The authors compared and analysed planned extracapsular cataract extraction(ECCE) and Kelman phacoemulsification(KPE) on the 1000 cases out of 1546 cases which had undergone cataract operation during the period of September, 1983 through June, 1989. The results were as follows; 1. Postoperative visual acuity of 0.5 or better was achieved in 96%(960 eyes) and 1.0 or better in 67.6%(676 eyes). Average of visual acuity was similar each other: 0.92 +/- 0.24 in planned ECCE and 1.00 +/- 0.21 in KPE. 2. The mean spherical equivalent of required spectacle lens power was similar too: -1.07D +/- 1.51 in total, -1.08D +/- 1.57 in planned ECCE and -1.05D +/- 1.42 in KPE. 3. The mean postoperative astigmatism was -0.81D +/- 1.05 in total, -0.98D +/- 1.15 in planned ECCE and -0.54D +/- 0.79 in KPE. There was significant correlation between two groups(P<0.01). 4. The difference between predicted and postoperative refraction in terms of spherical equivalent was -0.36D +/- 1.12 in total, -0.36D +/- 1.12 in planned ECCE and -0.37D +/- 1.11 in KPE with no significant different value. The difference by Binkhorst formula was -0.50D +/- 1.10, and -0.06D +/- 1.09, the significant correlative value by regression SRK formula(P<0.05). 5. Mean changes of corneal refractive power was 0.43D +/- 0.99 in horizontal meridian and -0.21D +/-1.14 in vertical meridian in planned ECCE and 0.23D +/- 0.72 in horizontal meridian and 0.01D +/- 0.90 in vertical meridian in KPE. There was significant correlation between two groups(P<0.01). 6. The correlation between postoperative corneal astigmetism and actual astigmatism by skiascopy was very close: regression coefficient was 0.64087 in total, 0.62698 in planned ECCE and 0.62026 in KPE respectively(P<0.01).
Astigmatism ; Cataract ; Retinoscopy ; Visual Acuity

The purpose of this stastical evaluation was to detect the differences or relationship between the diopters and corneal curvature. The objects were 1761 eyes (890 persons) visited to the eye department, Kyung Hee University Hospital during 22 months from June 1974 to April 1976, of which refractive power was myopic over minus 1 diopter by skiascopy. It was stastically analyzed the relationships between the diopters and curvatures of the cornea, mean and standard deviation, standard error, coefficient of variation, and coefficient of correlation which were obtained by means of student-t test. The following-results were obtaind; 1) The consistent differences in the mean values of horizontal curvature and those of vertical curvature by each diopter were proved to be significant (p<0.05). 2) There were no differences in the horizontal curvature to each diopter (not significant). 3) The differences in the means of vertical curvature between each diopters of the -1.00 ~ 6.75D. was not significant. But the differences between the diopters of the -7.00 ~ -18.00D. and the -1.00 ~ -6.75D. was significant. 4) Dividing the samples by groups of -1.00 ~ -2.75D. (A), -3.00 ~ -6.75D. (B), and -7.00 ~ -18.00D. (C), the differences in the horizontal curvatures between these 3 groups were not significant. 5) The differences in the vertical curvature between group-A and group-B were not stastically significant. But there were significant either between group-B and group-C or between group-A and group-C (p<0.05).
Cornea ; Korea* ; Refractive Errors* ; Retinoscopy

Trephination was performed for the purpose of correction of undercorrection after epikeratoplasty. We classified two group-Delayed regression group represented regression toward myopia more than 3D again after spherical equivalant become stable. Undercorrection group represented remained myopia after epikeratoplasty. Thirteen trephinations were performed on eleven eyes. Mean follow-up period was 22.4 weeks. In skiascopy, totally 1.15D myopia was decreased. In delayed regression group myopia was increased 0.5D, while in undercorrection group, myopia was dereased 3.5D, The results of three eyes in eleven eyse were satisfactory. Those 3 cases were from undercorrection group. The results suggest that trephination might be effective method for correction of remained myopia in undercorrection group.
Epikeratophakia* ; Follow-Up Studies ; Myopia ; Retinoscopy ; Trephining*

Photorefraction was performed in 96 cases(191 eyes) after instillation of tropicamide and cyclopentolate for the purpose of screening procedure. And then refraction was also carried out by retinoscope. From this comparison study, phtorefraction provided data which were very close to those obtained from the conventional retinoscopy.
Cyclopentolate ; Mass Screening ; Retinoscopes ; Retinoscopy ; Tropicamide

The object of this study was to observe the refractive errors obtained by near retinoscopy, retinoscopy under cycloplegia and subjective refraction on 244 Korean eyes with refractive error below the age of 90. The results were as follows; A. Comparision between the refractive errors obtained by retinoscopy under cycloplegia and subjective retraction. 1. The difference of spherical powers was 0.59D. 2. The difference Of spherical powers was 0.49D in myopia and 0.76D in hyperopia. 3. The difference of spherical powers was 0.59D in Group I (under age 10), 0.64D in Group II (age 11~20) and 0.45D in Group III (age 21~30). 4. There was not statistically significant difference of spherical powers among the age groups but between myopia and hyperopia. 5. The difference of cylindrical powers was 0.07D. 6. The difference of cylindrical powers was 0.03D. in Group I, 0.12D in Group II and 0.07D in Group III. 7. There was no statistically significant difference of cylindrical powers among the age groups. B. Comparison between the refractive errors obtained by near retinoscopy and subjective refraction 1. The difference of spherical powers was 0.97D. 2. The difference of spherical powers was 0.92D in myopia and 1.05D in hyperopia. 3. The difference of spherical power was 1.03D in Group I, 0.94D in Group II and 0.92D in Group III. 4. There was neither statistically significant difference of spherical powers among tbe age groups nor between myopia and hyperopia. 5. The difference of cylindrical powers was 0.1D. 6. The difference of cylindrical powers was 0.18D in Group I, 0.11D in Group II and 0.04D in Group III. 7. There was no statistically significant defference of cylindrical powers among the groups. C. In this study, regression formula was Y=0.877+0,724X (X : adjusted spherical power obtained by near retinoscopy Y: spherical power obtained by retinoscopy under cycloplegia).
Humans ; Hyperopia ; Myopia ; Refractive Errors ; Retinoscopy*

Computer adaptive testing (CAT) is a kind of tailored testing, in that it is a form of computer-based testing that is adaptive to each test-taker's ability level. In this review, the impacts of CAT are discussed from different perspectives in order to illustrate crucial points to keep in mind during the development and implementation of CAT. Test developers and psychometricians often emphasize the efficiency and accuracy of CAT in comparison to traditional linear tests. However, many test-takers report feeling discouraged after taking CATs, and this feeling can reduce learning self-efficacy and motivation. A trade-off must be made between the psychological experiences of test-takers and measurement efficiency. From the perspective of educators and subject matter experts, nonstatistical specifications, such as content coverage, content balance, and form length are major concerns. Thus, accreditation bodies may be faced with a discrepancy between the perspectives of psychometricians and those of subject matter experts. In order to improve test-takers' impressions of CAT, the author proposes increasing the target probability of answering correctly in the item selection algorithm even if doing so consequently decreases measurement efficiency. Two different methods, CAT with a shadow test approach and computerized multistage testing, have been developed in order to ensure the satisfaction of subject matter experts. In the shadow test approach, a full-length test is assembled that meets the constraints and provides maximum information at the current ability estimate, while computerized multistage testing gives subject matter experts an opportunity to review all test forms prior to administration.
Accreditation ; Animals ; Cats ; Learning ; Motivation ; Retinoscopy

PURPOSE: It is important to know the accurate refractive error of the patients before LASIK because the amount of ablation is determined by that. We analyzed whether there are differences among the preoperative and postoperative results of cycloplegic retinoscopy (CR), module setting value, and autorefraction with and without cycloplegia (ACR, AMR). METHODS: The manifest and cycloplegic refractions of 104 eyes of 104 patients who underwent LASIK from February 2001 to July 2001 were reviewed. The preoperative and postoperative cycloplegic refraction, autorefraction by Canon RK-5, and module setting value were analyzed. RESULTS: In comparison of the preoperative values, AMR showed myopic shift compared to CR, module setting, and ACR (p<.001). ACR showed hyperopic shift compared to CR (p<0.001). The module setting showed myopic shift compared to CR, but it was not statistically significant. Postoperative mean spherical equivalent was 0.04 +/- 0.67D(range: -1.75 ~ +1.5). In comparison of the postoperative results, ACR showed hyperopic shift compared to CR (p<0.001) and AMR showed myopic shift compared to CR (p<0.001). CONCLUSIONS: As there is a difference between autorefraction and cycloplegic refraction, it is inappropriate to decide the amount of ablation only by one method. Hence when LASIK or LASIK retreatment is planned, cycloplegic refraction as well as autorefraction is necessary.
Humans ; Keratomileusis, Laser In Situ* ; Refractive Errors ; Retinoscopy ; Retreatment

PURPOSE: To evaluate correlations with refractive error, astigmatism and uncorrected visual acuity after Ortho-K LKTM lens wear. METHODS: Sixty-one eyes of 32 patients who had been wearing reverse geometry lenses for over 5 weeks were recruited. Uncorrected visual acuity, subjective refraction on retinoscopy, objective refraction measured by an autorefractometer, and corneal astigmatism were measured by corneal topography before, at 2 days, and 1, 3, and 5 weeks after lenses fitting. RESULTS: Uncorrected visual acuity improved from 0.12+/-0.10 to 0.95+/-0.15 after 5 weeks. Subjective refraction on retinoscopy and objective refraction measures with the autorefractometer were -3.52+/-1.65D and -4.06+/-1.73D, respectively before wearing the lenses. These decreased to -0.08+/-0.40D and -1.98+/-2.04D, respectively after 5 weeks. The astigmatism detected by corneal topography improved from 0.93+/-0.49 to 1.20+/-1.03 after 5 weeks. Uncorrected visual acuity was correlated with the refractive error measured by subjective refraction with retinoscopy rather than that by objective refraction with the autorefractometer. Corneal astigmatism measured by corneal topography correlated with the refraction detected by the autorefractometer. CONCLUSIONS: Subjective refraction by retinoscopy rather than refraction found objectively using the autorefractometer, was highly correlated with uncorrected visual acuity (r=0.77~0.87) which seems to be useful in evaluating myopia patients. The astigmatism determined by autorefractometer examination had high correlation with that determined by corneal topography (r=0.51~0.76). This result appears useful in decisions related to the decentering of lenses.
Astigmatism* ; Corneal Topography ; Humans ; Myopia ; Refractive Errors* ; Retinoscopy ; Visual Acuity*

Currently, three different automated objective refractors are available commercially and are being used throughout the world. The most recently developed objective refractor. Dioptron, is an electro-optical instrument for measuring the refractive state of the eyes. The computer in this instrument takes the measurements and calculates automatically his objective refraction in term of sphere, cylinder and axis corrected for 12mm vertex distance. The motivation for this investigation was the need for a quantitative evaluation of Dioptron to determine how it may be utilized most effectively in clinical practice. The results in this study are based on comparisions of differences between Dioptron and streak retinoscopy which were examined the random samples of 800 eyes. In this analysis, authors found that the Dioptron proved to be more accurate in the cylinder and axis and equivalent in sphere findings when compared to streak retinoscopy although Dioptron could not replace physician's judgement.
Axis, Cervical Vertebra ; Evaluation Studies as Topic ; Motivation ; Retinoscopy*

PURPOSE: To compare the measurements between manifest refraction and cycloplegic refraction using retinoscopy or an autorefractor in children and to investigate factors affecting the difference. METHODS: A total of 388 children with a mean age of 7.4 ± 3.6 years were examined using retinoscopy and a Grand Seiko GR-3500KA autorefractor before and after cycloplegia. We compared the difference in spherical and cylindrical components between refractions and analyzed the results according to gender, age, type of refractive error, amblyopia, strabismus, and neuro-developmental disorder. A difference in refractions of ±0.50 D or more was considered as a significant discrepancy. RESULTS: Before cycloplegia, the spherical portion of the refractive error via autorefractor measurement was more myopic than for the retinoscopic measurement in 47.2% of patients, and the cylindrical portion was greater in 37.1%. The spherical discrepancies were more common in children aged < 7 years, with hyperopia, or amblyopia (respectively, p = 0.002, p < 0.001, and p = 0.033). After cycloplegia, the spherical component of the refractive error by auto-refraction differed from retinoscopic measurement in 29.4% of patients, and the cylindrical portion differed in 30.7%. However, the difference was not significant and there was no difference according to clinical features. More than half of the children with discrepancies in the spherical component between retinoscopic refractions before and after cycloplegia had a discrepancy between auto-refraction and retinoscopic refraction before cycloplegia, and the two discrepancies had a significant correlation. CONCLUSIONS: Auto-refraction after cycloplegia can estimate retinoscopic values partially. Nevertheless, 30% of the children still showed a discrepancy. The discrepancy of manifest refraction or auto-refraction compared to retinoscopic refraction with cycloplegia should be considered in younger children, cases with hyperopia or amblyopia, and cases with a difference in auto-refraction and retinoscopic refraction before cycloplegia.
Amblyopia ; Child* ; Humans ; Hyperopia ; Refractive Errors ; Retinoscopy* ; Strabismus