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

Incidence of Acute Cystoid Macular Edema After Starting a Prostaglandin Analog Compared With Other Classes of Glaucoma Medications

PURPOSE

There is a longstanding belief that prostaglandin analogs (PGAs) may predispose patients with glaucoma to develop acute cystoid macular edema (CME). However, there is little solid evidence supporting this notion. The purpose of this study is to compare CME incidence rates among patients initiating treatment with different glaucoma medication classes.

DESIGN

Database study.

PARTICIPANTS

39948 patients who were newly prescribed glaucoma medications METHODS: Using data from 10 health systems contributing data to the Sight Outcomes Research Collaborative (SOURCE) Ophthalmology Data Repository, we identified all adults with glaucoma who had been newly started on a topical glaucoma medication. Patients with pre-existing documentation of macular edema were excluded. We assessed the incidence of CME among patients with glaucoma who were newly started on PGAs, topical beta blockers (BBs), alpha agonists (AAs), and carbonic anhydrase inhibitors (CAIs). Using multivariable logistic regression, and adjusting for sociodemographic factors, we assessed the odds of developing CME among patients prescribed each of the 4 glaucoma medication classes. We also performed a subset regression analysis including lens status as a co-variate.

MAIN OUTCOME MEASURES

Incidence of CME within 3 months of initiating therapy with different topical glaucoma medications.

RESULTS

Among the 39,948 patients were newly treated with a topical glaucoma medication, 139 (0.35%) developed CME. The incidence of CME was 0.13%, 0.65%, 0.55%, 1.76% for users of PGAs, BBs, alpha agonists (AAs) and carbonic anhydrase inhibitors (CAIs), respectively. After adjusting for sociodemographic factors, users of topical BBs, AAs and CAIs had substantially higher odds of developing CME compared with PGA users (P<0.001 for all comparisons). The subset analysis also showed higher odds ratio of the non-PGA medication classes in association with CME.

CONCLUSIONS

Clinicians should reconsider the notion that PGAs carry a higher risk of CME versus other glaucoma medication classes. If additional studies support the findings of these analyses, clinicians may feel more comfortable prescribing PGAs to patients with glaucoma without fear they will predispose patients to CME.

Changes in Macular Thickness after Cataract Surgery in Patients with Open Angle Glaucoma

BACKGROUND

The purpose of this study was to examine the changes in IOP, total macular and RNFL, ganglion cell layer (GCL) thickness, and aqueous humour flare in open angle glaucoma (OAG) patients before and 6 months after cataract surgery.

METHODS

This was a prospective observational case-control age- and gender-matched study. Groups: 40 subjects in a controlled OAG (OAG_c) group, 20 subjects in an uncontrolled OAG (OAG_u) group, and 60 control group subjects.

EXAMINATION

complete ophthalmic evaluation, IOP measurement, anterior and posterior segment Optical Coherence Tomography (OCT), and laser flare photometry before and 6 months postoperatively.

RESULTS

Six months postoperatively IOP decreased in all groups. An increase in macular thickness was found postoperatively in all groups. Preoperative aqueous humour flare was higher in the OAG_c group than in the control group. After cataract surgery, aqueous humour flare was higher in the control group compared to the preoperative result.

CONCLUSIONS

Changes in IOP following cataract surgery were strongly negatively correlated with preoperative IOP. An increase in macular thickness was observed 6 months postoperatively in all groups. Aqueous humour flare did not differ in OAG_c and OAG_u groups pre- and postoperatively but significantly increased in the control group postoperatively.

The Effect of Prostaglandin Analogs on Central Corneal Thickness of Patients with Glaucoma or Ocular Hypertension: A Systematic Review

BACKGROUND

Prostaglandin analogs (PGAs) are first-line antiglaucoma agents that appear to either decrease or increase central cornea thickness (CCT), creating controversy regarding the benefits of PGAs in treating CCT.

PURPOSE

We performed the first meta-analysis of observational studies to evaluate the effects of PGAs on CCT in patients with glaucoma or ocular hypertension (OHT).

METHODS

This systematic review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statement. A literature search was performed of the PubMed, Embase, Cochrane Library, System for Information on Grey Literature in Europe (Open Grey), and ClinicalTrials.gov databases and the references of retrieved studies. Only observational studies were included in the meta-analysis. The final CCT of patients and 95% confidence interval (CI) of each study were extracted. Study quality was assessed using the Newcastle-Ottawa Scale (NOS) and the Agency for Healthcare Research and Quality (AHRQ). A fixed-effects model was used to calculate the weighted mean difference (WMD) and 95% CI. Subgroup analyses based on several stratified factors such as public bias (Begg's test) and sensitivity analyses were performed.

RESULTS

Five cohort, 5 case-control, and three cross-sectional studies including 2,722 subjects were included. The pooled effect of all thirteen studies showed that PGAs reduced the CCT of patients with glaucoma or OHT slightly but significantly (WMD = -9.37; 95% CI [-12.18, -6.57]; p = 0.00; I2 = 45.5%). Significant effects were also observed in all three study designs: cohort (WMD = -5.17; 95% CI [-9.52, -0.82]), case-control (WMD = -15.31; 95% CI [-22.66, -7.97]), and cross-sectional (WMD = -8.65; 95% CI [-17.30, -0.01]). In addition, subgroup analysis of exposure time showed the effect of PGAs to be more obvious in the first (WMD = -5.81; 95% CI [-9.49, -2.14]) and second (WMD = -13.73; 95% CI [-20.19, -7.28]) years.

CONCLUSIONS

The pooled effects of previously reported studies suggest that PGA use can reduce the CCT of patients with glaucoma or OHT slightly but significantly, with this effect more pronounced in the first 2 years. These findings suggest that clinicians must closely monitor changes in CCT in the first 2 years of PGA use to identify cases of intraocular pressure misestimation and the efficacy of PGAs.

Maculopathies in Glaucoma

In the presence of glaucoma, various changes in the macula can occur during the course of the disease itself or its treatment. Maculopathies that can be observed in glaucoma include cystoid macular edema, hypotony maculopathy, and microcystic macular edema. The following article discusses the pathophysiology, causes, course, clinical presentation, and treatment of these maculopathies.

The effect of topical bimatoprost on corneal clarity in primary open-angle glaucoma: a longitudinal prospective assessment

PURPOSE

To study the effect of topical bimatoprost on the corneal optical density values using a dual Scheimpflug Placido analysis system.

METHODS

This longitudinal case-control study included 18 patients with newly diagnosed primary open-angle glaucoma who received topical bimatoprost as a first-line treatment and 20 healthy individuals (age and sex-matched controls). Corneal densitometry data were obtained using the dual Scheimpflug analyzer at pre-treatment and 1st, 6th, 12th, 18th months of post-treatment. Repeated measures of ANOVA and Pearson correlation tests were used for statistical analysis.

RESULTS

There were statistically significant differences between pre-treatment and post-treatment 1st and 6th months corneal densitometry values (p < 0.001, p = 0.007, respectively). However, there was no statistically significant difference between the post-treatment 12th and 18th months (p > 0.05). Corneal densitometry values decreased during the 1st month. Intraocular pressure (IOP) differences were statistically significant between baseline and 1 month after treatment (P < 0.001), however not statistically significant between the 1st and 6th, 6th and 12th, 12th and 18th months after treatment (p > 0.05, for all). Corneal densitometry was not correlated with IOP (r = - 0.037, p = 0.44). In the control group, there was no statistically significant difference between baseline and post-baseline 18th-month corneal densitometry measurements (p > 0.05).

CONCLUSIONS

Topical bimatoprost administration might result in a decrease in corneal densitometry measurement. It is of clinical importance that topical bimatoprost administration can affect corneal transparency and cause a possible alteration in corneal properties.

Central Corneal Thickness Among Filipino Patients in an Ambulatory Eye Surgery Center Using Anterior Segment Optical Coherence Tomography

Objective

The purpose of the study was to determine the central corneal thickness (CCT) among Filipino patients that may contribute to different glaucoma diagnosis using the anterior segment optical coherence tomography in an ambulatory eye surgery center.

Methods

A single-center retrospective, cross-sectional study design including 1232 eyes of 641 patients of the Asian Eye Institute, Makati, Philippines from January 2019 to December 2019 who had their CCT measured with Visante anterior segment optical coherence tomography (AS-OCT). CCT was correlated with age, sex, presence of diabetes and/or hypertension, and glaucoma diagnosis.

Results

Among 641 patients who had their CCT measured by Visante AS-OCT, 723 eyes of 369 patients were included. Nearly half of the study population were normal or glaucoma suspects. The mean CCT among Filipino patients was 535.59 ± 34.06 µm. Ocular hypertensive patients had the thickest CCT, while normal tension glaucoma patients had the thinnest CCT. After adjusting for multiple variables, CCT had a direct relationship with the presence of diabetes, IOP level and the diagnosis of ocular hypertension, while inverse relationship with age. Most of the patients presenting with angle closure glaucoma were females aged 60 and above.

Conclusion

Visante AS-OCT is a non-contact and non-aerosol generating instrument allaying the fear of disease transmission from contact or aerosolization of tears. Our study confirms similar relationships of CCT with age, presence of diabetes, IOP level, and diagnosis of ocular hypertension or normal tension glaucoma among Filipino patients with the available literature from other ethnicities.

Factors Predetermining Increased Aqueous Humour Flare in Long-Term Glaucoma Treatment

Glaucoma patients often require long-term or even lifelong medical antiglaucomatous treatment. Benzalkonium chloride (BAK) is the most frequently used preservative in medical glaucoma treatment. Laser flare photometry is the noninvasive quantitative measurement of anterior chamber protein level and helps tracking intraocular inflammation. The purpose of our study was to evaluate the ocular aqueous humour flare in glaucoma patients, scheduled for cataract surgery without any other ocular diseases, and the association with pseudoexfoliation (PEX) syndrome, number of medications used, and BAK. A prospective case-control age- and gender-matched study, including open-angle glaucoma patients (>2 years of treatment) with cataract, matched with cataract patients with no other ocular pathology (control group). We found that the aqueous humour flare was higher in the glaucoma group than in the control group. PEX syndrome increased the aqueous humour flare independently from glaucoma diagnosis. The number of used antiglaucomatous medications correlated moderately with the aqueous humour flare. The BAK index showed weak positive correlation with aqueous humour flare. A variety of factors can affect aqueous humour flare increase, including PEX syndrome, medical substance used to treat glaucoma, number of different medications, and presence of BAK. The combination of these factors is of key importance to long-term glaucoma treatment.

Central Corneal Thickness Variances Among Different Asian Ethnicities in Glaucoma and Nonglaucoma Patients

OBJECTIVE

To compare the central corneal thickness (CCT) between different ethnicities and particularly Asian subethnic groups that may contribute to the different glaucoma diagnoses using the optical low-coherence reflectometry technique.

METHODS

A retrospective study of 6 years including 1512 eyes of 929 patients of the Beckman vision center, University of California, San Francisco from 2011 to 2017 had their biometric parameters, including CCT, measured with the Lenstar. Patients were categorized into African Americans, Caucasians, Hispanics, Pacific Islanders, and Asians. Asians were further subcategorized into Chinese, Vietnamese, Koreans, Filipinos, and Japanese.

RESULTS

Among 1356 patients who had their CCT measured by Lenstar from 2011 to 2017, 1512 eyes of 929 patients were included. The study population included 462 Caucasians (52.96%), 60 African Americans (6.46%), 92 Hispanics (9.9%), 32 Pacific Islanders (3.44%), 130 Chinese (13.99%), 52 Filipinos (5.6%), 37 Vietnamese (3.98%), 34 Koreans (3.66%), and 30 Japanese (3.23%). African Americans had the thinnest CCT with a mean of 518.62±40.3 followed by Asians with a mean of 539.29±34.1. Among the Asian study sample, the Chinese had the thinnest CCT with a mean of 537.66±32.5. CCT was adjusted for age, sex, glaucoma diagnosis, diabetes status, and prostaglandin analogs use for >12 months.

CONCLUSIONS

Optical low-coherence reflectometry is a widely used technology, which can measure CCT. Our study confirms that African Americans have the thinnest corneas followed by Asians. In the latter group, relatively thin CCT may partly explain their high rates of normal-tension glaucoma.

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.

Effect of long-term topical latanoprost medication on conjunctival thickness in patients with glaucoma

AIM

To investigate the effect of long-term use of topically administered latanoprost on conjunctival thickness (CT) and conjunctival epithelium thickness (CET) in the patients with glaucoma.

METHODS

A series of 106 glaucomatous patients were included. Of the 106 eyes, 55 eyes were treated with latanoprost eye drops once a day (latanoprost group), while 51 eyes were treated with carteolol hydrochloride eye drops (carteolol group). All the included patients completed a 2-year follow-up. CT and CET were measured with optical coherence tomography (OCT) in all patients at presentation and at 2-year visit, respectively. Statistical analysis was then performed to compare the change in CT and CET.

RESULTS

At presentation, there was no difference in CET (t=0.400, P=0.689) or CT (t=1.14, P=0.259) between the two groups. No significant difference was found in CET (61.65±5.35 µm at baseline, 60.36±6.36 µm at 2-year follow-up, respectively; t=1.977, P=0.0531), while there was a significant decrease in CT from 201.45±14.99 µm at baseline to 167.81±14.57 µm at 2-year visit (t=14.1407, P<0.001) in the latanoprost group. At 2-year follow-up, no statistically difference was found in CET (62.24±5.27 µm; t=1.086, P=0.282) or CT (201.23±12.45 µm; t=1.44, P=0.154) compared to it at baseline (CET: 61.23±5.42 µm; CT: 198.76±13.68 µm, respectively) in the carteolol group.

CONCLUSION

A significant decrease in conjunctival thickness is found in glaucoma patients treated with long-term topical latanoprost; its potential effect on the outcome of filtration surgery should be considered.

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.

The potential impact of recent insights into proteomic changes associated with glaucoma

INTRODUCTION

Glaucoma, a major ocular neuropathy, is still far from being understood on a molecular scale. Proteomic workflows revealed glaucoma associated alterations in different eye components. By using state-of-the-art mass spectrometric (MS) based discovery approaches large proteome datasets providing important information about glaucoma related proteins and pathways could be generated. Corresponding proteomic information could be retrieved from various ocular sample species derived from glaucoma experimental models or from original human material (e.g. optic nerve head or aqueous humor). However, particular eye tissues with the potential for understanding the disease's molecular pathomechanism remains underrepresented. Areas covered: The present review provides an overview of the analysis depth achieved for the glaucomatous eye proteome. With respect to different eye regions and biofluids, proteomics related literature was found using PubMed, Scholar and UniProtKB. Thereby, the review explores the potential of clinical proteomics for glaucoma research. Expert commentary: Proteomics will provide important contributions to understanding the molecular processes associated with glaucoma. Sensitive discovery and targeted MS approaches will assist understanding of the molecular interplay of different eye components and biofluids in glaucoma. Proteomic results will drive the comprehension of glaucoma, allowing a more stringent disease hypothesis within the coming years.

Laser flare-cell photometer: principle and significance in clinical and basic ophthalmology

A slit-lamp examination is an indispensable and essential clinical evaluation method in ophthalmology, but, it is qualitative subjective. To complement its weaknesses in making a quantitative evaluation of flare intensity and number of cells in the aqueous humor in the eye, we invented the laser flare-cell photometer in 1988. The instrument enables a non-invasive quantitative evaluation of flare intensity and number of cells in the aqueous with good accuracy and repeatability as well as maneuverability equal to slit-lamp microscopy. The instrument can elucidate the pathophysiology in the blood-aqueous barrier (BAB) function in a variety of ocular disorders. The accuracy of the instrument makes it possible to investigate not only the pathophysiology of intraocular disorders but also the effects of various drugs and surgical procedures in BAB. The instrument does not only lighten the burden on patients in clinical examinations and study but it also helps minimize the sacrifice of experimental animals and improves the reliability of the results by minimizing inter-individual variations through its good repeatability. Here I shall relate how the instrument has been applied to clinical and basic studies in ophthalmology and what novel knowledge its application contributed to pathophysiology in ophthalmology.

Blood-aqueous barrier integrity in patients with Graves' ophthalmopathy (GO), before and after rehabilitative surgery

PURPOSE

The study was conducted to analyze aqueous flare and its correlations in patients with Graves' ophthalmopathy (GO) undergoing orbital decompression, extraocular muscle, and eyelid surgery. Prospective interventional case series.

PATIENTS AND METHODS

Forty-eight eyes of 27 patients (20 female and 7 male, aged 54.4 ± 5.7) undergoing surgical treatment for GO. Eighteen eyes of nine patients (aged 55.3 ± 3.6) undergoing orbital decompression. Nineteen eyes of 11 patients (aged 54.7 ± 5.6) undergoing extraocular muscle surgery and 13 eyes of 7 patients (aged 53.9 ± 4.9) undergoing eyelid surgery and control group (34 patients aged 53.9 ± 5.1). Laser flare analysis and clinical assessment were performed before surgery and at 1 day, 7 days, and 3 months following surgery.

RESULTS

Aqueous flare was significantly higher in patients with GO (14.03 ± 8.45) before intervention than in the control group (7.89 ± 3.56) (P<0.001), and correlated with Clinical Activity Score and intraocular pressure. In the patients undergoing orbital decompression, flare increased from 17.77 ± 10.63 pc/ms to 38.32 ± 13.56 pc/ms on the first day and 41.31 ± 17.19 pc/ms on the seventh day and returned to 16.01 ± 8.58 pc/ms in 3 months. In patients undergoing extraocular muscle surgery flare increased from 13.05 ± 6.50 to 23.04 ± 11.53 pc/ms (P<0.001) on the first day and returned to 18.02 ± 14.09 pc/ms on the seventh day. Eyelid surgery did not change flare values.

CONCLUSIONS

Orbital decompression disrupts blood-aqueous barrier (BAB). The integrity of BAB returns to preoperative status within 3 months. Extraocular muscle surgery mildly affects BAB integrity, and the effect subsides within 7 days. Eyelid surgery does not affect BAB.

Effects of travoprost in the treatment of open-angle glaucoma or ocular hypertension: A systematic review and meta-analysis

BACKGROUND

A 2005 meta-analysis suggests that lowering intraocular pressure (IOP) in patients with ocular hypertension (OHT) or open-angle glaucoma (OAG) is beneficial in reducing the risk for visual field loss in the long term.

OBJECTIVE

The aim of this meta-analysis was to compare the efficacy and toler-ability of travoprost and latanoprost in patients with OAG or OHT.

METHODS

Pertinent studies published from 1996 to 2008 were identified using systematic searches of major literature databases, including the Cochrane Library, MEDLINE, EMBASE, and the Chinese Biomedicine Database. Internet searches of major search engines, professional associations' Web sites, and manufacturers' databases were also performed. Randomized controlled trials (RCTs) comparing the effects of travoprost 0.004% and latanoprost 0.005% in patients with OAG or OHT were selected. The primary efficacy measure was the weighted mean difference (WMD) in the IOP reduction (IOPR). The primary tolerability measure was the relative risk (RR) for adverse events. The pooled effects were calculated using the random-effects model.

RESULTS

Seventeen studies (1491 patients) were included in the meta-analysis, 4 of which were of poor quality based on Jadad scoring. Travoprost was associated with significantly greater diurnal mean IOPRs compared with latanoprost at 2 weeks and 2 months (WMDs [95% CI] mm Hg: 2 weeks, 1.47 [0.33 to 2.62]; 2 months, 0.71 [0.04 to 1.38]); these values were not significant at 1 (0.81 [-0.78 to 2.40]), 3 (0.01 [-0.50 to 0.52]), and 6 months (0.27 [-0.40 to 0.95]). When the 4 studies of low quality were excluded, no significant treatment differences in diurnal IOPR were found. IOPR measured at 5 pm was significantly greater with travoprost compared with latanoprost at 2 weeks (WMD [95% CI], 0.87 mm Hg [0.40 to 1.33]); these values were not significant at 1 (WMD [95% CI], 0.60 mm Hg [0.00 to 1.20], 2 (0.65 [-0.69 to 1.99]), 3 (0.04 [-0.51 to 0.59]), 6 (0.00 [-0.68 to 0.68]), and 12 months (0.30 [-0.36 to 0.96]). Travoprost was associated with a significantly greater frequency of hyperemia than was latanoprost (RR = 1.72 [95% CI, 1.33 to 2.23]). Rates of serious ocular adverse events did not differ significantly between travoprost and latanoprost (cystoid macular edema: RR = 0.22 [95% CI, 0.03 to 1.76]; cataract: RR = 2.29 [95% CI, 0.90 to 5.83]).

CONCLUSIONS

The findings from the present meta-analysis of these 17 RCTs suggest that there were no significant differences between travoprost and latanoprost in IOPR in these patients with OHT or OAG. Both agents were generally well tolerated.

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.

Effect of latanoprost on central corneal thickness in unilateral normal-tension glaucoma

PURPOSE

To evaluate the effect of latanoprost on central corneal thickness (CCT) in patients with unilateral normal-tension glaucoma (NTG).

METHODS

A total of 38 patients, with unilateral NTG, who were being treated in our glaucoma clinic and were receiving 0.005% latanoprost monotherapy over 24 months, were included in this study. The data were collected, retrospectively, with reviewing of the charts. The mean CCT and the CCT reduction from the baseline were assessed before the treatment, and at 3, 6, 9, 12, and 24 months after the initiation of the treatment. An unaffected eye was also evaluated for the control group. All the measurements were performed with a commercially available ultrasound pachymeter.

RESULTS

There were no significant differences between the eyes for the baseline intraocular pressure and CCT. The mean CCT trend decreased, except at 9 months after the treatment in the latanoprost group (affected eye), but only statistically significant after 24 months of treatment by using paired-sample t-test [544.6±38.4 vs. 540.3±37.8 μm (P=0.013)]. There was no statistically significant changes of CCT between the groups with repeated measures analysis of variance (P=0.635).

CONCLUSION

Topical therapy with latanoprost may decrease the CCT, over a period of 24 months, in patients with NTG. These data should be taken into consideration in a long-standing latanoprost treatment of NTG.

The influence of central corneal thickness on response to topical prostaglandin analogue therapy

OBJECTIVE

Central corneal thickness (CCT) affects intraocular pressure (IOP) readings; however, CCT influence on topical medication efficacy is unknown. We evaluated the IOP-lowering effect of topical prostaglandin analogues (PGAs) in relation to CCT.

DESIGN

Post hoc analysis of a randomized prospective trial.

METHOD

Subjects randomized to a PGA were followed for 24 weeks and were analyzed for relationship between CCT and IOP lowering.

PARTICIPANTS

Patients with either newly diagnosed ocular hypertension or open-angle glaucoma.

RESULTS

75 subjects were enrolled. The mean age was 62.7 ± 10.5 years; 48 were Caucasian. The mean CCT was 562.4 ± 41.4 μ. At repeated measures, ANCOVA analysis showed a significant effect of both baseline IOP (p < 0.0001) and CCT (p = 0.003) on IOP. At week 12, a regression analysis of the effect of CCT on baseline IOP showed that for every 10 μ increase in CCT there was 0.3 mm Hg less IOP decrease from baseline.

CONCLUSIONS

We found a statistically significantly association between a lower mean IOP and a thinner cornea when baseline IOP is controlled for. The magnitude of the relationship is small but may be clinically significant in patients with either very thin or very thick corneas.

Randomized crossover study of latanoprost and travoprost in eyes with open-angle glaucoma

INTRODUCTION

To compare the intraocular pressure (IOP)-lowering effects of 0.005% latanoprost to that of 0.004% travoprost in eyes with open-angle glaucoma (OAG).

METHODS

Forty-two patients with OAG who received either latanoprost or travoprost every evening for 12 weeks, and then switched to the other medication for another 12 weeks. The IOP measurements were made with a Goldmann applanation tonometer (GAT) at the baseline, and at 1, 3, 4, and 6 months after the treatment. The IOP at the untreated baseline and at the end of each treatment period was measured at 10:00, 12:00, and 16:00 hours. The central corneal thickness (CCT) was measured at each visit using an ultrasonic pachymeter.

RESULTS

The mean baseline IOP was 13.9 ± 2.5 mmHg, and the CCT was 536.7 ± 30.5 μm. Latanoprost reduced the IOP by 2.5 ± 1.7 mmHg and travoprost by 2.6 ± 1.5 mmHg from the baseline (p = 0.6807). The CCT decreased significantly to 531.9 ± 30.3 at 3 months (p = 0.0160) and to 529.4 ± 30.5 μm at 6 months (p = 0.0002) after the therapy. The decrease was significantly greater in eyes after travoprost (p = 0.0049).

CONCLUSIONS

Travoprost has similar effect as latanoprost in reducing the IOP in glaucoma patients with relatively low IOPs. The use of prostaglandin analogs can decrease the CCT, and this change should be considered when the IOPs obtained by GAT are analyzed.

Mixed treatment comparison of repeated measurements of a continuous endpoint: an example using topical treatments for primary open-angle glaucoma and ocular hypertension

Mixed treatment comparison (MTC) meta-analyses estimate relative treatment effects from networks of evidence while preserving randomisation. We extend the MTC framework to allow for repeated measurements of a continuous endpoint that varies over time. We used, as a case study, a systematic review and meta-analysis of intraocular pressure (IOP) measurements from randomised controlled trials evaluating topical ocular hypotensives in primary open-angle glaucoma or ocular hypertension because IOP varies over the day and over the treatment course, and repeated measurements are frequently reported. We adopted models for conducting MTC in WinBUGS (The BUGS Project, Cambridge, UK) to allow for repeated IOP measurements and to impute missing standard deviations of the raw data using the predictive distribution from observations with standard deviations. A flexible model with an unconstrained baseline for IOP variations over time and time-invariant random treatment effects fitted the data well. We also adopted repeated measures models to allow for class effects; assuming treatment effects to be exchangeable within classes slightly improved model fit but could bias estimated treatment effects if exchangeability assumptions were not valid. We enabled all timepoints to be included in the analysis, allowing for repeated measures to increase precision around treatment effects and avoid bias associated with selecting timepoints for meta-analysis.The methods we developed for modelling repeated measures and allowing for missing data may be adapted for use in other MTC meta-analyses.

Bimatoprost: a review of its use in open-angle glaucoma and ocular hypertension

Bimatoprost (Lumigan) is a synthetic prostamide that reduces intraocular pressure (IOP) by increasing the outflow of aqueous humour. In patients with open-angle glaucoma or ocular hypertension, long-term treatment (for up to 48 months) with once-daily bimatoprost 0.03% ophthalmic solution was more effective than timolol twice daily in providing a sustained and stable reduction in IOP. Bimatoprost 0.03% ophthalmic solution demonstrated efficacy similar to, or greater than, the prostaglandin analogues latanoprost and travoprost in reducing IOP and achieving target IOP levels. Switching to bimatoprost was as effective in maintaining diurnal IOP control as switching to a fixed combination of latanoprost/timolol (in patients with IOP levels controlled with a nonfixed combination of latanoprost plus timolol), and similarly, or more, effective in lowering IOP and providing overall diurnal IOP control than switching to a combination of dorzolamide/timolol (in patients with IOP inadequately controlled with other antiglaucoma agents including timolol). Treatment with bimatoprost was generally well tolerated, with conjunctival hyperaemia (mostly mild), growth of eyelashes and ocular pruritus being commonly reported. Other adverse events included increases in the pigmentation of the iris, perorbital areas and eyelashes.

Central corneal thickness in subjects with glaucoma and in normal individuals (with or without pseudoexfoliation syndrome)

Objective:

The evaluation of central corneal thickness (CCT) in subjects with pesudoexfoliation glaucoma (PEXG), primary open-angle glaucoma (POAG), and in normotensive individuals with or without pseudoexfoliation syndrome (PXS).

Study design/patients and methods:

CCT was evaluated with ultrasound pachymetry in a total of 179 individuals: 32 had bilateral PEXG, 55 had bilateral POAG, 35 had PXS, and 57 were healthy individuals without PXS.

Results:

CCT in PEXG eyes (526.00 ± 34.30 μm) was significantly thinner compared to POAG eyes (549.36 ± 39.3 μm) (P = 0.027) and normal control eyes with (550.64 ± 39.0 μm) or without PXS (547.36 ± 33.1 μm), (P = 0.039 and 0.048 respectively). No statistically significant difference was found comparing CCT values of POAG eyes to control group eyes.

Conclusion:

The evaluation of CCT is necessary in all patients with glaucoma and especially in those with PEXG due to the thinner cornea and the risk of underestimation of intraocular pressure.

Outcome of raised intraocular pressure in uveitic eyes with and without a corticosteroid-induced hypertensive response

PURPOSE

To compare the management and outcome of raised intraocular pressure (IOP) in uveitis patients with a corticosteroid hypertensive response and those who are noncorticosteroid responders and to determine the impact of intraocular corticosteroid use on IOP in uveitic eyes.

DESIGN

Retrospective study.

METHODS

Eight hundred and ninety-one uveitis patients were observed in a specialized clinic over 3 months. The main outcome measures were frequency, characterization, management, and outcome of uveitis-related ocular hypertension and glaucoma.

RESULTS

Of 891 patients with uveitis, 191 (275 eyes) had IOP elevation (21.4%). Of these, 95 (34.5%) eyes had glaucoma. IOP elevation attributed to corticosteroid-response (61.1%) was controlled more easily than that resulting from other causes (38.9%), requiring fewer eye drops (mean, 2.06 vs 2.52; P = .009) and less filtration surgery (8.9% vs 22.4%). Among eyes with uveitis and raised IOP, elevated IOP developed in 18 eyes (6.5%) after intravitreal triamcinolone, including 64.7% to 30 to 39 mm Hg and 35.3% to 40 mm Hg or more. Prostaglandin analogs were used in 49.2% of 246 eyes; no increase in inflammation was seen in these eyes.

CONCLUSIONS

In this tertiary center series, most instances of raised IOP were attributable to corticosteroid response. Raised IOP induced by corticosteroid response was controlled more easily and less often resulted in optic nerve or visual field changes of glaucoma. Although intravitreous triamcinolone was associated with substantial risk of corticosteroid-response IOP elevation, all cases were controlled medically without experiencing glaucomatous injury. Prostaglandin-induced uveitis was not observed despite extensive use of prostaglandin IOP-lowering agents.