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Abstract: The gut microbiome plays a substantial immunologic and pathophysiologic role in maintaining the health of the host, and dysregulation of this dynamic ecosystem has been associated with several inflammatory conditions. Many studies have explored the influence of gut microbiota on the ocular surface and whether gut microbiota impact the pathophysiology of ophthalmic conditions. These findings have highlighted the advantages of enhancing gut microbes through probiotics, prebiotics, diet, vitamin supplementations, and fecal microbial transplant in clinical practice. The purpose of this review article was to provide an up-to-date overview of the knowledge on this topic. Further exploration of this area of research is important to help guide new therapeutic targets to develop treatment and prevention of certain ocular surface diseases., Competing Interests: The authors have no funding or conflicts of interest to disclose., (Copyright © 2022 Contact Lens Association of Ophthalmologists.)

Purpose of Review: To compile and report the ocular manifestations of coronavirus disease 2019 (COVID-19) infection and summarize the ocular side effects of investigational treatments of this disease., Recent Findings: Conjunctivitis is by far the most common ocular manifestation of COVID-19 with viral particles being isolated from tears/secretions of infected individuals. Multiple therapeutic options are being explored across a variety of medication classes with diverse ocular side effects., Summary: Eye care professionals must exercise caution, as conjunctivitis may be the presenting or sole finding of an active COVID-19 infection. While no currently studied therapeutic agents have been found to reliably treat COVID-19, early vaccination trials are progressing and show promise. A video abstract is available for a more detailed summary. VIDEO ABSTRACT: http://links.lww.com/COOP/A36.

Purpose of Review: To describe the VISION 2020: The Right to Sight, global initiative for the elimination of avoidable blindness, the contribution of glaucoma to the magnitude of global blindness and priorities going forward., Recent Findings: Although the target of the World Health Organization's Global Action Plan (2014-2019) has not been met in terms of 25% reduction in avoidable blindness, there is evidence that the contribution of glaucoma to blindness and vision impairment is reducing. Yet this focus on a threshold of visual acuity by which to measure prevalence underestimates the true burden of glaucoma. Recent population-based studies demonstrate the scale of the unmet need., Summary: Scaling up of integrated people-centered eye care, by embedding glaucoma detection and care pathways in health systems with a strong focus on primary healthcare, is necessary. Solutions include reinforcing existing pathways while emphasizing high-quality glaucoma care, in addition to novel solutions such as self-testing, digital portable technology, artificial intelligence, and multilevel care pathways that extend to the most underserved parts of the global community.

Purpose of Review: Toxic anterior segment syndrome (TASS) is a surgical complication resulting from a noninfectious inflammatory reaction to substances used during intraocular ophthalmic surgery. Continuous reporting of new information concerning risk factors and possible causes is critical for preventing this condition., Recent Findings: The diagnosis of TASS is clinical and its main features are well known. However, new causes of TASS are emerging and being reported, as are new treatment options for managing the inflammation or its complications, and prevention guidelines are being updated. This article presents current and novel information regarding these topics., Summary: Educating the medical community regarding potential causes of TASS and its prevention is necessary for improving management of TASS. Thorough investigations and reports of TASS cases are a fundamental step in achieving this goal. Still, as the complete eradication of TASS solely through prevention is unlikely, further studies regarding TASS's pathophysiology, systemic and ocular risk factors, and new treatment options are necessary.

Background: Negative orbit vector is defined as the most anterior globe portion protrudes past the malar eminence. The aim of the study was to evaluate the relationship between negative orbit vector and blow-out fracture location analyzing the distance between the anterior corneal surface and orbital bone with facial soft tissue in medial and orbital floor blow out fractures using orbital computed tomography (CT)., Methods: Seventy-seven patients diagnosed with blow-out fractures involving the medial or orbital floor were included. Distances from the anterior cornea to lower lid fat, inferior orbital wall, inferior orbital rim, and anterior cheek mass were measured using orbital CT scans. The proportion of negative orbit vector and measured distanced were compared between medial wall fracture and orbital floor fracture. Medical records including age, sex, concomitant ophthalmic diagnosis, and nature of injury were retrospectively reviewed., Results: Forty-three eyes from 43 patients diagnosed with medial wall fracture and 34 eyes from 34 patients diagnosed with orbital floor fracture were included. There was no significant difference in the distance from the anterior cornea to lower lid fat (P = 0.574), inferior orbital wall (P = 0.494), or orbital rim (P = 0.685). The distance from anterior cornea to anterior cheek mass was significantly different in medial wall fracture (-0.19 ± 3.49 mm) compared with orbital floor fracture (-1.69 ± 3.70 mm), P = 0.05. Negative orbit vector was significantly higher in orbital floor fracture patients (24 among 34 patients, 70.6%) compared with those with medial wall fractures (19 among 43 patients, 44.2%) (P = 0.04)., Conclusions: Patients presenting with a negative orbit vector relationship when the most anterior portion of globe protruded past the anterior cheek mass and malar eminence were more likely to develop orbital floor fracture than medial wall fracture.

Purpose: To recommend a standardized approach for measuring progress toward national goals to improve preschool children's eye health., Methods: A multidisciplinary panel of experts reviewed existing measures and national vision-related goals during a series of face-to-face meetings and conference calls. The panel used a consensus process, informed by existing data related to delivery of eye and non-eye services to preschool children., Results: Currently, providers of vision screening and eye examinations lack a system to provide national- or state-level estimates of the proportion of children who receive either a vision screening or an eye examination. The panel developed numerator and denominator definitions to measure rates of children "who completed a vision screening in a medical or community setting using a recommended method, or received an eye examination by an optometrist or ophthalmologist at least once between the ages of 36 to <72 months." A separate measure for children with neurodevelopmental disorders and measures for eye examination and follow-up were also developed. The panel recommended that these measures be implemented at national, state, and local levels., Conclusions: Standardized performance measures that include all eye services received by a child are needed at state and national levels to measure progress toward improving preschool children's eye health.

Purpose of Review: Posterior capsular rupture (PCR) and vitreous loss are inevitable complications encountered in cataract surgery across all levels of surgical experience and in spite of technological advances to improve safety. Thus, cataract surgeons must always be prepared to practice safe and effective intraoperative management strategies for capsular rupture., Recent Findings: Novel approaches for lens fragment removal, vitrectomy, and lens implantation have expanded the available options for cataract surgery in the setting of an open posterior capsule. Intraoperative PCR management strategies should prioritize safety and strive to minimize vitreous traction, stabilize anterior chamber volume, maintain capsular and zonular integrity, and protect the corneal endothelium and other anterior segment structures., Summary: With appropriate management of PCR and vitreous, surgeons may still deliver safe and satisfactory visual outcomes for modern cataract surgery.

Purpose: A national census survey of optometrists in Canada measured knowledge of ocular diseases associated with smoking cigarettes and current practice behaviors related to addressing tobacco use with patients, including prevention and cessation. Optometrists were also asked to identify tools to assist addressing tobacco use with patients., Methods: An online bilingual (English/French) survey was developed and an e-mail with a link to the survey was sent to all 4528 optometrists registered in Canada. No participation incentives were provided. Frequency data were tabulated for survey items. Logistic regression models were fit to understand respondent characteristics associated with discussing tobacco use prevention and cessation with patients., Results: The response rate was 19% (850 responses). Almost all respondents (98%) believed that smoking cigarettes was a risk factor for developing age-related macular degeneration; approximately half (55%) assessed the smoking status of patients during their initial visit; 7% reported that they discussed the benefits of tobacco use prevention with patients younger than 19 years; and 33% reported that they always or regularly assess their patients' interest in quitting smoking. Respondents who completed the survey in English were more likely (odds ratio, 2.4; 95% confidence interval, 1.01 to 5.65) to deliver prevention messaging, compared with respondents who completed the survey in French. Male respondents were less likely to assess patients' interest in quitting (odds ratio, 0.7; 95% confidence interval, 0.50 to 0.97) than female respondents. Most respondents (90%) were interested in a continuing education program about the impact of smoking on vision and eye health as well as strategies for discussing tobacco cessation and prevention., Conclusions: Optometrists are aware of the impact of smoking on ocular health; however, most respondents do not systematically engage in tobacco use prevention and cessation practices. Providing optometrists with tools, including continuing education, may help support patient conversations about the risks of tobacco use and improve public health.

Purpose: Most of the causes of childhood blindness are either treatable or preventable. Eye care-seeking behavior (ESB) of parents for their children plays a pivotal role in reducing this problem. This study was done because there was a sparsity of literature in this context and with a view to help eye care professionals plan better programs and to identify factors facilitating and/or hindering ESB of parents for their school-going children in an urban area., Methods: This study adopted a qualitative snapshot narrative study design. In-depth interviews and focus group discussions were conducted in areas of Chennai with parents and eye care professionals selected through stratified purposive sampling. Parents were based on those who sought care and did not seek care after a school eye screening program and on their socioeconomic status. Data were transcribed to English, familiarized, and inductive coded, and themes were formed. Redundancy was considered as end point of data collection., Results: Two focus group discussions and 11 in-depth interviews were conducted. Squint, redness or watering of eyes, eye irritation, headache, family history of ocular diseases, severity, and repetitiveness of symptoms facilitate parents seeking eye care for their wards/children. Economic status was an important barrier reported to affect the ESB. Logistic factors like taking appointment with doctor, taking leave from work, transport, and traveling distance were noted., Conclusions: This study shows the facilitating factors and barriers for ESB of the Chennai urban parents for their wards. The results suggest that efforts needed to be put to overcome the barriers through planned awareness programs.

Purpose of Review: To discuss the current preschool vision screening (PVS) guidelines and review some of the newest vision screening techniques. The different vision screening practices and barriers to screening are discussed., Recent Findings: Vision screening guidelines, which have been developed in response to the advances in technology and increased understanding of the developing visual system, have been recently updated by some of the major medical organizations that endorse vision screening. With advances in vision screening technology, there is a growing trend for screening at younger ages., Summary: PVS has been widely endorsed by various medical organizations as an effective way to detect preventable and treatable vision problems of childhood. Although PVS is widely recommended, actual screening rates remain low. There are several real and perceived barriers to screening which often prevents successful screening programs. Current vision screening guidelines take into account the recent advances in technology. With the development of new devices, vision screening can effectively be performed at younger ages.

Diabetic eye disease is a leading cause of vision loss and blindness in the United States and disproportionately affects Hispanics/Latinos. This article provides an overview of the Diabetes and Healthy Eyes Toolkit, a culturally and linguistically appropriate resource designed for community health workers to educate people with diabetes about eye health complications. The toolkit provides science-based, easy-to-understand information that can be used to conduct interactive, educational sessions about diabetes and eye health, the importance of comprehensive dilated eye examinations at least once a year for people with diabetes, and other ways to prevent vision loss and blindness.

Objectives: The human eye is exposed to toxic ultraviolet radiation (UVR) from sunlight and artificial sources. The UVR-induced damage occurs in ocular tissues from the corneal surface to the retina. Although the cornea and crystalline lens provide inherent UVR protection, the anterior ocular surface and the limbus, which contains stem cells, receive toxic levels of UVR from relatively short solar exposures., Methods: Shading headwear and some UVR-blocking sunglasses are designed to reduce direct solar exposure but may not protect the eye from diffuse ambient and surface reflected light. If the squint mechanism is reduced because of the reduction of visible light, the ocular surface is then exposed to ambient and reflected UVR. In addition, laterally incident radiation that is focused across the cornea onto the limbus, a phenomenon known as peripheral light focusing, can increase the dose at the nasal limbus by a factor of 20., Results: The UVR-blocking contact lenses that cover the limbus provide protection from all sources of ocularly incident UVR. Although directly relating solar UVR dose to ocular damage is epidemiologically challenging, irradiation of ocular cell cultures can estimate the toxic effects of UVR exposure. The use of UVR-blocking contact lenses greatly increases the time the wearer can be exposed to solar UVR before a toxic ocular dose is reached., Conclusions: There is a need for the development of a scientifically rigorous, clinically applicable ocular protection factor metric, based not only on the transmittance of eyewear but on the protection afforded from the total UVR field and the length of that exposure.

Objectives: Although the risks of excess solar ultraviolet (UV) exposure of the skin are well recognized, the need for eye protection is frequently overlooked, or when sunglasses are also recommended, specific guidance is wrong or is not explained. Guidance from the World Health Organization at its InterSun webpage advises people to wear "wrap-around" sunglasses under many conditions. The objective of this study was to examine the need for UV filtration in prescription lenses, contact lenses, and sunglasses., Methods: The geometry of UV exposure of both eyes, solar position, ground reflection, pupil size, and lid opening were studied. Because an accurate determination of cumulative ocular exposure is difficult, the cornea itself can serve as a biologic dosimeter, because photokeratitis is not experienced on a daily basis but does under certain ground-surface and sunlight conditions. From a knowledge of the UV-threshold dose required to produce photokeratitis, we have an upper level of routine ocular exposure to ambient UV., Results: From ambient UV measurements and observed photokeratitis, the upper limits of UV exposure of the crystalline lens or an intraocular lens implant are estimated. The risk of excess UV exposure of the germinative cells of the lens is greatest from the side. Sunglasses can actually increase UV exposure of the germinative region of the crystalline lens and the corneal limbus by disabling the eyes' natural protective mechanisms of lid closure and pupil constriction! The level of UV-A risk is difficult to define., Conclusions: Proper UV-absorbing contact lenses offer the best mode for filtering needless exposure of UV radiation of the lens and limbus.

It is well established that both acute and chronic ultraviolet (UV) exposure can lead to various ophthalmic pathologic conditions in the anterior segment. Several scientific studies have demonstrated that after UV exposure, the unprotected cornea is vulnerable to damage in the epithelial, stromal, and endothelial cellular layers. DNA damage, apoptosis, and altered protease expression are all examples of harmful changes that can occur within the cornea after irradiation. Beyond the cornea, damage associated with UV exposure, such as decreased antioxidant levels and increased reactive oxygen species production, has been noted in the aqueous humor and crystalline lens. Ultraviolet-blocking contact lenses have the potential to provide protection against such exposure to harmful UV radiation. Experimental use of UV-absorbing contact lenses prevented detrimental cellular changes to the cornea and maintained corneal clarity after UV exposure. Additionally, studies suggest that shielding the aqueous humor and crystalline lens from irradiation with UV-absorbing contact lenses aids in protection against precataractous changes. Despite ongoing research, to date, neither chronic nor clinical studies have been performed in humans to demonstrate that wearing UV-blocking contact lenses reduces the risk of developing cataracts or other ocular disorders within the anterior segment. This article will discuss the impact of UV exposure on ocular tissue and the need for adequate UV protection, with particular emphasis on UV-blocking contact lenses.

Over the last 30 years, many countries have developed strong sun protection programs, spurred on by rapidly increasing skin cancer incidence and concerns about stratospheric ozone depletion. More recently, considerable concern has arisen about widespread vitamin D insufficiency, creating a "sun exposure dilemma," since in most regions vitamin D predominantly derives from endogenous synthesis in the skin initiated by exposure to ultraviolet (UV) radiation. Little attention has been paid to whether a similar dilemma exists for UV-related eye conditions.For the eyes, to our current knowledge, exposure to UV radiation has only adverse effects. There is strong evidence that acute high dose exposure to UV radiation causes photokeratitis and photoconjunctivitis, while even low dose chronic exposure to UV radiation is a risk factor for cataract, pterygium, and squamous cell carcinoma of the cornea and conjunctiva. There is weaker evidence in relation to other conditions, including ocular melanoma and age-related macular degeneration. Ultraviolet radiation-related eye diseases are common, disabling, and cause a considerable disease burden worldwide.The "correct" public health message for optimal sun exposure is not clear cut, with too many variables-ambient UV radiation, personal skin type, age, weight, clothing habits, medication, and others-for a blanket sun safety message. In addition, there remain many unknowns, including strong evidence supporting or refuting the very many proposed health benefits of vitamin D. More evidence is required to define disease burdens for UV-induced eye diseases, to evaluate the decrease in disease burden from sun protective measures and to elucidate any beneficial effects of exposure of the eye to UV radiation, to provide appropriate advice to the public.

Purpose: To describe he role played by the United Nations Environmental Effects Panel with respect to the ocular effects of stratospheric ozone depletion and present the essence of the Health Chapter of the 2010 Assessment., Methods: A consideration of solar ultraviolet radiation (UVR) at the Earth's surface as it is affected by atmospheric changes and how these influence sunlight-related eye diseases. A review of the current Assessment with emphasis on pterygium, cataract, ocular melanoma, and age-related macular degeneration., Results: Although the ozone layer is projected to recover slowly in the coming decades, continuing vigilance is required regarding exposure to the sun. Evidence implicating solar UVR, especially UVB, in every tissue of the eye continues to be amassed., Conclusion: The need for ocular UV protection existed before the discovery of the depletion of the ozone layer and will continue even when the layer fully recovers in approximately 2100.

As the baby boom generation ages, it is anticipated that half a million cases per year will be added to the 19 to 21 million Americans not living in institutions or serving in the military who have low vision or blindness. The 4 major causes of vision loss and blindness in the United States are cataract, diabetic retinopathy, glaucoma, and age-related macular degeneration. All 4 diseases involve change in the microcirculation in eye structures. Holistic approaches to health incorporate attention to individuals' lifestyle choices. Relevant research literature was reviewed to identify strategies for lifestyle modification that nurses can use to prevent or slow progression of these diseases. Prevention strategies in general are those that promote avoidance of cardiovascular disease and diabetes. Because vision loss has been shown to be associated with diminished quality of life and increased mortality, lifestyle changes that prevent or moderate the impact of these diseases are an important focus of nursing care.

Community health centers (CHCs) have an impressive record of addressing health disparities through consistently delivering high-quality and affordable care in a culturally competent manner, while also producing cost savings to the nation's healthcare system. Thus CHCs are optimally positioned to reduce visual health disparities and improve visual health outcomes by being included in the primary care services that they deliver. An estimated three million health center patients have risk factors for vision disorders and eye disease, yet a recent policy briefing survey conducted by The George Washington University reported that about 20 percent of centers provide on-site eye and vision care.

Objectives: To assess the comfort and efficacy of epinastine 0.05% ophthalmic solution in contact lens wearers with a history of allergic conjunctivitis and contact lens intolerance during allergy season., Methods: One hundred forty-six subjects were enrolled in a multicenter, open-label study. Enrolled subjects instilled rewetting drops twice a day for a one-week run-in period, then were randomized to epinastine 0.05% twice a day plus rewetting drops as required (n = 75) or rewetting drops alone as required (minimum use twice a day) (n = 71). Subjects recorded the length of time that contact lens wear was comfortable, the total time of wear, ocular itch, overall comfort, and use of rewetting drops during the run-in period, at baseline, and on days 2 to 7 of the treatment period., Results: Subjects averaged 34 years of age; 79% were female. No significant differences were shown at baseline between subjects treated with epinastine 0.05% twice a day plus rewetting drops and control subjects treated with rewetting drops alone. Averaged over the treatment period, epinastine provided significant increases in comfortable wearing time (1.33 +/- 2.89 vs. 0.43 +/- 2.28 hr, P=0.012) and total wearing time (0.35 +/- 1.87 vs. -0.32 +/- 1.81 hr, P=0.008) compared with controls. Epinastine users reported less frequent additional rewetting drop use on average by 0.56 uses per day, which was significantly different than controls (reduction of 0.06 uses per day; P=0.012). Epinastine provided significantly greater improvements from baseline in ocular itch and overall eye comfort compared with rewetting drops alone (P

Objectives: Ocular complications after spine surgery are incompletely understood and are not as rare as implied by recent publications. In 13 out of 15 published case reports, ocular complications are attributed mainly to compression. But in 66 cases reported in 4 series in the literature, compression seems to play a role in less than 10 cases. However, 3 out of the 4 series lack sufficient detail to support this mechanism clearly. Our objectives were to identify the mechanisms and specific risk factors associated with this devastating complication, to help in prevention., Methods: A 2-page survey was sent to all French orthopedic centers specializing in spine surgery (28 centers) requesting information regarding any patients who had experienced visual deficits after spine surgery. Respondents were asked to identify presence of commonly cited preoperative risk factors, including ophthalmologic diagnosis and local signs (eyelid or conjunctival edema, periorbital numbness, or paresthesia) and intraoperative risks, such as positioning of the head, to clarify the possible mechanisms. Seventeen patients were thus included., Results: Two main mechanisms were identified. First, ocular compression (9 cases) characterized by a unilateral definitive blindness with local signs due to a central retinal artery occlusion. Second, internal carotid thromboembolism (4 cases) associated with head rotation toward the ipsilateral side, causing an ischemic optic neuropathy with a unilateral partial and potentially regressive visual loss., Conclusions: The authors propose 2 preventive measures: modification of horseshoe-shaped headrest and precautions with lateral rotation of the head in patients with carotid atheroma.

Every drug can produce untoward consequences, even when used according to standard or recommended methods of administration. Adverse drug reactions can involve every organ and system of the body, even the eye, and frequently are mistaken for signs of underlying disease. Reactions in the eye may involve the eyelids, periorbital tissues, lacrimal apparatus, conjunctiva, cornea, lens, iris, ciliary body, intraocular pressure, retina, optic nerve, and ocular movement. In addition, fetal abnormalities can be caused by the use of eye drugs during pregnancy. Topical ophthalmic therapies or the use of ophthalmic dyes may cause systemic reactions. This article reviews drugs used systemically or topically that may cause adverse effects in the eye and related structures. Adverse ocular reactions to medications create an important health problem, and nursing professionals in close contact with patients inside and outside the hospital must assume a role in detecting them early, identifying them, educating the patient about them, and treating them.

Purpose of Review: In a society with a steadily increasing population of patients with hypertension, a significant mortality risk factor, it is important that clinicians be cognizant of the changes seen in ophthalmic examination. This paper demonstrates both the acute and chronic stages of the disease., Recent Findings: This paper first presents the history of classifying different stages of hypertensive retinopathy, a condition associated with systemic arterial hypertension, as defined by Keith-Wagener-Barker. The most recent recommendations published in the Seventh Report of the Joint National Committee (JNC) on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure are also described; this report defines the current status and classification of hypertension in the United States, as well as recommendations for its treatment and management. Finally, disease management strategies and currently accepted treatment options are presented., Summary: Since systemic arterial hypertension is a key modifiable risk factor for various diseases such as myocardial infarction and stroke, it is crucial that we detect early signs of hypertension to promote better health for our patient population.

Burns to the eyelids occur in more than 20 percent of flame injuries and can lead to ocular damage and even blindness. Burn wound contracture can cause ectropion of the eyelid, resulting in exposure keratitis, corneal ulcers, and conjunctivitis. At our hospital, early eyelid release and grafting has made a significant difference in the long-term outcomes of third-degree eyelid burns; however, the question of just how early eyelid release and grafting should take place is an unresolved issue. Fifty-seven children with third-degree eyelid burns were reviewed; 17 had eyelid release within 7 days of receiving eyelid burns and 40 had a delay in eyelid release of more than 7 days after injury. Analysis was by chi-square with the Yates continuity correction or Fisher's exact test when appropriate. Corneal ulcers developed in 2 of 17 of the early eyelid release of third-degree burns, compared with 25 of 40 delayed releases (p = 0.001), exposure keratitis in 3 of 17 early releases, and 30 of 40 in delayed release (p = 0.000); conjunctivitis was identified in 1 of 17 early releases and 14 of 40 delayed eyelid releases (p = 0.025). Release of eyelid burns within 7 days of injury can prevent the development of exposure keratitis, progressive conjunctivitis, corneal ulceration, and the need for corneal surgery. We suggest that early release and grafting should be the treatment of choice for children and young adults with third-degree burns to the eyelids.

The ocular complications of diabetes mellitus are numerous and include retinopathy, cataract, uveitis, and neurophthalmic disorders. A review of the current literature shows that the emphasis has changed from the laser and surgical management of pre-existent retinopathy to the development of cohesive multidisciplinary screening and education programs, and to a better understanding of the cellular and molecular mechanisms that underlie disease. The role of associated and potentially modifiable systemic factors is also now recognized. Early intervention with systemic and local therapies may soon provide hope for the better management of diabetic eye disease.

Patients with carotid artery disease may present with monocular, ipsilateral ocular symptoms, and signs that can herald a devastating stroke. Asymptomatic retinal emboli, transient monocular visual loss, and central retinal artery occlusion are the most common. Venous stasis retinopathy and ocular ischemic syndrome are associated with severe hypoperfusion of the eye and usually reflect severe carotid occlusive disease. Embolic ischemic optic neuropathies and compression of the intracranial optic nerve by supraclinoid carotid arteries remain debated. Third-order Horner's syndrome and eye pain are common in carotid artery disease, particularly carotid dissection; carotid artery disease, however, is an uncommon cause of ocular motor nerve palsy. Several recent publications have highlighted the prognosis and management of patients with carotid artery occlusive disease, and have emphasized the role of the ophthalmologist in early diagnosis and prevention of further cerebral and systemic complications.

Lyme disease is a multisystem disorder caused by infection with the Borrelia burgdorferi spirochete. The diagnosis of Lyme disease usually is based on several clinical criteria, with supportive data from laboratory testing. The presence of the bullseye skin lesion, erythema migrans, is the single pathognomonic criterion. In the 20 years since the initial description of Lyme disease in the United States, B. burgdorferi has been implicated as an etiologic agent in numerous ophthalmic and neuro-ophthalmic syndromes, involving most structures from the cornea to the cranial nerves. Neuro-ophthalmic and ocular manifestations of Lyme disease include meningitis with papilledema, cranial neuropathies, follicular conjunctivitis, nummular keratitis, and intraocular inflammation. Although an association with Lyme disease has been purported for numerous other syndromes, a definite causal relationship has not been proved in many cases. During a period of rapidly increasing awareness of Lyme disease, a high index of suspicion and poorly defined criteria for its presence have resulted in over-diagnosis of Lyme disease. In the authors' experience, the incorrect diagnosis of Lyme disease initially has been made in patients with allergic conjunctivitis, keratoconus, morning glory syndrome, craniopharyngioma, meningioma, CNS lymphoma, paraneoplastic syndrome, multiple sclerosis, sarcoid, syphilis, and functional illness. Nevertheless, this treatable infection must be an important consideration in the differential diagnosis of certain ocular or neurologic diseases.

Ocular disease is a major component of the congenital rubella syndrome (CRS). Interest in this condition has been renewed after identification of a spectrum of delayed manifestations and the realization that sporadic cases of CRS will continue to occur despite vaccination programs due to reinfection in the immune patient. Work is continuing on strategies and planning of vaccination programs for disease prevention and control, refinements of diagnosis with particular emphasis on the prenatal diagnosis of fetal infection, and fundamental research into the pathogenic and immunologic mechanisms underlying CRS and its late manifestations.

The number of blind persons in the world is not accurately known. However, taking into account previous estimates by the World Health Organization and adjusting to the world population of 1990, it is likely that there are at least 35 million blind people if we apply the internationally accepted definition of blindness as vision less than 3/60 ( less than 20/400 or 0.05) in the better eye. If the threshold of vision less than 6/60 ( less than 20/200 or 0.1) is applied, the above figure can be increased by roughly 50%, ie, going well beyond 50 million blind people. To this somber picture should be added the effects of aging on populations in both developed and developing countries. Longer life expectancy is going to dramatically increase the need for eye care to prevent visual loss from such conditions as cataract, glaucoma, diabetic retinopathy, and macular degenerations. Corneal blindness, resulting mainly from trachoma and other infections, is apparently showing a downward trend, but there are still foci of severe disease. Thus the need for trichiasis surgery remains, and some recently evaluated techniques offer particularly good results. On the other hand, xerophthalmia due to vitamin A deficiency is still a major public health problem, causing both visual loss and increased mortality. It should be possible, by targeting ivermectin distribution programs to high-risk populations, to gradually eliminate onchocerciasis as a cause of blindness; however, the long-term sight-saving effect of ivermectin in cases of established ocular lesions needs to be confirmed.

Contact lenses can be a practical and visually efficient corrective modality in aqueous surface and subsurface environments. Even though contact lenses have many advantages for the ametropic individual, in certain situations there may also be disadvantages such as the risk of lens loss, ocular injury, or infection. In order to be able to wear contact lenses in these environments both prescribing practitioners and contact lens wearers must know when the risks of contact lens wear in these environments are minimal. In addition, they must know what precautions to take to minimize risks.

The intensities and spectra of ultraviolet and visible radiation were determined for different types of photofloods (575 to 5000 W) commonly used in television studios and theaters. The measurements were taken with a spectroradiometer at distances of 2.25, 4.5, or 10 m from the lamps. The measured spectral irradiance was weighted against biological hazard functions to determine the potential hazards. The results indicate that in television work, direct viewing of the light source should be limited to a few minutes per day to avoid potential photochemical injury to the retina. In addition, the luminances of the photofloods were calculated. Because the luminance of most of the tested photofloods was several orders of magnitude above the luminance level considered comfortable to the eyes, they can cause discomfort glare.

Optical materials that are available to the practitioner for protection of the eye against hazardous exposure to ultraviolet radiation (UVR) are discussed. Principles of protection, procedures for calculating safe ocular exposure duration, and transmittance curves of commonly prescribed spectacle lenses, contact lenses, and intraocular lenses are discussed. Suggestions are made to assist the practitioner in providing adequate protection for the patient.

The recent public concern regarding sunglass protection from UV energy has sparked a significant debate among those in the research community and industry. This debate grows out of concern for the known effects of UV energy in producing or contributing to eye effects such as keratitis, cataract formation, and retinal damage. The ANSI Z80.3 Standard addresses itself to this issue by setting levels of UV energy that are permitted to be transmitted in various labeling categories for over-the-counter sunlenses. One important issue is that the ANSI Standard does not provide for an absolute block of UV energy in any category of these lenses. Because the technology to provide this sort of total UV block is currently available, it is argued that there should be at least one category of lens that is fully protective in the UV range.

Advances in understanding the pathobiology of secondary complications after posterior segment penetrating ocular injuries along with progress in instrumentation and surgical techniques have provided a powerful means to salvage certain eyes that would otherwise be lost. Further progress will probably include the use of pharmacologic agents that interfere with fibrocellular proliferation, as well as better delineation of the methods and timing of surgery.

Individuals with dry eye symptoms cannot be excluded categorically from contact lens (CL) wear. Most patients with dry eye symptoms have a chronic disorder determined by genetics, age-related changes, or anatomic problems that interfere with blinking or the tear film. Furthermore, their symptoms may be exacerbated by drug use, environmental conditions, or the work they do. Although so-called "marginally" dry eyes usually provoke bothersome symptoms, they pose no real danger to ocular health, seldom require medical care, and are not an absolute contraindication to lens wear. Nevertheless, clinicians should conduct the appropriate tests to identify dry eye patients in the prefitting evaluation, so that potential problems in lens wear can be anticipated and addressed. The value of such testing cannot be overstated, as it is often possible to treat the underlying problem and thereby greatly minimize or even eliminate symptoms. This is particularly so when there is a drug, lens, or environmental component to the condition. Helpful approaches in CL wearers include blinking exercises, the use of wetting drops, or a modification of lens parameters (e.g., increased water content, larger diameter, and better edge design). Matching would-be lens wearers to the appropriate CL system is, of course, paramount.

Despite steady advances in surgical instrumentation and technique, ocular trauma continues to be a leading cause of visual loss in the United States. Almost half of the patients with posterior penetrating injuries are left with severe visual impairment. Controversy persists over the optimal management of the injured eye, including the proper use of prophylactic antibiotics, prophylactic cryopexy, and prophylactic scleral buckling. The role and timing of vitrectomy surgery in severe ocular trauma also remain topics of considerable debate, as does the role of vitrectomy in the management of magnetic intraocular foreign bodies. Each of these issues is discussed, with particular emphasis on conflicting views presented in the relevant literature.

The intravitreal infusion of thrombin at the time of retinectomy or retinotomy is an effective method of controlling hemorrhage from the cut edges of retina. Thrombin reduced the bleeding time from 118 +/- 24 seconds to 7 +/- 10 seconds following retinectomy. The intravitreal infusion of thrombin may possibly have an advantage over diathermy since less tissue destruction occurs.

We used an experimental model of proliferative vitreoretinopathy (PVR) and cell-induced traction retinal detachment to study the therapeutic value of six cytotoxic drugs (actinomycin C, colchicine, cytosine arabinoside hydrochloride, 5-fluorodeoxyuridine, vinblastine sulfate, and daunomycin). Pigmented rabbits were injected with 2.5 X 10(5) cultured homologous dermal fibroblasts. At the same time, cytotoxic drugs were injected into the vitreous in an attempt to inhibit cellular proliferation. The sensitivity of the cells to the drug was also tested in vitro before injection. Daunomycin at a dose of 10 nmol per eye stopped cellular proliferation and subsequent traction retinal detachment in vivo. The electroretinogram (ERG) showed no evidence of drug-induced retinal toxicity with this dose of daunomycin. No alteration in frequency or severity of vitreal membranes and retinal detachment was observed after injection of equivalent doses of the other drugs.