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

Is There any Relationship between Photodynamic Therapy for Exudative Age-Related Macular Degeneration and Choroidal Neovascularization Recurrence? A Rationale for Combined Treatments

Purpose

Photodynamic therapy (PDT) is the treatment of choice for subfoveal choroidal neovascularization (CNV) in age-related macular degeneration (ARMD). Interpretation of PDT mechanism of action is not yet fully understood and causes of CNV recurrences are unclear. The authors have conducted a retrospective analysis of fluorescein and indocyanine green angiographies in patients treated with multiple PDT in order to identify risk factors for recurrence.

Methods

A total of 342 eyes of 342 patients (207 women and 135 men) with ARMD and subfoveal CNV were treated with at least two PDT. Angiographic (fluorescein and indocyanine green) features of recurrences were confronted to pretreatment examinations in all patients. RESULTS. Post-PDT angiographies showed in all eyes a dark circle corresponding to the laser spot even 1 year after treatment. Persistence or progressive regrowth of CNV developed in an area adjacent or corresponding to the original lesion, without any specific relationship with the location of fluorescein and indocyanine green late leakage or with presence of abnormal fluorescence due to pigment abnormalities. At the 3-month angiographic follow-up, 23 patients (6.7%) showed a recurrent CNV resembling shape and dimension of the laser spot used for the PDT treatment.

Conclusions

The authors failed to identify angiographic signs helpful to predict the risk of CNV persistence or recurrence. PDT leaves minor but persistent changes in the choroidal vasculature within the treatment area. In some cases, the recurrent CNV seems to be related to the laser spot of the PDT.

Changes of outer retinal microstructures after photodynamic therapy for chronic central serous chorioretinopathy

PURPOSE

To evaluate the morphological changes in retinal microstructures following modified photodynamic therapy (PDT) for chronic central serous chorioretinopathy.

SUBJECTS AND METHODS

Retrospective study of 21 consecutive eyes (age, 59±8.0 years [mean ± SD]) of 21 patients with chronic central serous chorioretinopathy. Inner foveal thickness (the distance between the internal limiting membrane and external limiting membrane), photoreceptor outer segment (PROS) length at the point without serous retinal detachment and choroidal thickness were assessed with enhanced depth imaging optical coherence tomography before treatment and at 1, 3 and 6 months after modified PDT.

RESULTS

Six eyes had half-dose and 15 eyes had half-fluence PDT. PROS length within the irradiated area was significantly decreased by 3.9% at 1 month compared with that before modified PDT (43.5±5.72 and 40.5±7.53, P=0.020 [paired t-test]) and returned to baseline length at 3 and 6 months (43.0±5.42 and 43.5±4.33 μm [mean ± SD]; P=0.53 and 1.00 [paired t-test]). PROS length of the nonirradiated area at 1, 3 and 6 months after modified PDT did not significantly differ from that before PDT (41.8±6.35, 41.4±5.33, 41.9±4.67 and 42.3±4.26 μm [mean ± SD]; P=0.66, 0.90 and 0.60, respectively [paired t-test]). There was no significant change in inner foveal thickness during the observation period. At all time points, choroidal thickness was significantly thinner than it was before PDT (P<0.001, paired t-test).

CONCLUSION

Modified PDT may cause mild temporary microstructural changes.

Half-dose photodynamic therapy for chronic central serous chorioretinopathy evaluated by focal macular electroretinograms

PURPOSE

To evaluate the effect of half-dose verteporfin photodynamic therapy (hPDT) on the physiology of the macula determined by focal macular electroretinograms (FMERGs) in eyes with chronic central serous chorioretinopathy (CSC).

METHODS

Fourteen eyes of 13 patients with chronic CSC were treated with hPDT. The best-corrected visual acuity (BCVA) was measured, and optical coherence tomography (OCT) and FMERGs were performed at the baseline, and at 4 days, 1, 3, 6, and 12 months after the hPDT.

RESULTS

The subreitnal fluid was resolved in 12 of the 14 eyes after the hPDT. The amplitude of the a-wave at 12 months was significantly increased by 1.28 times over that at the baseline. The amplitude of the b-wave was also increased but not significantly (P = 0.055). The implicit time of the a-wave was significantly reduced at 6 months, and that of the b-wave at 3 months. The amplitudes of the oscillatory potentials did not change significantly during the 12-month follow-up period.

CONCLUSIONS

hPDT led to an improvement in the FMERGs for at least 12 months without a transient depression of the FMERGs in eyes with chronic CSC. hPDT can be used safely to treat eyes with CSC.

Photodynamic Therapy and Intravitreal Bevacizumab with Versus without Triamcinolone for Neovascular Age-related Macular Degeneration; a Randomized Clinical Trial

PURPOSE

To compare the outcomes of photodynamic therapy (PDT) combined with intravitreal bevacizumab (IVB) with versus without intravitreal triamcinolone (IVT) in neovascular age-related macular degeneration (AMD).

METHODS

Eighty-four eyes with active CNV secondary to AMD with no prior treatment were enrolled and followed for 1-year. Eligible eyes were randomly assigned to either PDT/IVB or PDT/IVB/IVT. The main outcome measure was change in best-corrected visual acuity (BCVA).

RESULTS

Mean patient age was 71 ± 9 years. BCVA changes from baseline were statistically significant in both study arms at all follow-up intervals, however no significant difference was observed between the two groups regarding BCVA changes at week 12 (95% CI:-0.11-0.12 LogMAR) and other time points (all P > 0.6). Mixed model analysis revealed a significant effect from age (P < 0.001), pigment epithelial detachment (P = 0.009) and baseline BCVA (P < 0.001) on visual improvement. Significant central macular thickness (CMT) reduction occurred at all-time points as compared to baseline in both groups which was comparable between the study arms. There was no significant difference between the study arms in terms of retreatment rate (P = 0.1) and survival to the first repeat IVB injection (P = 0.065).

CONCLUSION

Additional low-dose IVT to a PDT/IVB regimen for neovascular AMD provided no beneficial effects in terms BCVA or CMT, yet demonstrated a trend toward extending the injection-free period.

Inter-observer agreement for spectral- and time-domain optical coherence tomography image grading: a prospective study

The purpose of this study was to compare inter-observer agreement of Stratus™ OCT versus Spectralis™ OCT image grading in patients with neovascular age-related macular degeneration (AMD). Thirty eyes with neovascular AMD were examined with Stratus™ OCT and Spectralis™ OCT. Four different scan protocols were used for imaging. Three observers graded the images for the presence of various pathologies. Inter-observer agreement between OCT models was assessed by calculating intra-class correlation coefficients (ICC). In Stratus™ OCT highest interobserver agreement was found for subretinal fluid (ICC: 0.79), and in Spectralis™ OCT for intraretinal cysts (IRC) (ICC: 0.93). Spectralis™ OCT showed superior interobserver agreement for IRC and epiretinal membranes (ERM) (ICC(Stratus™): for IRC 0.61; for ERM 0.56; ICC(Spectralis™): for IRC 0.93; for ERM 0.84). Increased image resolution of Spectralis™ OCT did improve the inter-observer agreement for grading intraretinal cysts and epiretinal membranes but not for other retinal changes.

One-year choroidal thickness results after photodynamic therapy for central serous chorioretinopathy

PURPOSE

To retrospectively evaluate choroidal thickness 1 year after photodynamic therapy in eyes with central serous chorioretinopathy using optical coherence tomography.

METHODS

Central serous chorioretinopathy was diagnosed using fluorescein angiography, and indocyanine green angiography was used to evaluate choroidal vascular hyperpermeability. We measured the subfoveal choroidal thickness using enhanced depth imaging optical coherence tomography.

RESULTS

Thirteen eyes (13 patients; average age, 56.8 years) with central serous chorioretinopathy were observed 1 year after half-dose photodynamic therapy with verteporfin. The mean subfoveal choroidal thickness decreased significantly from 397 ± 108 μm at baseline to 323 ± 120 μm at 1 month, 312 ± 117 μm at 3 months, 317 ± 117 μm at 6 months, and 321 ± 122 μm at 1 year (P < 0.01, for each comparison with baseline). However, the subfoveal choroid thickness significantly increased 2 days after photodynamic therapy to 441 ± 120 (P < 0.01) compared with baseline. Central serous chorioretinopathy did not recur in any patient. Indocyanine green angiography images at 3 months showed less choroidal vascular hyperpermeability compared with baseline.

CONCLUSION

Half-dose photodynamic therapy for central serous chorioretinopathy resulted in thinner subfoveal choroidal thickness 1 month after treatment, decreased the choroidal vascular hyperpermeability, and maintained the remission for 1 year. Enhanced depth imaging optical coherence tomography was helpful for monitoring the pathophysiologic choroidal changes in central serous chorioretinopathy.

Transpupillary thermotherapy for atypical central serous chorioretinopathy

BACKGROUND

Central serous chorioretinopathy (CSC) has been traditionally treated with laser photocoagulation. We thought that transpupillary thermotherapy (TTT) utilizing a lower temperature than that of conventional laser photocoagulation might minimize permanent retinal and choroidal damage. Studies suggest that undesirable effects on vision due to TTT are minimal even if it is applied to foveal and/or parafoveal lesions when TTT requires a larger irradiation spot. The aim of this study was to evaluate the efficacy of TTT in the management of atypical CSC.

METHODS

We defined atypical CSC as bullous retinal detachment with diffuse or several leakages, severe leakage with fibrin formation under serous retinal detachment, or leakage within a pigment epithelium detachment. Eight consecutive patients with atypical CSC underwent visual acuity testing, ophthalmic examination, color photography, fluorescein angiography, and optical coherence tomography to evaluate the results of transpupillary thermotherapy. Retreatment of atypical CSC was based on ophthalmic examination, optical coherence tomography, and fluorescein angiography. TTT was performed on the leaking spots shown in fluorescein angiography, with a power of 50-250 mW, spot size of 500-1200 μm, and exposure time of 13-60 seconds to minimize retinal damage.

RESULTS

In five of eight affected eyes, serous detachments completely resolved within 1 month after the initial TTT. One eye had persistent subretinal fluid and required a second TTT treatment. Two eyes showed no resolution of CSC and were treated by conventional photocoagulation. Initial best-corrected visual acuity (BCVA) ranged from 20/600 to 20/20 (mean, 20/40; median, 20/30). Final BCVA ranged from 20/200 to 20/20 (mean, 20/25; median, 20/20). BCVA improved in all cases. Only two eyes with persistent subretinal fibrin and existing retinal pigment epithelial alternations in macular area showed limited improvement of BCVA despite the absence of subretinal exudation. The presence of retinal attachment was confirmed by optical coherence tomography in six eyes (75%).

CONCLUSIONS

TTT seems to be effective for the treatment of atypical CSC in the short term. Additional studies are necessary to evaluate the long-term effectiveness and safety.

Reactive macular edema and acute visual loss after photodynamic therapy on the same day of fluorescein angiography

Reactive macular edema can occur following photodynamic therapy (PDT) in patients who have undergone fluorescein angiography (FA) on the same day. It might be better not to perform PDT on the same day of FA to avoid side effects. The safety interval between FA and PDT should be at least 24 hours, considering fluorescein retention in the body.

Severe decrease in visual acuity with choroidal hypoperfusion after photodynamic therapy

Background

Photodynamic therapy (PDT) is considered a selective method of treatment which works in areas of choroidal neovascularization (CNV); however, there are reports of choroidal hypoperfusion after PDT. This paper presents a clinical case of choroidal circulation disturbances caused by PDT, accompanied by CNV progression.

Case Report

The patient, a 75-year-old woman, was qualified for PDT in the right eye – first treatment due to progression of occult CNV. Best corrected visual acuity (BCVA) in the right eye at baseline was +0.3 logMAR. After PDT, a rapid decrease in visual acuity to +0.7 logMAR in the right eye was observed, central choroidal hypoperfusion in fluorescein angiography (FA) with subretinal fluid appeared and, as a consequence, progression of neovascular age-related macular degeneration (AMD). After stabilizing the local state through conservative therapy, a decision was made to treat the right eye with intravitreal injections of vascular endothelial growth factor (VEGF) inhibitor. During a 12-month period of observation, 7 doses of ranibizumab were administered. A regression in activity of wet AMD was observed, with visual acuity of +0.6 logMAR.

Conclusions

Choroidal circulation disturbance after PDT is possible and has to be taken into account. Sporadically, it can lead to an acute decrease in visual acuity and local state. After stabilization of AF and optical coherence tomography imaging, further treatment of neovascular AMD with intravitreal injections of anti-VEGF agents should be considered.

Subfoveal retinal and choroidal thickness after verteporfin photodynamic therapy for polypoidal choroidal vasculopathy

PURPOSE

To evaluate the morphologic retinal and choroidal changes after verteporfin photodynamic therapy (PDT) with and without ranibizumab for polypoidal choroidal vasculopathy using spectral-domain optical coherence tomography.

DESIGN

Retrospective, comparative series.

METHODS

The enhanced depth imaging optical coherence tomography technique was used in this retrospective, comparative series to measure the subfoveal retinal and choroidal thicknesses before and after treatment.

RESULTS

Twenty-seven eyes with polypoidal choroidal vasculopathy were examined retrospectively. Sixteen eyes were treated with PDT monotherapy (PDT group). Eleven eyes were treated with PDT after intravitreal ranibizumab injection (ranibizumab plus PDT group). The polypoidal lesions regressed in all cases at 3 months. The mean retinal thickness, including the retinal detachment, increased from 401 ± 157 μm before treatment to 506 ± 182 μm 2 days after PDT (P<.001) and decreased to 365 ± 116 μm by 1 week after treatment (P=.03) and 265 ± 127 μm by 6 months after treatment (P<.001). The mean choroidal thickness increased from 269 ± 107 μm before treatment to 336 ± 96 μm 2 days after PDT treatment (P < .001 compared with baseline) and decreased to 262 ± 96 μm by 1 week after treatment (P=.24) and 229 ± 104 μm by 6 months (P<.001). Although the choroidal thickness showed a similar trend with both therapies, the retinal thickness in the ranibizumab plus PDT group remained thinner than that in the PDT group until 6 months after treatment.

CONCLUSIONS

PDT was associated with decreased retinal and choroidal thicknesses. Combination therapy reduced the transient exudation after PDT in some cases, and monthly intravitreal ranibizumab injections maintained retinal thinning and seemed to improve vision better than PDT monotherapy.

Acute severe visual decrease after photodynamic therapy with verteporfin: spectral-domain OCT features

In this report, spectral-domain optical coherence tomography (OCT) was used to characterize the acute morphologic alterations that occur when photodynamic therapy with verteporfin results in an acute severe visual decrease. The clinical and imaging records of a patient with neovascular age-related macular degeneration who suffered this complication were reviewed. Using spectral-domain OCT, two relatively distinct subretinal fluid compartments were visualized: a sparsely hyperreflective pocket of subretinal fluid overlying the fibrovascular pigment epithelial detachment, consistent with fibrinous exudation, and a more homogeneously hyporeflective compartment at the periphery of the choroidal neovascular lesion, consistent with serous exudation. The higher axial resolution, and greater sensitivity, of spectral-domain OCT allows improved visualization of the subretinal space. As experience with spectral-domain OCT grows, new parameters will emerge-such as those related to subretinal fluid-that will facilitate improvements in both the qualitative and quantitative evaluation of macular disease.

Effect of photodynamic therapy alone or combined with posterior subtenon triamcinolone acetonide or intravitreal bevacizumab on choroidal hypofluorescence by indocyanine green angiography

PURPOSE

Choroidal hypofluorescence has been reported beneath the photodynamic therapy (PDT) site in clinical studies. We evaluated the choroidal hypofluorescence after combined PDT with posterior subtenon injection of triamcinolone acetonide or PDT with an intravitreal injection of bevacizumab for age-related macular degeneration.

METHODS

Two hundred and forty-two eyes with a subfoveal choroidal neovascularization caused by age-related macular degeneration were studied. Ninety-two eyes underwent PDT alone, 90 eyes underwent PDT with sub-Tenon injection of triamcinolone acetonide, and 60 eyes underwent PDT with intravitreal injection of bevacizumab. Verteporfin-induced choroidal hypoperfusion was determined by indocyanine green angiograms. The intensity of the diffuse fluorescence within the PDT site away from the choroidal neovascularization lesion and from the normal retina just peripheral to the optic disk was measured by densitometry (Topcon IMAGEnet computer system, Topcon, Tokyo, Japan) in the indocyanine green angiogram images obtained at 10 minutes 3 months after the PDT. The ratio of the average brightness of the retina within the PDT area to that of the retina peripheral to the optic disk (irradiated/nonirradiated retinal brightness ratio) was calculated for each angiogram.

RESULTS

The irradiated/nonirradiated retinal brightness ratio of the angiograms was 0.96 in the PDT-alone group, 0.85 in the sub-Tenon injection of triamcinolone acetonide-PDT group, and 0.89 in the intravitreal injection of bevacizumab-PDT group (Kruskal-Wallis H test, P < 0.05).

CONCLUSION

The degree of choroidal hypofluorescence in the indocyanine green angiogram images 3 months after PDT in the sub-Tenon injection of triamcinolone acetonide and intravitreal injection of bevacizumab group was higher than that of PDT-alone group. Sub-Tenon injection of triamcinolone acetonide and intravitreal injection of bevacizumab can prolong the duration of the choroidal hypofluorescence after PDT.

Time-course and characteristic morphology of retinal changes following combination of verteporfin therapy and intravitreal triamcinolone in neovascular age-related macular degeneration

PURPOSE

To identify characteristic morphological changes of the retina over time and the association with visual function after combined photodynamic therapy (PDT) and intravitreal triamcinolone (IVTA).

METHODS

In this retrospective study, 40 patients (40 eyes) were treated with PDT and same-day IVTA. Optical coherence tomography (OCT), fluorescein angiography (FA) and evaluation of distance visual acuity (VA) were performed. The anatomical changes within intra- and subretinal compartments and their detailed analysis and grading were the main outcome measures.

RESULTS

Intraretinal fluid (IRF) and subretinal fluid (SRF) by OCT decreased until 3 months (p < 0.01). At month 3, intraretinal cystoid spaces (ICS) had resolved or decreased in 84% of eyes, SRF in 58% and pigment epithelial detachment (PED) in 50%. Mean best-corrected VA (BCVA) improved significantly at month 1 (p < 0.01). Mean central retinal thickness (CRT) increased from 334 microm at baseline to 439 microm at day 1 (p = 0.03) before decreasing to 286 microm at day 7 (p = 0.06), 233 microm at month 1 (p = 0.001) and 255 microm at month 3 (p = 0.001).

CONCLUSION

Combined verteporfin/IVTA therapy induces distinct time-related effects on the retina within the different intra- and subretinal compartments.

Combination therapy using verteporfin and ranibizumab; optimizing the timing in the CAM model

Combining photodynamic therapy (PDT) using verteporfin (Visudyne) with ranibizumab (Lucentis) can optimize the overall treatment outcome by providing more efficacy in vessel closure, and thus reduce the need for retreatment in patients with wet age-related macular degeneration. In this preclinical study in the chorioallantoic membrane (CAM) of the chicken embryo, we compare the vascular occlusion effects of verteporfin and ranibizumab as monotherapies with those observed in the combined therapy. In order to optimize the combination therapy, we varied the timing and sequence of the PDT and antivascular endothelial growth factor modalities. We observed that 1 day after PDT, the smaller blood vessels (Ø < 70 microm) of the CAM were selectively occluded, but as early as 2 days after PDT, both significant reperfusion and regrowth of new vessels were observed. Both these phenomena could be significantly delayed by application of ranibizumab. Ranibizumab itself did not induce any vascular occlusion. Under the applied conditions of combination therapy, the occlusion of the targeted blood vessels could be significantly extended to 3 days in this model compared with 1 day in the case of verteporfin monotherapy. Thus, in the present preclinical study, we demonstrate that for the applied conditions, the optimal time to administer ranibizumab is 24 h after PDT.

Ocular haemodynamic changes after single treatment with photodynamic therapy assessed with non-invasive techniques

PURPOSE

To investigate in patients with neovascular age-related macular degeneration (ARMD) the changes in ocular perfusion caused by single treatment with photodynamic therapy (PDT) by different non-invasive methods; to evaluate correlations between relative changes of ocular haemodynamic parameters after PDT among each other and compared to morphological parameters; and to assess this in relation to early changes of visual acuity.

METHODS

STUDY POPULATION

17 consecutive patients with subfoveal choroidal neovascularization (CNV) caused by ARMD scheduled for PDT without previous PDT treatment (four patients with predominantly classic CNV and 13 patients with occult CNV).

OBSERVATION PROCEDURES

best-corrected visual acuity (before PDT, 6 and 8 weeks after PDT), fundus photography, fluorescein angiography, haemodynamic measurements with laser Doppler flowmetry (LDF), laser interferometry and ocular blood flow (OBF) tonometry (baseline and 1, 2, 6 and 8 weeks after treatment).

MAIN OUTCOME MEASURES

choroidal blood flow (CHBF), fundus pulsation amplitude (FPA), pulsatile ocular blood flow (POBF), visual acuity. Changes smaller than 20% were considered clinically irrelevant.

RESULTS

Ocular haemodynamic parameters did not change significantly in the follow-up period. Changes of haemodynamic parameters showed no correlation to treatment spot, morphological changes or visual acuity. Changes of visual acuity were comparable to results of earlier studies.

CONCLUSION

Single treatment with PDT did not modify ocular blood flow parameters above 20% as assessed with different non-invasive methods.

Focal macular electroretinograms after photodynamic therapy combined with posterior juxtascleral triamcinolone acetonide

PURPOSE

Retinal function is commonly depressed transiently after photodynamic therapy (PDT). Additional treatment may prevent this impaired retinal function. The purpose of this study was to determine the changes in the focal macular electroretinograms (FMERGs) after PDT combined with TA for age-related macular degeneration.

METHODS

Thirty-four eyes that were successfully treated by PDT with a posterior juxtascleral injection of TA were studied. FMERGs, optical coherence tomography, and indocyanine green angiography were performed before and after the PDT.

RESULTS

The mean amplitudes of the FMERGs were not significantly decreased 1 week after PDT with TA (P > 0.05). The mean ratio of the FMERG b-wave 1 week after PDT to that before PDT was 1.09, with an indistinct hypofluorescence at the site of the PDT (18 eyes), and the ratio was 0.91 in the eyes with a distinct hypofluorescence border (16 eyes; P < 0.05).

CONCLUSION

The combined use of TA with PDT mitigated the depression of retinal function soon after PDT. However, there were cases of severe choroidal hypoperfusion corresponding to the site of the laser spot that impaired retinal function in comparison to cases with mild hypoperfusion. Even with severe choroidal hypoperfusion, the deterioration in retinal function was relatively mild, with the b-wave FMERG reduced by only 10%.

Serous retinal detachment following combined photodynamic therapy and intravitreal bevacizumab injection

We report a case of serous retinal detachment following combined photodynamic therapy (PDT) and intravitreal bevacizumab injection in subfoveal choroidal neovascularization (CNV).

A 53-year-old woman was diagnosed with subfoveal CNV secondary to age-related macular degeneration (AMD) and treated with combined PDT and intravitreal bevacizumab injection. One day after treatment, the patient experienced a sudden decline of vision and optical coherence tomography (OCT) showed serous retinal detachment involving the macula. She was managed conservatively with an oral steroid beginning on the second day of the combined treatment and the subretinal fluid started to decrease one week following the initiation of steroids.

This case suggests that combined PDT and intravitreal injection of bevacizumab can be associated with serous retinal detachment. Additional studies are needed to establish the safety and complications following this treatment regimen.

Indocyanine green angiography in eyes with substantially increased subretinal fluid 1 week after photodynamic therapy

PURPOSE

To investigate the characteristics of eyes in which a serous retinal detachment became substantially more extensive and persisted 1 week after photodynamic therapy (PDT) using indocyanine green (ICG) angiography.

DESIGN

Retrospective, interventional case series.

PATIENTS AND METHODS

The authors reviewed the ICG angiograms of five eyes of five patients with neovascular age-related macular degeneration.

RESULTS

In all eyes, the ICG angiograms obtained 1 week after PDT showed a well-demarcated hypofluorescent area corresponding to the treatment spot. Vascular hyperpermeability emanating from the middle and large choroidal vessels was seen within the hypofluorescent area whether the targeted choroidal neovascularization was perfused or not.

CONCLUSIONS

Choroidal vascular hyperpermeability on ICG angiography is a common finding in eyes with substantially increased subretinal fluid 1 week after PDT. PDT might even affect the middle and large choroidal vessels within the treatment spots under some conditions, leading to a supply of subretinal fluid and causing a persistent serous retinal detachment.

Ocular Photodynamic Therapy – Standard Applications and New Indications (Part 2)

Photodynamic therapy (PDT) has become a well-established treatment for vascular forms of age-related macular degeneration (AMD). The implementation of evidence-based medicine principles into the treatment regimen of AMD seems to be immensly important, since AMD continues to be the most frequent cause of blindness among patients older than 65 years in industrialized countries. Numerous randomized prospective studies demonstrated high levels of evidence for the efficacy of various treatment approaches such as laser photocoagulation, PDT, subretinal surgery or novel anti-angiogenic drugs [Arch Ophthalmol 2006;124:597-599]. The high evidence shown by these studies supported the rationale to use PDT also in additional, less frequent, vasoproliferative diseases. Although these 'case series' and 'individual case control studies' have a low level of evidence, they give us important information for treatment decisions in these rare conditions. The goal of this survey is to review the current literature regarding PDT in vasoproliferative and exudative ocular diseases outside AMD. Many studies modified the treatment parameters of PDT to address the specific pathology of the underlying disease. Table 1 summarizes the diseases and treatment parameters that are described in this part 2, the entire table of this review is included in part 1 (www.karger.com/doi/10.1159/ 000101922).

Prolongation of choroidal hypofluorescence following combined verteporfin photodynamic therapy and intravitreal triamcinolone acetonide injection

PURPOSE

To determine the incidence and effect of persistent/prolonged choroidal hypofluorescence (PCH) following combined verteporfin photodynamic therapy and intravitreal triamcinolone acetate injection (PDT + IVTA) for age-related subfoveal choroidal neovascularization (CNVM).

METHOD

A retrospective review of all patients undergoing PDT + IVTA for CNVM from December 2003 through November 2004 was performed. Included patients underwent intravenous fundus fluorescein angiography (FA) preoperatively and 1 week and 3 months following PDT. FA presence of persistent choroidal hypofluorescence (PCH) 3 months postoperatively was graded in each eye by comparison with the 1 week postoperative FA. Twenty-seven eyes treated with PDT alone before December 2003 served as controls.

RESULTS

A total of 53 eyes of 46 patients were identified for study. At 3 months post treatment, PCH was noted in 37/53 eyes (70%) receiving PDT + IVTA combination therapy compared to only 3/27 (11%) control eyes treated with PDT alone (P<0.0001; Fisher two-tailed exact test).

CONCLUSION

The findings suggest that IVTA prolongs the native PDT effect manifest by post treatment FA CH. This phenomenon may reflect a mechanism by which IVTA enhances the effectiveness of PDT. Further study is necessary to confirm and elucidate this possible association.

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.

Central retinal sensitivity measured with the micro perimeter 1 after photodynamic therapy for polypoidal choroidal vasculopathy

PURPOSE

To evaluate central retinal sensitivity and its relation to the symptomatic change noted in central visual disturbance shortly after photodynamic therapy (PDT) in eyes with polypoidal choroidal vasculopathy (PCV).

DESIGN

Retrospective interventional case series.

METHODS

We reviewed retrospectively 20 eyes of 20 patients who underwent PDT for the treatment of subfoveal PCV. Microperimetry in the macular area was performed with Micro Perimeter 1 (MP1) [Nidek, Vigonza, Italy] before and at one, three, and six months after PDT. Forty measurement points were located within the central 10 degree of the macula.

RESULTS

After PDT, although most eyes showed a reduction in exudation, the mean posttreatment visual acuity did not change significantly. At one month after PDT, however, retinal sensitivities within the central 2 degree, 6 degree, and 10 degree fields, which were 3.6 +/- 3.1, 5.1 +/- 3.4, and 6.2 +/- 3.6 dB [decibels] at baseline, improved to 5.9 +/- 3.8 (P = .003), 7.1 +/- 3.6 (P = .003), and 8.1 +/- 3.5 dB (P = .004). At one month after treatment, 14 patients (70%) noted subjective improvement of the central visual disturbance and mean retinal sensitivity within the central 2 degree, 6 degree, and 10 degree fields had improved more than 2 dB in 11, 10, and eight eyes, respectively. At three and six months after PDT, however, postoperative improvement of the retinal sensitivities was diminished.

CONCLUSIONS

Retinal sensitivity in the macular area of eyes with subfoveal PCV improved shortly after PDT, and may account, at least in part, for the immediate subjective improvement in central vision after PDT.

Optical coherence tomography on autologous translocation of choroid and retinal pigment epithelium in age-related macular degeneration

PURPOSE

To analyse structural changes after autologous translocation of choroid and retinal pigment epithelium (RPE) in patients with age-related macular degeneration (AMD) using optical coherence tomography (OCT).

METHODS

We performed a prospective nonrandomised study in 29 consecutive patients, who underwent submacular surgery with translocation of an autologous full-thickness graft of RPE, Bruch's membrane, and choroid. All patients had recent loss of reading vision due to AMD. OCT was performed before surgery and at 3- and 6- month follow-up to analyse the morphological appearance of the graft and the overlying retina.

RESULTS

Maximum retinal thickness decreased from mean 408 microm (standard deviation (SD) 127 microm) preoperative to mean 373 microm (SD 104 microm) at 6-month follow-up (P=0.094). In 11 cases (40%), a nearly physiological shape of the retina was seen at this time point. A macular hole persisted in two eyes after silicone oil removal. In most eyes, the highly reflective band of the graft presumably corresponding to RPE was continuous with the surrounding RPE band in all six OCT scans. Eyes with flat appearance of the graft at 6-month follow-up (<300 microm) showed a significantly better functional outcome than eyes with more prominent grafts. Interestingly, most patients did not complain about metamorphopsia, even though the graft was prominent or wrinkled in some cases.

CONCLUSION

OCT is a useful tool in monitoring intra- and subretinal changes after subretinal surgery with graft translocation. We demonstrated that graft translocation may lead to a normalisation of retinal thickness and stabilisation of visual acuity.

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.

Large submacular hemorrhage following PDT with verteporfin in patients with occult CNVM secondary to age-related macular degeneration

A review of the charts for all patients who developed large submacular hemorrhages following photodynamic therapy for choroidal neovascular membranes secondary to age-related macular degeneration yielded three patients who met the criteria for a large submacular hemorrhage. All three patients were treated for exudative age-related macular degeneration and were taking warfarin for chronic anticoagulation. Before photodynamic therapy, the international normalized ratio ranged from 1.2 to 1.6. All three patients had received at least one previous verteporfin treatment in the study eye. All three hemorrhages were not noted immediately after photodynamic therapy and were documented within 1 to 2 weeks following the procedure. Patients with age-related macular degeneration who are receiving warfarin therapy and undergoing repeat verteporfin treatments appear to be at risk for submacular hemorrhages.

Application of the Standard Photodynamic Treatment Protocol for Symptomatic Circumscribed Choroidal Hemangioma

PURPOSE

To describe the results of photodynamic therapy (PDT) using a standard protocol, developed for treating choroidal neovascularization (CNV), for the treatment of circumscribed choroidal hemangioma (CCH).

METHODS

A prospective, uncontrolled, consecutive case series of patients with symptomatic CCH that were treated using the standard PDT protocol was evaluated periodically with ophthalmic exams and echography.

RESULTS

Nine CCH patients were included in the study. Mean tumor height decreased from 2.7 mm before treatment to 0.8 mm at the end of the follow-up period. Mean visual acuity improved from 6/15 to 6/12. Six patients required one PDT session, two patients two sessions, and one patient three sessions. Side effects included transient visual disturbances in two patients. One patient, who concomitantly presented with age-related macular degeneration, developed CNV.

CONCLUSIONS

The standard PDT protocol is effective for the treatment of CCH. Complications are uncommon. Further studies should assess the optimal PDT protocol for the treatment of CCH.

Combination therapy using aspirin-enhanced photodynamic selective drug delivery

In photodynamic therapy (PDT), excitation of a drug by light leads to a cascade of biochemical processes that can cause closure of blood vessels. It has been observed clinically that significant short-term leakage from the irradiated vasculature can occur prior to vessel closure and blood flow stasis. In this paper we demonstrate in a chicken embryo model that this leakage can be significantly enhanced by the presence of the cyclo-oxygenase inhibitor, aspirin. We also observe that following this aspirin-enhanced leakage, blood vessels close as effectively as after PDT in the absence of aspirin. Consequently we propose that this PDT-induced aspirin-enhanced leakage can be used to locally deliver a drug for combination therapy. This is then demonstrated in the chicken embryo using Visudyne as a PDT agent in combination with aspirin and fluorescein isothiocyanate dextran 10 kDa as leakage indicator. The latter represents a hypothetical drug to be delivered in various kinds of combination therapy. Two examples of this procedure would be the photodynamic treatment of choroidal neovasculature associated with exudative age-related macular degeneracy (AMD) where local delivery of an anti-angiogenic or an anti-inflammatory drug has been shown to be effective, or PDT of cancer where local dosing of a chemotherapeutic drug may well increase the treatment efficacy.

OPTICAL COHERENCE TOMOGRAPHY AFTER PHOTODYNAMIC THERAPY FOR PATIENTS WITH PATHOLOGIC MYOPIA

PURPOSE

To evaluate early changes after photodynamic therapy (PDT) for patients with subfoveal choroidal neovascularization (CNV) due to pathologic myopia by optical coherence tomography (OCT).

METHODS

PDT was performed on 10 eyes of 10 patients who presented with subfoveal CNV due to pathologic myopia. OCT was used to evaluate changes 1 day, 3 days, and 7 days after therapy. Changes in intraretinal and subretinal fluid and CNV were examined on the images obtained. The retinal elevation and the height of the neurosensory retinal detachment were calculated. From these two values, the thickness of the neurosensory retina was obtained. The thickness of the neurosensory retina was measured to ascertain the intraretinal fluid change, and the height of the neurosensory retinal detachment was measured to ascertain the subretinal fluid change.

RESULTS

The mean pretherapy retinal elevation+/-SD increased from 211+/-28 microm to 230+/-39 microm 1 day after PDT and decreased to 221+/-36 microm 3 days after therapy. At 7 days after therapy, the mean retinal elevation+/-SD was 211+/-22 microm. The retinal elevation was due to a subretinal fluid accumulation, whereas the thickness of the neurosensory retina increased only to a minor extent (range, 0-22 microm) and the foveal architecture remained unchanged. The mean pretherapy height+/-SD of the neurosensory retinal detachment was 6+/-11 microm. It was 18+/-20 microm, 12+/-12 microm, and 3+/-6 microm 1 day, 3 days, and 7 days after therapy, respectively. No change in CNV was observed during follow-up.

CONCLUSION

The results of our study indicate that the acute infiltration observed in patients with pathologic myopia after PDT occurs in the first day and regresses during the first week. Yet, it should be noted that, unlike in patients with age-related macular degeneration, the acute infiltration phase can be observed by OCT only to a limited extent.

Different transitions of multifocal electroretinogram recordings between patients with age-related macular degeneration and polypoidal choroidal vasculopathy after photodynamic therapy

AIM

To compare and evaluate the transitions in retinal function after photodynamic therapy (PDT) between age-related macular degeneration (AMD) and polypoidal choroidal vasculopathy (PCV) using multifocal electroretinograms (mfERGs).

METHODS

10 eyes with choroidal neovascularisation (CNV) secondary to AMD and 11 eyes with CNV secondary to PCV were included in the study. mfERGs were recorded before PDT, and 1 week and 3 months after PDT. mfERG recordings were acquired by a Veris system (V.3.1.3) using a 103 hexagon stimulus. The first-order kernel was used to calculate amplitudes and latencies. Mean amplitudes and latencies from two central rings rated 0-4 degrees of visual angle were analysed and compared with each disease.

RESULTS

In AMD, the mean first negative peak (N1) amplitudes tended to decrease, and the mean first positive peak (N1P1) amplitudes reduced to significant levels (p = 0.047) 1 week after PDT. 3 months after PDT, there were no significant differences in the mean N1 and N1P1 amplitudes compared with pre-PDT values. In PCV, there were no significant changes in the mean N1 and N1P1 amplitudes 1 week after treatment. However, 3 months after PDT, mean amplitudes showed significant increases in N1 (p = 0.008) and N1P1 (p = 0.006) amplitudes compared with pre-PDT values.

CONCLUSIONS

mfERG recording transitions are different between patients with AMD and those with PCV. In patients with AMD, these results may show transient impairments in retinal function 1 week after PDT, but in those with PCV, the efficacy of PDT is superior to the impairment after PDT.

Preclinical evaluation of a novel water-soluble chlorin E6 derivative (BLC 1010) as photosensitizer for the closure of the neovessels

In the present study, photodynamic activity of a novel photosensitizer (PS), Chlorin e(6)-2.5 N-methyl-d-glucamine (BLC 1010), was evaluated using the chorioallantoic membrane (CAM) as an in vivo model. After intravenous (i.v.) injection of BLC 1010 into the CAM vasculature, the applicability of this drug for photodynamic therapy (PDT) was assessed in terms of fluorescence pharmacokinetics, i.e. leakage from the CAM vessels, and photothrombic activity. The influence of different PDT parameters including drug and light doses on the photodynamic activity of BLC 1010 has been investigated. It was found that, irrespective of drug dose, an identical continuous decrease in fluorescence contrast between the drug inside and outside the blood vessels was observed. The optimal treatment conditions leading to desired vascular damage were obtained by varying drug and light doses. Indeed, observable damage was achieved when irradiation was performed at light doses up to 5 J/cm(2) 1 min after i.v. injection of drug doses up to 0.5 mg/kg body weight(b.w.). However, when irradiation with light doses of more than 10 J/cm(2) was performed 1 min after injection of drug doses up to 2 mg/kg body weight, this led to occlusion of large blood vessels. It has been demonstrated that it is possible to obtain the desired vascular occlusion and stasis with BLC 1010 for different combinations of drug and/or light doses.

Retinal assessment using optical coherence tomography

Over the 15 years since the original description, optical coherence tomography (OCT) has become one of the key diagnostic technologies in the ophthalmic subspecialty areas of retinal diseases and glaucoma. The reason for the widespread adoption of this technology originates from at least two properties of the OCT results: on the one hand, the results are accessible to the non-specialist where microscopic retinal abnormalities are grossly and easily noticeable; on the other hand, results are reproducible and exceedingly quantitative in the hands of the specialist. However, as in any other imaging technique in ophthalmology, some artifacts are expected to occur. Understanding of the basic principles of image acquisition and data processing as well as recognition of OCT limitations are crucial issues to using this equipment with cleverness. Herein, we took a brief look in the past of OCT and have explained the key basic physical principles of this imaging technology. In addition, each of the several steps encompassing a third generation OCT evaluation of retinal tissues has been addressed in details. A comprehensive explanation about next generation OCT systems has also been provided and, to conclude, we have commented on the future directions of this exceptional technique.

Correlation of optical coherence tomography and fundus fluorescein angiography following photodynamic therapy for choroidal neovascular membranes

AIMS

To assess the correlation between optical coherence tomography (OCT) and leakage on fundus fluorescein angiography (FFA) following photodynamic therapy (PDT) with verteporfin for choroidal neovascularisation (CNV).

METHODS

Retrospective comparative observational case series of patients who were treated with PDT for CNV from one centre. All patients had 3 monthly FFA and OCT following initial PDT to assess if further treatment was required. A pair of FFA and OCT images from the same visit at a random follow up date were taken from each patient's series and assessed separately by different observers. The presence of pigment epithelial detachment, subretinal fluid, vitreomacular traction, intraretinal fluid, absence of foveal depression, and the retinal thickness on OCT were correlated with presence of leaks on FFA.

RESULTS

A total of 121 eyes of 121 patients were included. The presence of subretinal fluid, gross cystoid macular oedema, sponge-like retinal thickening and retinal thickness of more than 350 mum on OCT correlated well with leak on FFA (p value <0.01). The likelihood ratios were 3.0, 5.7, 2.7, and 3.6, respectively. The presence of a solitary foveal cyst did not correlate well with leaks on FFA.

CONCLUSIONS

The presence of subretinal fluid, intraretinal fluid in the form of gross cystoid macular oedema, or sponge-like retinal thickening, or a retinal thickness more than 350 mum correlates with leaks on FFA and so suggests the need for repeat PDT.

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.

Added value of OCT in evaluating the presence of leakage in patients with age-related macular degeneration treated with PDT

BACKGROUND

Evaluating the presence of leakage on fluorescein angiography (FA) in patients with age-related macular degeneration (AMD) retreated with photodynamic therapy (PDT) can be difficult. New diagnostic tools such as optical coherence tomography (OCT) might help to optimize PDT management.

METHODS

Thirty AMD patients scheduled for regular follow-up FA in conjunction with PDT treatment were also scanned with OCT. Follow-up data at 9 months were retrieved from the patients' medical records. Inter-observer agreement [kappa coefficient] for the presence of leakage on FA, for OCT parameters for leakage, and agreement between FA and OCT evaluations were calculated. The indication for retreatment was evaluated using the leakage analysis based on FA alone, OCT alone, and both examinations combined, and compared to the actual follow-up of the patients at 9 months.

RESULTS

Agreement between the two observers for the presence of leakage on FA was moderate (kappa=0.51). OCT agreement between the two observers for the presence of leakage was good (kappa=0.85). Agreement between FA and OCT for the presence of leakage was poor (kappa=0.16). Follow-up data at 9 months on all patients were analyzed. Seven out of 30 patients were not retreated at the time of examination, and four of these patients (57%) remained stable without further treatment. Twenty-three patients did receive a PDT treatment at the time of examination; and eight of these patients did not show leakage on OCT, and five of these patients (62%) remained stable without additional treatment. In contrast, only three out of 15 patients (20%) with leakage on both FA and OCT remained stable during this 9 month follow-up period.

CONCLUSIONS

Inter-observer agreement for the presence of leakage was moderate for FA and good for OCT. There was considerable disagreement between leakage as judged by OCT and by FA. OCT could be of help in the decision regarding PDT retreatment. Assuming that 57% of the patients without leakage either on FA or OCT would remain stable without retreatment, the rate of probable ineffective retreatment could be reduced from 35% to 20%.

Dynamics of Retinal Function after Multiple Photodynamic Therapies in Age-Related Macular Degeneration: A Report of Cases

PURPOSE

To monitor retinal function after multiple laser treatments by photodynamic therapy (PDT) with the multifocal electroretinogram (mfERG) in age-related macular degeneration (AMD).

METHODS

Five eyes of five subjects with AMD were investigated before the first and 1 month after each of three PDT treatments. Function was assessed using the cone- and rod-mediated mfERG, high-contrast distance visual acuity, central visual fields and contrast sensitivity. For each subject the local first-order mfERG results before treatment were used as a template and fitted against the local post-treatment results (Matlab, Mathworks).

RESULTS

We found transient reduction of the cone- and rod-mediated amplitudes between the first and second treatments but stable or improved mfERG function in four of five eyes for the cone-mediated mfERG and in all eyes for the rod-mediated mfERG after three treatments. Visual acuities and contrast sensitivities remained stable between treatments in four and two eyes respectively, whereas visual fields showed substantially higher mean defects in two subjects after all treatments.

CONCLUSION

As found in previous studies of the cone-mediated mfERG after one PDT treatment, objective function was stabilized after multiple treatments in this case report. Similarly, although poor at baseline, rod-mediated function was not further compromised. Transiently reduced amplitudes after 1 month possibly reflected choroidal hypoperfusion. A larger sample size is needed to confirm if additional evaluation using electrophysiological criteria might be helpful in re-treatment decisions during PDT.

Early optical coherence tomography changes after photodynamic therapy in patients with age-related macular degeneration

PURPOSE

To evaluate early changes after photodynamic therapy (PDT) in patients with age-related macular degeneration (AMD) by optical coherence tomography (OCT).

DESIGN

Prospective interventional case series.

METHODS

PDT was performed on 20 eyes of 20 patients who presented with subfoveal choroidal neovascularization (CNV) attributable to AMD. OCT was used to evaluate changes at 2, 12, and 24 hours and at 3, 7, 15, and 30 days after therapy.

RESULTS

In the first 24 hours, OCT showed an increase in the subretinal fluid (SF) in all eyes and an increase in intraretinal fluid (IF) in 13 eyes. On the 15th day and the 30th day after therapy, reduction of SF and IF was observed in almost all eyes.

CONCLUSIONS

Serial OCT evaluation of patients with subfoveal CNV attributable to AMD suggests that the initial response after PDT is an increase in SF and IF.

Optical coherence tomography to monitor photodynamic therapy in pathological myopia

AIM

To evaluate the role of optical coherence tomography (OCT) in determining choroidal neovascularisation (CNV) activity before and after photodynamic therapy (PDT) in patients with pathological myopia.

METHODS

33 patients (33 eyes) with pathological myopia and being treated with PDT were included. Every 3 months all patients were evaluated and presence or absence of leakage on fluorescein angiography, presence of intraretinal or subretinal fluid on OCT, and macular and choroidal neovascular complex thickness on OCT, were determined at each examination.

RESULTS

The macular thickness decreased significantly after PDT at 6 months (p = 0.001) and at 12 months follow up (p = 0.01). However, no significant changes in CNV thickness were measured after PDT at 6 months of follow up (p = 0.418) and at 12 months of follow up (p = 0.521). Once the diagnosis of CNV associated with pathological myopia was established, before treatment, OCT had a sensitivity of 96.96% for detecting CNV activity. After treatment, OCT had a good sensitivity (95.23%) and a moderate specificity (69,69%) in determining CNV activity, which resulted in a diagnostic efficiency (proportion of correct results) of 79.62%.

CONCLUSIONS

OCT appears to be useful for indicating CNV activity. Therefore, it may serve as a complementary technique for deciding the need for PDT and re-treatment in patients with pathological myopia.

Comparison of reduced and standard light application in photodynamic therapy of the eye in two rabbit models

BACKGROUND

Current PDT treatment for age-related macular degeneration uses a standard radiant exposure of 50 J/cm(2) at an irradiance of 600 mW/cm(2). However; there is a general problem with the unusually high irradiance; in fact, the rate of photochemical production of singlet oxygen may be limited by insufficiently oxygenized neovascular tissue. It was the aim of this study to evaluate the efficacy of verteporfin (Visudyne) photoactivation to induce thrombosis of choriocapillaries and in experimentally induced corneal neovascularizations in rabbits by varying irradiance and retinal radiant exposure.

MATERIALS AND METHODS

The light-dose threshold to induce micro-thrombosis in the choriocapillaries (seven eyes) and in corneal neovascularizations (eight eyes) of Chinchilla-Bastard rabbits using different retinal irradiances (100 and 600 mW/cm(2)) at different radiant exposures (20, 10, 5, 2.5, 1.25, 0.62, and 0.3 J/cm(2)) was evaluated. Induction of neovascularizations was performed 7 days prior to PDT treatment using intracorneal silk sutures. A dose of 2 mg/kg verteporfin was intravenously infused 10 min before standard PDT. The criterion for vascular thrombosis was vessel closure as determined by fluorescein angiography 1 h and 1 day post exposure.

RESULTS

Experiments on the choroid revealed vessel closure 1 h after irradiation at ED(50) = 10.8 J/cm(2) (both 600 and 100 mW/cm(2)) and after 24 h at ED(50) = 2.4 J/cm(2) (600 mW/cm(2)) versus 1.8 J/cm(2) (100 mW/cm(2)). Vessel closure was enhanced at irradiation with 100 mW/cm(2). Regarding corneal neovascularizations, vessel thrombosis was observable by dark appearance of irradiated clotted neovascular tissue and angiographically by a lack of leakage at ED(50) thresholds of 0.62 J/cm(2) (1 h) and 0.41 J/cm(2) (1 day) for 100 mW/cm(2) and of 0.99 J/cm(2) (1 h), and 0.67 J/cm(2) (1 day) for 600 mW/cm(2). Thus in both experiments thresholds for vessel closure were reduced by a factor of 1.5 for the lower intensity. Histology revealed more selective vessel occlusion without RPE and photoreceptor damage for 100 mW/cm(2) rather than 600 mW/cm(2) intensity at threshold irradiation.

CONCLUSION

Low-intensity PDT with verteporfin for neovascular tissue seems to be more effective than regular high-intensity PDT. Future preclinical trials should address the issue of proper dosimetry for effective PDT in age-related macular degeneration.

Effect of photodynamic therapy on the function of the outer blood-retinal barrier in an in vitro model

BACKGROUND

Photodynamic therapy (PDT) is a well established clinical treatment for age-related macular degeneration (AMD), and comprises intravenous injection of verteporfin and subsequent application of a non-thermal laser beam to the area of AMD to induce selective vascular occlusion. Since there is evidence that PDT may cause outer blood-retinal barrier (BRB) breakdown and possibly RPE cell alteration, we investigated the effect of PDT on the BRB function of the RPE in an in vitro model.

METHODS

Twenty-one monolayers of human RPE cells were cultured on semipermeable membranes until a stable barrier function was achieved as determined by transepithelial electrical resistance (TER) and sodium fluorescein permeability. To test the effect of PDT on the outer BRB function, non-thermal laser (692 nm), verteporfin or a combination of both were applied. TER assessment prior to and after PDT was utilized to identify changes in barrier function of the RPE in this in vitro model. Finally, monolayers of RPE cells were evaluated by transmission electron microscopy (TEM).

RESULTS

No significant TER decrease was observed after application of non-thermal laser alone or after administration of verteporfin in therapeutic concentrations, but combination of these modalities resulted in significantly decreased TER within 4 h. Except for intercellular blisters, no damage to the RPE was evident in TEM. Verteporfin added at concentrations higher than therapeutic doses (2 mg/ml) resulted in an immediate decrease in TER and damage to the RPE cells.

CONCLUSION

The combination of a therapeutic concentration of verteporfin and application of non-thermal laser resulted in a morphologically and functionally detectable breakdown of the outer BRB function of the RPE without any damage to the RPE cells themselves in vitro. However, increasing the concentration of verteporfin can result in RPE cell damage.