Publications by authors named "Wai Kitt Chee"

4 Publications

  • Page 1 of 1

Predictors of persistent disease activity following anti-VEGF loading dose for nAMD patients in Singapore: the DIALS study.

BMC Ophthalmol 2020 Aug 6;20(1):324. Epub 2020 Aug 6.

Novartis (Singapore) Private Limited, Singapore, Singapore.

Background: To determine the frequency of persistent disease activity following 3 loading doses of anti- vascular endothelial growth factor (VEGF) agents, and the anatomic and demographic predictors of early persistent disease activity among patients with neovascular age-related macular degeneration (nAMD).

Methods: In a retrospective real-world cohort study, 281 consecutive patients with nAMD were reviewed at baseline and after 3 anti-VEGF injections for pre-defined indicators of disease activity. Optical coherence tomography (OCT) features such as subretinal fluid, intraretinal cysts and intraretinal fluid were assessed by reading-center certified graders. Multiple logistic regression was performed on demographic and anatomic factors.

Results: At month 3, 66.1% of patients had persistent disease activity. The best-corrected visual acuity (BCVA) improvement was 0.16 LogMAR for those with no disease activity compared to 0 for patients with persistent activity (p < 0.001). The significant risk factors for persistent activity at 3 months were male gender (odds ratio [OR] 0.54, 95% confidence interval [CI] 0.32-0.93, p = 0.025), intraretinal cysts at baseline (OR 2.95, 95% CI 1.67-5.20, p < 0.001) and subretinal fluid at baseline (OR 3.17, 95% CI 1.62-6.18, p = 0.002). At 3 months, 58% of patients had features of activity on OCT. Patients with intraretinal cysts and intraretinal fluid at baseline had worse BCVA at month 3 compared to patients without these OCT features (0.69 vs. 0.43, p < 0.001, and 0.62 vs. 0.43, p < 0.001, respectively).

Conclusions: In a real-world study, 66.1% of nAMD patients have persistent disease activity after the initial loading dose, with poorer BCVA compared to those without. Baseline OCT features (intraretinal cysts and subretinal fluid) are useful predictors of persistent disease activity at month 3.
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http://dx.doi.org/10.1186/s12886-020-01582-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7409440PMC
August 2020

Comparing efficacy of reduced-fluence and standard-fluence photodynamic therapy in the treatment of polypoidal choroidal vasculopathy.

BMC Ophthalmol 2020 Apr 15;20(1):150. Epub 2020 Apr 15.

National Healthcare Group Eye Institute, Tan Tock Seng Hospital, 11 Jalan Tan Tock Seng, Singapore, 308433, Singapore.

Background: The EVEREST II study reported superior polyp closure rates and visual outcomes using combination standard photodynamic therapy (PDT) with intravitreal ranibizumab in the treatment of polypoidal choroidal vasculopathy (PCV). The optimal PDT protocol remains controversial and it is postulated that less intensive PDT strategies may reduce complications. We aimed to compare the efficacy of reduced and standard-fluence PDT.

Methods: Case-control review of 38 consecutive PDT-naïve macular PCV patients who underwent verteporfin PDT using one of two PDT regimens at a tertiary referral centre in an Asian population. Comparison of outcomes between standard-fluence PDT (light dose, 50 J/cm2; dose rate, 600 mW/cm2; wavelength, 689 nm PDT applied to the treatment eye for 83 s) and reduced-fluence PDT (light dose, 25 J/cm2; dose rate, 600 mW/cm2; wavelength, 689 nm PDT applied to the treatment eye for 42 s). Primary outcome measure was best corrected LogMAR visual acuity (VA). Secondary outcome measures included OCT measurements such as central retinal thickness (CRT), height of subfoveal sub-retinal fluid (SRF), central choroid thickness (CCT), mean number of PDT treatments needed, mean number of anti-VEGF injections needed, polyp closure and recurrence rates.

Results: Of these 38 eyes of 38 patients, an equal number of eyes (19 in each arm) were treated with standard-fluence and reduced-fluence PDT. Mean letter gain at 12 months for the standard-fluence group was 6.0 compared to 4.3 letters for the reduced-fluence group (p = 0.61). Similar results were observed at all time points. There was no statistically significant difference between the retinal and choroidal anatomical OCT outcomes, rates of polyp closure and recurrences between the two PDT regimens.

Conclusions: Reduced-fluence PDT was comparable to standard-fluence PDT in the treatment of PCV in terms of visual gains, clinical and anatomical OCT outcomes.
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http://dx.doi.org/10.1186/s12886-020-01419-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7161176PMC
April 2020

Association of plasma osteopontin with diabetic retinopathy in Asians with type 2 diabetes.

Mol Vis 2018 15;24:165-173. Epub 2018 Feb 15.

Department of ophthalmology and Visual Sciences, Khoo Teck Puat Hospital, Singapore.

Purpose: Osteopontin (OPN) is a proinflammatory cytokine with diverse functions. Increased levels of OPN in vitreous fluid have been reported in patients with diabetic retinopathy (DR); however, studies on circulating OPN levels in DR are limited. We aim to examine the association of plasma OPN levels with the presence and severity of DR in a multiethnic cohort with type 2 diabetes mellitus (type 2 diabetes) in Singapore.

Methods: Plasma levels of OPN were measured using enzyme-linked immunosorbent assay. Digital color fundus photographs were assessed for DR. DR severity was categorized into non-proliferative DR (NPDR) and proliferative DR (PDR). Gradable fundus photographs and OPN measurements for 443 patients were used for analysis. A logistic regression model was used to evaluate the association of OPN with DR.

Results: DR was diagnosed in 174 (39.3%) patients, including 132 (75.9%) with NPDR and 42 (24.1%) with PDR. The median of OPN was higher in the patients with DR (64.7 [49.7-89.5] ng/ml) than in the patients without DR (51.7 [38.9-66.9] ng/ml; p<0.001). After adjustment for clinical and biochemical factors, a 1-unit increase in nature logarithm (ln)-transformed OPN was associated with the presence of DR (2.770 [1.599-3.800], p<0.001). The area under the curve (AUC) increased statistically significantly after the addition of OPN (0.805[0.763-0.846] versus 0.825 [0.785-0.865], p=0.011). In the severity analyses, the median of OPN was statistically significantly higher in the patients with PDR (76.8 [55.0-103.6] ng/ml) than in the patients with NPDR (61.7 [47.7-87.3] ng/ml; p=0.017). After adjustment, the 1-unit increase in lnOPN remained associated with NPDR (2.673 [1.519-4.704], p=0.001) and PDR (3.389 [1.254-9.226], p=0.017), respectively (p-trend=0.001).

Conclusions: Plasma OPN levels were associated with the presence and severity of DR in patients with type 2 diabetes, suggesting OPN may be useful as a potential biomarker for DR.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5815337PMC
November 2018

The Effect of a Diving Mask on Intraocular Pressure in a Healthy Population.

Case Rep Ophthalmol 2016 May-Aug;7(2):328-32. Epub 2016 Jun 13.

Ophthalmology and Visual Sciences Department, Khoo Teck Puat Hospital, Singapore, Singapore.

Purpose: Swimming goggles increase the intraocular pressure (IOP) via the periorbital frame pressure and suction effect. In comparison, diving masks have a larger frame rim and incorporate the nose. The exact effect(s) of diving masks on IOP is unknown. This study evaluates the influence of diving masks on IOP in normal, healthy subjects.

Methods: Tonometry was performed in both eyes of all subjects with an AVIA(®)Tono-Pen by a single investigator. Measurements were taken at baseline without the diving mask and with the subjects wearing a small-volume, double-window diving mask, but with the mask lenses removed. Two IOP readings in each eye were measured, and an additional reading was measured if the difference between the initial 2 was ≥2 mm Hg. Central corneal thickness (CCT) was also measured in each eye, using a contact pachymeter (OcuScan(®)Alcon).

Results: Forty eyes of 20 healthy volunteers (age 29.7 ± 9.3 years; range 21-52) were included. The mean CCT was 544.4 ± 43.5 µm. The mean IOP before the diving mask was worn had been 17.23 ± 2.18 mm Hg (n = 40). The IOP decreased by 0.43 mm Hg (p $1003c; 0.05) to 16.80 ± 2.57 mm Hg after the diving mask had been put on. There was no correlation between IOP change and age (r = 0.143, p = 0.337), gender (r = -0.174, p = 0.283) or CCT (r = -0.123, p = 0.445).

Conclusion: There was no increase in IOP after the diving mask had been worn. A small but statistically significant decrease in IOP was observed. This study demonstrates that unlike swimming goggles, the strap tension and frame pressure on the periorbital tissue from a diving mask does not increase IOP. Diving masks may be a suitable alternative to swimming goggles for patients with advanced glaucoma or glaucoma filtration surgery.
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http://dx.doi.org/10.1159/000446423DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4943308PMC
July 2016