Publications by authors named "Tiffany T Y Woo"

8 Publications

  • Page 1 of 1

Comparison of two-year treatment outcomes between subthreshold micropulse (577 nm) laser and aflibercept for diabetic macular edema.

Jpn J Ophthalmol 2021 Jun 14. Epub 2021 Jun 14.

Department of Ophthalmology, Caritas Medical Centre, 111 Wing Hong Street, Sham Shui Po, Hong Kong.

Purpose: To compare two-year treatment outcomes of subthreshold micropulse (577 nm) laser and aflibercept for diabetic macular edema (DME).

Study Design: Retrospective case-control study.

Methods: A total 164 eyes in 164 DME patients treated with either micropulse laser (86 eyes) or intravitreal aflibercept monotherapy (78 eyes) were recruited. Main outcome measures included at least five Early Treatment Diabetic Retinopathy Study (ETDRS) letters' improvement from baseline at 6, 12 and 24 months.

Results: Rescue aflibercept was initiated in 24% of eyes in micropulse laser group. At 6-month visit the aflibercept group achieved a higher percentage of eyes with at least 5-letter visual acuity improvement than micropulse laser group (56% vs 38%, P = 0.044), however, this was not the case at 12-month (45% vs 49%, P = 0.584) and 24-month visits (49% vs 57%, P = 0.227). At 6-month visit the aflibercept group achieved a higher percentage of eyes with at least 10% improvement of central macular thickness (73% vs 49%, P = 0.005), but this was not the case at 12-month (73% vs 70%, P = 0.995) and 24-month visits (85% vs 84%, P = 0.872).

Conclusion: Aflibercept achieved faster and higher rates of anatomical and functional improvement than micropulse laser in DME patients. Long term efficacy of treatment did not result in significant differences between aflibercept monotherapy and micropulse laser in DME patients. Primary treatment of micropulse laser with deferred rescue aflibercept might be the treatment option without reducing the chance of visual improvement in DME eyes.
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http://dx.doi.org/10.1007/s10384-021-00846-4DOI Listing
June 2021

Central Macular Thickness in Children with Myopia, Emmetropia, and Hyperopia: An Optical Coherence Tomography Study.

Biomed Res Int 2015 8;2015:847694. Epub 2015 Jun 8.

Department of Ophthalmology, University of Hong Kong, Room 301, Level 3 Block B, Cyberport 4, 100 Cyberport Road, Hong Kong.

Purpose: To investigate the central macular thickness (CMT) in myopic, emmetropic, and hyperopic Chinese children using Optical Coherence Tomography.

Methods: 168 right eyes of Chinese subjects aged 4-18 were divided into 3 groups based on their postcycloplegic spherical equivalent: myopes (<-1.0 D); emmetropes (≥-1.0 to ≤+1.0 D); and hyperopes (>+1.0 D) and the CMT was compared before/after age adjustment. The CMT was correlated with age, axial length, and peripapillary retinal nerve fibre layer (RNFL).

Results: The mean CMT was 274.9 ± 50.3 μm and the mean population age was 7.6 ± 3.3 years. The CMT was thickest in the myopes (283.3 ± 57.3 μm, n = 56), followed by the hyperopes (266.2 ± 55.31 μm, n = 60) and then emmetropes (259.8 ± 28.7 μm, n = 52) (all P < 0.0001). When adjusted for age, myopes had a thicker CMT than the other 2 groups (all P < 0.0001) but there was no CMT difference between the emmetropes and hyperopes (P > 0.05). There was no significant correlation between CMT with age, axial length, or peripapillary RNFL (all P ≥ 0.2).

Conclusion: Chinese children with myopia had a thicker CMT than those with emmetropia or hyperopia. There was no correlation of the CMT with age, axial length, or peripapillary RNFL thickness.
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http://dx.doi.org/10.1155/2015/847694DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4475703PMC
April 2016

Retinal nerve fiber layer thickness in myopic, emmetropic, and hyperopic children.

Medicine (Baltimore) 2015 Mar;94(12):e699

From the Department of Ophthalmology (JWYL, GSKY, TTYW, DWFY, VTYT), Caritas Medical Centre; and Department of Ophthalmology (JWYL, JSML), The University of Hong Kong, Hong Kong Special Administrative Region, China.

The purpose of this study was to investigate the peripapillary retinal nerve fiber layer (RNFL) thickness in myopic, emmetropic, and hyperopic children using optical coherence tomography. Two-hundred one right eyes of subjects aged 4 to 18 years were divided into 3 groups based on their postcycloplegic spherical equivalent: myopes (<-1.0 D), emmetropes (≥-1.0 to ≤+1.0 D), and hyperopes (>+1.0 D). The RNFL was correlated with age, spherical equivalent, and axial length. The RNFL was compared between the 3 groups before and after age adjustment. The RNFL was thickest in the hyperopic group (107.2 ± 10.13 μm, n = 73), followed by the emmetropic group (102.5 ± 9.2 μm, n = 61), and then the myopic group (95.7 ± 10.3, n = 67) (all P < 0.0001). The myopic group (9.6 ± 3.9 years) was significantly older than the emmetropic (6.9 ± 2.7 years) and hyperopic (6.5 ± 1.9 years) groups (both P < 0.0001). When adjusted for age, myopes had a thinner RNFL than the other 2 groups (all P < 0.0001), but there was no RNFL thickness difference between the emmetropic and hyperopic groups (P > 0.05). A thinner RNFL was associated with an older age (r = -0.4, P < 0.0001), a more myopic spherical equivalent (r = 0.5, P < 0.0001), and a longer axial length (r = -0.4, P < 0.0001) on Pearson correlation analysis. The apparently thicker RNFL in hyperopic and emmetropic children was attributed to their younger age as compared with their myopic counterparts. When adjusted for age, only myopia was associated with a thinner RNFL, with emmetropic and hyperopic children having equal RNFL thicknesses. Advancing age, a more myopic spherical equivalent, and a longer axial length were associated with a thinner RNFL in children.
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http://dx.doi.org/10.1097/MD.0000000000000699DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4554015PMC
March 2015

The association between macular thickness and peripapillary retinal nerve fiber layer thickness in Chinese children.

Medicine (Baltimore) 2015 Feb;94(8):e567

From the Department of Ophthalmology (JWYL, GSKY, TTYW), Caritas Medical Centre; and Department of Ophthalmology (JWYL, JMSL), University of Hong Kong, Hong Kong Special Administrative Region, China.

To investigate the association between macular thickness and peripapillary retinal nerve fiber layer (RNFL) thickness in Chinese children. This cross-sectional study recruited consecutive cases of healthy pediatric subjects aged 4 to 18 from Caritas Medical Centre in Hong Kong Special Administrative Region, China, from 2013 to 2014. Subjects with only eye, ocular tumors, congenital glaucoma, congenital cataract, congenital nystagmus, microphthalmos, optic nerve or retinal disease, active ocular infections, corneal scars, and severe visual impairment of any cause were excluded. Peripapillary RNFL thickness and macular thickness at 1-mm-diameter fovea center (C1), 3-mm-diameter temporal quadrant (T3), and 3-mm-diameter nasal quadrant (N3) were measured with optical coherence tomography. Best-corrected visual acuity, axial length, and cycloplegic refraction were also recorded. Spearman correlation was used to analyze the association between T3, C1, and N3 with each of the following: average and quadrant RNFL thickness, axial length, and spherical equivalent. In 179 subjects, the mean age was 7.9 ± 3.6 years. There were 90 male and 89 female subjects, all of Chinese ethnicity. The mean spherical equivalent was -0.1 ± 3.1 D and mean axial length was 22.9 ± 1.4 mm. There were significant and positive correlations of the average (T3: r = 0.20, P = 0.04; N3: r = 0.2, P = 0.005), superior (T3: r = 0.20, P = 0.03; N3: r = 0.2, P = 0.03), and inferior (T3: r = 0.20, P = 0.02; N3: r = 0.2, P = 0.01) peripapillary RNFL thicknesses with the T3 and N3 macular thicknesses but not C1. The nasal peripapillary RNFL thickness was also positively correlated with T3 (r = 0.20, P = 0.01). There were no significant associations between the macular thickness (T3, C1, N3) with neither the spherical equivalent (P > 0.2) nor the axial length (P > 0.3). The macular thickness was positive correlated with the peripapillary RNFL thickness in a population of healthy Chinese children.
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http://dx.doi.org/10.1097/MD.0000000000000567DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4554147PMC
February 2015

Cross-sectional study of the retinal nerve fiber layer thickness at 7 years after an acute episode of unilateral primary acute angle closure.

Medicine (Baltimore) 2015 Jan;94(2):e391

From the Department of Ophthalmology (JWYL, TTYW, GSKY, DWFY), The Department of Ophthalmology, Caritas Medical Centre (JW); Department of Applied Mathematics (SY), The Hong Kong Polytechnic University; Department of Ophthalmology and Visual Sciences (RLMW), Hong Kong Eye Hospital; and Department of Ophthalmology (IYHW), The University of Hong Kong, Hong Kong SAR, People's Republic of China.

The purpose of this article is to investigate the long-term retinal nerve fiber layer (RNFL) status and determinants of RNFL thinning after an episode of unilateral primary acute angle closure (AAC). This cross-sectional study analyzed the medical records of consecutive patients with a single episode of unilateral AAC from 1999 to 2009 in Hong Kong. The peripapillary RNFL thickness was correlated with age, gender, presenting intraocular pressure (IOP), time to laser iridotomy, time to cataract extraction, follow-up duration, as well as the last IOP, vertical cup-to-disc ratio (CDR), and vision. The fellow uninvolved eye was used as a proxy comparison of RNFL loss in the attack eye. In 40 eligible patients, the mean age was 68.3 ± 8.7 years with a male-to-female ratio of 1:7. The mean presenting IOP was 49.2 ± 14.0 mm Hg and the time from presentation to laser iridotomy was 6.7 ± 6.9 days. Forty percent of subjects received a cataract extraction at 3.2 ± 2.9 years after the attack. The last IOP, CDR, and LogMAR vision were 16.0 ± 3.8 mm Hg, 0.6 ± 0.2, and 0.6 ± 0.6 LogMAR units, respectively, at 7.9 ± 2.4 years. The RNFL thickness in the attack eye (69.2 ± 19.1 μm) was 25.2 ± 17.9% thinner than the fellow eye (93.0 ± 17.8 μm) at 7.5 ± 2.9 years post-AAC. Using univariate analysis, the last vertical CDR (odds ratio [OR] = 17.2, P = 0.049) and LogMAR visual acuity (VA) (OR = 6.6, P = 0.03) were the only significant predictors for RNFL thinning whereas none of the other covariates showed significant associations (P > 0.1). At 7.5 years following unilateral AAC, the RNFL thickness was 25% thinner than the fellow eye. CDR enlargement and poor VA were the only significant predictors for RNFL loss.
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http://dx.doi.org/10.1097/MD.0000000000000391DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4602553PMC
January 2015

The anterior chamber depth and retinal nerve fiber layer thickness in children.

ScientificWorldJournal 2014 9;2014:538283. Epub 2014 Nov 9.

Department of Ophthalmology, Caritas Medical Centre, 111 Wing Hong Street, Kowloon, Hong Kong.

Purpose: To investigate the correlation of anterior chamber depth (ACD) with the peripapillary retinal nerve fiber layer (RNFL) thickness, age, axial length (AL), and spherical equivalent in children.

Subjects: Consecutive subjects aged 4 to 18 were recruited. Visually disabling eye conditions were excluded. Only the right eye was included for analysis. The ACD was correlated with RNFL thickness, age, spherical equivalent, and AL for all subjects. Subjects were then divided into 3 groups based on their postcycloplegic spherical equivalent: myopes (<-1.0 D), emmetropes (≥-1.0 to ≤+1.0 D), and hyperopes (>+1.0 D). The ACD was compared among the 3 groups before and after age adjustment.

Results: In 200 subjects (mean age 7.6 ± 3.3 years), a deeper ACD was correlated with thinner global RNFL (r = -0.2, r(2) = 0.06, P = 0.0007), older age (r = 0.4, r(2) = 0.1, P < 0.0001), myopic spherical equivalent (r = -0.3, r(2) = 0.09, P < 0.0001), and longer AL (r = 0.5, r(2) = 0.2, P < 0.0001). The ACD was deepest in myopes (3.5 ± 0.4 mm, n = 67), followed by emmetropes (3.4 ± 0.3, n = 60) and then hyperopes (3.3 ± 0.2, n = 73) (all P < 0.0001). After age adjustment, myopes had a deeper ACD than the other 2 groups (all P < 0.0001).

Conclusions: In children, a deeper ACD was associated with thinner RNFL thickness, older age, more myopic spherical equivalent, and longer AL. Myopes had a deeper ACD than emmetropes and hyperopes.
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http://dx.doi.org/10.1155/2014/538283DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4241318PMC
November 2015

Neuroprotective effects of lutein in a rat model of retinal detachment.

Graefes Arch Clin Exp Ophthalmol 2013 Jan 18;251(1):41-51. Epub 2012 Aug 18.

Eye Institute, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China.

Background: Retinal detachment (RD) is a leading cause of blindness, and although final surgical re-attachment rate has greatly improved, visual outcome in many macula-off detachments is disappointing, mainly because of photoreceptor cell death. We previously showed that lutein is anti-apoptotic in rodent models of ischemia/reperfusion injury. The objective of this study is to investigate lutein as a possible pharmacological adjunct to surgery.

Methods: Subretinal injections of 1.4 % sodium hyaluronate were used to induce RD in Sprague-Dawley rats until their retinae were approximately 70 % detached. Daily injections of corn oil (control group) or 0.5 mg/kg lutein in corn oil (treatment group) were given intraperitoneally starting 4 h after RD induction. Animals were euthanized 3 days and 30 days after RD and their retinae were analyzed for photoreceptor apoptosis and cell survival at the outer nuclear layer (ONL) using TUNEL staining and cell counting on retinal sections. Glial fibrillary acidic protein (GFAP) and rhodopsin (RHO) expression were evaluated with immunohistochemistry. Western blotting was done with antibodies against cleaved caspase-3, cleaved caspase-8 and cleaved caspase-9 to delineate lutein's mechanism of action in the apoptotic cascade. To seek a possible therapeutic time window, the same set of experiments was repeated with treatment commencing 36 h after RD.

Results: When lutein was given 4 h after RD, there were significantly fewer TUNEL-positive cells in ONL 3 days after RD when compared with the vehicle group. Cell counting showed that there were significantly more nuclei in ONL in lutein-treated retinae by day 30. Treatment groups also showed significantly reduced GFAP immunoreactivity and preserved RHO expression. At day 3 after RD, Western blotting showed reduced expression of cleaved caspase-3 and cleaved caspase-8 in the treatment group. No difference was found for cleaved caspase-9. When lutein was given 36 h after RD similar results were observed.

Conclusions: Our results suggest that lutein is a potent neuroprotective agent that can salvage photoreceptors in rats with RD, with a therapeutic window of at least 36 h. The use of lutein in patients with RD may serve as an adjunct to surgery to improve visual outcomes.
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http://dx.doi.org/10.1007/s00417-012-2128-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3536954PMC
January 2013

Apoptosis and other cell death mechanisms after retinal detachment: implications for photoreceptor rescue.

Ophthalmologica 2011 22;226 Suppl 1:10-7. Epub 2011 Jul 22.

Eye Institute, Li Ka Shing Faculty of Medicine, University of Hong Kong, Hong Kong, SAR, China.

Retinal detachment (RD) is one of the most common causes of blindness. This separation of the neurosensory retina from its underlying retinal pigment epithelium results in photoreceptor loss, which is the basis of permanent visual impairment. This review explores the various cell death mechanisms in photoreceptor death associated with RD. One of the major mechanisms is apoptosis, mediated by the intrinsic pathway, the Fas signalling pathway and/or the caspase-independent pathway. Other pathways of mechanisms include endoplasmic reticulum stress-mediated cell death, programmed necrosis and cytokine-related pathways. Understanding the mechanism of RD-associated photoreceptor death is likely to help us improve the current therapies or devise new strategies for this sight-threatening condition.
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http://dx.doi.org/10.1159/000328206DOI Listing
September 2011
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