The Ocular Surface in Glaucoma

Ocular surface disease signs and symptoms of glaucoma patients and their relation to glaucoma medication in Finland

PURPOSE

To evaluate the prevalence of ocular surface disease (OSD) signs and symptoms of glaucoma patients in private clinics in relation to topical glaucoma treatment and to compare them to non-glaucomatous population.

METHODS

A multicenter, cross-sectional study consisting of private ophthalmology clinic visits in southern Finland. Glaucoma patients had a diagnosis of primary open-angle glaucoma, pseudoexfoliation glaucoma, pigmentary glaucoma, or treated ocular hypertension. Control patients had no prior or current use of glaucoma medication. Recorded parameters included OSD signs and symptoms, used glaucoma medications during the past 6 months, and the product name, type, and duration of used antiglaucoma drugs.

RESULTS

Glaucoma patients (n = 564) showed higher severity of OSD sign parameters excluding Schirmer's test, as well as increased dry eye sensation compared to controls (n = 51). Beta-blockers and preservative-free prostaglandins had the smallest effect on all parameters. The increasing number of active compounds and administered eye drops per day showed an association with increasing severity of OSD signs, as well as dry eye and foreign body sensation. Duration of glaucoma medication showed no significant association with OSD signs or symptoms.

CONCLUSION

Glaucoma patients show higher prevalence of OSD signs and dry eye sensation compared to non-glaucomatous population. The use of preserved glaucoma medication, as well as high number of active compounds and eye drops increase the severity of these parameters. There are significant differences between the types of glaucoma medication used, and therefore the selection of them is important especially in patients suffering from OSD.

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.

Preservative-free versus preserved brimonidine %0.15 preparations in the treatment of glaucoma and ocular hypertension: short term evaluation of efficacy, safety, and potential advantages

Purpose: To compare the efficacy, safety, and potential advantages of the preservative-free versus preserved brimonidine %0.15 preparations in patients with primer open-angle glaucoma (POAG) or ocular hypertension (OHT).Methods: Forty-two eyes of the 21 treatment-naive patients with POAG or OHT were enrolled in this study. Eyes were randomly assigned to receive brimonidine-purite 0.15% or preservative-free brimonidine 0.15% two times daily. Efficacy of the two eye drops was assessed by measuring the intraocular pressure (IOP) at 9-10 am at baseline and week 4. Safety and potential advantages of the drops were evaluated at weeks 4 in terms of ocular symptoms and tear parameters. Ocular symptom values of the patients were evaluated with a scale of 0-4 (0 = no discomfort and 4 = severe discomfort).Results: Both of the brimonidine tartrate formulations resulted in statistically similar IOP reduction (preserved formulation; -5.2 mmHg [22.9% reduction] preservative-free formulation; -5.7 mmHg [24.1% reduction], p = 0.37). It was found that brimonidine tartrate formulations with and without topical preservatives did not produce a statistically significant difference in pain, stinging, and blurred vision at the upon instillation (p > 0.05). However, the burning sensation was significantly higher in the preservative-free formulation at the first instillation compared to the preserved formulation (p = 0.01). Also, there was no statistically significant difference between the two formulations in terms of symptoms (itching, burning, tearing, stinging, and photophobia) and tear parameters during the day (p > 0.05).Conclusions: Although topical preservative-free brimonidine tartrate treated eyes had a more burning sensation at the first drop, the two formulations were similar in terms of ocular tolerability in the short term period. Also, both formulations were found to reduce IOP at a similar rate.

N-hydroxymethylglycinate with EDTA is an efficient eye drop preservative with very low toxicity: an in vitro comparative study

PURPOSE

Preservatives are used in multi-dose ophthalmic topical medications in order to prevent contamination by bacteria and fungi. However, prolonged use of preserved eye drops, as it may happen in dry eye or glaucoma, may damage cells of the ocular surface. Therefore, an important goal is to find preservatives with low toxicity which are mild to host cells, still able to prevent drug contamination so to maintain their sterility and efficacy. Hence, aim of this study has been to compare the relative toxicity on a rabbit corneal cell line of a new preservative, made by the association of N-hydroxy-methyl-glycinate (NIG) with disodium-ethylene diamine tetra-acetate (EDTA), with other known and widely used eye-drops preservatives.

MATERIALS AND METHODS

Rabbit corneal cells (SIRC) were tested either in 96-well plates or in suspension culture. Treatments with preservatives (used at known bacteriostatic concentrations) included: benzalkonium chloride (BAK), polyquaternium-1 (PQ-1), sodium perborate (SP: NaBO_{3 *} H₂O), and NIG ± EDTA at different concentrations (0.001% and 0.002%), and different treatment times (from 30 minutes to 120 hours). At the end of treatment, cell survival was evaluated by a specific spectrophotometric method through the metabolic conversion of MTT [3-(4,5-dimethylthiazol-2-yl) 2, 5-diphenyltetrazolium bromide] into formazan crystals.

RESULTS

Almost no cell toxicity was evident for NIG and SP at either concentration (0.001% or 0.002%), while a low toxicity was observed for PQ-1 (62% at the highest dose at 120 hours). BAK, as expected, showed the highest toxicity (60-80% at 30 minutes, and over 90% from eight hours onward). EDTA 0.1% alone or in combination with NIG 0.002%, showed no toxicity at 24 hours, and even resulted in cell growth promotion (46% and 38%, respectively), after 48 hours of treatment.

CONCLUSIONS

These data show that the new preservative NIG/EDTA, at doses known to have effective antimicrobial properties, has a very low toxicity on corneal cells, and so it can be safely used in multi-dose eye drops.

In Vivo Effects of Preservative-free and Preserved Prostaglandin Analogs: Mouse Ocular Surface Study

Purpose

Chronic use of topical hypotensive agents induces several side effects caused by preservatives. The purpose of this study was to evaluate the effects of prostaglandin analogs with varying concentrations of benzalkonium chloride (BAC), preservative-free (PF), and alternative preservatives on mouse corneal tissue.

Methods

Thirty-five, 8- to 10-week-old female C57BL/6 mice (five mice for each group) were used for this study. To the control group, we applied normal saline, and to each drug-treated group we applied 0.02% BAC, bimatoprost 0.01% (with BAC 0.02%), latanoprost 0.005% (with BAC 0.02%), travoprost 0.004% (with 0.001% polyquad) or tafluprost 0.0015% with/without 0.001% BAC, once a day (9 p.m.) for 4 weeks. Corneal fluorescein staining was evaluated in all groups. After harvest, the corneal tissues were embedded in paraffin and then Hematoxylin-Eosin stain was performed for histopathological examination. Immunofluorescence staining was done against TNF-α, IL-6, HLA DR, pJNK, and pAkt.

Results

In corneal fluorescein staining, severe punctate epithelial keratitis was seen in the groups of 0.02% BAC, 0.02% BAC containing bimatoprost 0.01% and latanoprost 0.005%. The surface desquamation, irregular surface, loss of cell borders, anisocytosis and stromal shrinkage were observed in the groups of BAC-containing eye drops. Moreover, the groups treated with BAC-containing eye drops have high inflammatory markers, significantly decreased cell viability-related signal, pAkt, and higher apoptosis-inducing signal, pJNK, than the control group. On the other hand, travoprost 0.004% and PF tafluprost 0.0015% have less cellular morphologic changes, lower inflammation, and higher cellular viability than BAC-containing formulations.

Conclusions

Corneal damage, increased inflammation and apoptosis and low cell viability were observed in BAC-containing groups. PF or alternatively preserved glaucoma medications seem to be a reasonable and viable alternative to those preserved with BAC.

Effect of 0.3% Hydroxypropyl Methylcellulose/Dextran Versus 0.18% Sodium Hyaluronate in the Treatment of Ocular Surface Disease in Glaucoma Patients: A Randomized, Double-Blind, and Controlled Study

PURPOSE

To compare the efficacy and safety of 0.3% hydroxypropyl methylcellulose/dextran (HPMC/dextran) and 0.18% sodium hyaluronate (SH) in the treatment of ocular surface disease in patients using antiglaucoma drugs containing preservatives.

METHODS

This was a double-blind, randomized, parallel-group study in 70 glaucoma patients with Ocular Surface Disease Index (OSDI) score greater than 20 points and/or presence of ocular signs. Patients were randomized to receive either preservative-free 0.3% HPMC/dextran (n=35) or preservative-free 0.18% SH (n=35). Treatment was 1 drop in each eye, 4 times a day. Data were collected at baseline, at day 7 and day 28.

RESULTS

The groups were homogeneous at baseline. At day 28, both treatments showed significant improvements (P<0.05) in the mean OSDI score, lid skin and lid margin inflammation, conjunctival injection, and expressibility of meibomian glands, corneal staining score, fluorescein tear breakup time (FBUT), and Schirmer I test. However, the mean OSDI score, lid margin inflammation and conjunctival injection showed significant improvements (P<0.05) in the SH group at days 7 and 28, compared to the HPMC/dextran group. FBUT and the Schirmer I test also showed significant improvements (P<0.05) in the SH group compared to the HPMC/dextran group, at day 28. No adverse reactions were observed in either group.

CONCLUSIONS

Preservative-free artificial tear, 0.3% HPMC/dextran, and 0.18% SH, caused a significant relief of the ocular surface disease in glaucoma patients. However, 0.18% SH led to a greater improvement in ocular signs and symptoms than 0.3% HPMC/dextran.

Evaluation of ocular surface disease in patients with glaucoma

PURPOSE

To evaluate the subjective and objective measures of ocular surface disease in patients with glaucoma.

DESIGN

Cross-sectional study.

PARTICIPANTS

Sixty-four glaucoma subjects with bilateral visual field (VF) loss and 59 glaucoma suspects with normal VFs.

METHODS

Consecutive patients were recruited prospectively from the Wilmer Eye Institute Glaucoma Clinic.

MAIN OUTCOME MEASURES

Tear film breakup time (TBUT), corneal staining score (0-15), and Schirmer's test results were included as objective metrics, whereas the Ocular Surface Disease Index (OSDI) questionnaire was administered to assess symptoms. Total OSDI score, vision-related subscore (derived from questions about vision and task performance), and discomfort-related subscore (derived from questions about ocular surface discomfort) were calculated for each subject.

RESULTS

Seventy-five percent (48/64) of glaucoma subjects and 41% (24/59) of glaucoma suspects were receiving topical medications. The corneal staining grade was greater in glaucoma subjects than in glaucoma suspects (6.4 vs. 4.1; P<0.001), but groups did not differ with regard to TBUT or Schirmer's results (P>0.20 for both). Multivariate regression models showed that topical glaucoma therapy burden was associated with a significantly higher total corneal staining grade (β, +0.9 for each additional glaucoma drop; 95% confidence interval [CI], 0.5-1.3; P<0.001), but not with TBUT or Schirmer's results (P>0.20 for both). Glaucoma subjects had significantly higher total OSDI scores than glaucoma suspects (16.7 vs. 7.9; P<0.001). This largely was the result of higher vision-related subscores in the glaucoma group (11.1 vs. 3.3; P<0.001). Ocular discomfort-related subscores, however, were similar in both groups (5.7 vs. 4.6; P = 0.30). In multivariate analyses, each 5-decibel decrement in better-eye VF mean deviation was associated with a 4.7-point increase in total OSDI score (95% CI, 1.9-7.5; P = 0.001) and a 3.7-point increase in the vision-related subscore (95% CI, 1.7-5.6; P<0.001) but did not predict a higher discomfort-related subscore (β, 1.1 point; P = 0.07). Topical glaucoma therapy burden was not associated with higher total OSDI score or vision- or discomfort-related subscore (P>0.20 for all).

CONCLUSIONS

Glaucoma is associated with significant ocular surface disease, and topical glaucoma therapy burden seems predictive of corneal staining severity. However, OSDI is a poor metric for capturing ocular surface disease in glaucoma because symptoms seem to be related largely to VF loss.

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.

[Arguments against pressure-lowering treatment of ocular hypertension. Prophylactic treatment is unnecessary]

The main argument against a pressure-lowering treatment for patients with ocular hypertension (OHT) is the principle of "first do no harm". The imprecision of intraocular pressure (IOP) measurements and the fact that increased IOP is only a risk factor for glaucoma raise major doubts on a clinical definition of OHT. The use of IOP-lowering treatment in the absence of functional or morphological glaucomatous changes should only be initiated if the IOP is very high (>32 mmHg). If the IOP is between 21 and 32 mmHg the glaucoma conversion risk of the individual patient should be estimated. The risk factors as proven in major prospective trials (OHTS/EGPS) should be assessed using the risk calculator. Only patients with a high risk (>13%) of conversion profit from prophylactic IOP-lowering treatment. For all patients with intermediate or low risk of conversion the potential side-effects (local and systemic) of the treatment outweigh the possible benefit, so that the principle of "watchful waiting" is the best for patients with OHT. If morphological or functional progression is observed IOP-lowering treatment should be started immediately.

Polyquad-preserved travoprost/timolol, benzalkonium chloride (BAK)-preserved travoprost/timolol, and latanoprost/timolol in fixed combinations: a rabbit ocular surface study

INTRODUCTION

The aim of this study was to use a validated acute rabbit model to test the toxicity of a novel formulation of fixed-combination travoprost 0.004%/timolol 0.5% ophthalmic solution, which contains the antimicrobial preservative polyquaternium-1 (PQ), compared with the commercial formulation of fixed combinations travoprost 0.004%/timolol 0.5% ophthalmic solution and latanoprost 0.005%/timolol 0.5% ophthalmic solution, which both contain the preservative benzalkonium chloride (BAK).

METHODS

Adult male New Zealand albino rabbits (n=24) were randomly divided into four groups. Phosphate-buffered saline (PBS), travoprost/timolol PQ, travoprost/timolol BAK, or latanoprost/timolol BAK were instilled onto rabbit eyes one drop, 15 times at 5 minute intervals. The ocular surface reactions were investigated at hour 4 and day 1 using slit lamp examination; in-vivo confocal microscopy (IVCM) for cornea, limbus, and conjunctiva-associated lymphoid tissue (CALT); conjunctival impression cytology; and standard immunohistology in cryosections for detecting CD45+ infiltrating cells and MUC-5AC-labeled cells.

RESULTS

Travoprost/timolol PQ was better tolerated than travoprost/timolol BAK or latanoprost/timolol BAK. This improved tolerance was evident via clinical observation under slit lamp, IVCM in different layers of the cornea and conjunctiva, conjunctival impression cytology of superficial epithelium aspects, and immunohistochemistry for inflammatory infiltration of CD45+ cells in the cornea and goblet cell distribution. Travoprost/timolol PQ was similar to PBS in regards to in-vivo findings, the Draize test for ocular irritation, and epithelial and limbal aspects as evaluated with IVCM. Treatment with either travoprost/timolol PQ or PBS produced no obvious inflammatory infiltration inside and outside the CALT follicles, yielded similar IVCM toxicity scores and CD45+ cell counts, and eyes treated with either solution had normal goblet cells.

CONCLUSION

The fixed combination of travoprost/timolol with 0.001% PQ had decreased ocular surface toxicity relative to the BAK-containing solutions. The potential benefit to the human ocular surface with oncedaily dosing needs to be evaluated clinically.

In vitro comparative toxicology of polyquad-preserved and benzalkonium chloride-preserved travoprost/timolol fixed combination and latanoprost/timolol fixed combination

PURPOSE

To compare, in vitro, the cytotoxicity profile of a new formulation of travoprost 0.004%/timolol 0.5% fixed combination ophthalmic solution preserved with polyquaternium-1 0.001% (travoprost/timolol PQ) instead of benzalkonium chloride (BAK) with (1) commercially available travoprost 0.004%/timolol 0.5% fixed combination ophthalmic solution (travoprost/timolol BAK), (2) commercially available latanoprost 0.005%/timolol 0.5% fixed combination ophthalmic solution (latanoprost/timolol BAK), and (3) their associated BAK concentrations.

METHODS

Compounds tested on Wong-Kilbourne-derived human conjunctival epithelial cells: (1) phosphate-buffered saline, (2) polyquaternium-1 0.001% (Polyquad(®), PQ), (3) travoprost/timolol PQ, (4) travoprost/timolol BAK with 0.015% BAK (DuoTrav(®)), (5) BAK 0.015%, (6) latanoprost/timolol BAK with 0.020% BAK (Xalacom(®)), and (7) BAK 0.020%. Toxicological assays were used to assess cell viability [neutral red (NR), Alamar blue (AB)], apoptosis (YO-PRO-1, Hoechst 33342), and oxidative stress (H(2)DCF-DA, hydroethidine). The apoptosis and oxidative stress assays were each reported according to cell viability as observed with NR and AB (totaling 10 analyses per treatment).

RESULTS

The NR and AB assays demonstrated that cells incubated with travoprost/timolol PQ had significantly better viability than cells incubated with latanoprost/timolol BAK, travoprost/timolol BAK, BAK 0.015%, and BAK 0.020% (P<0.0001 for all). As assessed with YO-PRO-1 and Hoechst 33342 relative to cell viability determined with NR or AB, travoprost/timolol PQ produced significantly less apoptosis than travoprost/timolol BAK and latanoprost/timolol BAK and their respective BAK concentrations alone (P<0.0001 for all). Also, travoprost/timolol BAK induced less apoptosis than latanoprost/timolol BAK (P<0.0001). As assessed with H(2)DCF-DA as a ratio to NR or AB, all of the compounds without BAK (phosphate-buffered saline, PQ 0.001%, and travoprost/timolol PQ) and travoprost/timolol BAK produced significantly less reactive oxygen species than latanoprost/timolol BAK (P<0.0001 for all). As assessed with hydroethidine as a ratio to NR or AB, travoprost/timolol PQ produced significantly fewer superoxide anions than latanoprost/timolol BAK (P<0.0001). In contrast, release of superoxide anions (hydroethidine method) after incubation with travoprost/timolol BAK was not significantly different from incubation with latanoprost/timolol BAK or travoprost/timolol PQ.

CONCLUSION

Travoprost/timolol PQ may be better for ocular surface health than either BAK preserved formulations of latanoprost/timolol or travoprost/timolol.