Ocular surface changes induced by topical application of latanoprost and timolol: a short-term study in glaucomatous patients with and without allergic conjunctivitis

Ocular Tolerability of Bimatoprost 0.1 mg/mL Preservative-Free versus Bimatoprost 0.1 mg/mL with Benzalkonium Chloride or Bimatoprost 0.3 mg/mL Preservative-Free in Patients with Primary Open-Angle Glaucoma

This study aimed to evaluate whether the therapeutic switch from a formulation of Bimatoprost 0.1 mg/mL with benzalkonium chloride (BAK) or Bimatoprost 0.3 mg/mL preservative-free to a formulation of Bimatoprost 0.1 mg/mL preservative-free could improve eye surface conditions in patients with glaucoma; intraocular pressure (IOP) was also evaluated. All patients meeting the inclusion criteria were eligible for the therapeutic switch to Bimatoprost 0.1 mg/mL preservative-free. At each check visit, enrolled patients underwent a break-up time (BUT) test, an ocular surface disease index (OSDI) test, and a three-point tonometric curve. A total of 40 patients were enrolled (23 were in therapy with Bimatoprost 0.1 mg/mL with BAK and 17 with Bimatoprost 0.3 mg/mL preservative-free). Significant differences of OSDI and BUT between Bimatoprost 0.1 mg/mL with BAK at baseline vs. Bimatoprost 0.1 mg/mL preservative-free at 14 and 28 days (p < 0.0001 and p = 0.0003, respectively) were recorded. Similarly, significant differences of OSDI and BUT between Bimatoprost 0.3 mg/mL preservative-free at baseline vs. Bimatoprost 0.1 mg/mL preservative-free at 14 and 28 days (p < 0.0001 for both) were found. Bimatoprost 0.1 mg/mL preservative-free has a better tolerability profile associated with non-therapeutical inferiority in the control of IOP compared to the other Bimatoprost formulations.

Ocular benzalkonium chloride exposure: problems and solutions

Preservatives in multidose formulations of topical ophthalmic medications are crucial for maintaining sterility but can be toxic to the ocular surface. Benzalkonium chloride (BAK)-used in approximately 70% of ophthalmic formulations-is well known to cause cytotoxic damage to conjunctival and corneal epithelial cells, resulting in signs and symptoms of ocular surface disease (OSD) including ocular surface staining, increased tear break-up time, and higher OSD symptom scores. These adverse effects are more problematic with chronic exposure, as in lifetime therapy for glaucoma, but can also manifest after exposure as brief as seven days. Multiple strategies are available to minimize or eliminate BAK exposure, among them alternative preservatives, preservative-free formulations including sustained release drug delivery platforms, and non-pharmacological therapies for common eye diseases and conditions. In this paper, we review the cytotoxic and clinical effects of BAK on the ocular surface and discuss existing and emerging options for ocular disease management that can minimize or eliminate BAK exposure.

Diagnostic tests based on pattern formation in drying body fluids - A mapping review

There are numerous diagnostic tests based on pattern formation in desiccating body fluids, where the pattern or some of its characteristics constitute the diagnostic test outcome. However, partially due to the development in different time periods, and partially due to publications in languages different from English, most of these diagnostic tests exist as separate approaches and have never been grouped, systematized, nor compared with each other. In the present mapping review, we performed a wide literature search with the aim to collect all diagnostic tests based on pattern formation in desiccating body fluids. Furthermore, we grouped the identified diagnostic tests according to their experimental protocols, type of body fluids investigated, and target conditions, and propose so for the first time a classification of different diagnostic tests based on pattern formation in desiccating body fluids. The literature search revealed 1603 publications, out of which 141 were included into the review. Following three main classification criteria (way of deposition of the fluid for desiccation, addition of reagents, and spatial restrictions during evaporation), we identified six different methods; following a further classification concerning the analyzed body fluid we identified 30 different diagnostic tests based on pattern formation in evaporating body fluids. Amongst these tests are well-known procedures such as ferning tests (tear ferning for the assessment of tear film quality, saliva and cervical mucus ferning for the detection of the fertile period, and amniotic fluid ferning for the diagnosis of fetal membrane rupture), whereas other tests are less well-established. In the latter group, the most frequently investigated body fluids were serum, saliva, and blood; the most frequently addressed target conditions were cancer, inflammation, and benign tumors. We recommend conducting further systematic reviews and meta-analyses concerning groups of methods addressing the same target condition.

[Continuous anti-glaucoma drug therapy as a risk factor of dry eye]

A preservative is a mandatory component of the eye drops designed to prevent microbial contamination in an opened bottle. Most of the preservative agents are either detergents, or oxidants; the most widely used and well-studied preservative - benzalkonium chloride - is a detergent. Due to regular usage of glaucoma eye drops, cytotoxic impact of the preservatives on anterior eye surface is considered the principal cause of its pathology, which leads to a decrease in quality of life. The high cost of preservative-free pharmacological forms and the complicated process of developing new preservatives make the usage of eye drops with minimal required concentration of preservative agent and a moistening component a good compromise. The most commonly utilized moistening component is polyvinyl alcohol - synthetic polymeric hydrogel, which is also used in artificial tears and bioengineering.

Dry Eye Syndrome-Related Quality of Life in Glaucoma Patients

Purpose

To verify the presence of dry eye syndrome (DES) in treated patients with glaucoma and to analyze DES's impact on the patients' quality of life (QOL) versus the control group.

Methods

In this observational cross-sectional study, 61 patients were enrolled at a clinical practice. Patients were divided into three groups by number of glaucoma drops instilled per day (G1=1 drop/day, G2=2 drops/day, G3=3 drops/day). A control group of 20 subjects was also selected (G0). All subjects were submitted to a complete ocular examination (including tear function and ocular surface status) and completed the 25-item National Eye Institute Visual Function Questionnaire (NEI-VFQ), Glaucoma Symptom Scale (GSS) questionnaire, and Ocular Surface Disease Index (OSDI). DES was defined as presence of punctate keratitis and decreased break-up time. Statistical analysis was performed applying the Kruskal-Wallis analysis of variance and Mann-Whitney U tests (to compare median values between groups) as well as the χ2 and Fisher test (to verify significant differences).

Results

A total of 40% of G3 and 39% of G2 patients presented DES versus 11% of G1 and 5% of G0 (p=0.01). QOL was significantly influenced and altered (NEI-VFQ 25 total mean and GSS total mean and symptoms average: p=0.0085, p=0.006, and p=0.03, respectively). OSDI pointed out differences by group: 26% of G2 and 15% of G3 presented moderate OSDI and 15% of G3 and 8.7% of G2 severe OSDI (p>0.05).

Conclusions

Patients with topically treated glaucoma present DES more often than a similar control group (p=0.01). The presence of DES negatively influences the patient's QOL. The patients with glaucoma's ocular surface status should be evaluated regularly to ensure the timely detection and treatment of pathologic signs on the ocular surface.

Combination Products for Glaucoma: An Overview of Treatment Principles

Glaucoma is a leading cause of blindness and visual impairment. Treatments that lower intraocular pressure (IOP) tend to delay progression of the condition. However, the target IOP cannot be achieved with monotherapy in many patients. If monotherapy adequately controls IOP and is well tolerated, it should not be changed, but if the therapy is only partially effective, a combination may be used. Combination therapy is eventually needed in many cases of glaucoma. Combinations may be given as adjunctive or preferably as fixed therapies. The mechanism of action and contraindications of the constituent agents should be taken into account when prescribing combinations, for optimal safety and efficacy. As treatment choice expands, prescribing patterns are changing worldwide. Fixed combination therapies are increasingly prescribed in Europe in particular for the treatment of glaucoma. They should be administered according to the current evidence-based guidelines.

The tear ferning test: a simple clinical technique to evaluate the ocular tear film

A healthy tear film is very important for many major functions of the ocular surface. Dry eye disease is a significant clinical problem that needs to be solved but the poor correlation between clinical signs and reported symptoms makes it difficult for the clinician to apply a scientific basis to his clinical management. The problem is compounded by the difficulties of evaluating the tear film due to its transparency, small volume and complex composition. Practical insight into tear film composition would be very useful to the clinician for patient diagnosis and treatment but detailed analysis is restricted to expensive, laboratory-based systems. There is a pressing need for a simple test. The tear ferning test is a laboratory test but it has the potential to be applied in the clinic setting to investigate the tear film in a simple way. Drying a small sample of tear fluid onto a clean, glass microscope slide produces a characteristic crystallisation pattern, described as a 'tear fern'. This test is currently not widely used because of some limitations that need to be overcome but several studies have demonstrated its potential. Such limitations need to be resolved so that tear ferning could be used in the clinic setting to assess the tear film.

Scanning electron microscopy applied to impression cytology for conjunctival damage from glaucoma therapy

PURPOSE

To apply scanning electron microscopy to impression cytology (IC) to evaluate conjunctival damage in patients undergoing topical glaucoma therapy.

METHODS

All patients undergoing glaucoma therapy and without ocular surface disorders between September 2012 and January 2013 were enrolled. An age- and gender-matched group without glaucoma served as the control group. Conjunctival epithelium was evaluated with the ferning test (FT), impression cytology with light optic microscopy (ICOM), and impression cytology with scanning electron microscopy (ICSEM).

RESULTS

Twenty patients (40 eyes; 11 men and 9 women, mean age 59.9 ± 11 years) constituted the treated group. The mean duration of glaucoma therapy was 25.5 ± 13.8 months (range, 6-48 months). The mean FT, ICOM, and ICSEM grades were 2.52 ± 0.5, 2.52 ± 0.6, and 2.55 ± 0.7, respectively. Treatment duration was not significantly correlated with FT/IC grade (P = 0.1), whereas it was significantly correlated with microvilli count at ICSEM (P = 0.01). The mean FT, ICOM, and ICSEM grades were significantly lower in the control group (40 eyes; 11 men and 9 women, mean age 61.1 ± 7.12 years) than in the treated group (1.22 ± 0.4, 1.25 ± 0.4 and 1.15 ± 0.3, respectively, P < 0.001).

CONCLUSIONS

The FT, ICOM, and ICSEM grades were lower in eyes undergoing glaucoma therapy than in control eyes. Treatment duration was significantly associated with a reduced microvilli count at ICSEM, but not with FT or ICOM grades. Reduction of microvilli could be the first sign of cellular damage during chronic glaucoma therapy.

Conjunctival goblet cells density and preservative-free tafluprost therapy for glaucoma: an in vivo confocal microscopy and impression cytology study

PURPOSE

To evaluate the density of conjunctival goblet cells (GCs) in glaucomatous patients treated with preservative-free (PF) tafluprost, using laser scanning confocal microscopy (LSCM) and impression cytology (IC).

METHODS

Thirty glaucomatous patients (30 eyes) naive for therapy and thirty healthy subjects (30 eyes) were enrolled. Conjunctiva was examined by means of Heidelberg Retina Tomography/Rostock cornea module. Afterwards, the specimens for IC were obtained. Patients were randomized to PF-tafluprost (Group 1) or preserved latanoprost (Group 2) and controls to the vehicle of latanoprost (Group 3) or physiological buffered saline solution (Group 4). Both LSCM and IC were performed at baseline, and after the 1st and 6th months of therapy, GC density (GCD) (cells/mm(2) ) was the main outcome measurement.

RESULTS

  Baseline. Mean GCD was 240.69 ± 25.43 and 232.65 ± 23.52, for LSCM, and 162.10 ± 23.44 and 164.71 ± 21.03 for IC in Group 1 and 2, respectively. GC density values were not significantly different in Group 3 and 4 (p > 0.05%). Month one. Mean GCD increased to 284.16 ± 43.88 and 230.62 ± 48.32 in Group 1 (p < 0.001) and to 297.86 ± 26.87 and 221.78 ± 43.02 in Group 2 (p < 0.05), measured with LSCM and IC, respectively. In Group 3, GCD decreased to 205.88 ± 25.04 and 139.54 ± 17.37 measured with LSCM and IC, respectively (p < 0.05). Month six. Mean GCD did not change in Group 1 (p > 0.05) whereas it decreased in Group 2 (p < 0.05), compared to month 1. In Group 3, GCD further decreased to 166.32 ± 22.31 and 120.76 ± 11.66, measured with LSCM and IC, respectively (p < 0.05); in Group 4, mean GCD did not change during the study period (p > 0.05).

CONCLUSIONS

Treatment with PF tafluprost was associated with an increase in conjunctival GCD in glaucomatous eyes naïve for therapy. Further studies are mandatory to verify this finding because its validation may have important consequences in the medical management of glaucoma.

Effect of chronic anti-glaucoma medications and trabeculectomy on tear osmolarity

PURPOSE

To evaluate the tear film osmolarity (TFO) and ocular surface clinical signs and symptoms in chronically medicated glaucoma patients and post-trabeculectomy patients.

METHODS

This is a single-center, prospective case-controlled study. One-hundred and thirty eyes of 130 participants aged ≥ 45 years were included (49 normal controls, 50 glaucoma patients on chronic preserved anti-glaucoma medication ≥ 6 months, and 31 post-trabeculectomy patients not on medication ≥ 6 months). TFO, tear break-up time (TBUT), Schirmer's test I and dry eye symptoms were evaluated. Data from both groups of glaucoma patients were compared with age and sex-matched controls. Logistic regression was performed to calculate the odds ratios.

RESULTS

Mean TFO in the three groups were 301.4 ± 7.7, 307.0 ± 9.3, and 307.4 ± 11.6 mOsm/l, respectively. Compared with normal controls, chronically medicated glaucoma patients and post-trabeculectomy patients were more likely to have a raised TFO, with odds ratios (95% CI) of 4.43 (1.74-11.32) and 2.76 (1.02-7.94), respectively. Both groups of glaucoma patients were also more likely to experience dry eye symptoms, with ORs of 4.72 (1.92-11.59) and 4.24 (1.54-11.72). There was no significant difference in TFO and symptoms between both groups of glaucoma patients, and in TBUT and Schirmer's test across all three groups.

CONCLUSIONS

Patients on chronic topical anti-glaucoma medication and post-trabeculectomy patients were more likely to have raised TFO and dry eye symptoms, suggesting significant ocular surface disease. Glaucoma practitioners should be aware that dry eye symptoms and raised TFO may occur in the absence of TBUT and Schirmer's test abnormality.

CX3CL1 expression in the conjunctiva is involved in immune cell trafficking during toxic ocular surface inflammation

Inappropriate expression of the chemokine CX3CL1 is reportedly known to act on inflammatory conditions in extraocular immune diseases. We studied the expression and effects of CX3CL1 in human patients, cultured human conjunctival cells, and transgenic mice exposed to benzalkonium chloride (BAC), a commonly used preservative in ophthalmic medications despite its proinflammatory properties, to determine whether CX3CL1 is involved in conjunctival inflammation. We report that CX3CL1 expression is increased in the conjunctiva of patients receiving BAC-containing medication, and correlates with clinical inflammation. BAC enhances the production of CX3CL1 in a conjunctival epithelial cell line, through the tumor-necrosis factor-α pathway, which attracts specific leukocyte subsets. In vivo, BAC-induced macrophage infiltration and subsequent inflammation of the conjunctiva is decreased in CX3CR1-deficient mice as compared with CX3CR1(+/+) controls. This translational study opens new avenue to investigate ocular surface disorders by focusing on chemokine-related inflammation and immune cell trafficking in the ocular conjunctival mucosa.

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.

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 Surface Changes in Primary Open Angle Glaucoma with Long Term Topical Anti Glaucoma Medication

BACKGROUND

Topical life long anti glaucoma medication forms the mainstay of treatment of primary open angle glaucoma. Their long term usage can cause changes in conjunctival epithelium.

METHODS

Hundred cases of primary open angle glaucoma were divided into four groups of 25 patients each. Each group was put on Timolol, Pilocarpine, Brimonidine and Latanoprost respectively. Ocular surface changes were monitored using Schirmer's test, tear film break up time (BUT) and conjunctival impression cytology.

RESULT

Altered Schirmer's test value was seen in 40% of patients and reduced tear film BUT values in 26%, at the end of one year. These changes were more in patients treated with timolol. Changes in conjunctival cytology such as decrease in goblet cell density, squamous metaplasia and presence of inflammatory cells were seen in significant number of patients at the end of one year treatment. There was direct relation of duration of treatment to various ocular surface changes.

CONCLUSION

Ocular surface changes are seen in significant number of patients of primary open angle glaucoma at the end of one year follow up with topical anti glaucoma therapy. Conjunctival impression cytology is a non invasive technique to monitor these changes.

[Ocular toxicity of benzalkonium]

In order to meet the requirements of the pharmacopeia, ophthalmic preparations have to be manufactured in conditions that can secure their sterility before use and can prevent the development of micro-organisms after opening of the vial. The addition of an appropriate preservative is a way to meet this requirement. However, in addition to their lack of efficacy in certain conditions, they can be problematic in terms of formulation, stability and interaction with the packagings. Furthermore, their daily and repeated use in chronic pathologies such as glaucoma, dry eye or allergy has revealed their nuisance. Moreover, the recognition of certain parameters such as life quality and therapeutic observance has strengthened the proofs that have already been clinically shown. The review of the experimental and clinical data already published about the toxicity of the preservatives shows that almost every ocular structure is affected to various extents. From the first assumption data to preclinical and clinical proofs, this article highlights the evolution of the understanding process towards the toxic role of preservatives.

Efficacy and patient tolerability of travoprost BAK-free solution in patients with open-angle glaucoma and ocular hypertension

The medical treatment of glaucoma has evolved significantly over the past several decades. The main driving forces behind this evolution are the safety profiles and efficacy of these medications. Prostaglandin (PG) analogues are shown to be superior to older drugs in both efficacy and tolerability. Though there are much fewer side effects that manifest after using PG analogues, the adherence and compliance to medication regimens are surprisingly lower than expected. A commonly sited reason is the ocular irritation and inflammation with these medications. Much of this inflammation can be attributed to the preservative, benzalkonium chloride (BAK). The chronic clinical and subclinical inflammation becomes increasingly detrimental when filtration surgery fails from bleb fibrosis secondary to this hypercellularity. A BAK-free formulation of a PG analogues recently became available. BAK-free travoprost is reviewed here. It has demonstrated equal efficacy and less ocular surface toxicity than its preserved counterparts. It is expected to serve as an instrumental resource in managing ocular hypertension and glaucoma in patients who demonstrate significant sensitivity to BAK. More randomized, controlled, double-blind studies are encouraged to evaluate its improved safety and tolerability.

Effect of chronic topical glaucoma medications on aerobic conjunctival bacterial flora

PURPOSE

To investigate whether the chronic topical medications affect aerobic conjunctival bacterial flora of patients with glaucoma and to compare their findings with the findings of the controls.

METHODS

Eighty-one patients and 67 healthy control subjects participated in this case-control study. Duplicate conjunctival swab specimens were collected from each patient at the microbiology laboratory and were investigated for the presence of aerobic bacteria. All bacterial species from isolated colonies were identified.

RESULTS

Thirty seven (45.7%) of the 81 patients and 25 (37.3%) of 67 controls had positive conjunctival cultures. Coagulase-negative Staphylococcus was the most commonly isolated bacterial species in both groups. There were no statistically significant differences between the prevalence of other conjunctival cultures testing positive for any of the isolated organisms. The patients were also evaluated with respect to the presence of a systemic illness. Age, sex, presence of diabetes and asthma, duration of antiglaucomatous medication, and number of medications used did not have an effect on culture positivity in both groups when evaluated by logistic regression model.

CONCLUSIONS

The conjunctival culture positivity was higher in patients with glaucoma than in the healthy controls and in patients with diabetes than in patients without diabetes, although both were statistically insignificant. Aerobic conjunctival flora of the patients using topical glaucoma medications and the controls did not differ. Further studies are needed to comment on the clinical importance of these findings.

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.

Evaluation of toxicity of commercial ophthalmic fluoroquinolone antibiotics as assessed on immortalized corneal and conjunctival epithelial cells

PURPOSE

To evaluate the toxicity of a variety of the fluoroquinolone antibiotics on the ocular surface by using tissue culture models of corneal epithelial cells and conjunctival epithelial cells.

METHODS

Immortalized conjunctival (CCC) and human corneal (HCE) epithelial cells were grown and when confluent the cells allowed to air dry for 1 hour. Medium was then replaced with 100 microL of one of the following: 1) Vigamox [moxifloxacin (0.5%: MX)]; (2) Zymar [gatifloxacin (0.3%: GA)]; 3) Quixin [levofloxacin (0.5%: LE)]; 4) Ocuflox [ofloxacin (0.3%: OF)]; 5) Ciloxan [ciprofloxacin (0.3%: CP)]; 6) medium (viable control); 7) "normal"/physiologic saline; 8) formalin (dead control). After one hour, 150 microL of MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazonium bromide was added and incubated for 4 hours. After decanting, precipitate was dissolved in 150 microL of isopropanol. Absorbance was determined at 572 nm.

RESULTS

The lowest amount of cell death was associated with the viable control. All ophthalmic preparations showed both corneal and conjunctival cell toxicity. Aside from the viable control, normal saline showed the next lowest amount of toxicity. Of the topical ocular antibiotics tested, MX showed the least amount of toxicity. All of the other antibiotics tested were statistically indistinguishable from each other.

CONCLUSIONS

All of the topical ocular antibiotics tested showed evidence of both corneal and conjunctival toxicity (MX < OF < or = LE < or = CP < or = GA), although only MX was statistically significant. Whether this finding reflects on in vivo wound healing remains to be determined. This model provides a rapid and cost-effective method to screen for surface toxicity of topical agents.

Phospholipases A2 in normal human conjunctiva and from patients with primary open-angle glaucoma and exfoliation glaucoma

BACKGROUND

Chronic situations like long-term use of topical medications induces conjunctival inflammation and is also a significant risk factor for failure of filtering surgery. We evaluated conjunctival expression of group IIA secretory PLA(2) (sPLA(2)-IIA), group V secretory PLA(2) (sPLA(2)-V), calcium-independent PLA(2) (iPLA(2)) and cytosolic PLA(2) (cPLA(2)).

METHODS

Samples were obtained from non-glaucomatous patients (control subjects), and patients with either primary open-angle glaucoma (POAG) or exfoliation glaucoma (ExG). All the glaucoma patients had been treated with antiglaucomatous medication, and underwent deep sclerectomy surgery. Antibodies against sPLA(2)-IIA, sPLA(2)-V, iPLA(2) and cPLA(2) were used for immunohistochemical staining of frozen tissue sections.

RESULTS

In the human conjunctiva of non-glaucomatous patients, immunostaining of sPLA(2)-IIA, sPLA(2)-V or cPLA(2) was low and positively stained cells were mainly localized in the surface of the epithelium. In contrast, iPLA(2) was found to predominate in human normal conjunctiva and it demonstrated strong labeling throughout the epithelium. The stromal staining of iPLA(2) was weak. Expression of sPLA(2)-IIA was significantly increased in stromal fibers of patients with POAG or ExG. No changes were found in levels of sPLA(2)-V, iPLA(2) or cPLA(2) between the patient groups and controls.

CONCLUSIONS

These findings demonstrate that sPLA(2)-IIA, sPLA(2)-V, iPLA(2) and cPLA(2) are expressed in the conjunctiva of non-glaucomatous patients. In the epithelium, sPLA(2)-IIA, sPLA(2)-V, and cPLA(2) may participate in protection against risks caused by mechanical wear and tear stress whereas iPLA(2) may regulate remodeling and maintenance of membrane phospholipids. sPLA(2)-IIA may also have the important role in the degradation of bacteria. In conjunctival stroma of POAG and ExG patients, sPLA(2)-IIA may play a role in the development of scar tissue after glaucoma filtration surgery.

Effects of latanoprost, timolol and GLC756, a novel dopamine D(2) agonist and D(1) antagonist on LTC(4) release after rat mast cell activation

PURPOSE

Mast cells participate in ocular allergic inflammation by releasing biologically active mediators. Leukotrienes are released from activated mast cells via an IgE-dependent mechanism, and play a crucial role in ocular allergic inflammation. In this study, the effect of three topical antiglaucoma drugs, that is, latanoprost, timolol and GLC756, a novel dopamine D(2) agonist and D(1) antagonist, on leukotriene C(4) (LTC(4)) release after rat mast cell activation was examined.

METHODS

A rat basophilic leukaemia RBL-2H3 mast cell line was activated via IgE/anti-IgE. Rat mast cells were incubated with latanoprost, timolol, or GLC756 at concentrations of 0.1, 1, 10 and 30 microM. LTC(4) concentration in supernatant was assessed 5 h post activation by EIA.

RESULTS

Compared with controls, timolol showed no relevant effect on LTC(4) release, 5 h after mast cell activation. Latanoprost and GLC756, in contrast, revealed an inhibitory effect on LTC(4) release, which was dose-related and statistically significant at the concentrations of 10 and 30 microM.

CONCLUSION

The results of this study suggest that timolol has no significant influence on LTC(4) release from activated mast cells. By contrast, latanoprost and GLC756 inhibited LTC(4) release, suggesting a possible anti-inflammatory effect on ocular allergic inflammatory processes in topical glaucoma medication.

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.

Effect of GLC756, a novel mixed dopamine D1 receptor antagonist and dopamine D2 receptor agonist, on TNF-alpha release in vitro from activated rat mast cells

Tumor necrosis factor-alpha (TNF-alpha) is released from activated mast cells via an IgE-dependent mechanisms, and plays a crucial role in ocular allergic inflammation. This study examined the influence of three antiglaucoma drugs differing in their chemical structure and pharmacological profile (i.e. latanoprost, timolol, GLC756) on TNF-alpha release from activated rat mast cells. A rat basophilic leukemia mast cell line (RBL-2H3) was activated via IgE/anti-IgE. Rat mast cells were incubated with latanoprost, timolol, GLC756 or betamethasone (positive control) at concentrations of 0.1, 1, 10 and 30 microM. TNF-alpha concentration in supernatant was measured by ELISA 5 h post-activation. Compared to controls, the prostaglandin derivative latanoprost and the beta-blocker timolol in the concentration range 0.1-30 microM, had no significant effect on TNF-alpha release from rat mast cells measured 5h after activation. By contrast, the dopaminergic drug GLC756 compared to controls in the concentration range 1-30 microM significantly inhibited TNF-alpha release from activated rat mast cells in a concentration-dependent manner. The positive control betamethasone inhibited TNF-alpha release almost completely at all concentrations tested. In conclusion, the results of this study suggest that latanoprost and timolol do not reduce inflammation triggered by activated mast cells. By contrast, the dopaminergic drug GLC756 inhibited TNF-alpha release from activated mast cells, suggesting an palliative potential of dopaminergic compounds on allergic conjunctivitis in topical glaucoma medication.

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.

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.

Brimonidine and timolol fixed-combination therapy versus monotherapy: a 3-month randomized trial in patients with glaucoma or ocular hypertension

PURPOSE

The aim of this study was to compare the safety and intraocular pressure (IOP)- lowering efficacy of a fixed combination of brimonidine 0.2% and timolol 0.5% (fixed brimonidine/ timolol) versus each drug used as monotherapy.

METHODS

Patients with glaucoma or ocular hypertension were randomized to receive fixed brimonidine/timolol BID (n = 385), brimonidine 0.2% TID (n = 382), or timolol 0.5% BID (n = 392) in a multicenter, double-masked study. The primary outcome measure was decrease from baseline IOP.

RESULTS

Over all follow-up measurements, the mean decrease from baseline IOP ranged from 4.9 to 7.6 mmHg with brimonidine/timolol, from 3.1 to 5.5 mmHg with brimonidine, and from 4.3 to 6.2 mmHg with timolol. Mean IOP reductions from baseline were significantly larger with fixed brimonidine/timolol than with timolol at all follow-up measurements (P < or = 0.026); the difference was greater than 1.5 mmHg at 10 AM (peak effect for each treatment). Mean IOP reductions from baseline were significantly larger with fixed brimonidine/ timolol than with brimonidine at 8 AM, 10 AM, and 3 PM (P < 0.001); the difference was greater than 1.5 mmHg. The rate of discontinuations owing to adverse events was 3.6% in the fixed timolol/brimonidine group.

CONCLUSIONS

The fixed combination of brimonidine and timolol was well-tolerated and provided significantly better IOP control compared with either brimonidine or timolol used alone.

Comparison of Corneal Surface Effects of Gatifloxacin and Moxifloxacin Using Intensive and Prolonged Dosing Protocols

PURPOSE

To compare the effects of the commercial formulations of moxifloxacin and gatifloxacin on rabbit corneal epithelium using two dosing protocols: high-frequency dosing for bacterial keratitis and cataract surgery prophylaxis.

METHODS

Forty eyes of 20 New Zealand white rabbits were randomized to receive topical gatifloxacin, topical moxifloxacin, or no drops as controls. Eighteen eyes received 1 drop of antibiotic every 5 minutes for 15 minutes followed by 1 drop every 15 minutes for 4 hours. Twelve eyes received topical gatifloxacin or topical moxifloxacin 4 times a day for 10 days. Rabbits were euthanized, eyes enucleated, and the corneas separated, washed, and fixed; scanning electron microscopy was performed. Photomicrographs of three separate areas from the corneal apex were taken at x1200 and x3000 for each cornea. Two masked, experienced examiners then graded the corneal epithelial damage.

RESULTS

In the high-frequency dosing group, mean corneal damage score for eyes treated with gatifloxacin was 1.593, that for moxifloxacin was 1.407, and control was 1.000. No statistically significant difference was found between gatifloxacin and moxifloxacin (P = 0.41), gatifloxacin and control (P = 0.14), or moxifloxacin and control (P = 0.23). In the cataract surgery prophylaxis group, mean corneal damage scores for eyes treated with gatifloxacin was 1.167, that for moxifloxacin was 1.368, and control was 1.000. No statistically significant difference was found between gatifloxacin and moxifloxacin (P = 0.23), gatifloxacin and control (P = 0.08), or moxifloxacin and control (P = 0.23).

CONCLUSION

Despite differences in formulations, with short-term dosing neither gatifloxacin nor moxifloxacin appears to be toxic to the corneal epithelium in this rabbit model.

Comparison of Preoperative Conjunctival Bacterial Flora in Patients Undergoing Glaucoma or Cataract Surgery

PURPOSE

To assess differences in conjunctival bacterial flora between patients undergoing glaucoma and cataract surgery.

PATIENTS AND METHODS

A prospective study comparing conjunctival bacterial cultures obtained from 339 patients undergoing either cataract (n = 258) or glaucoma (n = 81) surgery. All cultures were acquired during the preoperative visit, approximately three to seven days prior to surgery. The culture samples were inoculated onto blood and chocolate agar, as well as blood culture broth media. All bacterial isolates were identified and statistical analyses were performed to determine if there were differences in flora between the eyes undergoing cataract versus glaucoma surgery.

RESULTS

Two hundred fifteen of 258 eyes (83%) undergoing cataract surgery were found to have positive bacterial growth, compared with 62 of 81 eyes (77%) of those undergoing glaucoma surgery (P = 0.2246). Coagulase-negative Staphylococci, the most common bacterial isolate, was cultured from 167 eyes (65%) in the cataract group and 42 (52%) in the glaucoma group (P = 0.0514). Among all bacterial isolates, only Corynebacterium species was found to be statistically different between the two patient groups with 92 (36%) and 11 (14%) eyes testing positive in the cataract and glaucoma groups, respectively (P = 0.0003).

CONCLUSIONS

There was no statistically significant difference in the proportion of conjunctival culture samples testing positive for bacterial growth in eyes undergoing glaucoma surgery compared with those undergoing cataract surgery. Glaucoma medications, or their preservatives, do not appear to significantly alter conjunctival flora. Techniques used for endophthalmitis prophylaxis prior to cataract surgery are likely appropriate for glaucoma surgery as well.

Reducing intraocular pressure: is surgery better than drugs?

Reducing IOP is presently the evidence based, most accepted and most practised therapeutical approach for glaucoma patients. Currently topical ocular hypotensive medications, with its different classes, as well as filtering surgery (trabeculectomy and non-penetrating glaucoma surgery) are in the forefront of therapeutic modalities for IOP reduction. This article looks at the potential advantages and disadvantages of topical medications versus filtering surgery. It does not directly address the question of initial treatment of glaucoma, or what is the better treatment of glaucoma, as other review articles had, but rather looks in a more specific on the pros and the cons of each in relation to IOP reduction. In other words this article deals with the situation once the decision has been made to reduce IOP.

Evaluation of the Corneal Effects of Topical Ophthalmic Fluoroquinolones Using In Vivo Confocal Microscopy

PURPOSE

To compare the effects of several fluoroquinolone antibiotics on the corneal epithelium and stroma using in vivo confocal microscopy.

METHODS

Five antibiotic solutions were evaluated: 1) 0.3% ofloxacin (Oflox) solution with 0.005% benzalkonium chloride (BAC); 2) 0.3% gatifloxacin (Gati) solution with 0.005% BAC; 3) 0.3% ciprofloxacin (Cipro) solution with 0.006% BAC; 4) 0.5% levofloxacin (Levo) with 0.005% BAC; and 5) 0.5% moxifloxacin (Moxi) solution with no BAC. Preservative-free artificial tears (Tears) were used as a control. New Zealand white rabbits were used for this study (six per solution group). Ten days prior to exposure to any solution, central corneal epithelial thickness and stromal thickness were measured using in vivo confocal microscopy through focusing. Images of the superficial epithelium were also acquired. Both eyes of each rabbit then received one drop of the assigned solution six times the first day and then four times per day for 6 days. On day 7, in vivo confocal microscopy was repeated.

RESULTS

A significant decrease in epithelial thickness was induced by 7 days of exposure to Levo, Gati, Oflox, and Cipro (P < 0.05, two-way repeated-measures ANOVA, Tukey test). Tears and Moxi, which do not contain BAC, did not induce significant changes in epithelial thickness. No significant changes in stromal thickness were detected (P = 0.266), and no keratocyte activation was observed for any of the solutions evaluated.

CONCLUSION

We have previously used confocal microscopy to establish a correlation between epithelial thinning (due to superficial cell loss) and slight ocular irritation. The results of this study suggest that Moxi induces less damage to the corneal epithelium than other antibiotic solutions, perhaps because it does not contain BAC.

Assessing the cost-effectiveness of switching from a beta-blocker to latanoprost in the treatment of ocular hypertension

Glaucoma is a pathological condition whose most important risk factor is increased intraocular pressure (IOP). The medical treatment of glaucoma essentially consists of compounds that are able to decrease the IOP. The compounds discussed in this review act in a different way, beta-blockers mainly inhibit the production of aqueous humor, whereas latanoprost decreases the resistance in the outflow channels. beta-Blockers are compounds with a well-known efficacy and safety profile and they are fairly inexpensive. Their systemic and local side effects are mainly cardiovascular and pulmonary adverse events, dry eye and keratopathy. Latanoprost, which has recently been introduced into the market, has been shown to be equally as effective, or better in lowering IOP in patients than timolol, although it is more expensive. Systemic reported side effects are anecdotal; local hyperaemia, keratopathy, hypertrichosis, increased pigmentation of eyelashes and iris, uveitis and cystoid macular oedema have been reported. A comparison of costs reveals that a 1-year therapy with timolol ophthalmic solution starts from 11.00 Euros and can reach 146.00 Euros for the most expensive preservative-free 1-day dispenser packages (approximately 13.5 times higher). For latanoprost once-daily administration, the cost for 1 years therapy is 98.55 Euros, approximately six times higher than generic or brand 0.5% timolol applied twice-daily. What are the factors influencing a change in therapy from beta-blockers to latanoprost? The only good reason is represented by a further deterioration in the visual field. This may occur, despite a significant reduction in IOP, because the reached IOP is not sufficient enough to avoid further deterioration because the patient's work or social activities do not allow a correct daily dosage of the compound (bad compliance); or as a result of treatment suspension, because of the development of systemic and/or local side effects. Changes in therapy must always be related to a failing control of the disease, as any therapeutic modification leading to an increase in the number of visits and additional examinations, consequently enhances the costs.

Ocular surface impression cytology

Impression cytology, either using cellulose acetate strips or the Biopore membrane device, is a simple, noninvasive technique that aids in the diagnosis of several disorders of the ocular surface. These disorders include ocular surface squamous neoplasia, dry eye syndrome, limbal stem-cell deficiency, specific viral infections, vitamin A deficiency, allergic disorders, conjunctival melanosis, and malignant melanoma. Another advantage is the preservation of limbal stem cells, which occur in the basal layer of the limbal epithelium and are responsible for renewal of the corneal epithelium. The Biopore membrane device is particularly user friendly, with little expertise required and adequate specimens obtained in a very high percentage of cases. The most common applications in diagnostic ocular pathology are:(i) primary diagnosis and follow-up of ocular surface squamous neoplasia, including after therapy with topical mitomycin C. The sensitivity is high (78-87%); and (ii) dry eye syndrome where squamous metaplasia and/ or hyperkeratosis are noted. Certain limitations of the technique for diagnosis of squamous neoplasia include the fact that dysplasias are often keratinizing and may yield very few or even no dysplastic cells with impression cytology. Secondly, no definite cytologic criteria reliably distinguish invasive SCC of ocular surface from in situ disease. Other applications include the rapid specific diagnosis of ocular surface infections with herpes simplex, adeno-, and varicella zoster viruses. Impression cytology samples may also be used to obtain mRNA, cells for phenotyping by flow cytometry, and proteins for Western blotting for research studies.