Long-term Outcomes in Fellow Eyes after Acute Primary Angle Closure in the Contralateral Eye

Lens extraction versus laser peripheral iridotomy for acute primary angle closure

BACKGROUND

Acute primary angle closure (APAC) is a potentially blinding condition. It is one of the few ophthalmic emergencies and carries high rates of visual morbidity in the absence of timely intervention. Laser peripheral iridotomy (LPI) has been the standard of care thus far. However, LPI does not eliminate the long-term risk of chronic angle closure glaucoma and other associated sequelae. There has been increasing interest in lens extraction as the primary treatment for the spectrum of primary angle closure disease, and it is as yet unclear whether these results can be extrapolated to APAC, and whether lens extraction provides better long-term outcomes. We therefore sought to evaluate the effectiveness of lens extraction in APAC to help inform the decision-making process.  OBJECTIVES: To assess the effect of lens extraction compared to LPI in the treatment of APAC.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (which contains the Cochrane Eyes and Vision Trials Register) (2022, Issue 1), Ovid MEDLINE, Ovid MEDLINE E-pub Ahead of Print, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily (January 1946 to 10 January 2022), Embase (January 1947 to 10 January 2022), PubMed (1946 to 10 January 2022), Latin American and Caribbean Health Sciences Literature Database (LILACS) (1982 to 10 January 2022), ClinicalTrials.gov, and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP). We did not use any date or language restrictions in the electronic search. We last searched the electronic databases on 10 January 2022.

SELECTION CRITERIA

We included randomized controlled clinical trials comparing lens extraction against LPI in adult participants ( ≥ 35 years) with APAC in one or both eyes.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methodology and assessed the certainty of the body of evidence for prespecified outcomes using the GRADE approach.

MAIN RESULTS

We included two studies conducted in Hong Kong and Singapore, comprising 99 eyes (99 participants) of predominantly Chinese origin. The two studies compared LPI with phacoemulsification performed by experienced surgeons. We assessed that both studies were at high risk of bias. There were no studies evaluating other types of lens extraction procedures.  Phacoemulsification may result in an increased proportion of participants with intraocular pressure (IOP) control compared with LPI at 18 to 24 months (risk ratio (RR) 1.66, 95% confidence interval (CI) 1.28 to 2.15; 2 studies, n = 97; low certainty evidence) and may reduce the need for further IOP-lowering surgery within 24 months (RR 0.07, 96% CI 0.01 to 0.51; 2 studies, n = 99; very low certainty evidence). Phacoemulsification may result in a lower mean IOP at 12 months compared to LPI (mean difference (MD) -3.20, 95% CI -4.79 to -1.61; 1 study, n = 62; low certainty evidence) and a slightly lower mean number of IOP-lowering medications at 18 months (MD -0.87, 95% CI -1.28 to -0.46; 1 study, n = 60; low certainty evidence), but this may not be clinically significant. Phacoemulsification may have little to no effect on the proportion of participants with one or more recurrent APAC episodes in the same eye (RR 0.32, 95% CI 0.01 to 7.30; 1 study, n = 37; very low certainty evidence). Phacoemulsification may result in a wider iridocorneal angle assessed by Shaffer grading at six months (MD 1.15, 95% CI 0.83 to 1.47; 1 study, n = 62; very low certainty evidence). Phacoemulsification may have little to no effect on logMAR best-corrected visual acuity (BCVA) at six months (MD -0.09, 95% CI -0.20 to 0.02; 2 studies, n = 94; very low certainty evidence). There was no evidence of a difference in the extent of peripheral anterior synechiae (PAS) (clock hours) between intervention arms at 6 months (MD -1.86, 95% CI -7.03 to 3.32; 2 studies, n = 94; very low certainty evidence), although the phacoemulsification group may have less PAS (degrees) at 12 months (MD -94.20, 95% CI -140.37 to -48.03; 1 study, n = 62) and 18 months (MD -127.30, 95% CI -168.91 to -85.69; 1 study, n = 60).  In one study, there were 26 adverse events in the phacoemulsification group: intraoperative corneal edema (n = 12), posterior capsular rupture (n = 1), intraoperative bleeding from iris root (n = 1), postoperative fibrinous anterior chamber reaction (n = 7), and visually significant posterior capsular opacification (n = 5), and no cases of suprachoroidal hemorrhage or endophthalmitis. There were four adverse events in the LPI group: closed iridotomy (n = 1) and small iridotomies that required supplementary laser (n = 3). In the other study, there was one adverse event in the phacoemulsification group (IOP > 30 mmHg on day 1 postoperatively (n = 1)), and no intraoperative complications. There were five adverse events in the LPI group: transient hemorrhage (n = 1), corneal burn (n = 1), and repeated LPI because of non-patency (n = 3).  Neither study reported health- or vision-related quality of life measures.

AUTHORS' CONCLUSIONS

Low certainty evidence suggests that early lens extraction may produce more favorable outcomes compared to initial LPI in terms of IOP control. Evidence for other outcomes is less clear. Future high-quality and longer-term studies evaluating the effects of either intervention on the development of glaucomatous damage and visual field changes as well as health-related quality of life measures would be helpful.

Immune Responses in the Glaucomatous Retina: Regulation and Dynamics

Glaucoma is a multifactorial disease resulting in progressive vision loss due to retinal ganglion cell (RGC) dysfunction and death. Early events in the pathobiology of the disease include oxidative, metabolic, or mechanical stress that acts upon RGC, causing these to rapidly release danger signals, including extracellular ATP, resulting in micro- and macroglial activation and neuroinflammation. Danger signaling also leads to the formation of inflammasomes in the retina that enable maturation of proinflammatory cytokines such IL-1β and IL-18. Chronic neuroinflammation can have directly damaging effects on RGC, but it also creates a proinflammatory environment and compromises the immune privilege of the retina. In particular, continuous synthesis of proinflammatory mediators such as TNFα, IL-1β, and anaphylatoxins weakens the blood–retina barrier and recruits or activates T-cells. Recent data have demonstrated that adaptive immune responses strongly exacerbate RGC loss in animal models of the disease as T-cells appear to target heat shock proteins displayed on the surface of stressed RGC to cause their apoptotic death. It is possible that dysregulation of these immune responses contributes to the continued loss of RGC in some patients.

Assessment of Reasons for Presentation in New Primary Glaucoma Patients and Identification of Risk Factors for Late Presentation

PURPOSE

To evaluate the reasons for seeking care among South Indian primary glaucoma patients and to determine the relationship of various patient characteristics to glaucoma severity at presentation.

DESIGN

Cross-sectional study.

PARTICIPANTS

One hundred sixty-one new primary open-angle glaucoma (POAG) and primary angle-closure glaucoma (PACG) patients seeking treatment at a tertiary eye hospital.

METHODS

After confirmation of diagnosis, participants' clinical information and their reported reasons for presentation were assessed. Data collected include age, gender, education, occupation, rural or urban residence, distance traveled to the hospital, method of transportation, need for an accompanying person, place of screening before referral or whether they came by themselves for testing. Advanced glaucoma was defined by a cup-to-disc ratio of 0.85 or higher in either eye.

MAIN OUTCOME MEASURES

The primary outcomes were the various reasons for presentation. The secondary outcome was to determine whether a relationship existed between the patient characteristics mentioned above and presentation with advanced glaucoma.

RESULTS

The mean age of the participants was 60.8 years. The primary reason for presentation was defective vision (55.2%) followed by routine ophthalmic evaluation (13%). Sixty-four patients (39.8%) showed advanced glaucoma in at least 1 eye at presentation. Unilateral blindness was noted in 18 patients (11.2%). The mean vertical cup-to-disc ratio was 0.66 (standard deviation [SD], ±0.16) in the better-seeing eye and 0.76 (SD, ±0.12) in the worse-seeing eye. The mean presenting intraocular pressure was 22.9 mmHg in POAG and 25.5 mmHg in PACG patients. Multivariate logistic regression analyses showed that people who are currently unemployed (P < 0.001; odds ratio [OR], 4.19; 95% confidence interval [CI], 1.95-8.99) and rural residence (P = 0.04; OR, 0.46; 95% CI, 0.21-0.99) had greater odds of demonstrating advanced glaucoma at presentation. Presentation with defective vision, older age, and education less than college graduation were associated with greater odds of showing advanced glaucoma in univariate analysis, but not in multivariate analyses.

CONCLUSIONS

In a South Indian population, absence of work and rural residence was associated with advanced glaucoma at presentation. The population in whom these risk factors are common should be targeted for screening and outreach.

A Minimally Invasive Experimental Model of Acute Ocular Hypertension with Acute Angle Closure Characteristics

Purpose

To describe a minimally invasive experimental model of acute ocular hypertension (OHT) with characteristics of acute angle closure (AAC).

Methods

Adult C57/Bl6 mice (n = 31) were subjected to OHT in one eye using a modified circumlimbal suture technique that elevated intraocular pressure (IOP) for 30 minutes. Contralateral un-operated eyes served as controls. IOP, anterior segment optical coherence tomography, and fundus fluorescein angiography (FFA) were performed. The positive scotopic threshold response (pSTR) and a-wave and b-wave amplitudes were also evaluated. Retinal tissues were immunostained for the retinal ganglion cell (RGC) marker RBPMS and the glial marker GFAP.

Results

OHT eyes developed shallower anterior chambers and dilated pupils. FFA showed focal leakage in 32.2% of OHT eyes, but in none of the control eyes. pSTR was significantly reduced at week 1 in OHT eyes compared to control eyes (57.3 ± 7.2 µV vs. 106.9 ± 24.8 µV; P < 0.05), but a- and b-waves were unaffected. GFAP was upregulated in OHT eyes but not in control eyes or eyes that had been sutured without OHT. RGC density was reduced in OHT eyes after 4 weeks (3857 ± 143.8) vs. control eyes (4469 ± 176.0) (P < 0.05).

Conclusions

Our minimally invasive model resulted in acute OHT with characteristics of AAC in the absence of non-OHT-related neuroinflammatory changes arising from ocular injury alone.

Translational Relevance

This model provides a valuable approach to studying specific characteristics of a severe blinding disease in an experimental setting. Focal areas of ischemia were demonstrated, consistent with clinical studies of acute angle closure patients elsewhere, which may indicate the need for further research into how this could affect visual outcome in these patients.

Factors associated with blindness three months following treatment for acute primary angle glaucoma

AIMS

To study the risk factors associated with blindness after treatment of acute primary angle closure (APAC), and to identify the critical time window to decrease rate of blindness.

METHODS

In this multicentre retrospective case series, 1030 consecutive subjects (1164 eyes) with APAC in China were recruited. The rates of blindness were analysed up to 3 months after treatment of APAC. A logistic regression was used to identify the risk factors associated with blindness, including age, gender, distance to hospital, rural or urban settings, treatment method, education level, time from symptom to treatment (TST, hours) and presenting intraocular pressure (IOP). The critical time window associated with a blindness rate of ≤1% was calculated based on a cubic function by fitting TST to the rate of blindness at each time point.

RESULTS

The rate of blindness after APAC was 12.54% after treatment. In multivariate regression, education level, TST and presenting IOP were risk factors for blindness (p=0.022, 0.004 and 0.001, respectively). The critical time window associated with a blindness rate of ≤1% was 4.6 hours.

CONCLUSIONS AND RELEVANCE

Education level, TST and presenting IOP were risk factors for blindness after APAC. Timely medical treatment is key in reducing blindness after APAC.

Safety and Efficacy of 0.1% Nepafenac versus 1% Prednisolone Acetate Eye Drops after Laser Peripheral Iridotomy: A Prospective, Randomized Trial

PURPOSE

To compare 0.1% nepafenac, a topical nonsteroidal anti-inflammatory drop, with 1% prednisolone acetate in controlling inflammation after neodymium:yttrium-aluminum-garnet laser peripheral iridotomy (LPI) in primary angle-closure suspects (PACS).

DESIGN

Randomized controlled trial.

PARTICIPANTS

One hundred fifty-two PACS undergoing bilateral LPI.

METHODS

Patients were randomized to 0.1% nepafenac or 1% prednisolone acetate eye drops in both eyes. Medications were given 4 times daily for 7 days, then twice daily for additional 7 days. Investigators were masked to the type of medication. Right eyes in patients with bilateral PACS and the PACS eye in asymmetrical disease (primary angle closure in fellow eye) were analyzed.

MAIN OUTCOME MEASURES

Noninferior control of inflammation, defined as absence of cell in the anterior chamber at 2 weeks and absence of rebound iritis with medication discontinuation, was the primary outcome, whereas difference in the rise in intraocular pressure (IOP) was a secondary outcome.

RESULTS

Both groups were comparable in baseline characteristics, including IOP and total laser energy. Nepafenac was noninferior to prednisolone with regard to inflammation control, with 1 nepafenac-treated eye (1.3%) not meeting the primary end point because of 1+ anterior chamber cell at 2 weeks and 4 prednisolone-treated eyes (5.4%) failing to meet the primary end point because of rebound iritis (P < 0.001). A greater increase in IOP from baseline to 2 weeks was observed in the prednisolone group compared with the nepafenac group (+2.6 mmHg vs. +0.6 mmHg; P = 0.004), although at 4 weeks, IOP was not significantly different than baseline in either group (P > 0.05 for both). Two weeks after LPI, 3 nepafenac-treated eyes and 10 prednisolone-treated eyes demonstrated a 6- to 15-mmHg IOP elevation from baseline (P = 0.10), whereas 2 prednisolone-treated eyes and no nepafenac-treated eyes showed IOP elevation of more than 15 mmHg (P = 0.20). Four weeks after LPI, more prednisolone-treated eyes showed IOP elevation of 6 to 15 mmHg as compared with nepafenac-treated eyes (6 eyes vs. 1 eye; P = 0.04); no eyes showed IOP elevation of more than 15 mmHg.

CONCLUSIONS

Nepafenac was noninferior to prednisolone in controlling inflammation after LPI in PACS.

Pentacam changes in primary angle-closure glaucoma after different lines of treatment

AIM

To assess the changes in the anterior chamber parameters using Pentacam following four different lines of treatment of primary angle-closure glaucoma (PACG).

METHODS

A retrospective comparative study included 126 patients (126 eye) presented within 24-48h after acute angle-closure glaucoma (AACG). Patients were divided into 2 groups: group A (68 eyes) with controlled intraocular pressure (IOP) ≤21 mm Hg, which included subgroup A1 (34 eyes) with clear lens underwent Nd:YAG laser peripheral iridotomy (LPI) and subgroup A2 (34 eyes) with cataract underwent standard phacoemulsification; and group B (58 eyes) with uncontrolled IOP, which included subgroup B1 (30 eyes) with clear lens underwent trabeculectomy and subgroup B2 (28 eyes) with cataract underwent combined phacoemulsification and trabeculectomy. Patients were followed up for at least 3mo. Primary outcomes were Pentacam anterior segment measurements [anterior chamber angle (ACA) and depth (ACD)]. Secondary outcomes were changes in IOP, visual acuity (VA) and recorded complications.

RESULTS

At the 3rd month, there was significant increase in the ACA values in all studied groups compared to preoperative values (P<0.001). The highest percent of increase in ACA was recorded in phacotrabeculectomy group B2 (128.40%). There was significant increase in ACD values at 3rd month compared with baseline values (P<0.001) for groups A1, A2, and B2; without change in B1 trabeculectomy group. The maximum deepening of ACD was noticed in group B2 with 94.27% increase. Significant decrease in postoperative IOP in groups A2, B1 and B2 (P<0.001, P=0.014, and P<0.001 respectively). In group A1 there was significant increase in 3rd month postoperative IOP from baseline values (P<0.001). The maximum decrease in IOP was noticed in group B2 with 59.54% decrease. VA improvement in 3rd month postoperative was recorded in all studied groups, maximum VA improvement was observed in group B2 up to 0.2 logMAR.

CONCLUSION

Pentacam can be a helpful tool in studying and comparing the effect of the different lines of management of PACG on the anterior chamber measures. Phacotrabeculectomy was proved to be an effective line for managing PACG with resultant significant increase in the anterior chamber parameters, IOP reduction as well as maximum VA improvement. LPI has only temporary effect on IOP with significant changes in ACA and ACD. Phacoemuslification alone can be an option in treating PACG. Trabeculectomy resulted in temporary increase in the anterior chamber parameter which subsequently returned to baseline values.

Aqueous proinflammatory cytokines in acute primary angle-closure eyes

AIM

To evaluate changes of proinflammatory cytokines in aqueous humor of patients with acute primary angle-closure (APAC) and age-related cataracts.

METHODS

Twenty eyes of 20 APAC patients and 15 eyes of 15 age-related cataract patients were included in this cross-sectional study. Aqueous humor samples were collected prospectively. The levels of 20 proinflammatory cytokines were evaluated in the aqueous humor of the APAC and cataract patients using the multiplex bead immunoassay technique. Clinical data were collected for correlation analysis.

RESULTS

Seven of the 20 proinflammatory cytokines included in the magnetic bead panel were detectable in both APAC eyes and cataract eyes: interleukin (IL)-10, IL-12, IL-15, IL-21, IL-6, chemokine (C-C motif) ligand 20, and tumor necrosis factor alpha (TNF-α). IL-27 was only detectable in APAC eyes. Compared with the cataract eyes, the APAC eyes had significantly elevated concentrations of IL-12 (P=0.036), IL-15 (P=0.001), IL-6 (P=0.012), and IL-27 (only detectable in APAC eyes). Age was positively correlated with IL-12 (P=0.022) and IL-6 (P=0.037), and time elapsed between APAC onset and aqueous humor samples collection was positively correlated with IL-15 (P=0.037), IL-27 (P=0.040), and TNF-α (P=0.042).

CONCLUSION

Several proinflammatory cytokines including IL-12, IL-15, IL-6 and IL-27, were elevated in the APAC eyes and may be implicated in its pathologic mechanism.

Patient-Reported Vision-Related Quality-of-Life Differences between Primary Angle-Closure Glaucoma and Primary Open-Angle Glaucoma

Purpose

To investigate the different impacts on patient-reported vision-related quality of life (pVRQOL) outcomes in patients with primary angle-closure glaucoma(PACG) and primary open-angle glaucoma(POAG).

Methods

Prospective cross-sectional study. PACG and POAG patients who had a best-corrected visual acuity(BCVA) in the better eye equal to or better than 20/60, intraocular pressure controlled at or below 25 mmHg and reliable visual field test were invited to participate. The control group included patients with BCVA in the better eye equal to or better than 20/60 and who did not have major eye disease. A validated Taiwanese version of the 25-item National Eye Institute Visual Function Questionnaire (NEI VFQ-25(T)) was performed to assess pVRQOL. The association between each domain of NEI VFQ-25(T) among 3 groups was determined using multivariable linear regression analysis.

Results

A total of 106 PACG, 186 POAG, and 95 controls were enrolled. In multivariable regression analysis of all three groups(PACG/POAG/controls), compared to POAG, PACG showed a weakly positive association with social functioning (R² = 0.13, β = 0.22, P = 0.04). PACG showed no significantly negative impact on pVRQOL compared to controls. Taking only glaucoma patients into consideration, PACG patients had a higher score on social functioning compared to POAG (R² = 0.16, β = 0.27, P = 0.01). The results of other domains of NEI VFQ-25(T) between the two groups did not differ significantly(p>0.05).

Conclusions

In patients with controlled disease, the impact of PACG and POAG on most domains of NEI VFQ-25(T) were similar, except for better social functioning in PACG compared to POAG.

Qualitative evaluation of anterior segment in angle closure disease using anterior segment optical coherence tomography

PURPOSE

To evaluate different mechanisms of primary angle closure (PAC) and to quantify anterior chamber (AC) parameters in different subtypes of angle closure disease using anterior segment optical coherence tomography (AS-OCT).

METHODS

In this prospective study, 115 eyes of 115 patients with angle closure disease were included and categorized into three groups: 1) fellow eyes of acute angle closure (AAC; 40 eyes); 2) primary angle closure glaucoma (PACG; 39 eyes); and 3) primary angle closure suspect (PACS; 36 eyes). Complete ophthalmic examination including gonioscopy, A-scan biometry, and AS-OCT were performed. Based on the AS-OCT images, 4 mechanisms of PAC including pupillary block, plateau iris configuration, thick peripheral iris roll (PIR), and exaggerated lens vault were evaluated. Angle, AC, and lens parameter variables were also evaluated among the three subtypes.

RESULTS

There was a statistically significant difference in the mechanism of angle closure among the three groups (p = 0.03). While the majority of fellow eyes of AAC and of PACS eyes had pupillary block mechanism (77.5% and 75%, respectively), only 48.7% of PACG eyes had dominant pupillary block mechanism (p = 0.03). The percentage of exaggerated lens vault and plateau iris mechanisms was higher in PACG eyes (25.5% and 15.4%, respectively). Fellow eyes of AAC had the shallowest AC (p = 0.01), greater iris curvature (p = 0.01), and lens vault (p = 0.02) than PACS and PACG eyes. Iris thickness was not significantly different among the three groups (p = 0.45).

CONCLUSION

Using AS-OCT, we found that there was a statistically significant difference in the underlying PAC mechanisms and quantitative AC parameters among the three subtypes of angle closure disease.

Long-term outcomes after acute primary angle closure in a White Caucasian population

Introduction

Very limited data is available on the morbidity and progression to primary angle closure glaucoma (PACG) in White Caucasian individuals following acute primary angle closure (APAC).

Our aim is to identify the number of eyes who developed PACG following an APAC attack and to determine the risk factors for PACG development in a White Caucasian population in the United Kingdom (UK). We assessed the rate of blindness and visual impairment in the affected eye as defined by the World Health Organisation.

Methods

Retrospective observational study including 48 consecutive eyes of 46 White Caucasian subjects who presented with APAC to a tertiary referral unit in the United Kingdom.

Eyes affected by glaucomatous optic neuropathy at presentation were excluded. We included in our analysis socio-demographic variables, ophthalmic findings, investigations and treatment.

Results

The mean final follow up period was 27 months ± 14 standard deviation (SD). Seven (15 %) eyes developed PACG. Statistical analysis showed that the following factors were linked to a higher risk of progression: length of symptoms before presentation and time taken to break the attack. The intraocular pressure (IOP) was significantly higher in the group who developed PACG at the one- and six-month visit compared to the group which did not develop the disease.

At the final visit 3 (6 %) eyes were blind while 5 (10 %) were visually impaired. PACG was responsible for visual impairment in 2 (4 %) eyes but not for any case of blindness.

Conclusions

Delayed presentation, length of time taken to break the attack and poor IOP control can result in PACG development and visual impairment. APAC causes a low long-term visual morbidity in White Caucasians.

Postiridotomy ultrasound biomicroscopy features in the fellow eye of Chinese patients with acute primary angle-closure and chronic primary angle-closure glaucoma

PURPOSE

To compare the features of postiridotomy ultrasound biomicroscopy (UBM) in Chinese patients with acute primary angle-closure (aPAC) and with chronic primary angle-closure (cPAC) glaucoma.

PATIENTS AND METHODS

Consecutive cases were classified into acute and chronic groups. The acute group included 77 patients with unilateral aPAC. The chronic group included 57 patients with unilateral advanced cPAC glaucoma. In both the groups, the patients' fellow eye underwent a laser iridotomy and was studied. The main outcome measures included qualitative UBM parameters such as a plateau iris, anterior iris insertion, and an anteriorly rotated ciliary process and quantitative UBM parameters such as central anterior chamber depth (ACD), basal iris thickness (IT500), and scleral ciliary process angle (SCPA).

RESULTS

For the qualitative parameters, more eyes in the chronic group had a plateau iris (P=0.046), an anterior iris insertion (P=0.222), and an anteriorly rotated ciliary process (P=0.090) than those in the acute group. For the quantitative parameters, the eyes in the chronic group had a deeper ACD (P<0.001), thicker IT500 (P<0.001), and smaller SCPA (P<0.001) than those in the acute group.

CONCLUSIONS

The UBM features of Chinese patients with cPAC include a more plateaued iris, a thicker basal iris, and a smaller SCPA, whereas patients with aPAC may have a shallower ACD. For Chinese patients, a nonpupillary block component may play a more important role in asymptomatic cPAC than in aPAC.

Family history is a strong risk factor for prevalent angle closure in a South Indian population

PURPOSE

To compare the prevalence of angle closure among siblings of patients with open angles (OAs), suspect angle closure (PACS), and either primary angle closure (PAC) or PAC glaucoma (PACG).

DESIGN

Cross-sectional, clinical study.

PARTICIPANTS

A total of 303 South Indian sibling pairs, including 81 OA probands, 143 PACS probands, and 79 PAC/PACG probands.

METHODS

Probands and siblings underwent a clinical examination, including gonioscopy by a masked grader, applanation tonometry, slit-lamp biomicroscopy, optic nerve evaluation, and A-scan ultrasonography. Probands and siblings were classified into 1 of 3 groups based on the phenotype of the more severely affected eye: OA, PACS, or PAC/PACG. Multivariable regression models were used to estimate the odds of prevalent angle closure in PACS or PAC/PACG siblings compared with OA siblings.

MAIN OUTCOME MEASURES

Prevalence and relative prevalence of angle closure and PAC/PACG among OA, PACS, and PAC/PACG siblings.

RESULTS

Mean sibling age was 49.7 ± 8.7 years, and 56.6% of siblings were females. Angle closure was more prevalent in both PACS siblings (35.0%) and PAC/PACG siblings (36.7%) compared with OA siblings (3.7%; P < 0.001). There was PAC/PACG present in 11.4% of PAC/PACG siblings compared with 4.9% of PACS siblings (P = 0.07) and 0% of OA siblings (P = 0.002). In multivariable models adjusting for sibling age and sex, the odds of angle closure was 13.6 times greater in angle closure (PACS or PAC/PACG) siblings compared with OA siblings (95% confidence interval [CI], 4.1-45.0; P < 0.001). Sibling angle-closure risk was also greater in female (odds ratio [OR], 2.3; 95% CI, 1.3-4.0; P = 0.005) and older siblings (OR, 1.5 per 10-year increment; 95% CI, 1.1-2.0; P = 0.02). Siblings of PAC/PACG probands had a 2.3-fold greater odds (95% CI, 0.8-6.5) of having PAC/PACG compared with siblings of PACS probands, although the association was not significant (P = 0.13).

CONCLUSIONS

In the South Indian population screened, siblings of angle-closure patients had a >1 in 3 risk of prevalent angle closure, whereas siblings of PAC/PACG patients had a >10% risk of prevalent PAC/PACG. Screening siblings of angle-closure patients is likely to be of high yield in finding undetected angle closure.

Quantification of retinal nerve fiber layer thickness after unilateral acute primary angle closure in Asian Indian eyes

PURPOSE

To determine retinal nerve fiber layer thickness (RNFLT) using Spectral optical coherence tomography/scanning laser ophthalmoscope (Spectral OCT/SLO) in Asian Indian eyes after single, unilateral attack of acute primary angle closure (APAC).

METHODS

Thirty-two patients with unilateral attack of APAC with normal optic disc and normal visual field, unaffected fellow eyes, and 35 age-matched normal control eyes were enrolled for the study. Six weeks after the remission of acute attack, peripapillary average, quadrant, and clock-hour RNFLT were compared between 3 groups using Spectral OCT/SLO.

RESULTS

APAC patients had mean IOP of 51.3±13.3 mm Hg (range, 40-74) at the time of presentation with acute attack in the affected eye and 14.9±2.9 mm Hg at 6 weeks after resolution of APAC. Duration of symptoms of acute attack was 35.9±23.8 hours. Significant differences were found between RNFLT in APAC and fellow eyes for most the parameters except for 1, 4, 6, and 7-o'clock-hour sector. Most of the RNFLT parameters showed statistically significant difference between APAC and normal control eyes except for temporal quadrant, 6, 7-o'clock-hour sectors. Statistically significant differences were found between RNFLT in unaffected fellow and normal control eyes for most of the parameters except for 6, 7, 11 o'clock-hour sectors.

CONCLUSIONS

RNFLT was found to be significantly thinner in APAC and unaffected fellow eyes when compared with normal age-matched controls. Hence, patients with APAC should be monitored carefully to determine its long-term effects on optic disc, RNFLT, and visual fields. Longitudinal studies can determine whether the RNFLT measurements remained stable or showed progression in these patients.

Association study in a South Indian population supports rs1015213 as a risk factor for primary angle closure

PURPOSE

Three loci defined by single nucleotide polymorphisms (SNPs) rs11024102 in PLEKHA7, rs3753841 in COL11A1, and rs1015213 between the PCMTD1 and ST18 genes, recently have been associated with primary angle closure glaucoma (PACG). We explored the genetic association of these SNPs with subtypes of primary angle closure in a South Indian population.

METHODS

The study included three case definitions: primary angle closure/primary angle closure glaucoma (PAC/PACG, N = 180); primary angle closure suspect (PACS, N = 171), and a combined any-angle closure group. Controls consisted of 411 individuals from South India. Genotyping for all three SNPs was performed using the TaqMan allelic discrimination assay. Genetic association was estimated using a χ(2) test statistics and logistic regression.

RESULTS

Among the three studied SNPs, significant genetic association was identified for rs1015213 in the PAC/PACG (P = 0.002) and any-angle closure (P = 0.003) analyses. However, no significant genetic association was seen when in PACS subjects (P = 0.052). SNPs rs3753841 and rs11024102 showed no evidence of genetic association with angle-closure phenotypes (P > 0.05) in South Indian participants.

CONCLUSIONS

In our study, rs1015213 (located in the intergenic region between PCMTD1 and ST18) was associated significantly with PAC/PACG, confirming prior reports of an association between this region and angle closure glaucoma. Further work with a larger sample size is necessary to confirm the importance of COL11A1 and PLEKHA7 in the pathogenesis of glaucoma.

Immediate changes in intraocular pressure after laser peripheral iridotomy in primary angle-closure suspects

PURPOSE

To determine the immediate changes in intraocular pressure (IOP) after laser peripheral iridotomy in primary angle-closure suspects.

DESIGN

Prospective, randomized controlled trial (split-body design).

PARTICIPANTS

Seven hundred thirty-four Chinese people 50 to 70 years of age.

METHODS

Primary angle-closure suspects underwent iridotomy using a neodymium:yttrium-aluminum-garnet laser in 1 randomly selected eye, with the fellow eye serving as a control. Intraocular pressure was measured using Goldmann applanation tonometry before treatment and 1 hour and 2 weeks after treatment. Total energy used and complications were recorded. Risk factors for IOP rise after laser peripheral iridotomy were investigated.

MAIN OUTCOME MEASURES

Intraocular pressure.

RESULTS

The proportion of treated eyes with an IOP spike (an elevation of ≥8 mmHg more than baseline) at 1 hour and 2 weeks after treatment was 9.8% (95% confidence interval [CI], 7.7-12.0) and 0.82% (95% CI, 0.2-1.5), respectively. Only 4 (0.54%) of 734 eyes (95% CI, 0.01-1.08) had an immediate posttreatment IOP of 30 mmHg or more and needed medical intervention. The average IOP 1 hour after treatment was 17.5±4.7 mmHg in the treated eyes, as compared with 15.2±2.6 mmHg in controls. At 2 weeks after treatment, these values were 15.6±3.4 mmHg in treated eyes and 15.1±2.7 mmHg in controls (P<0.001). No significant difference was detected in the baseline IOP of the treated and untreated eyes. Logistic regression showed that the incidence of IOP spike was associated with greater laser energy used and shallower central anterior chamber.

CONCLUSIONS

Laser peripheral iridotomy in primary angle-closure suspects resulted in significant IOP rise in 9.8% and 0.82% of cases at 1 hour and 2 weeks, respectively. Eyes in which more laser energy and a higher number of laser pulses were used and those with shallower central anterior chambers were at increased risk for IOP spikes at 1 hour after laser peripheral iridotomy.

Glaucoma

Most medical practitioners have regular contact with adults who have one of the two forms of glaucoma: open-angle glaucoma or angle-closure glaucoma. Data from population-based surveys indicate that one in 40 adults older than 40 years has glaucoma with loss of visual function, which equates to 60 million people worldwide being affected and 8·4 million being bilaterally blind. Even in developed countries, half of glaucoma cases are undiagnosed. Glaucoma is mostly asymptomatic until late in the disease when visual problems arise. Vision loss from glaucoma cannot be recovered, and improved case-detection methods for glaucoma are needed. Glaucoma is commonly treated with daily eye-drop drugs, but adherence to treatment is often unsatisfactory. As a usually asymptomatic and chronic disease, glaucoma has similar treatment challenges to chronic systemic diseases. Similarities to the pathogenesis of common CNS diseases mean that common neuroprotective strategies might exist. Successful gene therapy, which has been used for other eye diseases might be possible for the treatment of glaucoma in the future.

Optical coherence tomography quantitative analysis of iris volume changes after pharmacologic mydriasis

PURPOSE

To describe a method using anterior segment optical coherence tomography (AS OCT) for estimating iris volume. To quantify changes in iris volume induced by pharmacologic mydriasis in narrow-angle eyes predisposed to angle-closure compared with normal open-angle eyes.

DESIGN

Cross-sectional study.

PARTICIPANTS

Thirty fellow eyes of 30 patients who had an episode of primary acute angle-closure and 30 eyes of 30 normal age- and gender-matched subjects with open angles. All fellow eyes had a patent laser peripheral iridotomy.

METHODS

Iris volume and all biometric measurements were performed before and after instillation of 1% tropicamide and at least 1 week later 10% phenylephrine. Iris volume was estimated using AS OCT radial sections of the iris and a customized image-processing software.

MAIN OUTCOME MEASURES

Iris volume, pupil diameter, angle configuration including angle opening distance at 500 mum (AOD 500) and trabecular-iris space at 500 mum (TISA 500), AS OCT anterior chamber depth, and A-scan ultrasonography axial length before and after pupil dilation.

RESULTS

Iris volumes measured before dilation of the pupil were 44.94+/-2.1 mm(3) and 44.29+/-3.9 mm(3) in the fellow eyes and open-angle eyes, respectively, which was not significantly different (P>0.1). Thirty minutes after instillation of 1% tropicamide, mean iris volume increased significantly in the fellow eyes (from 44.94+/-2.1 mm(3) to 49.92+/-2.9 mm(3); P<0.01), whereas it decreased significantly in the open-angle eyes (from 44.29+/-3.9 mm(3) to 37.88+/-2.2 mm(3); P<0.01). Similar changes were observed after instillation of 10% phenylephrine. Based on multivariate analysis, significant predictors of increase in iris volume after pupil dilation were eyes predisposed to angle-closure compared with open-angle eyes (P = 0.008), larger pupil diameter (P = 0.02), and brown eyes (P = 0.01). Relative iris volume increase was correlated significantly with AOD 500 and TISA 500 relative decrease in the narrow-angle group (P<0.05).

CONCLUSIONS

The iris volume may be estimated with AS OCT. The iris volume increases after pupil dilation in narrow-angle eyes predisposed to acute angle closure. In those patients, this biometric change is associated with a narrowing of the angle despite a patent laser peripheral iridotomy.

FINANCIAL DISCLOSURE(S)

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

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.

Current Understanding of the Treatment and Outcome of Acute Primary Angle Closure Glaucoma: An Asian Perspective

Introduction: Primary angle-closure glaucoma (PACG) is a major cause of blindness among Asians. A better understanding of the disease will improve the treatment and outcome of this condition. Methods: A literature review of all recent publications on PACG was carried out. Articles were retrieved using a key word search of MEDLINE, PubMed and Science Citation Index databases. Results: Following laser peripheral iritodomy for acute angle-closure, Asians were found to have a higher tendency to develop a subsequent rise in intraocular pressure compared to Caucasians. Furthermore, the extent and severity of visual field damage was more severe in Asians than Caucasians, particularly in eyes that presented insidiously with chronic PACG. Prophylactic laser iridotomy in the contralateral eye was found to be highly effective in preventing acute angle-closure attacks. Conclusion: PACG is more difficult to manage and is associated with more severe long-term visual morbidity in Asians than Caucasians. Regular follow-up of patients with PACG is important for the early detection of progression of the disease and visual field deterioration.