Promising visual improvement of cystoid macular oedema by hyperbaric oxygen therapy.

Sir, C ystoid macular oedema occurs as a frequent complication in diabetic retinopathy, retinal vein occlusions, uveitis and postoperatively in cataract surgery. In general, macular oedema is most prevalent in age-related macular degeneration (AMD) Ischaemia and/or inflammation may pathologically explain the development of macular oedema associated with these disorders. No effective, specific treatment by laser, systemic or topical steroids, haemodilution or surgery is available. Hyperbaric oxygen (HBO) treatment has been used in extraocular ischaemic disorders. The hypothesis of hypoxia as a predominant cause of cystoid macular oedema prompted us to start HBO therapy in two patients with chronic macular cystoid oedema refractory to other treatment modalities. Therefore, we present here these two patients, each of whom experienced longlasting visual improvement after HBO. The first patient was a 57-year-old man with type 2 diabetes, with diabetic onset in 1998. He had suffered the complication of preproliferative retinopathy and severe cystoid maculopathy for 6months prior to presentation. His visual acuity (VA) was 0.5 and he had pronounced metamorphopsia and reading disability. He had a stabilized glycaemic metabolism and normal blood pressure. The second patient was a 56-year-old man with cystoid maculopathy complicated with idiopathic juxtafoveal retinal telangiectasis (group 1A) on the right eye, with VA 0.2 excentric, paracentral scotoma and reading blindness. The patient had a well treated arterial hypertension. Both patients were given a series of five HBO treatments of pure oxygen for 90min at a pressure of 2.4 bars absolute in a pressure chamber. Before and after the daily HBO treatment, each patient was tested for visual function by Amsler chart, reading ability and VA (Snellen chart). They also underwent an ophthalmological examination which included testing of the central visual field, biomicroscopy of the anterior eye segment, assessing intraocular pressure, direct and indirect ophthalmoscopy, fundus colour photography, fluorescein angiography (FA) and ocular coherence tomography (OCT). The diabetes patient improved increasingly during the treatment sessions, both subjectively and objectively, as shown in Fig. 1. Visual acuity in the right eye improved from 0.5 to 1.0, he achieved normal reading vision and metamorphopsia disappeared. Followup at 8months showed the improvements to be unchanged. The second patient experienced visual improvement after 3 days, with VA improving from 0.2 to > 0.9, normal reading vision and no metamorphopsia. Fluorescein angiography and