Hwei-Zu Wang

The visual status of children ages 3 to 6 years in the vision screening program in Taiwan.

PURPOSE To investigate the current status of myopia, amblyopia, and strabismus of preschoolers in Taiwan. METHODS The records of a vision screening performed in 2005 at 4 preschools by a tertiary referral medical center in Kaohsiung, Taiwan were reviewed. Cycloplegic refraction, visual acuity by E chart, stereopsis by Titmus and National Taiwan University tests, and ocular alignment were analyzed. RESULTS Most (97.7%) of the children (n = 618) were able to perform visual acuity testing. There was good correlation between the results of cycloplegic spherical equivalent obtained by autorefraction and by retinoscopy (r = 0.934, p < 0.001). The prevalence of amblyopia was about 5%. A trend was found between amblyopia morbidity and the 4 age groups when a single criterion (best-corrected visual acuity <0.7) was used for all ages (decreased amblyopia incidence with increased age; p = 0.028, chi(2) test for trend). The prevalence of myopia was 3.0%, 4.2%, 4.7%, and 12.2% at ages 3, 4, 5, and 6 years, respectively. There was a trend of increased myopia with increased age (p = 0.021, chi(2) test for trend). CONCLUSIONS The prevalence of myopia in children ages 3 to 6 years in Taiwan was high compared with the prevalence in other countries. Criteria for amblyopia based on age difference and on the types of visual acuity test are recommended.

Astigmatism in preschool children in Taiwan.

PURPOSE To elucidate the prevalence of astigmatism and its corneal component, the association between the amount of astigmatism and its axis, and the association between the axis of astigmatism and body mass index (BMI) in Taiwanese preschool children. METHODS In this population-based study we analyzed 2 data sets, one obtained by retrospective review of vision-screening data and another obtained in a prospective observational study. Each study collected data for age, sex, and refraction status. Autokeratometry, height, and weight measurements were obtained only in the observational study. Astigmatism was classified as with-the-rule, against-the-rule, or oblique. RESULTS The prevalence of astigmatism was unassociated with age or sex in both data sets. The retrospective study (1,094 subjects; mean age, 5 years; range, 2.19-7.32 years) revealed that 13.3% of the subjects had astigmatism > or = 1.00 D, and most of them had with-the-rule astigmatism; 4.0% had high astigmatism (>1.50 D). Children with with-the-rule astigmatism had greater mean cylinder power than those with against-the-rule or oblique astigmatism. In the prospective study (190 subjects; mean age, 5.65 years; range, 3.79-6.68 years) astigmatism correlated with its corneal component. Preschoolers with with-the-rule astigmatism and with-the-rule corneal astigmatism had greater BMI and heavier weight than those with against-the-rule or oblique type. CONCLUSIONS Astigmatism is common in Taiwanese preschool children. The predominant types are with-the-rule and oblique astigmatism. Most patients with high astigmatism and high corneal astigmatism have with-the-rule type. High BMI or weight is associated with with-the-rule astigmatism and with with-the-rule corneal astigmatism.

CELLULAR CYTOTOXICITY OF ANTIGLAUCOMA DRUGS IN CULTURED CORNEAL ENDOTHELIAL CELLS

In this study, the various antiglaucoma drugs including betaxolol, timolol, levobunolol, carteolol, brimonidine, dipivefrin, dorzolamide, brinzolamide, latanoprost, unoprostone, and pilocarpine were used to investigate the effects of cellular cytotoxicity in cultured bovine corneal endothelial cells. After exposure to the drugs in three dilutions, 1/100, 1/1,000, and 1/10,000, for 100 minutes, cells were estimated based on the release assay of lactate dehydrogenase (LDH) enzyme. It was found that cellular LDH was significantly released in the medium only at 1/100th dilution of betaxolol, brimonidine, dorzolamide, dipivefrin, latanoprost and unoprostone to 130%, 123%, 145%, 157%, 128% and 237%, respectively, compared with controls upon exposure to drugs for 100 minutes. Moreover, benzalkonium chloride preservative at the concentrations ranging from 0.001 to 0.00001mg/mL did not affect cellular LDH release in bovine corneal endothelial cells. These results indicate that high concentrations of antiglaucoma drugs may induce cytotoxicity in corneal endothelial cells.

Uncorrected Visual Acuity and Noncycloplegic Autorefraction Predict Significant Refractive Errors in Taiwanese Preschool Children

PURPOSE To investigate the accuracy of uncorrected visual acuity (UCVA), stereopsis, and noncycloplegic autorefraction (NCAR) tests performed by vision-screening technicians and to determine the best referral criteria when using these methods to screen for significant refractive errors in preschool children. DESIGN Retrospective, case-control, and cross-sectional study. PARTICIPANTS We reviewed 1000 records for a population-based preschool vision-screening program. The target conditions were defined as myopia ≤-3.0 diopters (D), hyperopia ≥ 4.5 D, astigmatism ≥ 2.0 D, and anisometropia ≥ 2.0 D. METHODS Receiver operating characteristic (ROC) curve was used to calculate optimal referral cutoff values. The examination results obtained by the vision-screening technicians were compared with those obtained by a pediatric ophthalmologist, which were considered the gold standard. MAIN OUTCOME MEASURES The efficacies (sensitivity, specificity, positive predictive value, and negative predictive value) of different tests were evaluated. RESULTS In 7.0% (95% confidence interval [CI], 5.3-8.7) of the children, at least 1 eye showed 1 of the target conditions. If only the right eyes were considered, the prevalence of target conditions was 4.2% (95% CI, 2.9-5.5). The ROC curve analysis indicated that the NCAR cylinder test (cutoff value ≥ 0.875 D) was the best test for screening target conditions. With regard to age groups, UCVA ≤ 0.75 (Snellen equivalent) and ≤ 0.85 were the best referral criteria for ages ≤ 4 years and ≥ 5 years, respectively. Combining the UCVA test with the NCAR test (the child was referred after failing both tests) increased specificity without significantly decreasing sensitivity. CONCLUSIONS The UCVA and NCAR tests performed by vision-screening technicians are adequately sensitive and specific for preschool vision screening. The ROC curve analysis was used for determining the appropriate screening criteria for these tests, and combining the tests increased their accuracy. The screening criteria should be age dependent. When analyzing the test accuracy in ophthalmic problems, if the disease of interest does not symmetrically (in terms of disease severity and prevalence) involve both eyes, the prevalence based on only 1 eye should be interpreted with caution.

Toxic Effects of Mitomycin-C on Cultured Ciliary Process Cells and Trabecular Meshwork Cells

Mitomycin-C has recently become an adjunct medication for inhibition of fibroblast proliferation in glaucoma filtering procedures. Prolonged postoperative ocular hypotony has been a frequent complication of trabeculectomy with mitomycin-C. In order to characterize the hypotony mechanism, we compared the toxic effects of mitomycin-C on cultured rabbit ciliary process cells and trabecular meshwork cells. The results indicate that mitomycin-C has a more marked effect on ciliary process cells on 3H-thymidine uptake than on trabecular meshwork cells at concentrations ranging from 10(-1) to 10(-5) mg/ml after 3-, 5- and 60-min treatment, respectively. The living cells after mitomycin-C treatment were estimated with MTT assay that was converted tetrazolium dye of living cells only into insoluble purple formazan crystals within mitochondria. In the presence of mitomycin-C for 3, 5, and 60 min, the cellular MTT values in ciliary process cells were more decreased than in trabecular meshwork cells. Depolarization of the trabecular meshwork cells with 50 mM KCl led to an increase in intracellular calcium concentration, whereas application of mitomycin-C at 10(-3) mg/ml resulted in decrease of KCl-induced intracellular calcium increase. Mitomycin-C (10(-3) mg/ml) decreased cAMP concentration in ciliary process cells following 3- and 5-min treatment; however, it did not significantly affect the cellular cAMP concentration after only a 1-min exposure. Mitomycin-induced marked ladder pattern of DNA fragmentation was observed in ciliary process tissues after treatment with 10(-1) mg/ml of mitomycin-C for 3 and 5 min. However, the DNA pattern in trabecular meshwork tissues was not obviously affected by mitomycin-C. These findings from our results indicate that mitomycin-induced ocular hypotony may result from damage to both ciliary process and trabecular meshwork tissues.

Cytotoxicity of Intracameral Injection Drugs to Corneal Endothelium as Evaluated by Corneal Endothelial Cell Culture

The cell culture method was used to quantitatively evaluate the cytotoxicity to porcine corneal endothelial cells by drugs in the usual concentrations of intracameral injections (ICI). Time-dependent cytotoxicity of drugs was evaluated quantitatively; dye exclusion assay by trypan blue was used as a viability assay; and cytotoxicity to corneal endothelium was tested using amphotericin-B, amikacin, colistin, sulbenicillin, and cephradine in their original, 10-fold, and 100-fold ICI concentrations. Original and 10-fold ICI concentrations of betamethasone also were used. In original and 10-fold ICI concentrations, only amphotericin-B had significant cytotoxicity. In 100-fold ICI concentrations, amphotericin-B, colistin, and sulbenicillin had significant cytotoxicity. Betamethasone had neither a cytotoxic nor a proliferative effect in its original and 10-fold ICI concentrations. A 0.1-fold ICI concentration of amphotericin-B also showed 42.75% cytotoxicity after a 32-min exposure. Evaluating drug cytotoxicity to corneal endothelium by monolayer cultured cells and the time-dependent cytotoxicity of drugs as a quantitative method is efficient and objective.

The oculocardiac reflex during strabismus surgery: its relationship to preoperative clinical eye findings and subsequent postoperative emesis.

PURPOSE To compare the occurrence of significant bradycardia due to the oculocardiac reflex (OCR) during strabismus surgery and its relationship to preoperative clinical eye findings and subsequent development of postoperative emesis. METHODS The medical records of consecutive patients who underwent strabismus surgery August 2006 to June 2009 were retrospectively reviewed. OCR was defined as presence of dysrhythmia or a sudden heart rate decrease ≥ 20% after traction on the extraocular muscle. OCR incidence was compared between the first, second, and third (if any) extraocular muscles in patients who had multiple-muscle strabismus surgery and also between specific muscles (eg, medial rectus vs lateral rectus muscle). Associations with OCR were compared for different strabismus types. Vomiting was considered postoperative if it occurred before discharge of the patient at noon on the day following surgery. Risk factors for OCR and postoperative vomiting were evaluated by logistic regression analysis. RESULTS A total of 111 records were reviewed; 41 patients (37%) experienced OCR. Incidence of OCR and absence of OCR during traction of the first muscle were significantly associated with events during traction of the second (χ(2) = 36.681, P < 0.001) and third muscles (Fisher exact test, P = 0.030). The best predictors of OCR were the absence of fine stereopsis and a larger number of surgically treated muscles. Of the 111 patients, 30 (27%) who had postoperative vomiting, the best predictors were female sex and young age. CONCLUSIONS In our cohort, patients experiencing intraoperative OCR when the first extraocular muscle was manipulated during multiple-muscle strabismus surgery were likely to experience it again during traction of additional muscles. More severe postoperative vomiting was common in these patients. OCR was associated with the preoperative absence of fine stereopsis.

Effects of Antiglaucoma Drugs on Calcium Mobility in Cultured Corneal Endothelial Cells

The aim of this study was to estimate the effects of various antiglaucoma drugs including betaxolol, timolol, levobunolol, brimonidine, carteolol, dipivefrin, dorzolamide, brinzolamide, latanoprost, unoprostone, and pilocarpine on intracellular free Ca2+ ([Ca2+]i) mobility in cultured bovine corneal endothelial cells. Various antiglaucoma drugs were diluted from original concentrations to 1/100, 1/1,000, and 1/10,000. The [Ca2+]i mobility was studied by spectrofluorophotometry after loading with the ester of fura‐2 (fura‐2/AM). It was found that timolol (58 μM and 5.8 μM), levobunolol (171 μM, 17.1 μM, and 1.71 μM), betaxolol (162 μM, 16.2 μM, and 1.62 μM), carteolol (680 μM and 68 μM), dipivefrin (28 μM and 2.8 μM), dorzolamide (616 μM and 61.6 μM), brinzolamide (260 μM), latanoprost (1.1 μM), unoprostone (28.2 μM, 2.82 μM, and 0.282 μM), and pilocarpine (408 μM and 40.8 μM) induced a significant increase in [Ca2+]i. Nevertheless, only brimonidine (68 μM and 6.8 μM) decreased [Ca2+]i concentration significantly. Benzalkonium chloride preservative did not affect [Ca2+]i after addition of 0.001, 0.0001 and 0.00001 mg/mL to cells. These results indicate that all antiglaucoma drugs may affect the physiologic function of corneal endothelial cells through change of [Ca2+]i.mobility.

Fungal corneal ulcers of onion harvesters in southern Taiwan

Fungal corneal ulcers related to agriculture has been reported throughout the world, especially in tropical areas. Most of them were sporadic and had histories of ocular trauma or use of topical corticosteroids and topical antibiotics. Five onion harvesters had fungal corneal ulcers during the same harvest period in Southern Taiwan. The authors think that this is the first report of a group occurrence relating to agricultural workers. Although all of the patients improved after medical and surgical management, their vision was greatly decreased. It is suggested that the tropical climate, the harvest procedure, the characteristic monsoon, and lack of eye protection were involved. Therefore, the importance of the eye protection, hygiene education, and improving medical care to reduce the occurrence of fungal corneal ulcer in agriculture workers must be emphasised.

Occult plastic intravitreal foreign body retained for 30 years: a case report.

A 41‐year‐old man had suffered trauma to the right eye 30 years ago. In March 1996, he underwent trabeculectomy and peripheral iridectomy under the diagnosis of open angle glaucoma in the right eye. Autoperimetry at that time revealed visual field constriction. In addition, ocular examination showed that the cup/disc ratio of his right eye was increased. Cataract was diagnosed in September 2002 and cataract extraction was performed on October 22, 2002. A plastic intravitreal foreign body was detected during the operation. However, preoperative B‐scan ultrasonography had failed to detect an intraocular foreign body (IOFB), and the previous fluorescein angiography had shown only retinal pigment epithelium changes. This case reminded us that we should be alert to an occult IOFB in the event of ocular trauma, even if none had been detected during prior imaging examinations.