Photodynamic therapy in combination with intravitreal triamcinolone for myopic choroidal neovascularization

Abstract

Editor, Photodynamic therapy (PDT) using verteporfin has been shown to be an effective treatment of subfoveal choroidal neovascularization (CNV) due to age-related macular degeneration (AMD) and pathologic myopia. However, recent studies have suggested that PDT can induce collateral damage, especially to the choriocapillary layer (CCL) and retinal pigment epithelium (RPE), and that it paradoxically has angiogenic properties itself (Ruiz-Moreno & Montero 2003; Schmidt-Erfurth et al. 2003; Gelisken et al. 2004; Postelmans et al. 2004). In pathologic myopia, CCL and RPE may show progressive atrophy even without the presence of CNV. Therefore, especially in PDT of CNV due to pathologic myopia, the number of PDT sessions should be as few as possible. Intravitreal injections of triamcinolone acetonide (IVTA) have been shown to have angiostatic and antiexudative effects (Gillies et al. 2003; Jonas et al. 2003), and preliminary studies in AMD patients suggest that the combination of PDT and IVTA may reduce the number of PDT sessions necessary to occlude the neovascular complex and may be beneficial for patients who do not respond to PDT in the first sessions (Spaide et al. 2003; Rechtman et al. 2004). Theoretically, a combination of PDT and IVTA may be particularly advantageous in the treatment of myopic CNV, but this has not yet been reported. We report on a 35-year-old man with an anisometropic myopia (right eye − 4.5 D, left eye −17.0 D), who experienced the onset of metamorphopsia and a loss of visual acuity (VA) in the left eye from 0.7 to 0.3 due to subfoveal classic CNV (greatest linear dimension 600 µm). Visual acuity in the right eye was 1.0. He received PDT using verteporfin, which led to a rapid reduction of metamorphopsia and a slight increase in VA to 0.4. About 4 weeks later metamorphopsia recurred and VA dropped again. Fluorescein angiography showed reperfusion and leakage of the CNV. Altogether the subject received five PDT sessions at 10–12-week intervals with early postoperative temporary occlusion of the CNV, reduced metamorphopsia and VA increase, which were then followed by reperfusion of the CNV, increasing metamorphopsia and decreasing VA. During follow-up, ophthalmoscopy and fluorescein angiography revealed an increasing atrophy of the RPE and CCL, corresponding in size and shape to the PDT treatment spots. Visual acuity decreased to 0.08. At last, after giving informed consent, the patient received a sixth PDT session (at which point the greatest linear dimension of the CNV was 1800 µm), which was combined with an intravitreal injection of about 20 mg triamcinolone acetonide. The intravitreal injection was performed 2 weeks prior to the PDT; the injection technique has been described previously (Jonas et al. 2003). Over the 8 months since this last intervention, VA has stabilized at 0.125 in the absence of metamorphospia. Fluorescein angiography has shown staining of the lesion and a surrounding RPE window defect. Ophthalmoscopically and in optical coherence tomography no subretinal fluid has been detected. The lens shows signs of early posterior subcapsular cataract development. At present, PDT is the therapy of choice for subfoveal classic CNV due to myopia. However, its biological effects (Schmidt-Erfurth et al. 2003) may induce a lesion reperfusion and growth, and additional damage to the RPE and CCL may occur with increasing numbers of PDT sessions. Highly myopic patients are especially susceptible to this PDT-induced damage, which may override the beneficial effects of the treatment in either the short or the longterm. The present case report suggests that a combination therapy of PDT plus IVTA may be beneficial in myopic patients who do not respond to PDT alone. Furthermore, it suggests that the side-effects of PDT (in terms of the temporary increase in the expression of angiogenic growth factors and collateral damage to the RPE) may be reduced, and as a corollary, the number of re-treatments may be decreased by combining PDT with intravitreal triamcinolone acetonide. The possible benefits of a combination therapy may outweigh the risks of IVTA. Further studies are warranted.