Enhanced disruption of the blood-aqueous barrier and the incidence of angiographic cystoid macular edema by topical timolol and its preservative in early postoperative pseudophakia

The Blood-ocular Barriers and their Dysfunction: Anatomy, Physiology, Pathology

Complex barriers comprise the blood-aqueous (BAB) and the blood-retinal barrier (BRB), and separate anterior and posterior eye chambers, vitreous body, and sensory retina from the circulation. They prevent pathogens and toxins from entering the eye, control movement of fluid, proteins, and metabolites, and contribute to the maintenance of the ocular immune status. Morphological correlates of blood-ocular barriers are tight junctions between neighboring endothelial and epithelial cells, which function as gatekeepers of the paracellular transport of molecules, thereby limiting their uncontrolled access to ocular chambers and tissues. The BAB is composed of tight junctions between endothelial cells of the iris vasculature, endothelial cells of Schlemm's canal inner wall, and cells of the nonpigmented ciliary epithelium. The BRB consists of tight junctions between endothelial cells of the retinal vessels (inner BRB) and epithelial cells of the retinal pigment epithelium (outer BRB). These junctional complexes respond rapidly to pathophysiological changes, thus enabling vascular leakage of blood-derived molecules and inflammatory cells into ocular tissues and chambers. Blood-ocular barrier function, which can be clinically measured by laser flare photometry or fluorophotometry, is compromised in traumatic, inflammatory, or infectious processes, but also frequently contributes to the pathophysiology of chronic diseases of the anterior eye segment and the retina, as exemplified by diabetic retinopathy and age-related macular degeneration.

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.

Cystoid macular edema related to cataract surgery and topical prostaglandin analogs: Mechanism, diagnosis, and management

Cystoid macular edema (CME) is a form of macular retina thickening that is characterized by the appearance of cystic fluid-filled intraretinal spaces. It has classically been diagnosed upon investigation after a decrease in visual acuity; however, improvements in imaging technology make it possible to noninvasively detect CME even before a clinically significant decrease in central vision. Risk factors for the development of CME include diabetic retinopathy, retinal vein occlusion, uveitis, and cataract surgery. It has been proposed that eyes with elevated intraocular pressure after cataract surgery, including those treated with prostaglandin analog eye drops, may be at higher risk for the development of CME. We summarize the current knowledge of the molecular mechanisms underlying CME, the potential role of ocular surgery and topical glaucoma medication in increasing the risk of CME, the newly developed imaging methods for diagnosing CME, and the clinical management of CME.

[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.

Association of Postoperative Topical Prostaglandin Analog or Beta-Blocker Use and Incidence of Pseudophakic Cystoid Macular Edema

PURPOSE

The purpose of this article is to determine the association of postoperative topical prostaglandin analog (PGA) or topical beta-blocker use and the incidence of pseudophakic cystoid macular edema (CME).

METHODS

This was a nested case-control study. All adult patients who underwent cataract surgery between January 1, 2006 and December 31, 2016 and who were enrolled in the PharMetrics Plus database were eligible for inclusion. The association between postoperative topical PGAs (bimatoprost, latanoprost, and travoprost/travoprost-z) or beta-blocker (betaxolol, levobunolol, and timolol) use and the incidence of pseudophakic CME was assessed by conditional logistic regression.

RESULTS

Five hundred eight cases and 5080 controls were included in the analyses. Incidence of pseudophakic CME was found to be statistically significantly associated with the current postoperative use of both topical PGAs [relative risk (RR), 1.86; 95% confidence interval (CI), 1.04-3.32] and topical beta-blockers (RR, 2.64; 95% CI, 1.08-6.49). Postoperative use of each of bimatoprost (RR, 2.73; 95% CI, 1.35%-5.53%) and travoprost/travoprost-z (RR, 3.16; 95% CI, 1.42-7.03) in the year before diagnosis was demonstrated to be statistically significantly associated with the incidence of pseudophakic CME. This association was not observed to be statistically significant with the postoperative use of latanoprost (RR, 1.55; 95% CI, 0.84-2.88).

CONCLUSIONS

To the best of our knowledge this is the largest study that has investigated the association between postoperative topical PGA or topical beta-blocker use and the incidence of pseudophakic CME. Postoperative use of both topical PGAs and topical beta-blockers was found to be associated with the incidence of pseudophakic CME.

BKC and CME: Is benzalkonium chloride hindering our efforts to achieve the desired postoperative visual acuity?

PURPOSE

To evaluate and compare the change in postoperative central macular thickness in patients receiving benzalkonium chloride (BKC)-preserved and BKC-free medications after uneventful phacoemulsification.

SETTING

V.M.M.C & Safdarjung Hospital, New Delhi (a tertiary health care hospital).

STUDY DESIGN

Prospective randomized comparative observational study.

MATERIALS AND METHODS

Once patients were selected, the baseline standard ophthalmic examination was done.

SAMPLE SIZE

140 eyes were enrolled and randomly divided into two groups. (a) Group I: receive BKC-preserved topical medications and (b) Group II: receive BKC-free topical medications of same constituents postoperatively. Group I patients received topical BKC-preserved moxifloxacin 0.5% + dexamethasone 0.1% eye drops six times a day, timolol maleate 0.5% twice daily, tropicamide 0.8% + phenylephrine 5% once a day for 6 weeks, and Group II received same BKC-free topical eye drops for 6 weeks. Postoperatively, the patients were reviewed at day 1, week 1, week 6 for same parameters.

STATISTICS

Quantitative variables: paired and unpaired t test. p value < 0.05 was considered statistically significant.

RESULTS

The mean CMT in μm at 1 week in Group I was 269.39 ± 14.56 and in Group II was 270.04 ± 6.56. The mean CMT in µm at 6 weeks in Group I was 270.39 ± 17.18 and in Group II was 270.90 ± 7.00.

CONCLUSION

Neither do BKC-preserved topical medications have any independent role in increasing the central macular thickness after uneventful surgery nor do they have any role in causing pseudophakic CME.

Switch from BAK-preserved to preservative-free latanoprost decreases anterior chamber flare in POAG patients

PURPOSE

To validate the hypothesis that BAK induces low-grade inflammation in the anterior chamber, we designed a study to investigate whether switching from BAK-preserved to preservative-free latanoprost in patients with primary open-angle glaucoma (POAG) would reduce the flare levels.

PATIENTS

Forty-one eyes of twenty-two patients with primary open-angle glaucoma treated with BAK-preserved latanoprost for at least 6 months as monotherapy were included. Exclusion criteria included any use of topical eye drops other than latanoprost, pseudoexfoliation and pigment dispersion glaucoma, wearing of contact lenses and intraocular surgery in the past year.

METHODS

At the start of the study, we measured baseline flare values. We then switched all patients to preservative-free latanoprost. After 1, 2, and 3 months, a routine ophthalmological examination was performed and flare measurement repeated.

RESULTS

Thirty-three eyes were followed up throughout the entire 3-month period. One month after the switch to preservative-free latanoprost, a statistically significant mean drop in flare of - 0.96 ph/ms (P = 0.025) was observed. Mean flare decreased further by - 1.31 ph/ms (P = 0.0027) after 2 months and by - 1.25 ph/ms (P = 0.0041) after 3 months.

CONCLUSION

The switch from BAK-preserved to preservative-free latanoprost induced a statistically significant reduction in mean flare value. Whereas our previous study showed an increase in flare when initiating treatment with BAK-preserved eye drops, this study shows a decrease in flare upon cessation of BAK-preserved drugs. The combined evidence from the two studies strongly suggests that in humans BAK exerts its effects not only on the ocular surface, but also at the level of the anterior chamber.

The Effect of Latanaprost on Intraocular Inflammation and Macular Edema

There is debate concerning whether the use of Latanoprost in early postoperative period of cataract surgery and in glaucoma patients with uveitis as it may aggravate the inflammation and results in macular edema (ME), because of blood-ocular barrier disruption. However, there is no solid evidence for disruption of blood-ocular barrier with Latanoprost and aggravation of uveitis or ME formation. Similar to pseudophakic ME, the imaging ME in cases claimed to be secondary to Latanoprost is greater than clinical ME, happens mostly in complicated surgeries, and the vast majority resolve within weeks to months with using a non-steroidal anti-inflammatory drug. The current literature suggests that Latanoprost can be used in patients with uveitis and early after cataract surgery with or without concomitant topical non-steroidal anti-inflammatory drugs that are currently used by many ophthalmologists as a preventive measure for ME even in non-glaucoma uncomplicated cataract surgeries.

Pseudophakic Macular Edema in Primary Open-Angle Glaucoma: A Prospective Study Using Spectral-Domain Optical Coherence Tomography

PURPOSE

To determine the incidence of and risk factors for pseudophakic macular edema (PME) after uncomplicated cataract surgery in primary open-angle glaucoma (POAG) using spectral-domain optical coherence tomography (SDOCT).

DESIGN

Cohort study.

METHODS

Macular retinal thickness was evaluated using SDOCT at 1 week before surgery and at 1, 3, 6, and 12 months postoperatively, in 70 POAG and 68 control eyes. Forty-three healthy subjects without impaired vision or cystoid PME were recruited separately as pilot samples to define significant PME. Significant PME was defined as an increase in the average thickness exceeding the mean + 3 standard deviations of the increase shown in the pilot samples.

RESULTS

Significant PME (increase in the foveal 3-mm zone thickness of >19.5 μm) was observed in 31 (44%) eyes with POAG and in 14 (21%) control eyes (P = .003). The extent of PME was maximal at 3 months postoperatively and decreased gradually until 12 months. Regression tree analysis revealed that the risk of PME was the greatest in the POAG group using prostaglandin analogue (PGA) (odds ratio [OR] = 5.51), followed by POAG not using PGA (OR = 1.70), and control group (OR = 1.0). Risk factors for PME were younger age in all groups (OR = 1.07), systemic hypertension in PGA users (OR = 6.42), higher untreated IOP in PGA nonusers (OR = 1.09) and male sex (OR = 14.06) and diabetes mellitus (OR = 16.71) in the control group.

CONCLUSIONS

The incidence of PME as observed by SDOCT was higher than previously reported after uncomplicated cataract surgery. Eyes with POAG were at greater risk for PME, which was mainly associated with perioperative PGA use.

Bimatoprost (0.03%)-induced accommodative spasm and pseudomyopia

Bimatoprost is a prostaglandin analogue used topically in the treatment of glaucoma. Commonly known side effects include eyelash growth, iris pigmentation and conjunctival hyperemia. While pseudomyopia is reported to be caused by parasympathomimetics, such an effect precipitated by bimatoprost has not yet been reported. We report a case demonstrating pseudomyopia and accommodative spasm caused after starting bimatoprost 0.03% in a young patient with glaucoma.

Prevention of Cystoid Macular Edema After Cataract Surgery in Nondiabetic and Diabetic Patients: A Systematic Review and Meta-Analysis

PURPOSE

To evaluate the optimum medical strategy to prevent cystoid macular edema (CME) after cataract surgery.

DESIGN

Systematic review and meta-analysis.

METHODS

setting: Cochrane, MEDLINE, and EMBASE databases were searched to identify eligible randomized controlled trials (RCTs).

STUDY POPULATION

RCTs comparing medical strategies to prevent CME after uncomplicated cataract surgery in nondiabetic and diabetic patients.

OBSERVATION PROCEDURES

Data were extracted by 2 authors independently. Quality of individual RCTs was assessed using the Cochrane Collaboration's tool for assessing risk of bias and Delphi criteria.

MAIN OUTCOME MEASURES

Odds of developing CME within 3 months postoperatively and foveal thickness, macular volume and corrected distance visual acuity change within 3 months postoperatively, as compared to baseline.

RESULTS

Seventeen trials reported incidence rates. Topical nonsteroidal anti-inflammatory drugs (NSAIDs) significantly reduced the odds of developing CME as compared to topical corticosteroids in nondiabetic (odds ratio [OR] 0.11; 95% confidence interval [95% CI] 0.03-0.37) and mixed populations (OR 0.05; 95% CI 0.02-0.11). A combination of topical corticosteroids and NSAIDs significantly reduced the odds of developing CME as compared to topical corticosteroids in nondiabetic (OR 0.21; 95% CI 0.10-0.44) and diabetic patients (OR 0.17; 95% CI 0.05-0.50). Intravitreal corticosteroid or anti-vascular endothelial growth factor injections did not show any additional benefit in diabetic subjects.

CONCLUSIONS

Topical NSAIDs significantly reduced the odds of developing CME, as compared to topical corticosteroids, in nondiabetic and mixed populations. A combination of topical NSAIDs and corticosteroids reduced the odds of developing CME in nondiabetic and diabetic patients, as compared to topical corticosteroids.

Managing adverse effects of glaucoma medications

Glaucoma is a chronic, progressive disease in which retinal ganglion cells disappear and subsequent, gradual reductions in the visual field ensues. Glaucoma eye drops have hypotensive effects and like all other medications are associated with adverse effects. Adverse reactions may either result from the main agent or from preservatives used in the drug vehicle. The preservative benzalkonium chloride, is one such compound that causes frequent adverse reactions such as superficial punctate keratitis, corneal erosion, conjunctival allergy, and conjunctival injection. Adverse reactions related to main hypotensive agents have been divided into those affecting the eye and those affecting the entire body. In particular, β-blockers frequently cause systematic adverse reactions, including bradycardia, decrease in blood pressure, irregular pulse and asthma attacks. Prostaglandin analogs have distinctive local adverse reactions, including eyelash bristling/lengthening, eyelid pigmentation, iris pigmentation, and upper eyelid deepening. No systemic adverse reactions have been linked to prostaglandin analog eye drop usage. These adverse reactions may be minimized when they are detected early and prevented by reducing the number of different eye drops used (via fixed combination eye drops), reducing the number of times eye drops are administered, using benzalkonium chloride-free eye drops, using lower concentration eye drops, and providing proper drop instillation training. Additionally, a one-time topical medication can be given to patients to allow observation of any adverse reactions, thereafter the preparation of a topical medication with the fewest known adverse reactions can be prescribed. This does require precise patient monitoring and inquiries about patient symptoms following medication use.

In vitro methods of assessing ocular biocompatibility using THP-1-derived macrophages

Macrophages play an important role in the elimination of infections, the removal of debris and in tissue repair after infection and trauma. In vitro models that assess ocular biomaterials for toxicity typically focus on the effects of these materials on epithelial or fibroblast cells. This investigation evaluated known ocular toxins deposited on model materials for their effects on the viability and activation of macrophages. THP-1-derived macrophages were cultured onto silicone films (used as a base biomaterial) deposited with chemical toxins (benzalkonium chloride (BAK), zinc diethyldithiocarbamate (ZDEC) and lipopolysaccharide (LPS)). Utilizing three fluorescent dyes calcein, ethidium homodimer-1 (EthD-1) and annexin V, the viability of macrophages attached to the biomaterial was determined using confocal microscopy. Propidium iodide (PI) staining and alamarBlue® (resazurin) reduction were used to assess cell death and metabolic activity. CD14, CD16, CD33, CD45, and CD54 expression of adherent macrophages, were also evaluated to detect LPS activation of macrophages using flow cytometry. The sensitivity of this test battery was demonstrated as significant toxicity from treated surfaces with ZDEC (0.001-0.01%), and BAK (0.001%-0.1%) was detected. Also, macrophage activation could be detected by measuring CD54 expression after exposure to adsorbed LPS. These in vitro methods will be helpful in determining the toxicity potential of new ocular biomaterials.

Effects of benzalkonium chloride on the blood-aqueous and blood-retinal barriers of pseudophakic eyes

PURPOSE

To evaluate the effects of benzalkonium chloride (BAK) on the blood-aqueous (BAB) and blood-retinal barriers (BRB) of pseudophakic eyes.

METHODS

Prospective, randomized, investigator-masked, comparative study. Patients were randomly assigned to preservative-free artificial tears or BAK-preserved artificial tears. One drop of artificial tears was instilled 4 times a day in the study eye, starting the day after randomization for 30 days. Anterior chamber flare was assessed by a laser flare meter (LFM) and macular thickness measurements were obtained with optical coherence tomography, before, 15, and 30 days after randomization.

RESULTS

A total of 44 healthy eyes of 44 pseudophakic volunteers were recruited. There were no significant differences regarding demographics (age, gender, and race distributions) and clinical characteristics (eye, mean intraocular pressure, and mean best-corrected visual acuity) between the 2 groups (P>0.05). No significant differences in baseline mean LFM values were observed (P=0.262). However, we detected a statistically significant increase in mean LFM measurements in the BAK-preserved group (11.4 ± 5.1 ph/ms) (P=0.017) after 15 days. After 30 days, the BAK-preserved group maintained significantly higher flare values (11.9 ± 5.9 ph/ms) compared with baseline (P=0.043). On the other hand, the preservative-free group showed mean flare values of 8.4 ± 2.5 ph/ms, not significantly different from those obtained at baseline (P=1.00). We observed no statistically significant change in macular thickness measurements at days 15 and 30 in either group (P>0.05). Cystoid macular edema was not detected in this series.

CONCLUSIONS

Our results suggest that a short-term exposure to BAK can cause disruption of the BAB, without altering the BRB in pseudophakic eyes.

Subtenon triamcinolone injection for postoperative cystoid macular edema associated with tafluprost

PURPOSE

We report the successful treatment of a case of cystoid macular edema (CME) associated with topical tafluprost, which was accompanied by serous retinal detachment (SRD).

CASE

A 78-year-old woman underwent intraocular lens suture surgery, including anterior vitreous cutting, for crystalline lens dislocation in the right eye. Tafluprost was initiated 12 weeks after surgery. Intraocular pressure (IOP) was controlled at 10-14 mmHg. Visual acuity remained at 20/40-30/40. However, the patient complained of blurred vision (20/200) 9 months after surgery. CME accompanied by SRD was identified by optical coherence tomography (OCT) and treated with subtenon triamcinolone injection. Visual acuity rapidly increased to 20/50, and the volume of SRD decreased in a few days. Discontinuation of tafluprost and initiation of diclofenac eye drops improved visual acuity to 20/40 and resulted in improved OCT findings within a few weeks. Three months after injection, tafluprost was resumed along with diclofenac. No recurrence of CME occurred over the following 3 months, and IOP was controlled at 10-15 mmHg.

CONCLUSION

SRD is considered to be a symptom of treatment-resistant CME, which may lead to poor visual acuity after recovery. In such cases, subtenon triamcinolone injection should be strongly considered at an early stage.

Successful treatment of prostaglandin-induced cystoid macular edema with subtenon triamcinolone

Purpose

Cystoid macular edema (CME) is associated with the use of prostaglandin eye drops after cataract surgery. The study aim was to report on the treatment of two CME patients with subtenon triamcinolone injections.

Methods

Case one was a 70-year-old woman who underwent uneventful cataract surgery. Travoprost was administrated at 10 weeks after surgery, and CME occurred at 13 weeks after surgery. Case two was an 85-year-old man who underwent intraocular lens extraction and an intraocular lens suture operation. Latanoprost was readministered after the surgery. The patient complained of blurred vision 3 years later.

Results

For both cases, discontinuation of the prostaglandin eye drops, subsequent initiation of treatment with diclofenac eye drops, and subtenon injection of triamcinolone was followed by the rapid disappearance of the CME. After the CME had disappeared for 3 months, the prostaglandin eye drops were resumed. Diclofenac was added in case two. No CME recurrence was seen in either case over 2 years.

Conclusion

Subtenon triamcinolone injection can be effective for CME associated with prostaglandin eye liquid after cataract surgery. Prostaglandin eye liquid that causes CME is not necessarily precluded for future use if administered under careful observation.

Controversy: Is Benzalkonium Chloride Necessary in Antiglaucoma Drops?

Medical therapy is the first-line option in glaucoma management, with benzalkonium chloride (BAC) being the most frequently used preservative in antiglaucoma medications. Its use is however, known to be associated with deleterious effects on the ocular surface. This review is an attempt to critically evaluate whether BAC really is indispensable for better bioavailability of antiglaucoma drugs and consequently, better IOP control.

How to cite this article: Louati Y, Shaarawy T. Controversy: Is Benzalkonium Chloride Necessary in Antiglaucoma Drops? J Current Glau Prac 2012;6(3):104-107.

Benzalkonium chloride induces anterior chamber inflammation in previously untreated patients with ocular hypertension as measured by flare meter: a randomized clinical trial

PURPOSE

The deleterious effects of benzalkonium chloride (BAK) on the ocular surface are well known. However, few clinical data are available to prove a toxic effect at the level of the anterior chamber. The laser flare meter is a reliable tool to detect low levels of inflammation in the anterior chamber. We wanted to know whether instillation of BAK-preserved timolol in one eye would result in higher laser flare values than the instillation of preservative-free timolol in the fellow eye.

METHODS

Randomized prospective, single-masked clinical trial. Twenty-eight untreated patients with ocular hypertension were recruited. After obtaining baseline flare values, we randomly assigned one eye to BAK-preserved timolol and the fellow eye to preservative-free timolol. After 1 month, flare measurements were repeated.

RESULTS

There was a significant increase in the flare values in the two treatment regimens, but the increase in the BAK-treated eyes was higher than in the preservative-free treated eyes, and this difference in increase was statistically significant.

CONCLUSION

This is the first study to show that short-term BAK administration produces inflammation in the anterior segment of previously untreated patients whose blood-aqueous barrier was not affected by recent intraocular surgery.

Handling test of eye drop dispenser--comparison of unit-dose pipettes with conventional eye drop bottles

PURPOSE

The aims of this study were to investigate how elderly people handle single-use eye drop dispensers (unit-dose pipettes) and to compare the performance with conventional eye drop bottles.

METHODS

In this open-label study, the handling of unit-dose pipettes and conventional eye drop bottles was compared in 41 elderly people who had little or no prior regular use of eye drop dispensers. The participants tested both types of dispenser once, and the following 7 variables were studied: ease/difficulty of opening the dispenser; influence of the size for handling of the dispenser; influence of the shape for handling of the dispenser; observation of the contents in the dispenser; the feeling of the dispenser in the hand; ease/difficulty of drop instillation on the eye from the dispenser; and overall performance of the eye drop dispenser. The dispensers contained isotonic saline, and a visual analog scale was used for assessment of each of the above variables.

RESULTS

The mean age of the participants was 73 years. A statistically significant difference in favor of the unit-dose pipettes was found with respect to observation of the contents in the dispenser, ease of administration, and the overall performance. Women regarded the unit-dose pipettes generally better than the bottles, but such a difference was not seen in men.

CONCLUSIONS

The study participants managed the unit-dose pipettes at least as well as the conventional eye drop bottles. If anything, the unit-dose pipettes appeared to be easier to use.

Clinical cystoid macular edema after cataract surgery in glaucoma patients

PURPOSE

To determine the prevalence of and risk factors for developing clinical cystoid macular edema (CME) after cataract surgery in patients with glaucoma.

PATIENTS AND METHODS

Medical records of patients who had cataract surgery between April 1998 and July 2006 without prior history of CME, a known risk factor to develop CME, or previous nonglaucoma ocular laser procedures or intraocular surgeries were reviewed. Clinical CME was diagnosed by fundus examination within 3 months postoperatively and confirmed with fluorescein angiography or optical coherence tomography. Outcome measures included prevalence of clinical CME by comparing patients with and without glaucoma; and risk factor analysis for clinical CME by comparing patients who did and did not develop CME after cataract surgery.

RESULTS

Seven hundred patients (eyes) with glaucoma and 553 patients (eyes) without glaucoma were included. The prevalences of clinical CME in glaucoma and nonglaucoma patients were 5.14% and 5.79%, respectively (P=0.618). Patients who developed clinical CME (68 patients) had statistically higher rates of posterior capsule rupture or required anterior vitrectomy during surgery (P=0.010, odds ratio=3.35, 95% CI 1.33-8.45) compared with patients who did not develop clinical CME (1185 patients). No glaucoma medications used either preoperatively or postoperatively were associated with clinical CME (P>0.05).

CONCLUSIONS

Rupture of posterior capsule and anterior vitrectomy during cataract surgery is a potential risk factor for developing clinical CME after cataract surgery. There is no statistically significant difference in the prevalence of clinical CME after small corneal incision phacoemulsification cataract surgery between glaucoma and nonglaucoma patients.

Rat model for anterior segment intraocular surgery induced blood-retinal barrier breakdown

PURPOSE

To develop a practical rat model of blood-retinal barrier (BRB) breakdown induced by anterior segment intraocular surgery.

METHODS

A 27-gauge needle attached to infusion tubing running to a bottle of balanced salt solution was inserted through the limbus into the rat anterior chamber. The pressure of the balanced salt solution was oscillated from 0 to 12 mm Hg above the atmospheric pressure for 30 times. The needle was removed and the anterior chamber was formed. Then the eye was exposed vertically to the light of the operating microscope. The contralateral eye was left untreated. The eyes were applied with ofloxacin ophthalmic solution after surgery. At several time points after surgery, the integrity of the BRB was assessed by fluorescence fundus angiography, optical coherence tomography, immunohistochemical staining for serum albumin and quantitative measurement using Evans blue as a tracer.

RESULTS

The extravasation of fluorescein, the increased central retinal thickness, strong staining for albumin in the retina and substantially elevated retinal Evans blue leakage demonstrated BRB breakdown after anterior segment intraocular surgery. On the 1st day after surgery, the model group showed a statistically significant elevation in the retinal Evans blue leakage as compared to the contralateral control group and the normal control group. These increased and reached the peak on the 2nd day after surgery and decreased to the point that there was no significant difference as compared to the contralateral control group and the normal control group on the 7th day after surgery.

CONCLUSIONS

This study establishes a practical rat model of BRB breakdown induced by anterior segment intraocular surgery.

Clinical pseudophakic cystoid macular edema

PURPOSE

To characterize the incidence, duration, and risk factors for and outcome of cystoid macular edema (CME) after cataract surgery and investigate the effects of treatment regimens on visual outcome and duration.

SETTING

University-based comprehensive ophthalmology practice.

METHODS

This study included 1659 consecutive cataract surgeries performed by residents between 2001 and 2006. Cases were classified according to the presence of CME. Subset analysis excluded patients with diabetes mellitus (DM). The CME groups were analyzed according to type of treatment to compare duration of CME and final best corrected visual acuity.

RESULTS

The incidence of postoperative CME was 2.35% (39/1659), and history of retinal vein occlusion (RVO) was predictive of postoperative CME (odds ratio [OR], 47.12; P<.001). When patients with DM were excluded, the incidence of CME was 2.14% (29/1357) and history of RVO (OR, 31.75; P<.001), epiretinal membrane (ERM) (OR, 4.93; P<.03), and preoperative prostaglandin use (OR, 12.45; P<.04) were predictive of postoperative CME. Patients with DM and/or intraoperative complications did not have an increased risk for CME when treated with prophylactic postoperative nonsteroidal antiinflammatory drugs (NSAIDs) for 3 months. Groups treated with NSAIDs plus a steroid had significantly shorter resolution times than the untreated group (P = .004).

CONCLUSIONS

A history of RVO, ERM, and preoperative prostaglandin use were associated with an increased risk for pseudophakic CME. Treatment with NSAIDs plus steroids was associated with faster resolution of CME than no treatment. Treating high-risk patients with NSAIDs after cataract surgery decreases the incidence of postoperative CME to that of patients who are not at high risk.

Diclofenac prevents an early event of macular thickening after cataract surgery in patients with diabetes

PURPOSE

This study compares the effect of topical diclofenac with that of betamethasone against postoperative cystoid macular edema (CME) following cataract surgery in patients with non- and mild nonproliferative diabetic retinopathy.

METHODS

Forty-six (46) consecutive patients with mild nonproliferative- or nondiabetic retinopathy who had bilateral and symmetrical cataracts underwent uncomplicated cataract surgery in both eyes (92 eyes in total). Postoperatively, topical diclofenac was applied 4 times daily for 1 eye, and topical betamethasone 4 times daily for the other eye in each patient. Best corrected logMAR visual acuity (BCVA), averaged foveal thickness (FT) as measured by optical coherence tomography (OCT), and intraocular pressure (IOP) were monitored preoperatively, and also postoperatively at 1 day and 1, 4, and 8 weeks.

RESULTS

VA in both the diclofenac- and betamethasone-treated eyes significantly improved following the cataract surgery; however, no statistical difference of VA was noted between the diclofenac- and betamethasone-treated eyes throughout the observational period (before and after the surgery until 8 weeks postoperatively). FT in both eyes increased after the cataract surgery. FT in the diclofenac-treated eyes did not increase 1 week after surgery, but gradually increased at week 4 and week 8. In contrast, the FT in the betamethasone-treated eyes increased during 1-8 weeks postoperatively. IOP in the diclofenac-treated eyes decreased with time, but IOP in the betamethasone-treated eyes showed no change throughout the observational period.

CONCLUSIONS

Postoperative macular thickening following cataract surgery in patients with non- or mild nonproliferative-diabetic retinopathy cannot be fully suppressed by either topical diclofenac or betamethasone. Nonetheless, diclofenac protected against an early event of postoperative CME and also a decrease of IOP.

[Treatment of pseudophakic cystoid macular edema]

Pseudophakic cystoid macular edema (PCME) is the most common complication following cataract surgery. In 1-3% of cases it is associated with a decrease in visual acuity. However, PCME has a good prognosis, persisting in only 10% of the patients beyond 2 years. The prophylactic therapy of eyes without additional disease with non-steroidal antiphlogistic drugs or steroids does not influence the final visual acuity. Under certain circumstances, prophylaxis can be a reasonable option. Risk factors that promote the formation of PCME are discussed. The course of acute or chronic PCME can be influenced by drug treatment, but in general the level of evidence for the treatment of this widespread problem is low. We would therefore like to present the Freiburg treatment scheme for PCME for discussion.

The effect of ocular hypotensive agents on macula

We evaluated the effect of long-term topical antiglaucoma drugs on the macula using the noninvasive macular visual field threshold test in 100 eyes of 75 patients with ocular hypertension or primary open-angle glaucoma. We found that topical antiglaucoma agents can alter macular sensitivity after long-term therapy and advise evaluation of the macula in glaucoma patients receiving antiglaucomatous agents.

Effect of ophthalmic solution components on acrylic intraocular lenses

PURPOSE

To investigate the effect of ophthalmic solution components on the surface of acrylic intraocular lenses (IOLs).

SETTING

Department of Opthalmology, Showa University School of Medicine.

METHODS

Measurement of the contact angles of ophthalmic solutions on 3 acrylic IOLs was performed. The solutions were diclofenac sodium (Diclod), bromfenac sodium (Bronuck), betamethasone phosphate (Rinderon), dibekacin sulfate (Panimycin), polysorbate 80 (Tween 20), benzalkonium chloride, chlorobutanol, methylparahydroxybenzoate, and propylparahydroxybenzoate. The IOLs were incubated at 35 degrees C for 2 weeks in undiluted ophthalmic solutions and in 1:10 dilutions of ophthalmic solution components. The IOLs were sectioned and observed by scanning electron microscopy.

RESULTS

The contact angle of Diclod and Bronuck solutions was the smallest. The contact angle of Rinderon and Panimycin was similar to that of distilled water. Scanning electron microscopy examination of IOLs incubated in ophthalmic solution components showed intralenticular changes. The IOLs immersed in ophthalmic solutions did not show any change, even after extended incubation.

CONCLUSION

The chemical components of ophthalmic solutions, such as surfactants and solvents, permeate acrylic IOLs, suggesting the potential for long-term adverse effects of eyedrops in pseudophakic eyes.

The effects of prostaglandin analogues on the blood aqueous barrier and corneal thickness of phakic patients with primary open-angle glaucoma and ocular hypertension

PURPOSE

To evaluate the effects of topical latanoprost, travoprost, and bimatoprost on the blood-aqueous barrier and central corneal thickness (CCT) of patients with primary open-angle glaucoma (POAG) and ocular hypertension (OHT).

DESIGN

Prospective, randomized, masked-observer, crossover clinical trial.

METHODS

A total of 34 phakic patients with POAG or OHT with no previous history of intraocular surgery or uveitis completed the study. Patients were randomized to use latanoprost 0.005%, travoprost 0.004%, or bimatoprost 0.03% once daily (2000 hours) for 1 month, followed by a washout period of 4 weeks between each drug. Aqueous flare was measured with a laser flare metre. CCT was calculated as the average of five measurements using ultrasound pachymetry. All measurements were performed by a masked observer (1000 h).

RESULTS

There were no statistically significant differences between baseline mean IOP, mean CCT, and mean flare values among the groups. There was no statistically significant increase in mean flare values from baseline in all groups (P>0.05). There were no statistically significant differences between mean flare values among the groups (P>0.05). All medications significantly reduced the mean IOP from baseline (P<0.0001). IOP reduction obtained with travoprost (7.3+/-3.8 mmHg) was significantly higher than that obtained with latanoprost (4.7+/-4.2 mmHg) (P=0.01). A statistically significant reduction in mean CCT (0.6+/-1.3%) from baseline was observed when patients instilled bimatoprost (P=0.01).

CONCLUSIONS

Latanoprost, travoprost, and bimatoprost had no statistically significant effect on the blood-aqueous barrier of phakic patients with POAG or OHT. Bimatoprost may be associated with a clinically irrelevant reduction in mean CCT.

Prospective randomized controlled trial of the effect of intracameral vancomycin and gentamicin on macular retinal thickness and visual function following cataract surgery

PURPOSE

To investigate whether the use of vancomycin (20 microg/mL) and gentamicin (8 microg/mL) in the infusion fluid at the time of cataract surgery increases the incidence of macular thickening as measured with optical coherence tomography (OCT) following phacoemulsification.

SETTING

A public teaching hospital in Western Australia.

METHODS

Fourty-one patients (50 eyes) with cataracts between 50 and 85 years of age were randomized to receive no antibiotics in the infusion fluid at the time of cataract surgery (control group) or vancomycin (20 microg/mL) and gentamicin (8 microg/mL) in the infusion fluid (antibiotic group). Optical coherence tomography measurements were performed preoperatively and 1 day and 1 and 5 weeks postoperatively. A significant increase in macular thickness (mean of the central 1.0 mm diameter) on OCT was defined as 15 microm or greater. Five weeks postoperatively, the best corrected Snellen acuity and Pelli-Robson contrast sensitivity were measured.

RESULTS

Twenty-five percent in the control group and 38% in the antibiotic group had a significant increase in macular thickness measured on OCT 5 weeks postoperatively (P = .34). The mean contrast sensitivity of patients with increased macular thickness on OCT was 1.26, and in those with no change it was 1.43 (P = .001).

CONCLUSIONS

The use of intracameral vancomycin (20 microg/mL) and gentamicin (8 microg/mL) at the time of cataract surgery had no significant effect on macular thickness or visual function postoperatively. Overall, 31% of eyes showed an increase of 15 microm or greater in central retinal thickness. These patients had significantly reduced contrast sensitivity.

Therapeutic Strategies for Normal-Tension Glaucoma

Treatment of normal-tension glaucoma has been a subject of debate for several years. Glaucomatous damage cannot be influenced directly, and current treatment modalities in normal-tension glaucoma are aimed at the control of risk factors. Intraocular pressure is a widely accepted risk factor and its reduction can improve the prognosis in normal-tension glaucoma patients. The repeated demonstration of the importance of hemodynamic factors in normal-tension glaucoma has, however, not been paralleled by a comparable progress in the development of therapeutic modalities capable of influencing favorably ocular blood flow. Today, calcium channel blockers seem to be the most promising adjunctive treatment to be considered in patients with glaucomatous optic neuropathy without increased intraocular pressure.

A 6-month assessment of bimatoprost 0.03% vs timolol maleate 0.5%: hypotensive efficacy, macular thickness and flare in ocular-hypertensive and glaucoma patients

AIM

To compare 6 months of treatment with bimatoprost and timolol in terms of their hypotensive efficacy and secondary effects, including changes in macular thickness and the inflammatory reaction induced in the anterior chamber.

METHODS

A prospective, randomized, parallel-group trial performed on 30 eyes of 30 patients per group. The main outcome measure was the difference between the IOP value taken between the baseline visit and the 6-month-visit. Macular thickness determined through optical coherence tomography and anterior chamber inflammation estimated using the laser flare meter was also evaluated. Adverse events were recorded during the study period.

RESULTS

Bimatoprost treatment gave rise to a significantly lower mean IOP than timolol in all follow-up visits as from the first month (P<0.05). Bimatoprost achieved high percentage IOP reductions from baseline in a significantly higher proportion of patients (P<0.05). Macular thickness and anterior chamber flare failed to vary significantly both between the two groups and within each group during the 6-month evaluation (P>0.05).

CONCLUSIONS

Bimatoprost 0.03% once daily showed a greater efficacy then timolol 0.05% twice daily in patients with elevated IOP. No significant differences were detected in macular thickness or anterior uveitis using optical coherence tomography and laser flare photometry.

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.

ESCRS Binkhorst Lecture 2002: Pseudophakic preservative maculopathy

Many antiglaucoma eyedrops are reported to cause cystoid macular edema (CME) in aphakia and pseudophakia. We review 4 clinical and laboratory studies that compare the incidence of CME in early postoperative pseudophakia in eyes that received preserved latanoprost and timolol, nonpreserved timolol, and the preserved and nonpreserved vehicle for these drugs and looked at the morphological damage to cells and the changes in the indicators of cytokine and prostaglandin (PG) synthesis caused by latanoprost and timolol and the preservative benzalkonium chloride. Based on the findings of these studies, which indicate that the preservative causes increased synthesis of PGs and other substances and intensified postoperative inflammation, the term pseudophakic preservative maculopathy is proposed for CME caused by antiglaucoma eyedrops.