Degree of angle closure and the intraocular pressure–lowering effect of latanoprost in subjects with chronic angle-closure glaucoma

Clinical implication of recent randomized control trial in primary angle-closure disease management

Blindness due to primary angle-closure glaucoma (PACG) can be reduced significantly if the ongoing angle-closure process is arrested at an early stage. Various treatments such as laser peripheral iridotomy (LPI), iridoplasty, and clear lens extraction (CLE) have been advocated as first-line therapy for primary angle-closure (PAC), PACG, and high-risk cases of primary angle-closure suspect (PACS). EAGLE study, propagated the effectiveness of CLE over LPI for the management of primary angle closure and have sparked controversy regarding the role of LPI as a first line procedure. Randomized controlled trials (RCT), systematic reviews, and meta-analyses of RCTs done on the same question provide us with a solid base for creating guidelines/modules for our day-to-day clinical practice. A systematic review was conducted, searching several databases, including PubMed, Cochrane Library, EMBASE, and ClinicalTrials.gov, for the last 16 years (January 2005–December 2021) for RCTs with data published related to primary angle-closure disease (PACD). The search strategy included the following terms: “Primary Angle Closure disease,” “Primary Angle Closure Glaucoma,” “Primary Angle Closure,” “Primary Angle Closure Suspect,” “clear lens extraction,” “laser iridotomy,” “laser peripheral iridotomy,” “argon laser peripheral iridoplasty,” “selective laser trabeculoplasty,” “trabeculectomy,” “randomized control trial,” and “meta-analysis of randomized control trial.” In this review, we will discuss recently published RCTs (within the last 16 years) for the management of PACD and their clinical implications in day-to-day practice.

Angle closure extent, anterior segment dimensions and intraocular pressure

AIM

To investigate the association between the extent of iridotrabecular contact and other quantitative anterior segment dimensions measured by swept-source optical coherence tomography (SS-OCT; CASIA SS-1000, Tomey, Nagoya, Japan) with intraocular pressure (IOP).

METHODS

Cross-sectional study. All subjects who were ≥50 years with no history of glaucoma, ocular surgery or trauma, underwent SS-OCT imaging (eight equally spaced radial scans), Goldman applanation tonometry and gonioscopy on the same day. We measured iridotrabecular contact (ITC) index and area, total volume of trabeculo-iris space area and angle opening distance at 500 and 750 from the scleral spur (TISA 500 and 750, AOD 500 and 750, respectively), anterior chamber depth (ACD), volume, area and width, pupil diameter, lens vault and iris volume.Their relationship with IOP (dependent variable) was assessed by locally weighted scatterplot smoothing (Lowess) regression with change-point analysis and generalised additive models adjusted for confounders.

RESULTS

2027 right eyes of mostly Chinese Singaporeans (90%) were analysed. ITC index above a threshold of ~60% (95% CI 34% to 92%) was significantly associated with higher IOP. Independent of the extent of ITC, ACD was also significantly associated with higher IOP below a threshold of 2.5 mm (95% CI 2.33 mm to 2.71 mm). Greater ITC index and shallower ACD had a joint association with IOP. A model including ACD and ITC index was more predictive of IOP than a model considering these variables separately, particularly for women with gonioscopically closed angles (R² 52.7%, p<0.05).

CONCLUSIONS

The extent of angle closure and the ACD below a certain threshold had a significant joint association with IOP. These parameters, as biometrical surrogates of mechanical obstruction of the aqueous outflow, may jointly contribute to elevated IOP, particularly in women with gonioscopic angle closure.

Meta-analysis of randomized controlled trials comparing latanoprost with other glaucoma medications in chronic angle-closure glaucoma

PURPOSE

To evaluate the efficacy and safety of latanoprost compared with other glaucoma medications in the treatment of chronic angle-closure glaucoma (CACG) and to provide the basis for clinical medication.

METHODS

Major literature databases were searched for randomized controlled trials (RCT) involving latanoprost among patients with CACG. Primary outcome measures were absolute changes in intraocular pressure (IOP) and incidence of ocular adverse events. Statistical analyses included the calculation of standardized mean difference (SMD) and relative risk (RR). The statistical analysis was performed using STATA version 12.0 software.

RESULTS

Ten RCT involving 1096 patients were included in this meta-analysis. Analysis showed that latanoprost was not significantly different from other glaucoma medications in reducing IOP (SMD = 0.29, 95% confidence interval [CI] -0.02 to 0.59, p=0.069). Further subgroup analysis revealed that latanoprost was superior compared with timolol (SMD = 0.64, 95% CI 0.46 to 0.82, p&lt;0.001) and marginally inferior to travoprost and bimatoprost (SMD = -0.19, 95% CI -0.35 to -0.02, p = 0.026). As for conjunctival hyperemia, latanoprost caused a higher proportion than timolol (RR = 2.36, 95% CI 1.27 to 4.37, p = 0.007). However, latanoprost was associated with lower incidence of conjunctival hyperemia (RR = 0.42, 95% CI 0.30 to 0.59, p&lt;0.001), and with fewer occurrence of other ocular side effects (excluding conjunctival hyperemia) than travoprost and bimatoprost (RR = 0.61, 95% CI 0.48 to 0.78, p&lt;0.001).

CONCLUSIONS

Travoprost and bimatoprost are superior in IOP control than latanoprost, but latanoprost is better tolerated in patients with CACG.

Imaging the effects of prostaglandin analogues on cultured trabecular meshwork cells by coherent anti-stokes Raman scattering

PURPOSE

The aim of this study was to nondestructively monitor morphological changes to the lipid membranes of primary cultures of living human trabecular meshwork cells (hTMC) without the application of exogenous label.

METHODS

Live hTMC were imaged using two nonlinear optical techniques: coherent anti-Stokes Raman scattering (CARS) and two-photon autofluorescence (TPAF). The hTMC were treated with a commercial formulation of latanoprost (0.5 μg/mL) for 24 hours before imaging. Untreated cells and cells treated with vehicle containing the preservative benzalkonium chloride (BAK; 2 μg/mL) were imaged as controls. After CARS/TPAF imaging, hTMC were fixed, stained with the fluorescent lipid dye Nile Red, and imaged by conventional confocal microscopy to verify lipid membrane structures.

RESULTS

Analysis of CARS/TPAF images of hTMC treated with latanoprost revealed multiple intracellular lipid membranes absent from untreated or BAK-treated hTMC. Treatment of hTMC with sodium fluoride or ouabain, agents shown to cause morphological changes to hTMC, also did not induce formation of intracellular lipid membranes.

CONCLUSIONS

CARS microscopy detected changes in living hTMC morphology that were validated by subsequent histological stain. Prostaglandin-induced changes to hTMC involved rearrangement of lipid membranes within these cells. These in vitro results identify a novel biological response to a class of antiglaucoma drugs, and further experiments are needed to establish how this effect is involved in the hypotensive action of prostaglandin analogues in vivo.

Efficacy of goniosynechialysis for advanced chronic angle-closure glaucoma

Purpose:

To evaluate the intraocular pressure (IOP)-lowering efficacy of goniosynechialysis (GSL) for advanced chronic angle-closure glaucoma (CACG) using a simplified slit-lamp technique.

Patients and methods:

Patients with CACG with one severely affected eye with best-corrected visual acuity below 20/200 and a mildly or functionally unaffected fellow eye were enrolled in this study. All patients underwent ophthalmologic examinations including measurement of visual acuity, best-corrected visual acuity, and IOP; biomicroscopy; specular microscopy; fundus examination; and gonioscopy followed by anterior chamber paracentesis and GSL for nasal peripheral anterior synechiae in the eye with severe CACG.

Results:

Thirty patients (18 men, 12 women) were identified as having CACG with an initial mean IOP of 47.1 ± 6.7 mmHg (range 39–61 mmHg) in the severely affected eye. One week after GSL, the mean IOP of the treated eyes decreased to 19.3 ± 2.8 mmHg (range 14–26 mmHg) without antiglaucoma medication (average decrease 27.7 ± 6.5 mmHg; range 16–41 mmHg), which was significant (P < 0.00001) compared with baseline. After an average follow-up period of 36.6 ± 1.0 months (range 35–38 months), the mean IOP stabilized at 17.4 ± 2.2 mmHg (range 12–21 mmHg). The nasal angle recess did not close again in any one of the patients during the follow-up period. The average significant (P < 0.00001) decrease in corneal endothelial cell density in the treated eyes was 260 ± 183 cells/mm² (range 191–328 cells/mm²).

Conclusions:

Anterior chamber paracentesis and GSL lowers IOP in advanced CACG, though it may lead to mild corneal endothelial cell loss.

Intraocular pressure-reducing effects of latanoprost versus timolol in chinese patients with chronic angle-closure glaucoma

PURPOSE

To compare the efficacy and safety of latanoprost and timolol in Chinese patients with chronic angle-closure glaucoma (CACG), who had undergone laser or surgical peripheral iridotomy but who continued to experience elevated intraocular pressure (IOP) levels.

PATIENTS AND METHODS

This 8-week, randomized, open-label, parallel, active-controlled study was conducted at 4 sites in China. Subjects were 18 to 75 years of age; had primary, unilateral, or bilateral CACG with an IOP between 21 and 35 mm Hg inclusive at screening; and had undergone peripheral iridotomy at least 1 month before study entry. Subjects were randomized (1:1) to receive 1 drop of latanoprost 0.005% (PM) or 1 drop of timolol 0.5% twice daily (AM and PM). Follow-up was at weeks 1, 2, 4, and 8. Primary efficacy endpoint: change in average IOP from baseline to week 8.

RESULTS

One hundred forty-two subjects were randomized into the latanoprost and timolol group; the analysis population included 141 subjects (latanoprost, n=71; timolol, n=70). Mean baseline average IOP levels were 24 mm Hg in both groups. The least square mean change from baseline to week 8 was -6.7 mm Hg for latanoprost versus -4.9 mm Hg for timolol [least square mean difference=1.8 mm Hg (95% confidence interval, 0.7-2.9); P<0.001]. Latanoprost was associated with significantly lower mean average IOP levels at each visit (P<0.05). Both treatments were well tolerated and no treatment-emergent adverse event was considered by investigators to be severe.

CONCLUSIONS

Once-daily administration of latanoprost 0.005% was significantly more effective in reducing IOP in Chinese patients with CACG than twice-daily instillation of timolol 0.5%. Both agents were well tolerated.

Angle-closure glaucoma-simpler answers to complex mechanisms: LXVI Edward Jackson Memorial Lecture

PURPOSE

To present evidence-based concepts that will explain mechanisms of angle-closure glaucoma.

DESIGN

Review of published evidence and personal perspective.

METHODS

Literature review and clinical research using imaging devices.

RESULTS

When the pupil dilates, the iris typically decreases its volume by losing extracellular fluid. Eyes with angle-closure lose less iris volume with pupil dilation, contributing to obstruction of the trabecular meshwork. Expansion of choroidal volume is a dynamic phenomenon and is a major risk factor in angle-closure. The mechanism of malignant glaucoma seems likely to result from poor conductivity of fluid through the vitreous, and past suggestions that it results from "misdirected" aqueous are not consistent with physiological principles.

CONCLUSIONS

Angle-closure and angle-closure glaucoma result from disturbed physiological mechanisms more than from simple anatomic measures, and future predictive testing can exploit knowledge of these factors.

Qualitative assessment of ultrasound biomicroscopic images using standard photographs: the liwan eye study

Objective. To classify anatomic features related to anterior chamber angles by a qualitative assessment system based on ultrasound biomicroscopy (UBM) images. Methods. Cases of primary angle-closure suspect (PACS), defined by pigmented trabecular meshwork that is not visible in two or more quadrants on static gonioscopy (cases) and systematically selected subjects (1 of every 10) who did not meet this criterion (controls) were enrolled during a population-based survey in Guangzhou, China. All subjects underwent UBM examination. A set of standard UBM images was used to qualitatively classify anatomic features related to the angle configuration, including iris thickness, iris convexity, iris angulation, ciliary body size, and ciliary process position. All analysis was conducted on right eye images. Results. Based on the qualitative grades, the difference in overall iris thickness between gonioscopically narrow eyes (n = 117) and control eyes (n = 57) was not statistically significant. The peripheral one third of the iris tended to be thicker in all quadrants of the PACS eyes, although the difference was statistically significant only in the superior quadrant (P = 0.008). No significant differences were found in the qualitative classifications of iris insertion, iris angulation, ciliary body size, and ciliary process position. The findings were similar when compared with the control group of eyes with wide angles in all quadrants. Conclusions. Basal iris thickness seems to be more relevant to narrow angle configuration than to overall iris thickness. Otherwise, the anterior rotation and size of the ciliary body, the iris insertion, and the overall iris thickness are comparable in narrow- and wide-angle eyes.

Mean target intraocular pressure and progression rates in chronic angle-closure glaucoma

PURPOSE

The aim of this study was to evaluate risk factors for progression in chronic angle-closure glaucoma (CACG) patients.

METHODS

A retrospective cohort of patient records in East Asia were evaluated for risk factors associated with progressive optic-disc and visual-field loss. There were 101 CACG patients with 5 years of follow-up.

RESULTS

Seventy-one percent (71%) of patients with intraocular pressures (IOP) of >22 mmHg progressed, whereas 26% of patients with IOPs of 13-21 mmHg progressed, and 0% of patients with IOPs of <12 mmHg progressed. The mean IOP was 16.6 +/- 3.4 mmHg in the stable group and 18.8 +/- 3.5 mmHg in the progressed group (P = 0.007). The highest average peak IOP was 23.2 +/- 6.3 mmHg in the stable group and 26.5 +/- 6.5 mmHg in the progressed group (P = 0.03). Generally, patients whose standard deviation of IOP was <2 mmHg (12% progressed) were more often stable, compared to those who were >3 mmHg (33% progressed). A multivariate regression analysis was positive for mean IOP as a clinically important risk factor for progression.

CONCLUSIONS

IOP reduction in CACG patients may help prevent progressive visual-field and optic-disc damage.

The long-term effect of Nd:YAG laser iridotomy on intraocular pressure in Taiwanese eyes with primary angle-closure glaucoma

BACKGROUND

To investigate the long-term effect of Nd:YAG laser iridotomy on intraocular pressure (IOP) in Taiwanese eyes with primary angle-closure glaucoma (PACG).

METHODS

The medical records of 81 patients (130 eyes) who were diagnosed with PACG and who had undergone Nd:YAG laser iridotomy between 1998 and 2002 were reviewed. According to the presence of symptomatic glaucoma attack, eyes were divided into an acute angle-closure glaucoma (AACG) group and chronic angle-closure glaucoma (CACG) group. In the AACG group, the acute episode was treated and resolved after Nd:YAG laser iridotomy. These eyes were diagnosed to have or developed glaucoma during the follow-up period. All patients were followed-up for at least 24 months. The presenting features, treatment and IOP during the follow-up period were analyzed.

RESULTS

The mean follow-up period was 44.1 +/- 17.8 months (median, 36 months). There were 27 eyes (from 25 patients) in the AACG group. Only 2 eyes (7.4%) did not require any treatment after Nd:YAG laser iridotomy. Eleven eyes (40.7%) eventually underwent filtering surgery at a mean of 3.2 months (median, 3 months) after Nd:YAG laser iridotomy. There were 103 eyes (from 56 patients) in the CACG group. Eighty-five eyes (82.5%) required further medical treatment, of which 21 eyes (20.4%) eventually received filtering surgery at a mean of 9.8 months (median, 5 months) after Nd:YAG laser iridotomy.

CONCLUSION

For most Taiwanese eyes with PACG after Nd:YAG laser iridotomy, additional medicine and surgery are required in the long term. Eyes in the AACG group needed more surgical intervention than those in the CACG group.

Correlation of previous acute angle-closure attack with extent of synechial angle closure in chronic primary angle-closure glaucoma patients

AIM

To document any correlation between previous acute angle-closure attack and the extent of synechial angle closure in chronic primary angle-closure glaucoma (PACG) patients.

METHODS

Consecutive cases of chronic PACG with patent peripheral iridotomy had gonioscopy performed. The extents of synechial angle closure of those chronic PACG eyes with previous documented acute angle-closure attack were compared to those eyes without such a history.

RESULTS

A total of 102 chronic PACG eyes of 102 patients were recruited. Twenty-seven eyes (26.5%) had a previous documented acute angle closure, while 75 eyes (73.5%) did not. The mean extent of synechial angle closure +/-1 SD was 307+/-68 degrees (range, 150-360 degrees) in those chronic PACG eyes with a history of previous acute angle closure, compared to 266+/-89 degrees (range, 90-360 degrees) in those chronic PACG eyes without such a history (P=0.03, Student's t-test). There were no statistically significant differences between the two groups in age, LogMAR visual acuity, intraocular pressure (IOP), number of glaucoma eye drops, vertical cup-to-disk ratio, mean deviation or pattern SD in Humphrey automated perimetry, and anterior chamber depth (P>0.05).

CONCLUSION

Previous acute angle-closure attack correlated with more extensive synechial angle closure in chronic PACG patients in this study.

Comparative Evaluation of Bimatoprost Monotherapy in Primary Chronic Angle Closure and Primary Open Angle Glaucoma Eyes: A Three-Year Study

AIMS

The aim of this study was to compare the long-term efficacy of bimatoprost 0.03% monotherapy in primary open angle glaucoma (POAG) versus primary chronic angle closure glaucoma (PCACG) eyes.

METHODS

A total of 55 consecutive primary adult glaucoma patients on bimatoprost monotherapy were prospectively evaluated in this 3-year, open-labeled, uncontrolled study. The primary outcome was the evaluation of a difference in the response to therapy of POAG eyes, as compared to PCACG eyes over a follow-up of 3 years.

RESULTS

In the POAG group, the mean intraocular pressure (IOP) at the 36-month followup was found to be increased by 2.10 (+/-3.90) mmHg (confidence interval [CI], 0.975-4.185), compared to the mean IOP at 1 month (P = 0.047). In the PCACG group, the mean IOP at the 36-month follow-up was increased by 3.66) (+/- 3.34) mmHg (CI, 6.241-1.092), compared to the mean IOP at 1 month (P = 0.011). This upward drift in IOP was higher in the PCACG group, compared to the POAG group, but this was not statistically significant (P = 0.54). Patients with POAG and PCACG showed a 50% and 40% chance of having an IOP of <18 mmHg with bimatoprost monotherapy (P = 0.23), respectively, at the 3-year follow-up.

CONCLUSIONS

This study showed that bimatoprost 0.03% monotherapy significantly lowers IOP in both POAG and PCACG eyes over a period of 3 years, though its efficacy appeared to decrease over time, to a similar extent, in both groups.

Comparison of the Effects of Latanoprost and Travoprost on Intraocular Pressure in Chronic Angle-Closure Glaucoma

PURPOSE

The aim of this study was to compare the intraocular pressure (IOP)-lowering effect of latanoprost and travoprost as primary therapy in patients with chronic angle-closure glaucoma (CACG) after peripheral iridotomy.

METHODS

Seventy-three (73) CACG patients with IOP>19 mmHg after peripheral iridotomy and without previous antiglaucoma medication were consecutively recruited. CACG was defined as the presence of chronically elevated IOP, glaucomatous optic neuropathy, and a corresponding visual field defect in eyes with occludable angle and peripheral anterior synechiae on gonioscopy. Patients were randomly assigned to 2 groups, based on daily treatment with either latanoprost 0.005% or travoprost 0.004% in the evening for 12 weeks. The IOP was measured at 9 AM and 4 PM at baseline and at 4, 8, and 12 weeks. Between-group differences in mean diurnal IOP and IOP reduction were analyzed.

RESULTS

After 12 weeks of treatment, mean IOP for both the latanoprost and travoprost groups was significantly reduced, when compared to the baseline IOP (from 21.3+/-1.8 mmHg to 16.0+/-2.3 mmHg and 21.7+/-1.7 to 16.7+/-2.2 mmHg; P<0.001 for both). There was no significant difference in IOP reduction between the 2 treatment groups (P=0.19). At 4 and 8 weeks, the IOP changes from the baseline were statistically significant at all time points for both drugs (all P<0.001).

CONCLUSIONS

Both latanoprost and travoprost significantly reduced IOP in our sample of CACG patients after peripheral iridotomy.

Comparison of Latanoprost Monotherapy and Combined Therapy of 0.5% Timolol and 1% Dorzolamide in Chronic Primary Angle-Closure Glaucoma (CACG) in Japanese Patients

To compare the efficacy, adverse effects, and patient compliance of latanoprost monotherapy with unfixed combination therapy with 0.5% timolol maleate and 1% dorzolamide in the treatment of chronic primary angle-closure glaucoma (CACG), 36 Japanese patients with CACG following laser iridotomy (LPI) were treated for 12 weeks with instillation of latanoprost alone or with unfixed combination therapy of 0.5% timolol maleate and 1% dorzolamide hydrochloride. After 12 weeks of treatment, latanoprost reduced intraocular pressure (IOP) from 22.2 +/- 2.0 mmHg to 14.8 +/- 1.9 mmHg (33% reduction); timolol maleate and dorzolamide hydrochloride also reduced IOP from 22.5 +/- 2.2 mmHg to 17.1 +/- 2.7 mmHg (24% reduction). Latanoprost monotherapy significantly lowered IOP compared with unfixed combination therapy of 0.5% timolol maleate and 1% dorzolamide hydrochloride. Furthermore, a systemic adverse effect of bradycardia was not observed in the latanoprost monotherapy group. Concerning compliance, no significant difference was observed between the two groups. Thus, latanoprost monotherapy is more effective than unfixed combination therapy with 0.5% timolol maleate and 1% dorzolamide in the treatment of CACG following relief of pupillary block in Japanese patients.