Vesta C.K. Chan

Choroidal thickness measurement in myopic eyes by enhanced depth optical coherence tomography.

PURPOSE To measure choroidal thickness (CT) in myopic eyes using enhanced depth imaging (EDI). DESIGN A cross-sectional study. PARTICIPANTS Fifty-six consecutive patients with spherical equivalent refractive error of at least 6 diopters (D) were evaluated. METHODS Enhanced depth imaging optical coherence tomography (OCT) images were obtained by positioning the spectral-domain OCT device close enough to the eye to acquire an enhanced signal of the choroidal layer. Choroidal depth was measured as the distance between the outer reflective retinal pigment epithelium (RPE) layer and the inner sclera border. Measurements were made in a horizontal fashion across the fovea at 500-μm intervals of the sections. The CT was measured at the subfoveal region in a horizontal fashion, 3 mm temporal to fovea and 3 mm nasal to fovea. MAIN OUTCOME MEASURES Correlations among CT with age, refractive error in diopters, and visual acuity in logarithm of the minimum angle of resolution (logMAR) were analyzed with linear mixed models. RESULTS The mean age of the 56 patients was 50.4 years (± 2.03 years standard deviation; interquartile range [IQR], 42-62 years), and the mean refractive error was -8.7 D (IQR, -6.1 to -11 D). The mean subfoveal CT was 118 μm (± 68 μm) and correlated negatively with age (P = 0.032) and refractive error (P = 0.011). Regression analysis suggested that subfoveal CT decreased by 11.9 μm for each decade of life and by 6.205 μm for each diopter of myopia. The subfoveal CT was inversely correlated with the logMAR visual acuity (P = 0.008), and visual acuity improved by 0.02 (logMAR) in a 10-μm increase in CT. CONCLUSIONS Choroidal thickness decreases with age and severity of myopia. Visual acuity decreases in line with decreasing subfoveal CT. A reduction in CT is related to aging and the severity of myopia, whereas visual acuity depends on subfoveal CT. Our study supports the theory that choroidal abnormality may play a key role in the pathogenesis of myopic degeneration. FINANCIAL DISCLOSURE(S) The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Gender specific association of a complement component 3 polymorphism with polypoidal choroidal vasculopathy

Neovascular age-related macular degeneration (AMD) and polypoidal choroidal vasculopathy (PCV) are leading causes of irreversible blindness in developed countries. In this study, we investigated the associations of haplotype-tagging single nucleotide polymorphisms (SNPs) in the complement component 3 (C3) gene with both neovascular AMD and PCV, and potential epistatic effects on C3. Eight tagging SNPs in C3 were genotyped in 708 unrelated study subjects: 200 neovascular AMD patients, 233 PCV patients and 275 controls. Among the eight C3 SNPs, rs17030 was associated with PCV after adjusted for gender and SNP-gender interaction (P = 0.008, OR = 2.94; 95% CI: 1.32-6.52). Moreover, an interaction between rs17030 and gender was identified in PCV (P = 0.02). After stratification by gender, the rs17030 G allele was found to confer an increased risk for PCV in male (P = 0.010, OR = 1.56) but not in female. The haplotype AG defined by the major alleles of rs17030 and rs344555 was also associated with PCV in male (P = 0.010, OR = 0.64). In contrast to PCV, none of the eight SNPs was significantly associated with neovascular AMD. This study shows an association of C3 rs17030 with PCV in male, indicating that C3 may have an epistatic effect with gender in the pathogenesis of PCV.

Treatment of polypoidal choroidal vasculopathy by photodynamic therapy, aflibercept and dexamethasone triple therapy

Polypoidal choroidal vasculopathy is a relatively common type of degenerative macular disease among the Chinese population. This study aims to describe the therapeutic responses to combination therapy with photodynamic therapy, intravitreal aflibercept and intravitreal dexamethasone in patients with polypoidal choroidal vasculopathy. A prospective series of 17 eyes of 13 patients suffering from treatment-naïve polypoidal choroidal vasculoapathy were recruited. All cases received triple therapy with photodynamic therapy, intravitreal aflibercept and intravitreal dexamethasone and one year outcomes were reported. The baseline visual acuity was 0.65logMAR +/− 0.38 (Snellen 20/80 to 20/100). The visual acuity at 1 week, 3 months, 6 months and one year after treatment were significantly improved to 0.522logMAR+/− 0.365 (P < 0.04) (Snellen 20/70), 0.363logMAR+/−0.382 (Snellen 20/50;P < 0.001), 0.377logMAR +/− 0.440 (Snellen 20/50;p = 0.005), and 0.35logMAR +/− 0.407 (Snellen 20/40;P < 0.001), respectively. The baseline central foveal thickness (CFT) on optical coherence tomography (OCT) was 394.7 +/− 70.6 μm. CFT at 6 months and 1 year after treatment were significantly reduced to 259 +/− 54 μm (p = 0.004) and 271 +/− 49.7 μm(p = 0.016), respectively. Triple therapy with photodynamic therapy, intravitreal aflibercept and intravitreal dexamethasone is an effective treatment for polypoidal choroidal vasculopathy. The majority of cases responded well with significant responses observed as early as 1 week after initiation of therapy.

Identification of ANGPT2 as a New Gene for Neovascular Age-Related Macular Degeneration and Polypoidal Choroidal Vasculopathy in the Chinese and Japanese Populations

Purpose We determine the angiopoietin 2 (ANGPT2) gene as a new susceptibility gene for neovascular age-related macular degeneration (nAMD) and polypoidal choroidal vasculopathy (PCV). Methods A total of 34 haplotype-tagging single-nucleotide polymorphisms (SNPs) were first genotyped in an exploratory Hong Kong Chinese cohort. Suggestive SNPs were replicated in a Shantou Chinese cohort and an Osaka Japanese cohort, with a total of 2343 subjects. The SNP rs800292 in the complement factor H (CFH) gene was genotyped in all the subjects. Genetic association and gene-gene interaction were analyzed. Results In the Hong Kong cohort, four SNPs in ANGPT2 (rs13255574, rs4455855, rs13269021, and rs11775442) were nominally associated with nAMD and PCV. The four ANGPT2 SNPs showed the same trends of association in the Shantou and Osaka cohorts. Combining the data from the 3 study cohorts revealed that SNPs rs4455855 and rs13269021 achieved study-wise significance (P < 0.0016), conferring an approximately 1.3-fold of increased risk for nAMD and PCV. Interaction analysis revealed the CFH SNP rs800292 has a highly significant interaction with the ANGPT2 SNP rs13269021 in nAMD and PCV in the combined analysis. Subsequent stratification analysis confirmed the interaction. Conclusions This study reveals ANGPT2 as a new susceptibility gene for nAMD and PCV, and it may affect disease susceptibility in association with CFH. Thus, this report provides new insights into the genetic architecture of nAMD and PCV.

SUCCESSFUL TREATMENT OF REFRACTORY PROLIFERATIVE RETINOPATHY OF INCONTINENTIA PIGMENTI BY INTRAVITREAL RANIBIZUMAB AS ADJUNCT THERAPY IN A 4-YEAR-OLD CHILD.

Purpose: To describe a case of incontinentia pigmenti with proliferative retinopathy successfully treated by combination of repeated retinal laser photocoagulation and intravitreal ranibizumab injection. Methods: Single interventional case report of a 4-year-old girl, known case of incontientia pigmenti, first screened at the age of two, presented with proliferative retinopathy. Sole treatment by panretinal laser photocoagulation failed to control the progression of retinal neovascularization. Intravitreal ranibizumab injections were used as an adjunct therapy. Results: The proliferative retinopathy was brought under control and halted till this date with repeated intravitreal ranibizumab and panretinal photocoagulation. No systemic side effect was noted. Conclusion: Intravitreal ranibizumab can be considered as an adjunct therapy in proliferative retinopathy secondary to incontinentia pigmenti when monotherapy with panretinal photocoagulation fails. Intravitreal ranibizumab may quickly inhibit the intraocular vascular endothelial growth factor and may prevent devastating complications like tractional retinal detachment. Extra caution has to be taken in adopting different dosages and injection regimes especially in pediatric cases.

Association of ABCG1 With Neovascular Age-Related Macular Degeneration and Polypoidal Choroidal Vasculopathy in Chinese and Japanese.

Purpose We investigated the association of the ATP-binding cassette, subfamily G, member 1 (ABCG1) gene with polypoidal choroidal vasculopathy (PCV) and neovascular age-related macular degeneration (nAMD) in independent Chinese and Japanese cohorts. Methods A total of 12 haplotype-tagging single-nucleotide polymorphisms (SNPs) and the SNP rs57137919 in the ABCG1 gene were first analyzed in a Hong Kong Chinese cohort of 235 nAMD, 236 PCV, and 365 controls, using TaqMan genotyping assays. Two SNPs (rs57137919 and rs225396) that showed a disease-association were genotyped in a Shantou Chinese cohort of 189 nAMD, 187 PCV, and 670 controls, and an Osaka Japanese cohort of 192 nAMD, 204 PCV, and 157 controls, totaling 2435 subjects. Association analysis was performed in individual cohorts, followed by a pooled analysis of the data from all three cohorts. Results In the Hong Kong cohort, SNP rs57137919 was associated with PCV (odds ratio [OR] = 1.35). A tagging SNP rs225396 was associated with nAMD (OR = 1.28) and PCV (OR = 1.32). In the Osaka cohort, SNP rs225396 was associated with nAMD (OR = 1.42) and PCV (OR = 1.74). In the pooled analysis involving the 3 study cohorts, rs225396 showed an enhanced association with nAMD (P = 0.01, OR = 1.21, I2 = 14%) and PCV (P = 0.0001, OR = 1.35, I2 = 46%). Conclusions In this study, we have newly identified a haplotype-tagging SNP, rs225396, in ABCG1 to be associated with PCV and nAMD in Chinese and Japanese cohorts. This provides new evidence to support ABCG1 as a susceptibility gene for PCV and nAMD. Further replication in other populations should be warranted.

The Incidence of Postoperative Endophthalmitis Before and After a Revised Preoperative Surgical Site Preparation Protocol.

PurposeTo compare the incidence of postoperative endophthalmitis before and after the implementation of a preoperative surgical site preparation protocol for cataract surgery. DesignRetrospective cohort study. MethodsRecords of patients with postoperative endophthalmitis between January 2006 and August 2013 were reviewed. A revised protocol implemented after January 2009 included the addition of preoperative 0.3% topical tobramycin, 10% povidone-iodine for cleansing, and using a disposable sterile drape. The incidence, microbiological profile, and outcomes of these cases were analyzed. ResultsThe incidence of preprotocol endophthalmitis was significantly higher than in the postprotocol period (P = 0.018). More patients in the preprotocol group grew Pseudomonas aeruginosa and Streptococcus pneumoniae as compared with those in the postprotocol group (P = 0.014). A smaller number of patients attained a poor visual outcome after the implementation of the revised protocol (P = 0.035). ConclusionsIn our study, the addition of antibiotic eye drops before cataract surgery and perioperative cleansing with 10% povidone-iodine were effective means to reduce the incidence of postoperative endophthalmitis.

Prospective Randomized Comparative Study of the Effect of Pupil Dilation or Miosis in Intraocular Lens Pupillary Capture After Combined Phacoemulsification and Vitrectomy With Intraocular Tamponade.

PurposeThe objective of the study was to compare the safety and efficacy of postoperative pharmacological pupil dilation, miosis, and alternate-day pupil dilation and miosis after combined phacoemulsification (phaco), intraocular lens (IOL) implantation, and pars plana vitrectomy (PPV) with intraocular tamponade. DesignThis was a prospective, randomized controlled clinical trial. MethodsPatients who were indicated for phaco with IOL implantation, PPV, and intraocular tamponade were randomly assigned into 3 different groups: (1) pupil dilation using 4% homatropine (dilation group), (2) pupil miosis using 1% pilocarpine (miosis group), and (3) alternate-day pupil miosis and dilation starting with 1% pilocarpine on the first day postoperatively and switched to 4% homatropine thereafter on alternate days (alternate-day group). The main outcome measured was the rate of IOL capture postoperatively. The secondary measurable outcomes were the complication rates, visual acuity, and ease of fundal examination with binocular indirect ophthalmoscopy. ResultsTwenty-two, 21, and 20 eyes were allocated to the dilation, miosis, and alternate-day groups, respectively. Intraocular lens capture was found in 7 (11.1%) of 63 eyes. Intraocular lens was captured in 6 (27.3%) of 22 eyes in the dilation, 1 (4.5%) of 21 eyes in the miosis, and none in the alternate-day groups (P = 0.0133). The difference of the visual acuity among the 3 groups was not statistically significant (P = 0.650). Anterior chamber reaction of more than +1 cell in the first week was found in 6 (27.3%) of 22, 13 (61.9%) of 21, and 10 (50%) of 20 eyes in the dilation, miosis, and alternate-day groups, respectively (P = 0.074). Although more eyes were found with posterior synechia in the miosis group, the difference was not statistically significant (P = 0.478). The number of eyes that had suboptimal binocular indirect ophthalmoscopy view was 3 (13.6%) of 22, 12 (57.1%) of 21, and 6 (30%) of 20 in the dilation, miosis, and alternate-day groups, respectively (P = 0.01). ConclusionsPupil dilation after combined phaco with IOL implantation, PPV, and intraocular tamponade could lead to a higher chance of IOL capture. Pupil miosis may lead to more anterior chamber inflammation. The regimen of alternate pupil dilation and miosis may cause less chance of IOL capture.

Klebsiella endophthalmitis as the herald of occult colorectal cancer

A 67-year-old Chinese man presented with acute loss of vision and pain in the left eye with hypopyon in the anterior chamber. The patient was afebrile with no systemic symptoms at presentation. Diagnosis of endogenous endophthalmitis was made with vitreous tap yielding Klebsiella pneumoniae. Pars plana vitrectomy was performed twice to clear the infection. Thorough investigations showed no septic foci. Whole body positron emission tomography CT revealed a rectal tumour and biopsy showed adenocarcinoma. He was treated with neoadjuvant chemoirradiation followed by surgery to resect the tumour. Vision in the left eye was hand movement at 12 months postoperatively. This case illustrates Klebsiella endogenous endophthalmitis might be a herald of occult colorectal cancer. Bacteria might gain access into bloodstream via mucosal defect in the tumour.