Normal-tension glaucoma: Current concepts and approaches-A review.

Normal tension glaucoma (NTG) has remained a challenging disease. We review, from an epidemiological perspective, why we should redefine normality, act earlier at lower pre-treatment intraocular pressure (IOP) level, and the role of ocular perfusion pressures, noting that perfusion is affected by defective vascular bed autoregulation and endothelial dysfunction. The correlation of silent cerebral infarcts (SCI) and NTG may indicate that NTG belongs to a wider spectrum of small vessel diseases (SVD), with its main pathology being also on vascular endothelium. Epidemiological studies also suggested that vascular geometry, such as fractal dimension, may affect perfusion efficiency, occurrence of SCI, SVD and glaucoma. Artificial intelligence with deep learning, may help predicting NTG progression from vascular geometry. Finally, we review latest evidence on the role of minimally-invasive glaucoma surgery, lasers, and newer drugs. We conclude that IOP is not the only modifiable risk factors as, many vascular risk factors are readily modifiable.

Anatomical effects of clear lens extraction by phacoemulsification versus trabeculectomy on anterior chamber drainage angle in primary angle-closure glaucoma (PACG) patients.

PURPOSE: To document the anatomical effects of clear lens extraction by phacoemulsification versus trabeculectomy on anterior chamber angle in patients with primary angle-closure glaucoma (PACG). METHODS: Gonioscopy and ultrasound biomicroscopy (UBM) were performed pre-operatively, and at 1 year after clear lens extraction or trabeculectomy in PACG eyes. RESULTS: Fifty PACG eyes of 50 patients were included. Twenty-six eyes had clear lens extraction by phacoemulsification, while 24 eyes underwent trabeculectomy. The mean extent of synechial angle closure was significantly reduced from 272.3° ± 57.3° to 253.3° ± 70.5° (p = 0.007) by phacoemulsification, but it was only reduced from 285.0° ± 64.6° to 283.1° ± 55.5° (p = 0.32) by trabeculectomy. The mean angle-opening distance at 500 microns from sclera spur (AOD500) measured by UBM was significantly increased from 220.3 ± 93.8 microns to 388.9 ± 134.1 microns (p < 0.001) by clear lens extraction, but decreased from 220.9 ± 79.8 microns to 214.5 ± 70.2 microns (p = 0.11) by trabeculectomy. The mean anterior chamber depth (ACD) measured by UBM was significantly increased from 1,983.8 ± 176.8 microns to 3335.0 ± 174.2 microns (p < 0.001) by clear lens extraction, but decreased from 2,000.2 ± 214.5 microns to 1975.8 ± 218.2 microns (p = 0.001) by trabeculectomy. CONCLUSION: Compared to trabeculectomy, clear lens extraction resulted in a significant reduction in synechial angle closure, and an increase in anterior chamber angle width and anterior chamber depth in PACG eyes without cataract.

Progressive peripapillary capillary vessel density loss and long-term visual field progression in Normal tension glaucoma.

PURPOSE: To explore the association between progressive peripapillary capillary vessel density (pcVD) reduction and the progression of visual field (VF) impairment in individuals with normal tension glaucoma (NTG). DESIGN: Prospective cohort study. METHODS: The study enrolled 110 participants with one eye each, totalling 110 NTG eyes. VF defects were evaluated using standard automated perimetry mean deviation (MD), while pcVD measurements were obtained using optical coherence tomography angiography throughout the follow-up period. Estimates of VF progression were determined by event-based and trend-based analyses. Fast VF progression was defined as an MD slope steeper than -0.5 dB/year, while the slow progression or stable VF was defined as an MD slope better or equal to -0.25 dB/year. Linear mixed-effects models were employed to analyse the rates of change in pcVD reduction and VF MD decline over time. Additionally, univariable and multivariable linear models were used to examine the relationship between pcVD changes and VF loss rates in NTG. RESULTS: Slow VF progression or stable VF was observed in 45% of subjects, while 25% had moderate progression and 30% showed fast progression. Patients with VF progression exhibited faster rate of pcVD reduction in peripapillary global region (-0.73 ± 0.40%/year vs. -0.56 ± 0.35%/year, p = 0.022). Moreover, this rate positively correlated with VF MD decline in NTG (estimate 0.278, 95% CI 0.122-0.433, p = 0.001). CONCLUSION: In individuals with NTG, faster VF progression was linked to a quicker reduction in pcVD, suggesting a positive correlation between pcVD decline and VF deterioration.

Natural History and Risk Factors for Glaucoma Progression in Chinese Patients With Normal-Tension Glaucoma.

Purpose: To characterize the natural history of normal-tension glaucoma (NTG) in Chinese patients. Methods: The prospective observational cohort study included patients with untreated NTG with a minimum follow-up of 2 years. Functional progression was defined by visual field (VF) deterioration, while structural progression was characterized by thinning of the retinal nerve fiber layer (RNFL) or ganglion cell inner plexiform layer (GCIPL). Results: Among 84 participants (mean age, 60.5 years; mean deviation, -5.01 decibels [dB]) with newly diagnosed NTG followed for an average of 69.7 months, 63.1% progressed during the observation period. Specifically, 29.8% progressed by VF, and 48.8% progressed by either RNFL or GCIPL. In Cox proportional hazards analysis, disc hemorrhage (hazard ratio [HR], 2.82; 95% confidence interval [CI], 1.48-5.35), female gender (HR, 1.98; 95% CI, 1.08-3.62), and mean IOP during the follow-up period (HR, 1.14 per mm Hg; 95% CI, 1.00-1.31) were significant predictors of glaucomatous progression. Additionally, longer axial length (AL; HR, 0.57 per millimeter; 95% CI, 0.35-0.94) was protective against VF progression faster than -0.50 dB/y, and higher minimum diastolic blood pressure (DBP; HR, 0.96 per mm Hg; 95% CI, 0.92-1.00) was protective against structural progression. Conclusions: Nearly two-thirds of untreated Chinese patients with NTG progressed over an average follow-up of 70 months by VF, RNFL, or GCIPL. Disc hemorrhage, female gender, higher mean IOP, shorter AL, and lower minimum DBP were significant predictors for disease progression.

Phacoemulsification versus trabeculectomy in medically uncontrolled chronic angle-closure glaucoma without cataract.

OBJECTIVE: To compare phacoemulsification versus trabeculectomy with adjunctive mitomycin C in medically uncontrolled chronic angle-closure glaucoma (CACG) without cataract. DESIGN: Prospective, randomized clinical trial. PARTICIPANTS: Fifty medically uncontrolled CACG eyes without cataract of 50 patients. INTERVENTION: Patients were randomized into undergoing either phacoemulsification or trabeculectomy with adjunctive mitomycin C. After surgery, patients were followed up every 3 months for 2 years. MAIN OUTCOME MEASURES: Intraocular pressure (IOP) and requirement for glaucoma drugs. RESULTS: Twenty-six CACG eyes were randomized to receive phacoemulsification, and 24 eyes underwent trabeculectomy with mitomycin C. Phacoemulsification and trabeculectomy resulted in significant and comparable IOP reduction at 24 months after surgery (reduction of 8.4 mmHg or 34% for phacoemulsification vs. 8.9 mmHg or 36% for trabeculectomy; P=0.76). Over first 24 months, trabeculectomy-treated eyes required on average 1.1 fewer drugs than phacoemulsification-treated eyes (P<0.001). However, trabeculectomy was associated with significantly more surgical complications than phacoemulsification (46% vs. 4%; P=0.001). Eight (33%) of 24 trabeculectomy eyes demonstrated cataract during follow-up. CONCLUSIONS: Both phacoemulsification and trabeculectomy are effective in reducing IOP in medically uncontrolled CACG eyes without cataract. Trabeculectomy is more effective than phacoemulsification in reducing dependence on glaucoma drugs, but is associated with more complications. FINANCIAL DISCLOSURE(S): The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Risk of Normal Tension Glaucoma Progression From Automated Baseline Retinal-Vessel Caliber Analysis: A Prospective Cohort Study.

PURPOSE: To determine the relationship between baseline retinal-vessel calibers computed by a deep-learning system and the risk of normal tension glaucoma (NTG) progression. DESIGN: Prospective cohort study. METHODS: Three hundred and ninety eyes from 197 patients with NTG were followed up for at least 24 months. Retinal-vessel calibers (central retinal arteriolar equivalent [CRAE] and central retinal venular equivalent [CRVE]) were computed from fundus photographs at baseline using a previously validated deep-learning system. Retinal nerve fiber layer (RNFL) thickness and visual field (VF) were evaluated semiannually. The Cox proportional-hazards model was used to evaluate the relationship of baseline retinal-vessel calibers to the risk of glaucoma progression. RESULTS: Over a mean follow-up period of 34.36 ± 5.88 months, 69 NTG eyes (17.69%) developed progressive RNFL thinning and 22 eyes (5.64%) developed VF deterioration. In the multivariable Cox regression analysis adjusting for age, gender, intraocular pressure, mean ocular perfusion pressure, systolic blood pressure, axial length, standard automated perimetry mean deviation, and RNFL thickness, narrower baseline CRAE (hazard ratio per SD decrease [95% confidence interval], 1.36 [1.01-1.82]) and CRVE (1.35 [1.01-1.80]) were associated with progressive RNFL thinning and narrower baseline CRAE (1.98 [1.17-3.35]) was associated with VF deterioration. CONCLUSION: In this study, each SD decrease in the baseline CRAE or CRVE was associated with a more than 30% increase in the risk of progressive RNFL thinning and a more than 90% increase in the risk of VF deterioration during the follow-up period. Baseline attenuation of retinal vasculature in NTG eyes was associated with subsequent glaucoma progression. High-throughput deep-learning-based retinal vasculature analysis demonstrated its clinical utility for NTG risk assessment.

Evaluation of NTF4 as a causative gene for primary open-angle glaucoma.

PURPOSE: The neurotrophin-4 (NTF4) gene has been recently implicated in primary open-angle glaucoma (POAG). In this study, we investigated the implication of NTF4 in POAG among three Chinese cohorts. METHODS: The coding regions and exon-intron boundaries of NTF4 was sequenced in 950 unrelated Chinese subjects, including a Hong Kong cohort of 390 patients and 230 controls, a Shantou cohort of 130 patients, and a Beijing cohort of 200 patients. Constructs carrying the detected variants were generated using site-directed mutagenesis and transfected into HeLa cells, followed by solubility and migration analyses. RESULTS: Three variants were identified. p.Pro151Pro was detected in three POAG patients and one control subject. Two novel missense variants, p.Gly157Ala and p.Ala182Val, were identified each in one POAG patient from the Hong Kong cohort, but not in controls. Functional assays showed that the p.Gly157Ala mutant protein was less soluble in Triton X-100, and that migration of HeLa cells transfected with either mutant construct was less than cells transfected with the wildtype. CONCLUSIONS: The NTF4 variants p.Gly157Ala and p.Ala182Val have been shown to be functional mutations, occurring in 2 of a total of 720 Chinese POAG patients. NTF4 is functionally related to POAG pathogenesis but its mutation frequency is low. Therefore, NTF4 does not have a major contribution in the molecular genetics of POAG.

SNP rs1533428 at 2p16.3 as a marker for late-onset primary open-angle glaucoma.

PURPOSE: To investigate the associations between gene variants in cholesterol 24S-hydroxylase (CYP46A1), LIM homeobox transcription factor 1-beta (LMX1B), plexin domain containing 2 (PLXDC2), toll-like receptor 4 (TLR4), transmembrane and tetratricopeptide repeat containing 2 (TMTC2), zona pellucida glycoprotein 4 (ZP4), chromosome 2p16.3, and primary open-angle glaucoma (POAG). METHODS: We studied 462 POAG patients and 577 controls from three cohorts (Hong Kong, Shantou, and Beijing, China). Twelve single-nucleotide polymorphisms (SNPs) were genotyped in the Hong Kong cohort using TaqMan genotyping assay. Significant associations were validated in the Shantou and Beijing cohorts. RESULTS: Association of POAG with TLR4 rs7037117, in a recessive model, was identified in the Hong Kong and Shantou cohorts (both southern Chinese, p(rec)=0.0019) but not the Beijing cohort (northern Chinese). rs1533428 at chromosome 2p16.3 showed a consistent trend of age-specific association in all three cohorts. Genotypes TT + CT conferred a 2.16 fold of significantly increased risk to late-onset POAG (p(dom)=0.00025), but no significant risk to POAG of younger ages of onset in the combined cohort. A joint effect was found between rs7037117 and rs1533428, with carriers of both higher-risk genotypes having a 4.53 fold of increased disease risk (p=0.00028). CONCLUSIONS: Our study reveals discrepant association patterns of 12 candidate SNPs in 7 genes/loci with POAG in Chinese, provides positive replications for POAG markers rs1533428 at 2p16.3 and TLR4 rs7037117, and suggests that rs1533428 is a putative risk variant for late-onset POAG. The identification of an age-specific association between rs1533428 and late-onset POAG highlights a new genotype-phenotype association in POAG. Further studies are warranted to confirm the age-specific association.

Simvastatin and disease stabilization in normal tension glaucoma: a cohort study.

PURPOSE: To investigate whether simvastatin use is associated with visual field (VF) stabilization in patients with normal tension glaucoma (NTG). DESIGN: Prospective cohort study (ClinicalTrials.gov Identifier: NCT00321386). PARTICIPANTS: A total of 256 eyes from 256 Chinese subjects with NTG. METHODS: Patients were followed up at 4-month intervals for 36 months for VF progression per Anderson's criteria. Clinical parameters were checked for association with progression in multivariate analysis. MAIN OUTCOME MEASURES: The primary outcome was the association between simvastatin use and VF progression. RESULTS: Thirty-one patients (12.1%) were taking simvastatin (statin+), and 225 patients (87.9%) were not taking simvastatin (statin-). Baseline age, gender, untreated intraocular pressure, VF indices, vertical cup-to-disc ratio, and central corneal thickness (CCT) were comparable between the 2 groups. There were significantly more patients with a history of hypercholesterolemia, systemic hypertension, and ischemic heart disease in the statin+ group. A total of 121 patients (47.3%) showed evidence of VF progression (mean rate of mean deviation loss was -0.30 decibel per year) during the 36 months of follow-up. Simvastatin use was among 8 of 121 patients (6.6%) who progressed compared with 23 of 135 patients (17.0%) who did not progress (P = 0.011). Logistic regression revealed that history of disc hemorrhage (relative risk [RR] 3.26; 95% confidence interval [CI], 1.21-8.76; P = 0.019), history of cerebrovascular accidents (RR 2.28; 95% CI, 1.03-5.06; P = 0.043), and baseline age (per 10 years older; RR 1.38; 95% CI, 1.08-1.76; P = 0.009) were significant risk factors for VF progression, whereas simvastatin use conferred a protective effect (RR 0.36; 95% CI, 0.14-0.91; P = 0.030). CONCLUSIONS: Simvastatin use may be associated with VF stabilization in patients with NTG. A larger scale randomized controlled trial and cost-effectiveness analyses seem warranted.

Global assessment of arteriolar, venular and capillary changes in normal tension glaucoma.

Microcirculatory insufficiency has been hypothesized in glaucoma pathogenesis. There is a scarcity of data to comprehensively examine the changes in retinal microvasculature and its role in normal tension glaucoma (NTG). We conducted a cross-sectional case-control study and included 168 eyes from 100 NTG patients and 68 healthy subjects. Quantitative retinal arteriolar and venular metrics were measured from retinal photographs using a computer-assisted program. Radial peripapillary capillary network was imaged with OCT-A and quantitative capillary metrics (circumpapillary vessel density (cpVD) and circumpapillary fractal dimension (cpFD)) were measured with a customized MATLAB program. We found that NTG was associated with decreased arteriolar and venular tortuosity, arteriolar branching angle, cpVD and cpFD. Decreased venular caliber, arteriolar and venular branching angles, cpVD and cpFD were associated with thinner average RNFL thickness. Decreased arteriolar and venular branching angles, cpVD and cpFD were also associated with worse standard automated perimetry measurements (mean deviation and visual field index). Compared with retinal arteriolar and venular metrics, regression models based on OCT-A capillary metrics consistently showed stronger associations with NTG and structural and functional measurements in NTG. We concluded that NTG eyes showed generalized microvascular attenuations, in which OCT-A capillary metrics attenuations were more prominent and strongly associated with NTG.

Silent cerebral infarct and visual field progression in newly diagnosed normal-tension glaucoma: a cohort study.

PURPOSE: To investigate whether the presence of silent cerebral infarct (SCI) is related to field progression in patients with newly diagnosed normal-tension glaucoma (NTG). DESIGN: Prospective cohort study. PARTICIPANTS: A total of 286 eyes from 286 NTG patients: 64 with SCI (SCI+) and 222 without SCI (SCI-). METHODS: Patients were assigned to the SCI+ or SCI- group depending on the presence of SCI as detected by cranial computed tomography scan at baseline. Patients were followed-up at 4-month intervals for 36 months for visual field progression as per Anderson's criteria. MAIN OUTCOME MEASURES: The primary outcome was the association between SCI and field progression. Secondary outcomes include the prevalence of SCI in NTG patients and other risk factors associated with progression. RESULTS: There were no significant differences in the baseline intraocular pressures (IOPs), fluctuation amplitude of pretreatment IOP, baseline visual acuity, vertical cup-to-disc ratio, vertical disc diameter, presenting field indices, and central corneal thickness (CCT) between the 2 groups. Patients with SCI were significantly older compared with SCI- patients (72.4+/-10.7 vs. 63.2+/-14.2 years; P<0.001). Univariate analyses revealed age, fluctuation amplitude of pretreatment IOP, thinner CCT, presence of disc hemorrhage, systemic hypertension, arrhythmia, and SCI were significant for field progression. Silent cerebral infarct was present in 29.6% of field-progressed subjects versus 15.3% of field-stable subjects (P = 0.004). Kaplan-Meier survival analysis revealed that 65.6% of SCI+ versus 45.9% of SCI- patients had progressed (P = 0.003). Cox proportional hazards regression analysis showed disc hemorrhage (hazard ratio [HR], 2.28; 95% confidence interval [CI], 1.54-3.37; P<0.001), SCI (HR, 1.61; 95% CI, 1.09-2.36; P = 0.016), systemic hypertension (HR, 1.48; 95% CI, 1.04-2.10; P = 0.029), and CCT (per 30 mum of thinning; HR, 1.35; 95% CI, 1.16-1.75; P<0.001) were associated with field progression. Other variables significant in the univariate analysis were not significant in the regression model. The most common location of SCI was at the basal ganglia. CONCLUSIONS: Presence of SCI may be an independent risk factor for visual field progression in patients with NTG.

Phacoemulsification versus combined phacotrabeculectomy in medically uncontrolled chronic angle closure glaucoma with cataracts.

OBJECTIVE: To compare phacoemulsification alone versus combined phacotrabeculectomy in medically uncontrolled chronic angle closure glaucoma (CACG) with coexisting cataract. DESIGN: Prospective randomized clinical trial. PARTICIPANTS: Fifty-one medically uncontrolled CACG eyes with coexisting cataract of 51 patients. INTERVENTION: Recruited patients were randomized into group 1 (phacoemulsification alone) or group 2 (combined phacotrabeculectomy with adjunctive mitomycin C). Postoperatively, patients were reviewed every 3 months for 2 years. MAIN OUTCOME MEASURES: Intraocular pressure (IOP) and requirement for topical glaucoma drugs. RESULTS: Twenty-seven CACG eyes were randomized into group 1, and 24 CACG eyes were randomized into group 2. Combined phacotrabeculectomy resulted in lower mean postoperative IOP than phacoemulsification alone at 3 months (14.0 vs. 17.0 mmHg, P = 0.01), 15 months (13.2 vs. 15.4 mmHg, P = 0.02), and 18 months (13.6 vs. 15.9 mmHg, P = 0.01). Combined phacotrabeculectomy resulted in 1.25 fewer topical glaucoma drugs (P<0.001) in the 24-month postoperative period, compared with phacoemulsification alone. Combined surgery was associated with more postoperative complications (P<0.001) and more progression of optic neuropathy (P = 0.03), compared with phacoemulsification alone. CONCLUSIONS: Combined phacotrabeculectomy with adjunctive mitomycin C is more effective than phacoemulsification alone in controlling IOP in medically uncontrolled CACG eyes with coexisting cataract. Combined phacotrabeculectomy is associated with more postoperative complications.

Evaluation of LOXL1 polymorphisms in primary open-angle glaucoma in southern and northern Chinese.

PURPOSE: The lysyl oxidase-like protein 1 (LOXL1) gene is strongly associated with exfoliation glaucoma, which is very rare in the Chinese population. The implicated LOXL1 polymorphisms have not been associated with primary open-angle glaucoma (POAG). In this study, we investigated three of the LOXL1 polymorphisms in POAG in a southern Chinese population of Hong Kong and northern Chinese from Beijing. METHODS: The Hong Kong group included 293 POAG patients and 250 controls, and the Beijing group included 169 POAG patients and 197 controls. LOXL1 single nucleotide polymorphisms (SNPs), rs1048661, rs3825942, and rs2165241, were genotyped by direct DNA sequencing. Individual association was analyzed using the chi(2) test, and haplotype-based association analysis was performed in WHAP. RESULTS: Each of the candidate SNPs was not statistically associated with POAG in either group (p>0.017, Bonferroni correction). Haplotype-based association analysis had identified a significant omnibus association (Omnibus chi(2)=18.16, p=0.00115) between these SNPs and POAG in the Hong Kong group. A minor haplotype (T-G-T) showed significant statistical association with POAG. It presented in 2.1% of cases and 0.4% of controls, conferring a 5.24 fold of increased risk to the disease (95% CI: 1.17-23.54, P(perm)=0.00108). However, this haplotype was absent in the Beijing group. CONCLUSIONS: Individual LOXL1 SNPs, rs1048661, rs3825942, and rs2165241, were not associated with POAG in the Chinese population. However, a minor haplotype T-G-T was found to be associated with the disorder in the southern Chinese. The low frequencies of the at-risk alleles at rs1048661 and rs2165241 may be one of the factors that led to the low prevalence of exfoliation syndrome in the general populations of the Chinese.

Randomized trial of early phacoemulsification versus peripheral iridotomy to prevent intraocular pressure rise after acute primary angle closure.

PURPOSE: To compare the efficacy of early phacoemulsification versus laser peripheral iridotomy (LPI) in the prevention of intraocular pressure (IOP) rise in patients after acute primary angle closure (APAC). DESIGN: Prospective randomized controlled trial. PARTICIPANTS: Sixty-two eyes of 62 Chinese subjects, with 31 eyes in each arm. METHODS: Subjects were randomized to receive either early phacoemulsification or LPI after aborting APAC by medications. Patients were followed up on day 1; week 1; and months 1, 3, 6, 12, and 18. Predictors for IOP rise were studied. MAIN OUTCOME MEASURES: Prevalence of IOP rise above 21 mmHg (primary) and number of glaucoma medications, IOP, and Shaffer gonioscopy grading (secondary). RESULTS: Prevalences of IOP rise for the LPI group were 16.1%, 32.3%, 41.9%, and 46.7% for the follow-ups at 3, 6, 12, and 18 months, respectively. There was only one eye (3.2%) in the phacoemulsification group that had IOP rise at all follow-up time points (P<0.0001). Treatment by LPI was associated with significantly increased hazard of IOP rise (hazard ratio [HR], 14.9; 95% confidence interval [CI], 1.9-114.2; P = 0.009). In addition, a maximum IOP at presentation > 55 mmHg was associated with IOP rise (HR, 4.1; 95% CI, 1.3-13.0; P = 0.017). At 18 months, the mean number of medications required to maintain IOP 55 mmHg is an added risk factor for subsequent IOP rise. For patients with coexisting cataract and presenting IOP of >55 mmHg, early phacoemulsification can be considered as a definitive treatment to prevent IOP rise.

Phacoemulsification versus combined phacotrabeculectomy in medically controlled chronic angle closure glaucoma with cataract.

OBJECTIVE: To compare phacoemulsification alone versus combined phacotrabeculectomy in medically controlled chronic angle closure glaucoma (CACG) with coexisting cataract. DESIGN: Randomized clinical trial. PARTICIPANTS: Seventy-two medically controlled CACG eyes with coexisting cataract. INTERVENTION: Recruited patients were randomized into group 1 (phacoemulsification alone) or group 2 (combined phacotrabeculectomy with adjunctive mitomycin C). Postoperatively, patients were reviewed every 3 months for 2 years. MAIN OUTCOME MEASURES: Intraocular pressure (IOP) and requirement for topical glaucoma drugs. RESULTS: Thirty-five CACG eyes were randomized into group 1, and 37 CACG eyes were randomized into group 2. There were no statistically significant differences (P>0.05) in mean IOP between the 2 treatment groups preoperatively and postoperatively, except at 1 month (P = 0.001) and 3 months (P = 0.008). Combined phacotrabeculectomy with adjunctive mitomycin C resulted in 0.80 less topical glaucoma drugs (P<0.001) in the 24-month postoperative period compared with phacoemulsification alone. The differences in IOP control were, however, not associated with differences in glaucomatous progression. Combined surgery was associated with more postoperative (P<0.001) complications compared with phacoemulsification alone. CONCLUSIONS: Combined phacotrabeculectomy with adjunctive mitomycin C may be marginally more effective than phacoemulsification alone in controlling IOP in medically controlled CACG eyes with coexisting cataract. Combined surgery may be associated with more complications and additional surgery in the postoperative period. Further study is needed to determine whether the marginally better IOP control of combined surgery justifies the potential additional risks of complications and further surgery. FINANCIAL DISCLOSURE(S): The authors have no proprietary or commercial interest in any materials discussed in this article.

Novel myocilin mutation in a Chinese family with juvenile-onset open-angle glaucoma.

OBJECTIVE: To search for the genetic cause of juvenile-onset open-angle glaucoma (JOAG) in a Chinese family. METHODS: In a 3-generation glaucoma family affected with JOAG or ocular hypertension, we screened myocilin (MYOC) and optineurin (OPTN) for mutations and investigated apolipoprotein E (APOE) polymorphisms in 6 family members, 2 of them patients with JOAG, 2 patients with ocular hypertension, and 2 patients who were asymptomatic. Normal controls included 200 unrelated Chinese subjects. The COS-7 cell line was transfected with expression vectors encoding wild-type or mutated MYOC complementary DNA. Cellular and secreted MYOC proteins were characterized by Western blotting. RESULTS: One missense MYOC mutation, 734G>A: Cys245Tyr, was identified. It occurred in all 4 family members afflicted with JOAG or ocular hypertension but not in asymptomatic family members. No OPTN variations were observed. APOE polymorphism frequencies were similar to those for controls. The Cys245Tyr MYOC mutation cosegregated with the disorder within the family. It was absent in the 200 control subjects. The Cys245Tyr mutant MYOC protein formed homomultimeric complexes that migrated at molecular weights larger than their wild-type counterparts. These mutant complexes remained sequestered intracellularly in COS-7 cells. CONCLUSIONS: The Cys245Tyr MYOC mutation was the genetic cause of JOAG in this Chinese family. This mutation may alter covalent bonds that formed between MYOC cysteines. Clinical Relevance Genetic tests of MYOC mutations may be beneficial to predict new cases of the disease in families with JOAG.