Differences in corneal parameters between normal tension glaucoma and primary open-angle glaucoma.

The purpose of this study was to identify the differences in corneal parameters between medically treated normal tension glaucoma (NTG) and primary open-angle glaucoma (POAG) subjects. This cross-sectional study from September 2011 to September 2012 included consecutive subjects with POAG and NTG who were receiving topical anti-glaucoma medications at the time of the study. Subjects were excluded if they had pre-existing corneal pathology or scars and previous glaucoma lasers. The following parameters were compared between the NTG and POAG groups: endothelial cell count, central corneal thickness (CCT), spherical equivalent, presenting and current intraocular pressure (IOP), number and type of anti-glaucoma medication, retinal nerve fibre layer thickness, visual field index, visual acuity, and phakic status. Only the right eye was used for statistical analysis. The right eye of the 30 NTG and 28 POAG subjects had comparable baseline characteristics, post-treatment IOP, and glaucoma severity. The endothelial cell count was significantly lower in the NTG versus the POAG group (2,380.0 ± 315.4 vs. 2,530.0 ± 320.4 cells/mm(2), p = 0.04). There were no significant differences in the spherical equivalent or CCT between the NTG and POAG groups. A significantly lower corneal endothelial cell count was found in NTG compared to POAG.

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

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

Ophthalmic manifestations and risk factors for mortality of HIV patients in the post-highly active anti-retroviral therapy era.

BACKGROUND: To evaluate the ophthalmic manifestations and risk factors for mortality in HIV patients in the post-highly active anti-retrovirus therapy (HAART) era. DESIGN: Retrospective study. SAMPLES: 151 patients with HIV infection. METHODS: Review of all HIV patients who have attended the Hong Kong Eye Hospital between 2000 and 2007. MAIN OUTCOME MEASURES: Ocular findings especially opportunistic infections and medical information including mortality during follow up. RESULTS: At presentation, 139 (92.1%) patients were already diagnosed with HIV and 58 (41.7%) had an AIDS indicator condition. Fifty-one (33.8%) patients had HIV-related eye disease on presentation and the leading manifestations were cytomegalovirus (CMV) retinitis and HIV microangiopathy. Low baseline CD4 cell count <100 cells/L was significantly related with HIV-related ophthalmic manifestations and CMV retinitis at presentation (P < 0.013). 105 patients were followed for 6 months or more and the mean follow-up was 4.8 years. There was no significant change in visual acuity compared with baseline (P = 0.13). 20 (19.0%) patients had one eye with final visual acuity of 20/200 or worse and the leading cause for poor vision was CMV retinitis. 11 (10.5%) patients died during the follow-up due to complications of HIV/AIDS. The presence of HIV retinal microangiopathy was significantly associated with mortality (P = 0.005). CONCLUSIONS: CMV retinitis remains the main HIV-related ocular disease in the post-HAART era. HIV retinal microangiopathy might be an important prognostic factor for mortality. Appropriate ophthalmic monitoring is justified to detect for ophthalmic complications in HIV patients regardless of HAART use in order for prompt initiation of treatment.

The Contemporary Role of Photodynamic Therapy in the Treatment of Pachychoroid Diseases.

Recent advances in retinal imaging technology have improved our understanding in the pathogenesis and evolvement of various chorioretinal diseases. Central serous chorioretinopathy and polypoidal choroidal vasculopathy are now recognized to belong to the same spectrum of disorders known as pachychoroid diseases. Pachychoroid diseases have similar pathogenesis pathway and common characteristics of thickened choroid, dilated outer choroidal vessels, and thinning of choriocapillaris. More disease entities have been identified to belong to this disease spectrum. Photodynamic therapy can induce choroidal hypoperfusion, remodeling of abnormal choroidal vessels, and reduction of choroidal congestion. It is known to be an effective treatment for chronic central serous chorioretinopathy and polypoidal choroidal vasculopathy. Many new studies are being performed to investigate its efficacy in other pachychoroid diseases. In this review, we provided an overview of the rationale, efficacy, and treatment strategies of photodynamic therapy in different pachychoroid diseases and discussed its role in the management along with other treatment modalities with most updated clinical evidence.

COVID-19: Update on Its Ocular Involvements, and Complications From Its Treatments and Vaccinations.

ABSTRACT: The coronavirus disease 2019 (COVID-19) came under the attention of the international medical community when China first notified the World Health Organization of a pneumonia outbreak of then-unknown etiology in Wuhan in December 2019. Since then, COVID-19 caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has appalled the world by spreading at a pandemic speed. Although ophthalmologists do not directly engage in the clinical care of COVID-19 patients, the ophthalmology community has become aware of the close ties between its practice and the pandemic. Not only are ophthalmologists at heightened risk of SARS-CoV-2 exposure due to their physical proximity with patients in routine ophthalmic examinations, but SARS-CoV-2 possesses ocular tropism resulting in ocular complications beyond the respiratory tract after viral exposure. Furthermore, patients could potentially suffer from adverse ocular effects in the therapeutic process. This review summarized the latest literature to cover the ophthalmic manifestations, effects of treatments, and vaccinations on the eye to aid the frontline clinicians in providing effective ophthalmic care to COVID-19 patients as the pandemic continues to evolve.

Novel and homozygous BEST1 mutations in Chinese patients with Best vitelliform macular dystrophy.

PURPOSE: The purpose of this study was to investigate the BEST1 gene mutations in Chinese patients with Best vitelliform macular dystrophy (BVMD). METHODS: Twenty-six subjects from 7 Chinese families with BVMD and 100 unrelated healthy Chinese subjects without a family history of BVMD were screened for mutations in the BEST1 gene by direct sequencing. The subjects underwent complete ophthalmologic examination and BEST1 gene screening. RESULTS: Six novel missense mutations (Thr2Asn, Leu75Phe, Ser144Asn, Arg255Trp, Pro297Thr, and Asp301Gly) and 1 previously reported mutation (Arg218Cys) were identified. Each family was found to have a unique BEST1 mutation that segregated with the disease. Two of the six novel mutations are located within the four previously reported common mutation clusters within the BEST1 gene. One family with patients having homozygous Leu75Phe mutations did not have the more severe BVMD phenotype. None of the patients with mutations was identified among the 100 healthy control subjects. CONCLUSION: A large number of unique novel missense mutations was found in Chinese patients with BVMD, suggesting considerable interethnic differences between the mutation sites in the BEST1 gene in different populations. The few truncating BEST1 mutations and the lack of a more severe phenotype in homozygous patients suggest that the missense BEST1 mutation may produce a dominant negative effect on wild-type BEST1 gene.

Incorporating Optical Coherence Tomography Macula Scans Enhances Cost-effectiveness of Fundus Photography-Based Screening for Diabetic Macular Edema.

OBJECTIVE: To compare four screening strategies for diabetic macular edema (DME). RESEARCH DESIGN AND METHODS: Patients attending diabetic retinopathy screening were recruited and received macular optical coherence tomography (OCT), in addition to visual acuity (VA) and fundus photography (FP) assessments, as part of the standard protocol. Two retina specialists provided the reference grading by independently assessing each subject's screened data for DME. The current standard protocol (strategy A) was compared for sensitivity, specificity, quality-adjusted life-year (QALY) gained, and incremental cost-effectiveness ratio (ICER) with three alternative candidate protocols using a simulation model with the same subjects. In strategy B, macular hemorrhage or microaneurysm on FP were removed as surrogate markers for possible DME. Strategy C used best-corrected instead of habitual/pinhole VA and added central subfield thickness (CST) >290 µm on OCT in suspected cases as a confirmation marker for possible DME. Strategy D used CST >290 µm OCT in all subjects as a surrogate marker for suspected DME. RESULTS: We recruited 2,277 subjects (mean age 62.80 ± 11.75 years, 43.7% male). The sensitivities and specificities were 40.95% and 86.60%, 22.86% and 95.63%, 32.38% and 100%, and 74.47% and 98.34% for strategies A, B, C, and D, respectively. The costs (in U.S. dollars) of each QALY gained for strategies A, B, C, and D were $7,447.50, $8,428.70, $5,992.30, and $4,113.50, respectively. CONCLUSIONS: The high false-positive rate of the current protocol generates unnecessary referrals, which are inconvenient for patients and costly for society. Incorporating universal OCT for screening DME can reduce false-positive results by eightfold, while improving sensitivity and long-term cost-effectiveness.

COVID-19: Ocular Manifestations and the APAO Prevention Guidelines for Ophthalmic Practices.

The World Health Organization declared the Coronavirus Disease 2019 (COVID-19) caused by Severe Acute Respiratory Syndrome Coronavirus 2 a "Pandemic" on March 11, 2020. As of June 1, 2020, Severe Acute Respiratory Syndrome Coronavirus 2 has infected >6.2 million people and caused >372,000 deaths, including many health care personnel. It is highly infectious and ophthalmologists are at a higher risk of the infection due to a number of reasons including the proximity between doctors and patients during ocular examinations, microaerosols generated by the noncontact tonometer, tears as a potential source of infection, and some COVID-19 cases present with conjunctivitis. This article describes the ocular manifestations of COVID-19 and the APAO guidelines in mitigating the risks of contracting and/or spreading COVID-19 in ophthalmic practices.

Advances in Retinal Imaging and Applications in Diabetic Retinopathy Screening: A Review.

Rising prevalence of diabetes worldwide has necessitated the implementation of population-based diabetic retinopathy (DR) screening programs that can perform retinal imaging and interpretation for extremely large patient cohorts in a rapid and sensitive manner while minimizing inappropriate referrals to retina specialists. While most current screening programs employ mydriatic or nonmydriatic color fundus photography and trained image graders to identify referable DR, new imaging modalities offer significant improvements in diagnostic accuracy, throughput, and affordability. Smartphone-based fundus photography, macular optical coherence tomography, ultrawide-field imaging, and artificial intelligence-based image reading address limitations of current approaches and will likely become necessary as DR becomes more prevalent. Here we review current trends in imaging for DR screening and emerging technologies that show potential for improving upon current screening approaches.

Prevalence of Ocular Manifestations and Visual Outcomes in Patients With Herpes Zoster Ophthalmicus.

PURPOSE: To investigate the prevalence of ocular manifestations and visual outcomes in patients with herpes zoster ophthalmicus (HZO). METHODS: Consecutive cases diagnosed with HZO who attended 2 hospitals between July 1, 2011, and June 30, 2015, were retrospectively reviewed. Patient demographics, clinical presentations, and management were reviewed. The logistic regression model was used to estimate the odds ratio of visual loss with ocular manifestations. RESULTS: A total of 259 patients were included. Of these, 110 (42.5%) patients were <60 years old and 149 patients (57.5%) were ≥60 years old. None of the patients had received zoster vaccination before presentation. Ocular manifestations were present in 170 (65.6%) patients with no difference between both age groups (P = 0.101). Conjunctivitis was the most common ocular manifestation, followed by anterior uveitis and keratitis. After resolution of HZO, 58.7% of patients had a visual acuity of 6/12 or worse. Epithelial keratitis and stromal keratitis were independent risk factors for visual loss after resolution of HZO (P = 0.003 and P = 0.004, respectively). The corresponding odds ratio was 6.59 [95% confidence interval (CI): 1.87-23.19] and 7.55 (95% CI: 1.88-30.30), respectively. The number of ocular manifestations was also associated with an increased risk of visual loss with an odds ratio of 1.49 (95% CI: 1.01-2.20; P = 0.043). CONCLUSIONS: A substantial proportion of patients with HZO were <60 years old in this study. The absence of zoster vaccination across the study cohort was noteworthy. Keratitis was the main reason for poor visual outcome in these patients.

Correlation of Intraocular Pressure Between Both Eyes After Bilateral Selective Laser Trabeculoplasty in Open-angle Glaucoma.

PURPOSE: To investigate the correlation of intraocular pressure (IOP)-lowering effects of selective laser trabeculoplasty (SLT) between the 2 eyes treated with SLT in open-angle glaucoma (OAG). METHODS: This prospective cohort study sequentially recruited subjects with bilateral OAG. All subjects received a single session of 360-degree SLT treatment. Success was defined as IOP reduction of ≥20%. Spearman correlation was used to compare the following parameters between the 2 eyes following SLT: IOP at day 1, 1 week, and 1 month; percentage of success; and IOP reduction. RESULTS: In 84 eyes of 42 subjects that received bilateral SLT treatment, both eyes had statistically comparable baseline characteristics. There were significant correlations between the IOP in both eyes at all time intervals following SLT as well as for the percentage of IOP reduction and the success rate at 1 month after SLT (all r≥0.7, P<0.0001). A total of 42.9% of subjects had bilateral success and 38.1% had bilateral nonsuccess with a significant correlation between both eyes in these 2 groups (Spearman r>0.6, P<0.02). Nineteen percent had success in 1 eye and nonsuccess in the fellow eye with an inverse correlation between the 2 eyes (Spearman r=-0.7, P=0.03). CONCLUSION: There is a strong and significant correlation in the IOP-lowering response to SLT between both eyes in near 80% of treated OAG subjects, whereas near 20% had an asymmetrical and inverse response to SLT between both the eyes.

Risk of recurrence of retinopathy of prematurity after initial intravitreal ranibizumab therapy.

We report our experience with the use of intravitreal ranibizumab for the treatment of retinopathy of prematurity (ROP). A retrospective review was performed on 138 consecutive infants screened at a single centre over 18 months. Intravitreal ranibizumab was offered in selected cases requiring treatment, such as aggressive posterior ROP or poor mydriasis. 2 eyes of 1 infant received intravitreal ranibizumab alone and 8 eyes of 5 infants received combined intravitreal ranibizumab and laser therapy. 3 out of 8 eyes treated initially with intravitreal ranibizumab monotherapy had persistent disease requiring laser therapy, and 3 out of 5 eyes with initial regression suffered disease recurrence at a mean of 7.6 weeks post-injection. 2 eyes treated first with laser followed by intravitreal ranibizumab had disease regression without recurrence. Our cohort demonstrate a significant rate of persistent disease and recurrence in ROP eyes treated initially with intravitreal ranibizumab monotherapy, which is greater and earlier than that reported for intravitreal bevacizumab in the BEAT-ROP study. Intravitreal ranibizumab may be useful as an initial treatment in selected cases of ROP when laser therapy as first line is suboptimal. However, close monitoring is important and adjunctive laser therapy may subsequently be needed in a majority of cases.

Long-Term Outcome of Half-Dose Verteporfin Photodynamic Therapy for the Treatment of Central Serous Chorioretinopathy (An American Ophthalmological Society Thesis).

PURPOSE: To evaluate whether half-dose verteporfin photodynamic therapy (PDT) is better than natural history for the treatment of central serous chorioretinopathy (CSC). METHODS: Retrospective review of consecutive CSC patients treated with half-dose verteporfin PDT or untreated with observation and a minimum follow-up of 36 months. The main outcome measures included mean change in visual acuity and CSC recurrence. Survival analysis was performed to compare the CSC recurrence rates between the two groups. RESULTS: A total of 192 eyes of 192 patients were included; 75 eyes were treated with half-dose verteporfin PDT and 117 were untreated. The mean follow-up duration was 74.1 months. At the last follow-up, the mean logMAR visual acuity was significantly better in the half-dose verteporfin PDT group compared with the untreated control group (P=.005). The mean visual improvement of the half-dose verteporfin PDT group at the last follow-up was 1.8 lines, compared with 0.0 line in the untreated control group (P<.001). Recurrence of CSC developed in 15 eyes (20%) in the half-dose verteporfin PDT group compared with 63 eyes (53.8%) in the untreated control group (P<.001). Survival analysis demonstrated that eyes treated with half-dose verteporfin PDT were significantly less likely to develop CSC recurrence compared with untreated controls (P<.001). Regression analysis showed that half-dose verteporfin PDT was the only significant factor in reducing the risk of CSC recurrence. CONCLUSIONS: Half-dose verteporfin PDT for the treatment of CSC resulted in significantly better visual acuity outcomes and lower recurrence rate in the long term compared with untreated controls.

Relationship between Outer Retinal Layers Thickness and Visual Acuity in Diabetic Macular Edema.

PURPOSE: To investigate the correlation of outer retinal layers (ORL) thickness and visual acuity (VA) in patients with diabetic macular edema (DME). METHODS: Consecutive DME patients seen at the Retina Clinic of The University of Hong Kong were recruited for OCT assessment. The ORL thickness was defined as the distance between external limiting membrane (ELM) and retinal pigment epithelium (RPE) at the foveal center. The correlation between total retinal thickness, ORL thickness, and vision was calculated. RESULTS: 78 patients with DME were recruited. The mean age was 58.1 years (±11.5 years) and their mean visual acuity measured with Snellen chart was 0.51 (±0.18). The correlation coefficient between total retinal thickness and visual acuity was 0.34 (P < 0.001) whereas the correlation coefficient was 0.65 between ORL thickness and visual acuity (P < 0.001). CONCLUSION: ORL thickness correlates better with vision than the total retinal thickness. It is a novel OCT parameter in the assessment of DME. Moreover, it could be a potential long term visual prognostic factor for patients with DME.

Twelve-Year Outcomes of Pterygium Excision with Conjunctival Autograft versus Intraoperative Mitomycin C in Double-Head Pterygium Surgery.

Purpose. The study aims to compare the long-term outcome of conjunctival autograft (CAU) and mitomycin C (MMC) in double-head pterygium surgery. Methods. This is a follow-up study of a comparative interventional trial. Thirty-nine eyes of the 36 patients with double-head pterygium excision in the original study 12 years ago were recruited for clinical assessment. Seven out of the 36 patients were lost. In the original study, each eye with double-head pterygium was randomized to have pterygium excision with CAU on one "head" (temporal or nasal) and MMC on the other "head." All patients were invited for clinical assessment for conjunctival bed status and the presence of pterygium recurrence in the current study. Results. There was no significant difference between the size, morphology, and type of pterygium among the two treatment groups. The recurrence rate of CAU group and MMC group 12 years after excision was 6.3% and 28.1%, respectively (P = 0.020). Among eyes without recurrence, the conjunctival bed was graded higher in the MMC group than the CAU group (P = 0.024). Conclusion. The use of conjunctival autograft has a significantly lower long-term recurrence rate than mitomycin C in double-head pterygium surgery.

Corneal collagen cross-linking for infectious keratitis: an update of clinical studies.

Collagen cross-linking (CXL) with ultraviolet light-activated riboflavin is a corneal surface procedure developed for the treatment of keratoconus and corneal ectasia. With the known microbicidal and corneal stiffening effects of ultraviolet irradiation and photoactivated riboflavin, it has recently been introduced for the management of infectious keratitis, especially for ulcers resistant to antimicrobial therapy or associated with corneal melting. Various authors have attempted to use CXL as an adjunctive, salvage or even as the sole treatment for infectious corneal ulcers. The aim of this review was to provide a summary of the clinical studies in the literature. It is worth noting that there is still no consensus on the treatment protocol of CXL against infectious keratitis. The disparities in outcome measures, treatment protocol and study design can confound the interpretation and hamper the generalization of the study results. Based on current evidence, the role of CXL in infectious keratitis remained unclear despite the reported success in some clinical cases. Further investigations are warranted concerning the efficacy and safety of treating infectious keratitis with CXL.

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

PURPOSE: To investigate the central macular thickness (CMT) in myopic, emmetropic, and hyperopic Chinese children using Optical Coherence Tomography. METHODS: 168 right eyes of Chinese subjects aged 4-18 were divided into 3 groups based on their postcycloplegic spherical equivalent: myopes (<-1.0 D); emmetropes (≥-1.0 to ≤+1.0 D); and hyperopes (>+1.0 D) and the CMT was compared before/after age adjustment. The CMT was correlated with age, axial length, and peripapillary retinal nerve fibre layer (RNFL). RESULTS: The mean CMT was 274.9 ± 50.3 µm and the mean population age was 7.6 ± 3.3 years. The CMT was thickest in the myopes (283.3 ± 57.3 µm, n = 56), followed by the hyperopes (266.2 ± 55.31 µm, n = 60) and then emmetropes (259.8 ± 28.7 µm, n = 52) (all P < 0.0001). When adjusted for age, myopes had a thicker CMT than the other 2 groups (all P < 0.0001) but there was no CMT difference between the emmetropes and hyperopes (P > 0.05). There was no significant correlation between CMT with age, axial length, or peripapillary RNFL (all P ≥ 0.2). CONCLUSION: Chinese children with myopia had a thicker CMT than those with emmetropia or hyperopia. There was no correlation of the CMT with age, axial length, or peripapillary RNFL thickness.

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

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