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At least 55 records · Page 3Linked to original sources
PubMed1996

Geometrical technique to determine the influence of monochromatic aberrations on retinoscopy.

A geometrical-optical analysis is developed to predict the reflex observed in retinoscopy. The analysis can be expanded to explain the reflex for an eye with aberrations. The succession of reflexes across the pupil for each position of the retinoscope is represented in a contour plot. The plots demonstrate that retinoscopy can be considered a measure of the transverse ray aberration of the eye. For an eye with simple defocus this causes the typical with and against motions observed with hyperopic and myopic refractive errors. For an eye with aberrations we predict more-complex retinoscopic reflexes. This theory is confirmed by actual measurements on a human eye with known aberrations.

Color Perception↗
PubMedDate not supplied

Comparison of on- and off-axis photorefraction with cycloplegic retinoscopy in infants.

We have compared the performance of an off-axis (knife-edge) photorefractor with that of an on-axis (isotropic) system. Normal infants and children between the ages of 8 and 208 weeks were photographed with each camera both with and without cycloplegia. Refractive errors were estimated for each technique based on equations derived from ray-tracing. These refractions were compared to the results of retinoscopy under cycloplegia. Sensitivity and specificity of the two photorefraction systems were evaluated as a function of the magnitude of meridional hyperopia defined by retinoscopy. We also examined the effect of varying the photorefraction screening criterion. Thirteen percent of the infants in the screening sample presented with +3.50 diopters or more of meridional hyperopia. Using this level of ametropia as a referral criterion, the sensitivity and specificity of the off-axis system for infants without cycloplegia were 83% and 72%, respectively. For the on-axis system, sensitivity and specificity values were 85% and 53%. The use of cycloplegics did not significantly improve the performance of either system, but rather their use degraded the specificity of the on-axis system in the presence of moderate refractive errors. The results of the present study indicate that both on- and off-axis systems are effective in identifying highly ametropic infants, but that the off-axis system results in significantly fewer false positives. Moreover, the off-axis system has the advantages of an inherently greater dynamic range for a fixed camera design, and also more easily interpreted photographs.

Child, Preschool↗
PubMed1976

Eye movement patterns and reading performance in poor readers: immediate effects of convex lenses indicated by book retinoscopy.

Eye movement patterns and reading performance were evaluated in 38 4th and 5th grade male students who were at least 1 year behind in their reading levels. Half of the subjects (Group I) demonstrated a need for convex lenses at near by a book retinoscopy criterion. The remaining subjects (Group II) showed no need for convex lenses at near by the same criterion. The subject's eye movements during reading were recorded by a commercial device called Eye-Trac. These recordings were made with 2 lens applications, plano and +0.50 D, respectively. The number of fixations, regressions, rate of reading, and relative efficiency for each condition (plano and +0.50 D) were calculated. In Group I, 3 of 5 measures showed significant improvement with plus lenses. These subjects showed fewer regressions, increased reading speed, and higher relative efficiency with plus than without. In Group II, 3 of 5 measures showed decrement with plus lenses, while 1 (comprehension) showed improvement. These subjects showed more fixations and regressions and lower relative efficiency with plus than without. It is therefore concluded that convex lenses of low power can have considerable immediate effect on children's reading skills, sometimes helpful and sometimes detrimental, and that proper pretesting with both retinoscopy will aid in the prediction of this effect.

Child↗
PubMed1999

[Prediction of postoperative refraction using intraoperative retinoscopy].

PURPOSE: Postoperative refraction was calculated using aphakic refraction measured with intraoperative retinoscopy, and its clinical usefulness was investigated statistically. OBJECTS AND METHODS: We studied 115 eyes of 89 patients, 28 males and 61 females aged 35 to 90 years, who had received intracapsular insertion of an intraocular lens. To decrease the error in measuring, retinoscopy was performed after the attachment of a hard contact lens of +15 D to the patient's cornea, with the exclusion of high myopia. We modified the Haigis calculation and used it to predict the postoperative refraction. RESULTS: The refraction could be measured in 112 eyes. The mean error between the actual and the predicted (actual minus predicted) in 112 eyes was 0.40 +/- 1.05 (mean +/- standard deviation) D. The mean error calculated using the SRK-II method, the Binkhorst method, and the Holladay method was -0.09 +/- 1.13 D, -0.58 +/- 1.00 D, and -0.44 +/- 1.00 D, respectively. The mean error of the average of these three formulas and our method was 0.15 +/- 0.82 D, -0.09 +/- 0.83 D, and -0.02 +/- 0.82 D, respectively. CONCLUSION: Our method seemed to have the same accuracy as other calculation formulas. By using our method together with other formulas, the postoperative refraction could be predicted more accurately.

Adult↗
PubMed1975

Clinical application of bell retinoscopy.

The procedure of bell retinoscopy is described in detail, including changes in motion, color, and brightness of reflex. The responses are divided into eight categories. Suggestions are included to guide and direct the optometrist in prescribing lenses on the basis of bell retinoscopy.

Child↗
PubMed2000

Comparison of computer-photoscreening with non-cycloplegic retinoscopy for amblyopiogenic risk factors in children.

OBJECTIVE: To determine the sensitivity and specificity of using a computer-photoscreener and non-cycloplegic retinoscopy in the detection of amblyopiogenic factors in nine to fifty months old infants and children. METHODS: Three hundred children, nine to fifty months old, were screened with the computer-photoscreener and non-cycloplegic retinoscopy. With a blinded standardized clinical assessment as the standard, an overall comparison of the sensitivity of and specificity results obtained with the two techniques was made. Photoscreen images on the computer monitor screen were reviewed and analyzed immediately by two independent observers for indicators of amblyopiogenic risk factors. Simultaneously, the results were compared to the findings of a full ophthalmologic examination. RESULTS: The computer-photoscreener revealed a sensitivity of 94.6% and specificity of 90.1%, and the non-cycloplegic retinocopy revealed a sensitivity of 85.7% and specificity of 81.0% for the detection of amblyopiogenic risk factors, including hyperopia (+2.75 D or more), myopia (-1.50 D or more), astigmatism (1.75 D or more), anisometropia (2.00 D or more), ocular misalignment (5 degrees or more), and media opacity (1.5 mm or more). CONCLUSIONS: The computer-photoscreener offers an opportunity to identify problems that limit vision, and could provide a feasible and sufficiently reliable screening technique in infants and preschool children to be screened successfully for amblyopiogenic risk factors.

Amblyopia↗
PubMed1992

Dynamic retinoscopy and accommodation.

The added positive lens power required for low and high neutrals at a distance of 1/3 m is determined as a function of age for a sample of 221 clinically normal subjects, aged between 10 and 80 years. These dynamic retinoscopy results are compared with corresponding laser optometer measurements of the levels of accommodation under each condition. Dark focus (tonic accommodation) measurements are carried out on a further sample of 58 subjects. Although the mean results of dynamic retinoscopy agree with those found by earlier authors, on the basis of our sample it is concluded that the considerable scatter in neutral values found in normal subjects at any age limits the usefulness of the technique as an indication of abnormality in near responses. Much of this scatter in pre-presbyopic subjects appears to be related to individual variation in the level of tonic accommodation, although near phoria may also play some role.

Accommodation, Ocular↗
PubMed1984

Noncycloplegic vs cycloplegic retinoscopy in pre-school children.

Refractive errors in 311 children between the ages of 18 and 48 months were assessed utilizing standard cycloplegic retinoscopy and a noncycloplegic near retinoscopy technique as promulgated by Mohindra. Results from this study indicate little agreement between the two objective refraction methods.

Child, Preschool↗
PubMed1977

An optical evaluation of book retinoscopy.

The technique known as book retinoscopy has been used for more than 25 years to evaluate visual performance. The lack of a clear explanation of the phenomena observed during book retinoscopy has led to some confusion regarding the interpretation of the phenomena. This paper shows that all of the changes that are observed can be explained by the optical effects of accommodative changes and eye movements.

Accommodation, Ocular↗
PubMed1996

Accommodative response in children and young adults using dynamic retinoscopy.

Accommodation in children and non-verbal adults can be difficult to assess using standard subjective techniques and hence is often not evaluated. By using a modification of Nott dynamic retinoscopy, rapid objective evaluation of accommodative function is possible. In this study, accommodative response to a range of accommodative demands was measured in 55 normally sighted children and young adults using dynamic retinoscopy. The data were found to fall into four age groupings: 3-10-year-olds' mean accommodation was accurate to within 0.5 D, although 3-5-year-olds over-accommodated slightly, while 6-10-year-olds under-accommodated. Subjects over 10 years of age showed under-accommodation which increased with accommodative demand. These norms are presented for clinical use against which measurements on an individual paediatric or non-verbal patient can be compared. Future studies will determine whether specific patient populations, e.g. patients with cerebral palsy or low vision, demonstrate normal or reduced accommodation.

Accommodation, Ocular↗
PubMed2004

Sources of normal and anomalous motion in retinoscopy.

PURPOSE: Besides the classic "with," "against," and "neutral" absence of motion, retinoscopic reflexes can display anomalous "with" motion in myopia. A model is presented that explains the source of this anomalous motion, as well as quantifies the appearance of retinoscopic motion in myopia and hyperopia. METHODS: Various 2 x 2 matrices were created to describe schematic eyes for a +20 D trial lens, a Gullstrand #1 schematic eye, and an infant schematic eye. Rays from the retinoscope were traced paraxially through these matrices over a full transit of the retinoscope beam across the pupil. Retinal position of the edge of the reflex visible to the observer was plotted as a function of pupil sizes from 2 mm to 16 mm for -5.00 D and +2.00 D refractive errors for the +20 D trial lens. RESULTS: The edge of the retinoscopic reflex could be formed by one of two sources: the edge of the retinoscope beam itself, or the shadow cast by the beam against the edge of the pupil. Anomalous "with" motion arose in myopia when the edge of the reflex was formed by the edge of the beam. The edge of the beam was also visible in hyperopia but did not create anomalous motion. The retinoscope peephole was not involved in the formation of the edge of the reflex. The degree of anomalous motion increased with greater myopia and pupil size. Measured pupil sizes needed to completely eliminate anomalous motion agreed well with those predicted by the model, except at the largest pupil sizes. The limit for anomalous motion depended only on pupil size, refractive error, and working distance but not on whether the system matrix represented the trial lens, a Gullstrand #1 eye, or an infant eye. CONCLUSIONS: Seeing the edge of the beam at large pupil sizes during retinoscopy creates anomalous "with" motion in myopia but may make the reflex easier to see in hyperopia. Anomalous "with" motion in myopia can be managed by adjustment of pupil size, working distance, or net corrected refractive error. Aside from possible effects of aberrations, retinoscopic motion appears to be consistent across various paraxial optical systems for a given refractive error and pupil size.

Artifacts↗
PubMed2004

Accommodative lag using dynamic retinoscopy: age norms for school-age children.

BACKGROUND: Nott dynamic retinoscopy (DR) is a technique that provides an objective, rapid assessment of accommodative function. Presently there are no data available regarding age norms of accommodative function for school-age children using Nott DR. METHODS: Accommodative responses were assessed in a group of 125 school-age children (4 to 15 years of age) using Nott DR. A range of accommodative demands was included [4 D (25 cm), 6 D (16.7 cm), and 10 D (10 cm)]. All the subjects had fully corrected refractive errors and a binocular visual acuity of at least 6/6. RESULTS: Accommodative responses were assessed successfully at each distance with all the subjects (N = 125). A mean overall lag of accommodation was noted with each age group at each distance tested. Regression analysis demonstrated no significant difference in accommodative responses between age groups (p = 0.531 at 4 D, p = 0.062 at 6 D, and p = 0.883 at 10 D). Therefore, results for all the age categories were grouped together to produce a table of normal ranges of accommodation for children aged 4 to 15 years for the three stimuli demands. The mean lag of accommodation was found to be 0.30 +/- 0.39 D at 4 D, 0.74 +/- 0.58 D at 6 D, and 2.50 +/- 1.27 D at 10 D. The normal ranges of accommodation (95% confidence limits) were 2.94 to 4.46 D at 4 D, 4.12 to 6.40 D at 6 D, and 5.02 to 10.00 D at 10 D. CONCLUSIONS: A comprehensive table has been produced detailing the mean lags and normal ranges of accommodative responses expected for school-age children when using Nott DR. These data allow practitioners and researchers to determine whether accommodative responses measured using Nott DR are within normal limits.

Accommodation, Ocular↗
PubMed1981

[Retinoscopy under cycloplegic and non-cycloplegic conditions in children comparison of measurements of three examiners (author's transl)].

The refractive status of 100 eyes were measured by three ophthalmologists utilizing retinoscopy under non-cycloplegic and cycloplegic conditions. The statistical analysis of the results was done by multiple regression. The retinoscopic measurements of sphere and cylinder of the three examiners show smaller differences under cycloplegic than under non-cycloplegic conditions. The largest differences in the measurements of axis were found in cases of small cylinder power. Especially in children and in patients with strabismus, the authors feel that measurements of the refractive state have to be carried out under cycloplegia.

Accommodation, Ocular↗
PubMed1980

A makeshift retinoscopy rack.

A simple makeshift retinoscopy rack consists of various trial lenses placed into the slots of a nonfrosted, 35-mm slide viewing sheet. It is useful in determining the patient's refractive error at the bedside and in the operating room.

Humans↗
PubMedDate not supplied

The red reflex from retinoscopy's point of view. Reflections on a small area.

The size of the area of retina that is involved in neutralization during retinoscopy is considerably smaller than intuition might suggest. Simple optical analysis reveals this area to be approximately 1/640 the area of the optic disc. This becomes important when retinoscoping high myopes with posterior staphylomas because even minimal misalignment with the visual axis may induce spherical error in the retinoscopic findings.

Humans↗
PubMed1987

Television retinoscopy with a slit-aperture retinoscope and a highly sensitive camera.

The low light level of the retinoscopic reflex and the small aperture required to obtain the customary shape of the reflex make it difficult to photograph the actual reflex for teaching or permanent recording. We describe the design and application of a television retinoscopy system that solves this problem. The system uses a standard streak retinoscope modified to gather more light, a highly sensitive television camera, and an image processor. The system can be used for live demonstration of retinoscopic techniques or for videotape recordings for teaching or research.

Equipment Design↗
PubMed1999

The comparison of cyclopentolate and atropine in patients with refractive accommodative esotropia by means of retinoscopy, autorefractometry and biometric lens thickness.

PURPOSE: In this study, we aimed to compare the cycloplegic effect of cyclopentolate HCI 1% and atropine sulphate 1% in patients with refractive accommodative esotropia by means of retinoscopy, autorefractometer and the measurement of lens thickness by biometry. METHODS: Thirty-two patients with refractive accommodative esotropia aged from 5 to 10 (mean 6.8+/-1.4), had a deviation under 10 prism diopters, and underwent retinoscopic, autorefractometric and biometric study in dry and wet conditions. RESULTS: The retinoscopic, autorefractometric and biometric findings of the right eye were 5.10+/-1.21 diopter (D), 5.03+/-1.20 D, 3.43+/-0.16 mm with cyclopentolate, and 5.2+/-1.2 D, 5.2+/-1.2 D, 3.4+/-0.1 mm with atropine. In the left eye, the measurements were 5.2+/-1.4 D, 5.1+/-1.4 D, 3.5+/-0.2 mm with cyclopentolate, and 5.3+/-1.2 D, 5.20+/-1.3 D, 3.4+/-0.2 mm with atropine, respectively. When these obtained data were compared by the Student's t test no statistical significance was found (p > 0.05). CONCLUSIONS: We suggest that the cyclopentolate cycloplegia applied to the patients with refractive accommodative esotropia is sufficient to produce good cycloplegia, with an effect similar to atropine.

Accommodation, Ocular↗
PubMed2003

The repeatability and validity of dynamic retinoscopy in assessing the accommodative response.

Dynamic retinoscopy (DR) is an objective technique that has been used successfully to examine accommodative function of non-communicative patients. However, there are few studies examining its repeatability and validity. This paper addresses the repeatability and validity of a form of DR (a modified Nott technique), by comparing results to the Shin-Nippon SRW-5000 Autorefractor whose validity and repeatability have previously been demonstrated. Accommodative responses of 41 subjects (aged 6-43 years) were assessed using DR and the Shin-Nippon SRW-5000 Autorefractor. Three different target demands were used (10, 6 and 4 D). DR was shown to be repeatable for all target demands (paired t-test, p > 0.05). The results demonstrated good agreement between the autorefractor and DR. The results of the present study suggest that DR is a repeatable and valid objective technique for assessing accommodative function.

Accommodation, Ocular↗