Barbara Tam - Academia.edu (original) (raw)

Papers by Barbara Tam

Research paper thumbnail of Macular hole surgery with or without indocyanine green stained internal limiting membrane peeling

Clinical and Experimental Ophthalmology, 2004

To compare the anatomical and visual outcome in primary idiopathic macular hole surgery with or w... more To compare the anatomical and visual outcome in primary idiopathic macular hole surgery with or without indocyanine green (ICG) stained internal limiting membrane (ILM) peeling.

Research paper thumbnail of Prevalence and Characteristics of Peripheral Retinal Degeneration in Chinese Adults with High Myopia: A Cross-Sectional Prevalence Survey

Optometry and Vision Science, Apr 1, 2005

The purpose of this study was to study the prevalence of peripheral retinal findings in adult Chi... more The purpose of this study was to study the prevalence of peripheral retinal findings in adult Chinese patients with high myopia (refraction < or = -6.00 D) and to investigate the correlation between the retinal lesions and the severity of myopia or axial length. A cross-sectional prevalence survey screening was conducted in high ethnic Chinese myopes with refractions equal to or less than -6.00 D. The examinations included cycloplegic refraction, A and B scan ultrasonography, and retinal examinations by indirect ophthalmoscopy with scleral indentation and Goldmann three-mirror contact lens examination. Two hundred thirteen eyes in 213 patients with a mean refraction of -10.10 +/- 4.23 D (range = -6.00 to -27.00 D) were examined. The mean axial length was 26.69 +/- 1.68 mm (range = 25.18-33.62 mm) and the mean age was 33.5 +/- 10.6 years (range = 18-73 years). The most common peripheral retinal finding was pigmentary degeneration (51.2%), followed by lattice degeneration in 12.2% and retinal holes in 7.5% of eyes. A positive correlation was noted between axial length and the lesions of pigmentary degeneration and pavingstone degeneration. The prevalence of retinal holes was 6.4% and 30.0% in eyes with axial length of < 30 mm and > or = 30 mm, respectively (chi-squared test, p = 0.006). A high prevalence of peripheral retinal degenerations was found in adult Chinese high myopes. The presence of retinal holes was positively correlated with very high myopia of an axial length of > or = 30 mm.

Research paper thumbnail of Silicone oil tamponade for macular holes

Research paper thumbnail of Prevalence and Characteristics of Peripheral Retinal Degeneration in Chinese Adults with High Myopia: A Cross-Sectional Prevalence Survey

Optometry and Vision Science, 2005

The purpose of this study was to study the prevalence of peripheral retinal findings in adult Chi... more The purpose of this study was to study the prevalence of peripheral retinal findings in adult Chinese patients with high myopia (refraction < or = -6.00 D) and to investigate the correlation between the retinal lesions and the severity of myopia or axial length. A cross-sectional prevalence survey screening was conducted in high ethnic Chinese myopes with refractions equal to or less than -6.00 D. The examinations included cycloplegic refraction, A and B scan ultrasonography, and retinal examinations by indirect ophthalmoscopy with scleral indentation and Goldmann three-mirror contact lens examination. Two hundred thirteen eyes in 213 patients with a mean refraction of -10.10 +/- 4.23 D (range = -6.00 to -27.00 D) were examined. The mean axial length was 26.69 +/- 1.68 mm (range = 25.18-33.62 mm) and the mean age was 33.5 +/- 10.6 years (range = 18-73 years). The most common peripheral retinal finding was pigmentary degeneration (51.2%), followed by lattice degeneration in 12.2% and retinal holes in 7.5% of eyes. A positive correlation was noted between axial length and the lesions of pigmentary degeneration and pavingstone degeneration. The prevalence of retinal holes was 6.4% and 30.0% in eyes with axial length of < 30 mm and > or = 30 mm, respectively (chi-squared test, p = 0.006). A high prevalence of peripheral retinal degenerations was found in adult Chinese high myopes. The presence of retinal holes was positively correlated with very high myopia of an axial length of > or = 30 mm.

Research paper thumbnail of Topical Anesthesia in Posterior Vitrectomy

Retina, 2000

To evaluate the efficacy of topical anesthesia as an alternative to peribulbar or retrobulbar ane... more To evaluate the efficacy of topical anesthesia as an alternative to peribulbar or retrobulbar anesthesia in posterior vitrectomy procedures. Posterior vitrectomy using topical anesthesia (4% lidocaine drops) was performed prospectively in 134 eyes (134 patients) with various vitreoretinal diseases, including severe proliferative diabetic retinopathy (n = 69), vitreous hemorrhage (n = 12), rhegmatogenous retinal detachments (n = 11), epiretinal membranes (n = 10), macular holes (n = 7), dislocated crystalline lens or intraocular lens (n = 6), giant retinal tears (n = 5), intraocular foreign bodies (n = 3), trauma (n = 3), endophthalmitis (n = 3), subfoveal choroidal neovascular membrane (n = 3), and neovascular glaucoma (n = 2). In 26 (19.4%) eyes, posterior vitrectomy was combined with a scleral buckling procedure, and in 84 (62.6%) eyes, argon laser photocoagulation was performed. Preoperative and intraoperative sedation of varying degrees was necessary. Subjective pain and discomfort were graded from 1 (no pain or discomfort) to 4 (severe pain and discomfort). All patients had grade 1 pain and discomfort during most of the procedure. All patients had grade 2 (mild) pain and discomfort during pars plana sclerotomies, external bipolar cautery, and conjunctival closure. The average amount of 4% lidocaine drops needed during each procedure was 0.5 mL. No patient required additional retrobulbar, peribulbar, or sub-Tenon anesthesia. This technique avoids the risk of globe perforation, retrobulbar hemorrhage, and prolonged postoperative akinesia of the eye. With appropriate case selection, topical anesthesia is a safe and effective alternative to peribulbar or retrobulbar anesthesia in three-port pars plana vitrectomy procedures.

Research paper thumbnail of Early Pituitary-Adrenal Responses and Retinopathy of Prematurity in Very Low Birth Weight Infants

Pediatric Research, 2004

This longitudinal prospective study aimed to investigate the relationship between pituitary-adren... more This longitudinal prospective study aimed to investigate the relationship between pituitary-adrenal responses and severity of retinopathy of prematurity (ROP) in 92 preterm, very low birth weight infants < or = 30 wk gestation. The human corticotropin releasing hormone stimulation test was performed on these infants at D 7 and 14 of postnatal life. Univariate analysis revealed significant associations between severity of ROP and gestational age (r = -0.53, p < 0.0001), birth weight (r = -0.56, p < 0.0001), Apgar score at 1 min (r = -0.27, p < 0.05), Clinical Risk Index for Babies score (r = 0.48, p < 0.0001), duration of mechanical ventilation (r = 0.48, p < 0.0001), oxygen dependency (r = 0.48, p < 0.0001), and length of hospitalization (r = 0.49, p < 0.0001). The stage of ROP was also significantly associated with the basal and peak plasma ACTH (r > -0.22, p…

Research paper thumbnail of Transient Increase in Intraocular Pressure during a Dose-Tapering Regime of Systemic Dexamethasone in Preterm Infants

Ophthalmology, 2008

To determine the intraocular pressure (IOP) profile during and after systemic dexamethasone treat... more To determine the intraocular pressure (IOP) profile during and after systemic dexamethasone treatment in preterm very low birth weight (VLBW; Ͻ1500 g) infants.

Research paper thumbnail of Needle tap in the diagnosis of inflammation

Research paper thumbnail of Photodynamic therapy with verteporfin for subfoveal idiopathic choroidal neovascularization

Ophthalmology, 2003

The authors describe the management of subfoveal choroidal neovascular membranes in highly myopic... more The authors describe the management of subfoveal choroidal neovascular membranes in highly myopic eyes after laser in situ keratomileusis with photodynamic therapy. Five cases of choroidal neovascular membrane after laser in situ keratomileusis for the correction of myopia (mean, 13.3 diopters; range, -8.00 to -16.25 diopters) treated with single or multiple sessions of photodynamic therapy with verteporfin are presented. Two cases had improved visual acuity (2 to 5 lines) after photodynamic therapy, two cases remained the same, and one case lost 4 lines of visual acuity. Photodynamic therapy with verteporfin seems to increase the chance of stabilizing or improving vision in patients with subfoveal choroidal neovascular membrane after laser in situ keratomileusis in highly myopic eyes.

Research paper thumbnail of 25-Gauge Vitrectomy

Research paper thumbnail of Retinal breaks

Research paper thumbnail of Sutureless vitrectomy surgery

Research paper thumbnail of Combined cataract extraction and submacular blood clot evacuation for globe perforation caused by retrobulbar injection

Journal of Cataract & Refractive Surgery, 2000

A 45-year-old woman, originally scheduled for cataract surgery in the left eye, was referred for ... more A 45-year-old woman, originally scheduled for cataract surgery in the left eye, was referred for management of a globe perforation noticed after the retrobulbar injection of an anesthetic solution. There was a moderate degree of vitreous hemorrhage, and initial visual acuity was hand movement. A submacular blood clot of about 4-disc diameter was detected when the vitreous hemorrhage gradually cleared. One week after the incident, combined phacoemulsification, intraocular lens implantation, pars plana vitrectomy, and submacular clot removal using tissue plasminogen activator (tPA) as an adjunct were performed. Recovery was uneventful. At the last follow-up 6 months after surgery, best corrected visual acuity was 20/30.

Research paper thumbnail of A Longitudinal Study to Establish the Normative Value and to Evaluate Perinatal Factors Affecting Intraocular Pressure in Preterm Infants

Investigative Ophthalmology & Visual Science, 2008

To establish a normative range of intraocular pressure (IOP) in preterm infants and to identify i... more To establish a normative range of intraocular pressure (IOP) in preterm infants and to identify important perinatal factors that could affect the IOP during the early weeks of neonatal life. The IOP of 104 preterm infants, with a median (interquartile range) gestational age of 29.8 (28.7-30.9) weeks and birth weight of 1208 (1049-1370) g, were assessed in a university-affiliated tertiary neonatal center. These infants had IOP measured by a handheld tonometer at 1, 4, 6, 8, and 10 weeks of postnatal age. The mixed-effects models were used to evaluate the longitudinal IOP measurements and to identify critical perinatal factors that would significantly affect the ocular pressure. A percentile chart of IOP in preterm infants was constructed, and the median (10th-90th percentile) IOP ranged from 16.9 (12.3-21.5) to 14.6 (10.1-19.2) mm Hg at 26.1 and 46.4 weeks of postconceptional age, respectively. The IOP was significantly and negatively associated with postconceptional age (P < 0.001), mean blood pressure (P = 0.01), Apgar score at 1 minute (P = 0.04), and use of inhaled corticosteroids (P = 0.03), but was positively correlated with the commencement of high-frequency oscillatory ventilation (P = 0.01). A quantitative statistical model has been developed and a percentile chart of IOP constructed for preterm infants that could be used for future reference. Pediatric ophthalmologists and neonatal clinicians can compare the IOP of preterm infants against this chart and make relevant quantitative adjustments for critical perinatal factors so that the IOP may be properly evaluated, both in healthy and ill infants.

Research paper thumbnail of Precautions in ophthalmic practice in a hospital with a major acute SARS outbreak: an experience from Hong Kong

Eye, 2006

Many new infectious diseases in humans have been derived from animal sources in the past 20 years... more Many new infectious diseases in humans have been derived from animal sources in the past 20 years. Some are highly contagious and fatal. Vaccination may not be available and antiviral drugs are not effective enough. Infectious control is important in clinical medicine and in Ophthalmology. Severe acute respiratory syndrome (SARS), as an example, is a highly contagious respiratory disease that has recently been reported in Asia, North America, and Europe. Within a matter of weeks, the outbreak has evolved to become a global health threat and more than 30 countries have been afflicted with a novel Coronavirus strain (SARS-CoV) that is the aetiologic agent of SARS. The primary route of transmission of SARS appears involving close person-toperson contact through droplets. Ophthalmologists may be particularly susceptible to the infection as routine ophthalmic examinations like direct ophthalmoscopy and slit-lamp examination are usually performed in a setting that has close doctor-patient contact. Being the Ophthalmology Department of the only hospital in the world that has just gone through the largest outbreak of SARS, we would like to share our strategy, measures, and experiences of preventing contracting or spreading of SARS infection as an infection control model. SARS is one of the many viruses against which personnel will need protecting in an ophthalmic setting. The experiences attained and the measures established might also apply to other infectious conditions spreading by droplets such as the avian influenza with H5N1.

Research paper thumbnail of Para-lenticular metallic foreign body missed by high- resolution computed tomography

Research paper thumbnail of Spontaneous reattachment of retinal detachment in a highly myopic eye with a macular hole

Eye, 2000

therefore, when given at a dose of 65 mg/kg (in children less than 20 kg) or 130 mg (in children ... more therefore, when given at a dose of 65 mg/kg (in children less than 20 kg) or 130 mg (in children more than 20 kg), has been shown to cause a small but significant improvement in visual acuity as demonstrated by visual evoked potentials. However, long-term results are awaited.

Research paper thumbnail of Macular hole surgery with or without indocyanine green stained internal limiting membrane peeling

Clinical and Experimental Ophthalmology, 2003

To compare the anatomical and visual outcome in primary idiopathic macular hole surgery with or w... more To compare the anatomical and visual outcome in primary idiopathic macular hole surgery with or without indocyanine green (ICG) stained internal limiting membrane (ILM) peeling.

Research paper thumbnail of Macular Hole Surgery Using Thrombin-Activated Fibrinogen and Selective Removal of the Internal Limiting Membrane

Retina, 1999

To evaluate a tissue sealant (autologous cryoprecipitate activated with bovine thrombin) as an ad... more To evaluate a tissue sealant (autologous cryoprecipitate activated with bovine thrombin) as an adjuvant in macular hole surgery. Sixty-nine patients with stage 2, 3, or 4 full-thickness macular hole were enrolled consecutively in a prospective pilot study. Anatomic closure of the macular holes with a single operation was the primary outcome. Fifty-eight patients had pre- and postoperative standardized measurements including best refracted visual acuity, reading speed, and contrast sensitivity. Group A patients (45) had primary macular holes; Group B patients (13) had recurrent macular holes or macular holes with "other" retinal pathology. Surgical technique was standardized and membrane dissections were optional. The anatomic closure rate was 80% with a minimum of 6 months follow-up. Mean improvement in visual acuity for Group A (2.9+/-0.4 lines) was significantly better than for Group B (0.8+/-0.5 lines; P = 0.008). Eyes that underwent internal limiting membrane (ILM) dissections had an anatomic closure rate of 96% (23/24), compared with 71% (32/45) in "non-ILM" cases (P = 0.034). Adverse reactions included sterile hypopyon (10%), intraretinal hemorrhage (9%), pigmentary hyperplasia (3%), and retinal detachment (3%). Tissue sealants should be evaluated as an adjuvant in macular hole surgery in a randomized clinical trial. Inflammatory reactions may occur in some patients. Internal limiting membrane dissection may improve anatomic closure rates without adversely affecting the visual acuity.

Research paper thumbnail of Macular hole surgery with or without indocyanine green stained internal limiting membrane peeling

Clinical and Experimental Ophthalmology, 2004

To compare the anatomical and visual outcome in primary idiopathic macular hole surgery with or w... more To compare the anatomical and visual outcome in primary idiopathic macular hole surgery with or without indocyanine green (ICG) stained internal limiting membrane (ILM) peeling.

Research paper thumbnail of Prevalence and Characteristics of Peripheral Retinal Degeneration in Chinese Adults with High Myopia: A Cross-Sectional Prevalence Survey

Optometry and Vision Science, Apr 1, 2005

The purpose of this study was to study the prevalence of peripheral retinal findings in adult Chi... more The purpose of this study was to study the prevalence of peripheral retinal findings in adult Chinese patients with high myopia (refraction < or = -6.00 D) and to investigate the correlation between the retinal lesions and the severity of myopia or axial length. A cross-sectional prevalence survey screening was conducted in high ethnic Chinese myopes with refractions equal to or less than -6.00 D. The examinations included cycloplegic refraction, A and B scan ultrasonography, and retinal examinations by indirect ophthalmoscopy with scleral indentation and Goldmann three-mirror contact lens examination. Two hundred thirteen eyes in 213 patients with a mean refraction of -10.10 +/- 4.23 D (range = -6.00 to -27.00 D) were examined. The mean axial length was 26.69 +/- 1.68 mm (range = 25.18-33.62 mm) and the mean age was 33.5 +/- 10.6 years (range = 18-73 years). The most common peripheral retinal finding was pigmentary degeneration (51.2%), followed by lattice degeneration in 12.2% and retinal holes in 7.5% of eyes. A positive correlation was noted between axial length and the lesions of pigmentary degeneration and pavingstone degeneration. The prevalence of retinal holes was 6.4% and 30.0% in eyes with axial length of < 30 mm and > or = 30 mm, respectively (chi-squared test, p = 0.006). A high prevalence of peripheral retinal degenerations was found in adult Chinese high myopes. The presence of retinal holes was positively correlated with very high myopia of an axial length of > or = 30 mm.

Research paper thumbnail of Silicone oil tamponade for macular holes

Research paper thumbnail of Prevalence and Characteristics of Peripheral Retinal Degeneration in Chinese Adults with High Myopia: A Cross-Sectional Prevalence Survey

Optometry and Vision Science, 2005

The purpose of this study was to study the prevalence of peripheral retinal findings in adult Chi... more The purpose of this study was to study the prevalence of peripheral retinal findings in adult Chinese patients with high myopia (refraction < or = -6.00 D) and to investigate the correlation between the retinal lesions and the severity of myopia or axial length. A cross-sectional prevalence survey screening was conducted in high ethnic Chinese myopes with refractions equal to or less than -6.00 D. The examinations included cycloplegic refraction, A and B scan ultrasonography, and retinal examinations by indirect ophthalmoscopy with scleral indentation and Goldmann three-mirror contact lens examination. Two hundred thirteen eyes in 213 patients with a mean refraction of -10.10 +/- 4.23 D (range = -6.00 to -27.00 D) were examined. The mean axial length was 26.69 +/- 1.68 mm (range = 25.18-33.62 mm) and the mean age was 33.5 +/- 10.6 years (range = 18-73 years). The most common peripheral retinal finding was pigmentary degeneration (51.2%), followed by lattice degeneration in 12.2% and retinal holes in 7.5% of eyes. A positive correlation was noted between axial length and the lesions of pigmentary degeneration and pavingstone degeneration. The prevalence of retinal holes was 6.4% and 30.0% in eyes with axial length of < 30 mm and > or = 30 mm, respectively (chi-squared test, p = 0.006). A high prevalence of peripheral retinal degenerations was found in adult Chinese high myopes. The presence of retinal holes was positively correlated with very high myopia of an axial length of > or = 30 mm.

Research paper thumbnail of Topical Anesthesia in Posterior Vitrectomy

Retina, 2000

To evaluate the efficacy of topical anesthesia as an alternative to peribulbar or retrobulbar ane... more To evaluate the efficacy of topical anesthesia as an alternative to peribulbar or retrobulbar anesthesia in posterior vitrectomy procedures. Posterior vitrectomy using topical anesthesia (4% lidocaine drops) was performed prospectively in 134 eyes (134 patients) with various vitreoretinal diseases, including severe proliferative diabetic retinopathy (n = 69), vitreous hemorrhage (n = 12), rhegmatogenous retinal detachments (n = 11), epiretinal membranes (n = 10), macular holes (n = 7), dislocated crystalline lens or intraocular lens (n = 6), giant retinal tears (n = 5), intraocular foreign bodies (n = 3), trauma (n = 3), endophthalmitis (n = 3), subfoveal choroidal neovascular membrane (n = 3), and neovascular glaucoma (n = 2). In 26 (19.4%) eyes, posterior vitrectomy was combined with a scleral buckling procedure, and in 84 (62.6%) eyes, argon laser photocoagulation was performed. Preoperative and intraoperative sedation of varying degrees was necessary. Subjective pain and discomfort were graded from 1 (no pain or discomfort) to 4 (severe pain and discomfort). All patients had grade 1 pain and discomfort during most of the procedure. All patients had grade 2 (mild) pain and discomfort during pars plana sclerotomies, external bipolar cautery, and conjunctival closure. The average amount of 4% lidocaine drops needed during each procedure was 0.5 mL. No patient required additional retrobulbar, peribulbar, or sub-Tenon anesthesia. This technique avoids the risk of globe perforation, retrobulbar hemorrhage, and prolonged postoperative akinesia of the eye. With appropriate case selection, topical anesthesia is a safe and effective alternative to peribulbar or retrobulbar anesthesia in three-port pars plana vitrectomy procedures.

Research paper thumbnail of Early Pituitary-Adrenal Responses and Retinopathy of Prematurity in Very Low Birth Weight Infants

Pediatric Research, 2004

This longitudinal prospective study aimed to investigate the relationship between pituitary-adren... more This longitudinal prospective study aimed to investigate the relationship between pituitary-adrenal responses and severity of retinopathy of prematurity (ROP) in 92 preterm, very low birth weight infants < or = 30 wk gestation. The human corticotropin releasing hormone stimulation test was performed on these infants at D 7 and 14 of postnatal life. Univariate analysis revealed significant associations between severity of ROP and gestational age (r = -0.53, p < 0.0001), birth weight (r = -0.56, p < 0.0001), Apgar score at 1 min (r = -0.27, p < 0.05), Clinical Risk Index for Babies score (r = 0.48, p < 0.0001), duration of mechanical ventilation (r = 0.48, p < 0.0001), oxygen dependency (r = 0.48, p < 0.0001), and length of hospitalization (r = 0.49, p < 0.0001). The stage of ROP was also significantly associated with the basal and peak plasma ACTH (r > -0.22, p…

Research paper thumbnail of Transient Increase in Intraocular Pressure during a Dose-Tapering Regime of Systemic Dexamethasone in Preterm Infants

Ophthalmology, 2008

To determine the intraocular pressure (IOP) profile during and after systemic dexamethasone treat... more To determine the intraocular pressure (IOP) profile during and after systemic dexamethasone treatment in preterm very low birth weight (VLBW; Ͻ1500 g) infants.

Research paper thumbnail of Needle tap in the diagnosis of inflammation

Research paper thumbnail of Photodynamic therapy with verteporfin for subfoveal idiopathic choroidal neovascularization

Ophthalmology, 2003

The authors describe the management of subfoveal choroidal neovascular membranes in highly myopic... more The authors describe the management of subfoveal choroidal neovascular membranes in highly myopic eyes after laser in situ keratomileusis with photodynamic therapy. Five cases of choroidal neovascular membrane after laser in situ keratomileusis for the correction of myopia (mean, 13.3 diopters; range, -8.00 to -16.25 diopters) treated with single or multiple sessions of photodynamic therapy with verteporfin are presented. Two cases had improved visual acuity (2 to 5 lines) after photodynamic therapy, two cases remained the same, and one case lost 4 lines of visual acuity. Photodynamic therapy with verteporfin seems to increase the chance of stabilizing or improving vision in patients with subfoveal choroidal neovascular membrane after laser in situ keratomileusis in highly myopic eyes.

Research paper thumbnail of 25-Gauge Vitrectomy

Research paper thumbnail of Retinal breaks

Research paper thumbnail of Sutureless vitrectomy surgery

Research paper thumbnail of Combined cataract extraction and submacular blood clot evacuation for globe perforation caused by retrobulbar injection

Journal of Cataract & Refractive Surgery, 2000

A 45-year-old woman, originally scheduled for cataract surgery in the left eye, was referred for ... more A 45-year-old woman, originally scheduled for cataract surgery in the left eye, was referred for management of a globe perforation noticed after the retrobulbar injection of an anesthetic solution. There was a moderate degree of vitreous hemorrhage, and initial visual acuity was hand movement. A submacular blood clot of about 4-disc diameter was detected when the vitreous hemorrhage gradually cleared. One week after the incident, combined phacoemulsification, intraocular lens implantation, pars plana vitrectomy, and submacular clot removal using tissue plasminogen activator (tPA) as an adjunct were performed. Recovery was uneventful. At the last follow-up 6 months after surgery, best corrected visual acuity was 20/30.

Research paper thumbnail of A Longitudinal Study to Establish the Normative Value and to Evaluate Perinatal Factors Affecting Intraocular Pressure in Preterm Infants

Investigative Ophthalmology & Visual Science, 2008

To establish a normative range of intraocular pressure (IOP) in preterm infants and to identify i... more To establish a normative range of intraocular pressure (IOP) in preterm infants and to identify important perinatal factors that could affect the IOP during the early weeks of neonatal life. The IOP of 104 preterm infants, with a median (interquartile range) gestational age of 29.8 (28.7-30.9) weeks and birth weight of 1208 (1049-1370) g, were assessed in a university-affiliated tertiary neonatal center. These infants had IOP measured by a handheld tonometer at 1, 4, 6, 8, and 10 weeks of postnatal age. The mixed-effects models were used to evaluate the longitudinal IOP measurements and to identify critical perinatal factors that would significantly affect the ocular pressure. A percentile chart of IOP in preterm infants was constructed, and the median (10th-90th percentile) IOP ranged from 16.9 (12.3-21.5) to 14.6 (10.1-19.2) mm Hg at 26.1 and 46.4 weeks of postconceptional age, respectively. The IOP was significantly and negatively associated with postconceptional age (P < 0.001), mean blood pressure (P = 0.01), Apgar score at 1 minute (P = 0.04), and use of inhaled corticosteroids (P = 0.03), but was positively correlated with the commencement of high-frequency oscillatory ventilation (P = 0.01). A quantitative statistical model has been developed and a percentile chart of IOP constructed for preterm infants that could be used for future reference. Pediatric ophthalmologists and neonatal clinicians can compare the IOP of preterm infants against this chart and make relevant quantitative adjustments for critical perinatal factors so that the IOP may be properly evaluated, both in healthy and ill infants.

Research paper thumbnail of Precautions in ophthalmic practice in a hospital with a major acute SARS outbreak: an experience from Hong Kong

Eye, 2006

Many new infectious diseases in humans have been derived from animal sources in the past 20 years... more Many new infectious diseases in humans have been derived from animal sources in the past 20 years. Some are highly contagious and fatal. Vaccination may not be available and antiviral drugs are not effective enough. Infectious control is important in clinical medicine and in Ophthalmology. Severe acute respiratory syndrome (SARS), as an example, is a highly contagious respiratory disease that has recently been reported in Asia, North America, and Europe. Within a matter of weeks, the outbreak has evolved to become a global health threat and more than 30 countries have been afflicted with a novel Coronavirus strain (SARS-CoV) that is the aetiologic agent of SARS. The primary route of transmission of SARS appears involving close person-toperson contact through droplets. Ophthalmologists may be particularly susceptible to the infection as routine ophthalmic examinations like direct ophthalmoscopy and slit-lamp examination are usually performed in a setting that has close doctor-patient contact. Being the Ophthalmology Department of the only hospital in the world that has just gone through the largest outbreak of SARS, we would like to share our strategy, measures, and experiences of preventing contracting or spreading of SARS infection as an infection control model. SARS is one of the many viruses against which personnel will need protecting in an ophthalmic setting. The experiences attained and the measures established might also apply to other infectious conditions spreading by droplets such as the avian influenza with H5N1.

Research paper thumbnail of Para-lenticular metallic foreign body missed by high- resolution computed tomography

Research paper thumbnail of Spontaneous reattachment of retinal detachment in a highly myopic eye with a macular hole

Eye, 2000

therefore, when given at a dose of 65 mg/kg (in children less than 20 kg) or 130 mg (in children ... more therefore, when given at a dose of 65 mg/kg (in children less than 20 kg) or 130 mg (in children more than 20 kg), has been shown to cause a small but significant improvement in visual acuity as demonstrated by visual evoked potentials. However, long-term results are awaited.

Research paper thumbnail of Macular hole surgery with or without indocyanine green stained internal limiting membrane peeling

Clinical and Experimental Ophthalmology, 2003

To compare the anatomical and visual outcome in primary idiopathic macular hole surgery with or w... more To compare the anatomical and visual outcome in primary idiopathic macular hole surgery with or without indocyanine green (ICG) stained internal limiting membrane (ILM) peeling.

Research paper thumbnail of Macular Hole Surgery Using Thrombin-Activated Fibrinogen and Selective Removal of the Internal Limiting Membrane

Retina, 1999

To evaluate a tissue sealant (autologous cryoprecipitate activated with bovine thrombin) as an ad... more To evaluate a tissue sealant (autologous cryoprecipitate activated with bovine thrombin) as an adjuvant in macular hole surgery. Sixty-nine patients with stage 2, 3, or 4 full-thickness macular hole were enrolled consecutively in a prospective pilot study. Anatomic closure of the macular holes with a single operation was the primary outcome. Fifty-eight patients had pre- and postoperative standardized measurements including best refracted visual acuity, reading speed, and contrast sensitivity. Group A patients (45) had primary macular holes; Group B patients (13) had recurrent macular holes or macular holes with "other" retinal pathology. Surgical technique was standardized and membrane dissections were optional. The anatomic closure rate was 80% with a minimum of 6 months follow-up. Mean improvement in visual acuity for Group A (2.9+/-0.4 lines) was significantly better than for Group B (0.8+/-0.5 lines; P = 0.008). Eyes that underwent internal limiting membrane (ILM) dissections had an anatomic closure rate of 96% (23/24), compared with 71% (32/45) in "non-ILM" cases (P = 0.034). Adverse reactions included sterile hypopyon (10%), intraretinal hemorrhage (9%), pigmentary hyperplasia (3%), and retinal detachment (3%). Tissue sealants should be evaluated as an adjuvant in macular hole surgery in a randomized clinical trial. Inflammatory reactions may occur in some patients. Internal limiting membrane dissection may improve anatomic closure rates without adversely affecting the visual acuity.