field. Absolute and relative scotoma sizes remained smaller after therapy. This may influence reading ability and visual rehabilitation.

Immunohistopathologic evaluation of choroidal neovascular membranes following verteporfin-photodynamic therapy

PURPOSE

To evaluate the vascularization and proliferative activity in choroidal neovascular membranes due to age-related macular degeneration after verteporfin photodynamic therapy and submacular removal.

DESIGN

Interventional case series.

METHODS

In a retrospective review of seven patients who underwent removal of subfoveal classic choroidal neovascular membranes after treatment with photodynamic therapy 3 to 146 days earlier, membranes were stained for CD 34, CD 105, and Ki-67 and correlated with clinical pictures and fluorescein angiography.

RESULTS

Fluorescein angiography performed on the day of surgery disclosed nonperfusion of the treated area 3 days after photodynamic therapy, but perfusion and leakage were seen at greater post-photodynamic therapy intervals. Membranes excised 3 days after photodynamic therapy showed CD34 and CD105 positive, mostly occluded vessels. The endothelial cells appeared damaged. Ki-67 activity was low. In membranes excised 34 to 146 days after photodynamic therapy, all vessels appeared patent and were lined by healthy endothelial cells with strong expression of CD34 and CD105. Ki-67 expression was elevated after 34 days but decreased thereafter.

CONCLUSION

Photodynamic therapy did not cause a general or complete occlusion of vessels within the choroidal neovascular membranes, as suggested by fluorescein angiography 3 days postintervention, but the endothelial cells appeared to be severely damaged. Proliferative activity within these specimens was reduced. At longer intervals after photodynamic therapy, the fibrovascular tissue seemed to recover; perfusion, hyperfluorescence, and leakage of the choroidal neovascular membranes could be detected by fluorescein angiography. The clinical appearance showed a correlation with the immunohistologic characteristics of an increased proliferative activity and patent vascularization.

Verteporfin : a review of its use in the management of subfoveal choroidal neovascularisation

Verteporfin (Visudyne) therapy (photodynamic therapy with intravenous liposomal verteporfin) is the first treatment to effectively prevent the loss of visual acuity in patients with subfoveal choroidal neovascularisation (CNV) secondary to age-related macular degeneration (AMD), pathological myopia or presumed ocular histoplasmosis syndrome (POHS). In adult patients with classic subfoveal CNV or occult with no classic subfoveal CNV secondary to AMD, or subfoveal CNV secondary to pathological myopia or POHS, verteporfin therapy slows or prevents loss of visual acuity. In well designed clinical trials, verteporfin therapy was superior to placebo in patients with subfoveal classic-containing CNV and occult with no classic CNV secondary to AMD at 12 and/or 24 months (Treatment of Age-related macular degeneration with Photodynamic therapy [TAP] Investigation and Verteporfin In Photodynamic therapy [VIP-AMD] trial) and in patients with pathological myopia at 12 months (Verteporfin In Photodynamic therapy [VIP-PM] trial). Limited data suggest that verteporfin therapy also prevents loss of visual acuity in patients with subfoveal CNV secondary to POHS. Verteporfin therapy was generally well tolerated in clinical trials; most adverse events were mild to moderate in intensity and transient. The most frequently reported verteporfin therapy-related adverse events (incidence >2%) were visual disturbance, injection-site reactions, photosensitivity reactions and infusion-related back pain. Approximately 5% of patients with occult with no classic subfoveal CNV secondary to AMD reported severe vision decrease within 7 days of treatment in clinical trials; 3 months later, several patients had recovered some of this loss.

CONCLUSION

Photodynamic therapy with verteporfin, the first photosensitiser approved for the treatment of subfoveal CNV, is a well tolerated treatment that stabilises or slows visual acuity loss in adult patients with predominantly classic or occult with no classic subfoveal CNV secondary to AMD, and subfoveal CNV secondary to pathological myopia or POHS. Thus, verteporfin therapy provides a valuable option for the management of these patients for whom treatment options are few, and should be considered as a first-line therapy in these difficult-to-manage conditions.

Thérapie photodynamique et DMLA : arguments pratiques sur la base de cas cliniques pour retraiter ou surveiller lors du suivi

Clinical and angiographic progression after photodynamic therapy (PDT) is usually slow, sometimes fluctuating and therefore difficult to evaluate. After several sessions of PDT, angiographic follow-up remains the basis for therapeutic management involving either a new PDT session or an alternative treatment. It remains difficult, however, to evaluate the activity and progression potential of the remaining neovessels. Imaging (angiography, optical coherence tomography) and functional data both contribute to the therapeutic decision. Certain patients require several sessions for a progressive reduction of the exudation. For others, the persistence of metamorphopsias and accentuation of the scotoma despite the treatment may entail alternative treatment. Thus, a perifoveal photocoagulation can be proposed to limit the extension of the scotoma if after a reasonable number of sessions, central visual acuity is not recovered; direct photocoagulation of a persistent active neovascular contingent, distant from the fixation zone (foveal or exenterated) can be proposed if it remains on the border of a stabilized lesion; the treatment of a feeder vessel can be proposed if it becomes visible and is associated with active neovessels with a persistent central serous detachment of the neuroretina. Lastly, performance status and patient wishes are important elements in the overall therapeutic project, especially if the eye involved is the second eye, in view of quickly initiating low-vision rehabilitation.

Clinicopathological findings of choroidal neovascularisation following verteporfin photodynamic therapy

AIMS

To report the clinicopathologic findings of surgically excised choroidal neovascularisation (CNV) three days after verteporfin photodynamic therapy (PDT).

METHODS

In three patients (three eyes) with age related macular degeneration, the CNV was surgically removed three days after PDT. The CNV specimens were examined by light microscopy.

RESULTS

The patients had subfoveal classic CNV. Fluorescein angiography revealed non-perfusion of the CNV after PDT and before surgery in all eyes. The light microscopy of the CNV membranes showed swollen and damaged endothelium. Thrombus formation or vascular occlusion in the CNV vessels was not detected.

CONCLUSION

PDT did not cause a thrombosis of the vessels within the CNV three days after PDT. Severe endothelial damage of the CNV was observed and is likely a primary effect of PDT. Non-perfusion of the CNV at this stage is possibly secondary to occlusion at a deeper level, namely the underlying feeding choroid.

Histological findings of a surgically excised myopic choroidal neovascular membrane after photodynamic therapy. A case report

BACKGROUND

The authors describe a myopic choroidal neovascular membrane excised 4 months after photodynamic therapy (PDT).

METHODS

A 68-year-old woman with classic choroidal neovascularization (CNV) due to pathologic myopia underwent PDT with verteporfin in the left eye. Four months after treatment a full-thickness macular hole was diagnosed in the same eye and the patient underwent vitrectomy with submacular membranectomy. The subfoveal membrane was studied by light microscopy and immunohistochemical techniques.

RESULTS

Light microscopy showed a thin fibrovascular membrane covered by residual retinal pigment epithelium. The membrane contained homogeneous matrix with small collagen bundles, fibroblasts and small blood vessels. The distribution of blood vessels was nonuniform: extravasated red blood cells, macrophages and other inflammatory elements were not present in the fibrous matrix. Endothelial cells were highlighted by CD34 immunostaining and did not show any significant alteration. There was no evidence of inflammatory cells or thrombosis inside vascular lumina.

CONCLUSIONS

Histologic examination of the neovascular membrane showed features similar to those of surgically excised myopic CNV without PDT treatment. Our findings suggest that PDT-induced occlusion is temporary. Fluorescein leakage from CNV after a single PDT treatment can be considered as an sign of blood vessel regrowth or recanalization indicating that multiple treatments are necessary.

Photodynamic therapy for age-related macular degeneration in a clinical setting: visual results and angiographic patterns

PURPOSE

To evaluate the visual outcome of patients with subfoveal choroidal neovascularization due to age-related macular degeneration, who received photodynamic therapy (PTD) in a clinical setting and to identify potential predictive visual and angiographic factors.

DESIGN

Interventional case series.

METHODS

The study included 74 patients with subfoveal choroidal neovascularization who underwent PDT from January 2000 to March 2001 and completed at least 1 year follow-up. All patients received verteporfin PDT and were followed clinically, with fluorescein angiography (74 eyes), and with indocyanine green angiography (65 eyes). A review of the medical records and angiograms was performed.

RESULTS

Mean follow-up was 15.6 months. Patients received a mean of 3.4 treatments per year. Sixty-six percent lost less than 3 Snellen lines of visual acuity. Three patients (4%) experienced profound visual acuity loss to finger counting. Final visual acuity was positively correlated with lesion size and visual acuity at presentation. Visual outcome was worse in the presence of cystoid macular edema. On indocyanine green angiography, a round hypofluorescent spot was seen at the site of the PDT, with maintenance of medium and large choroidal vessels.

CONCLUSION

Smaller lesion size and better visual acuity at presentation were good predictive signs, whereas cystoid macular edema was found to be a poor prognostic sign for visual outcome following PDT.

The changes of multifocal electroretinography in the early stage of photodynamic therapy for choroidal neovascularization

To investigate short-term changes in the multifocal electroretinography (ERG) recordings after photodynamic therapy (PDT) for choroidal neovascularization (CNV), 16 patients (17 eyes) with classic CNV confirmed by fluorescein angiography (FA) and indocyanine green angiography (ICGA), including 11 cases (12 eyes) of exudative age-related macular degeneration (AMD), two cases (two eyes) of pathological myopia and three cases (three eyes) of idiopathic causes, were treated using PDT with verteporfin. The multifocal ERGs of these patients were tested with VERIS Science 4.0 imaging system. The latencies and average response densities of all six ring retinal regions were measured and compared before PDT and 3 or 7 days after PDT. The latencies and amplitude densities of the N1 and P1 waves in all six rings remained unchanged at 3 or 7 days post-treatment (p > 0.05). Therefore, there is no significant evidence to suggest an adverse effect from PDT for classic CNV on the outer retinal function in the early stage of treatment, with the aid of the multifocal ERG recordings.

Spotlight on Verteporfin in Subfoveal Choroidal Neovascularisation1

Verteporfin (Visudyne) therapy (photodynamic therapy with intravenous liposomal verteporfin) is the first treatment to effectively prevent the loss of visual acuity in patients with subfoveal choroidal neovascularisation (CNV) secondary to age-related macular degeneration (AMD), pathological myopia or presumed ocular histoplasmosis syndrome (POHS). In adult patients with classic subfoveal CNV or occult with no classic subfoveal CNV secondary to AMD, or subfoveal CNV secondary to pathological myopia or POHS, verteporfin therapy slows or prevents loss of visual acuity. In well designed clinical trials, verteporfin therapy was superior to placebo in patients with subfoveal classic-containing CNV and occult with no classic CNV secondary to AMD at 12 and/or 24 months (Treatment of Age-related macular degeneration with Photodynamic therapy [TAP] Investigation and Verteporfin In Photodynamic therapy [VIP-AMD] trial) and in patients with pathological myopia at 12 months (Verteporfin In Photodynamic therapy [VIP-PM] trial). Limited data suggest that verteporfin therapy also prevents loss of visual acuity in patients with subfoveal CNV secondary to POHS. Verteporfin therapy was generally well tolerated in clinical trials; most adverse events were mild to moderate in intensity and transient. The most frequently reported verteporfin therapy-related adverse events (incidence >2%) were visual disturbance, injection-site reactions, photosensitivity reactions and infusion-related back pain. Approximately 5% of patients with occult with no classic subfoveal CNV secondary to AMD reported severe vision decrease within 7 days of treatment in clinical trials; 3 months later, several patients had recovered some of this loss.

CONCLUSION

Photodynamic therapy with verteporfin, the first photosensitiser approved for the treatment of subfoveal CNV, is a well tolerated treatment that stabilises or slows visual acuity loss in adult patients with predominantly classic or occult with no classic subfoveal CNV secondary to AMD, and subfoveal CNV secondary to pathological myopia or POHS. Thus, verteporfin therapy provides a valuable option for the management of these patients for whom treatment options are few, and should be considered as a first-line therapy in these difficult-to-manage conditions.

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.

Macular relocation after photodynamic therapy for recurrent choroidal neovascular membrane: visual results and histopathological findings

BACKGROUND/AIMS

The findings in a patient treated with photodynamic therapy (PDT) followed by macular relocation surgery (MRS) are presented.

METHODS

Histopathological evaluation of the choroidal neovascular membrane (CNV) specimen including immunohistochemical assessment.

RESULTS

Microscopy revealed one CNV area that was richly vascular with attached retinal pigment epithelial cell monolayer and another area that was made up of densely collagenous avascular tissue with adherent fragments of Bruch's membrane and glial elements.

CONCLUSION

The findings suggest that the PDT treated part of the CNV may have been adherent to the neuroretina and may have contributed to the formation of the macular hole. Caution is advised when considering MRS for CNV previously treated PDT.

Immediate indocyanine green angiography and optical coherence tomography evaluation after photodynamic therapy for subfoveal choroidal neovascularization

PURPOSE

To better understand the mechanisms of action of photodynamic therapy (PDT) with verteporfin for subfoveal choroidal neovascularization (CNV), the authors evaluated the retinal and choroidal response immediately after treatment with serial optical coherence tomography (OCT) and indocyanine green angiography (ICGA).

METHODS

This study was a prospective, noncomparative case series. PDT was performed on nine eyes of nine consecutive patients who presented with subfoveal CNV due to age-related macular degeneration, and serial evaluation with OCT as well as ICGA was performed at 20-minute intervals for the first 2 hours and then at 1 week, 1 month, and 3 months.

RESULTS

In the first 2 hours after PDT, OCT showed an increase in the thickness of the retina in the treatment area due to fluid leakage from the neovascular complex as confirmed by ICGA. At 1 week, marked reduction of intraretinal/subretinal fluid was observed in all patients. Neovascular complex nonperfusion by ICGA was associated with some degree of choroidal hypoperfusion in the treatment area. Return of the foveal contour by OCT was optimal after 1 month of treatment. At 3 months, choroidal reperfusion by ICGA and recurrent intraretinal/subretinal fluid by OCT were observed.

CONCLUSIONS

Serial OCT and ICGA evaluation after PDT suggests that the initial successful CNV nonperfusion as shown by fluorescein angiography at 1 week occurs by means of selective PDT damage to the lesion and/or reduced choroidal blood flow in the treatment area, thereby decreasing intraretinal/subretinal fluid and facilitating restoration of the retinal architecture.

Clinicopathologic study after submacular removal of choroidal neovascular membranes treated with verteporfin ocular photodynamic therapy

PURPOSE

To report the clinicopathologic findings after submacular removal of choroidal neovascular membranes (CNV) treated with verteporfin ocular photodynamic therapy.

DESIGN

Interventional case series.

METHODS

Retrospective review of eight eyes of eight patients who underwent submacular surgery for CNV after having previously received verteporfin ocular photodynamic therapy for presumed ocular histoplasmosis (one patient), age-related macular degeneration ([AMD] three patients) pathologic myopia (two patients), punctate inner choroiditis (one patient), and idiopathic CNV (one patient). All cases had undergone ocular photodynamic therapy with verteporfin using standard protocols. Six of eight patients suffered a submacular hemorrhage after ocular photodynamic therapy, and two of eight patients refused further ocular photodynamic therapy. All patients subsequently had submacular surgery with removal of the CNV. One membrane was routinely processed, sectioned, and stained with hematoxylin and eosin. Five membranes were stained with toluidine blue for light microscopic examination. Semithin (1.0 microm) sections were cut and stained with uranyl acetate-lead citrate for transmission electron microscopy.

RESULTS

Choroidal neovascular membranes were removed at 3 days (presumed ocular histoplasmosis), 29 days (punctate inner choroiditis), 63 days (AMD, pathologic myopia), 66 days (AMD), 107 days (pathologic myopia), 116 days (AMD), and 152 days (idiopathic) after verteporfin ocular photodynamic therapy. Histopathologic and ultrastructural examination showed areas of vascular occlusion at 3 days that were not seen at later time points. All specimens had patent CNV. There were signs of vascular damage with extravasated erythrocytes and fibrin, pigment clumping in cells, and inflammatory cells in all but the 3-day specimen.

CONCLUSIONS

This case series presents data only from patients who refused repeat treatment with ocular photodynamic therapy or who developed submacular hemorrhage after initial photodynamic therapy. Histopathologic evaluation of CNV 3 days after verteporfin ocular photodynamic therapy showed partial vascular occlusion that was not present in later specimens. These later specimens demonstrated evidence of vascular damage. Verteporfin ocular photodynamic therapy does not appear to lead to permanent and complete occlusion of the CNV. Thus, treatments that lead to permanent closure of CNV without damage to the retinal pigment epithelium and sensory retina are still needed.

Angiographic features after photodynamic therapy for choroidal neovascularisation in age related macular degeneration and pathological myopia

AIM

To describe the angiographic features after photodynamic therapy (PDT) with verteporfin in choroidal neovascularisation (CNV) associated both with age related macular degeneration (AMD) and pathological myopia (PM).

METHODS

36 patients affected by subfoveal CNV in AMD and 25 patients with subfoveal CNV in PM underwent an ophthalmological examination including fluorescein angiography (FA) and indocyanine green angiography (ICGA) using the IMAGEnet System. Post-PDT examinations were performed 7, 30, and 90 days later.

RESULTS

The typical angiographic aspect after PDT for AMD related CNV was a round hypofluorescence visible both on FA and on ICGA, which included both CNV and the surrounding tissues and corresponded to the area exposed to laser light. In PM the CNV appeared hypofluorescent during the early phases and gradually became hyperfluorescent during the late phases on FA, whereas on ICGA it was detectable in its whole extension as a hyperfluorescent lesion since the early phases. Differently from AMD, there was no round hypofluorescence surrounding the CNV on FA or on ICGA. Moreover, five patients in the AMD group showed hot spots on ICGA, which spontaneously disappeared during the follow up. Classic and occult components of the AMD related CNV revealed a different angiographic response to PDT, showing with the latter only a partial closure 1 week after PDT followed by a complete reopening at the first month in 100% of cases.

CONCLUSION

The post-PDT hypofluorescence typical of AMD related CNV, especially visible on FA, might be secondary to a combination of choriocapillary occlusion and masking effect due to swelling of retinal pigment epithelium cells. Hot spots in the AMD affected patients could be interpreted as the expression of a non-thermal choroidal vasculitis secondary to PDT.

Age-related maculopathy: pathogenetic features and new treatment modalities

A considerable amount of new information on putative pathogenetic mechanisms in age-related maculopathy and degeneration has emerged in recent years. This comprises experimental studies on retinal pigment epithelium (RPE) and rod photoreceptor ageing, lipofuscin accumulation, the roles of oxidative stress and free radical formation, as well as antioxidants and other defensive mechanisms operating against environmental factors and ageing. The current application of photodynamic therapy (PDT) using verteporfin marks a new era in the treatment of subfoveal classical choroidal neovascularization. Several new treatment modalities, such as transpupillary thermotherapy (TTT) and anti-vascular endothelial growth factor (VEGF) agents for inhibition of neovascularization, have emerged and are undergoing multicentre clinical trials. A period of dynamic development in this field has commenced.