Eye manifestations in acrodermatitis enteropathica

Proximal lacrimal obstructions: a review

PURPOSE

The aims of the review are to summarize the aethiopathogenesis, management and outcomes of different treatments of proximal lacrimal obstructions.

METHODS

An electronic database (PubMed, MEDLINE and Google Scholar) search of all articles written in English and non-English language with abstract translated to English on proximal lacrimal obstructions was performed. The articles were reviewed along with their relevant cross references. Data reviewed included demographics, presentations, investigations, management, complications and outcomes.

RESULTS

Punctoplasty is as effective as punctal dilatation with monocanalicular or bicanalicular stent in case of punctal stenosis. Dacryocystorhinostomy with retrograde intubation is more effective in case of proximal canalicular obstructions than in case of mid-canalicular obstructions. Trephination and intubation is effective in both mid and distal canalicular obstructions in patients with no associated nasolacrimal duct obstruction. Canaliculodacryocystorhinostomy has a specific indication in case of proximal common canalicular obstruction. Bypass surgery is the preferred treatment if there is no residual patency, however surgical success may not match patient satisfaction.

CONCLUSION

Optimal choice of surgical method depends on identification of the site of obstruction. Mini-invasive techniques should be avoided in cases that would only benefit from standard surgical treatment.

Punctal stenosis: definition, diagnosis, and treatment

Acquired punctal stenosis is a condition in which the external opening of the lacrimal canaliculus is narrowed or occluded. This condition is a rare cause of symptomatic epiphora, but its incidence may be higher in patients with chronic blepharitis, in those treated with various topical medications, including antihypertensive agents, and especially in patients treated with taxanes for cancer. The purpose of this review is to cover the medical literature, focusing in particular on definition, incidence, risk factors, etiology and treatment options.

Zinc and the Eye

Zinc, a trace element that influences cell metabolism through a variety of mechanisms, appears to play an integral role in maintaining normal ocular function. This element is present in high concentrations in ocular tissue, particularly in retina and choroid. Zinc deficiency has been shown in a number of species to result in a variety of gross, ultrastructural and electrophysiologic ocular manifestations. The physiological functions for zinc have been studied predominantly in retina and retinal pigment epithelium where zinc is believed to interact with taurine and vitamin A. modify photoreceptor plasma membranes, regulate the light-rhodopsin reaction, modulate synaptic transmission and serve as an antioxidant. Suboptimal zinc status in North America may influence the development and progression of several chronic eye diseases. Zinc supplementation trials and epidemiological studies have produced conflicting results concerning the role of zinc in age-related macular degeneration. Additional well-controlled supplementation trials are indicated to clarify the role of zinc in this disease. Future investigations must also expand our understanding of the mechanisms by which zinc regulates ocular morphology and function.

Ocular histopathology of acrodermatitis enteropathica

Acrodermatitis enteropathica is the clinical expression of congenital zinc deficiency and is now treated with supplemental zinc. This report details the ocular histopathology of a child who died before efficacious treatment was available. The findings include corneal epithelial thinning and loss of polarity, anterior corneal scarring and loss of Bowman's membrane, cataract formation, ciliary body atrophy, retinal degeneration, RPE depigmentation, and optic atrophy.

Peripheral corneal disorders

The peripheral cornea is anatomically and physiologically distinct from its central counterpart. The major differences relate to the gradual transition of corneal tissues to those of the conjunctiva, episclera, and sclera; furthermore, the vascular structures, lymphatics, and inflammatory cells from these neighboring structures are intimately associated with the limbus and periphery of the cornea. The peripheral cornea is thereby predisposed to three main classes of disorders which do not normally involve the central cornea. First, local conditions affecting the sclera and conjunctiva may secondarily spread to involve the limbus and peripheral cornea. These include several infectious diseases, as well as hypersensitivity conditions, mass lesions, and degenerations. Second, due to the associated blood vessels and lymphatics, the peripheral cornea may be involved in a variety of systemic diseases, including vasculitides, autoimmune disorders, and abnormal metabolic conditions. Finally, there are several conditions, such as the noninflammatory peripheral degenerations, which primarily affect the peripheral cornea without associated ocular or systemic changes. In this review, we present a classification and discussion of the various disorders which may involve the peripheral cornea.

Zinc metabolism in malabsorption syndromes

Zinc deficiency may complicate many gastrointestinal malabsorptive states. Zinc deficiency may manifest itself in a myriad of ways, ranging from skin lesions to immune dysfunction. This paper reports many of the ways in which zinc deficiency may appear in malabsorption syndromes and possible mechanisms for the development of this zinc deficiency.

Acrodermatitis enteropathica

A brief review of the clinical and biochemical features of Acrodermatitis enteropathica is given. This condition in now known to be caused by a systemic zinc deficiency secondary to a defect in the intestinal absorption of zinc and it illustrates the metabolic importance of this element in man.

Zinc in the eye

Zinc has long been recognized as an essential constituent of various tissues. Many clinical conditions and dietary factors reduce the absorption or the biological availability of zinc, and lead to zinc deficiency which produces structural and functional alterations in many organ systems. The highest concentration of this trace element in the human body is measured in the eye, particularly in the pigment-containing components. The deficiency of zinc has a dramatic effect on ocular development especially when it occurs during early prenatal period. Zinc is required for the structure and activity of many ocular metalloenzymes. Although the exact mechanism of its molecular and cellular functions are largely unknown the essentiality of this element in the component of the eye, including the retina, choroid, cornea and lens, is well established; it is also well known that zinc deficiency causes functional impairments in various parts of the eye. Zinc related toxicities have been shown in human and animal eyes.