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Background: So far, intravenously injected echographic contrast agents have not been able to overcome the lung circle, and their use was confined to the study of right-sided heart abnormalities. A new agent that is able to pass the pulmonary barrier has been manufactured, and it is currently under investigation in ophthalmology. Methods: A saccharide-based contrast agent (SHU 454) that is not able to overcome the lung filter has been compared in vitro with a new saccharide-based contrast agent (SHU 508 A) that is able to overcome the pulmonary barrier. They have been diluted in saline solution, and the reflectivity of the solution and the eventual sound attenuation have been studied with standardized A scan and a tissue model. Results: The solution with SHU 508 showed a higher reflectivity that lasted longer, without significant sound attenuation. Conclusions: The long-lasting period of the increased reflectivity will allow to better evaluate the normal and pathological vascular network in the eye and orbit, such as the evaluation of the effectiveness of conservative treatment in cases of malignant melanoma with a spread of the indications of standardized echography to other fields of ophthalmology.

To determine the accuracy of non-contact tonometry in patients with corneas thinned by photorefractive keratectomy, the authors measured the intraocular pressure with a non-contact tonometer and the corneal thickness with an ultrasonic pachymeter in 47 patients before and 9 months after photorefractive keratectomy. The patients were divided into three groups according to the degree of treatment: group I between 1 and 5 diopters (14 eyes), group II between 6 and 10 diopters (18 eyes), group III between 11 and 15 diopters (15 eyes). In the first group of patients mean intraocular pressure was 16.1 (+/-3.85) mm Hg before surgery, and 13.2 (+/-3.14) mm Hg after surgery with a significant difference (p = 0.0027). In the second group of patients mean intraocular pressure was 16.0 (+/-4.13) mm Hg before surgery and 13.0 (+/-3.0) mm Hg after surgery with a significant difference (p = 0.0045). In the third group of patients mean intraocular pressure was 17.7 (+/-3.8) mm Hg before surgery and 12.4 (+/-2.6) mm Hg after surgery, with a significant difference (p = 0.0005). In conclusion, according to our results, non-contact tonometry needs a correcting factor for measuring the intraocular pressure in patients that underwent photorefractive keratectomy, related to the degree of refractive treatment.

Eight patients, two male and six female, aged between 24 and 48 years, with Graves’ disease and severe ophthalmopathy were included in the study. A standardized A-scan echography was performed to evaluate the reflectivity of the extraocular muscles (EOMs); a planar scintigraphy (PS) and/or a single photon emission computed tomography (SPECT) were also performed at various times after endovenous injection of 111 MBq In-111 OCT, a somatostatin analogue.

At an early clinical stage, patients with cystoid macular oedema show no significant changes in their vision. This phase is described as angiographic cystoid macular oedema. Echographic macular studies have in the past years shown that the macular thickness is increased in the early stages of cystoid macular oedema. In these patients there was no evidence of cystoid macular oedema with the visual acuity test, B-scan echography and fluorescein angiography. In this paper an echographic macular study by standardized A-scan echography was performed in 537 patients before extracapsular cataract extraction and intraocular lens implantation in posterior chamber (ciliary sulcus). The results showed that this method is very sensitive in detecting patients with high risk of cystoid macular oedema.

Several authors have pointed out a correlation between perceptionand imagination. In particular some authors suggested that during imaginationnot only the brain, but also other structures are involved. It is possiblethat the eye too is involved in this process. For this reason we decided tostudy the role of the lens during the mental process of imagination: weexamined with standardized echography the lenses of 10 emmetropic subjects.The lenses were measured by ultrasound to verify changes in thicknesswhen some tests were submitted to the patients.

The presence of a choroidal detachment combined with a retinaldetachment sometimes can be misdiagnosed. The presence of cells in theanterior chamber, opacities of the lens, or vitreal haze may add trouble inthe evaluation of the fundus, which is already difficult to examine due to thepresence of the double detachment.

The clinical evaluation of an ocular disease in a patient with uveitis is often difficult due to opacities of the dioptric media. Hence standardized echography can be very important in the study of uveitis. The most common macular lesion associated with uveitis being the macular edema. Our results are presented from 42 eyes with uveitis. Our study points out a relation between visual acuity and retino-choroidal thickness in the macular area. In particular, our results show that a thickening of the macula may appear before a decrease in visual acuity.

The intravenous injection of an ultrasound contrast agent can enhance signals from blood flow. Broad toxicological and pharmaceutical studies in animals confirmed the safety and efficacy of an ultrasound contrast agent made of microparticles of galactose with stabilised microbubbles in watery suspension (SH U 508 A). In this paper 10 patients with different malignant orbital and ocular tumours have been evaluated with an echo colour Doppler machine before and after the injection of SH U 508 A. An enhancement of the Doppler signals in the lesions in different degrees has been detected. This echographic contrast agent seems to be very important not only in the evaluation of vascular lesions, but also in evaluating the effectiveness of radiotherapy in malignant tumours and could spread the echographic indications in several other ophthalmic fields.

Avellino corneal dystrophy has rarely been reported in literature. It consists of a combination of granular and lattice dystrophy. Patients may complain of glare and decreased night vision with or without decreased visual acuity, depending on the degree of corneal involvement. Current treatment for this dystrophy includes bandage contact lenses for the erosions or corneal transplant in the case of decreased visual acuity. We describe the first patient with Avellino corneal dystrophy to have been treated with phototherapeutic keratectomy.

The authors describe the role of a complete echographic examination with standardized echography before performing corneal graft surgery. During the examination it is important to establish vitreo-retinal conditions. When it is impossible to examine the anterior segment with a slit lamp, it is crucial to perform a careful examination of the anterior segment with echography, utilizing the immersion scleral shells according to K. Ossoinig.

X-ray irradiation and a galactose diet are two of the main approaches to experimental cataractogenesis that provide a useful model for examining the changes in the lens compared to human cataract. We measured the lens thickness in six sibling New Zealand rabbits with an RF signal, before and after irradiation and a galactose diet. In this paper we discuss our results and the importance of ultrasonic evaluation with an RF signal, to discover the early stages of cataract, before the appearance of lens opacities.

The potential of making differential diagnosis in optic nerve disease with standardized A-Scan echography has been well established. With this technique it is possible to differentiate 'solid' and 'fluid' thickening. A few years ago a new standardized A-scan equipment was built: The Mini A. With this equipment, it is possible to distinguish spikes coming from the pia, the arachnoid, and the dura around the optic nerve, and to measure the thickness of these structures with a precision of 0.03 mm. We found dura distance 4.0-5.3 mm, arachnoid 3.2-4.0 mm, an pial diameter 2.8-3.4 mm. In this paper the authors discuss their preliminary findings in a normal population.

Objectif Evaluer les changements precoces de la meilleure acuite visuelle corrigee (BCVA), de la sensibilite retinienne centrale, de l’epaisseur choroidienne et retinienne dans l’œdeme maculaire apres injection intravitreenne de Bevacizumab. Materiels et Methodes Etude prospective non-randomisee. Trente-sept yeux consecutifs avec œdeme maculaire (23 cas de neo-vascularisation choroidienne par DMLA exsudative, 8 cas de proliferation angiomateuse retinienne, RAP, et 6 cas de occlusion de branche veineuse) ont ete inclus dans l’etude. Dans tous les cas nous avons evaluees BCVA, epaisseur retino-choroidienne centrale a l’echographie A-scan standardisee, epaisseur retinienne centrale et sensibilite retinienne a l’evaluation avec OCT/micro-perimetre (OCT/SLO, OTI) avant les 7, 15, 30, 37, 45, 60 jours (D) apres la premiere injection. Tous les malades ont recu deux injections intravitreennes a un mois d’intervalle. Resultats Une amelioration significative de l’acuite visuelle etait presente entre D0 et D30 et entre D30 et D60. L’amelioration majeure de sensibilite retinienne etait presente au cours du premier mois apres l’injection (2.5 ± 3.7 dB, p = 0.003). Une amelioration de l’epaisseur retinienne etait presente dans les premieres 15 jours apres l’injection. Des changements significatifs de l’epaisseur choroidienne centrale n’ont pas ete detectes. Discussion Une amelioration significative de l’acuite visuelle, de la sensibilite et de l’epaisseur retinienne etait presente apres un mois et deux mois de suivi. Conclusion Le traitement de l’œdeme maculaire par injection intravitreenne de Bevacizumab determine des ameliorations precoces anatomo-fonctionnelles independamment de l’etiologie de l’œdeme.

But Evaluer l’epaisseur et le volume retinien avec la Tomographie par Coherence Optique (OCT) de domaine du temps (Stratus OCT) et avec OCT de domaine spectral (SLO/OCT) dans une serie d’yeux sains, avec myopie elevee et avec œdeme maculaire et/ou traction epiretinienne. Materiels et Methodes Cinquante-deux yeux sains, 30 yeux qui presentaient des alterations retiniennes (18 avec œdeme maculaire cystoide, 8 avec membrane epiretinienne, 4 avec les deux), et 10 yeux qui presentaient une myopie forte (> 6 dioptries) ont ete evalues avec Stratus OCT et SLO/OCT spectral. Resultats Une forte correlation etait presente entre les deux instruments dans la mesure du volume retinien. Le rapport entre l’epaisseur retinienne mesuree avec SLO/OCT spectral et OCT Stratus etait 1.1 avant l’exclusion des artefacts, 1.2 apres exclusion. La correlation entre les deux groups des donnes avant exclusion des artefacts (r = 0.59) etait considerablement inferieure qu’apres l’exclusion des artefacts (r = 0.84). Avec Stratus OCT des artefacts etaient presents dans 35 % des acquisitions, pendant qu’avec SLO/OCT spectral ils etaient presents dans 26 % des acquisitions. Tous les yeux avec haute myopie presentaient des artefacts a l’examen avec les deux instruments. Neanmoins, ils impliquaient la fovea centrale dans 8 cas evalues avec Stratus OCT, pendant qu’ils etaient toujours hors du centre a l’examen avec SLO/OCT spectral. Discussion Le SLO/OCT spectral fournit une plus haute resolution et vitesse que le Stratus OCT, avec une reduction considerable des artefacts. Conclusion Le volume retinien devrait etre considere comme un parametre important pour comparer les examens executes avec les deux instruments. Au moment de comparer l’epaisseur retinienne obtenue avec les deux instruments une valeur de correction devrait etre consideree.

A case of choroidal osteoma presenting in a 22-year-old girl is reported. The tumour, unilateral and in a juxtapapillary site, appeared markedly elevated on the retinal plane, not flat or slightly elevated as in previous reports. Visual acuity was not affected, and there was a complete absence of subjective symptoms. Echography, fluorangiography, computerised tomography, and visual field tests were performed. Echography is the best method for identifying and differentiating this lesion from a malignant tumour.

The authors present a retrospective echographic study on 140 patients with lacrimal fossa lesions, performed at the Institute of Ophthalmology—2nd Medical School—University of Naples.

A study of pseudophakodonesis of the IOL in anterior and posterior chamber was performed using the Radio frequency (RF) echographic signals. The results were similar but more accurate than those previously obtained using M mode echography: iridodonesis and firm IOL in the case of AC IOL implantation; no inertial movements of the iris and the IOL in the case of PC IOL implantation.

We measured the lens thickness in a group of patients with normal lenses compared to a group of patients with different age and with various types of lens opacities.

Introduction Le decollement peripapillaire de l’epithelium pigmentaire (RPE) et de la retine est une lesion reconnue recemment dans la myopie pathologique grâce a la tomographie en coherence optique (OCT). L’OCT a balayage laser (OCT/SLO) a ete introduit recemment et fournit des coupes non seulement longitudinales mais aussi coronales de la retine. Materiels et Methodes Quatre patients avec myopie forte qui presentaient une lesion lobulee jaune-orange peripapillaire bilaterale ont ete evalues avec angiographie a la fluoresceine (FA), angiographie au vert d’indocyanine (ICGA), OCT a balayage laser (OCT/SLO) et perimetre Humphrey. Resultats Dans tous les yeux l’angiographie a la fluoresceine montrait une hypofluorescence precoce et une hyperfluorescence tardive de la lesion, qui a l’angiographie au vert d’indocyanine resultait hypofluorescente. L’OCT a balayage laser a montre la presence d’un decollement peripapillaire de l’epithelium pigmentaire. L’ampleur laterale de cette lesion etait clairement detectable et la mesure de son epaisseur a ete obtenue. Nous avons trouve une fissure au bord du decollement du RPE dans deux yeux, des tractions vasculaires et des tractions vitreo-retiniennes dans deux yeux, un trou maculaire avec decollement du neuro-epithelium dans un œil. Dans les six yeux qui presentaient une bonne fixation centrale des alterations glaucomateuse du champ visuel etaient evidents. Discussion L’origine de l’hypo reflectivite sous le RPE pourrait etre l’excavation profonde du conus myopique avec, en consequence, l’impossibilite du complexe retine-RPE de suivre la choroide. De cette facon, un espace se formerait entre retine- RPE et choroide. Conclusion Dans tous les cas l’OCT a balayage laser a permis d’evaluer l’epaisseur et l’ampleur laterale du decollement peripapillaire de l’epithelium pigmentaire. Par consequent, son usage pourrait etre important pour evaluer les dimensions de ces lesions a la premiere visite et ainsi detecter des changements minimes de largeur et d’epaisseur pendant le suivi, realisant une alternative non invasive a l’angiographie a la fluoresceine.

But Evaluer l’epaisseur choroidienne au cours de l’œdeme maculaire avant et apres injection intravitreenne de triamcinolone acetonide. Materiels et Methodes Nous avons analyse prospectivement 100 yeux (70 patients) qui presentaient un œdeme retinien et qui ont ete traites par injection intravitreenne de triamcinolone acetonide. La cause de l’œdeme etait le diabete dans 52 % des cas, une occlusion de branche veineuse dans 20 % des cas, une neo vascularisation chorioretinienne maculaire liee a l’âge dans 18 % des cas, une proliferation angiomateuse retinienne dans 10 % des cas. L’epaisseur retinienne a ete mesuree par tomographie en coherence optique tandis que l’epaisseur chorioretinienne a ete mesuree en echographie A-scan standardisee. La difference entre l’epaisseur chorioretinienne et l’epaisseur retinienne a ete consideree comme indicative de l’epaisseur de la seule choroide. Apres l’injection, tous les patients ont ete traites par photocoagulation au laser a argon ou par therapie photodynamique. Les controles ont ete effectues avant l’injection et a 1 semaine, 1-3-6-12 mois apres l’injection. Resultats Avant l’injection, dans tous les cas, l’epaisseur choroidienne etait augmentee. Une semaine apres l’injection de triamcinolone, l’epaisseur s’est normalisee dans 77 % des cas. Dans 90 cas, elle est restee stable pendant les 12 mois suivants l’injection. Dans 10 cas, nous avons du repeter l’injection apres une periode moyenne de 10 (6-12) mois pour reprise de l’œdeme et dans tous ces cas l’epaisseur choroidienne etait de nouveau augmentee. Discussion Le role de la choroide en cours d’œdeme maculaire n’est pas encore clair. Les donnees echographiques montrent qu’un epaississement de la choroide semble etre present. Conclusion Les changements d’epaisseur enregistres avant et apres injection sembleraient indiquer une implication choroidienne. Le traitement de l’œdeme maculaire par injection intravitreenne de triamcinolone acetonide semblerait agir autant au niveau retinien que choroidien.

Introduction La tomographie en coherence optique a balayage laser (OCT/SLO) est une technique diagnostique de recente introduction qui fournit des coupes non seulement longitudinales mais aussi coronales de la retine. Pendant l’examen les coupes coronales peuvent etre superposees sur les cliches en vert confocales du fond d’œil. Le but de notre etude a ete d’evaluer avec l’OCT/SLO les modifications retiniennes retrouvees dans la myopie forte. Objectifs et Methodes Nous avons examine 200 yeux avec myopie forte (superieure a 6 dioptries) avec OCT a balayage laser (OCT/SLO). Resultats Dans tous les cas nous avons obtenu une visualisation de bonne qualite de l’epaisseur et de l’extension laterale des lesions. Un decollement du neuroepithelium etait present dans 21 % des cas (12 % sans trou maculaire, 9 % en presence d’un trou maculaire), un trou maculaire sans decollement etait visible dans 3 % des yeux, des tractions vasculaires et des mycro-kystes paravasculaires etaient presents dans 20 % des yeux, un decollement peripapillaire de l’epithelium pigmentaire etait decelable dans 5 % des yeux. Discussion L’OCT a balayage laser a permis d’evaluer et de mesurer l’extension laterale et la profondeur des alterations retiniennes chez le myope fort. La possibilite de superposer les coupes coronales sur les cliches en vert confocales du fond d’œil facilite la definition des relations entre les alterations et les structures du pole posterieur. Conclusion L’OCT a balayage laser pourrait representer une methode diagnostique non invasive pour le suivi des alterations retiniennes chez le myope fort.

Introduction L’iridoschisis est une pathologie rare au cours de laquelle une partie de l’iris se separe en deux feuillets dont la portion anterieure se fend en fibrille. Elle est frequemment associee a un glaucome par fermeture de l’angle et a une cataracte. Observation Un homme, âge de 70 ans, consulta pour une baisse de vision a l’œil gauche. L’acuite visuelle etait de 8/10 e a droite et de 3/10 e a gauche, la pression intraoculaire etait de 12 mm Hg a droite et de 46 mm Hg a gauche. L’examen biomicroscopique mit en evidence bilateralement une chambre anterieure peu profonde, une cornee transparente, une atrophie de l’iris et une fragmentation du feuillet stromal. La gonioscopie montrait une fermeture de l’angle par des synechies anterieures etendues inferieurement sur 180 a l’œil droit, et etendues inferieurement et superieurement a l’œil gauche. Un epaississement du cristallin et la presence de quelques masses floculees hyperechogenes fluctuantes dans le vitre etaient visibles a l’echographie A scan standardisee et a l’echographie B scan 10 MHz. A l’echographie de haute frequence (20 MHz), une augmentation modeste de l’epaisseur des proces ciliaires etait observee. Conclusion La relation entre iridoschisis et glaucome n’est pas connue. L’augmentation de la pression intraoculaire pourrait etre due a la presence conjointe d’une fragmentation primitive de l’iris en fibrilles occluant le trabeculum et d’un bloc pupillaire, favorise par l’epaississement et l’anteriorisation du cristallin et des corps ciliaires.

The authors report 3 cases of familial microphthalmos associated in 2 cases with ichthyosis and in another with deafness. The presence in 2 cases of epibulbar cysts echographically documented leads us

The authors report an unusual case of exophthalmos, deficiency of the VIth nerve and of bilateral optic atrophy in a patient affected by intracranial meningiomatosis. The problem relating to the mechanism of development of exophthalmos is dealt with. Those cases in which direct invasion of the orbital cavity can be excluded with certainty indicate pathological compression on the cavernous sinus as the mechanism responsible for the symptomatology.

The authors, after reviewing the literature, particularly the classification of optic nerve-head abnormalities, describe several clinical cases dealing especially with the notable diagnostic possibilities of ultrasound examination.

Monoclonal antibodies reacting with cell surface antigens of helper (T4), suppressor (T8) T cells and common T-cell antigen (T3) were used by an immunofluorescence technique to enumerate peripheral T-lymphocytes in 37 patients suffering from euthyroid Graves' ophthalmopathy. According to the time when the disease appeared, the patients were divided into two groups: the first group in whom the disease was present for less than three years, and the second group, in whom the disease had lasted for more than five years.The most important finding was a decrease of OKT8+ cell-percentage in patients in whom the disease had lasted for less than three years. The results confirm the hypothesis made by Volpe that the ophthalmopathy can be considered as a new autoimmune organ-specific disease and that it must be considered to be separated from the autoimmune thyroid disease.

A and B-Scan echography, CT scanning and pathological studies have clearly shown that the extraocular muscles are the primary focus in orbital Graves’ disease. The presence of optic neuropathy is probably secondary to apical orbital compression by congested muscles. At present the Standardized A-Scan echography is a reliable method for precise biometrical estimation of the thickness of the optic nerve. The purpose of this work is to evaluate the diameter of the optic nerve in patients with Graves’ disease in relation to the involvement of this structure in this disease.The results show that the optic nerve can be affected in Graves’ disease already in the very first stage of the disease. There is moreover a discrepancy between the thickening of the optic nerve and the progression of Graves’ disease.A hypothesis is given to explain these data.

The authors report a case of ethmoidal schwannoma with orbital extension in a 31-year-old female patient. the neoformation affected the left orbit by erosion or osteolytic changes of the medial walls and extended onto the frontal sinus, the floor of which appeared eroded at the nasal fossa and the homolateral maxillary sinus. Ultrasound examination and computerized tomography were carried out: the preliminary diagnosis was confirmed by histology of a tissue biopsy.

Seventy-seven patients affected with recurrent episodes of common and classic migraine were examined by means of thermography and 37 out of the group also by means of ophthalmodynamometry with or without the ophthalmic test.The aim was to reveal circulatory modifications in the sphere of the internal and external carotid arteries, during intercritical periods.The negative ophthalmodynamometrical results regarding a stenosis producing pathology at the origin of the internal carotid and the positive thermographic results, led the authors to postulate that the circulatory modification should be sought not in variations of the capacity of the large vessels, but in changes in the microcirculation.

A case of morning glory syndrome with striking persistence of primary vitreous is presented. The hypothesis that the syndrome is an expression of abnormal closure of the embryonic fissure is substantiated by the coexistence of lens colobomas. Furthermore, the marked primary vitreous hyperplasia shows the way in which persistence of primary vitreous influences the clinical expression with respect to optic pit and colobomas of the optic nerve.

Standardized A scan echography is the best technique for the biometric parameters of the eye. This has been very useful in studying the sizes of the anterior and posterior segments of the eye in hereditary microphthalmos. Echography and a genetic study led to a new classification of hereditary microphthalmos.

Thin ocular layers can be characterized by analyzing RF echo signals in the time domain and/or in the frequency domain. In the first case the time interval between pulses reflected from anterior and posterior surfaces gives immediately the thickness measurement if the sound velocity is known. In the second case, by considering that the power spectrum can be interpreted as a plot of tissue reflectivity vs frequency, the above mentioned time interval is obtained as the inverse of the difference between two successive frequencies of the power spectrum.

Lymphocyte surface markers (using E active -, E total -, EA- and EAC-rosettes and membrane immunoglobulin assay) were examined in 34 clinically and biochemically euthyroid patients with Graves' ophthalmopathy, in 19 hyperthyroid patients with Graves' disease and exophthalmos (12 untreated and 7 treated), in 7 patients with inflammatory or malignant exophthalmos, and 74 control subjects. Results suggest that the percentage of T and B lymphocytes and EAC-rosette-forming cells in patients with Graves' disease was not significantly different from that observed in the controls. In contrast, EA-RFC seemed significantly involved ( P The ability of antithyroid agents to affect circulating cell populations (i.e. immunomodulator activity of methimazole) was also observed.

43 clinically euthyroid patients with unilateral exophthalmos were examined using clinical methods, echography, and computerized tomography. The functioning of the hypothalamic-hypophyseal-thyroid axis was investigated by measurements of TSH (before and after stimulation with TRH), thyroid hormones and antithyroglobulin antibodies. After a review of the literature, the results are discussed.

The standard X-ray preserves its value in verifying the presence of a foreign body (FB). The echography is valuable in verifying the site of a FB when it remains uncertain in respect to the sclera after X-ray localization. Computerized tomography scanning offers useful information about the physical nature of the FB.

A 42-year-old woman had morning glory syndrome of the fundus of the right eye. The finding was related to chronic simple glaucoma and without pulsation of the staphyloma. The clinical symptoms and echographic pattern during the endocular hypertensive phase with normal intraocular pressure was studied after appropriate medication. This associated disease is attributed to the presence of a congenital malformation of the anterior chamber angle.

Significance: A noninvasive method based on surface-enhanced Raman spectroscopy (SERS) of tears was proposed as a support for diagnosing neurodegenerative pathologies, including different forms of dementia and Alzheimer’s disease (AD). In this field, timely and reliable discrimination and diagnosis are critical aspects for choosing a valid medical therapy, and new methods are highly required. Aim: The aim is to evince spectral differences in SERS response of human tears from AD affected, mild cognitive impaired (MCI), and healthy control (Ctr) subjects. Approach: Human tears were characterized by SERS coupled with multivariate data analysis. Thirty-one informed subjects (Ctr, MCI, and AD) were considered. Results: Average SERS spectra from Ctr, MCI, and AD subjects evidenced differences related to lactoferrin and lysozyme protein components. Quantitative changes were also observed by determining the intensity ratio between selected bands. We also constructed a classification model that discriminated among AD, MCI, and Ctr subjects. The model was built using the scores obtained by performing principal component analysis on specific spectral regions (i-PCA). Conclusions: The results are very encouraging with interesting perspectives for medical applications as support of clinical diagnosis and discrimination of AD from other forms of dementia.

Antihistamines (histamine H1 receptor antagonists) are effective and convenient drugs for the treatment of allergic conjunctivitis. Because of the short duration of action generally observed for drugs administered topically to the eye, the oral route is often preferred. However, the presence of a selective barrier between blood and ocular tissues, the so-called blood-ocular barrier, does not allow a priori assessment of the most suitable dosage for ocular therapy. To investigate the tear concentrations of cetirizine, a second-generation antihistamine, over time following oral administration, and to study the relationship between plasma and tear fluid concentrations. Pharmacokinetic study of a single oral dose of cetirizine 10mg in 40 patients treated for allergic conjunctivitis. Patients received a single oral dose of cetirizine. Samples of blood and tear fluid were taken according to predefined sampling schedules and the concentrations of cetirizine were determined by a new high performance liquid chromatography method. Concentration-time profiles for cetirizine in serum and tear fluid were similar, although the mean maximum concentration in tear fluid was reached later than in serum (90 and 30 min, respectively). However, at 60 and 120 min the cetirizine concentration in tear fluid was 98 and 92% of the mean maximum concentration, respectively, showing a plateau region and indicating that the disposition rate for the tear fluid compartment was very similar to that for the blood compartment. Oral administration of cetirizine yields therapeutically effective concentrations of the drug at the anterior surface of the eye.