Ethnic variation in medial orbital wall anatomy and its implications for decompression surgery.

BACKGROUND: To describe the inter-ethnic variation in medial orbital wall anatomy between Chinese, Malay, Indian and Caucasian subjects. METHODS: Single-centre, retrospective, Computed Tomography (CT)-based observational study. 20 subjects of each ethnicity, were matched for gender and laterality. We excluded subjects younger than 16 years and those with orbital pathology. OsiriX version 8.5.1 (Pixmeo., Switzerland) and DICOM image viewing software CARESTREAM Vue PACS (Carestream Health Inc., USA) were used to measure the ethmoidal sinus length, width and volume, medial orbital wall and floor angle and the relative position of the posterior ethmoid sinus to the posterior maxillary wall. Statistical analyses were performed using Statistical Package for Social Sciences version 25.0 (IBM, USA). RESULTS: There were 12 males (60 %) in each group, with no significant difference in age (p = 0.334-0.994). The mean ethmoid sinus length in Chinese, Malay, Indian and Caucasian subjects, using the Chinese as reference, were 37.2, 36.9, 38.0 and 37.4mm, the mean width was 11.6, 10.5, 11.4 and 10.0mm (p = 0.020) and the mean ethmoid sinus volume were 3362, 3652, 3349 and 3898mm3 respectively. The mean medial orbital wall and floor angle was 135.0, 131.4, 131.0 and 136.8 degrees and the mean relative position of posterior ethmoid sinus to posterior maxillary wall were - 2.0, -0.2, -1.5 and 1.6mm (p = 0.003) respectively. CONCLUSIONS: No inter-ethnic variation was found in decompressible ethmoid sinus volume. Caucasians had their posterior maxillary sinus wall anterior to their posterior ethmoidal walls unlike the Chinese, Malay and Indians. Awareness of ethnic variation is essential for safe orbital decompression.

Urea-De-Epithelialized Human Amniotic Membrane for Ocular Surface Reconstruction.

The conjunctiva is a clear tissue covering the white part of the eye and lines the back of the eyelids. Conjunctival diseases, such as symblepharon, cause inflammation, discharges, and photophobia. The treatment often requires excision of large parts of conjunctiva. Tissue engineering of conjunctival cells using human amniotic membrane (HAM) denuded of its epithelium as a basement membrane scaffold has been shown to be effective for covering conjunctival defects. However, most epithelial denudation protocols are time-consuming and expensive or compromise HAM's basement membrane structure and matrix components. We have previously described a method to de-epithelialize HAM using ice-cold urea (uHAM). In this report, we used this method to provide tissue-engineered constructs with cultivated conjunctival epithelial cells on uHAM in two patients, one with a giant conjunctival nevus and the other with a large symblepharon. Autologous conjunctival epithelial cells harvested from incisional biopsies of these two patients were cultured on the uHAM scaffold. The transplantation of tissue-engineered constructs to patients' ocular surface immediately after the removal of lesions showed successful reconstruction of the ocular surface. Postoperatively, there were neither recurrence of lesions nor epithelial defects throughout the follow-up (up to 7 and 19 months, respectively). This report highlights the translational potential of an efficient and inexpensive method to prepare de-epithelialized HAM as a basement membrane scaffold for cell-based tissue-engineered treatments of ocular surface disorders. Stem Cells Translational Medicine 2019;8:620&626.

Methotrexate as an Adjuvant in Severe Thyroid Eye Disease: Does It Really Work as a Steroid-Sparing Agent?

PURPOSE: To compare the efficacy and safety of adjunctive oral methotrexate with intravenous pulsed methylprednisolone against methylprednisolone alone in the treatment of severe thyroid eye disease. METHODS: Retrospective review of clinical data of patients with severe sight-threatening thyroid eye disease with compressive optic neuropathy treated with methylprednisolone with and without methotrexate. Eye disease outcome measures (e.g., VISA inflammatory score and vision) at 0, 3, 6, 12, and 18 months were recorded. RESULTS: There were 72 subjects including 33 who had methylprednisolone alone and 39 with methylprednisolone with methotrexate. There were no statistical differences in demographics and baseline measures of disease activity or vision between the 2 treatment groups. No significant statistical differences in the cumulative dosage of methylprednisolone or occurrence of restrictive myopathy, raised intraocular pressure, proptosis, and exposure keratopathy between the groups at 0, 3, 6, 12, and 18 months were found. However, subjects who received methylprednisolone with methotrexate had better visual acuity of more than 2 lines on Snellen chart (p = 0.026) and VISA inflammatory score (p = 0.034) at 3 months, but no differences at 6, 12, and 18 months. Three patients who received methylprednisolone with methotrexate had transient worsening of liver function. No patient developed severe adverse reaction. CONCLUSIONS: The results demonstrated improved vision and disease activity at 3 months in the combination treatment group. This may suggest that the addition of methotrexate to methylprednisolone is beneficial for accelerating suppression of disease activity and hastens visual recovery. Addition of methotrexate to methylprednisolone did not reduce the requirement for steroids.

Tear Proteins Calcium binding protein A4 (S100A4) and Prolactin Induced Protein (PIP) are Potential Biomarkers for Thyroid Eye Disease.

There are no reliable biomarkers to predict thyroid eye disease (TED) in patients with autoimmune thyroid disease (AITD) currently. Several evidences support the involvement of the lacrimal gland in TED. The aim of our study was to quantitatively correlate the changes in tear protein profile with increasing severity of TED. Tear samples were collected from four groups of patients; AITD without TED (AITD), AITD with mild TED (mild TED), AITD with severe TED (severe TED) and normal controls. A total of 72 patients were recruited for the study. In discovery phase, isobaric tags for relative and absolute quantification (iTRAQ) 4-plex was used for quantitative proteomics analysis. For verification of results from discovery phase, sequential window acquisition of all theoretical fragment ion spectra (SWATH) was used to analyze an independent cohort from normal controls, AITD, mild TED and severe TED. Two proteins, S100A4 and PIP showed consistent dysregulation trends in the discovery and validation phase experiments. Our study demonstrated the differences in tear proteome across the spectrum of different severity and activity of TED in patients with AITD. Two tear proteins, S100A4 and PIP may serve as potential biomarkers to predict progression to severe TED in patients with AITD.

Serum IgG2 and tissue IgG2 plasma cell elevation in orbital IgG4-related disease (IgG4-RD): Potential use in IgG4-RD assessment.

AIMS: To determine the role of serum and tissue IgG2 in orbital biopsies with the histological features of IgG4-related disease (IgG4-RD) in comparison with non-IgG4-related orbital inflammatory disorders (OID), including autoimmune disorders. METHODS: This is an international (Sheffield, UK, and Singapore) collaborative, retrospective case review of 69 patients (38 from Singapore National Eye Centre and 31 from Royal Hallamshire Hospital, Sheffield) with orbital inflammatory biopsies between 2002 and 2016. Clinical information and histology were reviewed and cases were classified into three groups: Group 1: IgG4-RD orbital inflammation (n=43); Group 2: idiopathic OID (n=12) and Group 3: autoimmune OID (n=14). Serum IgG1, IgG2, IgG3 and IgG4 levels were collated where available and immunohistochemistry (IHC) for tissue IgG2 plasma cells was performed. RESULTS: Dual IHC showed IgG2 plasma cells as a distinct population from IgG4 plasma cells. Significant (twofold) serum IgG2 elevation was noted among IgG4-RD (group 1), idiopathic (group 2) and autoimmune OID (group 3). Similarly, significant elevation of tissue IgG2 plasma cells was also seen among IgG4-RD (group 1), idiopathic and autoimmune OID (groups 2 and 3). CONCLUSIONS: Significant elevations of serum IgG2 and tissue IgG2 plasma cells are present in orbital IgG4-RD in comparison with non-IgG4 orbital inflammation (idiopathic and autoimmune OID), suggesting that IgG2 may play a role in IgG4-RD. A serum IgG2 cut-off >5.3 g/L was found to be 80% sensitive and 91.7% specific for orbital IgG4-RD, with an accuracy of 0.90. Tissue IgG2 and IgG4 subclass reporting may provide additional insight regarding the 'IgG4-RD' pathogenesis.

Clinical Features and Treatment Outcomes of Orbital Inflammatory Disease in Singapore: A 10-Year Clinicopathologic Review.

PURPOSE: 1) To assess the clinical profile and treatment outcomes of orbital inflammatory disease in the local population, and 2) classify patients using current histopathological criteria. METHODS: Ten-year retrospective clinicopathologic review of patients diagnosed with orbital inflammatory disease who underwent tissue biopsy from January 2001 to December 2011 at a tertiary referral centre in Singapore. Data collection included patient demographics, clinical presentation, investigations, systemic disease, histopathology review, clinical classification, medical and surgical management, response to treatment and recurrence rates. RESULTS: The study comprised 70 patients. Thirty-seven (52.9%) had nonspecific inflammation distributed as follows: lacrimal (n = 23), diffuse (n = 5), anterior (n = 5), myositic (n = 4). Thirty-three (47.1%) had specific inflammation of the following subtypes: idiopathic sclerosing inflammation (n = 9), granulomatous disorders (n = 8), transitional lesions (n = 5), vasculitis (n = 4), and others (n = 7). A total of 76.8% of patients received oral prednisolone, with a median duration of three months. Response to treatment was good in 71.9% of patients. Recurrence occurred in 22 (32.8%) patients at a mean interval of 20 months after completion of treatment, and was higher in myositic and vasculitic subtypes. There was no significant correlation between duration of treatment and recurrence. CONCLUSIONS: This study has re-emphasized the importance and utility of orbital biopsy and histopathologic typing for optimal management of orbital inflammatory disease. It has also improved the knowledge of the rate and response to treatment of its various subtypes.

Axial Globe Position Measurement: A Prospective Multicenter Study by the International Thyroid Eye Disease Society.

PURPOSE: Identify a reproducible measure of axial globe position (AGP) for multicenter studies on patients with thyroid eye disease (TED). METHODS: This is a prospective, international, multicenter, observational study in which 3 types of AGP evaluation were examined: radiologic, clinical, and photographic. In this study, CT was the modality to which all other methods were compared. CT AGP was measured from an orthogonal line between the anterior lateral orbital rims to the cornea. All CT measurements were made at a single institution by 3 individual clinicians. Clinical evaluation was performed with exophthalmometry. Three clinicians from each clinical site assessed AGP with 3 different exophthalmometers and horizontal palpebral width using a ruler. Each physician made 3 separate measurements with each type of exophthalmometer not in succession. All photographic measurements were made at a single institution. AGP was measured from lateral photographs in which a standard marker was placed at the anterior lateral orbital rim. Horizontal and vertical palpebral fissure were measured from frontal photographs. Three trained readers measured 3 separate times not in succession. Exophthalmometry and photography method validity was assessed by agreement with CT (mean differences calculation, intraclass correlation coefficients [ICCs], Bland-Altman figures). Correlation between palpebral fissure and CT AGP was assessed with Pearson correlation. Intraclinician and interclinician reliability was evaluated using ICCs. RESULTS: Sixty-eight patients from 7 centers participated. CT mean AGP was 21.37 mm (15.96-28.90 mm) right and 21.22 mm (15.87-28.70 mm) left (ICC 0.996 and 0.995). Exophthalmometry AGP fell between 18 mm and 25 mm. Intraclinician agreement across exophthalmometers was ideal (ICC 0.948-0.983). Agreement between clinicians was greater than 0.85 for all upright exophthalmometry measurements. Photographic mean AGP was 20.47 mm (10.92-30.88 mm) right and 20.30 mm (8.61-28.72 mm) left. Intrareader and interreader agreement was ideal (ICC 0.991-0.989). All exophthalmometers' mean differences from CT ranged between -0.06 mm (±1.36 mm) and 0.54 mm (±1.61 mm); 95% confidence interval fell within 1 mm. Magnitude of AGP did not affect exophthalmometry validity. Oculus best estimated CT AGP but differences from other exophthalmometers were not clinically meaningful in upright measurements. Photographic AGP (right ICC = 0.575, left ICC = 0.355) and palpebral fissure do not agree with CT. CONCLUSIONS: Upright clinical exophthalmometry accurately estimates CT AGP in TED. AGP measurement was reliably reproduced by the same clinician and between clinicians at multiple institutions using the protocol in this study. These findings allow reliable measurement of AGP that will be of considerable value in future outcome studies.

Prospective audit of ptosis surgery at the Singapore National Eye Centre: two-year results.

PURPOSE: To evaluate the demographics, presentation, and surgical outcomes of patients undergoing ptosis surgery in an Asian population in a prospective manner. METHODS: A prospective ptosis audit was conducted over a 2-year period from January 2010 to December 2011 in a tertiary eye hospital in Singapore. All patients undergoing ptosis surgery by, or under the supervision of, an oculoplastic-trained consultant in the institution were included. Institutional Review Board approval was obtained for the study. RESULTS: This study comprises 302 patients, of which 236 were acquired and 66 were congenital ptosis cases. Levator repair (77.2%) was the most commonly performed procedure, followed by levator resection (13.9%) and brow suspension (8.9%). Forty-seven (10.1%) eyes had readjustment within 2 weeks, the reasons for readjustment being eyelid height undercorrection (n = 35), eyelid height overcorrection (n = 9), and unsatisfactory eyelid contour (n = 4). Postoperatively, 93.8% of patients showed an increase in marginal reflex distance-1 (MRD1), 91.3% achieved symmetry or <1 mm of asymmetry in MRD1, 98.5% had good eyelid contour, and 74.3% had symmetric eyelid crease. On a scale of 1 to 10, 83.1% of patients gave a subjective grade of 7 or better. CONCLUSIONS: This study is the first prospective ptosis surgery audit in an Asian population and takes a leading step in assessing both subjective and objective surgical outcomes in a prospective manner. With the continuation of this audit in years to come, it will allow us to generate clinical outcomes in a robust manner and allow for more reliable benchmarking with major centers elsewhere.

B-cell targeted therapy with rituximab for thyroid eye disease: closer to the clinic.

The management of thyroid eye disease (TED) remains a therapeutic challenge. The current established therapies are unsatisfactory in one-third of the patients and have many limitations. Rituximab (RTX) is a CD20+ B-cell-depleting monoclonal antibody approved for the treatment of non-Hodgkin lymphomas, chronic lymphocytic leukemia, and rheumatoid arthritis. The early experience with RTX suggests that it is a promising alternative therapy for TED. Rituximab may compare favorably to the conventional glucocorticoid therapy and causes less collateral damage than retrobulbar orbital radiation and decompression surgery. In addition, the preliminary studies on RTX's proposed mechanism of action have revealed new insights into the pathogenic role of B-cells in TED. We summarize the current literature on the clinical application of RTX in TED and discuss its putative mechanisms of action.

A cadaveric study of the morphometric relationships and bony composition of the caucasian nasolacrimal fossa.

AIMS: To describe the morphometric relationships and bony composition of the nasolacrimal fossa in a Caucasian population with particular reference to the lacrimo-maxillary suture (LMS). METHODS: Forty-seven orbits from 24 formalin fixed cadavers were exenterated. Morphometric measurements were taken between anatomical landmarks forming the lacrimal fossa on the medial orbital wall. RESULTS: The mean recorded distance from the anterior lacrimal crest (ALC) to the posterior lacrimal crest (PLC) and the LMS were 8.8 mm (± 1.6) and 4.3 mm (± 1.1), respectively. In 25.5% of the orbits the LMS was at the mid-vertical line (MVL), defined as a line equidistant from the ALC and PLC. In 42.5% the LMS was located anterior to the MVL toward the ALC. In 66% of the orbits the LMS was at or within one standard deviation (SD) of the MVL. The LMS was >1 SD away from the MVL toward the ALC and PLC in 19% and 15% of orbits, respectively. CONCLUSIONS: In a quarter of the orbits in our Caucasian population the nasolacrimal fossa was formed equally by the maxillary and lacrimal bones. However, in nearly a third of the cases the LMS was located closer to the PLC, indicating predominance of the thicker maxillary bone. This may result in greater difficulty in initiating the surgical osteotomy when performing a dacryocystorhinostomy. These data contribute to our understanding of the variation in lacrimal fossa anatomy and encourage further studies in different racial groups.

A cadaveric study of the cranio-orbital foramen and its significance in orbital surgery.

BACKGROUND: The cranio-orbital foramen is an osseous anatomical landmark located adjacent to the superior orbital fissure. It is a potential source of hemorrhage during deep orbital dissection because it is the location of an anastomosis between the lacrimal artery and the middle meningeal artery. The purpose of this study was to determine the incidence, location, and number of cranio-orbital foramina within a Caucasian population. METHODS: Forty-seven orbits from 24 formalin-fixed Caucasian cadavers were exenterated. If the cranio-orbital foramen was present within an orbit, its distance from the frontozygomatic suture, supraorbital notch, and Whitnall's tubercle was measured. The gender variations and asymmetric presentations of foramina were studied. RESULTS: The cranio-orbital foramen was present in 26 orbits (55 percent). The average distance from the frontozygomatic suture, supraorbital notch, and Whitnall's tubercle was 30.92 mm (±4.37 mm), 37.77 mm (±3.55 ±), and 29.69 mm (±3.89 mm), respectively. In nine orbits (19 percent), an additional accessory cranio-orbital foramen was identified. The average distance from the frontozygomatic suture, supraorbital notch, and Whitnall's tubercle was 28.56 mm (±5.00 mm), 32.64 mm (±3.20 mm), and 27.78 mm (±5.24 mm), respectively. CONCLUSION: The presence of the cranio-orbital foramen and other accessory foramina represents a source of hemorrhage that surgeons should be aware of when operating along the lateral orbital wall.

A cadaveric study of ethmoidal foramina variation and its surgical significance in Caucasians.

AIMS: To describe the morphometric and geometric relationships of the medial orbital wall ethmoidal foramina and the orbital apex in a Caucasian population. METHODS: 47 orbits from 24 formalin-fixed cadavers were exenterated. Morphometric measurements were taken between anatomical landmarks located on the medial orbital wall and geometric values were calculated. RESULTS: The average distances from the anterior lacrimal crest to the anterior ethmoidal foramen, posterior ethmoidal foramen and optic canal were 25.61 mm (± 2.25), 36.09 mm (± 3.86) and 43.77 mm (± 2.52), respectively. The average distances from the anterior ethmoidal foramen to the first posterior ethmoidal foramen, last posterior ethmoidal foramen and optic canal were 13.88 mm (± 3.51), 16.60 mm (± 2.19) and 21.65 mm (± 2.59), respectively. The average distances from the first and last posterior ethmoidal foramen to the optic canal were 11.63 mm (± 3.79) and 7.25 mm (± 2.59), respectively. CONCLUSION: The distance between the posterior ethmoidal foramen and optic canal is more than double the distance quoted in the surgical literature. This is due to a high incidence of ethmoidal foramina variation. Surgeons operating on the medial orbital wall of a Caucasian population must be aware of these variations as they are a source of haemorrhage and act as landmarks of proximity to the optic canal.

Morphometric and geometric anatomy of the caucasian orbital floor.

INTRODUCTION: To describe the morphometric and geometric relationships of the orbital floor in a Caucasian population. MATERIALS AND METHODS: Exenterations of 47 orbits from 24 formalin fixed cadavers were performed. Morphometric measurements were taken between anatomical landmarks located along the orbital floor and the orbital apex. The mean measurements were used to calculate geometric data. These results were analysed according to sex and side and compared to results from other ethnic populations. RESULTS: The average distances from the infraorbital foramen to the nasolacrimal fossa, inferior orbital fissure, optic canal and inferior orbital rim were 20.67 mm (± 2.42), 25.40 mm (±2.70), 43.23 mm (±3.35) and 8.95 mm (± 1.53), respectively. The average distances from the tip of the infraorbital groove to the tip of the inferior orbital fissure, lateral aspect of the inferomedial strut, optic canal and the intersection with the inferior orbital fissure were 14.08 mm (±2.41), 12.12 mm (±2.42), 35.02 mm (±3.17) and 20.05 mm (± 2.87), respectively. The distances from the tip of the inferior orbital fissure to the optic canal and the intersection with the inferior orbital groove were 29.56 mm (±2.73) and 13.37 mm (±2.76), respectively. DISCUSSION: Orbital surgeons should be aware of the morphometric relationships of the orbital floor due to the degree of variation that exists between different ethnic groups. Geometric data may be used to provide orbital surgeons with a navigational template that can be used to plan surgery and as a guide intraoperatively.

A cadaveric study of the morphometric and geometric relationships of the orbital apex.

INTRODUCTION: To define the morphometric and geometric relationships which exist at the orbital apex. MATERIALS AND METHODS: Forty-seven orbits from twenty-four formalin-fixed Caucasian cadavers were exenterated and the relevant sutures, fissures and foramina identified. Measurements were taken from the optic canal to anatomical landmarks located along the medial wall, inferior wall and lateral wall of each orbit. Based on the mean results the geometric angles between the different anatomical structures were calculated and used to create three-dimensional models. RESULTS: The mean distances from the midpoint of the optic canal to the superior orbital fissure, inferior orbital fissure and anterior ethmoidal foramen were 10.22 mm, 29.56 mm and 21.65 mm, respectively. The mean distances from the anterior ethmoidal foramen to the superior and inferior orbital fissures were 24.27 mm and 31.93 mm, respectively. The mean distance between the tips of the superior and inferior orbital fissures was 27.70 mm. The mean distances directly from the tips of the superior and inferior orbital fissures and the anterior ethmoidal foramen to the orbital rim were 39.23 mm, 17.11 mm and 18.94 mm, respectively. These values were used to calculate geometric values and create three-dimensional models. DISCUSSION: The orbital apex is a congested structure and the practicing orbital surgeon must have an intimate knowledge of its contents. We have presented novel data, which in conjunction with radiology may be used as both a navigational aid to plan orbital surgery and to guide the surgeon intraoperatively to assess proximity to key anatomical structures.

Normative measurements of the Chinese extraocular musculature by high-field magnetic resonance imaging.

PURPOSE: To establish the normal measurements of diameter and cross-sectional area of the Chinese extraocular muscles (EOMs) and optic nerve-sheath complex (ON) as seen on high-field (3-Tesla; 3T) magnetic resonance imaging (MRI). METHODS: Coronal 3T MRI of the orbit (TR, 700 ms; TE, 15 ms; FOV, 160 mm; matrix, 256 x 256; slice thickness, 1 mm; and slice gap, 0) was performed on 80 normal Chinese volunteers. T1-weighted images were analyzed with computer-assisted segmentation. The diameter and the cross-sectional area of EOMs and the ON were measured from the image plane at the posterior aspect of the globe and at 7 mm behind the globe. The maximum diameter of EOM was measured from their respective reconstructed images. RESULTS: The normal measurement (mean +/- SD) of diameter at the posterior aspect of the globe: medial rectus (MR), 3.6 +/- 0.4 mm; inferior rectus (IR), 3.7 +/- 0.8 mm; lateral rectus (LR), 2.3 +/- 0.5 mm; superior oblique (SO), 2.4 +/- 0.6 mm; and the ON, 5.4 +/- 0.7 mm. The normal measurement of diameter 7 mm behind the globe: MR, 3.2 +/- 0.6 mm; IR, 3.9 +/- 0.8 mm; LR, 4.0 +/- 0.8 mm; SO, 2.2 +/- 0.7 mm; and ON, 4.2 +/- 0.5 mm. The normal measurement of cross-sectional area at the posterior aspect of the globe: superior muscle group (SMG), 28.2 +/- 6.5 mm(2); MR, 25.5 +/- 3.2 mm(2); IR, 26.9 +/- 7.2 mm(2); LR, 17.3 +/- 3.9 mm(2); SO, 10.5 +/- 3.5 mm(2); and ON, 27.6 +/- 6.1 mm(2). The normal measurement of cross-sectional area 7 mm behind the globe: SMG, 24.1 +/- 6.6 mm(2); MR, 19.1 +/- 4.6 mm(2); IR, 29.5 +/- 6.6 mm(2); LR, 32.3 +/- 6.5 mm(2); SO, 9.7 +/- 3.9 mm(2); and ON, 17.1 +/- 2.9 mm(2). The normal measurement of maximum diameter: SMG, 4.8 +/- 1.1 mm; MR, 5.1 +/- 0.9 mm; IR, 5.4 +/- 1.0 mm; and LR, 4.5 +/- 0.9 mm. CONCLUSIONS: The Chinese 3T MRI EOMs and ON normative data may be useful in determining pathologic enlargement of the EOMs and ON in various orbital conditions. (ClinicalTrials.gov number, NCT00348413.).

Variation of angle parameters in asians: an anterior segment optical coherence tomography study in a population of singapore malays.

PURPOSE: To assess variations in angle parameters using anterior segment optical coherence tomography (AS-OCT) and to investigate demographic, ocular and systemic associations of angle width. METHODS: This was a substudy of a population based, cross-sectional survey of 3280 (78.7% response rate) Malay people aged 40 to 80 years in Singapore. All participants underwent a standardized interview and ocular and systemic examination. AS-OCT was performed on 291 consecutive patients in standardized dark conditions. Angle opening distance (AOD-500) and trabecular-iris space area (TISA-500) 500 microm from the scleral spur were determined for the nasal and temporal angles. Anterior chamber depth (ACD) was also measured. RESULTS: AS-OCT measurements were analyzed in 239 (82.1%) right eyes. Mean AOD 500 was smaller in women than in men, both nasally (0.255 vs. 0.293 mm, P = 0.026) and temporally (0.245 vs. 0.286 mm, P = 0.023). Mean TISA-500 was smaller in women in the nasal quadrant only (0.104 vs. 0.117 mm, P = 0.035). Mean ACD was smaller in women than in men (2.71 vs. 2.87 mm, P = 0.001). Multiple linear regression showed that axial length and ACD were significantly associated with AOD-500 and TISA-500 both nasally (adjusted R(2) = 0.34 for AOD-500 and 0.20 for TISA-500) and temporally (adjusted R(2) = 0.35 for AOD-500 and 0.24 for TISA-500). Body mass index, HbA(1c), systolic blood pressure, intraocular pressure, cup-to-disc ratio, and central corneal thickness were not significantly associated with AOD-500, TISA-500, or ACD. CONCLUSIONS: In this Malay population, angle width measured by AS-OCT was smaller in women than in men, and in eyes with shorter axial length and shallower ACD.

Prevalence and causes of low vision and blindness in an urban malay population: the Singapore Malay Eye Study.

OBJECTIVE: To describe the prevalence and causes of low vision and blindness in a Malay population. METHODS: A population-based, cross-sectional study of 3280 participants of Malay ethnicity, aged 40 to 79 years, was conducted. Participants underwent standardized ophthalmic assessments to determine (1) presenting and best-corrected visual acuity according to US and modified World Health Organization definitions of blindness and low vision and (2) the primary causes of visual impairment. RESULTS: Of 4168 eligible individuals, 3280 participated in the study (78.7%). The population-weighted prevalence of bilateral blindness was 0.3% and of bilateral low vision, 4.4% (US definition of presenting visual acuity). After best-corrected visual acuity, the population-weighted prevalence of bilateral blindness was reduced to 0.1% and bilateral low vision to 1.0%. Cataract was the main cause of presenting unilateral (38.9%) and bilateral (65.2%) blindness, whereas undercorrected refractive error was the main cause of presenting unilateral (68.8%) and bilateral (52.2%) low vision. Diabetic retinopathy, age-related macular degeneration, and glaucoma were the other leading causes of blindness and low vision. CONCLUSIONS: The age-standardized prevalences of bilateral blindness and low vision in a Malay population were lower when compared with other Asian studies. Undercorrected refractive error and cataract are the leading causes of visual impairment among the Malay adult population in Singapore.

Determinants of the optic cup to disc ratio in an Asian population: the Singapore Malay Eye Study (SiMES).

OBJECTIVE: To describe the distribution and determinants of the optic cup to disc ratio (CDR) in Malay adults in Singapore. METHODS: This population-based, age-stratified study examined 3280 Malay people aged 40 to 80 years in Singapore. Participants underwent a standardized interview and an ocular examination. A slitlamp examination measured the vertical dimensions of the disc and cup, excluding areas of peripapillary atrophy and the Elschnig scleral ring. RESULTS: Vertical CDR was recorded for 3228 right eyes and 3237 left eyes. The mean (SD) CDR was 0.40 (0.15) in both eyes. The CDR in the right eye increased with age (P < .001) and was greater in men vs women (age-adjusted CDR, 0.42 vs 0.39; P < .001). In multiple linear regression, significant determinants of greater CDR were increasing age, male sex, higher intraocular pressure (IOP), lower diastolic blood pressure, lower body mass index, and previous cataract surgery. Of these, higher IOP was the most important determinant of the CDR. After excluding 149 persons with glaucoma, male sex, higher IOP, lower diastolic blood pressure, lower body mass index, and diabetes mellitus were significant predictors of greater CDR. CONCLUSION: Greater vertical CDR was related to male sex, higher IOP, lower diastolic blood pressure, and lower body mass index.

The prevalence and types of glaucoma in malay people: the Singapore Malay eye study.

PURPOSE: To assess the prevalence and types of glaucoma in an Asian Malay population. METHODS: The Singapore Malay Eye Study is a population-based, cross-sectional survey that examined 3280 (78.7% response) persons aged 40 to 80 years. Participants underwent a standardized clinical examination including slit-lamp biomicroscopy, Goldmann applanation tonometry, and dilated optic disc assessment. Participants who were suspected to have glaucoma also underwent visual field examination (24-2 SITA standard, Humphrey Visual Field Analyzer II), gonioscopy, and repeat applanation tonometry. Glaucoma was defined according to International Society for Geographical and Epidemiologic Ophthalmology criteria. RESULTS: Of the 3280 participants, 150 (4.6%) had diagnosed glaucoma, giving an age- and sex-standardized prevalence of 3.4% (95% confidence interval [CI], 3.3%-3.5%). The age- and sex-standardized prevalence of primary open-angle glaucoma was 2.5% (95% CI, 2.4%-2.6%), primary angle-closure glaucoma 0.12% (95% CI, 0.10%-0.14%), and secondary glaucoma 0.61% (95% CI, 0.59%-0.63%). Of the 150 glaucoma cases, only 12 (8%) had a previous known history of glaucoma. Twenty-seven (18%) eyes had low vision (based on best corrected visual acuity logarithm of the minimal angle of resolution [logMAR] >0.30 to <1.00 in the eye with glaucoma for unilateral cases; and based on the better eye for bilateral cases) and 15 (10%) were blind (logMAR, >/=1.00). CONCLUSIONS: The prevalence of glaucoma among Malay persons 40 years of age and older in Singapore is 3.4%, comparable to ethnic Chinese people in Singapore and other racial/ethnic groups in Asia. As in Chinese, Caucasians, and African people, primary open-angle glaucoma was the main form of glaucoma in this population. More than 90% of glaucoma cases were previously undetected.