25-Gauge transconjunctival sutureless vitrectomy system in the surgical management of children with posterior capsular opacification

PURPOSE

To evaluate the safety and efficacy of the 25-gauge transconjunctival sutureless vitrectomy (TSV) system in the surgical management of posterior capsular opacification (PCO) in pseudophakic children.

METHODS

Pars plana membranectomy was performed for PCO in 10 pseudophakic eyes of six children (mean age 35.1 +/- 37.8 months; range 6-93 months) using the TSV system. Surgical technique, intraoperative problems and postoperative complications including wound leakage, hypotony and the need for suturing were recorded.

RESULTS

Wound leakage and other intraoperative problems were not noted in any of the eyes. All eyes showed improvement of visual acuity from a mean of 6/67 before to 6/29 after surgery (P = 0.001). Mean postoperative intraocular pressure (IOP) was 7.8 +/- 3.1 mmHg (range: 3-10 mmHg). Four eyes (40%) had hypotony on the first postoperative day (IOP: 3-5 mmHg), which was transient in three eyes. One eye in a patient with uveitis had persistent hypotony, but hypotony was also present preoperatively, and the postoperative IOP returned to preoperative levels. This eye also developed recurrent PCO and a second capsulotomy was performed using the 25-gauge TSV system.

CONCLUSIONS

Posterior capsulotomy using the 25-gauge TSV system appears to be a safe and effective approach in the management of PCO in pseudophakic children. Advantages include easier manipulation with the smaller instruments in these small eyes, and it can be considered in appropriate cases.

The effect of parental history of myopia on eye size of pre-school children: a pilot study

PURPOSE

To evaluate parental history of myopia as a predictor of refractive error and eye size in Chinese pre-school children.

METHODS

A total of 514 pre-school children (aged 2.3--6.4 years) were examined. Parental history of myopia, amount of near work performed, refractive status and ocular biometry were recorded.

RESULTS

There was no significant difference in spherical equivalent refraction (SER) among children with no myopic parents (mean+0.94+/-0.05 D), one myopic parent (mean+0.77+- 0.07 D) and two myopic parents (mean+0.79+/- 0.12 D) (p=0.102) after controlling for age and amount of near work. Further, children with more myopic parents did not have longer eyeballs (p=0.335).

CONCLUSIONS

In this study in Chinese pre-school children, parental history of myopia was not found to be associated with a myopic refractive error or increased eyeball length. Further studies with larger sample sizes would help to confirm these results.

Ocular hypertensive and anti-inflammatory responses to different dosages of topical dexamethasone in children: a randomized trial

BACKGROUND

The purpose of the present study was to investigate the ocular hypertensive and anti-inflammatory responses to two different dosage schedules of 0.1% topical dexamethasone in a population of Chinese children undergoing strabismus surgery.

METHODS

Children undergoing bilateral strabismus surgeries were randomly assigned to receive topical 0.1% dexamethasone eye drops four times daily (group A) or twice daily (group B) for 4 weeks. Intraocular pressure (IOP) and anti-inflammatory responses were monitored for 8 weeks.

RESULTS

A total of 137 children with mean age 6.5 years (SD, 1.9 years; range, 3-10 years) participated in the study. The IOP increased significantly after 4 weeks in both groups compared to the preoperative values (P < 0.001). Peak IOP ranged from 14.0 to 50.3 mmHg in group A and 11.0-41.3 mmHg in group B. Cases in group A (mean, 13.8 mmHg; SD, 8.4 mmHg) had a greater net increase in IOP than cases in group B (mean, 10.2 mmHg; SD, 6.2 mmHg; P = 0.004). Younger-aged children had higher peak IOP (r = -0.244, P = 0.048), and attained the peak IOP earlier (r = 0.252, P = 0.041) in group A. There was no significant difference in ocular inflammatory response between the two groups.

CONCLUSION

Ocular hypertensive effect to topical 0.1% dexamethasone is dose and age dependent in children. Twice-daily 0.1% topical dexamethasone eye drops control inflammation after strabismus surgery as effectively as four-times-daily dosage, but induces less increase in IOP, and may be a better treatment schedule.

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

PURPOSE

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.

METHODS

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.

RESULTS

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).

CONCLUSION

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.

Intraocular pressure measurement in patients with previous LASIK surgery using pressure phosphene tonometer

PURPOSE

To compare intraocular pressure (IOP) assessment in post-LASIK patients using non-contact tonometry, pressure phosphene tonometry and applanation tonometry.

METHODS

Sixty-two consecutive LASIK patients were analysed preoperatively and postoperatively with non-contact, pressure phosphene and applanation tonometry. Comparisons among these values were assessed with paired sample Student t-test, Pearson's correlation test and Bland-Altman plotting.

RESULTS

There was no significant difference for preoperative IOP measurement between non-contact, pressure phosphene and applanation tonometry. The mean +/-SD difference between the preoperative non-contact tonometry and postoperative pressure phosphene tonometry IOP measurements was 0.80 +/- 2.77 mmHg (P < 0.01). Postoperative applanation tonometry significantly underestimated IOP measurement by 5.45 +/- 2.96 mmHg (P < 0.001) and postoperative non-contact tonometry significantly underestimated IOP measurement by 9.96 +/- 2.25 mmHg (P < 0.001).

CONCLUSION

Pressure phosphene tonometry may provide an alternative method for the assessment of IOP in post-LASIK patients.

Causes of childhood blindness in a school for the visually impaired in Hong Kong

OBJECTIVE

To identify the causes of blindness in children attending a school for the blind in Hong Kong.

DESIGN

Cross-sectional observational study.

SETTING

School for blind children in Hong Kong.

PARTICIPANTS

Eighty-two blind students at the Ebenezer School and Home for the Visually Impaired were examined between December 1998 and August 1999.

MAIN OUTCOME MEASURES

Demographic data were obtained from students and a questionnaire assessment made of their medical and ocular history. Visual acuity was assessed and visual loss classified according to the World Health Organization classification of visual impairment. Complete ophthalmic assessments were performed in all students including slit-lamp examination and dilated binocular indirect ophthalmoscopy.

RESULTS

The mean age of the students was 12.2 years. Ten (12.2%) had a family history of eye disease. Major past medical illnesses were reported in 50% with prematurity and diseases of the central nervous system found in 26.8% and 11.0% of students, respectively. The most common anatomical site for visual impairment was the retina (47.6%), followed by diseases of the optic nerve (14.6%), and diseases of the anterior segment and the lens (14.6%).

CONCLUSIONS

The pattern of childhood blindness in Hong Kong is similar to that seen in other developed countries. Preventable causes of childhood blindness, such as prematurity and birth asphyxia, were responsible for a large proportion of cases. Early diagnosis and treatment of such conditions may reduce the incidence of childhood blindness in Hong Kong.

Clinical implications of promoter hypermethylation in RASSF1A and MGMT in retinoblastoma

We investigated the epigenetic silencing and genetic changes of the RAS-associated domain family 1A (RASSF1A) gene and the O6-methylguanine-DNA methyltransferase (MGMT) gene in retinoblastoma. We extracted DNA from microdissected tumor and normal retina tissues of the same patient in 68 retinoblastoma cases. Promoter methylation in RASSF1A and MGMT was analyzed by methylation-specific PCR, RASSF1A sequence alterations in all coding exons by direct DNA sequencing, and RASSF1A expression by RT-PCR. Cell cycle staging was analyzed by flow cytometry. We detected RASSF1A promoter hypermethylation in 82% of retinoblastoma, in tumor tissues only but not in adjacent normal retinal tissue cells. There was no expression of RASSF1A transcripts in all hypermethylated samples, but RASSF1A transcripts were restored after 5-aza-2'-deoxycytidine treatment with no changes in cell cycle or apoptosis. No mutation in the RASSF1A sequence was found. MGMT hypermethylation was present in 15% of the retinoblastoma samples, and the absence of MGMT hypermethylation was associated (P = .002) with retinoblastoma at advanced Reese-Ellsworth tumor stage. Our results revealed a high RASSF1A hypermethylation frequency in retinoblastoma. The correlation of MGMT inactivation by promoter hypermethylation with lower-stage diseases indicated that MGMT hypermethylation provides useful prognostic information. Epigenetic mechanism plays an important role in the progression of retinoblastoma.

Failure of systemic antibiotic in preventing sequential endogenous endophthalmitis of a bronchiectasis patient

PURPOSE

To report a rare presentation of bilateral, sequential Pseudomonas aeruginosa endogenous endophthalmitis in a woman with bronchiectasis.

DESIGN

Interventional case report.

METHODS

A 69-year-old woman with bronchiectasis developed right and then left endogenous endophthalmitis with the microbial of P. aeruginosa, even though a course of 3-week intravenous ceftazidime antibiotic was prescribed.

RESULTS

The presentation of endogenous endophthalmitis in the right eye was late, and final visual acuity was hand movements. The condition was recognized much earlier in the left eye, and the infection was treated early on with vitrectomy and intravitreal antibiotics. Visual acuity at 1 year was stable at 20/40.

CONCLUSION

Systemic antibiotic failed to eradicate the primary source of Pseudomonas infection in the bronchiectasis patient. Unusual, painful red eye may be the presenting feature of endogenous endophthalmitis. Early vitrectomy may be considered in endogenous endophthalmitis caused by virulent pathogens such P. aeruginosa.

Comparative study on the safety and efficacy of different cycloplegic agents in children with darkly pigmented irides

BACKGROUND

The ideal cycloplegic drug that is safe, effective and convenient in children is not yet available. This study aimed to evaluate the safety and efficacy of three cycloplegic regimens in hyperopic children with pigmented irides. The responses to cycloplegia in different age groups and presence of strabismus were also compared.

METHODS

Tropicamide 0.5% and phenylephrine 0.5% (regimen I), tropicamide 1.0% and cyclopentolate 1.0% (regimen II), and atropine 1.0% (regimen III) were evaluated in 25 children using a crossover study design. Cycloplegic refractions were assessed.

RESULTS

The mean age of the children was 5.7 +/- 2.0 years (range 2.5-10.8 years). Six (24.0%) of them had strabismus. The spherical equivalent (SE) refraction for regimens I, II and III were +5.11 +/- 2.04 D, +5.29 +/- 1.89 D and +5.71 +/- 1.90 D, respectively, and were significant different from the manifest SE (+3.95 +/- 2.17 D) (P < 0.001). There was no statistical difference between regimen I and II in children without strabismus (P = 0.258) or aged older than 5 years (P > 0.050).

CONCLUSION

In older children, regimen I was as effective as regimen II and can be used to avoid cyclopentolate toxicity.

Intravitreal triamcinolone for diabetic macular oedema in Chinese patients: six-month prospective longitudinal pilot study

AIM

To evaluate the safety and efficacy of intravitreal triamcinolone (IVTA) in Chinese patients with diabetic clinical significant macular oedema (CSMO).

METHODS

Eighteen eyes of 17 consecutive patients with CSMO were prospectively recruited and treated with a 4 mg injection of IVTA. Best-corrected visual acuity (BCVA) on the ETDRS chart and central macular thickness (CMT) on optical coherence tomography were measured at baseline weeks 1, 2, 3, and months 1, 2, 3, 4, 5 and 6. Side-effects were monitored.

RESULTS

All patients completed 6 months of follow up. The mean baseline BCVA and CMT were 1.20 +/- 0.31 logMAR units and 552 +/- 179 microm, respectively. Improvements in CMT and BCVA were observed as early as at 1 and 2 weeks, respectively (P < 0.05). Mean BCVA peaked at 2 months (0.97 +/- 0.38 logMAR units) while mean CMT was maximally reduced at 3 months (326 +/- 145 microm). Improvements in BCVA and CMT were less afterwards but still statistically significant at 6 months; the final mean BCVA and CMT were 0.99 +/- 0.36 logMAR units and 427 +/- 145 microm, respectively. A total of 5/18 (28%) eyes developed a transient increase in intraocular pressure. Cataract progression was noted in 2/12 (17%) of the phakic eyes.

CONCLUSIONS

Intravitreal triamcinolone appeared generally safe and effective in Chinese patients with CSMO. Although the improvements in BCVA and CMT were transient, there were residual benefits at 6 months. Due to the transient nature of IVTA, re-treatment seems necessary but the optimal timing and dosage will require further investigations.

Absence of myocilin and optineurin mutations in a large Philippine family with juvenile onset primary open angle glaucoma

PURPOSE

To analyze the role of the two primary open angle glaucoma (POAG) genes, myocilin (MYOC) and optineurin (OPTN), in a large Philippine family segregating autosomal dominant juvenile onset open angle glaucoma (JOAG).

METHODS

The coding sequences of the MYOC and OPTN genes were screened in 27 family members by polymerase chain reaction and direct sequencing. The specific MYOC promoter polymorphism (MYOC.mtl) was identified by restriction endonuclease assay. All of the ABI MD-10 microsatellite markers on chromosomes 1, 2, 3, 7, 8, and 10, which harbor the six known POAG loci, were analyzed for linkage with POAG.

RESULTS

No mutation was identified in this large kindred. Instead, three polymorphisms (-80G->A, -1000G->C, R76K) in MYOC and four polymorphisms (T34T, M98K, R545Q, IVS7+24G->A) in OPTN were found. All markers flanking the six known POAG loci gave LOD scores not more than 1.1. Non-parametric linkage analysis for all these markers resulted in p values more than 0.05.

CONCLUSIONS

Both mutation testing and linkage analysis provide strong evidence against MYOC and OPTN being the causative gene in this large family. It indicates that unidentified genes will underlie the occurrence of glaucoma in this family.

Microsatellite instability and MLH1 promoter methylation in human retinoblastoma

PURPOSE

To investigate the link between microsatellite instability and epigenetic silencing of the MLH1 gene in the human retinoblastoma genome.

METHODS

Methylation at the 5' region of MLH1 was studied, along with its protein expression level by using immunohistochemical staining in 51 retinoblastoma tumors and 2 retinoblastoma cell lines. Also assessed was the genomic stability of 26 retinoblastoma DNAs from microdissected tumor tissue and matched normal retina tissue obtained from the same patient by microsatellite instability (MSI) analysis. The National Cancer Institute-designed reference panel, and 85 markers on chromosomes 1, 6, 9, and 13 were used.

RESULTS

Hypermethylation of the MLH1 promoter was detected in the WERI-Rb1 cell line and in 34 (67%) of the 51 tumors, but not in cell line Y79 and the other 17 tumors. MLH1 hypermethylation was associated with null MLH1 protein expression (P < 0.0005) and with well-differentiated histology (P < 0.05). MSI at three markers (D2S123, D6S470, and D13S265) was frequently identified among 26 retinoblastoma specimens with matched normal DNA. Among these 26 retinoblastomas, high-frequency MSI (MSI-H) tumors were detected in 19% (5/26) and low-frequency MSI (MSI-L) in another 19% (5/26). The remaining 62% (15/26) were genetically stable (MSS). MSI status (MSS, MSI-L, and MSI-H) was not associated with MLH1 promoter hypermethylation (P = 0.088; Kruskal-Wallis test).

CONCLUSIONS

Epigenetic silencing of the DNA repair gene MLH1 by promoter hypermethylation is a frequent event in retinoblastoma. The results showed that somatic genetic changes involving MSI occur in a subset of retinoblastoma and implicated the presence of a defective DNA mismatch repair pathway resulting in MSI in retinoblastoma.

Photodynamic therapy with verteporfin for subfoveal choroidal neovascularisation of pathologic myopia in Chinese eyes: a prospective series of 1 and 2 year follow up

AIMS

To evaluate the visual and fluorescein angiographic outcomes of photodynamic therapy (PDT) with verteporfin in patients with subfoveal choroidal neovascularisation (CNV) caused by pathologic myopia in the Chinese.

METHODS

Prospective, non-comparative, two centre interventional study. Patients with CNV secondary to pathologic myopia of Chinese ethnicity were recruited and treated with a standard regimen of PDT with verteporfin. Results of this study in Chinese eyes with pigmented retinal pigment epithelium were compared with those from the Verteporfin in Photodynamic Therapy (VIP) Study of predominantly white eyes.

RESULTS

Thirty one and 22 eyes that completed the 12 month and 24 month follow up studies respectively were analysed. The mean and median best corrected visual acuities (BCVA) could be maintained at the baseline level at the 12 month and 24 month visits. Fourteen (63.6%) eyes had stable or improved BCVA at 24 months and six (27.3%) of them had a moderate gain in vision (improved by three or more lines). Visual results were comparable with that of the VIP study, but the average accumulative PDT treatments required in one and two years were 1.7 and 2.3 respectively, which were significantly less than 3.4 and 5.1 treatments in VIP study. Mean logMAR BCVA of the younger age group (<55 years) at 24 months was 0.41 (SD 0.29), which was significantly better than the older age group (>/= = 55 years) of 0.82 (SD 0.40) (Mann-Whitney U test, p = 0.029).

CONCLUSIONS

PDT using the predetermined treatment protocol has achieved similar visual outcomes in the Chinese population as in white people with subfoveal myopic CNV over a 2 year study period. The complete cessation of CNV leakage can be accomplished, on average, with fewer PDT retreatments than reported in the VIP study. The disparity may be due to ethnic differences in these two populations.

Polymorphisms in the Myocilin Promoter Unrelated to the Risk and Severity of Primary Open-Angle Glaucoma

PURPOSE

To investigate the proximal 2.5 kb promoter in the myocilin (MYOC) gene for mutations in Chinese patients with primary open-angle glaucoma (POAG).

PATIENTS AND METHODS

We screened for sequence alterations in the MYOC promoter in 88 unrelated Chinese patients with POAG and 94 unrelated individuals without glaucoma, aged 50 years or above, as control subjects. In addition, the specific MYOC.mt1 polymorphism was determined in a total of 212 POAG patients and 221 control subjects. The relationships between POAG phenotype and the identified polymorphisms were studied by univariate analysis, multivariable logistic regression analysis, and haplotype analysis.

RESULTS

All polymorphisms identified in this study followed Hardy-Weinberg equilibrium (P > 0.12) both in POAG patients and controls. Both univariate and multivariable logistic regression analyses showed no polymorphism that was significantly associated with the risk of POAG, P > 0.08 and P > 0.044 respectively. Haplotype analysis further indicated no association of MYOC promoter polymorphisms with the susceptibility for POAG (P > 0.1). On the other hand, there was no difference of POAG phenotypes among different genotypes of MYOC.mt1 (P > 0.31).

CONCLUSIONS

In this study on the Chinese population, polymorphisms in the MYOC promoter are not related to the risk of POAG. There is no association between the MYOC.mt1 promoter polymorphism with the severity of POAG.

Pressure Phosphene Self-Tonometry: A Comparison with Goldmann Tonometry in Glaucoma Patients

PURPOSE

To evaluate whether the pressure phosphene tonometer (PPT) is suitable for self-tonometry in patients with glaucoma or ocular hypertension.

METHODS

This was a prospective comparative study of 102 eyes of 102 patients with chronic glaucoma or ocular hypertension. Intraocular pressure (IOP) measurements by the Goldmann tonometer (GT) were compared with self-measured readings with the PPT. Patients evaluated the ease of home use of the PPT. The last 15 patients were asked to stop their glaucoma medications, and the ability of the PPT to detect an elevated IOP during self-tonometry was studied.

RESULTS

The mean +/- SD difference between PPT and GT readings was -0.24 +/- 1.57 mm Hg. Comparing the PPT with the GT, 86% of the readings were within +/- 2.0 mm Hg, and 91% were within +/- 3.0 mm Hg. Spearman's correlation coefficient was 0.91. A Bland-Altman plot showed that the 95% limits of agreement between the two methods lay between 2.90 and -3.38 mm Hg. Within-subject coefficients of variation for the GT and the PPT were 4.4% and 7.3%, respectively. In detecting an elevated IOP of more than 21 mm Hg, the sensitivity and the specificity of the PPT were 92.3% and 98.6% respectively. The mean satisfaction score for home use of the PPT was 87.4 +/- 16.3 (maximum 100).

CONCLUSIONS

With proper training and technique, self-tonometry with the PPT appears to be accurate up to at least 25 mm Hg and is reproducible. The PPT was sensitive and specific in detecting an elevated IOP of more than 21 mm Hg. As patients were expected to seek ophthalmic care before the self-measured IOP reaches 25 mm Hg, the PPT may have a value for self-monitoring. Patients rated the PPT as satisfactory for home use. Because the PPT is portable and relatively inexpensive and requires no topical anesthesia or direct contact with the eyeball, it may have potential as an instrument for home self-tonometry.

Ocular manifestations and surgical management of lid coloboma in a Chinese infant with linear nevus sebaceous syndrome

An 8-month-old Chinese girl with linear nevus sebaceous syndrome had a right upper lid coloboma and right superior scleral ectasia. At 20 months old, successful surgical repair of the lid coloboma was performed with particular attention paid to the sclera ectasia.

Long-term results of autogenous palmaris longus frontalis sling in children with congenital ptosis

PURPOSE

To investigate the long-term outcome of using autogenous palmaris longus tendon (PLT) sling for correcting congenital ptosis in children.

METHODS

This is an observational case series involving 15 eyelids of 14 consecutive children with congenital ptosis who underwent frontalis suspension surgery using PLT in a university teaching hospital.

RESULTS

One child had bilateral ptosis and the other children had unilateral ptosis. The age of patients at the time of surgery ranged from 2 to 7 years, with an average of 4.7 years. At a mean follow-up of 92 months (range, 80-104 months), all eyelids were successfully corrected with good lid height. No recurrence or other postoperative complications were encountered except one patient who developed a small skin fold over the PLT harvest site.

CONCLUSION

Long-term lid position is remarkably stable after surgical correction using PLT. PLT sling appears to be a safe and effective treatment for children with congenital ptosis requiring frontalis sling operation. It could be a good alternative to autogenous fascia lata, and further studies, to compare these two sling materials seem warranted.

Astigmatism in Chinese preschool children: prevalence, change, and effect on refractive development

AIM

To study the prevalence, type, and progression of astigmatism in Chinese preschool children, and its effect on refractive development.

METHODS

A cross sectional study of preschool children was carried out in two randomly selected kindergartens. A cohort study was performed on a subset of children, five years after initial examination. Refractive error (measured by cycloplegic autorefraction) and axial ocular dimensions (measured by ultrasonography) were the main study outcomes.

RESULTS

522 children participated in the study; the mean age was 55.7 months (SD 10.9; range 27 to 77). Mean cylinder reading was -0.65 D (SD 0.58; range 0.00 to -4.75), and with the rule astigmatism was predominant (53%). In the 108 children studied longitudinally, the mean cylinder reading reduced from -0.62 D to -0.50 D (p = 0.019). The presence of astigmatism in initial examination predisposed the eyes towards greater myopisation (p<0.001). In addition, children with increased astigmatism had greater myopic progression (p<0.001) and axial length growth (p = 0.002).

CONCLUSIONS

This study reports a high prevalence of astigmatism in Chinese preschool children. The presence of astigmatism, and particularly with increasing astigmatism, appears to predispose the children to progressive myopia. Further studies are warranted.

Ocular-hypertensive response and corneal endothelial changes after intravitreal triamcinolone injections in Chinese subjects: a 6-month follow-up study

PURPOSE

To assess the intraocular pressure (IOP) and corneal endothelial changes, over a 6-month period, after a single injection of intravitreal triamcinolone (ivTA) in Chinese patients.

METHODS

A total of 43 eyes of 43 consecutive Chinese patients with various macular diseases received a single bolus injection of 4 mg ivTA, of which, 14 eyes with significant cataracts underwent simultaneous phacoemulsification and primary intraocular lens implantation. IOP was measured preoperatively and weekly in the first month, and then monthly until 6 months postinjection. Specular microscopy was performed on 24 of the 29 eyes without simultaneous cataract surgery, preoperatively and at months 1, 3, and 6.

RESULTS

All patients completed 6 months of follow-up. Nine out of 43 (20.9%) eyes had IOP >21 mmHg. Their mean maximum IOP was 29.2 mmHg (range 23.0-37.0), necessitating the use of 2.0 types of topical antiglaucomatous medications on average. The IOP elevation occurred at a mean of 5.2 weeks (range 1-17) postinjection. All IOPs returned to normal, without additional antiglaucomatous medications, by 6 months. There was no statistically significant difference (paired t-test, P<0.05) in the corneal endothelial cell count and other specular microscopy parameters up to 6 months after the injections.

CONCLUSION

A single 4 mg bolus injection of ivTA appeared to have no harmful effects on the corneal endothelium. IvTA caused transient IOP elevations in 20.9% of Chinese patients, similar to that observed in Caucasians. As the IOP rise can occur as early as 1 week after the injection, early monitoring will help its early detection and prevent optic nerve damage.

Prevalence, incidence, and progression of myopia of school children in Hong Kong

PURPOSE

To determine the prevalence, incidence, and progression of myopia of Chinese children in Hong Kong.

METHODS

A cross-sectional survey was initially conducted. A longitudinal follow-up study was then conducted 12 months later.

RESULTS

A total of 7560 children of mean age 9.33 (95% confidence interval [CI] = 9.11-9.45; range, 5-16) participated in the study. Mean spherical equivalent refraction (SER) was -0.33 D (SD = 11.56; range, -13.13 to +14.25 D). Myopia (SER <or= -0.50 D) was the most common refractive error and was found in 36.71% +/- 2.87% (SD) of children. Prevalence of myopia correlated positively with older age. Children aged 11 years were almost 15 times more likely to have myopia than were children younger than 7 years (Odds ratio [OR] = 14.81; 95% CI = 14.17-15.48). Incidence of myopia was 144.1 +/- 2.31 (SD) per 1000 primary school children per annum. Increasing age was correlated with increased incidence of myopia, with highest risk in children ages 11 years (OR = 2.27; 95% CI = 2.11-2.44). The average annual change in SER for children with myopia (SER <or= -0.50 D) was -0.63 D (SD = 3.44) compared with -0.29 D (SD = 2.96) for those who were not myopic at the beginning of the study (P < 0.001).

CONCLUSIONS

The results show that the prevalence and progression of myopia in Hong Kong children was much higher than those previously reported in Western countries. The long-term socioeconomic impact of these findings warrants further studies.