The effects of long-term topical glaucoma medication on conjunctival impression cytology

Squeezability of eye drop containers used in dry eye disease management

CLINICAL RELEVANCE

Ocular lubricants are the mainstay of dry eye management and are available in a variety of formulations and bottle designs. The squeezability of ocular lubricant bottles may influence administration and compliance.

BACKGROUND

A key component for managing dry eye disease is the use of ocular lubricants. The different bottle types, each with their unique material strength and dispensing mechanism, may be challenging for patients with limited hand and pinch strength. The aim of this study was to evaluate the force required to expulse a drop from different eye drop containers used in the management of dry eye disease.

METHODS

The force, in newtons (N), required to expulse a drop from different eye drops was evaluated five times using a force gauge, and divided by bottle type, i.e. tubes, unidose, multidose with preservatives, and multidose preservative free (MDPF) bottles.

RESULTS

Sixty (n = 60) bottles were examined with 57 eye lubricants and 3 dry eye medications (cyclosporine (0.5% and 0.9%), and lifitegrast). The average force varied depending on the bottle type (tubes 4.28 ± 1.29 N; unidose 14.24 ± 4.83 N; multidose 16.62 ± 5.21 N; MDPF 26.68 ± 8.32 N, p < 0.001). Post-hoc test revealed that MDPF bottles required more force than all other bottle types (p < 0.001), and among those, the ophthalmic squeeze dispenser bottle required significantly more force (p < 0.001). Lifitegrast required more force (17.38 ± 2.13 N) than cyclosporine 0.5% (9.16 ± 0.80 N, p < 0.024) and cyclosporine 0.9% (5.68 ± 0.40 N, p < 0.001), but was not significantly different from unidose ocular lubricants (p > 0.05).

CONCLUSION

The squeezability of bottles used in dry eye disease management varies with bottle type. Hand and pinch strength should be considered when choosing products for dry eye disease management, as the squeezability of an ophthalmic drop can influence its administration and compliance.

Clinico-cytological analysis of conjunctiva and ocular surface symptoms of patients on topical anti-glaucoma medications attending Lagos University Teaching Hospital, Lagos, Nigeria: A case-control study

Background

The long-term use of topical anti-glaucoma medications is often associated with ocular surface toxicity that can affect the patient's drug compliance and quality of life. This study assessed the effect of these medications, using cytological changes of the conjunctiva and ocular surface symptoms.

Materials and Methods

This was a clinic-based, case-control study that was conducted at the Lagos University Teaching Hospital that compared glaucoma patients on topical medications with age-sex-matched controls. The controls were non-glaucoma patients, who were not on any topical ocular medications at least 6 months prior to the study. The Ocular Surface Disease Index (OSDI) questionnaire was used to assess ocular surface symptoms. Schirmer's I test, tear film break-up time (TBUT) test and corneal fluorescein staining of the ocular surface were used for ocular surface disease (OSD) assessment and conjunctival impression cytology (CIC) for histological assessment and grading.

Results

Six hundred and ninety-six eyes of 348 respondents, 174 cases and 174 controls, were assessed for OSD. The mean ages of the case and control groups were 56.3 ± 12.9 years and 55.5 ± 13.2 years, respectively, with no statistical difference (P = 0.589). All ocular parameters assessed were significantly abnormal in the case group compared to the control group. The use of topical anti-glaucoma medications was significantly associated with abnormal TBUT (P < 0.001), Schirmer's test (P < 0.001), ocular surface staining (P < 0.001), CIC (P < 0.001) and OSDI scores (P = 0.001). A significant association was seen between abnormal TBUT and the number of medications (P = 0.044, odds ratio [OR] =0.79, 95% confidence interval [CI]: 0.44-1.14), between abnormal ocular surface staining and duration of anti-glaucoma medications usage (P = 0.0104, OR = 1.2, 95% CI: 1.04-1.43) and between abnormal CIC and the duration of anti-glaucoma medications (P = 0.0007, OR = 0.7, 95% CI: 0.59-0.86).

Conclusion

The study demonstrates that prolonged use of topical anti-glaucoma medications may be associated with damage to the ocular surface structures.

Topical preservative-free ophthalmic treatments: an unmet clinical need

Introduction: The main role of preservatives in eyedrops is to ensure sterility and microbiological integrity of the drug, and to facilitate the penetration of active compounds into the eye. However, several studies documented significant toxic effects induced by preservatives, especially on the ocular surface. Consequently, most of the ophthalmic medications became progressively available in preservative-free (PF) formulations.Areas covered: We analyzed pre-clinical and clinical studies on PF eyedrops with particular attention to common chronic diseases such as dry eye and glaucoma. We discussed about the pros and cons of using PF eyedrops, in terms of efficacy, safety, and social-economic aspects.Expert opinion: There are still unresolved issues that make hard for PF medications to definitively conquer the drug market. Despite robust pre-clinical evidences of less toxicity, the low number of randomized clinical trials does not permit to state that PF eyedrops have, in clinical practice, a similar efficacy or a higher safety compared to preserved forms. These aspects limit their use to chronic diseases requiring long-term therapies with multiple daily instillations, especially in the presence of concomitant ophthalmic diseases that expose to a risk of ocular surface worsening.

Conjunctival Goblet Cells, the Overlooked Cells in Glaucoma Treatment

Glaucoma is the leading cause of irreversible blindness worldwide. Although no definitive cure exists, lowering of the intraocular pressure decreases the rate of progression in the majority of patients with glaucoma. Antiglaucomatous treatment modalities consist predominantly of chronic use of eye drops. It has become increasingly evident that long-term exposure to eye drops has a significant impact on the ocular surface, and thereby on patient compliance and quality of life. Maintenance of the ocular surface is highly dependent on a stable tear film. Conjunctival goblet cells (GCs) of the ocular surface play an important role in providing the innermost mucin layer of the tear film and are essential for maintaining the ocular surface homeostasis. Recent studies have reported severe side effects of antiglaucomatous drops on GCs. In particular, a preservative containing antiglaucomatous drops have been shown to affect the viability and functions of the GCs. Furthermore, GC density has been suggested as a potential predictor of surgical outcome after filtration surgery. The present review provides an overview of the current literature on the impact of antiglaucomatous eye drops on GCs as well as the impact on the ocular surface. Moreover, the existing evidence of a possible association between GC density and glaucoma filtration surgery outcome is summarized. We conclude that prostaglandin analogs spare the conjunctival GCs more compared with other antiglaucomatous drops and that GCs may be a good predictor of surgical outcome after filtration surgery. Overall, given the multiple functions of GCs in the ocular surface homeostasis, dedicated strategies should be adopted to preserve this cell population during the course of glaucoma.

ICON: Diagnosis and management of allergic conjunctivitis

Ocular allergy (OA), interchangeably known as allergic conjunctivitis, is a common immunological hypersensitivity disorder affecting up to 40% of the population. Ocular allergy has been increasing in frequency, with symptoms of itching, redness, and swelling that significantly impacts an individual's quality of life (QOL). Ocular allergy is an often underdiagnosed and undertreated health problem, because only 10% of patients with OA symptoms seek medical attention, whereas most patients manage with over-the-counter medications and complementary nonpharmacological remedies. The clinical course, duration, severity, and co-morbidities are varied and depend, in part, on the specific ocular tissues that are affected and on immunologic mechanism(s) involved, both local and systemic. It is frequently associated with allergic rhinitis (commonly recognized as allergic rhino conjunctivitis), and with other allergic comorbidities. The predominance of self-management increases the risk of suboptimal therapy that leads to recurrent exacerbations and the potential for development of more chronic conditions that can lead to corneal complications and interference with the visual axis. Multiple, often co-existing causes are seen, and a broad differential diagnosis for OA, increasing the difficulty of arriving at the correct diagnosis(es). Ocular allergy commonly overlaps with other anterior ocular disease disorders, including infectious disorders and dry eye syndromes. Therefore, successful management includes overcoming the challenges of underdiagnosis and even misdiagnosis by a better understanding of the subtleties of an in-depth patient history, ophthalmologic examination techniques, and diagnostic procedures, which are of paramount importance in making an accurate diagnosis of OA. Appropriate cross-referral between specialists (allergists and eyecare specialists) would maximize patient care and outcomes. This would significantly improve OA management and overcome the unmet needs in global health.

Tear Film Osmolarity, Ocular Surface Disease and Glaucoma: A Review

Glaucoma is the second leading cause of blindness in the world, affecting more than 60 million people globally. In order to reduce the progression of the disease, both medical and surgical treatments are used. Frequent side effects of both treatments include a range of modifications of the ocular surface grouped as the Ocular Surface Disease (OSD), which include Dry Eye Disease (DED). DED and other OSD negatively impact on the success of anti-glaucoma treatments and reduce the adherence to medical therapies. Tear film osmolarity (TFO) is a relatively novel test which has become a hallmark of DED. The aim of this paper was to review the association between OSD, DED and glaucoma in view of published TFO data, and to discuss future fields of research and treatments on the topic of glaucoma iatrogenic damage.

Evaluation of Ocular Surface Disease in Asian Patients with Primary Angle Closure

Objective:

To evaluate the incidence of ocular surface disease (OSD) and to determine the effects of topical pressure-lowering drugs on ocular surface disease in primary angle closure patients.

Methods:

This was a cross-sectional comparative study comparing primary angle closure glaucoma (PACG) patients (Group A) with primary angle closure and primary angle closure suspect (Group B). Group A was treated with topical pressure-lowering drugs; Group B was not. Data on ocular diagnosis and details of treatment were obtained from medical records. Ocular surface disease incidence was assessed using the Ocular Surface Disease Index (OSDI) questionnaire and from clinical signs using Schirmer’s test, tear break-up time and corneal fluorescein stain. Predictive Analytic Software 20 and STATA analysis software were used for statistical analyses.

Results:

Group A demonstrated a higher rate of OSD (OSDI 52.3%, Schirmer’s test 70.5%, tear break-up time (TBUT) 75%, corneal staining 77.3%) compared to Group B (OSDI 39.0%, Schirmer’s test 73.2%, TBUT 58.5% and cornea staining 14.6%) except for Schirmer’s test. There was a significant difference in mean score of OSDI (p=0.004), TBUT (p=0.008) and cornea staining (p<0.001) between two groups. Primary angle closure glaucoma treated with more than two medications and for more than three years had worse ocular surface disease parameters but without statistical significant difference.

Conclusion:

Ocular surface disease is common in PACG patients treated with topical pressure-lowering drugs. Topical pressure-lowering drugs caused significant OSD symptoms and signs except for tear production in PACG patients. Thorough evaluation of ocular surface disease is important to ensure appropriate treatment and intervention in PACG patients.

Symptoms and signs of ocular surface disease related to topical medication in patients with glaucoma

Purpose

The aim of this study was to assess signs and symptoms of ocular surface disease (OSD) and the cytomorphological changes of ocular surface in glaucoma patients using preserved antiglaucoma drops.

Methods

In this cross-sectional study, 109 participants (79 patients with topical medication and 30 untreated controls) completed the Ocular Surface Diseases Index (OSDI) questionnaire and underwent an ophthalmic examination, including Schirmer test, tear film breakup time (TBUT), and fluorescein staining. Conjunctival specimens were collected by impression cytology and analyzed by light microscopy using Nelson’s grading scheme (grades 0–3). This classification is based on the nucleus-to-cytoplasm ratios of epithelial cells and the numbers of goblet cells, with grade 2 considered abnormal.

Results

The medication group had significantly shorter TBUT (median [interquartile range]: 6.0 seconds [5.0–8.0 seconds] vs 9.5 seconds [6.0–12.3 seconds]; P<0.03), greater fluorescein staining (1.0 [0.75–1.25] vs 0 [0–0.25]; P<0.001), and higher impression cytology grade than the control group (median [range]: 1.0 [1:2 to 1:6] vs 0.6 [1:2 to 1:4]; P<0.001). The increasing number of drops instilled per day was associated with an increase in fluorescein staining (Spearman’s rho r=0.475; P<0.001) and shorter TBUT (r=−0.278; P=0.014). The OSDI did not discriminate between the two groups.

Conclusion

Clinical tests and impression cytology showed ocular surface damage in patients using preserved antiglaucoma medications. However, there was no statistically and clinically significant difference in symptoms measured by OSDI score between the medication and control groups.

Does the use of preoperative antiglaucoma medications influence trabeculectomy success?

PURPOSE

To investigate the influence of preoperative antiglaucoma medications on trabeculectomy outcome.

METHODS

Two hundred fifteen eyes, which underwent primary trabeculectomy, were retrospectively analyzed. The average follow-up was 39.8±30.3 months. The only cases of primary open-angle glaucoma, with or without pseudoexfoliation (PXF), were included. "Complete success" was defined as intraocular pressure (IOP) <18 mmHg without glaucoma medications, whereas relative success was defined as the same IOP target with medications. The influence of the preoperatively used glaucoma medications on surgical success was analyzed by univariate Pearson correlation and multivariate (ordinal) regression analysis.

RESULTS

There were 118 male (54.9%) and 97 female (45.1%) patients with a mean age of 66.9±9.3 years. PXF glaucoma (PXFG) was present in 93 eyes (43.3%). In 33 patients (15.3%), diabetes mellitus (DM) was present. Complete success was achieved in 116 eyes (54%), relative success in 81 eyes (37.6%), and failure in 18 eyes (8.4%). Neither the total number nor the duration of glaucoma medications used before trabeculectomy was found to have any statistically significant influence on surgical success. In statistical analysis, a combination of topical beta-blocker and carbonic anhydrase inhibitor (BB+CAI) used before surgery was found to be associated with statistically better outcome, whereas the preoperative use of topical beta-blockers alone could have a negative influence on success. PXF was shown to be independently associated with trabeculectomy outcome on multivariate regression analysis.

CONCLUSION

The glaucoma medications used preoperatively were not found to have any statistically significant negative influence on the trabeculectomy outcome and use of the combined BB+CAI preparation could have a positive influence, whereas the use of topical beta-blockers alone could have a negative influence on success, although not statistically significant. The presence of PXF was independently associated with a better surgical outcome.

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.

Toxic-inflammatory effects of prostoglandin analogs on the ocular surface

PURPOSE

To investigate the toxic-inflammatory effects of prostaglandin analogs on the ocular surface.

MATERIALS AND METHODS

Twenty-three rats were divided into four groups. Bimatoprost 0.03% (I), latanoprost 0.005% (II), and travoprost 0.004% (III) were applied during 6 months; a control group (IV) received no treatment. Dysplasia and keratinization were evaluated on the ocular surface. In the subepithelial area, the number of lymphocytes and mast cells were counted morphologically, and collagen staining densities were compared subjectively in groups.

RESULTS

The ratio of keratinization was 3/12 and 1/10, in groups I and II. The lymphocyte cell counts were 1.4 ± 0.19, 2.2 ± 0.39, 2.27 ± 0.33, and 1.87 ± 0.35 (p > .05). The mast cell counts were 2.58 ± 0.5, 5.4 ± 1.1, 5.7 ± 0.58, and 3.0 ± 0.59. They were significantly higher in groups II and III than in group I (p < .05). Mean collagen density scores were 1.00 ± 0.85, 2.00 ± 0.00, and 1,73 ± 0.70. Group II and III scores were higher than group I scores (p < .05).

CONCLUSION

Latanoprost and travoprost seem to have more toxic-inflammatory effects on the ocular surface than bimatoprost.

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.

Corneal epithelial cell viability following exposure to ophthalmic solutions containing preservatives and/or antihypertensive agents

INTRODUCTION

This in-vitro study compared the toxicity of bimatoprost 0.01% containing benzalkonium chloride (BAK) 0.02% with other commercial BAK-free or BAK-containing prostaglandin analogs.

METHODS

Six test solutions were evaluated: travoprost 0.004% with polyquaternium-1 0.001% (PQ), PQ, bimatoprost 0.01% with BAK 0.02%, latanoprost 0.005% with BAK 0.02%, tafluprost 0.0015% preservative free (PF), and BAK 0.02%. Phosphate-buffered saline (PBS) was the live control and 70% methanol was the dead control. Confluent human corneal epithelial cells were incubated with test solutions (diluted 1:5 or 1:10 with PBS) or control solutions for 10 or 25 min, after which cells were fluorescently labeled to distinguish live and dead cells. Data were expressed as a percentage of PBS live-cell fluorescence for automated readouts. Live and dead cells were manually counted for numeric analyses.

RESULTS

For 1:5 and 1:10 dilutions using automated readout, cells exposed to bimatoprost with BAK, latanoprost with BAK, and BAK alone demonstrated significant reductions in the live cell signal compared with PBS, travoprost with PQ, and PQ alone (all P < 0.001). They also demonstrated significantly greater toxicity than tafluprost PF for 1:5 dilutions (all P < 0.001) and 1:10 dilutions (P ≤ 0.02), except for 1:10-diluted bimatoprost with BAK (P = 0.41). For 1:5 dilutions using manual cell count, cells exposed to bimatoprost with BAK demonstrated significant reductions in the percentage of live cells compared with PBS (P = 0.02). For 1:10 dilutions using manual cell count, cells exposed to bimatoprost with BAK, latanoprost with BAK, and BAK alone demonstrated significantly greater toxicity than PBS, travoprost with PQ, PQ alone, and tafluprost PF (all P ≤ 0.03). No significant differences were observed among PBS, travoprost with PQ, and PQ alone under any test conditions (P ≤ 0.63).

CONCLUSION

This study demonstrated that BAKcontaining solutions, including bimatoprost 0.01% with BAK, were toxic to human corneal epithelial cells, whereas BAK-free solutions showed little to no evidence of toxicity.

The effect of additional topical cyclosporine or vitamin A on the ocular surface during antiglaucoma medication administration

PURPOSE

To investigate the effects of topical application of cyclosporine or vitamin A on the ocular surface during the concurrent administration of antiglaucoma drugs.

METHODS

Thirty rabbits were randomized into 5 groups. Group 1 was administered timolol, group 2 received travoprost, group 3 received a travoprost/timolol fixed combination solution, group 4 received timolol and travoprost, and group 5 received timolol, travoprost, and dorzolamide. Each group was divided into a subgroup that received only the antiglaucoma medication (subgroup A), a subgroup that received topical cyclosporine in addition to the antiglaucoma medication (subgroup B), and a subgroup that received topical vitamin A in addition to the antiglaucoma medication (subgroup C). Conjunctival impression cytology specimens were collected at baseline and at weeks 1, 3, and 6. Conjunctival biopsy specimens were collected at week 6.

RESULTS

The impression cytologic study results are as follows: statistically significant differences were found between groups 4A and 4B and between groups 4A and 4C at week 6 (p = 0.004, p = 0.006, respectively) and between groups 5A and 5B and between groups 5A and 5C at weeks 3 and 6 (p = 0.006, p = 0.008 at week 3, p = 0.003, p = 0.004 at week 6, respectively). No statistically significant differences were found between subgroup B and subgroup C in any of the groups at any of the times evaluated (p > 0.05). The conjunctival biopsy specimens from groups 1, 2, and 3 showed no distortion, but groups 4A and 5A showed distortion of the conjunctival epithelial structures. Groups 4B, 4C, 5B, and 5C showed less distortion of the conjunctival epithelial structures.

CONCLUSION

Administration of cyclosporine or vitamin A may reduce the adverse ocular surface changes caused by long-term administration of antiglaucoma drugs.

Preservative use in topical glaucoma medications

Benzalkonium chloride (BAK) is the principal preservative employed in topical ocular hypotensive medications, although alternative compounds recently have begun to be employed or examined. Individual clinical trials have shown that exposure to BAK concentrations contained in ophthalmic solutions does not produce adverse sequelae in the majority of glaucoma patients, but concerns continue with regard to its long-term use. These concerns have resulted from an extensive research effort, including preclinical studies with in vitro and in vivo models, as well as recent clinical investigations dedicated specifically to this issue. The aim of this systematic literature review of both preclinical and clinical data was to determine the relevance of these findings to clinical practice. Most preclinical studies reported negative effects of BAK exposure, but with few exceptions, BAK concentrations and exposure times greatly exceeded those likely to be experienced by patients, given the normal physiological dilution by the tear film. In addition, consistent evidence of BAK-related toxicity did not emerge from our review of dedicated clinical investigations. Thus, taken together, current evidence supports the safety of BAK for most glaucoma patients, although subpopulations with abnormal tearing may benefit from alternative preservative compounds or preservative-free formulations. Further studies to identify these populations are needed.

Effects of antiglaucoma drugs on the ocular surface in rabbits: a fixed-combination drug versus two concomitant drugs

PURPOSE

We investigated the effects of a fixed-combination antiglaucoma drug and compared it with two concomitant antiglaucoma drugs on the ocular surface.

METHODS

Twenty-four rabbits were randomized into four groups. Group 1 was administered timolol, group 2 travoprost, group 3 a travoprost/timolol fixed-combination solution, and group 4 timolol and travoprost. Conjunctival impression cytology specimens were collected at baseline and weeks 1, 3, and 6, and conjunctival biopsy specimens at week 6.

RESULTS

The impression cytology study results were as follows: No statistically significant differences among group 1-3 at any time (p > 0.05); a statistically significant difference between groups 3 and 4 at week 6 (p = 0.003); a statistically significant difference between baseline and group 4 at week 6 (p = 0.008). Conjunctival biopsy specimens of group 1-3 showed no distortion of the conjunctival epithelial structures, but group 4 showed decreased layers of epithelial cells with fewer periodic acid-Schiff (PAS) (+) goblet cells.

CONCLUSIONS

A fixed-combination antiglaucoma drug is beneficial in reducing adverse ocular surface changes in long-term use. This is believed to be due to the smaller concentration of preservatives contained in the fixed-combination drug.

Ocular preservatives: associated risks and newer options

Presence of a preservative in an ocular medication has often been considered a culprit in damaging the epithelium. However, the inclusion of a preservative is equally necessary, especially in multiple-dose containers, in order to protect against dangerous organisms accidentally gaining access during instillation. Benzalkonium chloride (BAK), chlorobutanol, chlorhexidine acetate (CHA), and phenylmercuric nitrate or acetate are some commonly used preservatives in eye preparations. New preservatives with a wide range of activity and good safety profiles have been introduced in the market, such as stabilized oxychloro complex (SOC), sofZia, and sodium perborate. In the present review, we discuss various conventional and newly proposed and patented preservative molecules for ocular use. Reasons for discontinuing traditional preservatives and the need for less-toxic molecules are discussed at length, along with newer options coming up in this area.

An in vivo confocal microscopy and impression cytology analysis of preserved and unpreserved levobunolol-induced conjunctival changes

PURPOSE

To provide an in vivo confocal microscopy (IVCM) and impression cytology analysis of preserved-and unpreserved levobunolol-induced changes of conjunctival epithelium.

METHODS

27 eyes of 27 patients were consecutively randomized to receive preserved or unpreserved levobunolol; all patients had a recent diagnosis of primary open angle glaucoma (POAG) or ocular hypertension and were not previously treated with topical medications. IVCM and impression cytology were performed before and after six months of therapy. Goblet cells density and a conjunctival epithelium regularity index were considered in the IVCM analysis, whereas impression cytology specimens were graded and scored in accordance with Nelson's method.

RESULTS

After six months of therapy, IVCM and impression cytology parameters showed significant differences with respect to baseline in both groups (p<0.001); significant differences were also found between the two groups (p<0.001). The IVCM analysis showed a goblet cells density reduction (61% and 17% from baseline, respectively in group 1 and 2) (p<0.001) and an higher index of epithelial regularity (p<0.001) in both groups; the impression cytology analysis showed an higher score in both groups (p<0.001).

CONCLUSIONS

All the IVCM and impression cytology parameters correlated well with the conjunctival modifications induced by the topical therapy, suggesting the less toxicity of unpreserved drugs.

Effects of topical antiglaucoma medications on the ocular surface

The side effects of topical antiglaucoma medications and their preservatives range from ocular discomfort to sight-threatening alterations of the ocular surface. Conjunctival hyperemia, decreased tear production and function, and superficial punctate keratitis are among the most common signs seen on routine clinical examination. Squamous cell metaplasia and changes in cell morphology have been demonstrated by impression cytology studies and evaluation of biopsy specimens, and inflammatory effects are documented by the presence of inflammatory markers. The adverse effects of topical antiglaucoma eyedrops interfere with the treatment of glaucoma on two levels: first, the discomfort produced by the eye drops discourages patient compliance; and, second, long-term treatment with eyedrops is associated with a higher failure of filtration surgery. The detailed mechanism of inflammatory response and/or direct toxicity of eye drops has yet to be determined, but it may vary with the different classes of eye drops, different preservatives, and durations of treatments. Upcoming multicenter trials for new antiglaucoma eye drops should specifically evaluate ocular surface effects.

Effects of topical antiglaucoma application on conjunctival impression cytology specimens

PURPOSE

To evaluate the changes in conjunctival impression cytology specimens from patients receiving various topical antiglaucoma medications.

DESIGN

Cross-sectional comparative study.

METHODS

Impression cytology specimens were obtained from the eyes taking no topical medication (n = 20) and from the eyes taking various antiglaucoma medications (timolol n = 34; latanoprost n = 40; dorzolamide n = 32; timolol + latanoprost n = 30; timolol + dorzolamide n = 34). Specimens were graded on a scale of zero to three according to Nelson's method.

RESULTS

Cytology scores were significantly higher in the medication group than the control group. Mean cytology scores of the control, timolol, latanoprost, dorzolamide, timolol + latanoprost, and timolol + dorzolamide group were 0.20, 1.62, 2.00, 1.75, 2.13, and 2.44, respectively. Among the medication groups, cytology scores were significantly lower in the monotherapy group than the fixed-combination therapy group.

CONCLUSIONS

Various topical antiglaucoma medications induce a significant degree of squamous metaplasia. Conjunctival surface could be altered after the long-term use of antiglaucoma medication.

Impression cytology of the ocular surface

Impression cytology refers to the application of a cellulose acetate filter to the ocular surface to remove the superficial layers of the ocular surface epithelium. These cells can then be subjected to histological, immunohistological, or molecular analysis. Proper technique is essential as the number of cells sampled can vary considerably. Generally two to three layers of cells are removed in one application but deeper cells can be accessed by repeat application over the same site. Applications for impression cytology include diagnosing a wide range of ocular surface disorders, documenting sequential changes in the conjunctival and corneal surface over time, staging conjunctival squamous metaplasia, and monitoring effects of treatment. It is also a useful investigational tool for analysing ocular surface disease with immunostaining and DNA analysis. It is non-invasive, relatively easy to perform, and yields reliable information about the area sampled with minimal discomfort to the patient. Major ophthalmic centres should develop and introduce this technique into routine clinical practice. This is best achieved with a team approach including the ophthalmologist, pathologist, microbiologist, and the immunologist.

Allergic reaction to topical eyedrops

PURPOSE OF REVIEW

To examine recently published papers dealing with drug-induced allergic reactions. As allergy is only one possible mechanism, this review was extended to all reports or studies describing allergic, inflammatory or toxic effects related to eyedrops since 2004.

RECENT FINDINGS

These studies were first classified into clinical reports or surveys, experimental works and biological studies showing drug-induced effects on the ocular surface or eyelids. Studies aimed at determining the role of preservatives or comparing preservative-free and preserved eyedrops were further analysed separately.

SUMMARY

Reports on allergic or toxic reactions of eyedrops are published repeatedly. The reports raising the most important issues are those concerning antiglaucoma drugs. They consistently describe inflammatory reactions at the conjunctival level, with strong evidence that preservative is a major source of toxicity for the ocular surface.

Conjunctival epithelial cell expression of interleukins and inflammatory markers in glaucoma patients treated over the long term

PURPOSE

To compare the conjunctival epithelial cell expressions of inflammatory cytokines in normal subjects and in glaucoma patients treated over the long term.

DESIGN

Case-control study.

PARTICIPANTS

A total of 69 glaucoma patients treated over the long term and 15 normal subjects with no ocular abnormality or topical treatment.

METHODS

Amongst the 69 glaucoma patients, 27 were treated with preserved beta-blockers, 24 with unpreserved 0.5% timolol, and the other 18 patients with an association of > or =2 preserved drugs. All patients were treated for more than 1 year with the same treatment, with no significant differences between groups for mean ages and durations of treatment at the time of the study. Impression cytology specimens were taken and processed for immunofluorescence techniques. Conjunctival cell expressions of HLA DR, as a standard for inflammatory level, and the interleukins IL-6, IL-8, and IL-10 were obtained and quantified using flow cytometry.

MAIN OUTCOME MEASURES

Immune markers and proinflammatory cytokines in impression cytology specimens.

RESULTS

We found a significantly increased expression of all immunoinflammatory markers and mediators in the conjunctival epithelium of glaucoma patients compared with normal eyes. Human leukocyte antigen DR was significantly higher in the 2 groups receiving preserved drugs than in the unpreserved timolol group. The 3 interleukins were similarly overexpressed in all glaucoma groups, with no significant between-groups differences except for the expression level of IL-8, which was significantly higher in the multitreatment group than in the preservative-free one.

CONCLUSIONS

The present study confirms the increased expression of immunoinflammatory markers by the conjunctival epithelium of glaucoma patients treated over the long term. The development of nontoxic preservatives or preservative-free solutions is therefore of great interest.

Corneal and Conjunctival Changes Caused by Commonly Used Glaucoma Medications

PURPOSE

To evaluate the extent of epithelial corneal and conjunctival changes associated with prolonged use of topical glaucoma medications.

METHODS

Thirty eyes of 15 New Zealand white rabbits were randomized to 1 of 6 treatment groups: artificial tears (Refresh Tears, carboxymethyl cellulose 0.5%) BID, brimonidine Purite 0.15% BID, bimatoprost 0.03% QD, dorzolamide 2% BID, timolol maleate 0.5% BID, or latanoprost 0.005% QD for 30 days. Corneal damage was evaluated by scanning electron microscopy and graded on a standard scale by a masked observer. Conjunctival inflammation was evaluated with light microscopy, and inflammatory cells were counted in the epithelium and superficial and deep stroma by a masked observer according to a standard protocol.

RESULTS

In the cornea, artificial tears produced significantly less damage than dorzolamide or latanoprost (P = 0.001), and brimonidine Purite produced significantly less damage than dorzolamide, timolol, or latanoprost (P = 0.001). The mean damage scores with bimatoprost were significantly lower than with dorzolamide, timolol, or latanoprost (P = 0.002). In the conjunctiva, the number of inflammatory cells in the epithelium was significantly lower in eyes treated with artificial tears or brimonidine Purite than in eyes treated with timolol or latanoprost (P = 0.042).

CONCLUSIONS

Although the adverse effects of glaucoma medications on the ocular surface are likely multifactorial, 1-month treatment with glaucoma medications containing higher levels of benzalkonium chloride (BAK) resulted in greater corneal damage and conjunctival cell infiltration than medications preserved with Purite or with lower levels of BAK. Using glaucoma medications with alternative preservatives or low levels of BAK may help preserve ocular health.

Effects of common ophthalmic preservatives on ocular health

Preservatives are an important component of ophthalmic preparations, providing antimicrobial activity in the bottle and preventing decomposition of active drug. Often underrecognized, however, are the significant cytotoxic effects of preservatives associated with long-term therapy and especially use of multiple preserved drugs. The most common preservatives in ophthalmic preparations for glaucoma and surface eye disease-benzalkonium chloride (BAK), chlorobutanol, sodium perborate, and stabilized oxychloro complex (SOC)-were reviewed. Compared with other preservatives, SOC caused the least amount of damage to rabbit corneal epithelial cells. BAK has demonstrated cytotoxic effects in cell culture, as well as in animal and human studies. Physicians should consider treatment with new-generation preparations containing low-risk preservatives such as SOC, especially in patients receiving multiple ophthalmic medications.

Dry eye: an update on clinical diagnosis, management and promising new treatments

Dry eye conditions are prevalent with one in four to five patients presenting to eye care practitioners having dry eye signs and/or symptoms. An intimate relationship exists between the ocular surface and the tear film. The cycle of tear film instability and ocular surface damage characteristic of dry eye conditions suggests that dry eye represents a dysfunction of an integrated ocular surface-lacrimal gland unit. Therefore, dry eye is a multifactorial condition and an approach based on clinical subtypes is required for diagnosis and management. There is increasing evidence that inflammation is a contributing and exacerbating factor in dry eye conditions and anti-inflammatory or immunomodulatory therapy for chronic dry eye conditions may facilitate ocular surface healing. Other promising new treatments for dry eye include new generation artificial tear polymers and preservative systems, secretagogues, topical androgen supplements and surgical techniques for ocular surface reconstruction.