Biomedical subjects

Gus Gazzard

Publications and source records attributed to Gus Gazzard.

32 records · Page 2Linked to original sources

PubMed2004

Causes of blindness, low vision, and questionnaire-assessed poor visual function in Singaporean Chinese adults: The Tanjong Pagar Survey.

OBJECTIVE: To determine the prevalence rates and causes of low vision, blindness, and patient-assessed deficient visual function among Singaporean Chinese adults. DESIGN: Population-based cross-sectional survey. PARTICIPANTS: Singaporean Chinese adults 40 to 79 years old (n = 1152). METHODS: From an initial sampling frame of 40- to 79-year-old Chinese in the Tanjong Pagar district in Singapore, 2000 subjects were selected using a disproportionate, stratified, clustered, random-sampling method. Of 1717 eligible subjects, 1232 were examined (participation rate = 71.8%), and 80 adults who did not have visual acuity (VA) data were excluded from the analysis. MAIN OUTCOME MEASURES: Bilateral low vision was defined as best-corrected VA (BCVA) worse than 6/18 and 3/60 or better, and bilateral blindness as BCVA worse than 3/60 in the better eye or constriction of the visual field to within 10 degrees of fixation, in accordance with the World Health Organization criteria. Patient-assessed visual function was measured using a modified VF-14 questionnaire. RESULTS: The age- and gender-adjusted prevalence rates were 1.1% (95% confidence interval [CI], 0.6-1.8) for bilateral low vision and 0.5% (95% CI, 0.2-1.1) for bilateral blindness, and the mean visual function score was 98.6. The rates of bilateral low vision and blindness increased with age, whereas visual function scores decreased with age, even after adjusting for gender and education. Cataract accounted for 58.8% of bilateral low vision, 20.0% of bilateral blindness, and 52.0% of poor visual function (score<90). Glaucoma contributed to 60.0% of bilateral blindness. CONCLUSION: The age- and gender-adjusted rates of low vision and blindness were 1.1% and 0.5%, respectively. Glaucoma is a leading cause of blindness in Singaporean Chinese adults, in addition to well-recognized causes in the rest of Asia such as cataract.

Adult↗

PubMed2004

Changes in retinal nerve fiber layer thickness after acute primary angle closure.

PURPOSE: To evaluate the changes in retinal nerve fiber layer (RNFL) thickness in the first 16 weeks after acute primary angle closure (APAC) using scanning laser polarimetry (SLP). DESIGN: Prospective, observational case series. PARTICIPANTS: Thirty-seven Asian subjects with APAC. METHODS: For all cases, APAC had resolved after treatment, and the study was conducted during the follow-up period after the acute episode. Using the GDx Nerve Fiber Analyzer (Laser Diagnostic Technologies, San Diego, CA), the RNFL was assessed in both eyes 2 weeks after APAC, and again after 16 weeks. The SLP parameters were compared between week 2 and week 16 within affected and fellow eyes. A multiple logistic regression analysis was carried out to analyze factors likely to influence RNFL outcome. MAIN OUTCOME MEASURES: Superior and inferior average RNFL thickness. RESULTS: The mean age of study subjects was 60.1+/-10.3 years (range, 46-91 years), and most subjects were female (68%) and Chinese (86%). In APAC eyes, the superior average RNFL thickness decreased from 63.8+/-13.6 microm to 61.4+/-11.2 microm (P = 0.04) and the inferior average RNFL thickness decreased from 69.5+/-14.4 microm to 66.3+/-12.6 microm (P = 0.005). There was also a decrease in inferior ratio (P = 0.008) and ellipse modulation (P = 0.02). In the fellow eyes, there was no difference found between week 2 and week 16 for any of the SLP parameters studied. Logistic regression analysis showed no significant association between developing a 10% reduction in either superior or inferior RNFL thickness with age, gender, history of ischemic risk factors, duration of symptoms during APAC, the level of presenting intraocular pressure (IOP), or the development of a rise in IOP between study visits. CONCLUSIONS: After an episode of APAC, superior and inferior average RNFL thickness was found to decrease significantly from week 2 to week 16.

Acute Disease↗

PubMed2004

Long-term outcomes in asians after acute primary angle closure.

PURPOSE: To determine the long-term outcome of Asian eyes with an acute attack of primary angle closure (APAC) and to identify risk factors at presentation associated with the development of glaucomatous optic nerve damage. DESIGN: Cross-sectional observational case series. PARTICIPANTS: Ninety individuals who were initially seen with APAC 4 to 10 years previously at 2 Singapore hospitals. METHODS: All subjects underwent a complete eye examination, including visual acuity, visual field testing, dilated eye examination, and optic nerve head photography. The optic discs were judged clinically and photographically as to whether there was glaucomatous optic neuropathy present, and visual fields were assessed for corresponding visual field loss. All visual fields and optic nerve photographs underwent a second evaluation by an experienced, but masked, glaucoma specialist, who assessed whether the changes were compatible with glaucoma. MAIN OUTCOME MEASURES: The main outcome measures were blindness (defined as best-corrected visual acuity worse than 6/60 and/or central visual field of less than 20 degrees in the attack eye) and glaucomatous optic neuropathy (GON). RESULTS: A total of 90 of 170 eligible subjects (65.2%) were examined. All subjects were Asian and were predominantly Chinese (78 subjects [86.7%]). There were 61 females (67.8%), and the age of the subjects was 62.0+/-9.0 years (mean +/- standard deviation) at the time of APAC, with a mean duration of 6.3+/-1.5 years from the time of the APAC episode to the study examination. Sixteen (17.8%) subjects were blind in the attack eye; half of the cases of blindness were caused by glaucoma. Forty-three subjects (47.8%) had GON, with 13 eyes (15.5%) having markedly cupped optic discs (cup-to-disc ratio >0.9). Thirty-eight eyes (58%) had best-corrected vision worse than 6/9, with cataract responsible for close to half the cases of poor vision. There were no identifiable risk factors related to the APAC episode that were significantly associated with the presence of GON. CONCLUSIONS: Several years after being seen with APAC, 17.8% of subjects examined were blind in the attack eye, and almost half had glaucomatous optic nerve damage. Vision was also reduced in a large number of individuals, largely from unoperated cataract. Subjects with APAC would benefit from regular follow-up to monitor for visual field decline and glaucoma development.

Acute Disease↗

PubMed2004

Acute primary angle closure: configuration of the drainage angle in the first year after laser peripheral iridotomy.

PURPOSE: To evaluate the changes in the configuration of the drainage angle in the first year after acute primary angle closure (APAC). DESIGN: Prospective observational case series. PARTICIPANTS: Forty-four Asian subjects with APAC. METHODS: Acute primary angle closure cases were treated with medical therapy followed by laser peripheral iridotomy (LPI). Static and dynamic gonioscopies were performed in APAC-affected and fellow eyes before LPI (baseline) and then at 2 weeks, 4 months, and 12 months after presentation. The angles were graded in each quadrant according to the Shaffer scheme, and the number of clock hours of peripheral anterior synechiae (PAS) was recorded. Patients who underwent intraocular surgery at any point during follow-up were excluded from the study. Intraocular pressure (IOP) and medical treatment were documented at each visit, and gonioscopic changes were correlated with the development of elevation in IOP requiring medical treatment. MAIN OUTCOME MEASURES: Average Shaffer grade and the number of clock hours of PAS. RESULTS: The majority of subjects were Chinese (84%) and female (64%), and the mean age was 60.2+/-10.7 years. At presentation, 73% of both affected and fellow eyes had very narrow angles (average Shaffer grade < or = 1), with affected eyes having more extensive PAS (P<0.001), a third of whom had > or =8 clock hours of PAS. In APAC eyes, there was a significant increase in angle width from baseline to 2 weeks after LPI (P = 0.045), but no change in angle width subsequently. Fellow eyes showed a widening of the angle between baseline and week 2 (P = 0.01) and from week 2 to month 4 (P = 0.001). There was no significant change in PAS in either affected or fellow eyes over the 12 months of follow-up. Of the 44 subjects, 19 (41.3%) subsequently developed IOP elevation during follow-up that required treatment. However, there was no difference in angle width or amount of PAS between eyes with and without a subsequent rise in IOP, and the angle configuration did not change significantly in either group over 1 year. CONCLUSION: In Asian eyes with APAC, the angle widened in the first 2 weeks after LPI, but did not change thereafter over 1 year, and the amount of PAS remained stable throughout. The results indicate the effectiveness of LPI in preventing progressive closure of the angle in the first year after APAC.

Acute Disease↗

PubMed2004

Undercorrected refractive error in Singaporean Chinese adults: the Tanjong Pagar survey.

OBJECTIVE: To study the prevalence of undercorrected refractive error and associated sociodemographic factors among Singaporean Chinese adults. DESIGN: Cross-sectional, population-based survey. PARTICIPANTS: Singaporean Chinese adults aged 40 to 79 years (n = 1152). METHODS: The Singapore electoral register of Tanjong Pagar was used as a sampling frame, and disproportionate, stratified, clustered, random sampling was performed. There were 1717 eligible adults and 1232 (71.8%) participated. Analysis was performed among 1152 adults with complete habitual and best-corrected visual acuity data. MAIN OUTCOME MEASURE: Undercorrected refractive error was defined as improvement of better eye visual acuity of at least 2 lines or more with best possible refractive correction. RESULTS: The age- and gender-adjusted rate of undercorrected refractive error standardized directly by age and gender was 17.3% (95% confidence interval, 15.0, 19.5). Undercorrected refractive error rates were more common in older adults who had completed fewer years of education and in those who had cataract. People who did not wear spectacles tended to have poorer vision. CONCLUSIONS: The undercorrected refractive error rate among Singaporean Chinese is relatively common compared with data from other populations.

Adult↗

PubMed2004

Repeatability of IOLMaster biometry in children.

AIMS: This study compares the repeatability of IOLMaster (Zeiss, Oberkochen, Germany) axial dimension measurements and conventional ultrasonography in children. METHODS: A series of IOLMaster (partial coherence interferometry, optical pachometry) and Echoscan (US 800, Nidek, Tokyo, Japan) (ultrasound) measurements were taken on 179 Chinese children (mean age, 10.6 +/- 0.8 years) taking part in a longitudinal study of myopia development, and the measurements were repeated on 37 of these subjects. RESULTS: IOLMaster axial length measurements showed better repeatability (95% limits of agreement for repeatability, -0.047 to 0.038 mm) than Echoscan axial length measurements (95% limits of agreement for repeatability, -0.85 to 0.67 mm). IOLMaster anterior chamber depth measurements also showed better repeatability (95% limits of agreement for repeatability, -0.053 to 0.073 mm) than Echoscan anterior chamber depth measurements (95% limits of agreement for repeatability, -0.57 to 0.49 mm). IOLMaster measurements were, on average, slightly larger than Echoscan measurements for axial length (by 0.14 mm) and anterior chamber depth (0.09 mm). CONCLUSION: Partial coherence interferometry techniques, such as that used by IOLMaster, should be considered as the standard technique for axial length measurement in children because they are noninvasive, highly precise, and easy to use.

Biometry↗

PubMed2004

Corneal thickness determination and correlates in Singaporean schoolchildren.

PURPOSE: To determine the central cornea thickness (CCT) in Singaporean children and to examine the possible relationship between intraocular pressure (IOP) and other biometric factors and CCT. METHODS: This was a cross-sectional study. The subjects (N=652) were obtained from the Singapore Cohort Study of the Risk Factors for Myopia (SCORM). The subjects' ages ranged from 9 to 11 years. There were 485 Chinese, 92 Malayan, and 75 Asian Indian children. Measurement procedures included air-puff tonometry, noncontact slit lamp optical pachymetry, cycloplegic autorefraction, and autokeratometry. RESULTS: The mean CCT was 543.6 +/- 32.0 microm. Chinese children had thicker corneas than Malayan or Indian children (P=0.002). The boys had thicker corneas than girls (P=0.011), but the mean difference was only 6.4 microm. There was high correlation of CCT (r=0.98) and IOP (r=0.88) between right and left eyes. IOP was correlated with CCT (r=0.45, P <0.001). In a multiple linear regression model, each millimeter of mercury of IOP was associated with a CCT difference of 5.90 microm (95% confidence interval [CI], 4.98-6.82). The radius of corneal curvature correlated with CCT (r=0.19, P <0.001). The following parameters were not significantly (P >0.05) associated with CCT: age, family income, father's education, axial length, and spherical equivalent. CONCLUSIONS: The mean CCT in Singaporean children aged 9 to 11 years was 543.6 microm and showed ethnic and gender variation. CCT affected measured IOP and correlated weakly with corneal curvature. Compared with data in adults, a change in CCT was associated with a greater difference in measured IOP.

Anthropometry↗

PubMed2003

Ultrasonographic biomicroscopy, Scheimpflug photography, and novel provocative tests in contralateral eyes of Chinese patients initially seen with acute angle closure.

OBJECTIVES: To compare ocular biometry of the contralateral eyes of individuals seen with acute angle closure (AAC) with eyes of population-based control subjects, and to assess novel provocative tests to study the mechanism of AAC. DESIGN: Prospective case-control study. PARTICIPANTS: Chinese persons seen as incident cases of AAC and Chinese population-based controls. METHODS: Slitlamp assessment, ultrasonographic biomicroscopy, Scheimpflug photography, and provocative testing were performed. MAIN OUTCOME MEASURES: Ocular biometric parameters including anterior chamber depth, limbal anterior chamber depth, axial length, lens thickness, and radius of corneal curvature were obtained. Ultrasonographic biomicroscopy parameters that include the angle-opening distance at 500 micro m and the angle-recess area were noted. Scheimpflug photography produced a single measure of angle width. RESULTS: Contralateral eyes of cases of AAC had shorter axial lengths, shallower anterior chamber depths, thicker lenses, and steeper radii of corneal curvature (P<.01). After adjusting for age and sex, cases had a mean adjusted axial length that was 1.2 mm shorter, an optical anterior chamber depth that was 0.63 mm shallower (24% shallower than controls), and lenses that were, on average, 0.35 mm thicker (P<.01). Furthermore, using multiple logistic regression to adjust for age and sex, patients with primary angle-closure glaucoma were 19 times as likely to have a shallower limbal anterior chamber depth (25%; 95% confidence interval, 8.3-45.2). Adjusting for age and sex, the mean angle-opening distance at 500 microm was 0.14 U less for cases, with a mean of 0.26 U in controls, making the angle-opening distance at 500 microm, on average, 54% less among cases. Scheimpflug photographs revealed an adjusted angle width of 21.6 degrees for controls and 15.1 degrees for cases (P<.05). Dynamic testing showed that the angle of control eyes tended to shallow less when going from light to dark and tended to open more when given 1 drop of pilocarpine hydrochloride. CONCLUSIONS: Contralateral eyes of individuals having an AAC attack tend to be shorter and have more crowded anterior segments than those of healthy controls. These static measures of ocular biometry indicate why some individuals are predisposed to AAC. Dynamic measures of the response to luminance changes and pilocarpine therapy indicate that differential reactions to these stimuli are also associated with an AAC attack.

Acute Disease↗

PubMed2003

A prospective ultrasound biomicroscopy evaluation of changes in anterior segment morphology after laser iridotomy in Asian eyes.

PURPOSE: To prospectively quantify changes in anterior segment morphology after laser iridotomy using gonioscopy and ultrasound biomicroscopy (UBM). DESIGN: Prospective comparative observational case series. PARTICIPANTS: Fifty-five fellow eyes of patients presenting with acute primary angle closure (APAC). METHODS: The fellow eyes of patients presenting with APAC were examined with UBM, A-scan ultrasonography, and optical pachymetry at presentation and 2 weeks after sequential argon/neodymium yttrium-aluminum-garnet laser peripheral iridotomy (LPI). UBM images were analyzed using UBM Pro 2000 software. Baseline measurements were made both under standard lighting conditions and in darkness to look for changes in anterior segment findings. MAIN OUTCOME MEASURES: The degree of angle opening was measured using the angle-opening distance (AOD) at 250 and 500 microm from the scleral spur (AOD250 and AOD500, respectively) and angle recess area (ARA). RESULTS: Fifty-five Asian patients were examined; AOD250, AOD500, and ARA all significantly increased after sequential laser iridotomy (P < 0.002). Gonioscopic grading of the angle opening significantly increased in all 4 quadrants (P < 0.001). The Van Herick grade of limbal anterior chamber depth increased (P < 0.001), whereas the number of eyes classified as occludable decreased (73%-33%, P < 0.001). Anterior chamber depth did not change significantly (2.41 mm +/- 0.28 mm vs. 2.42 mm +/- 0.30 mm, P = 0.43) as measured with optical pachymetry. Increased illumination increased the angle-opening measures, but induced a different alteration in peripheral iris morphology. Illumination-induced changes were greater after iridotomy than before laser treatment. CONCLUSIONS: In Asian eyes at high risk of developing APAC, sequential LPI produced a significant widening of the anterior chamber angle without deepening the anterior chamber centrally. LPI produces changes in iris morphology that are different from those caused by an increase in illumination, indicating that different mechanisms account for angle opening under these 2 conditions.

Acute Disease↗

PubMed2003

Intermediate-term outcome of Baerveldt glaucoma implants in Asian eyes.

PURPOSE: To determine the intermediate-term efficacy and safety of Baerveldt glaucoma implants in Asian eyes with complicated glaucoma. DESIGN: Retrospective, nonrandomized, comparative trial. PARTICIPANTS: One hundred twenty-four Asian patients (124 eyes) with complicated glaucoma. INTERVENTION: Implantation of 54 250-mm(2) and 70 350-mm(2) Baerveldt glaucoma drainage implants at Singapore National Eye Center from 1994 through 1999. MAIN OUTCOME MEASURES: Intraocular pressure, number of glaucoma medications, and complications. RESULTS: The mean follow-up period was 33.4 +/- 14.4 months (mean +/- SD; range, 12-72 months). Intraocular pressure (IOP) was reduced from a mean preoperative IOP of 36.5 +/- 10.7 mmHg (range, 21-80 mmHg) to 15.3 +/- 6.0 mmHg (range, 1-34 mmHg), and the number of glaucoma medications decreased from 2.6 +/- 0.6 (range, 1-5) before the time of surgery to 0.5 +/- 0.9 (range, 0-4) medications at last follow-up. Overall, there were 67 eyes (54%) that were classified as complete successes, 27 eyes (22%) that were qualified successes, and 30 eyes that failed (24%). Postoperative complications occurred in 43 eyes (34.7%), and 21 eyes (17%) required further surgical intervention and revision. There was no statistically significant difference between the 250-mm(2) and 350-mm(2) type of implants in terms of success rates, final IOP, number of medications, and rates of complications. After adjusting for gender, preoperative IOP, and length of follow-up, increasing age (odds ratio [OR], 1.05; 95% confidence interval [CI], 1.01-1.09; P = 0.02) and the number of previous operations performed before implant surgery (OR, 1.57; 95% CI, 1.07-2.31; P = 0.01) were found to be correlated positively with failure. CONCLUSIONS: In Asian eyes with complicated glaucoma, Baerveldt glaucoma implants achieve stable and satisfactory IOP reduction with low incidence of complications in the intermediate term after surgery.

Adolescent↗

PubMed2003

Interventions for angle-closure glaucoma: an evidence-based update.

PURPOSE: To assess the interventions to treat acute angle closure (AAC) and primary angle closure (PAC) with or without glaucomatous optic neuropathy. CLINICAL RELEVANCE: Primary angle closure is one of the leading causes of blindness in East Asia. At present, there are few clinical guidelines on the optimal treatment of AAC or PAC in the affected or contralateral eye. METHODS: All randomized clinical trials, prospective controlled clinical trials, nonprospective controlled clinical trials, and retrospective case series with >50 cases that evaluated treatments for AAC or PAC were included. Studies published in the English language were identified from MEDLINE, PubMed, EMBASE, and the Cochrane Collaborations, as well as by a hand search of the reference lists of important articles. RESULTS: Nine randomized clinical trials and 24 nonrandomized clinical trials and large case series were evaluated. Laser peripheral iridotomy (LPI) has been found to be as effective as surgical peripheral iridectomy in randomized clinical trials of the affected and contralateral eyes of AAC or PAC patients with or without evidence of glaucoma. In another randomized clinical trial, latanoprost was found to decrease intraocular pressure (IOP) more than timolol for PAC in patients for whom LPI alone failed. CONCLUSIONS: This review suggests that LPI should be recommended for the treatment of affected and contralateral eyes of AAC patients. In patients with PAC and insufficient treatment with LPI, latanoprost eye drops may decrease IOP more than timolol. There is still insufficient evidence about other interventions for the treatment of AAC and PAC.

Acute Disease↗

PubMed2003

Optic disc hemorrhage in Asian glaucoma patients.

PURPOSE: To assess the prevalence of optic disc hemorrhage in Asian patients with established glaucoma using a recently described, highly sensitive detection method. MATERIALS AND METHODS: Patients entering a trial of glaucoma filtering surgery in Southeast Asia (The Singapore 5FU Study) were assessed for the presence or absence of optic disc hemorrhage using stereo flicker chronoscopy of stereophotograph pairs. RESULTS: A total of 167 patients (117 males and 50 females) were assessed, of whom 128 were Chinese. Primary open-angle glaucoma was diagnosed in 90 patients, primary angle-closure glaucoma in 69 patients, and pseudoexfoliative or pigment dispersion glaucoma in 7 patients. Five eyes of 5 patients had disc hemorrhage at enrollment (5/167), a rate of 2.99%. Four patients with disc hemorrhage had primary open-angle glaucoma and 1 had primary angle-closure glaucoma. There were no significant differences in global visual field indices, AGIS scores, or intraocular pressures between eyes with and without disc hemorrhage. All disc hemorrhages were seen in eyes prior to trabeculectomy. CONCLUSIONS: The prevalence of disc hemorrhage in the current study was comparable to that seen in primary open-angle glaucoma in clinic-based studies of white patients, but far less than that reported in normal-tension glaucoma studies. Hemorrhages were more common in primary open-angle glaucoma than primary angle-closure glaucoma.

Ethnicity↗

PubMed2002

The severity and spatial distribution of visual field defects in primary glaucoma: a comparison of primary open-angle glaucoma and primary angle-closure glaucoma.

OBJECTIVE: To compare the characteristics of visual field defects in primary angle-closure glaucoma (PACG) and primary open-angle glaucoma (POAG). METHODS: Subjects with primary glaucoma aged 30 years and older were prospectively considered for inclusion. Automated static white-on-white perimetry was performed. A minimum of 2 reliable tests was required with a mean deviation (MD) within 2 dB on 2 tests. Subjects with previous symptomatic angle-closure, normal-tension glaucoma, visually significant cataract, or previous intraocular surgery were excluded. RESULTS: Of 234 subjects assessed, 129 had POAG, and 105 had PACG. The MDs (POAG group, -13.3 dB; PACG group, -18.0 dB) indicated more severe visual loss in subjects with PACG. In subjects with POAG, the superior hemifield was more severely affected than the inferior. This was less pronounced in subjects with PACG. Following stratification by MD, the difference between hemifields was marked in the mild (-10 dB<or=MD) and moderate (-20 dB<or=MD<-10 dB) subgroups but was not present in the severe (MD<-20 dB) subgroup. We detected differences between POAG and PACG in retinal sensitivity between the superior and inferior hemifields, independent of severity of damage. CONCLUSIONS: The pattern of visual field loss was different in the 2 diseases. This may give insight into the pattern of visual loss in predominantly pressure-dependent glaucomatous optic neuropathy.

Aged↗

PubMed2002

Prevalence rates of refractive errors in Sumatra, Indonesia.

PURPOSE: To determine the prevalence rates of myopia, hyperopia, astigmatism, and anisometropia in a prevalence survey of adults in Sumatra, Indonesia. METHODS: A population-based prevalence survey of 1043 adults 21 or more years of age was conducted in five rural villages and one provincial town of the Riau Province, Sumatra, Indonesia. A one-stage household cluster sampling procedure was used wherein 100 households were selected from each village or town. Refractive error measurements were obtained with one of two handheld autorefractors. Household interviews were conducted to obtain information on relevant lifestyle risk factors. RESULTS: The age-adjusted overall prevalence rates of myopia (SE [spherical equivalent] at least -1.0 D), hyperopia (SE of at least +1.0 D), astigmatism (cylinder of at least -1.0 D), and anisometropia (SE difference of +1.0 D) were 26.1% (95% confidence interval [CI]: 23.4-28.8), 9.2% (95% CI: 7.4-11.0), 18.5% (95% CI: 16.2-20.8), and 15.1% (95% CI: 12.9-17.4), respectively. The age-adjusted overall prevalence rate of high myopia (SE at least -6.0 D) was 0.8% (95% CI: 0.2-1.5). In a multiple logistic regression model, myopia rates varied with age and increased with income. Hyperopia, astigmatism, and anisometropia rates were independently higher in older adults. CONCLUSIONS: The prevalence rates of myopia in provincial Sumatra are higher than the rates in white populations, but lower than the rates in other urbanized Asian countries such as Singapore. The prevalence rate of high myopia is lower than in most other populations, and other refractive errors are common.

Adolescent↗