Ocular mucins: Purification, metabolism and functions

Mucins are present at the ocular surface in both secreted and membrane-bound forms. Mucins are produced in partby the conjunctial goblet cells, and are complemented by non-globet secretions. This review focuses on secreted ocular mucins. They are present in the tear film, probably both in gel and soluble form, and play a role in lubrication and ocular defense. It is apparent that mucins are highly adapted to their functions. State of the art techniques for mucin purification and analysis are presented. Density gradient centrifugation, gel filtration, ion-exchange chromatography and agarose gel electrophoresis are discussed, together with methods of oliogosaccharide analysis. Reagents for the detection of mucin are considered in conjunction with these methods, which we have employed in the analysis of human and canine ocular mucins. The general structure of mucins is reviewed. The biosyntheas and glycosylation of ocular mucins are not yet fully understood, and are discussed in relation to currently established concepts. The impaact of disease on the nature and secretion of mucins is considered, as well as the physiological and pathological significance of mucus degradation.     

Management of canalicular laceration

Although canalicular injuries are relatively common, controversy persists regarding indications for repair and the surgical methods that should be employed. In this review, these various treatment philosophies and techniques are analyzed in an historical and a contemporary context. The surgical anatomy, epidemiology and clinical presentation of canalicular injuries are discussed. Inconsistencies in current nomenclature regarding the surgical anatomy of canalicular lacerations are analyzed. Recent studies of lacrimal drainage in systems with monocanalicular obstruction are cited. Various surgical techniques in the repair of canalicular injuries are reviewed, including methods of identifying the medial lacerated lacrimal passages and the various lacrimal stents that have been used. The current popularity of silicone tubing as a lacrimal stent is reviewed. The various methods of stent placement and fixation are systematically categorized. Case series of canalicular repair reported in the literature are reviewed, and the results and complications are compared.     

Peripheral proliferative vitreoretinopathy in intermediary uveitis

Certain types of intermediary uveitis are accompanied by proliferative vitreoretinopathy and retinal detachment. As a rule both complications are confined to the fundus periphery; they often occur simultaneously but they are not always related to one another. Exudate plaques and/or neovascularizations at the base of the vitreous are the precursors of peripheral proliferative vitreoretinopathy. Clinical findings and their therapeutic consequences are discussed.     

The unwanted ocular effects from topical ophthalmic drugs. Their occurrence, avoidance and reversal

Unwanted effects may occur when drugs are applied topically on the eye or when they are administered by other routes. The unwanted effects may be ocular, systemic or both. This paper discusses unwanted ocular effects which may arise when certain optometric drugs are applied directly on the eye. Among the effects described are allergic reactions, infections, pigmentary changes, and the production of aqueous "floaters." Changes in intraocular pressure and appropriate first aid measures to counter an acute rise in IOP are also discussed. Not discussed are the adverse ocular effects which are associated with topical application of the potent anticholinesterases nor those which can arise when certain drugs e.g. corticosteroids are applied to the eye for therapeutic purposes.     

眼部嗜酸细胞腺瘤的临床表现及病理特点

目的 探讨眼部嗜酸细胞腺瘤的临床诊断,以提高诊断准确性.方法 回顾性分析经病理学及免疫组化证实的6例眼部嗜酸细胞腺瘤患者的临床及病理学资料.结果 (1)临床表现:除1例眼球轻度突出外,多数患者无明显症状,偶有异物感、流泪、眼红痛等不适.病变全部单发,其中泪阜3例,泪囊、泪腺及睑结膜各1例.2例经CT检查,1例显示右眼泪阜区域一高密度病灶;1例显示眶外上方泪腺区一卵圆形高密度影;后者行眼B超探查显示眶外上方一卵圆形较强回声团.(2)病理学特征:肿块多为圆形或卵圆形,表面光滑,直径1～4cm不等.肿物包膜完整,切面呈棕红色或灰红色,1例伴有小囊腔,内含褐色液体.肿块全埋制片,HE染色,光镜下显示组织学形态较一致,主要由体积较大的嗜酸细胞组成,排列成巢状或呈腺样结构.以腺样结构为主者瘤细胞嘲形或柱状,胞浆丰富,嗜酸颗粒异常清楚,核圆或椭圆,小而深染,核仁不明显,未见分裂象.(3)免疫表型:免疫组化(LSAB法)染色显示EMA在胞质和胞膜强表达,而S-100及vimentin均未见阳性表达.结论 眼部嗜酸细胞腺瘤临床症状不明显,病理学及免疫组化检查有助于诊断及鉴别诊断.     

Meridional profiles of variance—covariance of dioptric power, Part 2. Profiles representing variation in one or more of sphere, cylinder and axis

Meridional profiles of variation of dioptric power are constructed. Using the basic theory developed in an accompanying paper, samples are selected in a systematic way to illustrate variation only in sphere, only in cylinder and only in axis, and in all possible combinations of sphere, cylinder and axis. For each of the seven samples, scatter plots are constructed together with ellipsoids that represent the estimated distribution of powers in the population from which the sample was taken. The surfaces of the ellipsoids are surfaces of constant probability density within which 95% of the population is calculated to lie. The scatter plots and distribution ellipsoids are plotted in a three-dimensional space called h-space. Meridional profiles of variation are constructed for each of the samples. Properties of the profiles are discussed. Meridional profiles are also presented for eyes before and after radial keratotomy. Among other things, the profiles show meridians of greatest and least variation and are intuitively satisfying. They are potentially useful for the researcher and clinician including the surgeon. They may help to improve surgical and therapeutic techniques. Certain patterns may prove to be characteristic of physiological or pathological conditions, in which case meridional profiles may have use as a diagnostic tool.     

Eye size of pelagic crustaceans as a function of habitat depth and possession of photophores

Eye diameter, interommatidial angle, and rhabdom dimensions were measured for a variety of crustacean species differing in habitat depth and bioluminescence ability. Eyes are smaller and eye growth rates are lower at greater depths for species in five of the six families examined, and photophore-bearing species tend to have larger eyes than relatives which lack photophores. Rhabdoms are smaller and interommatidial angles are larger in small eyes, factors which, with reduced aperture size, are generally associated with decreased visual sensitivity and acuity. This suggests that the eyes of many deep-sea crustaceans are poorly suited to a dimly lit environment; however, the small eyes of deep-sea crustaceans may still perceive luminescent sources from appropriate distances because of the much higher contrast at depth between luminescent sources and background light. Smaller eyes also impose a lower energetic burden and are potentially less visible to predators than are large eyes.     

Peptidergic neurons of teleost retinas.

In retinas of teleost fish, neuropeptides typically have subtle, modulatory actions. The peptide effects typically have long latencies and durations, and, in some instances, they are known to be mediated by second messengers. Peptidergic neurons in teleost retinas have certain morphological features in common that are consistent with their function. Most peptidergic neurons are stratified amacrine cells with long, varicose processes; the processes of peptidergic centrifugal axons are also narrowly stratified and ramify extensively in the retina. The peptidergic amacrine cells are relatively infrequent, and, likewise, the centrifugal axons originate from a small number of perikarya in the brain. Cells that are so sparsely distributed and whose processes overlap so extensively are better-suited for modulation than for conveying detailed representations of visual space.     

A new set of variable-contrast visual acuity charts

Using a computer plotting technique, we designed four variable-contrast visual acuity charts. The contrast of the first 3 is 90, 15, and 2.5%, respectively. The fourth is 90%, but the luminance of the optotypes and background are the reverse of the first chart. The main features of these charts are as follows. Both contrast sensitivity and spatial frequency are in geometric gradation, which observes the laws of Weber and Fechner. The mean average luminance, (Lmax + Lmin)/2, is constant for all four charts, which follows the concept of contrast sensitivity function (CSF). Charts 1 and 4, which have the same contrasts but different glare backgrounds, measure the glare that is related to the transparency of the refractive media of the eye. Because the charts are rotatable, patient memorization and guessing are minimized. Results compared with those of the conventional visual acuity test and are understandable by patients and eye care practitioners. The charts, which are simple, easy, and require little time, are inexpensive and portable.     

The eye and headache

Ophthalmologists are often the first physicians to evaluate patients with headaches, eye pain, and headache-associated visual disturbances. Although ophthalmic causes are sometimes diagnosed, most eye pain and many types of visual disturbances are neurologic in origin. Afferent and efferent symptoms and signs are associated with headache disorders. This article reviews the primary headache disorders and focuses on their ophthalmic manifestations. The major divisions are migraine and the trigeminal autonomic cephalgias.     

Technics for exploring the optic nerve

This issue propose an inventory of the methods of investigation which help for the diagnosis of the optic neuropathies. These investigation methods are shortly presented, and the situation in which there are usefull are presented. Some of these investigation are expensive and are not available in any ophthalmological hospitals. Despite of the great number of investigations, the problem of the etiopathogenesis of the optic neuropathies is not completely elucidated.     

Bioelectric measurements in the frog lens

Three kinds of experiments are presented which suggest that fiber membranes deep in the lens are intact. In the first of these, Procion type dyes are electrophoretically infused into lenses of frogs through glass capillary microelectrodes. This dye stays within the confines of an individual fiber unless current levels are too large. In the second, double barrel microelectrodes are used to measure input resistances of individual fibers. The variability of repeat measurements from the same lens suggests different cells are being measured. Also, the charging times measured are compatible with the capacitance expected from a single lens fiber. These charging times are too brief to be compatible with the idea that the lens potential develops across a layer or two of superficial cells. In the third, potential differences profiles are measured as a glass microelectrode is driven into normal and hyperosmotic Ringer's treated lenses. In the hyperosmotic treated lenses, the electrode is found to pop in and out of individual fibers.     

An acute inflammatory reaction to silicone stents

Silicone stents are commonly used to intubate the nasolacrimal system, and are left in place for several months. They are generally well-tolerated, but are not without complications. We report an unusual inflammatory reaction associated with the presence of a silicone stent that occurred in an individual who previously rejected several silicone implants in her metatarsal joints. The possible etiology and significance of a silicone allergy are discussed.     

Contrast coding and magno/parvo segregation revealed in reaction time studies

Reaction times (RTs) are obtained for a wide range of contrasts of vertical sinusoidal gratings. The data are plotted as a function of the reciprocal of contrast. In some conditions, a single linear function accounts for the data. In others a clear bi-linear function is obtained. The low and high contrast regions of the function are interpreted as representing magno and parvo activity, respectively. RT-based supra-threshold sensitivity functions are obtained for different luminances, stimulus durations and eccentricities and these are compared with conventional threshold-based sensitivities to establish the extent to which RTs and contrast sensitivity are constrained by the same sensory processes.     

Albinism.

There are seven forms of oculo-cutaneous albinism, which are all autosomal recessive: three are tyrosinase-negative (complete oculo-cutaneous albinism, Amish albinism, Hermansky-Pudlak syndrome) and four are tyrosinase-positive (incomplete oculo-cutaneous albinism, Chediak-Higashi syndrome, Cross syndrome, Bergsma's albinism). There are three forms of sex-linked albinism: ocular albinism, which is intermediary sex-linked, Fran?ois-De Rouck syndrome and Ziprkowski syndrome, which show a generalized albinism and are recessive sex-linked. There are two principal forms of cutaneous albinism, one without deafness and the other with deafness (Waardenburg-Klein syndrome).     

Pentacam--the new way for anterior eye segment imaging and mapping

Accurate preoperative measurements are required for refractive and cataract surgery. Pentacam is a new imaging system for anterior eye segment study. The authors present technique and the range of measurements; topography of both anterior and posterior corneal surface from limbus to limbus, densitometry, anterior chamber angle, volume and depth, lens densitometry and 3D-virtual model of the anterior eye segment are taken. All those structures are shown thanks to rotating Scheimpflug camera, which generates three-dimension images. Any eye movements are detected by a second camera and corrected for, in the process. All results are written down on PC and are available for the prospective studies.     

Vitamin D-dependent calcium binding protein immunoreactivity in human retina

Using immunohistochemistry, vitamin D-dependent calcium binding protein (D-CaBP) has been detected in human retina. In the photoreceptor layer the cones are positive but the rods are negative. In the inner nuclear layer, horizontal cells and some bipolar cells are D-CaBP. In the ganglion cell layer both small and large somata are immunoreactive for D-CaBP. Beaded fibres from the outer plexiform, inner plexiform and fibre layers are also positive.     

Complications associated with contact lens solutions

The complications that have been seen when hydrophilic lenses are cared for by chemical decontamination are reviewed. The findings that help to differentiate lens-induced changes from chemical-care-produced changes are presented. Incompatibilities between care methods are illustrated. The complications are discussed in terms of changes produced in the cornea, conjunctiva, flora of the cul-de-sac, and lens.     

Retinal detachments and intraocular lenses.

1. Increasingly more patients with PPRD are seen. A retinal detachment can occur after any type of implant or cataract extraction. 2. The pseudophakic patient is better equipped than the aphakic patient to recognize symptoms of a retinal detachment, and most PPRDs are seen soon after they occur. 3. Visual access to the retina is sometimes decreased. The IOL requires more precautions. Hazy media and lens remnants are a major handicap, and the examination is more difficult and time-consuming. 4. Characteristic pseudophakogenic retinal changes or breaks are not obvious. Retinal tears are small and located near the ora serrata retinae. 5. When the breaks are found, the lengthy examination can be followed by a simple scleral buckle with minimal insult to the eye. When the breaks are not found, the treatment is extensive. 6. The anatomical and visual results are comparable to results of other rhegmatogeneous retinal detachments.