Oral reading after treatment of dense congenital unilateral cataract

Binocular reading in children following extraction of a dense congenital or infantile unilateral cataract

BACKGROUND

Reading relies on ocular motor function, requiring sequential eye movements (forward and regressive saccades). Binocularly discordant input from a dense congenital or infantile cataract is associated with ocular motor dysfunction and may affect the development of reading ability. The purpose of this study was to assess silent, binocular reading in children treated for unilateral congenital or infantile cataract.

METHODS

Twenty school-age children (age range, 7-13 years) treated for unilateral congenital (n = 9) or infantile (n = 11) cataract and 49 age-similar control children silently read a grade-appropriate paragraph during binocular viewing. Reading rate (words/min) and the number of forward and regressive saccades (per 100 words) were recorded using the ReadAlyzer.

RESULTS

Reading rate in children treated for a unilateral cataract did not differ significantly from controls (174 ± 59 words/min vs 195 ± 54 words/min; P = 0.1). However, they did have significantly more forward saccades (101 ± 33 saccades/100 words vs 87 ± 21 saccades/100 words; P = 0.03) but not regressive saccades (21 ± 14 saccades/100 words vs 16 ± 8 saccades/100 words; P = 0.1) compared with controls. Reading rate was not related to cataract type (congenital vs infantile), visual acuity outcome (poor vs good), or sensory fusion (fail vs pass; all P ≥ 0.1).

CONCLUSIONS

Reading rate of children treated for a dense unilateral cataract did not differ from that of controls. Increased forward saccades during reading may be due to fixation instability associated with fusion maldevelopment nystagmus prevalent in children following cataract extraction.

The Impact of Diplopia on Reading

Aim:

To compare the effect of induced vertical diplopia (small and large separation) on reading speed and accuracy.

Methods:

The Radner Reading Chart (RRC) was used to measure reading speed (correct words per minute (wpm)) and accuracy (percentage). Accuracy was measured using two different methods: ‘accuracy-omission’ where only the omission of a word reduced the score, and ‘accuracy-addition and omission’ where any error reduced the score. Three viewing conditions were created using Fresnel prisms on plano glasses: a control condition without diplopia (6 prism dioptres (Δ) base up (BU) over each eye), small separation vertical diplopia (3Δ BU right eye and 3Δ base down (BD) left eye) and large separation vertical diplopia (6Δ BU right eye and 6Δ BD left eye). Viewing conditions were counterbalanced to minimise order effects.

Results:

Twenty-four participants were included with a mean age of 20.1 years. The mean reading speed in the control condition was 156.90 wpm. Both diplopic conditions significantly reduced the reading speed compared to the control condition, small separation diplopia to 62.75 wpm (p < 0.001) and large separation diplopia to 105.71 wpm (p < 0.001). The mean reading speed with small separation diplopia was significantly slower than the mean reading speed with large separation diplopia (p < 0.01). Median accuracy scores in the control and the large separation diplopia conditions were 100% using both methods of measuring accuracy. The small separation diplopia condition significantly reduced accuracy to 92.86% (accuracy-omission method) and to 57.50% (accuracy-addition and omission method) compared to the control condition (p < 0.01) and the large separation diplopia condition (p < 0.05).

Conclusion:

When vertical diplopia was induced using Fresnel prisms, diplopia of smaller separation resulted in the greatest reduction in reading speed and accuracy, compared to without diplopia and large separation diplopia.

Interocular anatomical and visual functional differences in pediatric patients with unilateral cataracts

Background

Congenital cataracts are often complicated by anterior segment dysgenesis. This study aims to compare bilateral anterior segment parameters, macular thickness, and best-corrected visual acuity (BCVA) in pediatric cataract patients at 3 months after unilateral cataract extraction with intraocular lens implantation.

Methods

Fifty-three pediatric patients with uncomplicated unilateral total cataracts were included. At 3 months post-surgery, bilateral corneal thickness at the thinnest location (CTTL), anterior chamber depth (ACD), and anterior chamber volume (ACV) were measured using Pentacam. Central macular thickness (CMT) was evaluated using spectral-domain optical coherence tomography. BCVA was measured by experienced optometrists concurrently. Descriptive statistics and bivariate corrections were performed to analyze the interocular differences in bilateral anatomic parameters and their relationships with BCVA.

Results

For all 53 included patients (mean age 5.2 ± 2.3 years), the median BCVA was 10/40 in the operated eyes and 40/40 in the contralateral eyes, which indicates a significant interocular difference. BCVA values in the contralateral eyes were significantly correlated with patient age at surgery, but this result differed for BCVA in the operated eyes. The Pentacam analysis revealed no significant interocular differences in bilateral CTTL and ACV, but significant differences were found for ACD.

Conclusions

At 3 months after surgery, unilateral pediatric cataract patients exhibited no significant interocular differences in identified anatomical parameters (except for ACD), and these parameters were not significantly correlated with BCVA in bilateral eyes. Therefore, amblyopia, but not anatomical factors, might be the main cause of interocular visual functional differences in our study population.

Trial registration

ClinicalTrial.gov, NCT02765230, 05/05/2016, retrospectively registered.

Electronic supplementary material

The online version of this article (doi:10.1186/s12886-016-0371-5) contains supplementary material, which is available to authorized users.

Measurement properties of continuous text reading performance tests

PURPOSE

Measurement properties of tests to assess reading acuity or reading performance have not been extensively evaluated. This study aims to provide an overview of the literature on available continuous text reading tests and their measurement properties.

METHODS

A literature search was performed in PubMed, Embase and PsycInfo. Subsequently, information on design and content of reading tests, study design and measurement properties were extracted using consensus-based standards for selection of health measurement instruments. Quality of studies, reading tests and measurement properties were systematically assessed using pre-specified criteria.

RESULTS

From 2334 identified articles, 20 relevant articles were found on measurement properties of three reading tests in various languages: IReST, MNread Reading Test and Radner Reading Charts. All three reading tests scored high on content validity. Reproducibility studies (repeated measurements between different testing sessions) of the IReST and MNread of commercially available reading tests in different languages were missing. The IReST scored best on inter-language comparison, the MNread scored well in repeatability studies (repeated measurements under the same conditions) and the Radner showed good reproducibility in studies.

CONCLUSIONS

Although in daily practice there are other continuous text reading tests available meeting the criteria of this review, measurement properties were described in scientific studies for only three of them. Of the few available studies, the quality and content of study design and methodology used varied. For testing existing reading tests and the development of new ones, for example in other languages, we make several recommendations, including careful description of patient characteristics, use of objective and subjective lighting levels, good control of working distance, documentation of the number of raters and their training, careful documentation of scoring rules and the use of Bland-Altman analyses or similar for reproducibility and repeatability studies.

Deprivation amblyopia and congenital hereditary cataract

Amblyopia is a neurodevelopmental disorder of vision associated with decreased visual acuity, poor or absent stereopsis, and suppression of information from one eye.(1,2) Amblyopia may be caused by strabismus (strabismic amblyopia), refractive error (anisometropic amblyopia), or deprivation from obstructed vision (deprivation amblyopia). 1 In the developed world, amblyopia is the most common cause of childhood visual impairment, 3 which reduces quality of life 4 and also almost doubles the lifetime risk of legal blindness.(5, 6) Successful treatment of amblyopia greatly depends on early detection and treatment of predisposing disorders such as congenital cataract, which is the most common cause of deprivational amblyopia. Understanding the genetic causes of congenital cataract leads to more effective screening tests, early detection and treatment of infants and children who are at high risk for hereditary congenital cataract.