The Glenn A. Fry invited lecture. Accommodation to gratings and more naturalistic stimuli

An array of stimulus characteristics, such as spatial frequency content, contrast, color, and size, as well as higher-level control aspects, such as cognitive demand, instruction set, and volitional effort, may influence the steady-state accommodative response. Several experiments are reviewed which demonstrate clearly the remarkable robustness of accommodation to marked variations in these parameters. The retinal luminance gradient appears to be the primary determinant of overall response accuracy. These findings are of theoretical interest in understanding basic aspects of accommodative control, as well as being of practical importance. They suggest that the accommodative response remains relatively stable and accurate despite dynamic changes in retinal-image quality which occur under experimental and clinical, as well as more naturalistic, viewing conditions.     

Benign pigmented lesions of the eyelids

We describe benign pigmented tumors of the lids, including benign lesions of the epithelium such as papillomas, seborrheic keratosis, and inverted follicular keratosis; precancerous lesions of the epithelium such as xeroderma pigmentosum and actinic keratosis; melanocytic lesions such as Ota nevus, lentigo, and lentigo maligna; and nevi and other lesions simulating a melanoma such as pigmented hidrocystoma, angiomas, and epithelial cyst. For each of these lesions, we describe the clinical and histopathological aspect as well as the therapeutic guidelines.     

Documentation as a defense to legal claims

Proper documentation and record keeping serve to protect the professional, as well as the patient. Complete and accurate records are the foundation of an optometrist's practice, as well as the best source of defense in the event of litigation.     

Improvement of visual acuity in lens opacities using an optic aperture (author's transl)]

A diaphragm, placed in front of the eye acts as an artificial pupil as well as a field stop. The improvement of visual performance in the presence of opacities is due to its action as a field stop.     

The role of medical therapy in the rank order of glaucoma treatment.

There is no consensus as to how treatment of open-angle glaucoma should be initiated. Medical therapy, laser trabeculoplasty, and filtration surgery each have their advocates as the best modality for initial treatment. The advantages and disadvantages of these three options are discussed here. It is pointed out that there may not be a single answer as to how to begin treatment. Patient factors such as age, general health, and stage of glaucoma as well as various socioeconomic and technologic factors may lead to different recommendations for different patients. At present, most patients with open-angle glaucoma are started on medical therapy. beta-Blockers are used most commonly as the initial drug of choice, but latanoprost and brimonidine are now being recommended by many as alternate first-line therapy.     

Role of structural cells of the cornea and conjunctiva in the pathogenesis of vernal keratoconjunctivitis

Vernal keratoconjunctivitis (VKC) is a severe type of allergic conjunctival disease characterized by the presence both of various corneal epithelial and stromal lesions as well as of conjunctival proliferative changes such as giant papillae of the upper tarsal conjunctiva and limbal lesions. These clinical findings as well as various pathophysiological characteristics of VKC are distinct from those of other types of ocular allergy and allergic diseases of other organs. The outer eye possesses specific allergological characteristics, one of which is communication between the cornea and conjunctiva through a thin layer of tear fluid. Fibroblasts of the cornea and the conjunctiva are activated by proinflammatory and T helper 2 (Th2) cell-derived cytokines. Corneal fibroblasts enhance ocular allergic reactions as a result of their activation-induced expression both of chemokines such as eotaxin and TARC as well as of adhesion molecules such as ICAM-1 and VCAM-1, all of which together promote the activation and infiltration of eosinophils and Th2 lymphocytes. In contrast, corneal epithelial cells suppress such reactions by physically separating corneal fibroblasts from bioactive substances in tear fluid. Exaggerated proliferation of and deposition of extracellular matrix by conjunctival fibroblasts likely exacerbate conjunctival inflammation. Restoration of an intact corneal epithelium and inhibition of the activities of corneal and conjunctival fibroblasts may provide a basis for the development of new treatments for severe ocular allergic diseases such as VKC.     

The effect of ketorolac tromethamine in reducing postoperative inflammation: double-mask parallel comparison with dexamethasone

Anterior chamber fluorophotometry was done after the oral administration of fluorescein sodium in patients undergoing extracapsular cataract extraction and posterior chamber intraocular lens insertion before and after surgery. The administration of ketorolac solution 0.5% eye drops before and after surgery decreased the breakdown of the blood-aqueous barrier as much as did dexamethasone sodium phosphate solution 0.1% (dexamethasone solution) eye drops at each postoperative time period as measured by fluorophotometry. Slit-lamp observations of postoperative anterior ocular inflammation were not different between treatment groups. Both ketorolac and dexamethasone solutions were well tolerated by patients. No additional corticosteroids were given to any patients during the study. Therefore, ketorolac solution was as effective as dexamethasone solution in suppressing postoperative inflammation after cataract surgery as measured by fluorophotometry and as observed by slit-lamp examinations. This study confirms prior studies that suggest ketorolac ophthalmic solution 0.5% may be effective and safe as a nonsteroidal antiinflammatory agent for topical use after cataract surgery and intraocular lens implantation and as a substitute for topically applied corticosteroids.     

The zebrafish as a model organism for eye development

In recent years, the zebrafish has become a favourite model organism for biologists studying developmental processes in vertebrates. Its rapid embryonic development, the transparency of its embryos, the large number of offspring together with several other advantages make it ideal for discovering and understanding the genes that regulate embryonic development as well as the physiology of the adult organism. Zebrafish are very visually orientated, and their retina and lens show much the same morphology as other vertebrates including humans. For this reason, they are well suited for examining ocular development, function and disease. This review describes the advantages of the zebrafish as a model organism as well as giving an overview of eye development in this species. It has a particular focus on morphological as well as molecular aspects of the development of the lens.     

Conjoint therapy: a cooperative psychotherapeutic-optometric approach to therapy

Optometrists often see patients who have psychological problems as well as visual problems. These patients are often referred to other disciplines for appropriate care. Although it is recognized that visual problems and emotional problems affect each other, after the appropriate referral very little interdisciplinary interaction occurs. The authors believe that this interaction--Conjoint Therapy--is frequently crucial for the successful remediation of the patient's emotional problem as well as his visual problem. They present in this report, just such a case with an anecdotal abstract from the psychological as well as the visual therapy reports.     

Congenital innervation dysgenesis syndrome (CID)/congenital cranial dysinnervation disorders (CCDDs)

Congenital loss of innervation to the extra-ocular muscles (EOMs) can have a profound effect on the target muscle. This has been well recognised in Duane''s retraction syndrome. However, it has been less emphasised in other congenital oculo-motor disorders. Such congenital ocular motor defects have been expanded to include DRS, congenital fibrosis of EOMs, monocular elevation defect, Möbius syndrome, as well as several other non-ocular muscles supplied by cranial nerves such as facial muscles. Such loss of innervation to motor muscles can be unified as a defined clinical entity, which can be labelled as congenital innervation dysgenesis syndrome or CID for short. CID may also affect other muscles supplied by nerves other than the cranial nerves and may be sensory as well as motor.     

Vision testing in the pediatric population

The goal of office testing of the child remains the same as it is for the adult--to gather as much information as efficiently as possible. Clinical testing of the child requires familiarity with the limitations available tests. Perhaps most important is the ability choose the proper test to use at every development stage. Cooperation may be surprisingly good in to hands of experienced examiners, though very young children can be unpredictable. The general ophthalmologist should not fear having young patients but rather take joy in the interaction with them. Armed with as many tools as possible, the challenge of testing children can be converted to the reward of helping families.     

The lipid layer of tears: dependent on meibomian gland function

There is growing laboratory and clinical evidence implicating the meibomian glands of the eyelid as playing a critical role in the pathogenesis of various ocular surface disorders such as chronic blepharitis and dry eye. Meibomian glands produce a lipid material whose synthesis is dependent on factors such as stem cells, neurological stimulants and hormones. This lipid material is fluid, spreads easily, is a surfactant as well as an aqueous barrier, and must remain functional after a blink. Before delivery it can be modified by factors such as hormone abnormalities and even after delivery it may be modified by lipases produced by ocular bacteria.     

Iris claw lens

The iris claw lens does not have some of the disadvantages of lenses fixed in the anterior chamber angle. It is clipped to the iris from the front and does not touch the structures of the angle. It is useful as a stand-by lens and for secondary implantations, as well as for certain other indications, such as a traumatized eye with anterior synechiae. It is conceivable that in the future this lens type may gain in importance as a carrier of a concave optic for use in myopic eyes.     

Resistance of transparent plastics to surface abrasion

This paper investigates the abrasion resistance of vurious lenses using a new testing apparatus. Many coated plastic lenses performed nearly as well as glass, however some were little better than uncoated CR39. The best coated-polvcarbonate lens performed as well as the best coated-CR39 lens     

Early primary congenital glaucoma

Early primary congenital glaucoma belongs to the category of primary congenital glaucomas and is regarded as one of the most frequent form of congenital glaucoma, in which case the intraocular hypertension usually appears in as early as the first year of living before the age of three or four, caused by mesodermic anomalies during the development of anterior chamber angle, leading to the stretching of the scleral wall and to the increase of the eye, known as buphthalmos and which associates with no other ocular or systemic anomaly. It is more frequently met as a bilateral one. The diagnostic methods include: history, the measurement of corneal diameter, the slitlamp examination, tonometry, gonioscopy, ophthalmoscopy, ultrasonography. The basic treatment is a surgical operation and must be provided as soon as possible.     

青光眼睫状体炎综合征误诊误治临床分析

目的探讨青光眼睫状体炎综合征误诊误治的原因。方法收集1999年8月~2004年7月我院门诊确诊的25例(25只眼)青光眼睫状体炎综合征患者,总结患者在外院误诊误治情况并进行回顾性临床分析。结果25例(25只眼)青光眼睫状体炎综合征在外院被误诊原发性青光眼14例(14只眼),占56%;虹膜睫状体炎7例(7只眼),占28%;疱疹性葡萄膜炎2例(2只眼),占8%;中间葡萄膜炎1例(1只眼),占4%;Fuchs虹膜异色性葡萄膜炎1例(1只眼),占4%。在治疗方面均与青光眼睫状体炎综合征治疗原则不相符合,其中9例(36%)在外院施行了抗青光眼滤过手术。结论青光眼睫状体炎综合征在临床上误诊误治普遍存在,首先它容易被误诊为原发性青光眼和虹膜睫状体炎,其次为疱疹性葡萄膜炎、中间葡萄膜炎和Fuchs虹膜异色性葡萄膜炎。应重视青光眼睫状体炎综合征的诊断与治疗,注意与上述眼病鉴别,减少对青光眼睫状体炎综合征的误诊误治。     

Connatal dacryostenoses. Clinical picture and treatment

Connatal dacryostenosis involves obstructions of the lacrimal passages in all parts of the system as well as supernumerary structures like the connatal fistula of the lacrimal sac. Usually intervention in infants with aplasia of the puncta is not necessary. When the lacrimal passages are involved in coloboma of the lids or facial cleft, reconstruction depends on the usable tissue of the lacrimal system. Treatment of connatal mucocele consists of digital expression of the pseudo-tumor. In cases of connatal dacryostenosis due to Hasner's membrane in infants, massage of the lacrimal sac as well as application of antibiotic eye drops and detumescent nose drops is indicated. After 5 or 6 months high-pressure irrigation with the hollow probe of Bangerter is necessary. Important is the postoperative treatment with detumescent and antibiotic eye drops as well as with detumescent nose drops for 1-2 weeks. In acute inflammation, treatment of the inflammation is the first goal of therapy, which may be combined with incision of the abscess. This can be performed by transcutaneous incision as well as by endonasal intervention in cooperation with a rhinologist.     

Visual impairment -- implications on health, costs and predictions for the future

Vision impairment in the elderly is significantly related to increased morbidity as well as mortality rates. Recent studies suggest the true costs associated with visual impairment and blindness to be much higher than reported previously. Without successful interventions the number of visually impaired or blind people world-wide will double within the next 20 years. The lack of a significant world-wide reduction in avoidable visual impairment and blindness would have substantial social as well as economical consequences. In contrast, three-quarters of all visual impairments are avoidable and therefore unnecessary. In summary, vision Impairment deserves a higher degree of attention by the public as well as from governments.     

Cataract Surgery and its Complications in Diabetic Patients

Abstract

Diabetic patients are known to have an increased risk of cataract development and cataract surgery is a common surgical procedure for diabetic individuals. Cataract extraction (CE) in diabetic patients as compared to non-diabetic patients is associated with higher risks of reported complications such as capsular contraction and opacification as well as post-surgical worsening of macular edema (ME) and diabetic retinopathy (DR). In this paper, we review the pathogenesis of diabetic cataract, the risk factors contributing to cataract complications as well as DR progression, and assess preventive measures and treatment options for DR and ME following CE.     

Specular microscopy--its clinical implications

Specular microscopy has multiple advantages in the clinical practice, allowing the study of the corneal endothelium in-vivo. We can observe corneal disorders, as well as the corneal status after intraocular surgery, of the posterior pole as well as of the anterior pole of the eye.