Effects of firsthand tobacco smoking on retinal vessel caliber: a systematic review and meta-analysis

PURPOSE

To review the effects of firsthand tobacco smoking on central retinal arteriolar equivalent (CRAE) and central retinal venular equivalent (CRVE) of firsthand tobacco smokers.

METHODS

We performed a search on EMBASE and PubMed for studies up to 15th July 2022. Two independent reviewers selected studies with baseline data of CRAE and CRVE of current smokers, nonsmokers, and former smokers. Initial search identified 893 studies, of which 10 were included in the meta-analysis. Two independent reviewers extracted data from the included studies. The quality of studies was assessed by the Newcastle-Ottawa Scale.

RESULTS

In this meta-analysis, 7431 nonsmokers, 2448 current smokers and 5786 former smokers, as well as 7404 nonsmokers, 2430 current smokers and 5763 former smokers were included in CRAE and CRVE analysis respectively. Nonsmokers had narrower CRVE (Weighted mean difference [WMD], -12.15; 95% CI, -17.33 - -6.96) and CRAE (WMD, -4.77; 95% CI, -7.96 - -1.57) than current smokers, and narrower CRVE (WMD, -3.08; 95% CI, -6.06 - -0.11) than former smokers. Current smokers had wider CRVE (WMD, 10.42; 95% CI, 7.80 - 13.04) and CRAE (WMD, 7.05; 95% CI, 6.65 - 7.46) than former smokers. Subgroup analysis and sensitivity analysis were performed.

CONCLUSION

Firsthand tobacco smoking resulted in wider CRAE and CRVE in current and former smokers, particularly in CRVE, and such changes may not be reversible after smoking cessation. Therefore, retinal vessel caliber may reflect the effects of firsthand tobacco smoking and be used to estimate the risk of cardiovascular diseases.

Five-Year Clinical Trial of the Low-Concentration Atropine for Myopia Progression (LAMP) Study: Phase 4 Report

PURPOSE

To evaluate (1) the long-term efficacy of low-concentration atropine over 5 years, (2) the proportion of children requiring re-treatment and associated factors, and (3) the efficacy of pro re nata (PRN) re-treatment using 0.05% atropine from years 3 to 5.

DESIGN

Randomized, double-masked extended trial.

PARTICIPANTS

Children 4 to 12 years of age originally from the Low-Concentration Atropine for Myopia Progression (LAMP) study.

METHODS

Children 4 to 12 years of age originally from the LAMP study were followed up for 5 years. During the third year, children in each group originally receiving 0.05%, 0.025%, and 0.01% atropine were randomized to continued treatment and treatment cessation. During years 4 and 5, all continued treatment subgroups were switched to 0.05% atropine for continued treatment, whereas all treatment cessation subgroups followed a PRN re-treatment protocol to resume 0.05% atropine for children with myopic progressions of 0.5 diopter (D) or more over 1 year. Generalized estimating equations were used to compare the changes in spherical equivalent (SE) progression and axial length (AL) elongation among groups.

MAIN OUTCOMES MEASURES

(1) Changes in SE and AL in different groups over 5 years, (2) the proportion of children who needed re-treatment, and (3) changes in SE and AL in the continued treatment and PRN re-treatment groups from years 3 to 5.

RESULTS

Two hundred seventy (82.8%) of 326 children (82.5%) from the third year completed 5 years of follow-up. Over 5 years, the cumulative mean SE progressions were -1.34 ± 1.40 D, -1.97 ± 1.03 D, and -2.34 ± 1.71 D for the continued treatment groups with initial 0.05%, 0.025%, and 0.01% atropine, respectively (P = 0.02). Similar trends were observed in AL elongation (P = 0.01). Among the PRN re-treatment group, 87.9% of children (94/107) needed re-treatment. The proportion of re-treatment across all studied concentrations was similar (P = 0.76). The SE progressions for continued treatment and PRN re-treatment groups from years 3 to 5 were -0.97 ± 0.82 D and -1.00 ± 0.74 D (P = 0.55) and the AL elongations were 0.51 ± 0.34 mm and 0.49 ± 0.32 mm (P = 0.84), respectively.

CONCLUSIONS

Over 5 years, the continued 0.05% atropine treatment demonstrated good efficacy for myopia control. Most children needed to restart treatment after atropine cessation at year 3. Restarted treatment with 0.05% atropine achieved similar efficacy as continued treatment. Children should be considered for re-treatment if myopia progresses after treatment cessation.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Light exposure therapy for myopia control: a systematic review and Bayesian network meta-analysis

AIMS

To compare and rank the myopia control effects of different light wavelengths in children using a systematic review and Bayesian network meta-analysis (Bayesian NMA).

METHODS

The review protocol was registered with PROSPERO. We searched PubMed, EMBASE and MEDLINE for relevant clinical and animal studies published as of 2 February 2023. We included studies comparing red, violet or full-spectrum light with controls. Data extracted included descriptive statistics and study outcomes (axial length (AL) elongation and progression of spherical equivalent (SE) refraction). After quality assessment, estimates of treatment effect outcomes (mean differences (MDs) and 95% CIs) were first pooled for the animal and clinical studies in a traditional meta-analysis. To compare and rank the different light wavelengths, the Bayesian NMA was then conducted for all the included clinical studies (12 studies) and separately for only randomised controlled trials (8 studies). MDs, 95% credible intervals (CrIs) and ranks of the various light wavelengths were estimated in the Bayesian NMA.

RESULTS

When all clinical studies were included in the Bayesian NMA (12 studies), only red-light significantly slowed AL elongation, MD (95% CrI), -0.38 mm (-0.59 mm to -0.16 mm)/year and SE refraction progression, 0.72D (0.35D to 1.10D)/year compared with controls. It remained the only significant intervention when effect sizes from only RCTs (eight studies) were separately combined, (-0.28 mm (-0.40 mm to -0.15 mm)/year and 0.57D (0.22D to 0.92D)/year, for AL and SE refraction, respectively).

CONCLUSION

Myopia control efficacy varied among different wavelengths of light, with red light ranked as the most effective.

PROSPERO REGISTRATION NUMBER

Clinical studies: CRD42022368998; animal studies: CRD42022368671.

Interocular Symmetry in Retinal Nerve Fiber Layer Thickness in Children: The Hong Kong Children Eye Study

INTRODUCTION

The aim of this work is to determine the interocular differences in peripapillary retinal nerve fiber layer (p-RNFL) thickness and its associations among school children in Hong Kong.

METHODS

We conducted a population-based study including 4034 children aged 6-8 years from the Hong Kong Children Eye Study (HKCES). All participants received comprehensive ocular examinations where p-RNFL thickness was measured using spectral-domain optical coherence tomography (SD-OCT). The degree of symmetry between both eyes was analyzed and represented by intraclass correlation coefficient (ICC) values. Multivariable linear regression analysis was used to investigate the associations between ocular and systemic factors with p-RNFL thickness difference.

RESULTS

The study included 4034 children with a mean age of 7.61 ± 0.98 years. The mean global p-RNFL thickness was 106.60 ± 9.41 μm in right eyes and 105.99 ± 9.30 μm in left eyes. The ICC for global p-RNFL difference was 0.866 (95% CI 0.858-0.873, p < 0.001). The symmetry displayed the largest values in nasal inferior quadrant with the ICC value of 0.736 (95% CI 0.721-0.749); and the smallest degree of symmetry was found to be in the superior temporal quadrant with the ICC value of 0.567 (95% CI 0.546-0.588). Axial length (AL) difference was found to have more pronounced correlation to interocular symmetry in p-RNFL thickness with the coefficient of 0.514 (p < 0.001).

CONCLUSIONS

Normal variation in interocular symmetry exists in children. Our results can contribute to the establishment of a standard reference for interocular differences in OCT parameters in children. The interocular differences in AL should be considered in the interpretation of RNFL symmetry, in terms of identifying children at risk of developing glaucoma or other ocular disorders.

Iris depigmentation and cytomegalovirus in aqueous humor as predictors of uveitic activity and recurrence in chronic and recurrent anterior uveitis

PURPOSE

To examine the clinical outcomes in chronic or recurrent anterior uveitis in the presence or absence of cytomegalovirus (CMV) and investigate the predictive factors for uveitic activity and recurrence.

METHODS

Polymerase chain reaction (PCR) was performed in a prospective cohort of immunocompetent adults with recurrent or chronic anterior uveitis to detect CMV in aqueous humor. The clinical outcomes were compared between eyes with and without CMV DNA. Logistic regression was performed to evaluate associations between iris depigmentation, CMV-PCR status, uveitic activity, and recurrence.

RESULTS

Thirty-eight eyes of 38 subjects with a mean age of 61.1 ± 11.2 years old were analyzed. Fifteen eyes were positive for CMV. More eyes with CMV developed recurrences and remained actively inflamed at 6, 12, and 24 weeks though the differences were insignificant. The presence of iris depigmentation was predictive of a greater odd of uveitic recurrences by 12 and 24 weeks (Odds ratio (OR) = 9.17 and 5.72, P = 0.007 and 0.034 respectively), whereas positive CMV-PCR predicts a greater odd of uveitic activity at postoperative 12 and 24 weeks (OR = 13.08, 34.30; P = 0.027, 0.007).

CONCLUSION

Eye with and without detectable CMV behaved similarly in their clinical course. Our findings suggested that iris depigmentation was predictive of more frequent uveitic recurrence, regardless of the PCR status, whereas the presence of CMV in aqueous humor was associated with persistent uveitic activity. Iris changes may be present during the earlier phase of the disease and precede the detection of virus from the aqueous humor at a later stage of CMV infection.

Corneal nerve changes in herpes zoster ophthalmicus: a prospective longitudinal in vivo confocal microscopy study

PURPOSE

To study the changes in corneal nerves and corneal sensitivity over a 6-month period in patients with herpes zoster ophthalmicus (HZO) compared with healthy subjects.

METHODS

This was a prospective longitudinal study on patients with newly diagnosed HZO. In vivo confocal microscopy (IVCM) corneal nerve parameters and corneal sensitivity were measured and compared between eyes with HZO, contralateral eyes and controls at baseline, 2 and 6 months.

RESULTS

Fifteen subjects with HZO and 15 healthy age and sex matched controls were recruited. HZO eyes revealed a reduction in corneal nerve branch density (CNBD) from baseline to 2 months (9.65 ± 5.75 vs. 5.90 ± 6.87/mm2, p = 0.018), and decreased corneal nerve fibre density (CNFD) at 2 months when compared with control (p = 0.025). However, these differences resolved by 6 months. HZO fellow eyes demonstrated increased corneal nerve fibre area (CNFA), corneal nerve fibre width (CNFW) and corneal nerve fractal dimension (CNFrD) at 2 months compared with baseline (p = 0.025, 0.031, 0.009). There was no change in corneal sensitivity for both HZO affected and HZO fellow eyes from baseline or over time, nor was it different from sensitivity in controls.

CONCLUSION

Corneal denervation was present at 2 months in HZO eyes, with an observed recovery by 6 months. HZO fellow eyes demonstrated increased corneal nerve parameters at 2 months, which could represent a proliferative response to nerve degeneration. IVCM is useful in monitoring corneal nerve changes, and is more sensitive in detecting nerve alterations than esthesiometry.

Increase in Bruch's membrane opening minimum rim width with age in healthy children: the Hong Kong Children Eye Study

BACKGROUND/AIMS

To identify normative values and determinants for Bruch's membrane opening (BMO) and the minimum rim width of BMO (BMO-MRW) among healthy children.

METHODS

A population-based cross-sectional study from the Hong Kong Children Eye Study, recruiting 1, 226 children aged 6-8 years. Spherical refractive error, axial length (AL), body mass index and intraocular pressure (IOP) were measured. The optic nerve head and the peripapillary retinal nerve fibre layer (p-RNFL) were imaged through spectral domain-optical coherence tomography, using 24 equally spaced radial B-scans. Global and sectoral BMO-MRW values, BMO area and fovea-to-BMO (FoBMO) angle were calculated. Multiple regression analysis was performed to define the determinants of BMO area and BMO-MRW in relation to demographic and ocular parameters.

RESULTS

The mean values for global BMO-MRW, BMO area and FoBMO angle among children were 345.76±54.08 µm, 2.34±0.49 mm2 and -5.45±4.36°, respectively. Global and sectoral values for BMO-MRW correlated with p-RNFL thickness (r=0.11-0.35, p<0.001). After adjusting for demographic and ocular parameters, global BMO-MRW increased with age (β=6.4, p<0.001) and greater global p-RNFL thickness (β=1.41, p<0.001), but decreased with larger BMO area (β=-47.46, p<0.001) and higher IOP (β=-1.73, p<0.001). Global BMO-MRW did not associate with AL, whereas both BMO area and FoBMO angle associated with AL (β=0.04, p=0.02 and β=0.31, p=0.03, respectively), but not with age.

CONCLUSION

We observed that BMO-MRW increases with age among children. Our results provide normative values and the determinants of BMO parameters among Chinese children.

Acute postoperative endophthalmitis after cataract operation: result of early vitrectomy within 24 hours of presentation

OBJECTIVES

To evaluate result of early pars plana vitrectomy (PPV) within 24 hours of presentation for acute postoperative endophthalmitis after cataract operation, and to determine factors that predict visual outcome.

METHODS

Consecutive patients who developed acute postoperative endophthalmitis within 6 weeks after cataract operation were reviewed. Patients were divided into two groups for analysis: (1) those receiving PPV within 24 hours of presentation (early PPV group), and (2) those receiving initial intravitreal antibiotics only without PPV within 24 hours of presentation (IVA group).

RESULTS

Out of 41,411 cataract operations, 22 eyes developed acute postoperative endophthalmitis. Presenting VA was hand-movement or worse in 72.7%. The most common organisms were Staphylococcus (40.9%), Streptococcus (13.6%) and Enterococcus (13.6%). 22.7% of eyes had good final VA ≥ 20/30 and 27.3% had poor final VA < 20/400. Early PPV group had significantly lower rate of requiring additional treatments to control infection (25% versus 80%, P = 0.030), higher rate of retinal detachment (25% versus 0%, P = 0.221) and similar final logMAR VA (1.08 ± 1.08 versus 0.80 ± 0.80, P = 0.489) compared to IVA. Multivariate linear regression analysis showed that worse final VA was significantly associated with Streptococcus (ß = 1.92, P = 0.007) and retinal detachment (ß = 1.72, P = 0.005) but not with early PPV (P = 0.225).

CONCLUSION

Early PPV was superior to initial intravitreal antibiotics alone as it required fewer additional treatments to control infection. Visual outcome was similar between early PPV and initial intravitreal antibiotics alone despite high number of poor presenting VA of light-perception in early PPV group. Streptococcal infection and retinal detachment were major poor prognostic factors for vision.

Association of Polymorphisms in ZFHX1B and PAX6 With Anisometropia in Chinese Children: The Hong Kong Children Eye Genetics Study

Purpose

To identify gene variants associated with anisometropia development in children.

Methods

This is a population-based, cross-sectional, and longitudinal genetic association study involving 1057 children aged 6 to 10 years with both baseline and 3-year follow-up data. Six single nucleotide polymorphisms (SNPs), ZC3H11B rs4373767, ZFHX1B rs13382811, KCNQ5 rs7744813, SNTB1 rs7839488, PAX6 rs644242, and GJD2 rs524952 were analyzed in all children. Anisometropia was defined by an interocular difference in SE of ≥1 diopter (D) (Aniso-SE) and an interocular difference in axial length (AL) of ≥0.3 mm (Aniso-AL), respectively. Genetic associations of individual SNPs and joint SNP effects were analyzed.

Results

ZFHX1B rs13382811 was associated nominally with Aniso-AL (odds ratio [OR], 1.66; P = 0.003) at baseline. At 3 years, rs13382811 was significantly associated with Aniso-AL (OR, 1.49; P = 0.001) and became nominally associated with Aniso-SE (OR, 1.40; P = 0.01). In addition, PAX6 rs644242 was significantly associated with Aniso-AL at 3 years (OR, 1.45; P = 0.002). At the 3-year follow-up, PAX6 rs644242 was associated significantly with Aniso-AL development (OR, 1.61; P = 0.0003) and nominally with Aniso-SE development (P = 0.03) in children who were not anisometropic at baseline, whereas ZFHX1B rs13382811 was associated nominally with Aniso-AL development (P = 0.02). An additive SNP analysis indicated children carrying the risk allele T of ZFHX1B rs13382811 and allele A of PAX6 rs644242 might have a 4.33- and 6.90-fold of increased risk of Aniso-SE and Aniso-AL development by 3 years, respectively.

Conclusions

This study identified two susceptible gene variants, ZFHX1B rs13382811 and PAX6 rs644242, for anisometropia development in Hong Kong Chinese children, implicating their role in imbalanced refractive change and axial elongation between both eyes.

Analysis of Secondhand Smoke Exposure and Myopia Among Children Aged 6 to 8 Years in Hong Kong

Importance

Secondhand smoke (SHS) exposure potentially threatens ocular health; however, its association with myopia is unknown.

Objective

To examine the association between SHS exposure and childhood myopia.

Design, Setting, and Participants

Cross-sectional data from the population-based Hong Kong Children Eye Study were used. Data were collected from March 5, 2015, to September 12, 2021, at The Chinese University of Hong Kong Eye Center. Participants included children aged 6 to 8 years. Secondhand smoke exposure was evaluated using a validated questionnaire. All participants underwent comprehensive ophthalmic and physical examinations.

Exposure

Secondhand smoke exposure.

Main Outcomes and Measures

Generalized estimating equations were constructed to examine the association of SHS exposure with spherical equivalent and axial length; logistic regression models, with myopia rate; and linear regression models, with myopia onset.

Results

A total of 12 630 children (mean [SD] age, 7.37 [0.88] years; 53.2% boys) were included in the analysis. Among the participants, 4092 (32.4%) had SHS exposure. After adjusting for age, sex, parental myopia, body mass index, near-work time, outdoor time, and family income, SHS exposure was associated with greater myopic refraction (β = -0.09 [95% CI, -0.14 to -0.03]) and longer axial length (β = 0.05 [95% CI, 0.02-0.08]). Children with SHS exposure were more likely to develop moderate (odds ratio [OR], 1.30 [95% CI, 1.06-1.59]) and high myopia (OR, 2.64 [95% CI, 1.48-4.69]). The association of SHS exposure with spherical equivalence and axial length was magnified in younger children. For each younger year of a child's exposure to SHS, SHS exposure was associated with a 0.07-D decrease in spherical equivalence (β = 0.07 [95% CI, 0.01-0.13]) and a 0.05-mm increase in axial length (β = -0.05 [95% CI, -0.08 to -0.01]). Exposure to SHS was associated with an earlier mean (SD) age at onset of myopia (72.8 [0.9] vs 74.6 [0.6] months; P = .01). Every increase in SHS exposure in units of 10 cigarettes per day was associated with greater myopic refraction (β = -0.07 [95% CI, -0.11 to -0.02]), axial length (β = 0.04 [95% CI, 0.01-0.06]), and likelihood of developing moderate (OR, 1.23 [95% CI, 1.05-1.44]) and high myopia (OR, 1.75 [95% CI, 1.20-2.56]), and earlier myopia onset (β = -1.30 [95% CI, -2.32 to -0.27]).

Conclusions and Relevance

The findings of this cross-sectional study suggest that SHS exposure was associated with greater myopic refraction, longer axial length, greater likelihood of developing moderate and high myopia, and earlier myopia onset. The larger the quantity of SHS exposure and the younger the child, the more advanced myopia development and progression with which SHS exposure is associated.

Prevalence and Characteristics of Peripapillary Gamma Zone in Children With Different Refractive Status: The Hong Kong Children Eye Study

Purpose

This study aimed to assess the prevalence and characteristics of the peripapillary gamma zone in myopic, emmetropic, and hyperopic eyes of Chinese children.

Methods

Overall, 1274 children aged 6 to 8 years from the Hong Kong Children Eye Study underwent ocular examinations, including measurements of cycloplegic auto-refraction and axial length (AL). The optic disc was imaged using a Spectralis optical coherence tomography (OCT) unit and a protocol involving 24 equally spaced radial B-scans. The Bruch's membrane opening (BMO) was identified in over 48 meridians in each eye. The peripapillary gamma zone was defined as the region between the BMO and the border of the optic disc, identified by the OCT.

Results

The prevalence of the peripapillary gamma zone was higher in myopic eyes (36.3%) than in emmetropic (16.1%) and hyperopic eyes (11.5%, P < 0.001). AL (per 1 mm; odds ratio [OR]) = 1.861, P < 0.001) and a more oval disc shape (OR = 3.144, P < 0.001) were associated with the presence of a peripapillary gamma zone after adjusting for demographic, systemic, and ocular variables. In the subgroup analysis, a longer AL was associated with the presence of a peripapillary gamma zone in myopic eyes (OR = 1.874, P < 0.001), but not in emmetropic (OR = 1.033, P = 0.913) or hyperopic eyes (OR = 1.044, P = 0.883). A peripapillary zone was not observed in the region nasal to the optic nerve in myopic eyes, in contrast to its presence in the same region in 1.9% of emmetropic eyes and 9.3% of hyperopic eyes; these intergroup differences were statistically significant (P < 0.001).

Conclusions

Although peripapillary gamma zones were observed in the eyes of both myopic and non-myopic children, their characteristics and distribution patterns were substantially different.

A review on drug-induced dry eye disease

Dry eye disease encompasses a broad range of etiologies and disease subtypes which have similar clinical manifestations. Medications can cause dry eye disease or symptoms of dryness as a side effect by either interfering with the lacrimal gland or meibomian gland function, or both, and by other mechanisms that affect the ocular surface homeostasis. This is important to know and recognize as eliminating the offending medication can reverse the symptoms and, in many cases, prevent further deterioration of the ocular surface inflammation. This review focuses on drugs like systemic isotretinoin and taxanes, which cause meibomian gland dysfunction; immune checkpoint inhibitors that cause lacrimal gland dysfunction; gliptins and topical antiglaucoma medications that cause cicatrizing conjunctivitis; and epidermal growth factor receptor inhibitors, fibroblast growth factor receptor inhibitors, and belantamab mafodotin, which cause mucosal epitheliopathy. Many of these medications, particularly the newer anticancer agents, have only recently been introduced for clinical use, and knowledge and awareness of their ocular side effects are still evolving. This review aims to update ophthalmologists on the drug-induced causes of dry eye disease or symptoms of dryness, which is avoidable by discontinuation of the incriminating agent or can be mitigated by reducing the dose or frequency of usage.

Differential compensatory role of internal astigmatism in school children and adults: The Hong Kong Children Eye Study

BACKGROUND

To compare the prevalence of refractive (RA), corneal (CA), and internal astigmatism (IA) in Hong Kong children and adults and evaluate the role of IA in compensating for total astigmatism and its relations to myopic traits.

METHODS

The Hong Kong Children Eye Study is a population-based cross-sectional study. Totally 3704 school children (mean age 7.5 ± 1.0 years) and 5577 adults (mean age 41.1 ± 7.5 years), who were their parents, were recruited. Cycloplegic and non-cycloplegic refractive cylinders were obtained from children and adults, respectively. Spearman correlation was applied to detect associations between astigmatism, ocular biometrics, refraction, and lens power. Astigmatism compensation factor (CF) was derived from the power vector analysis J0 and J45.

RESULTS

The prevalence of RA (≤-1.0 D), CA (≥+1.0 D) and IA (≥+1.0 D) was 21.9%, 63.9%, and 9.9% in children, and 30.9%, 39.5%, and 23.7% in adults respectively. The mean RA, CA and IA values in children and adults were -0.69 ± 0.66 D, +1.14 ± 0.61 D, +0.62 ± 0.32 D, and -0.80 ± 0.74 D, +0.97 ± 0.69 D, and +0.76 ± 0.43 D, respectively. In adults and children, IA was negatively correlated with axial length (p < 0.0001), but positively correlated with spherical values and equivalent (p < 0.0001), suggesting an association of astigmatism with myopic traits. A greater proportion of children exhibited compensation by IA than adults in J0 (86.6% vs. 66.0%, p < 0.0001) and J45 components (55.5% vs. 41.7%, p < 0.0001).

CONCLUSIONS

Chinese children in Hong Kong exhibit a higher prevalence of RA and CA than in other cities. Children displayed a greater compensation by IA than adults, suggesting an age-related attenuation of IA compensation. IA is associated with myopic traits.

Prevalence of Myopia in Children Before, During, and After COVID-19 Restrictions in Hong Kong

Importance

Childhood myopia increased during the COVID-19 pandemic. Limited evidence exists about whether myopia development was reversed or worsened after the lockdown.

Objective

To determine the prevalence of myopia and its associated factors before, during, and after COVID-19 restrictions.

Design, Setting, and Participants

This population-based, repeated cross-sectional study evaluated children aged 6 to 8 years from the Hong Kong Children Eye Study between 2015 and 2021 in 3 cohorts: before COVID-19 (2015-2019), during COVID-19 restrictions (2020), and after COVID-19 restrictions were lifted (2021).

Exposures

All the children received ocular examinations, including cycloplegic autorefraction and axial length. Data about the children's lifestyle, including time spent outdoors, near-work time, and screen time, were collected from a standardized questionnaire.

Main Outcomes and Measures

The main outcomes were the prevalence of myopia, mean spherical equivalent refraction, axial length, changes in lifestyle, and the associated factors over 7 years. Data were analyzed using descriptive statistics, logistic regression, and generalized estimating equations.

Results

Of 20 527 children (mean [SD] age, 7.33 [0.89] years; 52.8% boys and 47.2% girls), myopia prevalence was stable from 2015 to 2019 (23.5%-24.9%; P = .90) but increased to 28.8% (P < .001) in 2020 and 36.2% (P < .001) in 2021. The mean (SD) time spent outdoors was much lower in 2020 (0.85 [0.53] h/d; P < .001) and 2021 (1.26 [0.48] h/d; P < .001) compared with pre-COVID-19 levels (1.40 [0.47]-1.46 [0.65] h/d). The trend was reversed for total near-work time and screen time. High myopia prevalence was associated with the COVID-19 pandemic (odds ratio [OR], 1.40; 95% CI, 1.28-1.54; P < .001), younger age (OR, 1.84; 95% CI, 1.76-1.93; P < .001), male sex (OR, 1.11; 95% CI, 1.03-1.21; P = .007), lower family income (OR, 1.05; 95% CI, 1.00-1.09; P = .04), and parental myopia (OR, 1.61; 95% CI, 1.52-1.70; P < .001). During the pandemic, mean (SD) near-work and screen times in children from lower-income families were 5.16 (2.05) h/d and 3.44 (1.97) h/d, more than from higher-income families (4.83 [1.85] and 2.90 [1.61] h/d, respectively).

Conclusions and Relevance

The findings of this cross-sectional study revealed that after COVID-19 restrictions were lifted in Hong Kong, myopia prevalence among children was higher than before the pandemic, and lifestyle did not return to pre-COVID-19 levels. Younger children and those from low-income families were at a higher risk of myopia development during the pandemic, suggesting that collective efforts for myopia control should be advocated for these groups.

Myopia control and prevention: From lifestyle to low-concentration atropine. The 2022 Josh Wallman Memorial Lecture

The purpose of this study was to explore the findings from the Hong Kong Children Eye Study and the Low Concentration Atropine for Myopia Progression (LAMP-1) Study. The incidence of myopia among schoolchildren in Hong Kong more than doubled during the COVID-19 pandemic, with outdoor time decreased significantly and screen time increased. The change in lifestyle during the COVID-19 pandemic aggravated myopia development. Low-concentration atropine (0.05%, 0.025% and 0.01%) is effective in reducing myopia progression with a concentration-related response. This concentration-dependent response was maintained throughout a 3-year follow-up period, and all low concentrations were well tolerated. An age-dependent effect was observed in each treatment group with 0.05%, 0.025% and 0.01% atropine. Younger age was associated with a poor treatment response to low-concentration atropine. Additionally, low-concentration atropine induced choroidal thickening along a concentration-dependent response throughout the treatment period. During the third year, continued atropine treatment achieved a better effect across all concentrations compared with the washout regimen. Stopping treatment at an older age and receiving lower concentration were associated with a smaller rebound effect. However, differences in the rebound effect were clinically small across all the three concentrations studied.

Effect of Low-Concentration Atropine Eyedrops vs Placebo on Myopia Incidence in Children: The LAMP2 Randomized Clinical Trial

Importance

Early onset of myopia is associated with high myopia later in life, and myopia is irreversible once developed.

Objective

To evaluate the efficacy of low-concentration atropine eyedrops at 0.05% and 0.01% concentration for delaying the onset of myopia.

Design, Setting, and Participants

This randomized, placebo-controlled, double-masked trial conducted at the Chinese University of Hong Kong Eye Centre enrolled 474 nonmyopic children aged 4 through 9 years with cycloplegic spherical equivalent between +1.00 D to 0.00 D and astigmatism less than -1.00 D. The first recruited participant started treatment on July 11, 2017, and the last participant was enrolled on June 4, 2020; the date of the final follow-up session was June 4, 2022.

Interventions

Participants were assigned at random to the 0.05% atropine (n = 160), 0.01% atropine (n = 159), and placebo (n = 155) groups and had eyedrops applied once nightly in both eyes over 2 years.

Main Outcomes and Measures

The primary outcomes were the 2-year cumulative incidence rate of myopia (cycloplegic spherical equivalent of at least -0.50 D in either eye) and the percentage of participants with fast myopic shift (spherical equivalent myopic shift of at least 1.00 D).

Results

Of the 474 randomized patients (mean age, 6.8 years; 50% female), 353 (74.5%) completed the trial. The 2-year cumulative incidence of myopia in the 0.05% atropine, 0.01% atropine, and placebo groups were 28.4% (33/116), 45.9% (56/122), and 53.0% (61/115), respectively, and the percentages of participants with fast myopic shift at 2 years were 25.0%, 45.1%, and 53.9%. Compared with the placebo group, the 0.05% atropine group had significantly lower 2-year cumulative myopia incidence (difference, 24.6% [95% CI, 12.0%-36.4%]) and percentage of patients with fast myopic shift (difference, 28.9% [95% CI, 16.5%-40.5%]). Compared with the 0.01% atropine group, the 0.05% atropine group had significantly lower 2-year cumulative myopia incidence (difference, 17.5% [95% CI, 5.2%-29.2%]) and percentage of patients with fast myopic shift (difference, 20.1% [95% CI, 8.0%-31.6%]). The 0.01% atropine and placebo groups were not significantly different in 2-year cumulative myopia incidence or percentage of patients with fast myopic shift. Photophobia was the most common adverse event and was reported by 12.9% of participants in the 0.05% atropine group, 18.9% in the 0.01% atropine group, and 12.2% in the placebo group in the second year.

Conclusions and Relevance

Among children aged 4 to 9 years without myopia, nightly use of 0.05% atropine eyedrops compared with placebo resulted in a significantly lower incidence of myopia and lower percentage of participants with fast myopic shift at 2 years. There was no significant difference between 0.01% atropine and placebo. Further research is needed to replicate the findings, to understand whether this represents a delay or prevention of myopia, and to assess longer-term safety.

Trial Registration

Chinese Clinical Trial Registry: ChiCTR-IPR-15006883.

Association of Maternal and Paternal Astigmatism With Child Astigmatism in the Hong Kong Children Eye Study

IMPORTANCE

Parental astigmatism is a factor associated with risk for development of child astigmatism; however, the magnitude of the association has not been determined.

OBJECTIVE

To determine the association between parental and child astigmatism.

DESIGN, SETTING, AND PARTICIPANTS

This population-based, cross-sectional study included participants from familial trios, each comprising a child aged 6 to 8 years and both parents, recruited from the Hong Kong Children Eye Study. No restriction criteria were set on the children in terms of refractive status. Data were analyzed from February to June 2022.

EXPOSURES

Cycloplegic autorefraction and autokeratometry were conducted on the children, whereas noncycloplegic autorefraction and autokeratometry were conducted on their parents. The children were categorized into 6 groups on the basis of the severity of astigmatism of both parents. Information on parental education, family income, and children's outdoor and near work time were obtained by questionnaires.

MAIN OUTCOMES AND MEASURES

The primary outcome was the odds of child astigmatism among the 6 categories of children. Associations of factors with child astigmatism were evaluated by logistic regression analyses.

RESULTS

A total of 17 124 participants from 5708 trios (2964 boys and 2754 girls) at a mean (SD) age of 7.32 (0.87) years, and 11 416 parents were examined. Astigmatism of 1.0 D or greater in both parents was associated with greater odds of refractive astigmatism (RA) (odds ratio [OR], 1.62; 95% CI, 1.15-2.26) and corneal astigmatism (CA) (OR, 1.94; 95% CI, 1.50-2.50) in the child. The respective ORs increased to 3.10 (95% CI, 1.34-7.21) and 4.31 (95% CI, 1.76-10.55) when both parents had astigmatism 2.0 D or greater. Higher parental astigmatism conferred higher risks for both RA and CA in children (P for trend <.001). Parental astigmatism was significantly associated with greater odds of corresponding child astigmatism (maternal RA: OR, 0.76; 95% CI, 0.68-0.84; paternal RA: OR, 0.82; 95% CI, 0.74-0.91; maternal CA: OR, 1.70; 95% CI, 1.51-1.93; paternal CA: OR, 1.33; 95% CI, 1.19-1.49).

CONCLUSIONS AND RELEVANCE

The findings of this cross-sectional study suggest that parental astigmatism may confer an independent and dose-dependent association with child astigmatism. Children with parents with astigmatism should have early eye examinations for timely detection of astigmatism to facilitate age-appropriate vision correction and visual development.

Myopia incidence and lifestyle changes among school children during the COVID-19 pandemic: a population-based prospective study

BACKGROUND

The impacts of social restrictions for COVID-19 on children's vision and lifestyle remain unknown.

AIMS

To investigate myopia incidence, spherical equivalent refraction (SER) and lifestyle changes among schoolchildren during the COVID-19 pandemic.

METHODS

Two separate longitudinal cohorts of children aged 6-8 years in Hong Kong were included. The COVID-19 cohort was recruited at the beginning of the COVID-19 outbreak, whereas the pre-COVID-19 cohort was recruited before the COVID-19 pandemic. All children received ocular examinations, and answered a standardised questionnaire relating to their lifestyle, including time spent on outdoor activities and near work, both at baseline and at follow-up visits.

RESULTS

A total of 1793 subjects were recruited, of whom 709 children comprised the COVID-19 cohort with 7.89±2.30 months of follow-up, and 1084 children comprised the pre-COVID-19 cohort with 37.54±3.12 months of follow-up. The overall incidence was 19.44% in the COVID-19 cohort, and 36.57% in pre-COVID-19 cohort. During the COVID-19 pandemic, the change in SER and axial length was -0.50±0.51 D and 0.29±0.35 mm, respectively; the time spent on outdoor activities decreased from 1.27±1.12 to 0.41±0.90 hours/day (p<0.001), while screen time increased from 2.45±2.32 to 6.89±4.42 hours/day (p<0.001).

CONCLUSIONS

We showed a potential increase in myopia incidence, significant decrease in outdoor time and increase in screen time among schoolchildren in Hong Kong during the COVID-19 pandemic. Our results serve to warn eye care professionals, and also policy makers, educators and parents, that collective efforts are needed to prevent childhood myopia-a potential public health crisis as a result of COVID-19.

Iris Depigmentation in the Prediction of Cytomegalovirus Anterior Uveitis

PURPOSE

We hypothesize that the presence of iris depigmentation is associated with the prediction of cytomegalovirus (CMV) as the etiology of chronic or recurrent anterior uveitis.

METHODS

A prospective cohort study on patients with recurrent or chronic anterior uveitis. Pre-operative data on iris depigmentation and corneal endothelial cell densities were compared between eyes with and without CMV.

RESULTS

Forty-one eyes of 38 subjects with a mean age of 61.1 ± 11.2 years old were recruited. Seventeen eyes were positive for CMV. A greater proportion of eyes with CMV showed severe or diffuse iris depigmentation than eyes without CMV, and possessed larger corneal endothelial cells (p = .028). When severe iris depigmentation was present with a reduced endothelial cell density, the positive and negative predictive values were raised to 100.0% and 64.9% from 41.5% and 58.5%, respectively.

CONCLUSION

Iris depigmentation is a potential clinical biomarker in predicting CMV in chronic or recurrent anterior uveitis.

The Association of Choroidal Thickening by Atropine With Treatment Effects for Myopia: Two-Year Clinical Trial of the Low-concentration Atropine for Myopia Progression (LAMP) Study

PURPOSE

To evaluate longitudinal changes in subfoveal choroidal thickness (SFChT) among children receiving atropine 0.05%, 0.025%, or 0.01% over 2 years and their associations with treatment outcomes in myopia control.

DESIGN

Double-blinded randomized controlled trial.

METHODS

SFChT was measured at 4-month intervals using spectral domain optical coherence tomography. Cycloplegic spherical equivalent (SE), axial length (AL), best-corrected visual acuity, parental SE, outdoor time, near work diopter hours, and treatment compliance were also measured.

RESULTS

314 children were included with qualified choroidal data. The 2-year changes in SFChT from baseline were 21.15 ± 32.99 µm, 3.34 ± 25.30 µm, and -0.30 ± 27.15 µm for the atropine 0.05%, 0.025%, and 0.01% groups, respectively (P < .001). A concentration-dependent response was observed, with thicker choroids at higher atropine concentrations (β = 0.89, P < .001). Mean SFChT thickness significantly increased at 4 months in the atropine 0.025% (P = .001) and 0.05% groups (P < .001) and then remained stable until the end of the second year (P > .05 for all groups). Over 2 years, an increase in SFChT was associated with slower SE progression (β = 0.074, P < .001) and reduced AL elongation (β = -0.045, P < .001). In the mediation analysis, 18.45% of the effect on SE progression from atropine 0.05% was mediated via its choroidal thickening.

CONCLUSIONS

Low concentration atropine induced a choroidal thickening effect along a concentration-dependent response throughout the treatment period. The choroidal thickening was associated with a slower SE progression and AL elongation among all the treatment groups. Choroidal response can be used for assessment of long-term treatment outcomes and as a guide for concentration titrations of atropine.

Diagnostic assessment of glaucoma and non-glaucomatous optic neuropathies via optical texture analysis of the retinal nerve fibre layer

The clinical diagnostic evaluation of optic neuropathies relies on the analysis of the thickness of the retinal nerve fibre layer (RNFL) by optical coherence tomography (OCT). However, false positives and false negatives in the detection of RNFL abnormalities are common. Here we show that an algorithm integrating measurements of RNFL thickness and reflectance from standard wide-field OCT scans can be used to uncover the trajectories and optical texture of individual axonal fibre bundles in the retina and to discern distinctive patterns of loss of axonal fibre bundles in glaucoma, compressive optic neuropathy, optic neuritis and non-arteritic anterior ischaemic optic neuropathy. Such optical texture analysis can detect focal RNFL defects in early optic neuropathy, as well as residual axonal fibre bundles in end-stage optic neuropathy that were indiscernible by conventional OCT analysis and by red-free RNFL photography. In a diagnostic-performance study, optical texture analysis of the RNFL outperformed conventional OCT in the detection of glaucoma, as defined by visual-field testing or red-free photography. Our findings show that optical texture analysis of the RNFL for the detection of optic neuropathies is highly sensitive and specific.

Association of SIX1-SIX6 polymorphisms with peripapillary retinal nerve fibre layer thickness in children

PURPOSE

Association of SIX1-SIX6 variants with peripapillary retinal nerve fibre layer (p-RNFL) thickness had been reported in adults. This study aimed to investigate these associations in children, with further explorations by spatial, age and sex stratifications.

METHODS

2878 school children aged between 6 and 9 years were enrolled from the Hong Kong Children Eye Study. Three single-nucleotide polymorphisms (SNPs) at the SIX1-SIX6 locus were genotyped. The association of each SNP with p-RNFL thickness (including global and sectoral thickness) were evaluated using multiple linear regression.

RESULTS

SNPs rs33912345 (p=7.7×10^-4) and rs10483727 (p=0.0013) showed significant associations with temporal-inferior p-RNFL thickness. The C allele of rs33912345 was associated with a thinner temporal-inferior p-RNFL by an average of 2.44 µm, while rs10483727-T was associated with a thinner temporal-inferior p-RNFL by 2.32 µm. The association with temporal-inferior p-RNFL was the strongest in the 8-9 year-old group for rs33912345 (p=5.2×10^-4) and rs10483727 (p=3.3×10^-4). Both SNPs were significantly associated with temporal-inferior p-RNFL thickness in boys (p<0.0017), but not in girls (p>0.05). In contrast, rs12436579-C (β=1.66; p=0.0059), but not rs33912345-C (β=1.31; p=0.052) or rs10483727-T (β=1.19; p=0.078), was nominally associated with a thicker nasal-inferior p-RNFL.

CONCLUSIONS

Both rs33912345 and rs10483727 at SIX1-SIX6 were associated with p-RNFL thickness in children, especially at the temporal-inferior sector, with age-dependent and sex-specific effects. SNP rs12436579 was associated with nasal-inferior p-RNFL thickness. Our findings suggested a role of SIX1-SIX6 in RNFL variation during neural retina development in childhood.

Delayed Diagnosis of Amblyopia in Children of Lower Socioeconomic Families: The Hong Kong Children Eye Study

AIMS

To determine the prevalence of amblyopia and the factors associated with delayed diagnosis among school-aged children in Hong Kong.

METHODS

Completed comprehensive ophthalmoscopic examinations were conducted among 4.273 children aged 6-8 years in the population-based Hong Kong Children Eye Study. New and previous diagnoses of amblyopia were identified. Socioeconomic status was surveyed through questionnaires.

RESULTS

According to criteria from the Multi-Ethnic Pediatric Eye Disease Study (MEPEDS), amblyopia was present in 43 out of 4,273 children (1.01%; 95% CI, 0.71-1.31). Among them, 33 (0.77%) were newly detected cases that were more likely from families living in Public Rental Housing or subdivided flats (OR, 4.22; P = .012), with lower paternal (OR 6.68, P = .008) and maternal education levels (OR, 4.38; P = .039). Multivariate analysis revealed associations of amblyopia with hyperopia (≥+2.00D; OR, 6.23; 95% CI, 2.86-13.56, P < .001), astigmatism (≥+2.00D; OR, 24.88; 95% CI, 10.69-57.91, P < .001) and anisometropia (≥2.00D; OR, 14.49; 95% CI, 5.93-37.63, P < .001).

CONCLUSION

These children with delayed diagnoses of amblyopia were more likely to come from lower socioeconomic backgrounds. Public education aimed at increasing awareness and utilization of child vision screening among such families is needed.

Diagnosing Paraproteinemic Keratopathy: A Case Report

A 65-year-old man presented with bilateral, painless, progressive blurring of vision over 9 years. Slit-lamp examination revealed bilateral subepithelial corneal opacities in clusters located at the mid-periphery. Anterior segment optical coherence tomography, in vivo confocal microscopy (IVCM), serum protein electrophoresis, and molecular genetic testing were performed to evaluate the cause of corneal opacities. Anterior segment optical coherence tomography revealed a band-like, hyperreflective lesion in the Bowman layer and anterior stroma of both corneas. IVCM revealed hyperreflective deposits in the epithelium, anterior stroma, and endothelium. Serum protein electrophoresis identified the presence of paraproteins (immunoglobulin kappa), and molecular genetic testing revealed absence of mutations in the transforming growth factor beta-induced gene (TGFBI) and collagen type XVII alpha 1 gene (COL17A1). The ocular diagnosis of paraproteinemic keratopathy eventually led to a systemic diagnosis of monoclonal gammopathy of undetermined significance by our hematologist/oncologist. Paraproteinemic keratopathy is a rare differential diagnosis in patients with bilateral corneal opacities and therefore may be misdiagnosed as corneal dystrophy or neglected as scars. In patients with bilateral corneal opacities of unknown cause, serological examination, adjunct anterior segment imaging, and molecular genetic testing play a role in establishing the diagnosis.

The association between attention-deficit/hyperactivity disorder and retinal nerve fiber/ganglion cell layer thickness measured by optical coherence tomography: a systematic review and meta-analysis

PURPOSE

Retinal nerve fiber/ganglion cell layer (RNFL/GCL) thickness measured using optical coherence tomography has been proposed as an ocular biomarker for children with attention-deficit/hyperactivity disorder (ADHD), but findings varied in different studies. This study aims to determine the association between RNFL/GCL thickness and ADHD in children by systematic review and meta-analysis.

METHODS

We performed a literature search in Embase, PubMed, Medline, Web of Science, and PsycINFO for relevant articles published up to February 29, 2020. All studies with original data comparing RNFL/GCL thickness in ADHD and healthy children were included. The Newcastle Ottawa Scale was used to assess bias risk and quality of evidence. Pooled estimates of the differences in thickness of RNFL or GCL between ADHD and healthy subjects were generated using meta-analysis with a random-effect model due to significant inter-study heterogeneity. Sensitivity analysis was also performed.

RESULTS

We identified four eligible studies involving a total of 164 ADHD and 150 control subjects. Meta-analysis revealed that ADHD in children was associated with a reduction in global RNFL thickness (SMD, - 0.23; 95% CI - 0.46, - 0.01; p = 0.04). The global GCL thickness was examined in two studies with 89 ADHD and 75 control subjects, but the pooled difference in global GCL thickness between ADHD children and controls was not statistically significant (SMD, - 0.34; 95% CI - 1.25, 0.58; p = 0.47).

CONCLUSION

Existing evidence suggests a possible association between ADHD and RNFL thinning in children. In view of the limited number of reports, further studies in large cohorts should be warranted.

Association of polymorphisms in ZFHX1B, KCNQ5 and GJD2 with myopia progression and polygenic risk prediction in children

AIMS

To assess the association of single-nucleotide polymorphisms (SNPs) with myopia progression for polygenic risk prediction in children.

METHODS

Six SNPs (ZC3H11B rs4373767, ZFHX1B rs13382811, KCNQ5 rs7744813, MET rs2073560, SNTB1 rs7839488 and GJD2 rs524952) were analysed in 1043 school children, who completed 3-year follow-up, using TaqMan genotyping assays. SNP associations with progression in spherical equivalent (SE) were analysed by logistic regression. Polygenic risk scores (PRS) were applied for computing the sum of the risk alleles of multiple SNPs corresponding to myopia progression, weighted by the effect sizes of corresponding SNPs.

RESULTS

GJD2 rs524952 showed significant association with fast progression (OR=1.32, 95% CI 1.10 to 1.59; p=0.003) and KCNQ5 rs7744813 had nominal association (OR=1.32, 95% CI 1.04 to 1.67; p=0.02). In quantitative traits locus analysis, GJD2 rs524952 and KCNQ5 rs7744813 were associated with progression in SE (β=-0.038 D/year, p=0.008 and β=-0.042 D/year, p=0.02) and axial elongation (β=0.016 mm/year, p=0.01 and β=0.017 mm/year, p=0.027). ZFHX1B rs13382811 also showed nominal association with faster progression in SE (β=-0.041 D/year, p=0.02). PRS analysis showed that children with the highest PRS defined by rs13382811, rs7744813 and rs524952 had a 2.26-fold of increased risk of fast myopia progression (p=4.61×10^-5). PRS was also significantly associated with SE progression (R²=1.6%, p=3.15×10^-5) and axial elongation (R²=1.2%, p=2.6×10^-4).

CONCLUSIONS

In this study, multi-tiered evidence suggested SNPs in ZFHX1B, KCNQ5 and GJD2 as risk factors for myopia progression in children. Additional attention and appropriate interventions should be given for myopic children with high-risk PRS as defined by GJD2 rs524952, KCNQ5 rs7744813 and ZFHX1B rs13382811.

Independent and Synergistic Effects of High Blood Pressure and Obesity on Retinal Vasculature in Young Children: The Hong Kong Children Eye Study

Background High blood pressure (BP) and obesity are becoming increasingly prevalent among children globally. Although prior studies have shown their adverse impacts on macrovascular health, less is known about their effects on microvascular heath. This study aims to evaluate the independent and synergistic effects of hypertensive BP and obesity on retinal vasculature in young children. Method and Results 1006 children aged 6 to 8 years were recruited from the Hong Kong Children Eye Study. Quantitative retinal vascular parameters, including central retinal arteriolar and venular equivalents and retinal arteriolar and venular fractal dimensions, were measured from retinal photographs following a standardized protocol. BP and body mass index were categorized according to reference values from American Academy of Pediatrics and International Obesity Task Force guidelines respectively. Children with hypertensive systolic BP had the narrowest central retinal arteriolar equivalents compared with children with either elevated or normotensive systolic BP (162.4, 164.6, and 167.1 µm; P-trend <0.001). Increased standardized systolic BP was associated with narrower central retinal arteriolar equivalents (β=-2.276 µm, P<0.001), wider central retinal venular equivalents (1.177, P=0.007), and decreased arteriolar fractal dimensions (β=-0.004, P=0.034). Children with obesity had the smallest arteriolar fractal dimensions compared with children with overweightness and normal weight (1.211, 1.234, and 1.240; P-trend=0.004). Children with both hypertensive BP and either overweightness or obesity had the narrowest central retinal arteriolar equivalents and smallest arteriolar D_f (P-trend<0.001 and P-trend=0.007). Conclusions Our findings demonstrate the potential synergistic or additive effects for both hypertensive BP and obesity on retinal vasculature in children.

A Systematic Review on Three Major Types of Scleral-Fixated Intraocular Lens Implantation

PURPOSE

We performed a systematic review on 3 major types of scleral-fixated intraocular lens (SFIOL) implantations and conducted subgroup analyses on pediatric population and subjects with Marfan syndrome.

DESIGN

Systematic review.

METHODS

We performed a search in PubMed, Ovid MEDLINE, and Embase for English language articles with keywords "(sutured intraocular lens) OR (SFIOL) OR (sutureless intraocular lens) OR (glued intraocular lens) OR (intrascleral intraocular lens) OR (SFIOL)" through October 16, 2019. Articles reporting individual outcomes after SFIOL were included in this systematic review. Recorded outcome measures included intraoperative and postoperative complications, endothelial cell changes, and intraocular lens-related outcomes.

RESULTS

Our search yielded 217 papers. After removing duplicated and irrelevant reports, we included 57 articles involving 2624 eyes. The mean age at operation was 51.47 ± 25.62 years. Sutured SFIOL was most commonly reported in all subjects with Marfan syndrome and 92.87% of pediatric patients. The pooled intraoperative complication rate was 6.65%. Minor anterior chamber hemorrhage was the most common intraoperative (1.92%) and postoperative complication (13.93%). Optic capture was the top intraocular lens (IOL)-related complication (4.47%). The overall mean endothelial cell loss was 8.95% at 16.77 ± 11.04 months. Overall 11.99% of SFIOLs were decentred with a mean distance of 0.49 ± 0.40 mm and a mean degree of tilt by 4.11 ± 3.03°.

CONCLUSIONS

Glued SFIOL had the fewest IOL-related complications and the lowest endothelial cell loss. Sutured SFIOL carried the highest IOL-related complications, whereas sutureless, glueless SFIOL was associated with the greatest endothelial cell loss.

Randomised assessormasked trial evaluating topical manuka honey (Optimel) in treatment of meibomian gland dysfunction

PURPOSE

To evaluate the effects of manuka honey eye-drops in the treatment of meibomian gland dysfunction.

METHODS

This is an assessor-masked (single-blind), randomised controlled trial comparing conventional treatment group with interventional group using Optimel 16% manuka honey topical eye-drops. 59 patients were recruited to the study and randomised into two groups: one given regular lubricants and the other given Optimel 16% manuka honey eye-drops. The Standard Patient Evaluation of Eye Dryness (SPEED) score was measured at baseline and on follow-up. 4 patients were lost to follow-up. Multiple ocular surface parameters were graded from slit lamp examination by a masked assessor. Results were compared from baseline to follow-up date 3 weeks later.

RESULTS

Patients in the conventional treatment group demonstrated minimal difference in SPEED score at 3-week follow-up (mean difference 1.087, p=0.183), which was not statistically significant. However, measurements of tear film break-up time, corneal surface stain (Oxford), lid margin, conjunctival redness, as well as meibum quality and expressibility showed significant improvements at 3 weeks (p<0.01). Patients in the manuka honey eye-drops group showed significant difference after 3 weeks in SPEED score (mean difference 2.53, p=0.006), as well as in lid margin redness, conjunctival redness, corneal surface stain (Oxford), and meibum quality and expressibility (p=0.000).

CONCLUSIONS

Optimel 16% manuka honey eye-drops showed significant improvement in symptoms and objective signs in meibomian gland dysfunction and are an effective alternative treatment for meibomian gland dysfunction.

TRIAL REGISTRATION NUMBER

NCT04457648.

Age Effect on Treatment Responses to 0.05%, 0.025%, and 0.01% Atropine: Low-Concentration Atropine for Myopia Progression Study

PURPOSE

To investigate the effect of age at treatment and other factors on treatment response to atropine in the Low-Concentration Atropine for Myopia Progression (LAMP) Study.

DESIGN

Secondary analysis from a randomized trial.

PARTICIPANTS

Three hundred fifty children aged 4 to 12 years who originally were assigned to receive 0.05%, 0.025%, or 0.01% atropine or placebo once daily, and who completed 2 years of the LAMP Study, were included. In the second year, the placebo group was switched to the 0.05% atropine group.

METHODS

Potential predictive factors for change in spherical equivalent (SE) and axial length (AL) over 2 years were evaluated by generalized estimating equations in each treatment group. Evaluated factors included age at treatment, gender, baseline refraction, parental myopia, time outdoors, diopter hours of near work, and treatment compliance. Estimated mean values and 95% confidence intervals (CIs) of change in SE and AL over 2 years also were generated.

MAIN OUTCOME MEASURES

Factors associated with SE change and AL change over 2 years were the primary outcome measures. Associated factors during the first year were secondary outcome measures.

RESULTS

In 0.05%, 0.025%, and 0.01% atropine groups, younger age was the only factor associated with SE progression (coefficient of 0.14, 0.15, and 0.20, respectively) and AL elongation (coefficient of -0.10, -0.11, and -0.12, respectively) over 2 years; the younger the age, the poorer the response. At each year of age from 4 to 12 years across the treatment groups, higher-concentration atropine showed a better treatment response, following a concentration-dependent effect (P_trend <0.05 for each age group). In addition, the mean SE progression in 6-year-old children receiving 0.05% atropine (-0.90 diopter [D]; 95% CI, -0.99 to -0.82) was similar to that of 8-year-old children receiving 0.025% atropine (-0.89 D; 95% CI, -0.94 to -0.83) and 10-year-old children receiving 0.01% atropine (-0.92 D; 95% CI, -0.99 to -0.85). All concentrations were well tolerated in all age groups.

CONCLUSIONS

Younger age is associated with poor treatment response to low-concentration atropine at 0.05%, 0.025%, and 0.01%. Among concentrations studied, younger children required the highest 0.05% concentration to achieve similar reduction in myopic progression as older children receiving lower concentrations.

Association of WNT7B and RSPO1 with Axial Length in School Children

Purpose

To evaluate the association between single-nucleotide polymorphisms (SNPs) in the ZC3H11B, RSPO1, C3orf26, GJD2, ZNRF3, and WNT7B genes and myopia endophenotypes in children.

Methods

Seven SNPs identified in previous genome-wide association studies of axial length (AL) were genotyped in 2883 Southern Han Chinese children. Multiple linear regression analyses were conducted to evaluate the genotype association with AL, spherical equivalent (SE), corneal curvature (CC), and central corneal thickness (CCT).

Results

Two SNPs-namely, rs12144790 in RSPO1 (allele T, P = 0.0066, β = 0.062) and rs10453441 in WNT7B (allele A, P = 8.03 × 10-6, β = 0.103)-were significantly associated with AL. The association of rs4373767 in ZC3H11B (allele C, P = 0.030, β = -0.053) could not withstand the correction for multiple testing. WNT7B rs10453441 showed a strong association with CC (P = 1.17 × 10-14, β = 0.053) and with CCT (P = 0.0026, β = 2.65). None of the tested SNPs was significantly associated with SE. The C allele of SNP rs12321 in ZNRF3 was associated with CC (P = 0.0060, β = -0.018).

Conclusions

This study revealed that the RSPO1 SNP rs12144790 was associated with AL, whereas WNT7B rs10453441 was associated with AL, CC, and CCT in children. A novel association between ZNRF3 rs12321 and CC was discovered. Our data suggest that the RSPO1 and WNT7B genes might exert their effects on multiple aspects of eye growth during childhood. Potential differences in the genetic profiles of AL between children and adults should be explored in larger cohorts.

A 5-year analysis of endothelial vs penetrating keratoplasty graft survival in Chinese patients

AIM

To determine if there is any difference in long term graft survival between Descemet's stripping endothelial keratoplasty (DSEK) and penetrating keratoplasty (PK).

METHODS

A retrospective 5-year cases analysis of bullous keratopathy secondary to Fuchs' endothelial dystrophy or pseudophakic bullous keratopathy, receiving either DSEK or PK. A total of 42 DSEK cases and 25 PK cases were included in the analysis.

RESULTS

In the 5-year analysis, graft survival rates were very similar in the two groups (DSEK 77.1% vs PK 76.0%, P=0.918, 95%CI: -6.3 to 33.4). Sub-analyses at 1y (DSEK 81% vs PK 95%, P=0.085, 95%CI: -29 to 3.6) and 2y (DSEK 81% vs PK 88%, P=0.381, 95%CI: -25.9 to 11.8) show a trend towards lower survival rates of DSEK vs PK, but the results were not statistically significant.

CONCLUSION

Long term 5-year graft survival is similar between the DSEK and PK methods of corneal transplant in Chinese patients with bullous keratopathy.

Genetic associations of myopia severities and endophenotypes in children

OBJECTIVE

To investigate the associations of multiple single-nucleotide polymorphisms (SNPs) with the severities and endophenotypes of myopia in children.

METHODS

A total of 3300 children aged 5-10 years were recruited: 137 moderate and high myopia (SE≤-3.0D), 670 mild myopia (-3.0D<SE≤-0.5D) and 2493 controls (SE>-0.5D). 13 SNPs in 13 genes/loci were selected for genotyping in all subjects using TaqMan assays. Associations between each SNP with myopia severities and ocular traits (spherical equivalent (SE), axial length (AL) and corneal radius (CR)) were analysed.

RESULTS

When compared with controls, SNPs ZC3H11B rs4373767 (OR=1.15, p=0.038), BICC1 rs7084402 (OR=1.18, p=0.005) and GJD2 rs524952 (OR=1.14, p=0.025) showed nominal associations with overall myopia. ZC3H11B rs4373767 and BICC1 rs7084402 showed stronger associations with moderate and high myopia (rs4373767: OR=1.42, p=0.018; rs7084402: OR=1.33, p=0.025), while GJD2 rs524952 had a stronger association with mild myopia (OR=1.14, p=0.025). GJD2 rs524952 also showed a difference between emmetropia and hyperopia (p=0.018). In quantitative trait locus analysis, ZC3H11B rs4373767, KCNQ5 rs7744813 and GJD2 rs524952 were correlated with both myopic SE (β=-0.09, p=0.03; β=-0.12, p=0.007; β=-0.13, p=0.0006, respectively) and AL (β=0.07, p=0.002; β=0.09, p=0.0008; β=0.07, p=0.0003, respectively). SNTB1 rs7839488 was correlated with both AL (β=0.07, p=0.005) and CR (β=0.02, p=0.006). Moreover, ZC3H11B rs4373767-T (β=0.006; p=0.018), KCNQ5 rs7744813-A (β=0.007; p=0.015) and GJD2 rs524952-T (β=0.009; p=0.0006) were correlated with AL-CR ratio.

CONCLUSIONS AND RELEVANCE

ZC3H11B and BICC1 are genetic risk factors for moderate and high myopia, while ZC3H11B, KCNQ5, SNTB1 and GJD2 confer risk to excessive AL in children.

High prevalence of myopia in children and their parents in Hong Kong Chinese Population: the Hong Kong Children Eye Study

PURPOSE

To determine the myopia prevalence in Hong Kong Chinese children and their parents.

METHODS

It was a population-based cross-sectional study. A total of 4257 children aged 6-8 years, and 5880 parents were recruited in the Hong Kong Children Eye Study. Cycloplegic autorefraction was measured for children; and non-cycloplegic autorefraction for parents. Parental educational level, children's outdoor time, and near work were collected by validated questionnaires.

RESULTS

In children aged 6-8 years, 25.0% were myopic, and among them, 12.7% for the 6-year-olds, 24.4% for the 7-year-olds and 36.1% for the 8-year-old. About 0.7% of children aged 8 years were high myopia. In all age groups, boys (their myopia rate: 13.9% at 6 years, 26.7% at 7 years, and 38.3% at 8 years) were more myopic than girls (11.3% at 6 years, 22.0% at 7 years, 33.4% at 8 years). Among parents, 72.2% were myopic (mother, 73.2%; father, 70.7%) and 13.5% high myopia (mother, 12.8%; father, 14.5%). It was observed that prevalence decreased with ages and increased with education level.

CONCLUSION

There is a strikingly high prevalence of myopia in Hong Kong children aged 6-8, much higher than that of other regions of China. Of note, the prevalence of children was similar to that in 15 years ago. Furthermore, the myopia prevalence of parents is high, and it had already increased in this cohort. Prevention of childhood myopia is important, likewise for visual complications from high myopia in adults.

Differential Effects on Ocular Biometrics by 0.05%, 0.025%, and 0.01% Atropine: Low-Concentration Atropine for Myopia Progression Study

PURPOSE

To evaluate changes in ocular biometrics in groups receiving 0.05%, 0.025%, and 0.01% atropine compared with placebo over 1 year based on the Low-Concentration Atropine for Myopia Progression (LAMP) study.

DESIGN

Double-blinded, randomized, placebo-controlled trial.

PARTICIPANTS

Three hundred eighty-three children aged 4 to 12 years who were assigned randomly to receive 0.05%, 0.025%, 0.01% atropine, or placebo once daily in both eyes and completed the first year of the LAMP study.

METHODS

Cycloplegic spherical equivalent (SE), axial length (AL), corneal curvature (K), and anterior chamber depth (ACD) were measured by IOLMaster. Corneal astigmatism and lens power were calculated. The ocular biometric parameter changes were compared among groups. Contributions to SE progression from ocular parameters were determined and compared among groups.

MAIN OUTCOME MEASURES

Changes in ocular biometrics and their associations with the changes in SE.

RESULTS

Over 1 year, changes in AL were 0.20 ± 0.25 mm, 0.29 ± 0.20 mm, 0.36 ± 0.29 mm, and 0.41 ± 0.22 mm in the 0.05% atropine, 0.025% atropine, 0.01% atropine, and placebo groups, respectively (P < 0.001), with a concentration-dependent response. Corneal power remained stable, and its changes were similar across all atropine concentrations: -0.02 ± 0.14 diopter (D), -0.01 ± 0.14 D, -0.01 ± 0.12 D, and 0.01 ± 0.14 D in the 0.05% atropine, 0.025% atropine, 0.01% atropine, and placebo groups, respectively (P = 0.10). Lens power decreased over time in each concentration, but its changes also were similar across all concentrations: -0.31 ± 0.43 D, -0.38 ± 0.47 D, -0.40 ± 0.43 D, and -0.41 ± 0.43 D in the 0.05% atropine, 0.025% atropine, 0.01% atropine, and placebo groups, respectively (P = 0.24). Changes in ACD remained similar across all concentrations (P = 0.41). The contributions to SE progression from the ocular biometric changes after adjusting for age and gender in each concentration were similar across all groups (P > 0.05).

CONCLUSIONS

Low-concentrations of atropine (0.05%, 0.025%, and 0.01%) have no clinical effect on corneal or lens power. Antimyopic effects of low-concentration atropine act mainly on reducing AL elongation, and therefore could reduce the risk of subsequent myopia complications.

Fifteen-year results of a randomized controlled trial comparing 0.02% mitomycin C, limbal conjunctival autograft, and combined mitomycin C with limbal conjunctival autograft in recurrent pterygium surgery

PURPOSE

To compare the long-term outcomes of recurrent pterygium surgery between three different techniques.

METHODS

We performed a 15-year follow-up study of a randomized controlled study on surgical management of recurrent pterygium. Group 1 received limbal conjunctival autograft (LCAU); group 2 received intraoperative mitomycin C (MMC) 0.02% for 5 min; and group 3 received combined LCAU + MMC 0.02% for 5 min. Consecutive patients enrolled in the original study (from April 2001 to March 2003) were invited back for a detailed clinical examination to document the long-term outcomes. The main outcome measures included the recurrence rate, residual conjunctival bed status, and complications from any of the surgical methods.

RESULTS

Sixty-two patients were recruited in the original study. Eight patients had passed away and 12 patients were uncontactable or not responded. One patient who had bilateral operations refused to return for follow-up and one eye had insufficient data for analysis. Finally, 40 eyes of 40 patients were included for analyses. One eye developed a recurrence over 15 years and none required a tertiary pterygium operation. The patient received LCAU for a temporal recurrent pterygium developed a 2.2-mm recurrence.

CONCLUSIONS

All three techniques yielded favorable outcomes for patients with recurrent pterygium. The use of LCAU was associated with better cosmetic outcome.

Characterization of ocular and nasopharyngeal microbiome in allergic rhinoconjunctivitis

BACKGROUND

Allergic rhinoconjunctivitis (ARC) is a prevalent allergic condition in the pediatric population. Microbial dysbiosis has increasingly been recognized to influence on host immunity and allergic diseases. However, the microbial profile of ARC has not been characterized. This cross-sectional study aims to evaluate the changes in nasal and ocular surface microbiome of children with ARC.

METHODS

Ocular and nasopharyngeal swabs were collected from controls and pediatric ARC cases for 16S rRNA amplicon sequencing. The bacterial community profile was analyzed. The correlation of the microbial diversity with the ARC-related clinical scores was studied.

RESULTS

A total of 23 patients with ARC and 17 healthy controls were recruited;30 were ocular samples (15 controls vs 15 ARC), while 40 were nasal samples (17controls vs 23 ARC) The alpha diversity of nasopharyngeal microbiome was significantly higher in ARC patients than healthy controls (P < 0.01), but not for ocular microbiome. The clinical scores in all subjects were negatively correlated with the Shannon diversity for ocular (P = 0.014) and positively correlated with nasopharyngeal (P = 0.010) microbiome. While the ocular microbiome remained significantly distinct from nasopharyngeal microbiome in terms of both alpha and beta diversity in both healthy subjects and ARC patients, significant differences of relative abundance of certain phyla (Bacteroidetes, Cyanobacteria, and Deinococcus-Thermus) and genera (Dolosigranulum and Moraxella) between nasal and ocular surfaces were only detected in healthy controls, but not in the ARC subjects, suggesting the microbial composition at both body sites becoming more similar at disease state.

CONCLUSION

This study reported (a) a higher alpha diversity in ocular than nasopharyngeal microbiome in both ARC patients and controls, and (b) nasopharyngeal microbiome became more diverse in ARC patients than in controls. Our results suggested an interaction of the microbiome between ocular and nasal compartments in patients with ARC.

Association of the ZC3H11B, ZFHX1B and SNTB1 genes with myopia of different severities

OBJECTIVE

To investigate the associations of single-nucleotide polymorphisms (SNPs) in the ZC3H11B, ZFHX1B, VIPR2, SNTB1 and MIPEP genes with severities of myopia in Chinese populations.

METHODS

Based on previous myopia genome-wide association studies, five SNPs (ZC3H11B rs4373767, ZFHX1B rs13382811, VIPR2 rs2730260, SNTB1 rs7839488 and MIPEP rs9318086) were selected for genotyping in a Chinese cohort of 2079 subjects: 252 extreme myopia, 277 high myopia, 393 moderate myopia, 366 mild myopia and 791 non-myopic controls. Genotyping was performed by TaqMan assays. Allelic frequencies of the SNPs were compared with myopia severities and ophthalmic biometric measurements.

RESULTS

The risk allele T of ZC3H11B SNP rs4373767 was significantly associated with high myopia (OR=1.39, p=0.007) and extreme myopia (OR=1.34, p=0.013) when compared with controls, whereas ZFHX1B rs13382811 (allele T, OR=1.33, p=0.018) and SNTB1 rs7839488 (allele G, OR=1.71, p=8.44E-05) were significantly associated with extreme myopia only. In contrast, there was no significant association of these SNPs with moderate or mild myopia. When compared with mild myopia, subjects carrying T allele of rs4373767 had a risk of progressing to high myopia (spherical equivalent ≤-6 dioptres) (OR=1.29, p=0.017). Similarly, the T allele of rs13382811 also imposed a significant risk to high myopia (OR=1.36, p=0.007). In quantitative traits analysis, SNPs rs4373767, rs13382811 and rs7839488 were correlated with axial length and refractive errors.

CONCLUSIONS

We confirmed ZC3H11B as a susceptibility gene for high and extreme myopia, and ZFHX1B and SNTB for extreme myopia in Chinese populations. Instead of myopia onset, these three genes were more likely to impose risks of progressing to high and extreme myopia.

Amniotic Membrane Transplant for Bullous Keratopathy: Confocal Microscopy & Anterior Segment Optical Coherence Tomography

PURPOSE

To assess amniotic membrane retention after amniotic membrane transplant in bullous keratopathy patients and whether there were any corneal structural changes that may hinder further penetrating keratoplasty Methods: A retrospective study including 22 patients who have undergone amniotic membrane transplant from 1 Jan 1998 till 30 Jun 2016. Confocal microscopy and anterior segment optical coherence tomography (ASOCT) were performed to assess the retention of amniotic membrane and to detect any corneal structural changes. The comparison was made with 5 controls who had bullous keratopathy awaiting endothelial keratoplasty.

RESULTS

Patients had a mean follow-up of 61 ± 33.7 months. Pain reduction was significant (p < .001) although it did not significantly correlate with the regularity of the superficial, intermediate or basal epithelial layers, nor with the retention of the amniotic membrane. No long-term structural changes that may hinder future penetrating keratoplasty were detected.

CONCLUSION

This procedure is a safe and effective long-term treatment for symptomatic bullous keratopathy patients.

Limbal ischemia: Reliability of clinical assessment and implications in the management of ocular burns

Purpose:

Limbal ischemia is an important prognostic factor in the management of ocular burns. In this study, we evaluated the reliability of clinically assessing limbal ischemia among ophthalmic professionals.

Methods:

This study included 111 ophthalmic professionals who were shown 12 diffuse illumination color slit-lamp photographs of eyes with recent chemical injuries. Respondents were asked whether the photos were assessable and if yes, then to indicate the presence, location, and grade of limbal ischemia in each case. The responses were collected using a standard data collection sheet and the inter-observer agreement was calculated.

Results:

All participants responded to every question. Of the 1,332 responses, images were deemed assessable in 1,222 (91.7%) instances. The overall agreement (Fleiss’ kappa) for the presence of limbal ischemia and severity of limbal ischemia was 0.106 and 0.139, respectively (P < 0.012). Among the four groups of observers, practicing cornea specialists displayed significantly (P < 0.003) higher kappa values (0.201–0.203) when compared to residents (0.131–0.185), fellows (0.086–0.127), and optometrists (0.077–0.102). All indicated a poor level of inter-rater consistency.

Conclusion:

The results indicate that clinical assessment of limbal ischemia is highly subjective and there is lack of reliability even among cornea specialists who regularly manage patients with ocular burns. A non-invasive, standardized, objective, accurate, and reliable modality for ocular surface angiography is desperately needed for proper assessment and prognostication of ocular burns.

Analysis of multiple genetic loci reveals MPDZ-NF1B rs1324183 as a putative genetic marker for keratoconus

OBJECTIVE

To investigate the associations between 16 single-nucleotide polymorphisms (SNPs) in 14 genetic loci and keratoconus in an independent Chinese cohort.

METHODS

This cross-sectional, case-control association study included a Chinese cohort of 133 patients with keratoconus and 371 control subjects. In a recent meta-analysis study, we identified association of 16 SNPs in 14 gene loci with keratoconus. In this study, we genotyped these 16 SNPs in all the patients and controls and analysed their association with keratoconus, its clinical severities and progression profiles. We also analysed the genotype-phenotype correlation between individual SNPs and steep keratometry, flat keratometry (Kf), average keratometry (Avg K) and best-fit sphere diameter (BFS) of the anterior and posterior corneal surface.

RESULTS

Among the 16 selected SNPs, rs1324183 in the MPDZ-NF1B locus showed a significant association with keratoconus (OR=2.22; 95% CI 1.42 to 3.45, p=4.30×10^-4), especially severe keratoconus (OR=5.10, 95% CI 1.63 to 15.93, p=0.005). The rs1324183 A allele was positively associated with anterior Kf (p=0.008), anterior Avg K (p=0.017), posterior Kf (p=0.01) and negatively associated with apex pachymetry (p=0.007) and anterior BFS (p=0.023) in keratoconus. The other 15 SNPs had no significant association with keratoconus or genotype-phenotype correlations.

CONCLUSIONS

This study confirmed the association of SNP rs1324183 in MPDZ-NF1B with keratoconus and revealed the association of this SNP with keratoconus severity and corneal parameters. It is thus a putative genetic marker for monitoring the progression of keratoconus to a severe form and facilitating early intervention.

Novel grid and sectoral analyses in monitoring corneal scars

PURPOSE

We aim to design two sampling methods, the grid and sectoral methods, to provide more precise detection of focal corneal scar changes with time following pterygium excision with the Pentacam imaging system.

METHODS

This is a retrospective study of our previous prospective observational case series. Thirty patients underwent primary pterygium excision with adjuvant topical mitomycin-C application were followed up and imaged with Pentacam system at postoperative weeks 1, 4, 12 and month 18. Grid and sectoral methods were used to sample density changes (in grayscale units, GSU) over the scarred areas as well as the clear pole of the same cornea.

RESULTS

Using the grid method, the average corneal densities were 39.4, 37.1, 36.7 and 34.7 GSU at postoperative 1, 4, 12 weeks and 18 months, respectively. On the other hand, using the sectoral method, the average corneal densities were 35.3, 33.3, 32.5 and 31.9 GSU at postoperative 1, 4, 12 weeks and 18 months, respectively. Paired t tests achieved statistical significance when comparing all follow-up time points to first postoperative visit. A statistically significant effect of time on the average density was shown on ANOVA (p < 0.001) using both analyses over the scarred areas, but not over the clear pole of the same cornea (p > 0.05).

CONCLUSION

Our novel approach to monitor corneal density changes using the grid or sectoral sampling methods seemingly enhances the power in monitoring density changes in corneal scars when compared to conventional total-diameter average densitometry.

Association of the PAX6 gene with extreme myopia rather than lower grade myopias

Aims

To investigate the association of the paired box gene 6 (PAX6) with different severities of myopia.

Methods

A total of four haplotype-tagging single-nucleotide polymorphisms (SNPs; rs2071754, rs3026354, rs3026390 and rs628224) and two previously reported SNPs (rs644242 and rs662702) in the PAX6 gene were analysed in a Hong Kong Chinese cohort of 1288 myopia subjects (including 252 extreme myopia, 277 high myopia, 393 moderate myopia and 366 mild myopia) and 791 no myopia controls. Allelic association analyses were performed for individual SNPs in different subgroups of myopia and in combined myopia, followed by a meta-analysis of our current data with reported data on PAX6 in myopia.

Results

The association of tagging SNPs rs2071754 and rs644242 with extreme myopia could not withstand multiple correction (rs2071754: OR=1.25, P value=0.031; rs644242: OR=1.33, P value=0.032). In the meta-analysis, rs644242 showed an enhanced, significant association with extreme myopia (OR=1.27, 95% CI 1.10 to 1.46, P value=0.001; I2=0%). In contrast, there was no significant association between the PAX6SNPs and high, moderate or mild myopia. No linear correlation was found between the PAX6SNPs and axial length.

Conclusion

This study provides additional evidence suggesting that the PAX6 SNP rs644242 is associated with extreme myopia but not lower grade myopia. Thus, PAX6 may be implicated in the development or progression into severe myopia. Further longitudinal studies are warranted.