Theory of neutrinoless double-beta decay.

Neutrinoless double-beta decay, which is a very old and yet elusive process, is reviewed. Its observation will signal that the lepton number is not conserved and that the neutrinos are Majorana particles. More importantly it is our best hope for determining the absolute neutrino-mass scale at the level of a few tens of meV. To achieve the last goal certain hurdles must be overcome involving particle, nuclear and experimental physics. Nuclear physics is important for extracting useful information from the data. One must accurately evaluate the relevant nuclear matrix elements--a formidable task. To this end, we review the sophisticated nuclear structure approaches which have recently been developed, and which give confidence that the required nuclear matrix elements can be reliably calculated employing different methods: (a) the various versions of the quasiparticle random phase approximations, (b) the interacting boson model, (c) the energy density functional method and (d) the large basis interacting shell model. It is encouraging that, for the light neutrino-mass term at least, these vastly different approaches now give comparable results. From an experimental point of view it is challenging, since the life times are long and one has to fight against formidable backgrounds. One needs large isotopically enriched sources and detectors with high-energy resolution, low thresholds and very low background. If a signal is found, it will be a tremendous accomplishment. The real task then, of course, will be the extraction of the neutrino mass from the observations. This is not trivial, since current particle models predict the presence of many mechanisms other than the neutrino mass, which may contribute to or even dominate this process. In particular, we will consider the following processes: The neutrino induced, but neutrino-mass independent contribution. Heavy left and/or right-handed neutrino-mass contributions. Intermediate scalars (doubly charged, etc). Supersymmetric (SUSY) contributions. We will show that it is possible to disentangle the various mechanisms and unambiguously extract the important neutrino-mass scale, if all the signatures of the reaction are searched for in a sufficient number of nuclear isotopes.

Evolution of idiopathic epiretinal membrane studied by optical coherence tomography.

PURPOSE: To study the evolution of idiopathic epiretinal membrane (IERM) as examined by optical coherence tomography (OCT) in the 1-mm-diameter circle centered on the fovea. METHODS: In a case series study 71 subjects (71 eyes) with idiopathic epiretinal membrane and macular thickness greater than 220-/+10 micro m were evaluated by OCT. The fellow healthy eye of 52 patients was used as the control group. The mean follow-up was 36 months. Measurements of macular thickness at baseline and at the final examination were performed. Best-corrected visual acuity was expressed as the number of letters read on the Early Treatment Diabetic Retinopathy Study chart. RESULTS: Within the inner macular central circle of 1 mm diameter the thickness of the fovea increased by an average of 12.29% (p<0.001) during follow-up in the study group while in the control group the foveal thickness decreased by -0.44% (p=0.43). The mean increase of the fovea thickness was accompanied by a modest decrease of best-corrected visual acuity from a mean 43.26 letters at baseline to a mean 39.20 letters at the last examination (p<0.001). CONCLUSIONS: In the study group the macular thickness increased during a mean follow-up period of 36 months. The average increase between the baseline and the final examination at the inner central circle of 1 mm diameter was 12.29%. Decrease of the macular thickness was not observed in any of the studied cases. The mean decrease of visual acuity was 9.4%. OCT also depicted with accuracy the changing morphology of the affected macula during the study period.

Intravitreal bevacizumab for the treatment of feeder vessel of subfoveal choroidal neovascularization.

PURPOSE: To report in a single case the effectiveness of bevacizumab in the treatment of feeder vessels (FVs) of subfoveal choroidal neovascularization (CNV) secondary to age-related macular degeneration (AMD). METHODS: One patient received intravitreal bevacizumab (Avastin) (1.25 mg) which was repeated 4 weeks after the first intravitreal injection. Fluorescein angiography and optical coherence tomography (OCT) were performed. Visual acuity (VA) was also checked. RESULTS: Occlusion of the FVs was observed 4 weeks after starting treatment. During the follow-up period and in the final examination 13 months after the first injection, the FVs remained occluded. Complete resolution of macular edema and improvement of the VA were noticed after the second bevacizumab intravitreal injection. CONCLUSIONS: This report documents the successful occlusion of FVs of subfoveal neovascularization after two intravitreal bevacizumab injections in a patient who was followed up for 1 year after the occlusion. Further long-term investigation is warranted given the promising 12-month results.

[Ahmed valve in high-risk glaucoma surgery]. / La valve d'Ahmed dans la chirurgie des glaucomes "à haut risque".

We used the Ahmed valve for the treatment of 142 eyes with high-risk glaucoma. The glaucoma was neovascular in 74 cases, aphakic or pseudophakic in 19 eyes and occurred after previous faliure of filtering surgery in 49 eyes. Preoperative mean IOP was 31.6+/-10.4 mmHg under topical and/or systemic treatment. The success rate (IOP<22 mmHg with only topical treatment) was 56.3% with a mean follow-up of 32.4 months. Complications were fewer and milder compared with those reported for other types of drainage implants and for other types of antiglaucoma procedures.

Visual field improvement after treatment of optic disk pit maculopathy with the macular buckling procedure.

PURPOSE: To evaluate visual field changes in 18 of 21 patients with unilateral optic disk pit maculopathy who were successfully treated with the macular buckling procedure. METHODS: In this prospective study, visual field examination with the Humphrey analyzer (programs 30-2 and 10-2) was recorded before treatment, repeated 1 month after the operation, and repeated every 6 months thereafter. All 18 patients were treated with the macular buckling procedure. The operation consisted of fixation of a silastic sponge explant at the posterior pole corresponding to the macula. RESULTS: In 18 eyes included in the study and successfully treated, an improvement in visual field indices was recorded. The mean deviation improved from -7.75+/-3.15 (program 30-2) and -10.19+/-3.66 (program 10-2) decibels before surgery to -6.25+/-2.61 (P<0.0001) and -8.56+/-3.13 (P<0.0001) decibels at the last examination, respectively. No additional visual field defect was induced in any of the 18 eyes after treatment. Also, the majority of the eyes (16/18) gained from 1 to 7 Snellen lines of visual acuity (P<0.0001). CONCLUSION: Improvement of central and peripheral visual field (within 30 degrees of fixation) was recorded after the treatment of optic disk pit maculopathy with the macular buckling procedure. This technique seems to be effective for treatment of the disease with good anatomic and functional results.

Clinical evaluation of the effect of mitomycin-C in re-operation for primary open angle glaucoma.

The aim of the study was to evaluate the effect of mitomycin-C (MMC) in a second antiglaucoma operation after failure of the first operation. We assessed 46 patients (26 male, 20 female, mean age 64.2 years) with high intraocular pressure (IOP) (mean 32.4 +/- 5.2 mmHg) despite previous trabeculectomy (Tr-Ec) one to three years earlier and topical or systemic medical treatment. All patients underwent a second Tr-Ec and were randomly divided into two groups: group A, 24 patients, underwent a second Tr-Ec with MMC and group B, 22 patients, also underwent a second Tr-Ec but without MMC. Postoperative complications included: shallow anterior chamber (duration > 1 week), group A 29.2%, group B 13.6%; chroidal effusion, group A 8.3%, group B 0%; cystic degeneration of conjunctiva, group A 16.6%, group B 4.5%; transient maculopathy, group A 12.5%, group B 0%. IOP control (< or = 20 mmHg after 18 months) was: group A 20 patients (83.3%) with mean 12.5 +/- 3.2 mmHg and group B 13 patients (63.6%) with mean 19.6 +/- 6.1 mmHg. In conclusion, the use of MMC in re-operation for primary open-angle glaucoma is associated with a higher rate of and more severe postoperative complications than Tr-Ec alone. However, it achieves significantly lower IOP in a larger number of patients.

Risk factors in ocular hypertension.

The aim of the study was to determine whether certain factors are related to an increased risk of developing open-angle glaucoma. A total of 345 untreated glaucoma suspects with intraocular pressure (IOP) > or = 21 mmHg, cup to disc ratio 0.4 or less and no visual field defects, were followed up for 6 to 8 years (mean 7.3). During the follow-up 71 patients developed established glaucoma and were compared to the remaining 274 patients. The following factors were analysed: age, family history of glaucoma, IOP, Humphrey 30-2 visual fields, optic disc appearance, myopia, exfoliation, arterial hypertension and diabetes. Analysis yielded statistically significant results regarding a number of these factors in the patients who subsequently developed open-angle glaucoma. A significant association with the subsequent development of field loss in ocular hypertension (OHT) included: heredity (p < 0.001), age > or = 60 years (p = 0.013), axial myopia (0.001 < p < 0.01) and arterial hypertension (p = 0.05). About 20% of patients with ocular hypertension developed glaucoma over a period of seven years. Risk factors such as heredity, age, myopia and arterial hypertension, among others, must be considered in the follow-up of glaucoma suspects.

Use of argon laser photocoagulation in the treatment of recurrent trichiasis: long-term results.

We describe our technique and analyze the long-term results of the use of argon laser photocoagulation in the treatment of 92 eyes with recurrent trichiasis. In spite of an incidence of recurrences of 64.1% which had to undergo a new laser photocoagulation session, the final success rate of the method was impressive (91.3%). The number of misdirected cilia per lid seems to constitute an important factor which affects both the rate of recurrences and the success rate of the procedure.