Glaucoma Treatment Patterns in Sub-Saharan Africa

PRCIS

Physicians were most likely to recommend primary medical therapy upon diagnosis of glaucoma. Laser therapy was underutilized where they were available. Physicians were more likely to recommend surgery in severe glaucoma, laser therapy in mild glaucoma, while recommendation of medical therapy did not depend on glaucoma severity.

PURPOSE

To characterize treatment patterns for newly diagnosed glaucoma in sub-Saharan Africa (SSA).

METHODS

This was a multicenter cross-sectional study of adults newly diagnosed with glaucoma at 27 eye care centers in 10 African countries. In addition to demographic and clinical data, physician treatment recommendations (medication, laser, surgery, or no treatment) were recorded. Statistical analyses were performed using STATA version 14.0.

RESULTS

Data from 1201 patients were analyzed. Physicians were most likely to recommend primary medical therapy upon diagnosis of glaucoma (69.4%), with laser (13.2%), surgery (14.9%), and no treatment (2.5%) recommended to the remaining patients. All sites had medical therapy available and most (25/27, 92.6%) could provide surgical treatment; only 16/27 (59.3%) sites offered laser, and at these sites, 30.8% of eyes were recommended to undergo primary laser procedures. As glaucoma severity increased, the laser was recommended less, surgery more, and medications unchanged. Patient acceptance of medical therapy was 99.1%, laser 88.3%, and surgery 69.3%.

CONCLUSIONS

Medical therapy for first-line glaucoma management is preferred by most physicians in SSA (69%). Laser therapy may be underutilized at centers where it is available. These findings underscore the need for comparative studies of glaucoma treatments in SSA to inform the development of evidence-based treatment guidelines and of programs to reduce glaucoma blindness in SSA. Strategic approaches to glaucoma therapy in SSA must address the question of whether medical therapy is the most optimal first-line approach in this setting.

The social construction of genomics and genetic analysis in ocular diseases in Ibadan, South-western Nigeria

Genomics, an emerging field to improve public health practice, has potential benefits to understanding ocular diseases. This study explored the social construction of genomics in ocular diseases in the blind community in Ibadan, Nigeria, through two focus group discussions and twelve in-depth interview sessions conducted among people living with ocular disorders. The data were thematic and content-analysed. Although the participants had limited knowledge about ocular diseases, genomics, and their nexus, they maintained a positive attitude toward its potential benefits. This informed their willingness to participate in genomics testing for ocular diseases. The participants preferred saliva-based sample collection over blood-based, and expressed concern for the procedure and accrued benefits of genomics studies. Thus, public sensitisation about ocular diseases and client-centred genomics testing procedures should be engendered.

Clinical outcomes following selective laser trabeculoplasty in Afro-Caribbean patients with glaucoma at high risk for progression

AIM

To characterise clinical outcomes following selective laser trabeculoplasty (SLT) in eyes of Afro-Caribbean patients with open-angle glaucoma (OAG) at high risk for progression.

METHODS

In a prospective interventional case series, patients meeting high-risk criteria (advanced disease, unilateral glaucoma blindness, inadequate intraocular pressure (IOP) on >2 medications, recent progression on medications, inability to administer, afford or tolerate medications) underwent bilateral 360° SLT and managed based on their subsequent clinical course. Patient-specific indications for SLT-IOP reduction (IOP group) or reduced reliance on medical therapy (MED group)-were recorded before treatment. IOP and medication use were recorded every 3-4 months through up to 24 months of follow-up. Outcomes were analysed separately in the IOP and MED groups.

RESULTS

Among 33 right eyes (left eye outcomes were similar) in the IOP group, mean (SD) IOP was significantly reduced from 21.7 (7.5) mm Hg to 16.2-17.1 mm Hg over follow-up (p<0.0177); medication use remained unchanged (p>0.05) at all time points. Among 36 right eyes in the MED group, mean medication use was 1.9 (0.9) at baseline and ranged from 1.2 to 1.4 medications per eye through follow-up (p<0.0033), and mean IOP was significantly reduced at months 1-6 (to 13.1 (2.3) mm Hg, p=0.0013), months 13-18 (to 14.3 (2.8), p=0.0136) and unchanged at other time points. No vision-threatening adverse events occurred.

CONCLUSIONS

Afro-Caribbean patients with OAG at risk for progression can achieve clinically and statistically significant reductions in IOP or medications through up to 24 months following a single 360° SLT treatment.

TRIAL REGISTRATION NUMBER

NCT02375009.

Long-Term Outcomes of Selective Laser Trabeculoplasty for Open-Angle Glaucoma in the Caribbean

PURPOSE

To characterize long-term clinical outcomes of monotherapy selective laser trabeculoplasty (SLT) in Afro-Caribbean patients with open-angle glaucoma (OAG).

DESIGN

This was a post hoc analysis of nearly 8 years (median, 3.2; interquartile range, 2.1-7.1) of pooled data from the West Indies Glaucoma Laser Study and its preliminary study.

METHODS

Setting: Three eye care practices in Saint Lucia and Dominica.

PARTICIPANTS

Afro-Caribbean adults with mild-moderate OAG treated with ≤2 medications (61 in preliminary study, 72 in West Indies Glaucoma Laser Study).

INTERVENTION

Participants underwent medication washout, baseline intraocular pressure (IOP) determination, and bilateral 360-degree SLT. Participants were followed for up to 94 months. Repeat SLT was performed according to prespecified criteria.

MAIN OUTCOME MEASURES

The primary outcome was mean IOP reduction from baseline. The secondary outcome was medication-free survival with SLT repeated as needed.

RESULTS

The pooled data set included 265 eyes of 133 Afro-Caribbean participants. The mean (standard deviation) baseline IOP was 21.2 (3.4) and 21.2 (3.9) mmHg in right and left eyes, respectively. Over 8 years, the mean IOP ranged from 12.8 to 15.7 mm Hg and from 13.1 to 15.8 mm Hg, respectively (P < .0001 for every comparison with baseline). The median medication-free survival time for initial SLT was 85.4 months in both eyes. The 94-month medication-free survival of SLT repeated as needed was 71.2% and 71.7%, respectively.

CONCLUSIONS

Monotherapy SLT, repeated as needed, safely provides significant IOP reductions in most Afro-Caribbean adults with primary OAG through nearly 8 years of follow-up and has significant potential to delay or prevent glaucoma-related vision loss in black patients in low-resource regions.

Assessing the Reliability of Intraocular Pressure Measurements Using Rebound Tonometry

PRECIS

In a trio of prospective studies, the iCare rebound tonometer demonstrated significantly lower test-retest variability than Goldmann tonometry with good interoperator and interdevice reproducibility, supporting its value in monitoring intraocular pressure (IOP) changes over time.

PURPOSE

The purpose of this study was to characterize intraoperator and interoperator and interdevice reliability of IOP measurements with rebound tonometry (RT, ic100).

METHODS

Three prospective cross-sectional studies were conducted in distinct sample of adult patients with established glaucoma, suspected glaucoma, or no glaucoma at the West Virginia University Eye Institute. Participants in study 1 underwent 5 RT measurements in one randomly selected eye and 5 Goldmann tonometry measurements in the fellow eye by 1 operator; intraoperator variability was compared using the F test. In study 2, 3 operators each obtained 3 RT measurements in participants in randomized operator order. In study 3, a single operator collected 3 measurements each with 3 RTs in randomized device order. Between-operator and between-device reproducibility were characterized using intraclass correlation coefficients (ICCs).

RESULTS

Overall, 28, 19, and 25 subjects participated in the 3 respective studies. Within-subject variance across subjects was 0.757 in RT measurements and 2.471 in Goldmann measurements (P=0.0035). Interoperator reproducibility of RT measurements was good in both eyes [ICC for right eyes 0.78, 95% confidence interval (CI): 0.60-0.85; ICC for left eyes 0.75, 95% CI: 0.50-0.83]. Interdevice reproducibility of RT measurements was good approaching excellent (ICC for right eyes 0.87, 95% CI: 0.83-0.90; ICC for left eyes 0.89, 95% CI: 0.86-0.91).

CONCLUSIONS

The RT's lower measurement variability and good interoperator and interdevice reproducibility suggest that it can characterize IOP changes over time more robustly than Goldmann tonometry, aiding clinicians in assessing the effectiveness of glaucoma therapy and the consistency of IOP control.

Eyes of Africa: The Genetics of Blindness: Study Design and Methodology

BACKGROUND

This report describes the design and methodology of the "Eyes of Africa: The Genetics of Blindness," a collaborative study funded through the Human Heredity and Health in Africa (H3Africa) program of the National Institute of Health.

METHODS

This is a case control study that is collecting a large well phenotyped data set among glaucoma patients and controls for a genome wide association study. (GWAS). Multiplex families segregating Mendelian forms of early-onset glaucoma will also be collected for exome sequencing.

DISCUSSION

A total of 4500 cases/controls have been recruited into the study at the end of the 3rd funded year of the study. All these participants have been appropriately phenotyped and blood samples have been received from these participants. Recent GWAS of POAG in African individuals demonstrated genome-wide significant association with the APBB2 locus which is an association that is unique to individuals of African ancestry. This study will add to the existing knowledge and understanding of POAG in the African population.

Low-energy Selective Laser Trabeculoplasty Repeated Annually: Rationale for the COAST Trial

The recent Laser in Glaucoma and Ocular Hypertension Trial provided the evidentiary basis for a paradigm shift away from the historical medication-first approach to glaucoma--which has numerous limitations, the most important of which is poor adherence to therapy --and toward a laser-first approach. Now 20 years after its commercialization, selective laser trabeculoplasty (SLT) is routinely performed consistently with its initial description, with energy titrated to the appearance of fine, champagne-like cavitation bubbles. A recent data set suggested that lower energy SLT, applied as primary therapy and repeated annually irrespective of intraocular pressure--rather than pro re nata when its effect wanes and irrespective of intraocular pressure rises --yields longer medication-free survival than standard energy SLT repeated pro re nata. A new study--Clarifying the Optimal Application of SLT Therapy --has been initiated to explore this preliminary finding in a pair of consecutive randomized trials. Herein, we provide an evidence-based rationale for the use of low-energy SLT repeated annually as primary therapy for mild to moderate primary open-angle glaucoma or high-risk ocular hypertension.

The Effects of Glaucoma and Glaucoma Therapies on Corneal Endothelial Cell Density

A healthy corneal endothelium is required for corneal clarity. Both the glaucoma disease state and its various forms of treatment can have adverse effects on the corneal endothelium. Both the presence of glaucoma and the magnitude of intraocular pressure elevation are related to endothelial cell loss (ECL). Topical medical therapy, laser procedures, and both traditional surgeries-trabeculectomy and tube-shunts-and newer minimally invasive glaucoma surgeries have variable effects on ECL. This review will summarize the reported effects of glaucoma and its treatment on ECL. Concerns for corneal endothelial cell health should be part of the decision-making process when planning glaucoma therapy for lowering intraocular pressure, with added caution in case of planned device implantation in eyes with preexisting ECL and low endothelial cell density at high risk for corneal endothelial decompensation.

Crystalline lens changes after selective laser trabeculoplasty in Afro-Caribbean patients with open-angle glaucoma; report 4 of the West Indies Glaucoma Laser Study (WIGLS)

PURPOSE

To characterize changes in nuclear, cortical, and posterior subcapsular lens opacities after selective laser trabeculoplasty (SLT) in Afro-Caribbean eyes with primary open-angle glaucoma (POAG).

SETTING

Three clinical practices, Saint Lucia and Dominica.

DESIGN

Prospective case series.

METHODS

Patients with POAG in the West Indies Glaucoma Laser Study (WIGLS) had 360-degree SLT after medication washout. No antiinflammatory therapy was used after SLT. Nuclear, cortical, and posterior subcapsular lens opacities were graded through dilated pupils using the Lens Opacification Classification System III (LOCS III) at baseline and 12, 24, and 36 months after SLT, with the grader masked to all previous values after baseline assessment. Changes in opacity scores from baseline were evaluated using paired t tests.

RESULTS

Seventy-two patients (142 phakic eyes) were evaluated. The mean (±SD) baseline LOCS III opacity scores in right eyes and left eyes, respectively, were 2.44 ± 1.23 and 2.40 ± 1.16 (nuclear), 0.39 ± 1.08 and 0.30 ± 0.85 (cortical), and 0.22 ± 0.59 and 0.15 ± 0.36 (posterior subcapsular). Other than a small improvement in bilateral nuclear opacity scores at 12 months, no statistically or clinically significant changes in any opacity score occurred in either eye up to 36 months postoperatively. Three eyes (2.1%) with preexisting lens opacities had cataract surgery for progressive lens changes at 3 months, 21 months, and 26 months, respectively, after SLT.

CONCLUSIONS

Selective laser trabeculoplasty was not associated with clinically significant changes in nuclear, cortical, or posterior subcapsular lens opacities in glaucomatous Afro-Caribbean eyes. The rate of cataract surgery is consistent with reported rates from longitudinal natural history studies in Caribbean and non-Caribbean populations.

The Rationale for Selective Laser Trabeculoplasty in Africa

Glaucoma is the leading cause of irreversible blindness in Africa. The condition is treatable but not curable. There are numerous obstacles to glaucoma care in Africa, including availability, accessibility and affordability of treatments, as well as medication nonadherence among patients. Medical therapy is costly relative to the average income in Africa and it requires daily self-dosing by patients. Surgery is of limited availability in many regions in Africa, and a high proportion of patients refuse surgery because it is expensive. Selective laser trabeculoplasty (SLT) proves to be a favorable alternative to medical or surgical care, as it is highly effective and safe in people of African descent, more cost-effective than medical therapy, quick and easy to perform, and portable. The procedure also requires no postoperative care, thus obviates the issue of nonadherence. In uncontrolled studies, SLT has a high response rate and it lowers intraocular pressure by 30% to 40%, which exceeds the goal in international guidelines for initial therapies. The African Glaucoma Consortium (AGC), a member-driven stakeholder collective, has been formed in part to develop the infrastructure for continent-wide improvements in glaucoma care. It embraces SLT as a potential key tool in their development plans. The mission of AGC includes improving clinical care by educating existing and new health care professionals to expand the provider network, by conducting trials to identify optimal care strategies for glaucoma in Africa, and by facilitating the development of an integrated network of Centers of Excellence to bring SLT and other crucial glaucoma therapies to communities throughout Africa.

Cataract surgery and nonsteroidal antiinflammatory drugs

Nonsteroidal antiinflammatory drugs (NSAIDs) have become an important adjunctive tool for surgeons performing routine and complicated cataract surgery. These medications have been found to reduce pain, prevent intraoperative miosis, modulate postoperative inflammation, and reduce the incidence of cystoid macular edema (CME). Whether used alone, synergistically with steroids, or for specific high-risk eyes prone to the development of CME, the effectiveness of these medications is compelling. This review describes the potential preoperative, intraoperative, and postoperative uses of NSAIDs, including the potency, indications and treatment paradigms and adverse effects and contraindications. A thorough understanding of these issues will help surgeons maximize the therapeutic benefits of these agents and improve surgical outcomes.

FINANCIAL DISCLOSURE

Proprietary or commercial disclosures are listed after the references.

Testosterone Pathway Genetic Polymorphisms in Relation to Primary Open-Angle Glaucoma: An Analysis in Two Large Datasets

Purpose

Sex hormones may be associated with primary open-angle glaucoma (POAG), although the mechanisms are unclear. We previously observed that gene variants involved with estrogen metabolism were collectively associated with POAG in women but not men; here we assessed gene variants related to testosterone metabolism collectively and POAG risk.

Methods

We used two datasets: one from the United States (3853 cases and 33,480 controls) and another from Australia (1155 cases and 1992 controls). Both datasets contained densely called genotypes imputed to the 1000 Genomes reference panel. We used pathway- and gene-based approaches with Pathway Analysis by Randomization Incorporating Structure (PARIS) software to assess the overall association between a panel of single nucleotide polymorphisms (SNPs) in testosterone metabolism genes and POAG. In sex-stratified analyses, we evaluated POAG overall and POAG subtypes defined by maximum IOP (high-tension [HTG] or normal tension glaucoma [NTG]).

Results

In the US dataset, the SNP panel was not associated with POAG (permuted P = 0.77), although there was an association in the Australian sample (permuted P = 0.018). In both datasets, the SNP panel was associated with POAG in men (permuted P ≤ 0.033) and not women (permuted P ≥ 0.42), but in gene-based analyses, there was no consistency on the main genes responsible for these findings. In both datasets, the testosterone pathway association with HTG was significant (permuted P ≤ 0.011), but again, gene-based analyses showed no consistent driver gene associations.

Conclusions

Collectively, testosterone metabolism pathway SNPs were consistently associated with the high-tension subtype of POAG in two datasets.

West Indies Glaucoma Laser Study (WIGLS): 1. 12-Month Efficacy of Selective Laser Trabeculoplasty in Afro-Caribbeans With Glaucoma

PURPOSE

To characterize the 12-month intraocular pressure (IOP)-lowering efficacy of selective laser trabeculoplasty (SLT) as sole therapy for primary open-angle glaucoma (POAG) in an Afro-Caribbean population.

DESIGN

Stepped-wedge trial.

METHODS

Subjects in St. Lucia and Dominica with established POAG were randomized to prompt washout of IOP-lowering medications followed by SLT, 3-month delay followed by washout and SLT, or 6-month delay followed by washout and SLT. Baseline IOP was obtained on 2 different days after washout. Bilateral 360-degree SLT was performed in 1 session. Posttreatment assessments took place 1 hour, 1 week, and 3, 6, 9, and 12 months post-SLT. The main outcome measure was SLT success (defined as IOP ≤ target IOP in both eyes) at 12 months. Target IOP was a 20% or greater reduction in IOP from postwashout baseline.

RESULTS

Overall, 72 patients underwent SLT treatment. Mean IOP at enrollment was 15.4 ± 3.6 mm Hg in right eyes and 15.4 ± 3.6 mm Hg in left eyes, which rose to 21.0 ± 3.3 mm Hg and 20.9 ± 3.0 mm Hg, respectively, after washout. Mean IOP at 3, 6, 9, and 12 months ranged from 12.5 mm Hg to 14.5 mm Hg (29.7% to 39.5%; P < .0001 in each eye at each time point). The 12-month success rate was 78%. Transient photophobia and discomfort were common.

CONCLUSIONS

SLT monotherapy safely provides significant IOP reduction in Afro-Caribbean eyes with POAG. This treatment can play a significant role in preventing glaucoma vision loss and blindness in people of African descent living in resource-limited regions.

Genetic correlations between intraocular pressure, blood pressure and primary open-angle glaucoma: a multi-cohort analysis

Primary open-angle glaucoma (POAG) is the most common chronic optic neuropathy worldwide. Epidemiological studies show a robust positive relation between intraocular pressure (IOP) and POAG and modest positive association between IOP and blood pressure (BP), while the relation between BP and POAG is controversial. The International Glaucoma Genetics Consortium (n=27 558), the International Consortium on Blood Pressure (n=69 395), and the National Eye Institute Glaucoma Human Genetics Collaboration Heritable Overall Operational Database (n=37 333), represent genome-wide data sets for IOP, BP traits and POAG, respectively. We formed genome-wide significant variant panels for IOP and diastolic BP and found a strong relation with POAG (odds ratio and 95% confidence interval: 1.18 (1.14-1.21), P=1.8 × 10^-27) for the former trait but no association for the latter (P=0.93). Next, we used linkage disequilibrium (LD) score regression, to provide genome-wide estimates of correlation between traits without the need for additional phenotyping. We also compared our genome-wide estimate of heritability between IOP and BP to an estimate based solely on direct measures of these traits in the Erasmus Rucphen Family (ERF; n=2519) study using Sequential Oligogenic Linkage Analysis Routines (SOLAR). LD score regression revealed high genetic correlation between IOP and POAG (48.5%, P=2.1 × 10^-5); however, genetic correlation between IOP and diastolic BP (P=0.86) and between diastolic BP and POAG (P=0.42) were negligible. Using SOLAR in the ERF study, we confirmed the minimal heritability between IOP and diastolic BP (P=0.63). Overall, IOP shares genetic basis with POAG, whereas BP has limited shared genetic correlation with IOP or POAG.

Age at natural menopause genetic risk score in relation to age at natural menopause and primary open-angle glaucoma in a US-based sample

OBJECTIVE

Several attributes of female reproductive history, including age at natural menopause (ANM), have been related to primary open-angle glaucoma (POAG). We assembled 18 previously reported common genetic variants that predict ANM to determine their association with ANM or POAG.

METHODS

Using data from the Nurses' Health Study (7,143 women), we validated the ANM weighted genetic risk score in relation to self-reported ANM. Subsequently, to assess the relation with POAG, we used data from 2,160 female POAG cases and 29,110 controls in the National Eye Institute Glaucoma Human Genetics Collaboration Heritable Overall Operational Database (NEIGHBORHOOD), which consists of 8 datasets with imputed genotypes to 5.6+ million markers. Associations with POAG were assessed in each dataset, and site-specific results were meta-analyzed using the inverse weighted variance method.

RESULTS

The genetic risk score was associated with self-reported ANM (P = 2.2 × 10) and predicted 4.8% of the variance in ANM. The ANM genetic risk score was not associated with POAG (Odds Ratio (OR) = 1.002; 95% Confidence Interval (CI): 0.998, 1.007; P = 0.28). No single genetic variant in the panel achieved nominal association with POAG (P ≥0.20). Compared to the middle 80 percent, there was also no association with the lowest 10 percentile or highest 90 percentile of genetic risk score with POAG (OR = 0.75; 95% CI: 0.47, 1.21; P = 0.23 and OR = 1.10; 95% CI: 0.72, 1.69; P = 0.65, respectively).

CONCLUSIONS

A genetic risk score predicting 4.8% of ANM variation was not related to POAG; thus, genetic determinants of ANM are unlikely to explain the previously reported association between the two phenotypes.

Assessing the Association of Mitochondrial Genetic Variation With Primary Open-Angle Glaucoma Using Gene-Set Analyses

Purpose

Recent studies indicate that mitochondrial proteins may contribute to the pathogenesis of primary open-angle glaucoma (POAG). In this study, we examined the association between POAG and common variations in gene-encoding mitochondrial proteins.

Methods

We examined genetic data from 3430 POAG cases and 3108 controls derived from the combination of the GLAUGEN and NEIGHBOR studies. We constructed biological-system coherent mitochondrial nuclear-encoded protein gene-sets by intersecting the MitoCarta database with the Kyoto Encyclopedia of Genes and Genomes (KEGG) database. We examined the mitochondrial gene-sets for association with POAG and with normal-tension glaucoma (NTG) and high-tension glaucoma (HTG) subsets using Pathway Analysis by Randomization Incorporating Structure.

Results

We identified 22 KEGG pathways with significant mitochondrial protein-encoding gene enrichment, belonging to six general biological classes. Among the pathway classes, mitochondrial lipid metabolism was associated with POAG overall (P = 0.013) and with NTG (P = 0.0006), and mitochondrial carbohydrate metabolism was associated with NTG (P = 0.030). Examining the individual KEGG pathway mitochondrial gene-sets, fatty acid elongation and synthesis and degradation of ketone bodies, both lipid metabolism pathways, were significantly associated with POAG (P = 0.005 and P = 0.002, respectively) and NTG (P = 0.0004 and P < 0.0001, respectively). Butanoate metabolism, a carbohydrate metabolism pathway, was significantly associated with POAG (P = 0.004), NTG (P = 0.001), and HTG (P = 0.010).

Conclusions

We present an effective approach for assessing the contributions of mitochondrial genetic variation to open-angle glaucoma. Our findings support a role for mitochondria in POAG pathogenesis and specifically point to lipid and carbohydrate metabolism pathways as being important.

A Randomized Trial of Fixed-Dose Combination Brinzolamide 1%/Brimonidine 0.2% as Adjunctive Therapy to Travoprost 0.004

PURPOSE

To evaluate the safety and efficacy of adding fixed-combination brinzolamide 1%/brimonidine 0.2% (BBFC) as adjunctive therapy to travoprost 0.004% (TRAV) in patients with open-angle glaucoma or ocular hypertension.

DESIGN

Multicenter, randomized, double-masked, parallel-group phase 4 clinical trial.

METHODS

setting: Multicenter; 32 sites in the United States.

PATIENT POPULATION

Total of 233 patients with open-angle glaucoma or ocular hypertension and with mean intraocular pressure (IOP) ≥21 mm Hg and <32 mm Hg while receiving once-daily TRAV monotherapy.

INTERVENTION

Masked BBFC or vehicle (3 times daily) adjunctive to TRAV for 6 weeks.

MAIN OUTCOME MEASURE

Mean diurnal IOP averaged over 8 AM, 10 AM, 3 PM, and 5 PM time points at week 6. Superiority of BBFC+TRAV over vehicle+TRAV was based on statistical significance of a treatment difference favoring BBFC+TRAV.

RESULTS

Mean diurnal IOP at week 6 (least squares mean ± standard error) was 17.6 ± 0.4 mm Hg and 20.7 ± 0.4 mm Hg in the BBFC+TRAV and vehicle+TRAV groups, respectively (between-group difference, -3.2 ± 0.5 mm Hg; P < .0001). Superiority of BBFC+TRAV over vehicle+TRAV was established. Mean and percent diurnal IOP change from baseline were significantly greater with BBFC+TRAV compared with vehicle+TRAV (P < .0001 for both). Conjunctival hyperemia was the most common treatment-related adverse event in either group (BBFC+TRAV, 12.8%; vehicle+TRAV, 6.0%).

CONCLUSIONS

Adjunctive treatment with BBFC added to TRAV resulted in lower mean diurnal IOP after 6 weeks of treatment compared with vehicle added to TRAV; this difference was both statistically and clinically significant.

Axial Globe Position Measurement: A Prospective Multicenter Study by the International Thyroid Eye Disease Society

PURPOSE

Identify a reproducible measure of axial globe position (AGP) for multicenter studies on patients with thyroid eye disease (TED).

METHODS

This is a prospective, international, multicenter, observational study in which 3 types of AGP evaluation were examined: radiologic, clinical, and photographic. In this study, CT was the modality to which all other methods were compared. CT AGP was measured from an orthogonal line between the anterior lateral orbital rims to the cornea. All CT measurements were made at a single institution by 3 individual clinicians. Clinical evaluation was performed with exophthalmometry. Three clinicians from each clinical site assessed AGP with 3 different exophthalmometers and horizontal palpebral width using a ruler. Each physician made 3 separate measurements with each type of exophthalmometer not in succession. All photographic measurements were made at a single institution. AGP was measured from lateral photographs in which a standard marker was placed at the anterior lateral orbital rim. Horizontal and vertical palpebral fissure were measured from frontal photographs. Three trained readers measured 3 separate times not in succession. Exophthalmometry and photography method validity was assessed by agreement with CT (mean differences calculation, intraclass correlation coefficients [ICCs], Bland-Altman figures). Correlation between palpebral fissure and CT AGP was assessed with Pearson correlation. Intraclinician and interclinician reliability was evaluated using ICCs.

RESULTS

Sixty-eight patients from 7 centers participated. CT mean AGP was 21.37 mm (15.96-28.90 mm) right and 21.22 mm (15.87-28.70 mm) left (ICC 0.996 and 0.995). Exophthalmometry AGP fell between 18 mm and 25 mm. Intraclinician agreement across exophthalmometers was ideal (ICC 0.948-0.983). Agreement between clinicians was greater than 0.85 for all upright exophthalmometry measurements. Photographic mean AGP was 20.47 mm (10.92-30.88 mm) right and 20.30 mm (8.61-28.72 mm) left. Intrareader and interreader agreement was ideal (ICC 0.991-0.989). All exophthalmometers' mean differences from CT ranged between -0.06 mm (±1.36 mm) and 0.54 mm (±1.61 mm); 95% confidence interval fell within 1 mm. Magnitude of AGP did not affect exophthalmometry validity. Oculus best estimated CT AGP but differences from other exophthalmometers were not clinically meaningful in upright measurements. Photographic AGP (right ICC = 0.575, left ICC = 0.355) and palpebral fissure do not agree with CT.

CONCLUSIONS

Upright clinical exophthalmometry accurately estimates CT AGP in TED. AGP measurement was reliably reproduced by the same clinician and between clinicians at multiple institutions using the protocol in this study. These findings allow reliable measurement of AGP that will be of considerable value in future outcome studies.

Repeatability of selective laser trabeculoplasty

PURPOSE

To determine the intraocular pressure (IOP)-lowering efficacy of repeat 360° selective laser trabeculoplasty (SLT) in patients with open-angle glaucoma having undergone prior successful 360° SLT.

METHODS

A retrospective chart review of 38 eyes of 38 patients with open-angle glaucoma (primary, pseudoexfoliation or pigmentary glaucoma) uncontrolled on medical therapy who had undergone two successive 360° SLT treatments, in whom first SLT was deemed clinically successful through a minimum of 6 months follow-up and who were followed for a minimum of 30 days after second SLT. Mean IOP at each postoperative time point (1, 3, 6, 12, 18 and 24 months) was compared with baseline using paired t tests. IOP changes after initial and repeat SLT were evaluated separately.

RESULTS

Mean (SD) baseline IOP before initial SLT was 21.6 (4.8) mm Hg. Mean IOP following initial SLT was significantly below baseline through 24 months of follow-up, with mean IOP at months 1-24 ranging from 15.9 to 18.6 mm Hg. Mean baseline IOP before repeat SLT was 19.1 (3.9) mm Hg, with a significant reduction in IOP from baseline through 24 months follow-up with mean IOP ranging from 14.7 to 17.0 mm Hg. Kaplan-Meier survival analysis showed longer median survival time for repeat SLT compared with initial SLT. No safety issues were observed with repeat SLT.

CONCLUSIONS

Repeat SLT can restore IOP control in eyes with open-angle glaucoma that have previously undergone successful initial SLT. Repeat SLT achieves comparable absolute level of IOP control achieved by initial SLT.

Genome-wide association analysis identifies TXNRD2, ATXN2 and FOXC1 as susceptibility loci for primary open-angle glaucoma

Primary open angle glaucoma (POAG) is a leading cause of blindness world-wide. To identify new susceptibility loci, we meta-analyzed GWAS results from 8 independent studies from the United States (3,853 cases and 33,480 controls) and investigated the most significant SNPs in two Australian studies (1,252 cases and 2,592 controls), 3 European studies (875 cases and 4,107 controls) and a Singaporean Chinese study (1,037 cases and 2,543 controls). A meta-analysis of top SNPs identified three novel loci: rs35934224[T] within TXNRD2 (odds ratio (OR) = 0.78, P = 4.05×10⁻¹¹ encoding a mitochondrial protein required for redox homeostasis; rs7137828[T] within ATXN2 (OR = 1.17, P = 8.73×10⁻¹⁰), and rs2745572[A] upstream of FOXC1 (OR = 1.17, P = 1.76×10⁻¹⁰). Using RT-PCR and immunohistochemistry, we show TXNRD2 and ATXN2 expression in retinal ganglion cells and the optic nerve head. These results identify new pathways underlying POAG susceptibility and suggest novel targets for preventative therapies.

Latanoprostene Bunod, a Dual-acting Nitric Oxide Donating Prostaglandin Analog for Lowering of Intraocular Pressure

Current topical treatments for glaucoma have limited efficacy in lowering intraocular pressure (IOP) and/or can produce side effects and tolerability problems. At present, IOP remains the only known modifiable risk factor to delay the progression of glaucoma. The novel IOP-lowering treatment latanoprostene bunod (LBN) is a nitric oxide (NO)-donating prostaglandin F2αanalog that is rapidly metabolized in situ to latanoprost acid and butanediol mononitrate, an NO-donating moiety. LBN has a dual action in that it enhances aqueous humor outflow via both the uveoscleral and trabecular meshwork pathways. It is undergoing regulatory review by the Food and Drug Administration (FDA) for the reduction of IOP in patients with open-angle glaucoma (OAG) or ocular hypertension (OHT). In the dose-ranging VOYAGER study, LBN 0.024%, the lower of the most effective concentrations evaluated, demonstrated significantly greater IOP lowering and comparable side effects compared with latanoprost 0.005%. The recent APOLLO phase III clinical study (n=420) found LBN 0.024% demonstrated significantly greater reductions in IOP than timolol 0.5% in patients with OAG or OHT at various time points over 3 months. The same study found the proportion of patients with IOP ≤18 mmHg was significantly greater with LBN 0.024% than with timolol 0.5%. In the LUNAR study (n=420), LBN 0.024% was non-inferior to timolol 0.5% over 3 months’ treatment. LBN treatment also resulted in significantly greater IOP lowering than timolol at all time-points with the exception of the first post-baseline assessment. In JUPITER, a study of 130 subjects with OAG or OHT, LBN 0.024% was safe and well tolerated when used for up to a year, and provided significant and sustained IOP reduction. Further, in CONSTELLATION, a study of 25 patients with OHT or OAG, IOP lowering with LBN 0.024% was consistently lower than baseline during both the diurnal/wake and nocturnal/sleep periods whereas timolol 0.5% reduced IOP only during the diurnal period. In addition, LBN 0.024% treatment resulted in a significantly increased diurnal ocular perfusion pressure versus baseline and nocturnal ocular perfusion pressure versus timolol 0.05%. Similarly, in KRONUS, a single-arm, single-center, openlabel study of 24 healthy Japanese subjects, LBN 0.024% significantly lowered mean IOP over a 24-hour period. Across these studies, LBN has demonstrated a favorable safely profile and good ocular tolerability. It is hypothesized that LBN’s dual action on the outflow pathways accounts for the improved efficacy when compared with latanoprost and timolol.

Hypothesis-independent pathway analysis implicates GABA and acetyl-CoA metabolism in primary open-angle glaucoma and normal-pressure glaucoma

Primary open-angle glaucoma (POAG) is a leading cause of blindness worldwide. Using genome-wide association single-nucleotide polymorphism data from the Glaucoma Genes and Environment study and National Eye Institute Glaucoma Human Genetics Collaboration comprising 3,108 cases and 3,430 controls, we assessed biologic pathways as annotated in the KEGG database for association with risk of POAG. After correction for genic overlap among pathways, we found 4 pathways, butanoate metabolism (hsa00650), hematopoietic cell lineage (hsa04640), lysine degradation (hsa00310) and basal transcription factors (hsa03022) related to POAG with permuted p < 0.001. In addition, the human leukocyte antigen (HLA) gene family was significantly associated with POAG (p < 0.001). In the POAG subset with normal-pressure glaucoma (NPG), the butanoate metabolism pathway was also significantly associated (p < 0.001) as well as the MAPK and Hedgehog signaling pathways (hsa04010 and hsa04340), glycosaminoglycan biosynthesis-heparan sulfate pathway (hsa00534) and the phenylalanine, tyrosine and tryptophan biosynthesis pathway (hsa0400). The butanoate metabolism pathway overall, and specifically the aspects of the pathway that contribute to GABA and acetyl-CoA metabolism, was the only pathway significantly associated with both POAG and NPG. Collectively these results implicate GABA and acetyl-CoA metabolism in glaucoma pathogenesis, and suggest new potential therapeutic targets.

Association of CAV1/CAV2 genomic variants with primary open-angle glaucoma overall and by gender and pattern of visual field loss

PURPOSE

The CAV1/CAV2 (caveolin 1 and caveolin 2) genomic region previously was associated with primary open-angle glaucoma (POAG), although replication among independent studies has been variable. The aim of this study was to assess the association between CAV1/CAV2 single nucleotide polymorphisms (SNPs) and POAG in a large case-control dataset and to explore associations by gender and pattern of visual field (VF) loss further.

DESIGN

Case-control study.

PARTICIPANTS

We analyzed 2 large POAG data sets: the Glaucoma Genes and Environment (GLAUGEN) study (976 cases, 1140 controls) and the National Eye Institute Glaucoma Human Genetics Collaboration (NEIGHBOR) consortium (2132 cases, 2290 controls).

METHODS

We studied the association between 70 SNPs located within the CAV1/CAV2 genomic region in the GLAUGEN and NEIGHBOR studies, both genotyped on the Illumina Human 660WQuadv1C BeadChip array and imputed with the Markov Chain Haplotyping algorithm using the HapMap 3 reference panel. We used logistic regression models of POAG in the overall population and separated by gender, as well as by POAG subtypes defined by type of VF defect (peripheral or paracentral). Results from GLAUGEN and NEIGHBOR were meta-analyzed, and a Bonferroni-corrected significance level of 7.7 × 10(-4) was used to account for multiple comparisons.

MAIN OUTCOME MEASURES

Overall POAG, overall POAG by gender, and POAG subtypes defined by pattern of early VF loss.

RESULTS

We found significant associations between 10 CAV1/CAV2 SNPs and POAG (top SNP, rs4236601; pooled P = 2.61 × 10(-7)). Of these, 9 were significant only in women (top SNP, rs4236601; pooled P = 1.59 × 10(-5)). Five of the 10 CAV1/CAV2 SNPs were associated with POAG with early paracentral VF (top SNP, rs17588172; pooled P = 1.07 × 10(-4)), and none of the 10 were associated with POAG with peripheral VF loss only or POAG among men.

CONCLUSIONS

CAV1/CAV2 SNPs were associated significantly with POAG overall, particularly among women. Furthermore, we found an association between CAV1/CAV2 SNPs and POAG with paracentral VF defects. These data support a role for caveolin 1, caveolin 2, or both in POAG and suggest that the caveolins particularly may affect POAG pathogenesis in women and in patients with early paracentral VF defects.

Estrogen pathway polymorphisms in relation to primary open angle glaucoma: an analysis accounting for gender from the United States

PURPOSE

Circulating estrogen levels are relevant in glaucoma phenotypic traits. We assessed the association between an estrogen metabolism single nucleotide polymorphism (SNP) panel in relation to primary open angle glaucoma (POAG), accounting for gender.

METHODS

We included 3,108 POAG cases and 3,430 controls of both genders from the Glaucoma Genes and Environment (GLAUGEN) study and the National Eye Institute Glaucoma Human Genetics Collaboration (NEIGHBOR) consortium genotyped on the Illumina 660W-Quad platform. We assessed the relation between the SNP panels representative of estrogen metabolism and POAG using pathway- and gene-based approaches with the Pathway Analysis by Randomization Incorporating Structure (PARIS) software. PARIS executes a permutation algorithm to assess statistical significance relative to the pathways and genes of comparable genetic architecture. These analyses were performed using the meta-analyzed results from the GLAUGEN and NEIGHBOR data sets. We evaluated POAG overall as well as two subtypes of POAG defined as intraocular pressure (IOP) ≥22 mmHg (high-pressure glaucoma [HPG]) or IOP <22 mmHg (normal pressure glaucoma [NPG]) at diagnosis. We conducted these analyses for each gender separately and then jointly in men and women.

RESULTS

Among women, the estrogen SNP pathway was associated with POAG overall (permuted p=0.006) and HPG (permuted p<0.001) but not NPG (permuted p=0.09). Interestingly, there was no relation between the estrogen SNP pathway and POAG when men were considered alone (permuted p>0.99). Among women, gene-based analyses revealed that the catechol-O-methyltransferase gene showed strong associations with HTG (permuted gene p≤0.001) and NPG (permuted gene p=0.01).

CONCLUSIONS

The estrogen SNP pathway was associated with POAG among women.

Six-month results from a Phase III randomized trial of fixed-combination brinzolamide 1% + brimonidine 0.2% versus brinzolamide or brimonidine monotherapy in glaucoma or ocular hypertension

Background

The objective of this study was to examine the safety and intraocular pressure (IOP)-lowering efficacy of a fixed combination of brinzolamide 1% + brimonidine 0.2% (BBFC) after six months of treatment in patients with open-angle glaucoma or ocular hypertension.

Methods

This was a randomized, multicenter, double-masked, three-month, three-arm contribution-of-elements study with a three-month safety extension. Patients were randomly assigned 1:1:1 to treatment with BBFC, brinzolamide 1%, or brimonidine 0.2% after a washout period. Patients dosed their study medications three times daily at 8 am, 3 pm, and 10 pm for six months. Patients returned for visits at two weeks, six weeks, three months, and six months. IOP measurements were used to assess efficacy. Safety assessments were adverse events, corrected distance visual acuity, slit-lamp biomicroscopy, pachymetry, perimetry, fundus parameters, and cardiac parameters.

Results

A total of 690 patients were randomized. Six-month mean IOP values were similar to those at three months, when the mean IOP in patients treated with BBFC was significantly lower than that of either monotherapy group. A total of 175 patients experienced at least one treatment-related adverse event (BBFC, 33.0%; brinzolamide, 18.8%; brimonidine, 24.7%), eight of which were severe, and five resulted in discontinuation. Seventy-seven patients discontinued participation due to treatment-related adverse events (BBFC, 17.2%; brinzolamide, 2.1%; brimonidine, 14.5%). There were 21 serious adverse events (n = 7 in each group), none of which was related to treatment. Resting mean pulse and blood pressure with BBFC were similar to those with brimonidine, demonstrating modest, clinically insignificant decreases. No new or increased risks were identified with use of BBFC relative to either monotherapy.

Conclusion

This study showed that, after six months of treatment, the safety profile of BBFC was similar to that of its individual components and its IOP-lowering activity was similar to its efficacy at three months, when it was superior to both brinzolamide 1% alone and brimonidine 0.2% alone.

Fixed-combination brinzolamide 1%/brimonidine 0.2% vs monotherapy with brinzolamide or brimonidine in patients with open-angle glaucoma or ocular hypertension: results of a pooled analysis of two phase 3 studies

Purpose

To describe pooled efficacy and safety data from two phase 3 studies comparing brinzolamide 1%/brimonidine 0.2% fixed combination (BBFC) with its component medications, brinzolamide and brimonidine, in patients with open-angle glaucoma or ocular hypertension.

Methods

Data were pooled from two nearly identical clinical trials comparing BBFC with its component medications, each given three times daily. The 3-month efficacy outcome was mean intraocular pressure (IOP) at 0800, 1000, 1500, and 1700 hours. Safety outcomes included adverse events (AEs), best-corrected visual acuity, examination of ocular structures, pachymetry, perimetry, and vital signs.

Results

A total of 1350 patients were enrolled and included in this analysis (BBFC, n=437; brinzolamide, n=458; brimonidine, n=455). Baseline mean IOP levels were similar among the three treatment groups. At 3 months, mean IOP of the BBFC group was significantly lower than that of either monotherapy group (P<0.0001) at all the four time points. A total of 272 patients (20.1%) experienced at least one treatment-related AE (BBFC, 24.6% brinzolamide, 18.7% brimonidine, 17.4%), the majority of which were ocular AEs. One serious AE, moderate intensity chest pain, was considered related to brinzolamide treatment and resulted in study discontinuation.

Conclusions

This analysis strengthens the conclusions drawn from the two individual phase 3 studies showing that, in patients with open-angle glaucoma or ocular hypertension, BBFC had significantly superior IOP-lowering activity compared with either brinzolamide or brimonidine alone and a safety profile consistent with that of its individual components.

Phase 3 randomized 3-month trial with an ongoing 3-month safety extension of fixed-combination brinzolamide 1%/brimonidine 0.2%

PURPOSE

This study compared the intraocular pressure (IOP)-lowering efficacy of fixed-combination brinzolamide 1%/brimonidine 0.2% (BBFC) with that of its component medications, brinzolamide and brimonidine, in patients with open-angle glaucoma or ocular hypertension.

PATIENTS AND METHODS

In this phase 3, multicenter, double-masked, parallel-group, 3-month study with a 3-month safety extension, eligible patients were randomized 1:1:1 to treatment with BBFC, brinzolamide, or brimonidine thrice daily after a washout period, during which any IOP-lowering medications were discontinued. The primary objectives of this study were to determine whether the IOP-lowering efficacy of BBFC was superior to that of brinzolamide alone and, separately, of brimonidine alone. IOP was assessed at 8:00 AM, 10:00 AM, 3:00 PM, and 5:00 PM at 2 weeks, 6 weeks, and 3 months after study drug initiation.

RESULTS

A total of 690 patients were enrolled in the study, and 615 completed the 3-month visit. Baseline mean IOP levels were similar among the 3 treatment groups at each of the 4 time points assessed. At the 3-month primary endpoint, mean IOP of the BBFC group was significantly lower than that of either the brinzolamide group or the brimonidine group (P≤0.005) across all time points. At the 2- and 6-week supportive endpoints, mean IOP of the BBFC group was significantly lower at all time points than the mean IOP of either the brinzolamide group (P≤0.01) or the brimonidine group (P<0.0001). A total of 143 patients experienced at least 1 treatment-related adverse event (AE; BBFC group, n=58, 26.2%; brinzolamide group, n=44, 18.8%; brimonidine group, n=41, 17.4%), the majority of which were ocular AEs.

CONCLUSIONS

This study demonstrated that BBFC has significantly superior IOP-lowering activity compared with either brinzolamide 1% or brimonidine 0.2% in patients with open-angle glaucoma or ocular hypertension while providing a safety profile which is consistent with that of the individual components.

CDKN2B-AS1 genotype-glaucoma feature correlations in primary open-angle glaucoma patients from the United States

PURPOSE

To assess the association between single nucleotide polymorphisms (SNPs) of the gene region containing cyclin-dependent kinase inhibitor 2B antisense noncoding RNA (CDKN2B-AS1) and glaucoma features among primary open-angle glaucoma (POAG) patients.

DESIGN

Retrospective observational case series.

METHODS

We studied associations between 10 CDKN2B-AS1 SNPs and glaucoma features among 976 POAG cases from the Glaucoma Genes and Environment (GLAUGEN) study and 1971 cases from the National Eye Institute Glaucoma Human Genetics Collaboration (NEIGHBOR) consortium. For each patient, we chose the feature from the eye with the higher value. We created cohort-specific multivariable models for glaucoma features and then meta-analyzed the results.

RESULTS

For 9 of the 10 protective CDKN2B-AS1 SNPs with minor alleles associated with reduced disease risk (eg, the G allele at rs2157719), POAG patients carrying these minor alleles had smaller cup-to-disc ratio (0.05 units smaller per G allele at diagnosis; 95% CI: -0.08, -0.03; P = 6.23E-05) despite having higher intraocular pressure (IOP) (0.70 mm Hg higher per G allele at DNA collection; 95% CI: 0.40, 1.00; P = 5.45E-06). For the 1 adverse rs3217992 SNP with minor allele A associated with increased disease risk, POAG patients with A alleles had larger cup-to-disc ratio (0.05 units larger per A allele at diagnosis; 95% CI: 0.02, 0.07; P = 4.74E-04) despite having lower IOP (-0.57 mm Hg per A allele at DNA collection; 95% CI: -0.84, -0.29; P = 6.55E-05).

CONCLUSION

Alleles of CDKN2B-AS1 SNPs, which influence risk of developing POAG, also modulate optic nerve degeneration among POAG patients, underscoring the role of CDKN2B-AS1 in POAG.

Overview of the [corrected] travoprost /timolol BAK-free fixed combination

INTRODUCTION

Glaucoma is the second leading cause of blindness globally, representing a significant public health concern. More than 60 million people are affected by glaucoma worldwide; as this population ages, the number is expected to increase. Glaucoma is a collection of heterogeneous diseases sharing common clinical characteristics. The goal of treatment is to prevent significant visual dysfunction through reduction of intraocular pressure (IOP).

AREAS COVERED

This is a review of the current literature about combination therapeutic regimens for the reduction of IOP, focusing on the risk : benefit profile of a fixed-combination therapy using travoprost and timolol.

EXPERT OPINION

Since the debut of prostaglandin analogues in the 1990s, only modest innovation has occurred in glaucoma pharmacology. A growing body of research has established that the preservative benzalkonium chloride (BAK) might not be the benign contributor expected of excipient ingredients. Thus, BAK-free treatments were developed, with the goal of IOP reduction without furthering ocular surface disease symptoms. The BAK-free travoprost/timolol combination represents an important addition to glaucoma medication options and may fill an unmet need in this therapeutic arena.

Asymmetry of 24-hour intraocular pressure reduction by topical ocular hypotensive medications in fellow eyes

PURPOSE

A core assumption for the 1-eye therapeutic trial of ocular hypotensive medications is the symmetrical reduction of intraocular pressure (IOP) in paired eyes. This assumption was evaluated for 24-hour IOP reduction in patients who underwent monotherapy or adjunctive therapy.

DESIGN

Database study.

PARTICIPANTS

Patients 41 to 79 years of age with primary open-angle glaucoma or ocular hypertension.

METHODS

Twenty-four-hour IOP data from the paired eyes of patients undergoing bilateral monotherapy (n = 66) of latanoprost, travoprost, timolol, or brimonidine or bilateral adjunctive therapy (n = 52) with brinzolamide or timolol added to latanoprost monotherapy were analyzed retrospectively. Measurements of IOP were obtained every 2 hours in a sleep laboratory before and after at least 4-week drug treatments. Strengths of association for single-pair IOP reductions and average IOP reductions in the paired eyes during the office-hour, diurnal, nocturnal, and 24-hour periods and in different body positions were analyzed.

MAIN OUTCOME MEASURES

Variance for the difference, percentage distribution of large absolute difference, and coefficient of determination (r(2)) in the paired IOP reductions.

RESULTS

The standard deviations for the differences in single-pair IOP reductions from the means were larger than 2.5 mmHg for all periods and body positions under monotherapy and adjunctive therapy. Absolute differences in single-pair IOP reductions of the cutoff thresholds of 3 and 2 mmHg or more occurred in more than 20% and 36% cases, respectively. Corresponding coefficients of determination were 0.240 to 0.374 with monotherapy and 0.215 to 0.381 with adjunctive therapy. When the average differences in the paired IOP reductions were analyzed for a specific period and posture, the standard deviations for the differences in the paired IOP reductions and the percentage distributions of large absolute differences were reduced, and most coefficients of determination were improved.

CONCLUSIONS

There is only a weak association between the right- and left-eye responses to IOP-lowering monotherapy or adjunctive therapy during a 24-hour period when single-pair IOP data are considered. Considering the averages of multiple paired IOP responses can improve the strength of the association.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Short-term repeatability of diurnal intraocular pressure patterns in glaucomatous individuals

PURPOSE

To evaluate the short-term repeatability of diurnal intraocular pressure (IOP) patterns in eyes with primary open-angle glaucoma (POAG).

DESIGN

Observational cohort study.

PARTICIPANTS

Forty-seven subjects with treated POAG.

METHODS

Subjects underwent assessment of IOP using Goldmann tonometry every 2 hours from 0800 to 2000 on 2 visits 1 week apart. Intervisit agreement of IOP by time point and of IOP change between time points was assessed using intraclass correlation coefficients (ICCs).

MAIN OUTCOME MEASURES

Diurnal IOP patterns.

RESULTS

Between-visit agreement of IOP values at each time point was generally fair to good, with ICCs ranging from 0.45 to 0.71 in right eyes and from 0.51 to 0.71 in left eyes. Between-visit agreement of IOP change over time periods between time points was uniformly poor, with ICCs ranging from -0.08 to 0.38 in right eyes and from -0.11 to 0.36 in left eyes.

CONCLUSIONS

Treated POAG patients do not manifest a repeatable diurnal IOP pattern from day to day when measured by Goldmann tonometry. Measurement of single-day IOP variation poorly characterized short-term IOP variation.

Primary open angle glaucoma in a Caucasian population is associated with the p53 codon 72 polymorphism

PURPOSE

Apoptosis has been implicated as the mechanism for retinal ganglion cell death in primary open-angle glaucoma (POAG), a complex neurodegenerative disease. There have been inconsistent reports regarding increased risk of POAG and a polymorphism (Arg72Pro) within the tumor suppressor gene, p53. The goal of this study was to examine the role of this polymorphism in susceptibility to POAG in a Caucasian population from the United States.

METHODS

We generated genotypes in 191 unrelated Caucasian POAG patients and 167 unrelated Caucasian controls for the following polymorphisms within p53: rs1042522 (Arg72Pro), rs17878362 (16 bp Ins/Del), and rs1800371 (Pro47Ser) by PCR amplification followed by restriction digestion and sequence analysis.

RESULTS

There was a significant difference in genotypic frequencies for rs1042522 (Arg72Pro) between POAG patients and controls (chi(2)= 9.56, p=0.008). Individuals who were homozygous for the arginine allele have a 1.9 fold significantly increased risk of developing glaucoma (95%CI: 1.16-2.82, p=0.01). Interestingly, we found that the frequency of the arginine allele was even higher in the normal-tension glaucoma (NTG) subtype compared to high-tension POAG (0.81 versus 0.76).

CONCLUSIONS

Our preliminary results indicate that the arginine variant of rs1042522 within p53 is associated with increased risk of POAG. This variant has increased apoptotic potential, thus the retinal ganglion cells in carriers of the arginine allele may have greater susceptibility to apoptosis.

Anterior juxtascleral delivery of anecortave acetate in eyes with primary open-angle glaucoma: a pilot investigation

PURPOSE

To describe the intraocular pressure (IOP)-lowering effects in eyes with open-angle glaucoma (OAG) after treatment with an anterior juxtascleral depot of anecortave acetate.

DESIGN

Prospective, interventional case series.

METHODS

Seven eyes of six subjects with OAG, with uncontrolled IOP while being administered one or more topical medications, received 24 mg anecortave acetate delivered by anterior juxtascleral depot. IOP was assessed at baseline and regularly after treatment for up to 24 months.

RESULTS

Mean IOP before anecortave acetate treatment was 31.3 +/- 11.3 mm Hg and dropped by 9.5 +/- 4.5 mm Hg (32.7% +/- 16.8%) within one week after treatment. This IOP reduction was sustained through six months (8.4 +/- 5.4 mm Hg [29.6% +/- 12.4%]) and 12 months (9.5 +/- 5.7 mm Hg [34.0% +/- 15.9%]) after a single anecortave acetate treatment. The injection process was well tolerated, and no eyes experienced any injection-related or drug-related serious adverse events.

CONCLUSIONS

Both the anterior juxtascleral depot of a drug and anecortave acetate may be promising candidates for IOP reduction in eyes with OAG. Additional studies are required to establish better their efficacy and safety, optimal dosing frequency, mechanism of action, and potential additivity to other IOP-lowering therapies.

Use of fixed-dose combination drugs for the treatment of glaucoma

Glaucoma is a leading cause of irreversible visual loss. This potentially blinding disease is a progressive optic neuropathy associated with elevated intraocular pressure (IOP). Initial therapy for glaucoma typically consists of topical medications or laser treatment to lower IOP. Frequently, more than one medication is required to achieve adequate control of IOP. However, more medications means more bottles and greater complexity for the patient. There are several potential benefits of fixed combination medications compared with using the individual components separately. These include a reduction in the total number of drops and preservative instilled per day, cost savings, improved tolerability and compliance and avoiding the washout effect resulting from rapid-sequence instillation of multiple drops. Attempts to develop effective fixed combinations of glaucoma medications date back several decades. In recent years, fixed combinations of commonly paired drugs have been approved by various regulatory bodies in different countries and have gained wide acceptance. Current commercially available, fixed combination drugs include the topical beta-adrenoceptor antagonist timolol 0.5% combined with a prostaglandin, a topical carbonic anhydrase inhibitor or an alpha-adrenoceptor agonist. Although there is no uniformity among registration trial designs, most published literature compares the efficacy of the fixed combination to the individual components and to concomitant use of both components. Various factors inherent to study design such as medication run-in, washout periods and peak and trough effects have to be taken into consideration when analysing the demonstrated efficacy of fixed combinations. Fixed combination treatments offer effective IOP control while reducing the washout effect and exposure to preservatives. They are also convenient. However, fixed combinations also remove the possibility of titrating the individual components both in terms of concentration and timing of administration. In addition, fixed combinations might not always provide the same efficacy as proper use of the individual components. The clinician must make individualised assessments when weighing the convenience of these medications against their limitations for specific patients.

Comparison of Digital and Film Stereo Photography of the Optic Nerve in the Evaluation of Patients with Glaucoma

The aim of this study was to validate a digital simultaneous stereo photography system against film in the assessment of optic nerve head features in patients with glaucoma. Fifteen digital and 15 corresponding film simultaneous stereo photographs (SSP) of the optic nerve from patients with glaucoma were graded by two glaucoma specialists. Assessed parameters included the vertical and horizontal cup-to-disc ratios (VCD and HCD, respectively), and the image quality score (1 = worse, 5 = best) for each image. Digital and film SSP were presented in random order, two times to each grader. A total of 60 evaluations (30 digital and 30 film) per grader were collected. A Nidek 3-Dx simultaneous stereo disc camera (Gamagori, Japan) was used with both a standard 35-mm-film camera back, and with a 6.1 mega pixel camera (Nikon D1x, Tokyo, Japan) for capture of digital images. All digital images were stored on a computer and reviewed using the Navis Screener software (proprietary software from Nidek). Digital image pairs were evaluated directly on an ADVAN 27-inch Liquid Crystal Display computer monitor (Taipei, Taiwan) with resolution comparable to that of the digital camera, using the screen-vu stereo viewer held at a fixed angle to the monitor. Film image pairs were evaluated using a Pentax stereo slide viewer (Asahi Optical Co., Tokyo, Japan) illuminated by a light box over a neutral density filter to match the luminance between the computer screen and the light box. The mean difference between digital and film was near zero for all three evaluated outcomes (VCD, HCD, and quality score), and there was no significant grader effect for any of the outcomes. Digital images correlated well with film for SSP of the optic nerve in glaucoma.

Symmetry of fellow-eye intraocular pressure responses to topical glaucoma medications

PURPOSE

One assumption of the uniocular drug trial in glaucoma management is that fellow-eye pairs exhibit symmetric intraocular pressure (IOP) responses when both eyes are treated with the same topical IOP-lowering medication. The purpose of this study was to determine if this assumption is true.

DESIGN

Observational case series.

PARTICIPANTS AND CONTROLS

Forty-three patients with bilateral glaucoma or ocular hypertension who underwent bilateral treatment with a topical IOP-lowering medication.

METHODS

Patients were on 0 (81%) or 1 (19%) IOP-lowering medication at the time the medication was added in this study. Baseline IOP was the IOP at the treatment initiation visit, and IOP on treatment was assessed in both eyes on the first visit after addition of the medication. Linear regression of right-eye versus left-eye IOP reductions was performed.

MAIN OUTCOME MEASURE

Correlation of right-eye and left-eye IOP responses to therapy.

RESULTS

Right eyes demonstrated a 5.0-mmHg (26.9%) reduction, and left eyes demonstrated a 4.3-mmHg (23.7%) reduction. Linear regression of right-eye IOP reduction against left-eye IOP reduction gave a slope of 0.77 (Pearson correlation coefficient, r = 0.84; r2 = 0.70; P<0.0001).

CONCLUSIONS

Fellow-eye pairs exhibited marked symmetry in IOP responses to IOP-lowering medications.

Impact of diabetes on glaucoma screening using frequency-doubling perimetry

PURPOSE

To determine whether diabetes is a potential source of abnormal test results in glaucoma screening by use of frequency-doubling perimetry.

DESIGN

Observational case series.

PARTICIPANTS AND CONTROLS

Twenty-five patients with diabetes and 25 nondiabetic normal controls, all without cataract or glaucoma.

METHODS

Frequency-doubling perimetry using the C-20-5 screening mode was performed in 1 randomly selected eye of each participant. Abnormal test results were immediately repeated to reduce artifacts caused by test inexperience. Frequency-doubling technology (FDT) results were assigned a numerical score between 0 (normal) and 87 (no stimuli detected).

MAIN OUTCOME MEASURE

Abnormal FDT test scores.

RESULTS

Overall, 7 of 25 (28%) patients with diabetes and 1 of 25 (4%) normal controls had an abnormal test; the 1 normal subject with an abnormal test was subsequently determined to have an abnormal glucose tolerance test. Four of the 7 patients with diabetes with abnormal FDT tests had no evidence of diabetic retinopathy on clinical examination. Patients with diabetes had higher test scores than normal controls (8.9+/-16.9 vs. 1.0+/-4.4, P = 0.028) and had longer test times than normal controls (66.4+/-35.5 seconds vs. 48.3+/-11.2 seconds, P = 0.019).

CONCLUSIONS

Frequency-doubling perimetry is abnormal in some patients with diabetes, including some patients with diabetes without clinical evidence of diabetic retinopathy. Abnormal FDT testing in diabetic eyes may not represent glaucomatous visual field loss. Diabetes may be a source of "false-positive" test results when this technology is used for glaucoma screening.

The Proview phosphene tonometer fails to measure ocular pressure accurately in clinical practice*1

PURPOSE

To evaluate the Proview Eye Pressure Monitor as a medical instrument and as a technique for enabling a patient to obtain an accurate measure of his or her intraocular pressure (IOP).

DESIGN

An experimental laboratory evaluation and an independent prospective clinical study to test the reproducibility and accuracy of the Proview technique relative to Goldmann applanation tonometry.

PARTICIPANTS

For the laboratory study, we analyzed 3 tonometers, each packaged as a Proview Eye Pressure Monitor by Bausch & Lomb. In the independent prospective experimental study, 137 subjects participated, consisting of healthy volunteers and glaucoma patients.

METHODS

For laboratory testing, we held each tonometer with a micrometer to assure controlled positioning and pressed its sensing tip against a force meter that produced a calibrated, digital force reading. For clinical testing, we taught subjects (n = 137) to use the Proview technique in accordance with the manufacturer's instructions. Each subject obtained 5 measurements with each of the 5 different Proview devices. A clinician measured the IOP using Goldmann applanation tonometry.

MAIN OUTCOME MEASURES

We measured the absolute value, linearity, and repeatability of the force meter readings on the tonometers during the instrument laboratory evaluation. The accuracy was evaluated by comparing the Proview measurements to the Goldmann applanation measurements. Reproducibility of clinical Proview measurements was also measured. All measurements were in mmHg during the clinical evaluation.

RESULTS

Laboratory: There was a linear relationship between the pressures read by the Proview tonometers and known forces. The Proview tonometers read the maximum pressure applied. Clinical: The Proview technique is simple to use because it was comfortable and reproducible, with an average variance of the measurements by the same patient of 3.4 mmHg(2). Other variables besides IOP seem to affect the Proview pressure measurements, as seen in the large scatter in our data, measured by our correlation coefficient of r = 0.41. The sensitivity of the Proview technique to detect patients with high IOP (which we defined as a Goldmann pressure of >/=22 mmHg) is low; the Proview pressure identified only 18% (4/22) of these patients.

CONCLUSIONS

The Proview instrument and technique were reproducible. However, the Proview tonometer seems not to be reliable as an indicator of IOP. The sensitivity for detecting high IOP was low in this cohort, and the agreement with Goldmann applanation was poor for some individuals. This brings into question the underlying assumption that a force proportional to the IOP generates phosphenes.

Fixed combinations of topical glaucoma medications

PURPOSE OF REVIEW

Topical medical therapy remains the first line of treatment in the management of glaucoma. Utilization studies and clinical trials have demonstrated that many patients with glaucoma require multiple medications to achieve adequate control of intraocular pressure. Fixed combinations of commonly used drugs have been developed, tested, and in some (but not all) cases, approved for use in the United States and abroad. In this review the authors discuss the principles of fixed combination therapy and examine the existing fixed combinations.

RECENT FINDINGS

The first modern combination product was the dorzolamide-timolol fixed combination. It works better than either constituent and at least as well as concomitant therapy with both constituents. In comparison with newer agents, the dorzolamide-timolol fixed combination was equal in efficacy to latanoprost monotherapy, timolol and unoprostone concomitant therapy, and timolol and brimonidine concomitant therapy. Concomitant latanoprost and brimonidine demonstrated better efficacy than the dorzolamide-timolol fixed combination. The latanoprost-timolol fixed combination is available in many countries but not the United States. This combination has demonstrated modest additional efficacy over latanoprost monotherapy. The latanoprost-timolol fixed combination provided greater efficacy than concomitant timolol and brimonidine.

SUMMARY

Fixed combinations offer benefits of convenience, cost, and safety, but limit individualization of dosing. Understanding the advantages and disadvantages of prescribing fixed combinations facilitates success in using these products in clinical practice.

The uniocular drug trial and second-eye response to glaucoma medications

PURPOSE

To determine if the intraocular pressure (IOP) reduction observed in a uniocular trial correlates with the IOP reduction seen in the fellow eye when the same medication is then administered to the second eye of patients with glaucoma.

STUDY DESIGN

Observational case series.

PARTICIPANTS

Fifty-two patients with bilateral glaucoma.

METHODS

Glaucoma patients underwent uniocular trials of various glaucoma medications, then subsequently received the same drug in the fellow eye. The IOP reduction observed in the first eye was compared with that observed in the second eye to determine correlation.

MAIN OUTCOME MEASURE

Intraocular pressure reduction in fellow-eye pairs.

RESULTS

Intraocular pressure dropped a mean of 5.7+/-3.8 mmHg (mean +/- standard deviation) in the first eye after a uniocular trial, and 2.8+/-3.3 mmHg in the second eye after bilateral use. Regression analysis demonstrated a poor correlation between first-eye and second-eye response to the same medication (r(2) = 0.0174). To minimize possible contralateral IOP effects of first-eye therapy, a subset of 26 patients treated with latanoprost (which has little if any contralateral IOP effect, due to rapid systemic metabolism) was studied, with no improvement in correlation (r(2) = -0.0023).

CONCLUSION

Uniocular trials of glaucoma medications do not adequately predict second-eye IOP responses to the same medications. If both eyes of a glaucoma patient require IOP reduction, one should not assume that magnitudes of response will be equal in both eyes. The effect of a given medicine must be assessed independently for each eye.

Measuring central corneal thickness with ultrasound pachymetry

PURPOSE

To determine how many ultrasound pachymetry measurements are required to obtain a reasonable estimate of central corneal thickness.

METHODS

Five central corneal thickness measurements were obtained from each eye of 101 patients with normal corneas. The means of fewer than five readings were compared with the mean of five values for each eye to determine the incremental clinical value of additional measurements.

RESULTS

Compared with the mean of five values, fewer than three measurements per eye provided a mean central corneal thickness value with inadequate confidence. Conversely, means of more than three readings provided little additional confidence over means of three values.

CONCLUSIONS

Central corneal thickness by ultrasound pachymetry can be adequately assessed in the majority of eyes by taking three measurements per eye.

Frequency of asymmetric intraocular pressure fluctuations among patients with and without glaucoma

PURPOSE

To describe the frequency and magnitude of asymmetric fluctuations of intraocular pressure (IOP) between fellow eyes of glaucoma patients and normal subjects.

DESIGN

Observational case series.

PARTICIPANTS

Forty-two subjects without glaucoma and 38 glaucoma patients.

METHODS

By means of retrospective chart review, bilateral IOP measurements were examined over time for subjects without glaucoma and for glaucoma patients whose drug regimens remained unchanged during the period included in the study (at least five readings over at least 1 year). Asymmetric IOP fluctuations of at least 3 mmHg and representing at least a 15% change from baseline were identified.

MAIN OUTCOME MEASURE

Occurrence of spontaneous asymmetric IOP fluctuations.

RESULTS

Twenty-one of 42 subjects without glaucoma exhibited an asymmetric IOP fluctuation between two consecutive visits compared with 24 of 38 glaucoma patients (50% vs. 63.2%, respectively, P = 0.24). Compared with normal subjects, asymmetric IOP fluctuations were observed in 13 of 16 glaucoma patients with prior symmetrical bilateral ocular surgery (50% vs. 81.2%, respectively, P = 0.031), and 11 of 22 ocular surgery-naive glaucoma patients (50% vs. 50%, respectively, P = 1.0). No differences in the magnitudes of the asymmetric IOP fluctuations were noted between groups. Overall, asymmetric IOP fluctuations were observed in 13.7% of follow-up visits among normal subjects versus 16.3% of follow-up visits among glaucoma patients (P = 0.4).

CONCLUSIONS

Spontaneous asymmetric fluctuations of intraocular pressure between fellow eyes occur commonly in normal subjects and glaucoma patients. The frequency and magnitude of observed spontaneous asymmetric IOP fluctuations between consecutive clinical visits in glaucoma patients are sufficiently large to potentially confound the interpretation of monocular therapeutic drug trials.