Evaluation of fixation stability using different targets with the MP1 microperimeter.

The aim of this study was to evaluate fixation stability using two different fixation targets with the Nidek MP1 microperimeter. Twenty-nine healthy subjects with a mean age of 26.53 ± 7.35 years and visual acuity ≥0.0 logMAR were enrolled in this study. Fifty-eight eyes of 29 patients without ophthalmic and/or systemic disease underwent a fixation test with the MP1 microperimeter. Fixation stability related to a red cross (central) and/or a red circle (pericentral) target was quantified using either Fujii classification or by calculating the bivariate contour ellipse area (BCEA). For statistical analysis, BCEA values were converted into their logarithms (logBCEA) and all data obtained were analyzed using paired Student's t test. The inclination values of the axis of BCEA were analyzed with Chi squared test. The mean values of logBCEA and the mean values of the major and minor axis of the ellipses related to the cross and the circle fixation target were significantly different (68.2 %, p = 0.00; 95.4 %, p = 0.00; 99.6 %, p = 0.00, respectively) for each BCEA standard deviation. Fixation was significantly less stable for the pericentral fixation target in normal subjects, indicating an advantage for central fixation targets. These results are of particular interest when evaluation of changes in fixation is needed.

Effect of antidenaturant drugs on lysozyme deposit formation on soft contact lenses by liquid chromatography--electrochemical detection.

The effect of some antidenaturant drugs on the formation of lysozyme deposits on soft contact lenses was investigated by in vitro experiments. Results were obtained which encourage the use of this strategy to reduce lens spoilage. At the same time emphasis is given to the possibility that some functionalities (i.e. lysine groups) present in drug molecules could promote protein adsorption. In order to evaluate at a quantitative level the effectiveness of the drugs used to minimize the formation of deposits on soft contact lenses, a selective method for the determination of adsorbed lysozyme was developed. It is based on the hydrolysis of the 'lens/adsorbed lysozyme' system, followed by high performance liquid chromatography coupled to electrochemical detection of the released tryptophan residues. The lysozyme calibration curve was linear up to 5 mg ml-1 and the detection limit was 5 ng injected.

N omega-nitro-L-arginine methyl ester prevents apoptosis induced in the lateral geniculate nucleus by light deprivation in adult rabbit.

Exposure of adult rabbits to darkness for 48 h produces bilateral DNA fragmentation in the lateral geniculate nucleus as revealed in brain sections by terminal deoxynucleotidyl transferase (TdT)-mediated dUTP-biotin nick end labelling (TUNEL) technique, suggesting an apoptotic type of cell death. In agreement with the latter deduction, light microscopy assessment of the morphological characteristics showed marginalization and condensation of nuclear chromatin, typical features of apoptosis. These effects were abolished by systemic administration of N omega-nitro-L-arginine methyl ester, an inhibitor of nitric oxide (NO) synthesis, whereas the D isomer was ineffective. In conclusion, the present data demonstrate that light deprivation for 48 h produces apoptosis in the lateral geniculate nucleus of rabbit and suggest that NO might be involved.

N-methyl-D-aspartate (NMDA) and non-NMDA glutamate receptor antagonists protect from apoptosis induced in the lateral geniculate nucleus of rabbits exposed to the dark.

Mono or binocular deprivation, during early postnatal development, produces dramatic effects on the anatomy and physiology of the visual system. Here we report that dark exposure induces apoptotic cell death in the lateral geniculate nucleus (LGN) of adult rabbit and this may be related to activation of N-methyl-D-aspartate (NMDA) and non-NMDA subtypes of glutamate receptors. In situ DNA fragmentation (TUNEL) was observed in the LGN of rabbits exposed to dark for 48 h. Morphological changes were confirmed on hematoxylin-eosin stained brain tissue coronal sections. Systemic treatment with CGP 040116 or MK 801, two NMDA receptor antagonists, and with GYKI 52466, a non-NMDA receptor antagonist, prevented in situ DNA fragmentation and nuclear chromatin marginalization and condensation. In no instance was apoptosis seen in rabbits kept under a normal light-dark cycle. Our findings indicate that glutamate, acting on NMDA and non-NMDA receptors, may be involved in the mechanisms of apoptotic cell death induced in the LGN of adult rabbits exposed to darkness.

Direct demonstration of dopamine D1-like receptor sites in the ciliary body of the rabbit eye by light microscope autoradiography.

The pharmacological characteristics and the anatomical localization of [3H]-SCH 23390 in sections of the ciliary body of the rabbit eye were analyzed using a radioreceptor assay and autoradiographic techniques. [3H]-SCH 23390 was bound to sections of rabbit ciliary body in a manner consistent with the labelling of D1-like receptor sites. The dissociation constant (Kd) was 0.62 nmol/l, while the maximum binding capacity (Bmax) was 117 +/- 9 fmol/mg tissue. Light microscope autoradiography revealed [3H]-SCH 23390 binding sites within the epithelium of the ciliary processes, which is the ocular structure involved in the secretion of aqueous humor. No specific accumulation of silver grains was noticeable within the iridocorneal angle, which is the structure involved in the outflow of aqueous humor. These findings suggest that the rise in intraocular pressure caused by D1 receptor agonists is probably mediated by an increase of aqueous humor formation rather than by an inhibition of the outflow of aqueous humor.

Standardized measurement of visual acuity.

The authors reviewed the main aspects of visual acuity evaluation such as the characteristics of the test devices, the notation employed in recording the visual acuity level and the procedures for V.A. assessment, in both distance and near tests. In addition, new ten-letter charts, that tend to follow strictly the standardization guideline suggested by NAS-NRC, are described.

Prevalence of glaucoma in Ponza, Italy: a comparison with other studies.

The purpose of this study was to determine the prevalence of glaucoma in Ponza, Italy. The design was a population-based prevalence survey of residents of Ponza aged 40 years or older. There were 1,296 official residents identified by a house-to-house census, of whom 1,226 were identified as eligible for the study. Of these, 1,034 individuals (449 males and 585 females), or 84.3% of the eligible population, participated in the ophthalmological examination. A two-stage method was adopted to identify cases of glaucoma. All subjects underwent a standardized initial examination. Glaucoma suspects and 50% of non-suspects were referred to a definitive examination which included visual field testing. Patients were defined as glaucoma cases if they presented abnormal visual fields and at least one of the following: high 10P, large or asymmetric cup-to-disc ratio. In addition to typical glaucomatous visual field defects such as paracentral scotoma, nasal step, arcuate scotoma and temporal and/or central islands fields, a visual field defect was identified as a decrease in sensitivity greater than 6 db in at least one location of the central 10 degrees, two locations of the central 20 degrees or three locations of the central 30 degrees. Prevalence rates of 2.51% of Primary Open Angle Glaucoma (1.72%-3.66%, CI 95%), 0.97% of Primary Closed Angle Glaucoma (0.53%-1.77%, CI 95%) and 0.29% of secondary glaucoma were found. Moreover, 2.13% of probable POAG (1.41%-3.20%, CI 95%) and 6.00% of High Intraocular Pressure (4.71%-7.61%, CI 95%) were found. The prevalence rates of POAG found in the Ponza Ophthalmological Survey are consistent with the results of other studies. Minor differences are most likely due to the different criteria adopted in the assessment of glaucomatous visual field damage.

Prevalence and incidence of age-related cataract in a population sample from Priverno, Italy.

PURPOSE: To study the prevalence and incidence of age-related cataract in a random population sample from the town of Priverno in the Lazio Region, Italy. METHODS: In 1987, 860 people between the ages of 45 and 69 years, already participating in a study on cardiovascular risk factors, underwent an ophthalmological examination. Patients with lens opacities, assessed by a clinical biomicroscopy and a best-corrected VA equal to or worse than 0.2 LogMar (20/30), were defined as age-related cataract cases. Of the 828 patients without age-related cataract at the baseline, 602 were re-examined in 1994. The 7-year Cumulative Incidence was calculated in three ways, as follows: - referring to the baseline sample without age-related cataract; - referring to the follow-up sample without age-related cataract at baseline; and - adjusted for non-response to the follow-up. RESULTS: In the baseline sample, the prevalence of age-related cataract was 3.7% (2.7%-5.2%, 95% C.I.). Cumulative Incidence referring to the baseline sample was 6.5% (4. 8%-8.2%, 95% C.I.); Cumulative Incidence referring to the follow-up sample was 9.0% (6.7%-11.3%, 95% C.I.). Adjusted Cumulative Incidence of age-related cataract was 7.6% (5.6%-9.5%, 95% C.I.). CONCLUSIONS: The study suggests that, in the Priverno sample, aging, but not gender, is a very important risk factor for cataract. The authors conclude that more information is needed on incidence of age-related cataract needing surgical rehabilitation and on risk factors causing both progression of lens opacities and visual loss.

Multifaceted roles of nitric oxide in the lateral geniculate nucleus: from visual signal transduction to neuronal apoptosis.

The lateral geniculate nucleus (LGN) is the thalamic relay of retinal inputs to the visual cortex. It contains a rich array of brain terminals, which modulate the visual signals to the cortex. Several data have documented that beside cholinergic, GABA-nergic, istaminergic, serotoninergic, and glutamatergic signals, the LGN contains also fibers and interneurons expressing the enzyme that produces nitric oxide (NO). Here, we review the documented physiological roles of NO in the transmission of visual inputs to the cortex and in the processes of activity-dependent refinement of LGN connections. Moreover we focus on the recently suggested role of NO in processes of neurotoxicity in the LGN. Particular relevance is given to studies documenting that, through an excitotoxic cascade, NO triggers apoptosis in the LGN of new-born rats deprived of vision in one eye. Data are also discussed on a possible role of NO in the mechanisms of LGN neuronal loss induced by glaucoma. We believe that a better understanding of the role of NO in the LGN may contribute to discover new experimental strategies for the treatment of degenerative ophthalmic diseases.

Indocyanine green dye-enhanced micropulsed diode laser: a novel approach to subthreshold RPE treatment in a case of central serous chorioretinopathy.

PURPOSE: To present a case of central serous chorioretinopathy (CSC) treated with indocyanine green (ICG) dye-enhanced subthreshold micropulsed diode laser photocoagulation. METHODS CASE REPORT: A 35-year-old man presenting with recurrent CSC with persistent serous detachment of the sensory retina in his left eye who declined treatment with a 532 nm laser. Subthreshold treatment, with no visible endpoint, was performed with an 810 nm diode laser 15 minutes after the injection of 25 mg ICG in 2 cc of 5% glucose solution. The laser energy was delivered over the active leakage sites with a sequence of repeated 500 ms "envelopes" each containing a train of 250 micropulses with 500 mW peak power at 10% duty cycle (200 micros ON and 1,800 micros OFF) and each separated by 500 ms intra-envelopes relaxation time. Due to the absence of visible laser-induced lesions, post treatment ICG digital angiographic images were taken without further dye injection to verify that the hypofluorescent spots resulting from the subthreshold laser applications coincided with the points of leakage. RESULTS: After 7 days, the patient presented with a less hyperopic refraction, improved visual acuity, and reduction of serous neuroepithelial detachment. No signs of laser treatment were visible at fluorescein angiography. After 8 weeks, the serous neuroepithelial detachment was almost completely resolved. CONCLUSIONS: ICG dye-enhanced subthreshold micropulsed diode laser photocoagulation appears to be a safe and effective treatment and represents a possible approach for the management of chronic CSC with persistent central serous neuroepithelial detachment. Immediate post treatment ICG angiography, without ICG reinjection, allows documenting the actual number and location of the delivered subthreshold laser applications.

Apoptosis in the mechanisms of neuronal plasticity in the developing visual system.

Visual experience during early postnatal life is essential for normal development of synaptic connections in the visual system. In fact, altered visual experiences such as monocular deprivation (MD) or abnormal visual stimulation (e.g. strabismus, anisometropia) during this period disrupt the physiologic organization of the visual pathway, leading to loss of visual responses in cortical neurons and reduction in visual acuity of the affected eye, so that it becomes amblyopic. The authors review the main functional and morphologic changes induced by altered visual experiences in the developing visual system and focus on the recent discovery that MD induces apoptotic cell death in the lateral geniculate nucleus of newborn rats. Particular attention is given to the authors' studies documenting that, during development, MD leads retinal terminals to release excessive glutamate in the lateral geniculate nucleus where it elevates nitric oxide and causes DNA fragmentation. The latter event is known to activate poly-(ADP-ribose) polymerase, which in turn may trigger apoptosis. Better understanding of the mechanisms underlying the morphologic changes induced by altered visual experiences during development may open new venues for studying novel neuroprotective strategies for amblyopia and, more generally, for the treatment of ophthalmic diseases associated with neuronal apoptosis.

Acanthamoeba keratitis associated with contact lenses; report of three cases in Italy.

Three female patients, aged from 17 to 44 years, developed Acanthamoeba keratitis associated with the use of soft contact lenses and cosmetic contact lens. Two of these patients were myopic and wore soft contact lenses for optical purpose, while the third patient used a cosmetic lens. In this paper we describe the related risk factors, the success of cultural procedures and the outcome of medical management. In 2 out of the 3 cases we obtained cultures positive for Acanthamoeba, from the contact lenses and the contact-lens case. The isolated strains belong to the group II according to Pussard and Pons and they were proven pathogen for experimentally infected mice. All infections were treated successfully; however in 2 out of the 3 patients the visual acuity was reduced to the light perception.

Treatment of lacrimal stenoses obstructions with interventional radiology: immediate and 5-year follow-up results.

PURPOSE: This study was undertaken to evaluate the effectiveness of the Song stent in patients with nasolacrimal duct obstruction. MATERIALS AND METHODS: Between 2003 and 2007, we treated 76 consecutive nasolacrimal obstructions in 73 patients (mean age 56 years; range 19-81) with implantation of polyurethane stents. Indications were epiphora in 46 patients, dacryocystitis in 18 and recurrent conjunctivitis in three. Average follow-up was 1 year (3 months to 5 years). RESULTS: Technical success was achieved in 73 procedures (96%). Complications included pain in three cases, eyelid inflammation in four cases and severe bleeding in one case. Postprocedural mucocele was observed in five patients. Mean time without symptoms was 31 weeks. There were 24 cases of stent obstruction: 15 were treated with high-pressure 5% N-acetyl-cysteine and saline flush, achieving resolution in two cases; in three cases, attempts to recanalise the obstruction with a guidewire failed. The occluded stents were rsemoved in 22 patients: seven remained asymptomatic, 15 had recurrence of epiphora, nine received a new stent after dacryocystography and six underwent dacryocystorhinostomy. CONCLUSIONS: Advantages of the procedure include the lack of anatomical alterations to the lacrimal ducts and a low short-term complication rate, whereas limitations include restricted duration of stent patency. The pathophysiological causes of stent obstruction should be clarified in order to relate them to stent morphology.

Incidence of visual loss in the Ponza Eye Study, Italy.

AIM: To study the incidence of visual loss over a 12-year period in the survivors of an original cohort aged 40 years or older at baseline. METHODS: Visual acuity (VA) was measured by means of a standardized logMAR chart. World Health Organization definition of blindness and low vision was adopted (respectively, best-corrected VA >1.3 logMAR or a visual field <10 degrees around central fixation, and best-corrected VA >0.5-1.3 logMAR or a visual field <20 degrees around central fixation). Moreover, binocular visual loss incidence (VA>0.5 logMAR) was calculated in a 'healthy' group who had uncorrected VA of 0.0 logMAR or better in both eyes at baseline and absence of eye diseases. RESULTS: Of the 584 eligible survivors, 411 (70.7%) had a 12-year follow-up visit. The overall incidence figures were as follows: best-corrected binocular blindness (0.7%), binocular low vision (3.9%), monocular blindness (2.7%), and monocular low vision (5.0%), respectively. The results for presenting VAs were 1.2, 9.5, 4.2, and 15.3%. Figures for uncorrected, best-corrected, and presenting binocular visual loss incidence in the 'healthy' group were respectively 12.7, 0.9, and 3.7%. CONCLUSION: The discrepancy between the ideal and real situations that emerges from this study has important implications for health-care planning. Over a period of 12 years, a substantial percentage of 'healthy' subjects will have to seek medical care. Incident visual loss was caused mainly by untreated cataract, glaucoma, myopia, and age-related macular degeneration.

Introduction. Apoptosis and neuroprotection an exciting and rapidly expanding field of research in ophthalmology.

None.

The Italian support to prevention of blindness programmes in developing countries.

The authors point out that Italy, as a tradition, has always dedicated special attention to developing countries, due to its geographical position and its cultural background and that in 1971 the Italian Government has created by a law, as part of the Ministry of Foreign Affairs, the Department for Cooperation and Development, the objective of which is to contribute to the enhancement of the living conditions in developing countries. The authors report data on a Trachoma Control Project started in 1973 lasting to 1981, financially supported by the Ministry of Foreign Affairs and technically guided by some of the authors and point out that the major success of this Project is that, since they left the Country in 1981, trachoma control activities are still now carried out by using the same methodologies. Finally, the authors report data on a National Prevention of Blindness Programme, the extension of which will be guided in the near future by the Referral Center for Public Health Ophthalmology of Rome that has just prepared the plan of operation that foresees the reorganization and strengthening of the existing structures and manpower at the head quarter, tertiary, secondary and primary levels.

Retinal involvement in pigment dispersion syndrome.

Retinal involvement has been documented in a number of patients with pigment dispersion syndrome, which also appears to be associated with a higher than normal risk of retinal detachment. We studied 24 patients with this syndrome to determine the prevalence of lattice degeneration and other retinal disorders associated with a predisposition to detachment. Lattice degeneration was found in 8 of 24 patients examined, with a prevalence that is significantly higher than that reported for normal subjects. Four eyes presented areas of retinoschisis and only one displayed a rhegmatogenous detachment. A father and son (both myopes) were found to have similar lattice lesions in the same retinal quadrants. These findings suggest that pigment dispersion syndrome may be associated with developmental anomalies that are not restricted to the anterior chamber but involve other portions of the bulb as well.