PURPOSE: Our study provides epidemiologic data on the prevalence of refractive errors in all age group ≥5 years in Korea. METHODS: In 2008 to 2012, a total of 33,355 participants aged ≥5 years underwent ophthalmologic examinations. Using the right eye, myopia was defined as a spherical equivalent (SE) less than -0.5 or -1.0 diopters (D) in subjects aged 19 years and older or as an SE less than -0.75 or -1.25 D in subjects aged 5 to 18 years according to non-cycloplegic refraction. Other refractive errors were defined as follows: high myopia as an SE less than -6.0 D; hyperopia as an SE larger than +0.5 D; and astigmatism as a cylindrical error less than -1.0 D. The prevalence and risk factors of myopia were evaluated. RESULTS: Prevalence rates with a 95% confidence interval were determined for myopia (SE <-0.5 D, 51.9% [51.2 to 52.7]; SE <-1.0 D, 39.6% [38.8 to 40.3]), high myopia (5.0% [4.7 to 5.3]), hyperopia (13.4% [12.9 to 13.9]), and astigmatism (31.2% [30.5 to 32.0]). The prevalence of myopia demonstrated a nonlinear distribution with the highest peak between the ages of 19 and 29 years. The prevalence of hyperopia decreased with age in subjects aged 39 years or younger and then increased with age in subjects aged 40 years or older. The prevalence of astigmatism gradually increased with age. Education was associated with all refractive errors; myopia was more prevalent and hyperopia and astigmatism were less prevalent in the highly educated groups. CONCLUSIONS: In young generations, the prevalence of myopia in Korea was much higher compared to the white or black populations in Western countries and is consistent with the high prevalence found in most other Asian countries. The overall prevalence of hyperopia was much lower compared to that of the white Western population. Age and education level were significant predictive factors associated with all kinds of refractive errors.
Adolescent ; Adult ; Age Distribution ; Aged ; Child ; Child, Preschool ; Cross-Sectional Studies ; Female ; Follow-Up Studies ; Humans ; Male ; Middle Aged ; *Nutrition Surveys ; Prevalence ; Refractive Errors/*epidemiology/physiopathology ; Republic of Korea/epidemiology ; Retrospective Studies ; Risk Factors ; Visual Acuity/*physiology ; Young Adult

PURPOSE: To investigate the effect of watching 3-dimensional (3D) television (TV) on refractive error in children. METHODS: Sixty healthy volunteers, aged 6 to 12 years, without any ocular abnormalities other than refractive error were recruited for this study. They watched 3D TV for 50 minutes at a viewing distance of 2.8 meters. The image disparity of the 3D contents was from -1 to 1 degree. Refractive errors were measured both before and immediately after watching TV and were rechecked after a 10-minute rest period. The refractive errors before and after watching TV were compared. The amount of refractive change was also compared between myopes and controls. The refractive error of the participants who showed a myopic shift immediately after watching TV were compared across each time point to assure that the myopic shift persisted after a 10-minute rest. RESULTS: The mean age of the participants was 9.23 ± 1.75 years. The baseline manifest refractive error was -1.70 ± 1.79 (-5.50 to +1.25) diopters. The refractive errors immediately after watching and after a 10-minute rest were -1.75 ± 1.85 and -1.69 ± 1.80 diopters, respectively, which were not different from the baseline values. Myopic participants (34 participants), whose spherical equivalent was worse than -0.75 diopters, also did not show any significant refractive change after watching 3D TV. A myopic shift was observed in 31 participants with a mean score of 0.29 ± 0.23 diopters, which resolved after a 10-minute rest. CONCLUSIONS: Watching properly made 3D content on a 3D TV for 50 minutes with a 10-minute intermission at more than 2.8 meters of viewing distance did not affect the refractive error of children.
Accommodation, Ocular/*physiology ; Child ; Depth Perception/*physiology ; Disease Progression ; Female ; Humans ; Imaging, Three-Dimensional/*adverse effects ; Male ; Refractive Errors/*physiopathology ; *Television ; Vision, Binocular/*physiology

PURPOSE: To evaluate factors associated with the direction of horizontal deviation in the sensory strabismus of patients with unilateral organic amblyopia. METHODS: The medical charts of 53 patients who had been diagnosed with sensory strabismus between 2000 and 2009 were reviewed retrospectively. The underlying ocular disease, time of onset and the duration of vision impairment, refractive error and axial length of the fixing eye, and the direction and angle of deviation were analyzed to determine the distribution of underlying diseases and any factors relevant to determining the direction of the horizontal deviation. RESULTS: Congenital cataracts were the most common underlying disease, found in 33 patients, followed by acquired cataracts, optic nerve disorders, retinal detachment, glaucoma and lens subluxation. Among the 50 patients with horizontal strabismus, 11 had esotropia and 39 had exotropia. The incidence of esotropia was significantly higher when the fixing eye had hyperopia or emmetropia, than when the eye was myopic. Age of onset of vision deterioration and at diagnosis of sensory strabismus, and the axial length of the fixing eye had no relationship to the direction of horizontal deviation. In addition, the duration of visual impairment had no significant relationship with the direction or extent of horizontal deviation. CONCLUSIONS: The most common cause of sensory strabismus was congenital cataracts and the most frequent type of strabismus was exotropia. With respect to the direction of horizontal strabismus, esotropia occurred significantly more often when the refractive error of the fixing eye was hyperopia or emmetropia than when the fixing eye was myopic.
Adolescent ; Adult ; Amblyopia/*complications/physiopathology ; Cataract/complications/congenital/physiopathology ; Child ; Child, Preschool ; Eye Movements/*physiology ; Female ; Follow-Up Studies ; Humans ; Infant ; Infant, Newborn ; Male ; Oculomotor Muscles/*physiopathology ; Refractive Errors ; Retrospective Studies ; Risk Factors ; Strabismus/etiology/*physiopathology ; Visual Acuity ; Young Adult

PURPOSE: To evaluate the predictability of intraocular lens (IOL) power calculations using the IOLMaster and four different IOL power calculation formulas (Haigis, Hoffer Q, SRK II, and SRK/T) for cataract surgery in eyes with a short axial length (AL). METHODS: The present study was a retrospective comparative analysis which included 25 eyes with an AL shorter than 22.0 mm that underwent uneventful phacoemulsification with IOL implantation from July 2007 to December 2008 at Seoul National University Boramae Hospital. Preoperative AL and keratometric power were measured by the IOLMaster, and power of the implanted IOL was determined using Haigis, Hoffer Q, SRK II, and SRK/T formulas. Postoperative refractive errors two months after surgery were measured using automatic refracto-keratometry (Nidek) and were compared with the predicted postoperative power. The mean absolute error (MAE) was defined as the average of the absolute value of the difference between actual and predicted spherical equivalences of postoperative refractive error. RESULTS: The MAE was smallest with the Haigis formula (0.37 +/- 0.26 diopter [D]), followed by those of SRK/T (0.53 +/- 0.25 D), SRK II (0.56 +/- 0.20 D), and Hoffer Q (0.62 +/- 0.16 D) in 25 eyes with an AL shorter than 22.0 mm. The proportion with an absolute error (AE) of less than 1 D was greatest in the Haigis formula (96%), followed by those in the SRK II (88%), SRK-T (84%), and Hoffer Q (80%). CONCLUSIONS: The MAE was less than 0.7 D and the proportion of AE less than 1 D was more than 80% in all formulas. The IOL power calculation using the Haigis formula showed the best results for postoperative power prediction in short eyes.
Aged ; Aged, 80 and over ; Female ; Humans ; Lens Implantation, Intraocular ; *Lenses, Intraocular ; Male ; Middle Aged ; *Optics and Photonics ; Phacoemulsification ; Postoperative Period ; Refractive Errors/diagnosis/physiopathology ; Retrospective Studies

BACKGROUNDAmblyopia is a common ophthalmological condition and the wavefront aberrometer is a relatively new diagnostic tool used globally to measure optical characteristics of human eyes as well as to study refractive errors in amblyopic eyes. We studied the wavefront aberration of the amblyopic children's eyes and analyzed the mechanism of the wavefront aberration in the formation of the amblyopia, try to investigate the new evidence of the treatment of the amblyopia, especially in the refractory amblyopia.

METHODSThe WaveScan Wavefront System (VISX, USA) aberrometer was used to investigate four groups of children under dark accommodation and cilliary muscle paralysis. There were 45 cases in the metropic group, 87 in the amblyopic group, 92 in the corrected-amblyopic group and 38 in the refractory amblyopic group. One-way analysis of variance (ANOVA), t-test and multivariate linear regression were used to analyze all the data.

RESULTSThird order to 6th order aberrations showed a decreasing trend whereas in the higher order aberrations the main ones were 3rd order coma (Z(3)(-1)-Z(3)(1)), trefoil (Z(3)(-3)-Z(3)(3)) and 4th order aberration (Z(4)(0)); and 3rd order coma represented the highest percentage of all three main aberrations. Within 3rd order coma, vertical coma (Z(3)(-1)) accounted for a greater percentage than horizontal coma (Z(3)(1)). Significant differences of vertical coma were found among all clinical groups of children: vertical coma in the amblyopic group (0.17 +/- 0.15) was significantly higher than in the metropic group (0.11 +/- 0.13, P < 0.05). In addition, the vertical coma in the refractory amblyopic group (0.19 +/- 0.15) was higher compared with the metropic group (P < 0.05), the 5th order aberration (0.11 +/- 0.08) was also significantly higher than in the metropic group (0.07 +/- 0.04, P < 0.05). No significant difference was found in vertical coma and 5th order aberration between the corrected-amblyopic group (0.13 +/- 0.11) and metropic group (0.07 +/- 0.04) (P > 0.05).

CONCLUSIONSAlthough lower order aberrations such as defocus (myopia and hyperopia) and astigmatism are major factors determining the quality of the retinal image, higher order aberrations also need to be considered in amblyopic eyes as their effects are significant.

Aberrometry ; Amblyopia ; pathology ; physiopathology ; Child ; Child, Preschool ; Female ; Humans ; Male ; Refraction, Ocular ; physiology ; Refractive Errors ; diagnosis ; pathology

PURPOSE: To maximize effective use of mydriatic drugs through comparing the pupillary dilation effects between 1% tropicamide and 2.5% phenylephrine. METHODS: Fifty people requiring pupillary dilation were divided into 3 groups. Group 1 was treated with one drop of 1% tropicamide in the right eye and one drop of 2.5% phenylephrine in the left eye. Group 2 was treated twice during a 5-minute interval with 1% tropicamide in the right eye. Group 3 was treated twice during a 5-minute interval with 2.5% phenylephrine in the right eye. Groups 2 and 3 were treated with 2.5% phenylephrine and 1% tropicamide in the left eye, administered during a 5-minute interval. The pupillary size was measured in all groups for 40 minutes following eye drops administration. RESULTS: The mean patient age was 15.7 years. Group 1 included 10 patients, and groups 2 and 3 included 20 patients each. Eight patients in group 1 and 16 patients in group 2 developed a larger right pupil. Fourteen patients in group 3 developed a larger left pupil. CONCLUSIONS: Our study showed that 1% tropicamide, with its parasympathetic antagonistic mechanism of action, was more effective at inducing pupillary dilation than 2.5% phenylephrine, and the combination of 1% tropicamide and 2.5% phenylephrine was more effective than multiple drops of single eye drops.
Adolescent ; Adult ; Child ; Child, Preschool ; Dose-Response Relationship, Drug ; Drug Administration Schedule ; Female ; Follow-Up Studies ; Humans ; Male ; Muscarinic Antagonists/*administration & dosage ; Mydriatics/*administration & dosage ; Ophthalmic Solutions ; Phenylephrine/*administration & dosage ; Pupil/*drug effects ; Refractive Errors/diagnosis/physiopathology ; Retrospective Studies ; Tropicamide/*administration & dosage ; Young Adult

PURPOSE: To evaluate the refractive predictability of a partial coherence interferometry (PCI) biometry device (IOL Master(R)) for cataract surgery and to investigate factors that may affect it. METHODS: Retrospective review of 209 eyes from 151 patients that had undergone preoperative PCI biometry and an uneventful phacoemulsification cataract surgery with posterior chamber intraocular lens (IOL) implantation was conducted. Prediction error defined as the intended refraction minus the postoperative refraction in spherical equivalent (SE) and the absolute error were analyzed according to IOL calculation formulas, patient characteristics, preoperative visual acuity (VA) and refraction, posterior subcapsular cataract (PSC), signal-to-noise ratio (SNR), and axial length (AL). RESULTS: The overall refractive predictability of the PCI device was good. Generally, the SRK/T formula performed better than the SRK-II formula. Refractive predictability was slightly worse in eyes with > or =+2.0 diopters (D) of preoperative SE (with both SRK-II and SRK/T) and in eyes with an AL< or =23.0 mm (only with SRK-II. No other factors significantly affected the refractive predictability of the PCI, although poor VA, dense PSC, and poor SNR were closely interrelated. CONCLUSIONS: The SRK/T formula performed significantly better than the SRK-II formula. Eyes with an AL< or =23.0 mm were associated with significantly greater hyperopic shifts in postoperative refraction with the SRK-II formula, but not with the SRK/T formula. A preoperative SE> or =+2.0D was related to a significantly greater hyperopic shift in postoperative refraction. With proper verification of measured data and a suitable IOL calculation formula, good refractive predictability is expected from PCI biometry regardless of patient characteristics, preoperative VA, SNR, PSC, and AL.
Aged ; Aged, 80 and over ; Female ; Humans ; Interferometry/*methods ; Lens Implantation, Intraocular ; *Lenses, Intraocular ; Light ; Male ; Phacoemulsification/*methods ; *Refraction, Ocular ; Refractive Errors/*diagnosis/physiopathology ; Reproducibility of Results ; Retrospective Studies ; Visual Acuity

PURPOSE: To compare changes of anterior corneal aberration (Pentacam(R)) and ocular aberration (aberrometer, LADARWave(R)) after laser refractive surgery. METHODS: Sixty-six eyes underwent laser refractive surgery and were retrospectively reviewed. Anterior corneal aberration and ocular aberration were measured by Pentacam(R) and an aberrometer (LADARWave(R)) respectively. Changes of root mean square (RMS) values of coma, spherical aberration, and total high order aberration (HOA) were evaluated before, 1 month, and 3 months after surgery RESULTS: Ocular aberrations displayed low preoperative values, but after laser refractive surgery, anterior corneal aberration and ocular aberration increased equally. There were no statistically significant differences of internal optics aberration values (ocular aberration minus anterior corneal aberration) in coma, spherical aberration, and total HOA. Anterior corneal aberration and ocular aberration showed statistically significant correlations at 1 and 3 months after surgery. CONCLUSIONS: Internal optics aberration compensated the anterior corneal aberration effectively before surgery, but the increase of anterior corneal aberration after laser refractive surgery exceeded the compensation of internal optics. As a result, anterior corneal aberration and ocular aberration increased equally. The correlation between anterior corneal aberration and ocular aberration after surgery was statistically significant due to the increased proportion of anterior corneal aberration in ocular aberration.
Adult ; Cornea/*physiopathology ; Corneal Topography ; Humans ; Lasers, Excimer/*therapeutic use ; Myopia/surgery ; Photography ; Refraction, Ocular/*physiology ; Refractive Errors/*physiopathology ; *Refractive Surgical Procedures ; Retrospective Studies

PURPOSE: We analyzed the effect of the changes of the optic disc area (ODA) caused by the axial length and the refractive error, and the consequent changes of the distance from the optic disc margin to the circular scan (OD-CS) of Optical coherence tomography (OCT) on the measurement of the retinal nerve fiber layer thickness(RNFLT) were examined. METHODS: One hundred two eyes of 51 children (age range 4 to 15 years) were measured using OCT including the RNFLT. For the ODA and the OD-CS, the relative area formed by the ODA and the circular scan was obtained. In addition, the correlation of the refractive error and the axial length to the optic disc factors was assessed. RESULTS: As hyperopia progresses to myopia, the axial length became longer, the ODA became smaller (r=-0.442, p=0.000) and the OD-CS showed a tendency to increase (r=0.471, p=0.000). As the OD-CS became longer, the measured average RNFLT decreased significantly (r=-0.248, p=0.012), and the ODA and the OD-CS showed a significant correlation to the RNFL thickness that was measured in the nasal and inferior areas, the S2, N2 and N3 areas and the I1 area. CONCLUSIONS: As ODA becomes smaller and the OD-CS becomes longer, the RNFLT measured in the nasal and inferior areas, the S2, N2, N3, I1 area has a tendency to be thinner. Hence, consideration of the disc area is required when interpreting the RNFLT of these eyes.
Adolescent ; Aging/physiology ; Child ; Child, Preschool ; Female ; Glaucoma/diagnosis ; Humans ; Male ; Nerve Fibers/*pathology ; Optic Disk/*pathology ; Optic Nerve Diseases/*physiopathology ; Refraction, Ocular ; Refractive Errors/*physiopathology ; Retinal Ganglion Cells/*pathology ; Tomography, Optical Coherence ; Visual Acuity

INTRODUCTIONRefractive error remains one of the primary causes of visual impairment in children worldwide, and the prevalence of refractive error varies widely. The objective of this study was to determine the prevalence of refractive error and study the possible associated factors inducing refractive error among primary school children of Malay ethnicity in the suburban area of Kota Bharu, Kelantan, Malaysia.

MATERIALS AND METHODSA school-based cross-sectional study was performed from January to July 2006 by random selection on Standard 1 to Standard 6 students of 10 primary schools in the Kota Bharu district. Visual acuity assessment was measured using logMAR ETDRS chart. Positive predictive value of uncorrected visual acuity equal or worse than 20/40, was used as a cut-off point for further evaluation by automated refraction and retinoscopic refraction.

RESULTSA total of 840 students were enumerated but only 705 were examined. The prevalence of uncorrected visual impairment was seen in 54 (7.7%) children. The main cause of the uncorrected visual impairment was refractive error which contributed to 90.7% of the total, and with 7.0% prevalence for the studied population. Myopia is the most common type of refractive error among children aged 6 to 12 years with prevalence of 5.4%, followed by hyperopia at 1.0% and astigmatism at 0.6%. A significant positive correlation was noted between myopia development with increasing age (P <0.005), more hours spent on reading books (P <0.005) and background history of siblings with glasses (P <0.005) and whose parents are of higher educational level (P <0.005). Malays in suburban Kelantan (5.4%) have the lowest prevalence of myopia compared with Malays in the metropolitan cities of Kuala Lumpur (9.2%) and Singapore (22.1%).

CONCLUSIONThe ethnicity-specific prevalence rate of myopia was the lowest among Malays in Kota Bharu, followed by Kuala Lumpur, and is the highest among Singaporean Malays. Better socio-economic factors could have contributed to higher myopia rates in the cities, since the genetic background of these ethnic Malays are similar.

Child ; Cross-Sectional Studies ; Female ; Follow-Up Studies ; Humans ; Malaysia ; epidemiology ; Male ; Prevalence ; Refraction, Ocular ; Refractive Errors ; complications ; epidemiology ; physiopathology ; Retrospective Studies ; Schools ; Suburban Population ; statistics & numerical data ; Vision, Low ; epidemiology ; etiology ; physiopathology ; Visual Acuity