Change in vision disorders among Hong Kong preschoolers in 10 years.

BACKGROUND: To determine the change in refractive error and the prevalence of amblyopia and strabismus among preschool children in Hong Kong over a period of 10 years. DESIGN: Two cross-sectional population-based studies conducted in 1996 to 1997 (part A) and 2006 to 2007 (part B) PARTICIPANTS: Children attending randomly selected kindergarten participated in the study. METHODS: Ocular alignment, visual acuity, cover and uncover tests, cycloplegic refraction, slit-lamp and fundi examination were performed under a standardized testing environment. MAIN OUTCOME MEASURES: The prevalence of amblyopia (best-corrected visual acuity ≤6/12 in one or both eyes, or a bilateral difference of ≥2 best-corrected visual acuity lines), strabismus and significant refractive error (hyperopia ≥+2.50 D; myopia ≥-1.00 D; astigmatism ≥2.00 D) among preschool children. RESULTS: Of the 601 children in part A of the study, reduced visual acuity was presented in 3.8%; whereas strabismus was found in 1.8%. The commonest type of refractive error was astigmatism in 6.3% of children, followed by hyperopia (5.8%) and myopia (2.3%). Among 823 children in part B, reduced visual acuity was presented in 2.7% of children, and strabismus was found in 1.7%. The commonest type of refractive error was myopia (6.3%), followed by astigmatism (5.7%) and hyperopia (5.1%). The percentage of children having myopia has significantly increased (P = 0.001). CONCLUSION: A significant increase in myopia has been noted in Hong Kong preschoolers. Visual screening programmes may need to be tailored to correspond to the local population and be adjusted accordingly from time to time.

Measurement of intraocular pressure with pressure phosphene tonometry in children.

PURPOSE: To study the accuracy and acceptability of intraocular pressure (IOP) measurement by the pressure phosphene tonometer, non-contact tonometer, and Goldmann tonometer in children. METHODS: Fifty children (5 to 14 years old) participated in this prospective comparative study. IOP was measured with the pressure phosphene tonometer, non-contact tonometer, and Goldmann tonometer by three different examiners who were masked to the results. The children were also asked to grade the degree of discomfort from 0 to 5 (0 = no discomfort; 5 = most discomfort). RESULTS: The mean IOPs measured by the Goldmann tonometer, pressure phosphene tonometer, and non-contact tonometer were 15.9 mm Hg (standard deviation [SD]: = 5.5 mm Hg; range: 10 to 36 mm Hg), 16.0 mm Hg (SD: 2.9 mm Hg; range: 12 to 25 mm Hg), and 15.7 mm Hg (SD = 5.1 mm Hg; range: 8 to 32 mm Hg), respectively (P = .722). The mean difference between pressure phosphene tonometer and Goldmann tonometer readings was 2.9 mm Hg and that between non-contact tonometer and Goldmann tonometer readings was 2.1 mm Hg. The 95% confidence interval of the mean difference between pressure phosphene tonometer and Goldmann tonometer readings was -1.07 and 1.19, and that between non-contact tonometer and Goldmann tonometer readings was -1.07 and 0.53. The mean discomfort ratings for the pressure phosphene tonometer, non-contact tonometer, and Goldmann tonometer were 0.6, 2.0, and 2.3, respectively (P < .001). CONCLUSION: Although the pressure phosphene tonometer was less accurate than the non-contact tonometer compared with Goldmann tonometer, it gave a reasonably close estimate and had a high specificity of raised IOP. In addition, measurement by the pressure phosphene tonometer is most acceptable to children. The pressure phosphene tonometer can be considered as an alternative method of IOP measurement in children.

The effect of parental history of myopia on children's eye size and growth: results of a longitudinal study.

PURPOSE: To evaluate the effect of parental myopia on eye size and growth in Chinese children. METHODS: A school-based, cross-sectional survey was performed in Chinese children 5 to 16 years of age. A longitudinal cohort study was conducted 1 year later. The effects of parental myopia, parental education level, and near work performed by the child on the refractive error and ocular biometry of the child were assessed. RESULTS: There were 7560 children enrolled in the initial study (response rate: 76.3%). One year later, 4468 children (response rate: 75.9%) in the original cohort (with the exception of those who had completed primary schooling) were evaluated, to determine eye growth. Although children with a stronger parental history of myopia tended to be less hyperopic before the onset of myopia (spherical equivalent refraction [SER] = 0.43 D, 0.67 D, and 0.68 D in children with two, one, and no myopic parents respectively; P = 0.007), the axial lengths did not follow the same pattern (axial length [AL] = 23.11, 23.07, and 23.15 mm; P = 0.429). Eye growth and myopic shift in refraction occurred more rapidly among children with a stronger parental history of myopia (annual AL growth/myopia progression = 0.37 mm/-0.22 D, 0.26 mm/-0.07 D, and 0.20 mm/-0.02 D in children with two, one, and no myopic parents, respectively; P < 0.001). CONCLUSIONS: Ocular biometric data in Chinese children suggest that parental history of myopia influences the growth rate of the eye, rather than its size before the onset of myopia, as previously reported in Caucasian children. Further longitudinal studies involving children of different ethnicities are warranted.

Topical atropine in retarding myopic progression and axial length growth in children with moderate to severe myopia: a pilot study.

PURPOSE: To study the safety and efficacy of topical 1% atropine eye ointment in retarding myopic progression in children with moderate to severe myopia. METHODS: This was an interventional control study. Children (aged 5-10 years) with myopia of -3.00 diopters (D) or more were treated with 1% atropine ointment once daily for 1 year. Baseline and regular assessments of refractive errors by cycloplegic autorefraction and of axial length were done by ultrasound biometry, and the results were compared with data of control subjects. RESULTS: Twenty-three children (mean age: 7.4 +/- 1.6 years) with moderate to severe myopia, being treated in the Hong Kong Eye Hospital of the Chinese University of Hong Kong, were recruited into the atropine group, and 23 children from the same eye clinic were matched with the study subjects with respect to age, sex, and initial spherical equivalent refraction, as controls. The initial refractive errors were -5.18 +/- 2.05 D and -5.12 +/- 2.33 D in the atropine and the control groups, respectively (P = 0.934). Myopic progression was significantly less (P = 0.005) in the atropine group (+0.06 +/- 0.79 D) than in the control group (-1.19 +/- 2.48 D). Axial length increase was also significantly smaller in the atropine group (0.09 +/- 0.19 mm) than in the control group (0.70 +/- 0.63 mm) (P = 0.004). One child (4.3%) developed an allergic reaction. No other major adverse effects related to the treatment were noted. CONCLUSION: Topical 1% atropine ointment is a safe and effective treatment for retarding myopic progression in moderate to severe myopia. Further large-scale randomised controlled study with longer follow-up seems warranted.

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.

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.

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

Orthokeratology lens-related Pseudomonas aeruginosa infectious keratitis.

PURPOSE: To report a case of orthokeratology lens-related Pseudomonas corneal ulcer in an adult. METHODS: Case report. RESULTS: A 37-year-old man presented with a 1-day history of painful red eye. He was a soft contact lens wearer before he started on nocturnal orthokeratology lens wear of 8 to 10 hours per night 9 months ago. Corneal scraping sent for culture revealed a heavy growth of Pseudomonas aeruginosa. The patient was treated with intensive topical fortified tobramycin and ceftazidime drops. The ulcer healed with a residual paraxial corneal scar. Although his best-corrected visual acuity (BCVA) recovered from finger counting (8/200) at presentation to 20/30, he suffered visual loss from a premorbid BSCVA of 20/15. His contrast sensitivity (Vector Vision CSV 1000 test) performance was also worse than his fellow eye. CONCLUSION: Nocturnal orthokeratology lens wear may be associated with an increased risk of infection.

Outcomes of primary rhegmatogenous retinal detachment in myopes of five or more diopters.

OBJECTIVE: To analyze surgical outcomes of primary rhegmatogenous retinal detachment in high myopes. MATERIALS AND METHODS: Medical records of 201 patients who underwent vitreoretinal surgeries for primary retinal detachments were reviewed. Fifty-two eyes of 51 patients with at least 5.00 diopters (D) of myopia were included. RESULTS: The mean refractive error was -9.8+/-5.4 D (mean +/- SD). Macula was off in 29 (55.8%) eyes. Thirty-six (69.2%) and 16 (30.8%) eyes received scleral buckling (SB) and pars plana vitrectomy (PPV), respectively. Primary anatomical success rate was 86.1% and 75.0% in the SB and PPV group, respectively. The anatomical success rate after 2 operations was 94.4% and 100% in the SB and PPV group, respectively. Twenty-three (63.1%) patients from SB group and 10 (62.5%) patients from PPV group attained postoperative best-corrected visual acuity of 20/60 or better. CONCLUSION: The anatomical and visual outcomes of primary rhegmatogenous retinal detachment in myopes of five or more diopters seem favorable after surgery.