Improvement of visual acuity after photodynamic therapy for choroidal neovascularization in choroidal osteoma

Editor, Choroidal osteoma (CO) is a very unusual ossifying tumour of the choroid. It is typically found in healthy young women in the second or third decades of life (Shields et al. 1988). Although benign, this tumour may lead to severe visual loss by subretinal fluid and haemorrhage associated with choroidal neovascularization (CNV). We report a case of CNV associated with CO for which photodynamic therapy (PDT) permitted significant improvement in visual acuity (VA). A 15-year-old girl with a bilateral CO, diagnosed 10 years before at the age of 5 years, presented with a progressive decrease in the vision in her left eye of several months' duration, associated with metamorphopsia. The examination revealed VA at 20/20 with + 1 D sphere in the right eye and 20/200 with + 1.5 D sphere in the left eye. Anterior segments and intraocular pressures were normal. Fundus examination showed, in addition to CO, a small parafoveal haemorrhage on the left macula, suggesting the presence of a CNV. Optical coherence tomography (OCT), fluorescein and indocyanine green angiographies confirmed the presence of a classic CNV (Fig. 1). Given the poor VA and the localization of CNV, treatment by PDT was proposed. After a relevant discussion with the patient and her family, in particular about the pros (effectiveness and safety of PDT) and cons (absence of experience for this indication), the treatment by PDT was chosen and realized. One month later, the metamorphopsia had disappeared and VA in the left eye had improved to 20/25, reaching 20/20 2 months later. This functional improvement was correlated with a reduction in the size and the leakage of the CNV as shown by OCT and fluorescein angiography (Fig. 2). Six months after the PDT, VA was maintained at 20/20 in both eyes, and the treatment appeared to have had no adverse effects. Left eye before PDT. Fundus photograph (A) shows a choroidal osteoma with a small paramacular haemorrhage, suggesting the presence of CNV. Early (B) and late (C) stages of fluorescein angiography and OCT (D) confirmed the presence of choroidal neovascularization. Left eye 1 month after PDT. Fundus photograph (A) shows regression of the macular haemorrhage. Early (B) and late (C) stages of fluorescein angiography and OCT (D) demonstrate a significant decrease in the size of the CNV and a regression of the leakage. The beneficial role of PDT for CNV associated with age-related macular degeneration, pathological myopia, angioid streaks and trauma is well documented, but it has not yet been defined for CNV occurring in CO (Battaglia Parodi et al. 2001; Verteporfin Roundtable 2000 and 2001 Participants, TAP Study Group Principal Investigators, VIP Study Group Principal Investigators 2002; Browning 2003). An isolated case of CO treated by PDT for extrafoveal CNV was reported. It permitted closure of CNV, almost complete resolution of metamorphopsia and stabilization of VA (Battaglia Parodi et al. 2001). This encouraging report allowed us to propose PDT for our patient considering her poor VA, the location of CNV and the absence of any other alternative. The beneficial effect of PDT was evident not only by the improvement in VA and metamorphopsia but also by the objective reduction of CNV size on OCT and diminution of leakage on late stage fluorescein angiography. Photodynamic therapy might be an efficient and safe treatment for CNV associated with CO. Caution must be taken considering the lack of experience of PDT for this indication, and guidelines for using verteporfin in PDT should be followed (Verteporfin Roundtable 2000 and 2001 Participants, TAP Study Group Principal Investigators, VIP Study Group Principal Investigators 2002). Further studies are needed to evaluate the real success rate of this new treatment modality.