Longitudinal effect of topical antiglaucoma medications on central corneal thickness

Clinical Profile of Primary Open-angle Glaucoma Patients at an Eye Center in Nigeria

Aim

Globally, one of the leading causes of preventable blindness is primary open-angle glaucoma (POAG). The study assessed the clinical presentations of POAG patients attending an eye center in Abuja, Nigeria.

Materials and methods

Records of 188 eyes, collected from 94 patients diagnosed with POAG for a period of 1 year at the eye center, were reviewed. Clinical records, including age, gender, visual acuity (VA), central cornea thickness (CCT), intraocular pressure (IOP), cup-to-disk ratios, and retinal nerve fiber layer (RNFL) thickness of the participants, were extracted and analyzed.

Results

The majority of the participants were males (56.4%) and adults (57.4%), most of whom had normal VA (>70% in each eye). Our analysis revealed normal average estimates of RNFL thickness, IOP, and CCT among the participants. Females had thicker RNFL compared to males (p = 0.02). Although CCT decreased with age (r = -0.28, p = 0.005), there was no such link between IOP and CCT (r = 0.09, p = 0.38).

Conclusion

Central cornea thickness (CCT), RNFL thickness, and IOP in isolation should not be used as early indicators for POAG; rather, a combination of these and other indices is recommended. Early detection through active screening and treatment in the community for at-risk groups is highly advised.

How to cite this article

Ezinne NE, Kwarteng MA, Ekemiri KK, et al. Clinical Profile of Primary Open-angle Glaucoma Patients at an Eye Center in Nigeria. J Curr Glaucoma Pract 2023;17(3):113-117.

Effects of topical prostaglandin therapy on corneal layers thickness in primary open-angle glaucoma patients using anterior segment optical coherence tomography

PURPOSE

To evaluate the effects of latanoprost, bimatoprost, and travoprost eye drops and their preservatives on each corneal layer thickness in patients with primary open-angle glaucoma (POAG).

METHODS

We retrospectively analyzed 79 eyes of 79 patients with POAG who were receiving prostaglandin therapy. Patients were divided into three subgroups according to monotherapy with latanoprost, bimatoprost, and travoprost during a mean of 43.14 ± 19.12 months follow-up period. In addition, the central corneal epithelial thickness (CET), central corneal stromal thickness (CST), and total central corneal thickness (CCT) were measured by anterior segment optical coherence tomography (AS-OCT) at baseline and every six months after treatment initiation at each visit between 9 and 12 o'clock in the morning. Furthermore, intraocular pressure (IOP) was measured with Goldmann applanation tonometry (GAT) after AS-OCT measurements at each visit.

RESULTS

All three groups were not significantly different in age, gender, follow-up period, and mean intraocular pressure values (p > 0.05 for all). The reduction of CCT in the latanoprost, bimatoprost, and travoprost groups was 6.53 ± 3.17, 18.59 ± 8.42, and 10.1 ± 1.13 µm, respectively. The decrease in CST values was 4.65 ± 1.54, 15.84 ± 7.47, 9.69 ± 1.45 µm, and CET values were 1.88 ± 1.66, 2.75 ± 0.73, 0.41 ± 0.54 µm in all groups, respectively. A statistically significant thinning was observed in all corneal layers (p < 0.05) except the CST values in the latanoprost group and CET values in the travoprost group. However, no significant difference was found in the average reduction of CET, CST, and CCT values among the three groups (p > 0.05).

CONCLUSION

Topical treatment with latanoprost, bimatoprost, and travoprost affects each layer of the cornea separately according to the active and protective substances contained in these eye drops. On the other hand, the thinning effect on the corneal layers was similar in these three drugs because there was no significant difference between the three groups in the total amount of thinning of the corneal layers during the follow-up period.

Effect of Topical Prostaglandin Analogue Therapy on Central Corneal Thickness: A Systematic Review

To investigate whether prostaglandin analogue (PGA) eyedrops have a significant effect on central corneal thickness (CCT), we conducted a systematic search of literature published from 2000 to 2021. Among the studies conducted on topical PGA therapy in open-angle glaucoma or ocular hypertension patients over 18 years old, prospective studies with CCT change as an outcome were included. A single-arm meta-analysis was conducted to assess the overall effect on CCT, and subgroup analysis according to exposure time of PGA eyedrops was also performed. We counted the number of articles that reported on severe events (CCT reduction of 25 μm or more) and obtained their proportion. The methodological quality was assessed by the McHarm tool. Twenty-two reports of prospective studies were selected. The results of the single-arm meta-analysis showed very high heterogeneity. Still, in subgroup analysis, when PGA was used for more than 6 months, heterogeneity was low, and a significant decrease in CCT was observed. Severe events were reported in two reports and occurred in 3.8% to 14.8% of participants. PGA eyedrop use may cause a clinically significant CCT decrease, requiring CCT follow-up.

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.

Comparison of corneal, endothelial, and anterior segment parameters in eyes with and without pigment dispersion

BACKGROUND

To evaluate the differences of central corneal thickness (CCT), corneal endothelial cell morphology, and biometric parameters of the anterior chamber and iridocorneal angle in pigment dispersion syndrome (PDS), pigmentary glaucoma (PG), primary open-angle glaucoma (POAG), and healthy group.

METHODS

Twenty- three eyes in the PDS group, 39 eyes in the PG group, 33 eyes in the POAG group, and 45 eyes in the healthy control group were included in this cross-sectional retrospective study. Corneal endothelial cell density, the coefficient of variation in the cell area, hexagonality, and central corneal thickness (CCT) were obtained by specular microscopy (CEM 530, NIDEK, Japan). Anterior chamber depth (ACD), iridocorneal angle parameters and CCT were measured by anterior segment optical coherence tomography (AS-OCT) (Visante OCT, Carl Zeiss AG, Germany).

RESULTS

The mean CCT via specular microscopy (SM-CCT) was measured at the thinnest value in the PG group (531.20 ± 34.91 µm) and the thickest in the control group (569.13 ± 37.52 µm). CV value was higher in PG (34.65 ± 6.84) and POAG group (34.27 ± 9.93) and lower in control group (28.82 ± 5.18) (p = 0,005). The mean AS-OCT-CCT was the thinnest in the PG group (513.61 ± 39.94 µm), and the thickest in the control group (547.04 ± 36.72 µm) (p = 0.001). All parameters of the iridocorneal angle were larger in the PDS and PG groups (p < 0.001). In the correlation analysis of the glaucomatous eyes, a negative correlation between the C/D ratio and SM-CCT and AS-OCT-CCT (p = 0.037, p = 0.017, respectively) and a positive correlation between the pRNFL thickness and AS-OCT- CCT (p = 0.002).

CONCLUSION

CCT values obtained with both SM and AS-OCT were found to be significantly thinner in PG cases. CV, which is the measure of polymegatism, was found to be significantly higher in PG cases.

Do topical antiglaucoma drugs affect the cornea?

To investigate effects of beta blocker (BB; timolol or betaxolol), latanoprost, and latanoprost-timolol combination (LTC) drugs on corneal endothelial cell density (ECD) and central corneal thickness (CCT) in primary open-angle glaucoma (POAG) patients. Sixty-one patients in BB group, 64 patients in latanoprost group, 59 patients in LTC group, and 58 healthy cases in control group were included. Intraocular pressures (IOP), ECDs, and CCTs of groups were recorded at initial (pre-treatment) period, first and third years after treatment, and comparisons were done. In groups, changes of ECDs according to time were not significant (p > 0.05). In BB and control groups, changes of CCTs according to time were not significant (p > 0.05). In latanoprost and LTC groups, CCTs in both first and third years were significantly thinner than initial CCTs (p = 0.039 for latanoprost, p = 0.041 for LTC at first year; p = 0.018 for latanoprost, p = 0.032 for LTC at third year). In latanoprost and LTC groups, CCTs of patients using drugs for 1 year were similar to those of patients using drugs for 3 years (p > 0.05). In our study, uses of BB, latanoprost or LTC did not affect ECD. BB drugs had no effect on CCT. Although latanoprost and LTC appeared to reduce CCT at 3-year follow-up from the statistical point of view, this 8-10 μm difference in CCT was not clinically significant.

Corneal thickness evaluation in healthy eyes: Comparison between two different Scheimpflug devices

Purpose

To evaluate the correlation between corneal thickness (CT) measurements obtained with two Scheimpflug devices, Pentacam HR and Precisio, and to elaborate, if necessary, a regression formula which could make these results comparable.

Design

Retrospective, Comparative, Observational study.

Setting

Department of Medicine, Surgery and Dentistry, “Scuola Medica Salernitana” University of Salerno, Italy

Methods

One hundred twenty four healthy eyes of 124 volunteers (65 males; range: 20–32 years; mean age of 24.8 ± 1.7) were included in this study. CT was measured using Pentacam HR and Precisio in three different points: the pupil center (PC), the corneal apex (CA) and the thinnest point (TP).

Results

CT obtained with both devices at the PC, at the CA and at the TP showed a good correlation (r = 0.97, r = 0.97, r = 0.97, respectively), but Pentacam HR measurements were significantly thicker than those provided by Precisio (p < 0.01). The differences between Pentacam HR and Precisio were 21.9 ± 8.8 μm at the PC, 21.9 ± 8.9 μm at the CA, 19.1 ± 9.0 μm at the TP. The calculated regression formulas were: y = 0.9558x + 2.3196 for the PC, y = 0.9519x + 4.5626 for the CA, y = 0.9364x + 15.436 for the TP, where x is the CT measured with Pentacam HR and y is the Precisio measurement.

Conclusions

The findings provided by this study highlight that Precisio measures thinner corneas compared to Pentacam HR. The identified regression formulas could be utilized to make interchangeable the results obtained with these two devices.

The Glaucoma Italian Pediatric Study (GIPSy): The Long-term Effect of Topical Latanoprost on Central Corneal Thickness

PRECIS

Central corneal thickness (CCT) may increase over time in children affected by primary congenital glaucoma and treated with latanoprost for at least 30 months.

PURPOSE

The purpose of this study was to investigate CCT modification over time in a population of primary pediatric glaucoma (PPG) patients prescribed a monotherapy of latanoprost.

MATERIALS AND METHODS

The present paper reports the results of a post hoc analysis on patients enrolled in the Glaucoma Italian Pediatric Study (GIPSy). Children affected by PPG, with a postsurgical intraocular pressure between 22 and 26 mm Hg and treated with latanoprost monotherapy for at least 30 months were eligible for the analysis. CCT variation from baseline was investigated over the follow-up using univariable and multivariable longitudinal linear mixed models. The impact of age, sex, and intraocular pressure on CCT variation were evaluated taking into account the interaction of each variable with time.

RESULTS

Twenty-seven eyes (20 patients) were included in the analysis. Mean duration of latanoprost treatment was 36.6 months (SD 2.5) and mean CCT at baseline was 551 μm (SD 37.7). A significant increase of CCT over time was revealed by multivariable analysis, taking into account the impact of age at baseline and its interaction with time (P=0.03). The interaction between age and time was significant (P=0.04), indicating that older age at baseline was associated with lower increase of CCT over time. No variation of CCT was found in univariable analysis (P=0.28).

CONCLUSION

In this population of PPG patients treated with latanoprost for at least 30 months, CCT significantly increased over time, when the impact of age and its interaction with time were considered.

Effect of Prostaglandin Analogues on Central Corneal Thickness: 3-Year Follow-up Results

PURPOSE

To evaluate the effects of each subgroup of prostaglandin analogues (PGAs) on central corneal thickness (CCT) in patients with normal tension glaucoma (NTG).

METHODS

We retrospectively reviewed 55 eyes of 55 patients with NTG who were receiving PGA therapy. Patients who were treated with 0.005% latanoprost (16 eyes), 0.0015% tafluprost (16 eyes), or 0.004% travoprost (23 eyes) monotherapy were included. CCT assessments were performed at baseline and 1, 2, and 3 years after initiation of treatment.

RESULTS

In the NTG group, the mean CCT showed a decreasing trend, and there was a significant difference in mean CCT at 1, 2, and 3 years compared with baseline (baseline, 538.16 ± 32.14; 1 year, 526.55 ± 37.30 µm [p = 0.00]; 2 years, 521.67 ± 36.79 µm [p = 0.00]; 3 years, 520.43 ± 36.88 µm [p = 0.00]). The reduction of CCT was confirmed by subgroup analysis. In the 0.005% latanoprost group, mean CCT was decreased at 1 year (p = 0.11), 2 years (p = 0.00), and 3 years (p = 0.02). In the 0.0015% tafluprost group and the 0.004% travoprost group, mean CCT was also significantly decreased at all years (p = 0.00). No statistical difference was observed between the NTG subgroups (p = 0.06).

CONCLUSIONS

Topical therapy with PGAs appeared to cause a significant decrease in CCT reduction in patients with NTG. A long-term follow-up study including more participants is needed.

Effects of Netarsudil and Latanoprost Alone and in Fixed Combination on Corneal Endothelium and Corneal Thickness: Post-Hoc Analysis of MERCURY-2

INTRODUCTION

To describe the changes in endothelial cell density (ECD), the coefficient of variation (CV), the percentage of hexagonal cells (%HEX), and central corneal thickness (CCT) following 3 months of therapy with netarsudil 0.02%/latanoprost 0.005% fixed combination, and to compare these changes with those seen with netarsudil 0.02% or latanoprost 0.005% in eyes with ocular hypertension or open-angle glaucoma.

METHODS

A subset of subjects enrolled in a Phase 3 evaluation of the intraocular pressure-lowering efficacy and safety of netarsudil 0.02%/latanoprost 0.005% fixed combination once daily (QD) versus each of its individual components underwent corneal endothelial cell imaging by specular microscopy and ultrasound pachymetry at baseline and following 3 months of therapy. Images were evaluated in masked fashion at an independent reading center. Changes from baseline to 3 months in ECD, CV, %HEX, and CCT were compared between treatment groups.

RESULTS

Data from 415 subjects obtained at both baseline and Month 3 were included in this post hoc analysis. Changes from baseline to Month 3 in ECD, CV, and %HEX were clinically insignificant in all three groups, and the changes in the netarsudil/latanoprost fixed combination group demonstrated no statistical difference from those seen in the netarsudil and latanoprost groups. Mean CCT decreased more in the fixed combination group (- 6.4 µm) than in either the netarsudil group (- 3.3 µm, p = 0.0248) or the latanoprost group (- 1.2 µm, p < 0.0001).

CONCLUSIONS

Netarsudil 0.2%/latanoprost 0.005% fixed combination QD for 3 months in eyes with ocular hypertension or open-angle glaucoma had no clinically significant effects on endothelial cell density or morphology. The significant decrease in CCT in the fixed combination group compared to the two individual component groups may indicate that the potential effects of each drug on CCT are additive, although the magnitude of the observed effects is likely of negligible clinical significance. CLINICALTRIALS.

GOV IDENTIFIER

NCT02674854.

Evaluation of corneal epithelial thickness in glaucomatous patients using anterior-segment optical coherence tomography

The corneal epithelium represents one of the main structures that undergo degenerative alterations due to antiglaucomatous therapy. Chronic glaucoma therapy containing benzalkonium chloride induces epithelial cellular changes and inflammatory infiltration that in turn causes ocular surface changes resulting in ocular discomfort. Also, age-related changes can involve the tear film stability and the corneal epithelium surface with reduction of microvilli. The objective of this study is to gain insights about the changes in corneal epithelium in glaucomatous patients divided according to age, type and duration of therapy using anterior-segment optical coherence tomography (AS-OCT). This study evaluated a total of 81 eyes of 42 patients for whom corneal epithelium thickness (CET) was measured in different sectors of the cornea. Our results showed no significant differences in CET among patients divided according to type and duration of treatment, while younger patients showed a thinner CET in comparison with older patients. AS-OCT results demonstrated that the physiological age-related alterations contributed to corneal epithelium changes in patients undergo chronic antiglaucoma therapy.

Effects of aging on corneal parameters measured with Pentacam in healthy subjects

Our purpose was to prospectively analyze the age-related changes of corneal Scheimpflug parameters in healthy subjects. Thirty-five eyes of 35 volunteers (age 14-67 years) were investigated with an average interval of 3.6 years. Changes of corneal parameters (flattest keratometric reading at anterior (K1F) and posterior surface (K1B), steepest keratometric reading at anterior (K2F) and posterior surface, anterior astigmatism, posterior astigmatism (AstigB), flat axis of anterior and posterior astigmatism (AxisB), thinnest pachymetric value (PachyMin), corneal volume (CV10-mm)) were analyzed. K1F and K2F decreased significantly during observation and showed stronger decrease in younger than in older individuals. Higher values proved to be more stable. K1B decreased significantly and the degree of decrease was dependent on its baseline value and age: in young subjects low values increased, high values decreased. AstigB decreased significantly and showed a baseline-dependent significant increase from lower and a significant decrease from higher initial values. Over time, the mean AxisB shifted significantly. PachyMin and CV decreased significantly with age, especially from higher baseline values in younger subjects. The results of this longitudinal study suggest that both corneal surfaces change significantly with age. We demonstrate for the first time that age and baseline values influence age-related changes of corneal parameters.

Effect of Acute Increases in Intraocular Pressure on Corneal Pachymetry in Rabbit Eyes Treated with Timolol Maleate

Objective:

To evaluate in an in vivo rabbit model, the effect of topical timolol maleate therapy on the central corneal thickness response to acute intraocular pressure increases.

Method:

In this prospective and interventional controlled study, the central corneal thickness and intraocular pressure were measured in vivo in 12 rabbit eyes treated with topical timolol maleate for 1 month and in 12 controls at baseline, and after the intraocular pressure (measured by direct cannulation of the anterior chamber) was increased to 15 and 30 mmHg using a forced saline infusion into the anterior chamber.

Results:

There were no significant differences in the basal central corneal thickness values (control group, 373.2±12.9 µm; study group, 377.5±19.2 µm, p=0.5) or the central corneal thickness values when the intraocular pressure was increased to 15 mmHg (control group, 335.2±14.3 µm; study group, 330.0±32.1 µm, p=0.6) and to 30 mmHg (study group, 318.8±25.3 µm; control group, 329.8±21.0 µm, p=0.3).

Conclusion:

Rabbit corneas treated with topical timolol maleate for 1 month did not show a strain response to acute intraocular pressure increases that differed from control eyes. This is in contrast to a previous finding in which rabbit eyes treated with prostaglandin analogues had a greater decrease in central corneal thickness in response to a sudden intraocular pressure increase compared with untreated corneas.

Characteristics of corneal biomechanical responses detected by a non-contact scheimpflug-based tonometer in eyes with glaucoma

PURPOSE

To determine the corneal biomechanical properties in eyes with glaucoma using a non-contact Scheimpflug-based tonometer.

METHODS

Corneal biomechanical responses were examined using a non-contact Scheimpflug-based tonometer. The tonometer parameters of the normal control group (n = 75) were compared with those of the glaucoma group (n = 136), including an analysis of glaucoma subgroups categorized by visual field loss.

RESULTS

After adjusting for potential confounding factors, including the intraocular pressure (IOP), central corneal thickness (CCT), age and axial length, the deformation amplitude was smaller in the glaucoma group (1.09 ± 0.02 mm) than in the normal control group (1.12 ± 0.02 mm; p value = 0.031). The deformation amplitude and the deflection amplitude of the severe glaucoma group (1.12 ± 0.02 mm and 0.92 ± 0.01 mm) were significantly greater than that of the early glaucoma group (1.07 ± 0.01  mm and 0.88 ± 0.11 mm, p = 0.006 and p = 0.031), whereas that of the moderate glaucoma group (1.09 ± 0.02 mm and 0.90 ± 0.02 mm) was greater than that of the early glaucoma group, but this difference was not statistically significant. The deformation amplitude showed a negative correlation with the CCT in the normal control group (r = -0.235), with a weaker negative relationship observed in the early glaucoma group (r = -0.099). However, in the moderate and severe glaucoma groups, the deformation amplitude showed a positive relationship with the CCT, showing an inverse relationship. The duration and number of antiglaucomatous eyedrops used had negative correlations with the CCT in eyes with moderate and severe glaucoma.

CONCLUSION

Overall, the glaucoma group showed significantly less deformable corneas than did the normal controls, even after adjusting for the IOP, CCT, age and axial length. However, there were also differences according to the severity of glaucoma, where the corneal deformation amplitude was greater in the severe glaucoma group compared to the early glaucoma group. The combined effects of stiffening due to glaucoma and increased viscoelastic properties caused by the chronic use of antiglaucomatous eyedrops may have resulted in the present findings.

Change in Central Corneal Thickness After the Discontinuation of Latanoprost in Normal Tension Glaucoma-Change in Central Corneal Thickness After Stop of Latanoprost

PURPOSE

To assess the impact of latanoprost on central corneal thickness (CCT) after ceasing medication in patients with normal tension glaucoma (NTG).

METHODS

A total of 46 eyes from 46 NTG patients, and 44 eyes from 44 individuals with glaucoma suspect (controls), were included in this retrospective study. Newly diagnosed early NTG patients (visual field mean deviation >-6.00) were administered latanoprost 0.005% monotherapy once a day. CCTs were measured by ultrasound pachymetry before treatment, for 5 years during treatment, and for 2 years after ceasing treatment.

RESULTS

Mean CCT was reduced significantly in the NTG group during treatment [544.4 ± 35.8 μm vs. 531.4 ± 32.5 μm (n = 46), P < 0.001]. After ceasing latanoprost treatment, mean CCT increased [531.4 ± 32.5 μm vs. 544.6 ± 37.1 μm (n = 46), P < 0.01] over the course of 2 years. In the control group, however, mean CCT was not significantly different [553.5 ± 27.5 μm vs. 561.8 ± 24.7 μm (n = 44), P = 0.06] at the 7-year follow-up.

CONCLUSIONS

Latanoprost significantly reduced CCT in NTG patients after 5 years of treatment; however, the reduction was reversed 2 years after discontinuation of treatment.

Ocular surface toxicity from glaucoma topical medications and associated preservatives such as benzalkonium chloride (BAK)

INTRODUCTION

This review discusses the evidence concerning the effect of topical medications and their preservatives on the ocular surface in glaucoma patients. The role of topical anti-glaucoma medication remains critical in the management of chronic glaucoma worldwide but the beneficial effects of treatment are counterbalanced by the adverse effects of corneal and conjunctival toxicity. Areas covered: This article covers the effect of topical ocular drops and preservatives, particularly benzalkonium chloride, on the cornea and conjunctiva. Both basic science and clinical evidence will be presented. The first part reviews the relationship between ocular surface disease and benzalkonium chloride and the evidence from non-benzalkonium chloride preserved drops. The second part discusses the effects of benzalkonium chloride on the histopathology of the conjunctiva and its impact on clinical care as well as quality of life. Expert opinion: Topical anti-glaucoma medication will continue to be used in the management of this blinding disease for the foreseeable future. Treatment outcomes will benefit from minimized exposure to benzalkonium chloride. The development of alternative preservatives, preservative-free topical options, and non-drop therapeutics such as drug-eluting systems for the delivery of ocular medications, will be very helpful in the care of glaucoma patients.

[Differentiation of ocular hypertension]

The term ocular hypertension has been used for more than 30 years. It is defined as an elevated intraocular pressure above the statistical norm without detectable optic nerve head or visual field damage. The number of patients with ocular hypertension in Germany is estimated to be approximately 3-5 million. Increased intraocular pressure is a risk factor for conversion to primary open-angle glaucoma. Most patients with ocular hypertension (and no risk factors) can be followed on a regular basis without any treatment. Each visit should include measurement of intraocular pressure, optic nerve head examination with a slit lamp, imaging and perimetric examinations. Currently known risk factors are high intraocular pressure, higher age, myopia, a thin cornea and darkly pigmented skin. If risk factors are present, antiglaucomatous therapy is indicated.

Effect of supine body position on central corneal thickness

BACKGROUND

To evaluate the effect of supine body position on central corneal thickness (CCT) in open-angle glaucoma patients and in healthy subjects.

DESIGN

A cross-sectional study at a university eye clinic.

PARTICIPANTS

Twenty-three subjects were recruited in each group, for a total of 46 patients.

METHODS

CCT was measured using an ultrasound pachymeter in each subject. Three consecutive measurements in each eye were first taken in the sitting position, and repeated after 10 min and 30 min in a supine position. Results were analyzed using mixed model repeated measures, which adjusted for age, gender and laterality of eyes.

MAIN OUTCOME MEASURES

CCT RESULTS: In healthy subjects, CCT decreased with supine positioning at 10 min (mean = -5.2 µm, P = 0.0043) and at 30 min (mean = -6.5 µm, P < 0.0001). In the glaucoma group, CCT decreased with supine positioning at 10 min (mean = -6.7 µm, P = 0.0043) and at 30 min (mean = -10.2 µm, P < 0.0001). There was no statistically significant difference between the CCT at 10 min supine and at 30 min supine in the healthy subjects (P = 0.37) and glaucoma patients (P = 0.14). CCT was shown to decrease linearly over time (P < 0.0001), and the slopes were not statistically different between groups (P = 0.40).

CONCLUSIONS

CCT is a dynamic measurement that can be influenced by body position. It decreases linearly in the first 30 min of supine positioning at a similar rate in both open angle glaucoma patients and in healthy subjects.

In vitro Effects of Prostaglandin Analogs on Cultured Astrocytes Obtained from the Lamina Cribrosa

PURPOSE

To evaluate the effects of prostaglandin analogs (PGAs) on cell viability and apoptosis in cultured astrocytes obtained from the lamina cribrosa (LC) of the human optic nerve head (ONH).

METHODS

Astrocytes were cultured from LC samples obtained from human donor ONH and treated with three kinds of acid form of PGAs: latanoprost (LAT-A), tafluprost (TAF-A), and bimatoprost (BIM-A) (0.1, 1, 10, 50 and 100 ug/mL). Cell viability was assessed using the WST-1 assay. Cell apoptosis was measured using the deoxynucleotidyl transferase (TdT)-mediated dUTP nick end-labeling (TUNEL) assay. Apoptotic protein expression was evaluated using western blot analysis.

RESULTS

ONH astrocytes expressed FP receptor in western blot analysis. In the presence of 0.1 ug/mL of LAT-A, BIM-A, and TAF-A, the cell viability was 85%, 85% and 82%, respectively. WST-1 assay revealed about 50% of cell viability following treatment with 50 ug/mL of all PGAs. After exposing astrocytes to 10 ug/mL of each PGA for 24 hours, apoptotic cells were stained in TUNEL assay. Western blot analysis revealed that the PGAs up-regulated Bax (pro-apoptotic protein) and down-regulated Bcl-xL (anti-apoptotic protein) in the astrocytes.

CONCLUSIONS

PGAs affected cell viability in cultured astrocytes obtained from human ONH LC. PGA treatment may induce apoptosis in ONH astrocytes.

The impact of central corneal thickness on the risk for glaucoma in a large multiethnic population

PURPOSE

To investigate the relationship between central corneal thickness (CCT) and demographics, and determine whether CCT may be a substantial mediator of the relationships between glaucoma and its demographic risk factors.

METHODS

This cross-sectional study included patients in the Kaiser Permanente Northern California health plan from January 1, 2007 to December 31, 2011 who were 40 years and older and had a documented CCT measurement (N=81,082). Those with any cornea-related diagnoses or a history of corneal refractive surgery were excluded. Demographic characteristics, including age, sex, and race/ethnicity, as well as clinical information including glaucoma-related diagnosis, diabetic status, CCT, and intraocular pressure were gathered from the electronic medical record.

RESULTS

Multivariate linear regression analysis indicated that female sex, increased age, and black race were significantly associated with thinner corneas. A subgroup analysis among Asians revealed that Chinese, Japanese, and Koreans had corneas 6 to 13 µm thicker than South and Southeast Asians, Filipinos, and Pacific Islanders for each diagnosis (P<0.001). In our population, 24.5% (N=19878) had some form of open-angle glaucoma; 21.9% (N=17,779) did not have any glaucoma-related diagnosis. Variation in CCT accounted for only 6.68% [95% confidence interval (CI), 6.14%-7.24%] of the increased risk of open-angle glaucoma seen with increasing age, but explained as much as 29.4% (95% CI, 27.0%-32.6%) of the increased risk of glaucoma seen among blacks, and 29.5% (95% CI, 23.5%-37.0%) of the increased risk of glaucoma seen among Hispanics.

CONCLUSIONS

CCT seems to explain a substantial portion of the increased risk of glaucoma seen among blacks and Hispanics.

Evaluation of corneal endothelium in adolescents with juvenile glaucoma

Purpose. To evaluate the endothelial cell density (ECD) and central corneal thickness (CCT) in adolescents with juvenile open-angle glaucoma (JOAG) and ocular hypertension (OH) and to investigate the influence of topical antiglaucoma medications on ECD and CCT in adolescents with JOAG. Methods. ECD and CCT were investigated in 66 eyes of 33 adolescents with JOAG. Depending on the topical treatment the eyes were classified into 4 groups: (1) topical carbonic anhydrase inhibitor, (2) prostaglandin analogs, (3) beta-blocker, and (4) CAI-beta-blocker combination. ECD and CCT were also checked in 24 adolescents with OH and in control group (33 persons). Results. ECD was significantly lower in eyes with JOAG (2639.5 cells/mm²) compared with ECD in eyes with OH (2924.5 cells/mm²) and in control group (2955.5 cells/mm²). CCT was 0.554 mm in eyes with JOAG, 0.55 mm in eyes with OH, and 0.544 mm in control group. ECD in patients with JOAG was 2730 cells/mm² (1 group), 2773.5 cells/mm² (2 group), 2539.5 cells/mm² (3 group), and 2551 cells/mm² (4 group). CCT was 0.556 mm in 1 group, 0.558 mm in 2 group, 0.532 mm in 3 group, and 0.544 mm in 4 group. Conclusions. Our findings indicate that JOAG and OH did not affect CCT, but JOAG has influence on ECD in adolescents. There were no significant differences between ECD and CCT of eyes treated with different kinds of antiglaucoma medications.