Screening for amblyopia in preverbal children with photoscreening photographs. III. improved grading criteria for hyperopia

Effects of various hyperopia intervention levels on male college students' gait kinematics

Background: Hyperopia is a common blurred vision phenomenon that affects postural control in gait; however, current research has focused on the alteration and correction of hyperopia's physiological characteristics, ignoring the effect of hyperopia on gait kinematic characteristics. The effect of hyperopia on the basic form of movement walking is a worthy concern. Objective: To investigate the gait kinematic characteristics of male college students with varying degrees of visual acuity (normal vision, hyperopia 150°, and hyperopia 450°), as well as to provide a theoretical foundation for the effect of visual acuity on gait and fall risk reduction. Methods: Twenty-two male college students with normal visual acuity were chosen. Their vision was tested using a standard visual acuity logarithm table at normal and with 150° and 450° concave lenses. Gait kinematic data were collected under normal vision and hyperopic conditions using the PN3 Pro advanced inertial motion capture system and Axis Studio application program. Results and conclusion: 1. The change of center of gravity in Pre-double support was smaller than normal vision; Late-single support and Late-swing was larger than normal vision; 2. The percentage of the double-leg support decreased; the percentage of the single-leg support and the Late-swing increased; 3. For the joints' range of motion, Trunk flexion and extension range of motion in Pre-single support, Late-double support and Pre-swing smaller than normal visual acuity, and Late-swing larger than normal; hip internal abduction and adduction and internal and external rotation are larger than normal vision in Late-single support; knee and ankle in abduction and adduction direction are larger than normal vision in the swing stage; hip flexion and extension, internal external rotation are larger than normal vision in the swing stage. Hyperopic interventions have an impact on the kinematic characteristics of gait in male college students, mainly in terms of altered balance, increased instability, increased difficulty in maintaining trunk stability, and increased risk of injury.

Infant hyperopia: detection, distribution, changes and correlates-outcomes from the cambridge infant screening programs

PURPOSE

To report on two population screening programs designed to detect significant refractive errors in 8308 8- to 9-month-old infants, examine the sequelae of infant hyperopia, and test whether early partial spectacle correction improved visual outcome (strabismus and acuity). The second program also examined whether infant hyperopia was associated with developmental differences across various domains such as language, cognition, attention, and visuomotor competences up to age 7 years. Linked programs in six European countries assessed costs of infant refractive screening.

METHOD

In the first program, screening included an orthoptic examination and isotropic photorefraction, with cycloplegia. In the second program we carried out the same screening procedure without cycloplegia. Hyperopic infants (> or = +4 D) were followed up alongside an emmetropic control group, with visual and developmental measures up to age 7 years, and entered a controlled trial of partial spectacle correction.

RESULTS

The second program showed that accommodative lag during photorefraction with a target at 75 cm (focus > or = +1.5 D) was a marker for significant hyperopia. In each program, prevalence of significant hyperopia at 9 to 11 months was around 5%; manifest strabismus was 0.3% at 9 months and 1.5 to 2.0% by school age. Infant hyperopia was associated with increased strabismus and poor acuity at 4 years. Spectacle wear by infant hyperopes produced better visual outcome than in uncorrected infants, although an improvement in strabismus was found in the first program only. The corrections did not affect emmetropization to 3.5 years; however, both corrected and uncorrected groups remained more hyperopic than controls in the preschool years. The hyperopic group showed poorer overall performance than controls between 1 and 7 years on visuoperceptual, cognitive, motor, and attention tests, but showed no consistent differences in early language or phonological awareness. Relative cost estimates suggest that refractive screening programs can detect visual problems in infancy at lower overall cost than surveillance in primary care.

CONCLUSIONS

Photo/videorefraction can successfully screen infants for refractive errors, with visual outcomes improved through early refractive correction. Infant hyperopia is associated with mild delays across many aspects of visuocognitive and visuomotor development. These studies raise the possibility that infant refractive screening can identify not only visual problems, but also potential developmental and learning difficulties.

Hyperopia and educational attainment in a primary school cohort

BACKGROUND

Vision screening addresses the visual impairments that impact on child development. Tests of long-sightedness are not found in most school screening programmes. The evidence linking mild-moderate hyperopia and lack of progress in school is insufficient, although strengthened by recent findings of developmental problems in infants.

AIMS

To report on the relation between hyperopia and education test results in a cohort of primary school children.

METHODS

A total of 1298 children, aged 8 years, were screened for hyperopia on the basis of fogging test results. School test results (NFER and SATs) were compared between groups categorised by referral status and refractive error.

RESULTS

A total of 166 (12.8%) fogging test failures were referred for ophthalmic assessment. Ophthalmic tests on 105 children provided an accurate diagnosis of vision defects, for reference to their education scores. Fifty per cent of the children examined by optometrists required an intervention (prescription change, glasses prescribed, or referral). Mean (95% CI) NFER scores of children with refractive errors (summed for both eyes) >+3D (98.4, 93.0-103.8, n = 32) or >+1.25D (best eye) (99.3, 93.0-105.6, n = 26) were lower than the respective scores of children with a less positive refractive state (104.8, 100.7-108.9, n = 43) (103.6, 99.7-107.4, n = 49), the non-referred group, and total sample. The SATs results followed a similar trend. A high proportion of the fogging test failures (16%) and confirmed hyperopes (29%) had been referred to an educational psychologist, and the latter group contributed substantially to the poor education scores.

CONCLUSIONS

The results of this study provide further evidence for a link between hyperopia and impaired literacy standards in children.

Calibration of photoscreeners for single-subject, contact-induced hyperopic anisometropia

BACKGROUND

In 1999, the threshold anisometropic hyperopia for photoscreening toddlers and preschoolers was determined to be 1.50 D. We compared crescent size from induced anisometropic hyperopia using three commercially available photoscreeners and compared them with miniature digital video cameras, which have a flash-to-lens dimension similar to two of the three photoscreeners. Photoscreeners were compared with a remote autorefractor.

METHODS

Anisometropia was induced by placing several known minus contact lenses (-1.00, -1.50, and -2.00 D) in the nondominant eye of a visually healthy, orthophoric emmetrope older than 3 years. Photographs were taken in light and dim conditions with all three cameras with and without the contact lenses. Corneal diameter, pupil diameter, and crescent location were determined. A protocol for flash initiation, focus, and distance was determined for the digital cameras.

RESULTS

Under light and dim ambient light, no camera yielded a significant hyperopic crescent for emmetropia (no contact lens) or induced 1.0-D anisometropia. We propose a simple measure, "delta center crescent" distance from the center of the pupil to the edge of the crescent. Delta center crescent less than 1.5 mm identified most examples of threshold hyperopic anisometropia. The ideal distance for photoscreening using the digital cameras is approximately 1.6 m, whereas the commercially available photoscreeners focus at 1.0 m.

CONCLUSIONS

We have developed a protocol for photoscreening and its interpretation with a miniature digital video camera weighing 400 g and costing approximately dollar 1,000. Threshold anisometropic hyperopia can be determined from digital still or audio-labeled video flash images if the pupils are at least 4 mm.

Sensitivity of photoscreening to detect high-magnitude amblyogenic factors

PURPOSE

To determine the sensitivity of a unique pupil-size based set of referral criteria of the MTI PhotoScreener(Medical Technology and Innovations, Inc, Cedar Falls, Iowa) to detect high magnitude refractive error.

METHODS

The photoscreening photographs of 949 preschool children previously analyzed were reevaluated with the new referral criteria. The original photographs had been obtained from pediatricians' offices and public health and Women, Infants, and Children's (WIC) clinics. The results of this analysis were compared with the gold standard clinical examination and cycloplegic refraction. Sensitivities were calculated for amblyogenic factors based on the magnitude of the refractive error.

RESULTS

For 26 patients with anisometropia, the sensitivity to detect anisometropia increased from 46% for +1.25 or greater spherical interocular difference to 100% for +2.50 spherical intraocular difference. For 36 patients with hypermetropia in at least 1 meridian ranging from +3.75 to +7.50 D, sensitivity increased from 53% to detect +3.75 D or greater to 70% for +5.00 D or greater. The sensitivity to detect hypermetropia of +5.75 D or greater was 100%. These criteria detected 82% of patients with astigmatism greater than or equal to +3.00 D, and 100% of patients with astigmatism greater than +3.50 D.

CONCLUSION

It is crucial that screening programs avoid over-referrals caused by high false-positive screening rates. The sensitivity of our new criteria increases with higher magnitude refractive error; patients with moderate and severe amblyogenic factors are almost never missed. While the sensitivity to detect lower magnitude refractive error is poor, the amblyogenic impact of such errors remains to be determined.

Amblyopia: detection, prevention, and rehabilitation

This year's literature on the detection, prevention, and rehabilitation of amblyopia is again somewhat dominated by the topic of vision screening, specifically photoscreening and also by the therapeutic challenges of compliance and late treatment. Basic scientists also have added to our knowledge and understanding of certain interesting and clinically significant characteristics of the visual perception of amblyopes.