Visual acuity screening of children 6 months to 3 years of age

The operant preferential looking (OPL) procedure allows a behavioral estimate of visual acuity to be obtained from children 6 mo to 3 yr of age. In clinical settings, there is often too little time available to obtain an acuity estimate with the standard OPL procedure. The goal of this study was to identify specific spatial frequencies, termed diagnostic grating frequencies, that could enable the OPL technique to be used as a screening procedure under conditions where completion of acuity estimation was not possible. One hundred eighty presumptively normal children, 6, 12, 18, 24, 30, and 36 mo of age, were each tested with up to 20 trials of a potential diagnostic grating frequency to determine the highest spatial frequency grating that could be resolved by 90% of children at each age. For all ages except 18 mo, there existed a spatial frequency that produced uniformly high OPL performance within the age group; this spatial frequency was separated by one-half to one octave from a higher spatial frequency that more than 30% of children at that age failed to detect. These results suggest that at all ages except 18 mo, it should be possible to use the OPL procedure as a vision screening tool by testing individual children with the diagnostic grating frequency appropriate for their age.     

Electrophysiologic evaluation according to ISCEV standards in infants less than 10 years of age

Purpose: To analyze the value of electrophysiologic testing according to standards of the International Society for Clinical Electrophysiology of Vision (ISCEV) in infants less than 10 years of age. Patients and methods: In 64 infants less than 10 years, the results from of age electroretinograms (n = 47), visual evoked potentials (n = 30), or electro-oculograms (n = 1) were recorded. Twenty-nine infants were less than 6 years of age, and 17 infants were less than 3 years of age. Indications for examination were unexplained visual loss in 54 infants and familial hereditary retinal dystrophies in ten infants. Sedation with chloral hydrate was performed in seven children. Results: In 40/64 infants (62 %), the results of electrophysiologic examination were pathologic. In 29 infants visual loss was due to retinochoroidal dystrophies, and in 11 infants it was due to disturbances in the optic pathway. In 7/64, infants the suspected retinochoroidal dystrophy could be excluded. Therefore electrophysiologic testing was diagnostically accurate in 47/64 (73 %) of cases. Conclusion: Electrophysiologic testing according to ISCEV standards can be reliably performed in infants less than 10 years of age. When the indication for electrophysiologic testing is made following meticulous ophthalmologic examination, diagnostic accuracy is given in at least 73 % of cases.      

Astigmatism among students ranging from 6 to 18 years of age

PURPOSE: To determine the prevalence of astigmatism among students ranging from 6 to 18 years of age. MATERIAL AND METHODS: 5023 students from elementary schools, junior high schools and high schools, aged 6-18 years were examined. Measurements of visual acuity as well as retinoscopy after cycloplegia have been carried out. The data was analyzed using chi-square test, and the coefficients of rang Spearman's correlation were calculated. RESULTS: It was found that 4% of the students, aged from 6 to 18 suffers from astigmatism. No influence of the students' age on the prevalence of astigmatism was observed. It was found that astigmatism occurs more frequently among boys rather than girls.     

Some characteristics of saccadic eye movements in children of primary school age

The characteristics of saccadic eye movements have been extensively studied in adults; researches have also been devoted to the saccades of preschool age children. On the contrary, for primary school-age children no data exist; we investigate the eye movements (recorded utilizing an infrared technique) of six children 7 to 11 years old. The main results indicate that the values of some parameters (for example the saccadic latency and duration) are in the same range as the values of the correspondent parameters in adults, while the values of other parameters (in particular peak velocity and mean velocity/peak velocity ratio) are distinctly different from the ones measured in adult subjects.     

Occurrence of hyperopia among students ranging from 6 to 18 years of age

PURPOSE: To determine the prevalence of hyperopia among students ranging from 6 to 18 years of age. MATERIAL AND METHODS: 5023 students from elementary schools, junior high schools and high schools, aged 6-18 years were examined. Measurements of visual acuity as well as retinoscopy after cycloplegia have been carried out. The data was analyzed using chi-square test, u-test and Student's t-test. RESULTS: It was found that 21% of the students, aged from 6 to 18 suffers from hyperopia. It has been observed that from the sixth to the eighteenth years of life along with the age decreases the prevalence of hyperopia. A major decrease in the frequency of hyperopia occurrence among students aged between 6 and 9 years old as well as among those aged 16 and older, has been found. Significant differences between prevalence of hyperopia among boys and girls was not observed.     

Occurrence of anisometropia among students ranging from 6 to 18 years of age

PURPOSE: To determine the prevalence of anisometropia among students ranging from 6 to 18 years of age. MATERIAL AND METHODS: 5023 students from elementary schools, junior high schools and high schools, aged 6-18 years were examined. Measurements of visual acuity as well as retinoscopy after cycloplegia have been carried out. The data were analyzed using chi-square test and the coefficients of rang Spearman's correlation were calculated. RESULTS: It was found that 6% of the students suffer from anisometropia. No influence of the students' age on the prevalence of anisometropia was observed. It was found that anisometropia occurs more frequently among boys than among girls.     

两种结膜松弛症诊断与分级标准对老年人群患病率的调查

目的研究两种结膜松弛症（CCh）诊断与分级标准对老年人群患病率诊断的差异。方法横断面调查研究。采用随机抽样方法在上海市曹杨新村街道抽取桂杨园居委会为调查点．对其中≥60岁老年人进行调查,询问病史,采用裂隙灯显微镜进行眼部检查,分别根据Hoh和Zhang的两种不同诊断和分级标准进行诊断并确立CCh的等级．正式调查前先进行预试验,并保证调查质量。采用独立样本t检验和卡方检验完成统计分析。结果本研究拟调查250人,实际调查246人．受检率为98．4％。其中,根据Hbh的标准确诊为CCh193例（377眼）,患病率78．4％,各年龄段CCh患病眼数比例：60-65岁69.3％,66—70岁72．1％,71—75岁76．0％．76～80岁82．1％,81～85岁89.3％,≥86岁100％。根据Zhang的标准确诊为CCh96例（191眼）,患病率39．0％,各年龄段CCh患病眼数比例：60～65岁31．6％,66～70岁36．5％,71～75岁42-3％,76—80岁42．9％,81-85岁44．6％。两种CCh诊断与分级标准所得患病率比较,差异有统计学意义（X^2=78．91,P〈0．01）。两组患病率均随着年龄增大而增高。结论分别采用Hoh和Zhang的CCh诊断与分级标准调查发现,Hoh所得患病率明显高于Zhang的患病率。Hoh的结膜松弛症诊断与分级标准过于宽泛,Zhang的CCh诊断与分级标准更贴近临床应用。     

Treatment of bilateral refractive amblyopia in children three to less than 10 years of age

PURPOSE: To determine the amount and time course of binocular visual acuity improvement during treatment of bilateral refractive amblyopia in children three to less than 10 years of age. DESIGN: Prospective, multicenter, noncomparative intervention. METHODS: One hundred and thirteen children (mean age, 5.1 years) with previously untreated bilateral refractive amblyopia were enrolled at 27 community- and university-based sites and were provided with optimal spectacle correction. Bilateral refractive amblyopia was defined as 20/40 to 20/400 best-corrected binocular visual acuity in the presence of 4.00 diopters (D) or more of hypermetropia by spherical equivalent, 2.00 D or more of astigmatism, or both in each eye. Best-corrected binocular and monocular visual acuities were measured at baseline and at five, 13, 26, and 52 weeks. The primary study outcome was binocular acuity at one year. RESULTS: Mean binocular visual acuity improved from 0.50 logarithm of the minimum angle of resolution (logMAR) units (20/63) at baseline to 0.11 logMAR units (20/25) at one year (mean improvement, 3.9 lines; 95% confidence interval [CI], 3.5 to 4.2). Mean improvement at one year for the 84 children with baseline binocular acuity of 20/40 to 20/80 was 3.4 lines (95% CI, 3.2 to 3.7) and for the 16 children with baseline binocular acuity of 20/100 to 20/320 was 6.3 lines (95% CI, 5.1 to 7.5). The cumulative probability of binocular visual acuity of 20/25 or better was 21% at five weeks, 46% at 13 weeks, 59% at 26 weeks, and 74% at 52 weeks. CONCLUSIONS: Treatment of bilateral refractive amblyopia with spectacle correction improves binocular visual acuity in children three to less than 10 years of age, with most improving to 20/25 or better within one year.