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Dive into the research topics where Yolanda Y.Y. Kwong is active.

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Featured researches published by Yolanda Y.Y. Kwong.


Ophthalmology | 2008

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

Clement C.Y. Tham; Yolanda Y.Y. Kwong; Dexter Y.L. Leung; Sze-Wing Lam; Felix C.H. Li; Thomas Y. H. Chiu; Jonathan Cheuk Hung Chan; Dennis S.C. Lam; Jimmy S. M. Lai

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.


Ophthalmology | 2008

Randomized Trial of Early Phacoemulsification versus Peripheral Iridotomy to Prevent Intraocular Pressure Rise after Acute Primary Angle Closure

Dennis S.C. Lam; Dexter Y.L. Leung; Clement C.Y. Tham; Felix C.H. Li; Yolanda Y.Y. Kwong; Thomas Y. H. Chiu

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 <or= 21 mmHg was significantly higher in the LPI group (0.90+/-1.14) than in the phacoemulsification group (0.03+/-0.18, P<0.0001). Mean IOP for phacoemulsification group (12.6+/-1.9 mmHg) was consistently lower than that of the LPI group (15.0+/-3.4 mmHg, P = 0.009). Mean Shaffer grading for the phacoemulsification group (2.10+/-0.76) was consistently greater than that of the LPI group (0.73+/-0.64, P<0.0001). CONCLUSION Early phacoemulsification appeared to be more effective in preventing IOP rise than LPI in patients after abortion of APAC. High presenting IOP of >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.


Ophthalmology | 2013

Phacoemulsification versus Trabeculectomy in Medically Uncontrolled Chronic Angle-Closure Glaucoma without Cataract

Clement C.Y. Tham; Yolanda Y.Y. Kwong; Nafees Baig; Dexter Y.L. Leung; Felix C.H. Li; Dennis S.C. Lam

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.


Archives of Ophthalmology | 2010

Phacoemulsification vs phacotrabeculectomy in chronic angle-closure glaucoma with cataract complications

Clement C.Y. Tham; Yolanda Y.Y. Kwong; Dexter Y. L. Leung; Sze Wing Lam; Felix C.H. Li; Thomas Y. H. Chiu; Jonathan C.H. Chan; Dennis S.C. Lam; Jimmy S. M. Lai

OBJECTIVE To compare the complications of phacoemulsification alone vs combined phacotrabeculectomy in chronic angle-closure glaucoma (CACG) with coexisting cataract. METHODS Patients with CACG with coexisting cataract recruited into 2 randomized controlled trials comparing phacoemulsification alone vs combined phacotrabeculectomy were pooled for analysis. The first trial recruited patients with medically controlled intraocular pressure, while the second trial recruited patients with medically uncontrolled intraocular pressure. The 2 trials had otherwise identical study designs. All patients were reviewed every 3 months for 2 years after surgery. The main outcome measure was the surgical complications of phacoemulsification alone vs combined phacotrabeculectomy in CACG eyes with cataract. RESULTS One hundred twenty-three CACG eyes with cataract from 123 patients were included. Sixty-two CACG eyes were randomized to receive phacoemulsification alone, and 61 eyes had combined phacotrabeculectomy. In the phacoemulsification group, 5 of the 62 CACG eyes (8.1%) had a total of 5 surgical complications. In the combined phacotrabeculectomy group, 16 of the 61 CACG eyes (26.2%) had a total of 19 surgical complications. The difference in the proportion of eyes with 1 or more surgical complications between the 2 treatment groups was statistically significant (P = .007, Pearson chi(2) test). There was no statistically significant difference in final visual acuity or glaucomatous progression during the 24-month follow-up. CONCLUSIONS Combined phacotrabeculectomy resulted in significantly more surgical complications than phacoemulsification alone in CACG eyes with coexisting cataract. There was no difference in visual acuity or disease progression between the 2 treatment groups.


Journal of Glaucoma | 2010

Effects of phacoemulsification versus combined phaco-trabeculectomy on drainage angle status in primary angle closure glaucoma (PACG)

Clement C.Y. Tham; Dexter Y. L. Leung; Yolanda Y.Y. Kwong; Felix C.H. Li; Jimmy S. M. Lai; Dennis S.C. Lam

PurposeTo document anatomic effects of phacoemulsification versus combined phaco-trabeculectomy on drainage angle in primary angle closure glaucoma (PACG). MethodsIndentation gonioscopy and ultrasound biomicroscopy were performed preoperatively, and then at 1 year after phacoemulsification alone or combined phaco-trabeculectomy in PACG patients. ResultsSeventy-two PACG eyes of 72 patients were included in this study. Thirty-eight eyes were randomized into receiving phacoemulsification alone, whereas 34 eyes had combined phaco-trabeculectomy. The mean extent of synechial angle closure was significantly reduced from 266.4° to 198.9° (P<0.001) by phacoemulsification alone, and from 266.0° to 227.2° (P=0.03) by combined surgery. The mean angle opening distance (AOD 500) measured by ultrasound biomicroscopy was significantly increased from 208.0 to 468.0 μm (P<0.001) by phacoemulsification, and from 214.6 to 344.4 μm (P<0.001) by combined surgery. The mean trabecular-ciliary process distance was significantly increased from 824.6 to 1043.6 μm (P<0.001) by phacoemulsification, and from 800.9 to 951.5 μm (P=0.01) by combined surgery. The mean anterior chamber depth was significantly increased from 1798.6 to 3528.4 μm (P<0.001) by phacoemulsification alone, and from 1781.6 to 3297.8 μm (P<0.001) by combined surgery. Phacoemulsification alone resulted in significantly greater postoperative angle opening distance 500 (P<0.001) and anterior chamber depth (P<0.001) than phaco-trabeculectomy. ConclusionsPhacoemulsification alone resulted in greater opening of drainage angle and greater deepening of anterior chamber than combined phaco-trabeculectomy in PACG eyes. SynopsisPhacoemulsification alone resulted in greater opening of drainage angle and greater deepening of anterior chamber than combined phaco-trabeculectomy in PACG eyes.


Ophthalmology | 2010

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

Dexter Y.L. Leung; Felix C.H. Li; Yolanda Y.Y. Kwong; Clement C.Y. Tham; Stanley C.C. Chi; Dennis S.C. Lam

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 Andersons 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.


Ophthalmology | 2009

Silent Cerebral Infarct and Visual Field Progression in Newly Diagnosed Normal-Tension Glaucoma: A Cohort Study

Dexter Y.L. Leung; Clement C.Y. Tham; Felix C.H. Li; Yolanda Y.Y. Kwong; Stanley C.C. Chi; Dennis S.C. Lam

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 Andersons 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.


Journal of Glaucoma | 2006

Effect of a previous acute angle closure attack on the corneal endothelial cell density in chronic angle closure glaucoma patients.

Clement C.Y. Tham; Yolanda Y.Y. Kwong; Jimmy S. M. Lai; Dennis S.C. Lam

PurposeTo document the effect of a previous acute angle closure attack on the corneal endothelial cell density in chronic angle closure glaucoma (CACG) patients. MethodsConsecutive cases of CACG with patent peripheral iridotomy had their central corneal endothelial cell density measured by specular microscopy. The corneal endothelial cell density of those CACG eyes with a previous documented acute angle closure attack were compared with those eyes without such a history, to determine the effect of a previous acute angle closure attack on corneal endothelial cell density. ResultsFrom July 2003 to July 2005, a total of 52 CACG eyes of 52 patients fulfilling the study criteria were recruited. Thirteen eyes (25%) had a previous documented acute angle closure attack, whereas 39 eyes (75%) did not. The mean central corneal endothelial cell density ±1 standard deviation was 2271.7±312.9 (range, 1556 to 2661) cells/mm2 in those CACG eyes with previous acute angle closure, and 2570.0±429.9 (range, 1669 to 3861) cells/mm2 in those CACG eyes without previous acute angle closure (P<0.05, Student t test). A previous acute angle closure attack in a CACG eye correlates with a 11.6% reduction in corneal endothelial cell density, compared with a CACG eye without such a history. There were no statistically significant differences between the 2 groups in age, LogMAR visual acuity, intraocular pressure, number of glaucoma eye drops, vertical cup-to-disk ratio, mean deviation or pattern standard deviation in Humphrey automated perimetry (P>0.05). ConclusionsA previous acute angle closure attack correlates with a significantly reduced corneal endothelial cell density in CACG patients.


Eye | 2006

Intrableb triamcinolone acetonide injection after bleb-forming filtration surgery (trabeculectomy, phacotrabeculectomy, and trabeculectomy revision by needling): a pilot study

C C Y Tham; Felix Chi‐hong Li; D Y L Leung; Yolanda Y.Y. Kwong; Doris W.F. Yick; C C Chi; Dennis S.C. Lam

Intrableb triamcinolone acetonide injection after bleb-forming filtration surgery (trabeculectomy, phacotrabeculectomy, and trabeculectomy revision by needling): a pilot study


Japanese Journal of Ophthalmology | 2006

Canaliculitis Associated with a Combined Infection of Lactococcus lactis cremoris and Eikenella corrodens

Dexter Y.L. Leung; Yolanda Y.Y. Kwong; C. H. Ma; W. M. Wong; Dennis S.C. Lam

Bacteria of the genus Lactococcus are Gram-positive and generally are recognized as nonpathogenic to humans. To the best of our knowledge, this genus has not been reported in human ocular infections. Eikenella corrodens is a slowly growing, facultatively anaerobic and Gram-negative bacillus. A rare case of canaliculitis associated with Eikenella corrodens has been reported. Here we present an unusual case of canaliculitis associated with a mixed infection by both organisms.

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Dive into the Yolanda Y.Y. Kwong's collaboration.

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Dennis S.C. Lam

The Chinese University of Hong Kong

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Clement C.Y. Tham

The Chinese University of Hong Kong

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Felix C.H. Li

The Chinese University of Hong Kong

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Dexter Y.L. Leung

The Chinese University of Hong Kong

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Nafees Baig

The Chinese University of Hong Kong

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Thomas Y. H. Chiu

The Chinese University of Hong Kong

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C C Y Tham

The Chinese University of Hong Kong

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D Y L Leung

The Chinese University of Hong Kong

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Hunter K. L. Yuen

The Chinese University of Hong Kong

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