The conjunctival epithelium in dry eye subtypes: effect of preserved and non-preserved topical treatments

Preservatives in artificial tears: Assessing impact on dry eye symptoms: Findings from 67 951 questionnaire responses-Project FOREVER

PURPOSE

To examine the association between the presence of dry eye disease (DED) symptoms when using BAK-preserved artificial tears (AT) compared to preservative-free AT.

METHODS

In this cross-sectional study, we used data collected as part of Project 'Finding Ophthalmic Risk and Evaluating the Value of Eye exams and their predictive Reliability' (FOREVER). To analyse the strength and direction of associations, we used binomial logistic regression models adjusted for age, sex, smoking and eye diseases. The analysis was conducted on responses regarding AT formulations and seven distinct DED symptoms from 67 951 participants in Project FOREVER, including 8039 AT users.

RESULTS

Our analysis showed statistically significant higher odds ratios (ORs) of experiencing itching and blurred vision among users of BAK-preserved AT compared to preservative-free AT users, with ORs of 1.26 (95% CI 1.01-1.58) and 1.28 (95% CI 1.02-1.60), respectively. Additionally, a borderline significant trend indicated an increased number of DED symptoms in the BAK-preserved AT group compared to preservative-free AT users. Furthermore, our study provided a comprehensive overview of AT usage patterns within the cohort, illustrating the proportion of users for each type of AT.

CONCLUSION

Our findings suggest that BAK-preserved AT may worsen DED symptoms. We found higher ORs for experiencing itching and blurred vision as well as a tendency towards experiencing a higher number of symptoms when using BAK-preserved AT compared to preservative-free AT. Further longitudinal studies with additional questions on AT usage and clinical assessments are needed to validate these findings and optimize AT formulations for safer, effective DED management.

Overview of Dry Eye Disease for Primary Care Physicians

Dry eye disease (DED), also known as keratoconjunctivitis sicca, is a multifactorial ocular disease characterized by tear film insufficiency due to diverse etiologies including aging, incomplete and infrequent blinking, hormonal changes, medications, and systemic diseases. Classified into aqueous-deficient dry eye (ADDE), evaporative dry eye (EDE), and mixed subtypes, DED presents with symptoms such as irritation, stinging, redness, foreign body sensation, sensitivity to light, and blurred or fluctuating vision. While rare, severe cases may lead to vision loss. With its rising global prevalence across age groups, DED poses a significant public health challenge. Primary care physicians (PCPs), often the first point of contact for DED patients, require timely screening and management strategies. This review explores the epidemiology, pathophysiology, clinical manifestations, diagnosis, and management of DED, emphasizing practical approaches for PCPs. This narrative review was conducted by searching MEDLINE, PubMed, and Google Scholar databases for relevant articles. Diagnostic approaches, including detailed history taking, patient-reported questionnaires, differential diagnosis, and assessments are discussed alongside management strategies, including symptomatic ophthalmic treatment, risk factor mitigation (e.g., reduced digital device screen time), prevention, and nutrition. By providing a synopsis of early symptoms that PCPs are often the first to encounter, practical approaches to screening and managing DED in the primary care setting, and guidelines on when to refer to specialty care, this comprehensive review aims to equip PCPs with the knowledge to improve DED screening and optimize patient outcomes.

The Effect of High Molecular Weight Hyaluronic Acid and Latanoprost Eyedrops on Tear Functions and Ocular Surface Status in C57/BL6 Mice

Anti-glaucoma eye drop treatment often induces ocular surface problems, including dry eyes, and may be associated with poor medication compliance. This study aimed to investigate the effects of a novel high molecular weight hyaluronic acid and Latanoprost eye drop on intraocular pressure, as well as the tear function and ocular surface alterations in wild type mice, comparing the results with the mice receiving commercially available Latanoprost eye drops and mice receiving no treatment. The mice were divided into three groups: Group I, control group (no treatment group); Group II, commercial Latanoprost eye drop (LP); and Group III, Comfort Shield (CS) + Latanoprost (LP) eye drop (CS + LP). The CS + LP eye drop group had an IOP lowering effect comparable to the commercial LP eye drop group. The mice receiving LP eye drops had significantly worse corneal staining scores, lesser goblet cell density(GCD), higher numbers of CD45+ staining cells, significantly higher tear film concentrations of IL-6 and IL1-b, and a significantly lower expression of corneal ZO-1 mRNA compared with the mice receiving CS + LP 7 days after eye drop instillations (p < 0.05). In conclusion, the new CS + LP formulation appeared to induce less inflammation, less corneal vital staining, and a better barrier status with an IOP lowering effect comparable to the commercial LP eye drops.

Glaucoma and Ocular Surface Disease: More than Meets the Eye

Understanding the association between ocular surface disease and glaucoma is important for improving adherence to treatment and introducing practical solutions. While topical antihypertensive medications for glaucoma are well tolerated according to short-term studies, there is little evidence on their long-term effects. Since they are often required for many years, the effects of these drops on the ocular surface become important in regard to quality of life and adherence. In this nonsystematic review performed in April 2022, we summarize what is known about the relationship between glaucoma and ocular surface disease. Specifically, we examine how each class of topical glaucoma drops affects the ocular surface. We then review the treatment of ocular surface disease for patients on topical glaucoma therapy. Finally, we discuss treatments that may reduce or eliminate the burden of topical medications.

A Narrative Review of Ocular Surface Disease Related to Anti-Glaucomatous Medications

Topical anti-glaucomatous medications are still the most important measure to lower intraocular pressure. Large number of studies have confirmed that long-term use of anti-glaucomatous eye drops, especially containing benzalkonium chloride, a preservative, can cause or aggravate ocular surface injury. Ocular surface diseases damage the ocular microenvironmental health status, reduce the patients’ compliance with the treatment, and finally affect the treatment result. Therefore, the ocular surface management of patients with glaucoma is very important. This includes the selection of drugs that are better tolerated according to individual conditions, preservative-free formulations, drugs that protect against ocular surface disease, or selecting surgery and laser treatment, to prevent the damage to the ocular surface by topical anti-glaucomatous drugs.

Prevalence and Characteristics of Dry Eye Disease After Cataract Surgery: A Systematic Review and Meta-Analysis

Dry eye disease (DED) after cataract surgery is associated with various risk factors, while causing a wide range of heterogeneous symptoms including decreased quality of vision. This systematic review and meta-analysis aimed to determine the prevalence and characteristics of DED after cataract surgery. We searched PubMed and EMBASE and included studies on patients with DED after cataract surgery, between January 2011 and June 2020. Study-specific estimates (DED prevalence rates after cataract surgery in patients without preexisting DED) were combined using one-group meta-analysis in a random-effects model. We included 36 studies published between 2013 and 2020. We included nine of these in the meta-analysis of DED prevalence after cataract surgery. Overall 37.4% (95% CI 22.6-52.3; 206/775) of patients without preexisting DED developed DED after cataract surgery. The risk factors for DED after cataract surgery included age, female sex, systemic diseases, systemic medications, psychiatric conditions, preexisting DED, meibomian gland dysfunction, preservatives in eye drops, surgery techniques, and lifestyle. DED severity peak occurred 1 day postoperatively and persisted for at least 1-12 months following cataract surgery; therefore, consistent follow-up for DED is warranted for at least 1 month after cataract surgery. Topical administration of preservative-free diquafosol tetrasodium solution and preoperative meibomian gland treatment were effective in preventing and treating DED following cataract surgery. As more than one-third of patients develop DED after cataract surgery, careful DED management and treatment is needed after cataract surgery to improve satisfaction and vision quality.

Conjunctival impression cytology and tear-film changes in cases with vitamin D deficiency

PURPOSE

To evaluate conjunctival surface cells and tear-film functions in cases with vitamin D deficiency.

METHODS

Thirty-six patients with serum vitamin D deficiency and 27 control subjects with normal serum vitamin D levels were included in this prospective study. The tear break-up time (TBUT), Schirmer II test, and conjunctival impression cytology tests were performed to all participants.

RESULTS

The mean serum vitamin D levels were 10.5 ± 5.0 µl in the study group and 33.9 ± 11.7 µl in the control group (p < 0.001). The median TBUT scores were 11 s and 17 s and the median Schirmer II values were 7.5 mm and 12 mm in the study and the control groups, respectively (p = 0.003, p = 0.049). According to the Nelson staging system, 69.4% of the patients in the study group had grade 2 or 3 impression cytology, whereas 18.5% of the participants in the control group had grade 2 or 3 impression cytology (p < 0.001).

CONCLUSION

Our study results showed that vitamin D deficiency may lead to dry eye causing conjunctival squamous metaplasia and loss of goblet cells on the ocular surface.

The Effects of 3% Diquafosol Sodium Eye Drops on Tear Function and the Ocular Surface of Cu, Zn-Superoxide Dismutase-1 (Sod1) Knockout Mice Treated with Antiglaucoma Eye Medications

Anti-glaucoma eye drop treatment often induces dry eyes and can lead to poor medication adherence. This study aimed to investigate the effects of 3% diquafosol sodium eye drops on tear function and the ocular surface epithelium in Sod1^−/− mice after treatment with anti-glaucoma eye drops. The mice were divided into four groups: group 1, control group; group 2, anti-glaucoma eye drop; group 3, anti-glaucoma eye drops followed by a secretagogue eye drop (3% diquafosol); and group 4, simultaneous anti-glaucoma and secretagogue eye drop. Mice underwent assessments of tear quantity, tear film breakup time, and vital staining score. Mice in groups 3 and 4 showed significantly better tear stability and lower corneal staining scores than mice in group 2 after eye drop instillations (p < 0.05). Mice in group 4 showed significantly better tear stability, lower corneal staining scores, and higher goblet cell densities than those in group 1 after eye drop instillations (p < 0.05). The conjunctival epithelium showed stratification and abundance of Muc5AC-positive goblet cells in group 4, whereas thinning with desquamation was observed with a few goblet cells in group 2. Thus, simultaneous administration of 3% diquafosol sodium eye drops with topical anti-glaucoma drops showed favorable effects on tear stability and the corneal epithelium against the ocular surface toxicity inflicted by the anti-glaucoma eye drops.

Ocular surface toxicity from glaucoma topical medications and associated preservatives such as benzalkonium chloride (BAK)

INTRODUCTION

This review discusses the evidence concerning the effect of topical medications and their preservatives on the ocular surface in glaucoma patients. The role of topical anti-glaucoma medication remains critical in the management of chronic glaucoma worldwide but the beneficial effects of treatment are counterbalanced by the adverse effects of corneal and conjunctival toxicity. Areas covered: This article covers the effect of topical ocular drops and preservatives, particularly benzalkonium chloride, on the cornea and conjunctiva. Both basic science and clinical evidence will be presented. The first part reviews the relationship between ocular surface disease and benzalkonium chloride and the evidence from non-benzalkonium chloride preserved drops. The second part discusses the effects of benzalkonium chloride on the histopathology of the conjunctiva and its impact on clinical care as well as quality of life. Expert opinion: Topical anti-glaucoma medication will continue to be used in the management of this blinding disease for the foreseeable future. Treatment outcomes will benefit from minimized exposure to benzalkonium chloride. The development of alternative preservatives, preservative-free topical options, and non-drop therapeutics such as drug-eluting systems for the delivery of ocular medications, will be very helpful in the care of glaucoma patients.

Effectiveness and relevant factors of 2% rebamipide ophthalmic suspension treatment in dry eye

Background

Rebamipide with mucin secretagogue activity was recently approved for the treatment of dry eye. The efficacy and safety in the treatment of rebamipide were shown in two pivotal clinical trials. It was the aim of this study to evaluate the effect of 2 % rebamipide ophthalmic suspension in patients with dry eye and analyze relevant factors for favorable effects of rebamipide in clinical practice.

Methods

This was a retrospective cohort study of 48 eyes from 24 patients with dry eye treated with 2 % rebamipide ophthalmic suspension. Dry eye-related symptom score, tear film break-up time (TBUT), fluorescein ocular surface staining score (FOS) and the Schirmer test were used to collect the data from patients at baseline, and at 2, 4, 8, and 12 week visits. To determine the relevant factors, multiple regression analyses were then performed.

Results

Mean dry eye-related symptom score showed a significant improvement from the baseline (14.5 points) at 2, 4, 8 and 12 weeks (9.80, 7.04, 7.04 and 7.83 points, corrected P value <0.001, respectively). Median FOS showed a significant improvement from the baseline (3.0 points) at 2, 4, 8 and 12 weeks (2.0, 2.0, 1.0 and 1.0 points, corrected P value <0.001, respectively). TBUT and Schirmer test values were not significantly improved after the treatment. For ocular symptoms, three parameters (foreign body sensation, dry eye sensation and ocular discomfort) showed significant improvements at all visits. The multiple regression analyses showed that the fluorescein conjunctiva staining score was significantly correlated with the changes of dry eye-related symptom score at 12 weeks (P value = 0.017) and dry eye-related symptom score was significantly correlated with independent variables for the changes of FOS at 12 weeks (P value = 0.0097).

Conclusions

Two percent rebamipide ophthalmic suspension was an effective therapy for dry eye patients. Moreover the fluorescein conjunctiva staining score and dry eye-related symptom score might be good relevant factors for favorable effects of rebamipide.

Electronic supplementary material

The online version of this article (doi:10.1186/s12886-015-0040-0) contains supplementary material, which is available to authorized users.

Topical cyclosporine a for mustard gas induced ocular surface disorders

PURPOSE

To evaluate the effectiveness of topical cyclosporine A 0.05% for treatment of mustard gas-induced ocular surface disorders with special attention to conjunctival goblet cell density in patients with severe dry eye.

METHODS

This prospective clinical study included 20 eyes of 20 patients previously exposed to mustard gas with dry eye syndrome unresponsive to artificial tears. Before and after treatment with topical cyclosporine A 0.05% twice daily for 3 months, subjects were evaluated for improvement in symptoms using the ocular surface disease index (OSDI) and signs by tear breakup time (TBUT), Schirmer test and measurement of superior bulbar conjunctival goblet cell density. Limbal stem cell deficiency (LSCD) and the degree of corneal squamous cell metaplasia were also assessed before and after treatment.

RESULTS

Before treatment, mean OSDI score, Schirmer test I value and mean TBUT were 42.8 ± 6.1, 4.2 ± 1.2 mm and 2.5 ± 1.3 s, respectively. After 3 months of treatment with topical cyclosporine A, these scores reached 36.4 ± 5.2, 5.8 ± 1.6 mm and 4.9 ± 2.1 s, respectively showing a statistically significant improvement (P < 0.001) in all parameters. Mean goblet cell density was 23.3 ± 17.1/high power field (hpf) at baseline which was significantly increased to 47.7 ± 16.1/hpf at the end of the study (P < 0.001). There was no improvement, however, in corneal conjunctivalization, LSCD and the degree of corneal squamous cell metaplasia based on impression cytology reports (P > 0.05).

CONCLUSION

Treatment with topical cyclosporine A 0.05% in patients with severe dry eye due to mustard gas injury increases goblet cell density in the bulbar conjunctiva and improves symptoms of the disease.

Efficacy and Safety of Topical 0.05% Cyclosporine Eye Drops in the Treatment of Dry Eye Syndrome: A Systematic Review and Meta-analysis

A systematic review was performed to evaluate the safety and efficacy of topical 0.05% cyclosporine in treating patients with dry eye syndrome (DES). Twelve qualified randomized-controlled trials incorporating 1367 patients were analyzed. In comparison to controls, patients who were on topical 0.05% cyclosporine eye drops had lower Ocular Surface Disease Index scores (mean difference [MD]=4.10, 95% CI: 0.25-7.96, P=.04), longer tear film breakup time (MD=2.30 seconds, 95% CI: 0.75-3.86, P=.004), improved Schirmer I scores (MD=2.77 mm/5min, 95% CI: 1.63-3.91, P=.00001), reduced corneal fluorescein staining (standardized mean difference [SMD]=0.61, 95% CI: 0.07-1.15, P=.03), and higher goblet cell densities (SMD=1.68, 95% CI: 0.54-2.81, P=.004). However, there were more adverse effects in the cyclosporine patient group (odds ratio=1.64, 95% CI: 1.17-2.30, P=.004). Topical 0.05% cyclosporine eye drops twice daily significantly improved both the objective and subjective outcomes in DES patients. The study limitations in the clinical, methodological and statistical heterogeneities are discussed.

Ocular complications of diabetes mellitus

Diabetes mellitus (DM) is a important health problem that induces ernestful complications and it causes significant morbidity owing to specific microvascular complications such as, retinopathy, nephropathy and neuropathy, and macrovascular complications such as, ischaemic heart disease, and peripheral vasculopathy. It can affect children, young people and adults and is becoming more common. Ocular complications associated with DM are progressive and rapidly becoming the world's most significant cause of morbidity and are preventable with early detection and timely treatment. This review provides an overview of five main ocular complications associated with DM, diabetic retinopathy and papillopathy, cataract, glaucoma, and ocular surface diseases.

Topical cyclosporine A in the treatment of dry eye: a systematic review and meta-analysis

PURPOSE

Cyclosporine A (CsA) is considered a potentially effective treatment for dry eye syndrome (DES), which is now one of the most common ocular problems whose exact mechanism is unknown. Because randomized controlled trials (RCTs) reported to date have shown varying results in the efficacy and safety of CsA in different types of DES, we conducted a systematic review and meta-analysis of RCTs on CsA versus placebo in treating DES to evaluate the treatment efficacy and safety of CsA.

METHODS

We searched for RCTs published after 1990, in MEDLINE, EMBASE, the Cochrane library, and ClinicalTrials.gov. The RCTs that were included compared topical CsA and placebo for DES treatment by evaluating scores of ocular surface disease index, tear break-up time, or Schirmer test. Cochrane risk of bias tool was used for assessing the risk of bias.

RESULTS

We included 12 RCTs involving 3034 eyes of 1660 participants. We observed statistically significant improvements on scores of break-up time (standardized mean difference [SMD], 0.80; 95% confidence interval [CI], 0.13-1.46; I = 95%) and scores of Schirmer test with anesthesia (SMD, 0.78; 95% CI, 0.09-1.46; I = 97%) after treatment with topical CsA. Scores of ocular surface disease index (SMD, 0.77; 95% CI, -1.05 to 2.58; I = 98%) and scores of Schirmer test without anesthesia (SMD, 0.08; 95% CI, -0.11 to 0.27; I = 0%) were not improved. Adverse events (odds ratio [OR], 1.61; 95% CI, 1.28-2.02; I = 21%) were observed.

CONCLUSIONS

Topical CsA could be an effective treatment for DES, especially for DES associated with conjunctival injury. Further RCTs with larger sample sizes for different clinical types of DES are warranted to determine the efficacy and limitation for different clinical types of DES.

The effects of topical antiglaucoma drugs as monotherapy on the ocular surface: a prospective study

Purpose. The aim was to compare the effects of antiglaucoma eye drops on the tear functions and ocular surface. Method. Eighty-five eyes of 43 patients with glaucoma were included into this randomized prospective study. Timolol without preservative (1), timolol with benzododecinium bromide (2), latanoprost (3), bimatoprost (4), travoprost with benzalkonium chloride (5), and brimonidine with purite (6) were given to 6 groups. Schirmer I, tear film breakup time (TBUT), staining scores, and impression cytology samples were evaluated before and during 12-month-follow-up period. Results. At the end of 12 months, there was no detected change in Schirmer I and TBUT tests indicating dry eye. Corneal staining scores were higher in groups 1 and 2, while conjunctival staining scores were higher in group 6. Goblet cell count decreased in groups 1 and 5 in superior and inferior, group 2 in superior, and groups 3 and 6 in inferior conjunctiva. Squamous metaplasia grades showed a significant increase in groups 1 and 2 at 3rd, 6th, and 12th month controls (P < 0.05). Conclusion. We observed nonserious impact on tear functions and ocular surface with antiglaucoma monotherapy. Beta blockers induced more damage on the ocular surface suggesting the role of the dosing and active substances beside preservatives.

An update on dry eye disease molecular treatment: advances in drug pipelines

INTRODUCTION

Dry eye disease is a common disorder provoking changes in tear film and ocular surface. Untreated dry eye could cause ocular infections, corneal ulcer and blindness. Only a few drugs are authorized so far for the treatment of dry eye disease and the possibilities of evolution in this sector are immense. Consequently, a significant number of new potential solutions are under development or placed in the pharmaceutical pipeline, promising better results and lesser side effects.

AREAS COVERED

In this article, the corresponding literature and recent Phase III clinical trial data and the corresponding literature, for dry eye disease treatment are reviewed, revealing the new strategic movements in drug pipelines.

EXPERT OPINION

From the clinical trial results, the advancement in tear substitutes and secretagogues in addressing specific deficiencies of tear components even though not resolving the underlying conditions of the disease is evident. The vast majority of new compounds under development are anti-inflammatories, steroids, non-steroids and antibiotics; however, there are also some novel lubricating drops and mucin-tear secretagogues. A future aggressive therapy for dry eye, depending on the severity of the symptoms, would include combinations of soft steroids, anti-inflammatories, such as cyclosporine A, with the addition of the new polyvalent mucin and tear secretagogues.

An evidence-based analysis of Australian optometrists' dry eye practices

PURPOSE

The aims of this study were to investigate the clinical practices of Australian optometrists as related to the diagnosis, quantification, and management of dry eye and to assess whether these are consistent with research evidence and current guidelines.

METHODS

An online survey was distributed to registered optometrists (n = 654). Respondents provided information regarding their preferred diagnostic procedures and management strategies for dry eye, practice modality, year of commencing practice, and whether they possessed an interest in dry eye.

RESULTS

Respondents (n = 144) used multiple procedures for diagnosis. Recording patient symptoms ranked as the most important, most valuable, and most commonly used technique. The main objective tests were fluorescein-assisted tear breakup time, corneal fluorescein staining, and meibomian gland evaluation. Optometrists with an interest in dry eye more frequently used lissamine green, phenol red test, interference fringes, and tear osmolarity than nonspecialist practitioners. Dry eye treatment varied with severity. The mainstay of therapy was nonpreserved lubricants and eyelid hygiene; more practitioners recommended topical corticosteroids, systemic omega-3 fatty acid supplementation and increased dietary intake of omega-3 fatty acids for moderate and severe disease, respectively. The primary sources of information used to guide practitioners' management were derived from continuing education conferences.

CONCLUSIONS

This study indicates that although Australian optometrists use subjective and objective diagnostic tests and stratify treatment based on dry eye severity, there is a lack of uniformity regarding diagnostic testing, infrequent use of standardized grading scales, and significant variability in clinical care. These findings highlight the potential to improve the translation of dry eye research evidence and evidence-based guidelines into Australian optometric practice.

Recent developments on dry eye disease treatment compounds

Dry eye syndrome is a common tears and ocular surface multifactorial disease, described by changes in the ocular surface epithelia related to reduced tears quantity and ocular surface sensitivity, leading to inflammatory reaction. Managing the eye inflammation proved helpful to patients with dry eye disease and current treatment is based on the use of topically applied artificial tear products/lubricants, tear retention management, stimulation of tear secretion and using anti-inflammatory drugs. In this article we revise the corresponding literature and patents assembling the new treatment approaches of novel and future pharmaceutical compounds destined for the dry eye disease treatment. The most frequent categories of compounds presented are secretagogues and anti-inflammatory drugs. These compounds are the research outcome of novel therapeutic strategies designed to reduce key inflammatory pathways and restore healthy tear film.

Acupuncture for dry eye syndrome after refractive surgery: study protocol for a randomized controlled trial

BACKGROUND

Dry eye syndrome is a frequent complication of refractive surgery. Acupuncture has been widely used to alleviate the associated symptoms. However, the use of acupuncture for patients who suffer from dry eye syndrome following refractive surgery has certain drawbacks. This pilot study aims to evaluate the efficacy of acupuncture treatment in treating the signs and symptoms of dry eye syndrome after refractive surgery.

METHODS/DESIGN

Forty participants will be randomly assigned to the acupuncture plus usual care group or the usual care control group. The acupuncture plus usual care group will undergo treatments on seventeen acupuncture points, three times per week for four weeks. The control group will receive only usual care during the same period. The primary outcomes will be scores on the Ocular Surface Disease Index (OSDI) and the results of examinations at 1, 3, 5, and 13 weeks. The secondary outcomes will be Tear Film Break-up Time (TBUT), as well as scores on the Schirmer-I test, visual analog scale (VAS), and quality of life (QOL) questionnaire for the self-assessment of ocular discomfort. Digital photographs will be taken to document the pattern of fluorescein staining observed on the corneal surface. The results of the Schirmer-I test, TBUT, and fluorescein-stained corneal surface digital photographs will be assessed at the screening and at week 13. VAS scores will be assessed at the screening, as well as at 1, 3, 5, and 13 weeks. QOL will be evaluated at 1, 3, 5, and 13 weeks.

DISCUSSION

This trial will provide primary data with which to investigate the clinical effectiveness and safety of acupuncture treatment for dry eye syndrome after refractive surgery.

TRIAL REGISTRATION

Current Controlled (Identifier: KCT0000727).

Short-term effect of topical brinzolamide-timolol fixed combination on ocular surface of glaucoma patients

AIM

To evaluate the short-term effect of the fixed combination of brinzolamide-timolol on the ocular surface in glaucoma patients.

METHODS

This is a prospective study of 23 eyes of 23 patients with newly diagnosed glaucoma. Schirmer I test, tear break-up time (BUT) measurement, conjunctival impression cytology and central corneal thickness (CCT) measurements were performed in one of the eyes of each patients before and 4 weeks after brinzolamide-timolol fixed combination therapy. All patients were asked to answer the OSDI questionnaire form about the ocular surface symptoms at baseline and at 1 week and 4 weeks follow-up visits.

RESULTS

After brinzolamide-timolol fixed combination theraphy Schirmer I, BUT and CCT values decreased but the only statistically significant decrease was seen in BUT test (P=0.03). OSDI scores increased during the follow-up but this increase was not statistically significant (P=0.22, P=0.42 respectively). Impression cytology findings ranged from 0.78±0.42 to 0.95±0.36 according to the Nelson classification. There was no statistically significant difference between baseline and 4 weeks follow up in impression cytology grades (P=0.15).

CONCLUSION

The results of our study indicate that short-term use of brinzolamide-timolol fixed combination theraphy does not have a profound effect on ocular surface except BUT values.

Goblet cells of the normal human bulbar conjunctiva and their assessment by impression cytology sampling

Goblet cells of the conjunctiva are the main source of mucus for the ocular surface. The objectives of this review are to consider the goblet cells as assessed by various histological, cytological and electron microscopy methods, and to assess the consistency of published reports (over more than 25 years) of goblet cell density (GCD) from impression cytology specimens from nominally healthy human subjects. Reported GCD values have been notably variable, with a range from 24 to 2226 cells/mm² for average values. Data analysis suggests that a high density of goblet cells should be expected for the healthy human conjunctiva, with a tendency toward higher values in samples taken from normally covered locations (inferior and superior bulbar conjunctiva) of the open eye (at 973 +/- 789 cells/ mm²) than in samples taken from exposed (interpalpebral) locations (at 427 +/- 376 cells/mm²). No obvious change in GCD was found with respect to age, perhaps because the variability of the data did not allow detection of any age-related decline in GCD. Analyses of published data from 33 other sources indicated a trend for GCD to be lower than normal across a spectrum of ocular surface diseases.

Effects of topical cyclosporine a plus artificial tears versus artificial tears treatment on conjunctival goblet cell density in dysfunctional tear syndrome

OBJECTIVES

The aim was to compare the effects of topical cyclosporine A and artificial tears combination with artificial tears alone in patients with dysfunctional tear syndrome (DTS).

METHODS

Forty-two eyes of 42 patients with DTS were enrolled in the study. The inclusion criteria for the study were Schirmer I (without anesthesia) scores below 10 mm/5 min and tear film break-up time (BUT) below 10 sec. The patients were randomly divided into two groups. The study group (22 patients) underwent 0.05% cyclosporine A treatment twice a day and preservative-free artificial tears for four times a day for 4 months. The control group (20 patients) was administered only preservative-free artificial tears four times a day for 4 months. The BUT, Schirmer test scores, corneal fluorescein staining, conjunctival lissamine green staining, and goblet cell density derived by impression cytology were recorded before and after treatment in each group.

RESULTS

In the study group, all parameters improved statistically significantly after treatment at the 4-month follow-up compared with the pretreatment values (P<0.001 for all). In the control group, corneal fluorescein staining (P<0.001) and conjunctival lissamine green staining (P=0.014) improved, but BUT and Schirmer scores did not change significantly after treatment. At the end of the 4-month follow-up, the study group demonstrated statistically significantly better BUT (P=0.020), Schirmer scores (P=0.002), goblet cell density (P=0.006), corneal fluorescein staining (P=0.003), and conjunctival lissamine green staining (P=0.017) scores than did the control group.

CONCLUSIONS

Topical cyclosporine A and artificial tears treatment significantly increases goblet cell density, decreases the signs of DTS, and improves ocular surface health.

Effects of common topical antiglaucoma medications on the ocular surface, eyelids and periorbital tissue

Glaucoma affects millions of people around the world. With the baby boom generation aging, the number of people affected by primary open-angle glaucoma in the US is expected to reach 3.3 million by 2020, and about half may not know they have the disease. The treatment of most forms of glaucoma includes the use of topical agents that enhance aqueous humour outflow, reduce aqueous production, or both. Topical intraocular pressure-lowering drugs must penetrate across the tissues of the eye to reach their therapeutic targets. Often, these tissues show the first signs and symptoms of drug toxicity and adverse effects. These include eyelid dermatitis, malpositions, lacrimal system scarring, ocular discomfort upon instillation, tear film instability, conjunctival inflammation, subconjunctival fibrosis, conjunctival epithelium changes, and corneal surface and endothelial impairment. For these reasons, ophthalmologists should evaluate the risks and benefits of ophthalmic medications before initiating therapy, identify the minimum dosages necessary to achieve a therapeutic benefit, and monitor patients for local and systemic adverse effects. Adverse events may be reduced by changing to a different class of topical medication, using corticosteroids, lubricating the eyes frequently, and reducing exposure to preservatives. This in turn can lead to higher levels of adherence to antiglaucoma therapy, improved outcomes and a reduction in the costs associated with long-term glaucoma complications. This article reviews the ocular adverse effects associated with the various classes of topical antiglaucoma drugs, with a particular focus on the ocular surface, eyelids and periorbital tissue.

Effect of lacrimal plugs combined with deproteinized calf blood extract eye gel for filamentary keratitis

This study aims to investigate the efficacy of lacrimal plugs combined with deproteinized calf blood extract eye gel on the treatment of dry-eye-associated filamentary keratitis. Lacrimal plugs were inserted into both the upper and lower puncta of 15 patients (28 eyes). Deproteinized calf blood cxtract eye gel was applied in two patients who were not cured after this operation. All patients were asked to complete three questionnaires 1 day before the surgery and at 1 week and 1 month after the surgery. Ophthalmologic examinations were carried out and repeated at 1 day and at 1 week and 1 month after plug insertion, which include fluorescein staining, tear break-up time (BUT), Schirmer test I (STI), corneal confocal microscope (HRT-III), and impression cytology (IC). Symptoms were relieved in all patients 1 month after the application of lacrimal plugs. Deproteinized calf blood extract eye gel was applied to two patients whose symptoms remained after lacrimal plug implantation for 1 week. At 3 weeks later, the symptoms disappeared and cornea fluorescein stain was hardly identified. The lacrimal river in all patients became broader after the surgery, 11 of whom reached 0.3 mm. Cornea filamentary disappeared in all patients. The average of BUT and ST were increased to 7.50 ± 1.897 s (p < 0.001) and 8.12 ± 1.996 mm at 1 week after the operation and 7.94 s and 9.00 ± 1.897 mm at 1 month later, respectively. Photography from HRT-III suggested that the state of corneal epithelium was markedly improved, including the squamous metaplasia of the epithelial layer of the cornea and the bend of nerve fibers under the corneal epithelium. IC also suggested that the squamous metaplasia of epithelial layer of conjunctiva in these patients was improved. The symptoms of patients suffering from severe filamentary keratitis were remarkably relieved by using lacrimal plugs, which could increase the tear volume of the ocular surface, improve the condition of tear film, and promote the recovery of corneal diseases. For patients with more severe symptoms, additional usage of deproteinized calf blood extract eye gel could assist the treatment. Therefore, lacrimal plugs combined with deproteinized calf blood extract eye gel are suggested to be an effective method to treat severe filamentary keratitis.

Advancements in anti-inflammatory therapy for dry eye syndrome

PURPOSE

The goal of this literature review is to discuss recent discoveries in the pathophysiology of dry eye and the subsequent evolution of diagnostic and management techniques. The mechanisms of various anti-inflammatory treatments are reviewed, and the efficacy of common pharmacologic agents is assessed. Anti-inflammatory therapy is evaluated in terms of its primary indications, target population, and utility within a clinical setting.

METHODS

The Medline PubMed database and the World Wide Web were searched for current information regarding dry eye prevalence, pathogenesis, diagnosis, and management. After an analysis of the literature, major concepts were integrated to generate an updated portrayal of the status of dry eye syndrome.

RESULTS

Inflammation appears to play a key role in perpetuating and sustaining dry eye. Discoveries of inflammatory markers found within the corneal and conjunctival epithelium of dry eye patients have triggered recent advancements in therapy. Pharmacologic anti-inflammatory therapy for dry eye includes 2 major categories: corticosteroids and immunomodulatory agents. Fatty acid and androgen supplementation and oral antibiotics have also shown promise in dry eye therapy because of their anti-inflammatory effects.

CONCLUSIONS

Anti-inflammatory pharmacologic agents have shown great success in patients with moderate to severe dry eye when compared with alternative treatment modalities. A deeper understanding of the link between inflammation and dry eye validates the utilization of anti-inflammatory therapy in everyday optometric practice.

Tolerability and effectiveness of preservative-free dorzolamide-timolol (preservative-free COSOPT) in patients with open-angle glaucoma or ocular hypertension

PURPOSE

To assess the effect of preservative-free dorzolamide-timolol on nonvisual symptoms and intraocular pressure (IOP) in newly diagnosed and untreated patients with open-angle glaucoma or ocular hypertension.

METHODS

This was a prospective, 8-week, open-label, Canadian multicenter study. All patients were treated with preservative-free dorzolamide-timolol formulation. The primary outcome was the change in the nonvisual symptom score of the Glaucoma Symptom Scale (GSS-SYMP-6) from baseline to 8 weeks. Secondary effectiveness outcome measures were absolute and percent changes in IOP from baseline to 4 and 8 weeks.

RESULTS

One hundred and seventy-eight patients were enrolled. Mean (SD) age was 65.6 (12.1) years and 90 (50.6%) were females. There were 92 patients diagnosed with open-angle glaucoma, 62 with ocular hypertension, and 23 with both diseases (diagnosis was missing for one patient). The mean (SD) GSS-SYMP-6 score increased from 73.6 (21.8) at baseline to 76.1 (20.7) at 8 weeks (P = 0.097). Mean (SD) IOP significantly decreased by 11.7 (5.1) mmHg at 4 weeks (P < 0.001) and by 11.5 (5.3) mmHg at 8 weeks (P < 0.001), representing reductions of -38.5% (P < 0.001) and -38.0% (P < 0.001), respectively.

CONCLUSION

Preservative-free dorzolamide-timolol does not increase eye discomfort while significantly reducing IOP in patients with open-angle glaucoma or ocular-hypertension.

Acupuncture for dry eye: a randomised controlled trial protocol

BACKGROUND

Dry eye is usually managed by conventional medical interventions such as artificial tears, anti-inflammatory drugs and surgical treatment. However, since dry eye is one of the most frequent ophthalmologic disorders, safer and more effective methods for its treatment are necessary, especially for vulnerable patients. Acupuncture has been widely used to treat patients with dry eye. Our aim is to evaluate the effectiveness and safety of acupuncture for this condition.

METHODS/DESIGN

A randomised, patient-assessor blinded, sham (non-acupuncture point, shallow acupuncture) controlled study was established. Participants allocated to verum acupuncture and sham acupuncture groups will be treated three times weekly for three weeks for a total of nine sessions per participant. Seventeen points (GV23; bilateral BL2, GB4, TE23, Ex1 (Taiyang), ST1 and GB20; and left SP3, LU9, LU10 and HT8 for men, right for women) have been selected for the verum acupuncture; for the sham acupuncture, points have been selected that do not coincide with a classical acupuncture point and that are located close to the verum points, except in the case of the rim of the eye. Ocular surface disease index, tear film breakup time, the Schirmer I test, medication quantification scale and general assessment of improvement will be used as outcome variables for evaluating the effectiveness of acupuncture. Safety will also be assessed at every visit. Primary and secondary outcomes will be assessed four weeks after screening. All statistical analyses will be performed using analysis of covariance.

DISCUSSION

The results of this trial will be used as a basis for clarifying the efficacy of acupuncture for dry eye.

TRIAL REGISTRATION

ClinicalTrials.gov NCT00969280.

Impression cytology: recent advances and applications in dry eye disease

Impression cytology (IC) allows cells to be harvested from the ocular surface noninvasively. Superficial layers of the epithelium are removed by application of cellulose acetate filters or Biopore membranes, and the cells can be subsequently analyzed by various methods, depending on the objective of the investigation or pathology involved. IC techniques are easily learned, can be performed in an outpatient setting, and cause virtually no discomfort to the patient. IC facilitates the diagnosis of ocular surface disorders, including, among others, keratoconjunctivitis sicca, ocular surface squamous neoplasia, and ocular surface infections. During the past decade, IC has been used increasingly to assist in diagnosis of ocular surface disease, improve our understanding of the pathophysiology of ocular surface disease, and provide biomarkers to be used as outcome measures in clinical trials. Dry eye disease is one area in which IC has contributed to significant advances.

Concordance between common dry eye diagnostic tests

AIM

Large variations in results of diagnostic tests for mild to moderate dry eye are widely recognised. The purpose of this study was to assess if there was concordance between common dry eye diagnostic tests.

METHODS

A total of 91 subjects were recruited to the study. The tear film and ocular surface were evaluated using the phenol red thread test (PRT), tear film break-up time (TBUT), biomicroscopic examination and impression cytological assessment of conjunctival goblet cells. Dry eye symptoms were assessed using McMonnies' dry eye questionnaire (MQ) and statistical correlations between all tests were assessed.

RESULTS

This study cohort did not include severe aqueous deficient dry eye patients as determined by the PRT. A statistically significant difference was noted between PRT results and all other tests (p

CONCLUSION

A correlation was found only between tests assessing lipid/mucous deficiency (Meibomian gland evaluation, goblet cell density, TBUT and MQ).

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Key Words

• correlation dry eye diagnostic tests

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MESH Headings

• Adult
• Aged
• Aged, 80 and over
• Analysis of Variance
• Conjunctiva/pathology
• Diagnosis, Differential
• Diagnostic Techniques, Ophthalmological/standards
• Dry Eye Syndromes/diagnosis
• Female
• Humans
• Male
• Meibomian Glands/pathology
• Middle Aged
• Reproducibility of Results
• Tears/metabolism
• Young Adult

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Grants

• R01 EY019470 NEI NIH HHS

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Affiliation(s)

J E Moore Centre for Molecular Biosciences, University of Ulster, Cromore Road, Coleraine, Northern Ireland BT52 1SA, UK.
J E Graham
E A Goodall
D A Dartt
A Leccisotti
V E McGilligan
T C B Moore

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Collaborators Collapse

Detrimental effect of preservatives in eyedrops: implications for the treatment of glaucoma

Antiglaucoma medications are often associated with ocular adverse reactions such as dry eye, and burning or stinging sensations. These undesirable effects may lead to treatment discontinuation and reduced quality of life in patients with glaucoma. Antiglaucoma medications usually contain benzalkonium chloride (BAK) as a preservative. Animal studies, in vitro studies and in vivo experiments have demonstrated various adverse effects of BAK. Clinical studies have also shown an increased incidence of adverse events with BAK and have demonstrated that the withdrawal of preservatives reduces these effects. Collectively, these data suggest that preservative-free antiglaucoma treatments have clinically relevant benefits for patients.

Effects of sequential artificial tear and cyclosporine emulsion therapy on conjunctival goblet cell density and transforming growth factor-beta2 production

PURPOSE

To evaluate the effects of sequential treatment with artificial tears and cyclosporine emulsion on conjunctival goblet cell density and production of transforming growth factor (TGF)-beta2 in patients with dry eye disease.

METHODS

Patients with dry eye disease (N = 6) defined by an Ocular Surface Disease Index symptom score >or=25, Schirmer test 1 <10 mm, and corneal fluorescein and conjunctival lissamine green staining scores >or=3 were treated with artificial tears (Refresh Plus; Allergan, Irvine, CA) 4 times a day for 4 weeks, followed by 0.05% cyclosporine emulsion (Restasis; Allergan) twice a day for 12 weeks. Impression cytology was performed on the bulbar conjunctiva of both eyes at baseline, after artificial tear therapy, and after 6 and 12 weeks of cyclosporine therapy. Goblet cells were counted in 5 representative microscopic fields per membrane in those taken from the temporal and inferior bulbar conjunctiva of the worse eye, and membranes taken from the fellow eye were immunostained for TGF-beta2.

RESULTS

There were no differences in mean goblet cell density between baseline and 4 weeks of artificial tears in the temporal and inferior bulbar specimens. After 6 weeks of cyclosporine emulsion, goblet cell density was significantly greater than baseline and artificial tears in the inferior bulbar conjunctiva (P < 0.01). After 12 weeks of cyclosporine emulsion, goblet cell density was significantly greater than baseline and artificial tears in both temporal and inferior bulbar sites (P < 0.01). The number of TGF-beta2-positive goblet cells was also noted to increase after 6 and 12 weeks of cyclosporine therapy (P < 0.001).

CONCLUSIONS

Cyclosporine emulsion, but not artificial tears, increases goblet cell density and production of the immunoregulatory factor TGF-beta2 in the bulbar conjunctiva in patients with dry eye.

Nucleus and cell size changes in human bulbar conjunctival cells after soft contact lens wear, as assessed by impression cytology

PURPOSE

To specifically assess the nucleus size and its relationship to cell size for human bulbar conjunctival cells.

METHODS

Impression cytology samples were taken from the nasal side of the intra-palpebral zone of the bulbar conjunctival surface from 20 young adult white European males, half of whom were successful daily soft contact lens wearers. A Millcell-CM filter was used, after topical anaesthesia with oxybuprocaine 0.4%, which was stained with Giemsa and colour images taken at 400x magnification by light microscopy. The images were graded and also a 35mm was prepared. From the projected image, an overlay method was used to outline the borders such that the cell and nucleus areas could be measured by planimetry.

RESULTS

The group mean cell area values were 267+/-59microm(2) (n=10, +/-S.D.) and 1028+/-357microm(2) for the non-contact lens wearers and contact lens wearers, respectively. The cell nucleus areas were 64+/-11microm(2) and 99+/-19microm(2), respectively. Both the cell areas and nucleus area values were statistically different between the two groups (p<0.001).

CONCLUSIONS

These studies confirm that soft contact lens wear can result in cell enlargement (squamous metaplasia) of the bulbar conjunctival cells. With this cell enlargement, the nucleus-to-cytoplasm ratio also changes, but the nucleus size generally increases (rather than decreases).

Research in Dry Eye: Report of the Research Subcommittee of the International Dry Eye WorkShop (2007)

Members of the DEWS Research Subcommittee reviewed research into the basic mechanisms underlying dry eye disease. Evidence was evaluated concerning the tear film, lacrimal gland and accessory lacrimal glands, ocular surface epithelia (including cornea and conjunctiva), meibomian glands, lacrimal duct system and the immune system. Consideration was given to both animal and human research data. Results are presented as a series of information matrices, identifying what is known and providing supporting references. An attempt is made to identify areas for further investigation.

Management and Therapy of Dry Eye Disease: Report of the Management and Therapy Subcommittee of the International Dry Eye WorkShop (2007)

The members of the Management and Therapy Subcommittee assessed current dry eye therapies. Each member wrote a succinct evidence-based review on an assigned aspect of the topic, and the final report was written after review by and with consensus of all subcommittee members and the entire Dry Eye WorkShop membership. In addition to its own review of the literature, the Subcommittee reviewed the Dry Eye Preferred Practice Patterns of the American Academy of Ophthalmology and the International Task Force (ITF) Delphi Panel on Dry Eye. The Subcommittee favored the approach taken by the ITF, whose recommended treatments were based on level of disease severity. the recommendations of the Subcommittee are based on a modification of the ITF severity grading scheme, and suggested treatments were chosen from a menu of therapies for which evidence of therapeutic effect had been presented.

Increasing importance of dry eye syndrome and the ideal artificial tear: consensus views from a roundtable discussion

BACKGROUND

Dry eye syndrome is a highly prevalent, yet largely under diagnosed, condition that can substantially affect quality of life. Left untreated, dry eye is associated with chronic eye pain and increased risk of ocular surface disease. Current demographic changes and lifestyle factors indicate that the dry eye syndrome patient population will increase significantly, ensuring that general practitioners and ophthalmic clinicians alike will experience more patients presenting with dry eye symptoms. Greater public and practitioner awareness of emerging research, technologies, and therapies is crucial to ensuring appropriate interventions to meet specific patient needs and result in clinically favorable outcomes.

ROUNDTABLE ASSEMBLY

In August 2005, a team of ocular surface experts convened for a 1-day roundtable session to discuss the latest information on diagnosing and treating dry eye syndrome and real-world issues in artificial tear therapy, including preservative use.

ROUNDTABLE DISCUSSION

The discussion centered on the mild to moderate dry eye patient and critical features of the ideal artificial tear, which are preservative-free formulation, protection from microbial contamination, cost-effective, non-blurring, and easy to use. Products that match this profile have the advantage of being able to benefit the myriad of patients who comprise the dry eye syndrome population. Ocular surface health should always remain a top priority. Preferred Practice Pattern Dry Eye Syndrome Medical Treatment guidelines should be modified to recommend the use of preservative-free formula artificial tear products for all levels of dry eye conditions in consideration of the medical benefit they offer to dry eye syndrome sufferers.

CONCLUSION

The growing prevalence of dry eye syndrome demands increased attention. Further research, enhanced diagnostic tests, increased use of preservative-free artificial tear formulations as first-line therapy, greater patient-practitioner interaction, and patient education are warranted.

Comparison of Toxicological Profiles of Benzalkonium Chloride and Polyquaternium-1: An Experimental Study

PURPOSE

The aim of this study was to compare, in vivo on a rat model, two different preservatives- benzalkonium chloride (BAC) and polyquaternium-1 (PQ-1)-using new experimental approaches.

METHODS

Thirty (30) eyes of 15 male Lewis rats were used in this study. Rats were randomly divided into five groups instilled twice a day for 11 days with eye drops containing different concentrations of preservatives, 0.1% BAC, 0.5% BAC, 0.1% PQ-1, 0.5% PQ-1, and balanced salt solution (BSS) as a control. The ocular surface toxicity of these two preservatives was investigated using new in vivo experimental approaches. Slit-lamp examination, the fluorescein test, the red phenol test, impression cytology, and in vivo corneal confocal microscopy were used to evaluate the rat ocular surface after preservative instillation. Histology sections and immunohistochemistry were also examined to confirm these results.

RESULTS

Compared to PQ-1, BAC consistently and dramatically altered the corneoconjunctival surface as evaluated by slit-lamp examination, the fluorescein test, impression cytology, in vivo confocal microscopy, and histology. The 0.5% BAC solution also significantly decreased tear production compared to the control. Although 0.5% PQ-1 significantly decreased goblet cell density in comparison to the control, and some abnormalities were observed with in vivo confocal microscopy, no statistically significant differences were observed between these two groups using the tear production test, slit-lamp and fluorescein evaluation, or histology.

CONCLUSION

Using an acute rat model of ocular toxicity by comparing preservatives at high concentrations, we demonstrated in vivo that high doses of PQ-1 were much less toxic than BAC. In vivo confocal microscopy and impression cytology are new promising experimental approaches to studying the rat corneoconjunctival surface, particularly in the field of ocular surface toxicity.

Conjunctival impression cytology in dogs

OBJECTIVE

Ocular conjunctivas of healthy dogs were studied by conjunctival impression cytology for evaluation of feasibility, protocol standardization, and normal cytologic pattern recognition of this technique.

ANIMALS STUDIED

Twenty healthy, adult, cross-breed dogs.

PROCEDURES

Samples of the bulbar conjunctiva were collected after instillation of topical anesthetic drops at the ocular surface. Impression cytology was performed by applying asymmetric strips of Millipore filter on the superior temporal bulbar conjunctiva near the limbus. The filter strip was gently pressed against the conjunctiva for 5 s and removed with a peeling motion. Samples were immediately fixed in 95% ethyl alcohol, stained with periodic acid-Schiff and hematoxylin, and mounted on slides cover-slipped using synthetic resin. The slides were examined by light microscopy.

RESULTS

Microscopic examination of the impressions revealed superficial, intermediate and basal epithelial cells arranged in sheets. Keratinized epithelial cells, goblet cells and leukocytes, as well as cellular debris and mucus were observed.

CONCLUSIONS

Feasibility of impression cytology for sampling the bulbar conjunctiva of the dog and the standardization the the proposed protocol was shown. The results allowed the recognition the the normal cytologic pattern of healthy conjunctivas in dogs.

Adverse health effects in humans exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)

The environmental contaminant 2,3,7,8-tetrachlordibenzo-p-dioxin (TCDD) belongs to the category of highly toxic, persistent organic pollutants that accumulate in animal fat and plant tissues. Today, background TCDD levels in human fat are showing a decreasing trend. The food chain is the main source of exposure in the human population. TCDD regulates the expression of a wide range of drug-metabolizing enzymes and has an impact on a large number of biological systems. The most pronounced effects have occurred in occupational settings following the uncontrolled formation of TCDD after industrial accidents, as well as in rare intentional intoxications. Although the acute effects of TCDD exposure are well described in the literature, the long-term consequences have been underevaluated. The most well-known symptoms of severe acute intoxication are chloracne, porphyria, transient hepatotoxicity, and peripheral and central neurotoxicity. Because of the long-term persistence of TCDD in the human body, atherosclerosis, hypertension, diabetes, vascular ocular changes, and signs of neural system damage, including neuropsychological impairment, can be present several decades after massive exposure. Such chronic effects are nonspecific, multifactorial, and may be causally linked to TCDD only in heavily intoxicated subjects. This opinion is supported by the dose-dependent effect of TCDD found in exposed workers and by experimental animal studies.

Five-year Follow-up of Laser in situ Keratomileusis for Hyperopia Using the Technolas Keracor 117C Excimer Laser

PURPOSE

To evaluate safety, predictability, efficiency, and long-term stability of laser in situ keratomileusis (LASIK) for spherical hyperopia.

METHODS

This study was a retrospective 5-year analysis of 67 patients (125 eyes) who had LASIK for spherical hyperopia; preoperative mean manifest spherical equivalent refraction was +3.84+/-1.13 D (range +1.00 to +6.50 D) and mean astigmatism was 0.37+/-0.27 D (range 0 to 1.00 D). Preoperative spherical equivalent refraction for the low hyperopia group was +1.00 to +2.75 D; medium hyperopia group, +3.00 to +4.25 D, and high hyperopia group, +4.50 to +6.50 D. All surgeries were performed using the scanning Chiron Technolas Keracor 117C excimer laser. Uncorrected and best spectacle-corrected visual acuity, predictability, long-term stability of refraction, and complications were analyzed.

RESULTS

At 5 years after hyperopic LASIK, mean spherical equivalent refraction for the low hyperopia group was +0.48D+/-0.79 D; medium hyperopia group, +1.52+/-1.45 D; high hyperopia group C, +3.39+/-1.98 D. The percentage of eyes with a spherical equivalent refraction within +/-0.50 D of emmetropia for the low hyperopia group was 63% (37 eyes); medium hyperopia group, 42% (20 eyes); high hyperopia group, 22% (4 eyes). Eyes with chronic dry eye symptoms had a mean difference in spherical equivalent refraction from target refraction of +1.43 D compared with +0.84 D for eyes without dry eye symptoms. Five eyes (4%) lost 2 lines of BSCVA at 5 years.

CONCLUSION

LASIK was safe, effective, and stable for primary hyperopia between +1.00 and +3.00 D. Higher amounts of hyperopia had poor long-term stability, especially eyes with more than +4.25 D. Chronic dry eye symptoms were associated with regression over time.

Impression cytology of the ocular surface: a review

PURPOSE

To historically review the technique of impression cytology as a minimally invasive diagnostic tool for ocular surface pathology.

METHODS

A comprehensive review of published literature cited in PubMed since the first description of impression cytology in 1977 up to date has been undertaken.

RESULTS

A wide range of processing methods have been adapted to the technique of impression cytology (from conjunctiva, cornea or limbus): regular light microscopy with different stainings, transmission and scanning electron microscopy, immunofluorescence, immunocytochemistry, polymerase chain reaction analysis, immunoblotting analyses, or flow cytometry. At present, it is widely used as a non-invasive alternative to the full-thickness biopsy for the obtention of epithelial cells from the ocular surface.

CONCLUSIONS

Impression cytology represents a non- or minimally invasive biopsy of the ocular surface epithelium with no side effects or contraindications. It has demonstrated to be a useful diagnostic aid for a wide variety of processes involving the ocular surface. In addition, and mainly during the last decade, its use as a research tool has experienced an enormous growth and has greatly contributed to the understanding of ocular surface pathology.