PDT for AMD improves the patient’s quality of life

Although visual results are still poor, patients experience improved retinal sensitivity, better perception of colors and less visual field distortion.

ROME — Photodynamic therapy (PDT) is the most appropriate choice when dealing with subfoveal choroidal neovascularization (CNV) in age-related macular degeneration (AMD), according to Corrado Balacco Gabrieli, MD, head of the eye Clinic and Specialization School of Rome University “La Sapienza.”

“There is no surgical or radiation therapy that works for subfoveal CNV. Conventional laser therapy, which gives good results in extrafoveal or juxtafoveal CNV, has also proven totally ineffective. On the contrary, photodynamic therapy, when correctly applied, has something to offer. Although the gain of visual acuity is very scarce or none, there is a noticeable improvement of other functional parameters which improve the patient’s life and acceptance of his or her condition,” Prof. Balacco said.

The procedure

PDT for AMD improves the patient’s quality of life The University of Rome is one of the oldest in Italy, dating back to the Middle Ages. The department of ophthalmology, which became part of the medical school in 1870, is one of the leading centers in Europe for both research and clinical practice. The University Eye Clinic offers highly specialized diagnostic services, medical care and surgery in all branches of ophthalmology. Special units, such as the hereditary retinal degeneration department, the low-vision services and the social ophthalmology services, are the main centers in Italy for research and medical care in these fields, cooperating with analogous research centers abroad. Professor Corrado Balacco Gabrieli, MD, has been head of the department since 1994. His scientific publications encompass numerous branches of ophthalmology, including pharmacology, clinical studies, physiopathology, virology, genetics and biochemistry. Since that time, the department has intensified its teaching focus. University hospital units include outpatient facilities; hospital; low vision services, clinical and surgical retina division; Center for Treatment of Diabetic Retinopathy and Retinal Vascular Disorders; laser treatment; glaucoma unit; ocular ultrasonography; ocular histology and histopathology services; social ophthalmology services; electrophysiology; and an ophthalmic emergency unit.

The effectiveness of photodynamic therapy in AMD patients with subfoveal CNV was tested in a study carried out by Prof. Balacco at his University Eye Clinic. A total of 78 patients with both classic and occult CNV of linear dimension less than 5400 µm and distance from the papilla greater than 200 µm were included in the study. Exclusion criteria were ruptures of the retinal pigment epithelium, ocular diseases with severe visual loss, media opacities, hyper-sensitivity to light, porphyria, hepatitis and severe cardiovascular diseases. Patients receiving cancer treatment and patients who had undergone ocular surgery in the preceding 2 months also were excluded.

All patients received a complete ocular examination, including measurement of best corrected visual acuity, Fansworth test for chromatic sensitivity, Amsler test, computerized perimetry (HFA 10-2), fluorescein angiography (FA) and body surface area (BSA). Informed consent was signed before therapy.

“Patients were treated with a single dose of 6 mg/m² BSA of Visudyne (verteporfin for injection, QLT PhotoTherapeutics/CIBA Vision). We used a Becton Dickinson infusion pump with a set volume of 30 mL in 10 minutes. In the second stage of PDT, when the dye is photoactivated, the retina was exposed for 83 seconds to a nonthermal red light of 690 nm, emitted by a Visulas 690 (Zeiss) diode laser. The total quantity of light was 50 J/cm². Power density was 600 mW/cm². The spot laser size ranged between 500 and 5,400 µm, according to the size of CNV to be treated. CNV size was measured on the most recent FA, dating from no more than 7 days before. The larger linear dimension was considered, including blood, retinal pigment epithelium detachment and hypofluorescent areas; 500 µm are added at each side,” Prof. Balacco explained.

Follow-up examinations were conducted at 3, 6, 9 and 12 months.

Good functional results

“Up to now, studies have only presented an anatomic evaluation of the CNV lesion after photodynamic therapy. As an end point, they consider the non-aggravation of AMD and disappearance of the leakage on FA. Our study, however, also included a functional evaluation. We were interested in the patient’s point of view to evaluate both the negative effects of the disease and the positive clinical results obtained after PDT treatment. The examinations we performed were aimed at quantifying the functional problems reported by our AMD patients and evaluating their impact on everyday life,” Prof. Balacco said.

Only a modest, almost insignificant improvement (P=.006) of the minimal resolution angle logarithm was obtained, from 0.45±0.12 to 0.38±0.15. Therefore, as Prof. Balacco reported, there was no visual acuity improvement.

Computerized perimetry showed a statistically significant improvement (P=.37) of medium retinal sensitivity of the macula, from 22.7±3.12 to 28.13 ±2.72 dB.

The decrease of both chromatic aberration (P=.006) and distortion of Amsler grid (P=.049) after PDT were statistically significant.

“Our results are unfortunately only short-term,” Prof. Balacco said. “However, they indicate that even in presence of a very poor visual improvement, other functional parameters related to the quality of vision can be significantly improved. A reduced extension of the scotoma means that the patient can perceive the lineaments of people’s faces, and thanks to the improved mean retinal sensitivity he or she can have a better perception of facial nuances and expressions. Also, a reduced distortion of images improves orientation and sense of direction.”

One last consideration was made by Prof. Balacco on the social benefits of a therapy that reduces the effects and slows down the progression of AMD.

“The incidence of AMD is bound to be greater in the next few years, due to the increasing life expectancy. In Italy, where the mean age of population is already very high, the social costs of AMD are calculated in billions,” he said. “The average AMD patient is living on an old age pension, and is therefore in care of the national health service for all diagnostic examinations and treatments. Added to this are the costs of invalidity pensions and low-vision benefits. Additional burdens are carried by the patient’s family or community when the visual impairment is such as to hinder the possibility for an independent life. Therefore, an effective therapy for age-related macular degeneration should be one of our priority goals.”

For Your Information:

• Corrado Balacco Gabrieli, MD, is head of the Eye Clinic and Specialization School in Ophthalmology at the University “La Sapienza,” Rome. He can be reached at Università La Sapienza, Istituto di Oftalmologia, Viale del Policlinico 155, Roma, Italy; (39) 06-490296; fax: (39) 06-4457706. Ocular Surgery News could not confirm whether or not Dr. Gabrieli has a direct financial interest in any of the products mentioned in this article or if he is a paid consultant for any companies mentioned.