Refractive precision in uncomplicated eyes with pseudoexfoliation: three-piece versus one-piece intraocular lens implantation

PURPOSE

To evaluate the refractive precision of three-piece versus one-piece intraocular lenses (IOLs) in eyes with pseudoexfoliation (PXF) and changes in anterior chamber depth (ACD) following cataract surgery.

METHODS

This prospective, nonrandomized, interventional, comparative case series included PXF eyes, which were implanted with one-piece acrylic IOL or three-piece acrylic IOLs (Group A; n = 31, Group B; n = 30). Non-PXF control eyes were implanted with one-piece acrylic IOL (Group C; n = 30). Postoperative refractive error (RE) and absolute RE, as well as pre- to postoperative ACD changes, were statistically analysed. A p value < 0.05 was considered statistically significant.

RESULTS

Changes in ACD (mean ± standard deviation) in Groups A, B and C were 0.9 ± 0.4, 1.0 ± 0.3 and 0.7 ± 0.4 mm, respectively. Significant differences were found between Groups A and C (p = 0.043) and between Groups B and C (p = 0.008). In Groups A, B and C, the median and interquartile (Q1 to Q3) values were 0.3 (-0.8 to 1.0), -0.5 (-0.8 to -0.3) and 0.1 (-0.4 to 0.3) for RE and 1.0 (0.4 to 1.3), 0.5 (0.3 to 0.8) and 0.3 (0.3 to 0.5) for absolute RE, respectively. The RE differences between Group A and B (p = 0.009) and Group B and C (p < 0.001) were statistically significant. For absolute RE, the differences were significant for all comparisons (p < 0.05).

CONCLUSION

Refractive precision in PXF eyes may be better with three-piece than with one-piece IOL implantation, but worse than with one-piece IOL implantation in non-PXF eyes. Significant changes in ACD in PXF eyes may be related to RE.

Retrospective review of Duke men's basketball eye care: annual screenings and traumatic injuries

OBJECTIVES

1) To assess the utility of performing eye screenings for healthy basketball players. 2) To describe the traumatic injuries sustained by competitive college basketball players.

METHODS

The eye screening examinations of the Duke University Men's Basketball players over six seasons were reviewed retrospectively. Traumatic basketball-related eye injuries amongst Duke University Men's Basketball players over 16 seasons were also reviewed and described.

RESULTS

Forty-four total players underwent screening examinations. Thirteen (29.5%) of athletes had uncorrected or under-corrected refractive errors. One athlete was found to have a severe monocular visual deficit secondary to a traumatic injury in childhood, which was significantly mitigated by a contact lens referral. Eight traumatic ocular injuries in eight different athletes, 8.6% of the total roster players in this interval, required ophthalmologic consultation. Most injuries, 7/8, resulted in no permanent visual impairment. However, two severe episodes of injury required operative intervention, and one episode involving a giant retinal dialysis and traumatic optic nerve head avulsion caused severe, permanent visual loss. Most injuries did not result in significant competition time loss, with a median time loss of 5 days (range 0 to 240 days).

CONCLUSION

Screening eye examinations in healthy athletes are beneficial for the identification and treatment of refractive errors. Traumatic basketball-related eye injuries are common and result in a wide array of injuries. Although most basketball-related eye injuries do no result in permanent visual loss, given the potential for severe injury, many basketball-related eye injuries require expert ophthalmic consultation.

Comparison of Longitudinal Changes in Refractive Error of Hyperopic Children with or without Refractive Accommodative Esotropia

We investigated longitudinal changes in the spherical equivalent refractive error (SE) in hyperopic children with or without refractive accommodative esotropia (AccET). A total of 456 patients met the inclusion criteria: 190 (41.7%) in the hyperopic control group and 266 (58.3%) in the AccET group. All patients received at least 3 years of follow-up after spectacle prescription. Subgroups were divided according to age when spectacles were prescribed, presence of amblyopia, or initial SE. Longitudinal changes in SE in children with hyperopia showed a gradual decrease, although SE of younger children with AccET increased over the first 4 years and then decreased thereafter. SE in eye with higher SE was tended to decrease significantly in patient with Acc ET than hyperopic control group (group × time p = 0.015). Amblyopic eyes showed a greater decreased in SE compared with non-amblyopic eyes, but it was not statistically significant (p = 0.07). SE was significantly decreased in children with more hyperopia (≥ 3 D) compared with children with less hyperopia (<3 D) (p = 0.008). Emmetropization of hyperopia was faster in hyperopic patients without AccET and could be affected by the age of the initial spectacles prescription, initial amount of SE, or presence of amblyopia.

Refractive Outcomes in Fuchs' Endothelial Corneal Dystrophy: Conventional and Femtosecond Laser-Assisted Cataract Surgery

Purpose

To investigate the refractive outcomes of eyes with Fuchs’ endothelial corneal dystrophy (FECD) following phacoemulsification.

Methods

This is a retrospective chart review of patients with FECD who underwent phacoemulsification. Manifest refraction at the early postoperative period (1–6 weeks) and late postoperative period (3–12 months) was collected. The spherical equivalent (SE) and variance of SE from target in diopters (D) were analyzed.

Results

A total of 219 eyes from 175 FECD patients (73 FLACS, 146 conventional phacoemulsification) were included. In the early postoperative period, when comparing variance from intended target, 62% (n=126) had a SE variance of ≤0.5 D, 22% (n=44) >0.5 D and ≤1 D, and 17% (n=34) >1 D. In the late postoperative period, 62% (n=85) had a SE variance of ≤0.5 D, 19% (n=26) >0.5 D and ≤1 D, and 20% (n=27) >1 D. There was no difference in the variance of SE comparing FLACS versus conventional phacoemulsification in either the early postoperative period (p=0.78) or the late postoperative period (p=0.29).

Conclusion

Patients with mild-to-moderate FECD had favorable refractive outcomes with phacoemulsification. There was no difference in refractive outcomes in eyes with FECD between the group that underwent FLACS versus the group that underwent conventional phacoemulsification.

Influence of Chronic Ocular Hypertension on Emmetropia: Refractive, Structural and Functional Study in Two Rat Models

Chronic ocular hypertension (OHT) influences on refraction in youth and causes glaucoma in adulthood. However, the origin of the responsible mechanism is unclear. This study analyzes the effect of mild-moderate chronic OHT on refraction and neuroretina (structure and function) in young-adult Long-Evans rats using optical coherence tomography and electroretinography over 24 weeks. Data from 260 eyes were retrospectively analyzed in two cohorts: an ocular normotension (ONT) cohort (<20 mmHg) and an OHT cohort (>20 mmHg), in which OHT was induced either by sclerosing the episcleral veins (ES group) or by injecting microspheres into the anterior chamber. A trend toward emmetropia was found in both cohorts over time, though it was more pronounced in the OHT cohort (p < 0.001), especially in the ES group (p = 0.001) and males. IOP and refraction were negatively correlated at week 24 (p = 0.010). The OHT cohort showed early thickening in outer retinal sectors (p < 0.050) and the retinal nerve fiber layer, which later thinned. Electroretinography demonstrated early supranormal amplitudes and faster latencies that later declined. Chronic OHT accelerates emmetropia in Long–Evans rat eyes towards slowly progressive myopia, with an initial increase in structure and function that reversed over time.

Amber light treatment produces hyperopia in tree shrews

PURPOSE

Exposure to narrow-band red light, which stimulates only the long-wavelength sensitive (LWS) cones, slows axial eye growth and produces hyperopia in tree shrews and macaque monkeys. We asked whether exposure to amber light, which also stimulates only the LWS cones but with a greater effective illuminance than red light, has a similar hyperopia-inducing effect in tree shrews.

METHODS

Starting at 24 ± 1 days of visual experience, 15 tree shrews (dichromatic mammals closely related to primates) received light treatment through amber filters (BPI 500/550 dyed acrylic) either atop the cage (Filter group, n = 8, 300-400 human lux) or fitted into goggles in front of both eyes (Goggle group, n = 7). Non-cycloplegic refractive error and axial ocular dimensions were measured daily. Treatment groups were compared with age-matched animals (Colony group, n = 7) raised in standard colony fluorescent lighting (100-300 lux).

RESULTS

At the start of treatment, mean refractive errors were well-matched across the three groups (p = 0.35). During treatment, the Filter group became progressively more hyperopic with age (p < 0.001). By contrast, the Goggle and Colony groups showed continued normal emmetropization. When the treatment ended, the Filter group exhibited significantly greater hyperopia (mean [SE] = 3.5 [0.6] D) compared with the Goggle (0.2 [0.8] D, p = 0.01) and Colony groups (1.0 [0.2] D, p = 0.01). However, the refractive error in the Goggle group was not different from that in the Colony group (p = 0.35). Changes in the vitreous chamber were consistent with the refractive error changes.

CONCLUSIONS

Exposure to ambient amber light produced substantial hyperopia in the Filter group but had no effect on refractive error in the Goggle group. The lack of effect in the Goggle group could be due to the simultaneous activation of the short-wavelength sensitive (SWS) and LWS cones caused by the scattering of the broad-band light from the periphery of the goggles.

Prevalence of refractive errors among the school-going children in East Sikkim

Purpose:

Vision plays an important role in child's development for learning and communication. Uncorrected refractive error (URE) has become a major challenge to health care policy makers especially in school going children. We aim to report the prevalence of refractive error among the school students of the east district of Sikkim, India.

Methods:

A cross-sectional study was carried out among 15,954 school children under school health program of national program for control of blindness. The screening was conducted in 40 schools of east district which included primary, higher secondary, monastic and private schools.

Results:

The prevalence of refractive error was 6.7% among which myopia was the most common error present in 335 (31.1%) children, followed by astigmatism in 317 (29.4%) and the remaining 29 (2.6%) with hyperopia. The age group between 14-17 years had high prevalence of refractive error (9.2%). Females had slightly higher refractive error (6.93%) than males (5.9 %). Most backward classes were found to be highest suffering from refractive error (26.65%) and the least seen was found in schedule tribe (11.6%).

Conclusion:

The study provides a useful and baseline data about the refractive error amongst the school children of east Sikkim. A larger study needs to be conducted in all the schools of the state to get a clearer picture of RE and other eye related diseases to detect vision problem as early as possible.

Phenotypic Consequences of the GJD2 Risk Genotype in Myopia Development

Purpose

To study the relatively high effect of the refractive error gene GJD2 in human myopia, and to assess its relationship with refractive error, ocular biometry and lifestyle in various age groups.

Methods

The population-based Rotterdam Study (RS), high myopia case-control study MYopia STudy, and the birth-cohort study Generation R were included in this study. Spherical equivalent (SER), axial length (AL), axial length/corneal radius (AL/CR), vitreous depth (VD), and anterior chamber depth (ACD) were measured using standard ophthalmologic procedures. Biometric measurements were compared between GJD2 (rs524952) genotype groups; education and environmental risk score (ERS) were calculated to estimate gene-environment interaction effects, using the Synergy index (SI).

Results

RS adults carrying two risk alleles had a lower SER and longer AL, ACD and VD (AA versus TT, 0.23D vs. 0.70D; 23.79 mm vs. 23.52 mm; 2.72 mm vs. 2.65 mm; 16.12 mm vs. 15.87 mm; all P < 0.001). Children carrying two risk alleles had larger AL/CR at ages 6 and 9 years (2.88 vs. 2.87 and 3.00 vs. 2.96; all P < 0.001). Education and ERS both negatively influenced myopia and the biometric outcomes, but gene-environment interactions did not reach statistical significance (SI 1.25 [95% confidence interval {CI}, 0.85-1.85] and 1.17 [95% CI, 0.55-2.50] in adults and children).

Conclusions

The elongation of the eye caused by the GJD2 risk genotype follows a dose-response pattern already visible at the age of 6 years. These early effects are an example of how a common myopia gene may drive myopia.

Ocular manifestations and refractive errors among people living with HIV in Pune, India: a cross-sectional study

Objective

We aimed to determine the ocular manifestation and refractive error prevalences among people living with HIV (PLHIV) in Pune, India.

Methods

This cross-sectional study included HIV-infected adults attending a National AIDS Research Institute clinic. Ophthalmologic examination included visual acuity estimation, refraction, orthoptic evaluation, slit lamp and fundus examination, and photography.

Results

In total, 441 HIV-infected individuals were enrolled. The participants' median age was 44 (interquartile range 38–49) years and 227 (51.5%) were men. Refractive errors occurred in 132 (29.9%) individuals. Ocular manifestations were present in 93 (21.1%) participants and the most frequent was cataract in 59 (13.4%) participants. Multivariate logistic regression analysis showed that participants who were illiterate (adjusted odds ratio [AOR] 2.80, 95% confidence interval [CI] 1.47–5.33) and those aged greater than 40 years (AOR 5.59, 95% CI 2.69–11.61) were more likely to have ocular manifestations. The odds of having ocular manifestations were greater in participants with treatment substitution or changes (AOR 2.11, 95% CI 1.16–3.82).

Conclusions

Cataract and refractive errors were prevalent among PLHIV. PLHIV should be encouraged to have regular ophthalmic checkups. Individuals with lower education levels and older age should be counseled regarding eye care and timely reporting of ocular symptoms.

Stereoacuity Among Patients with Refractive Error at University of Gondar, Northwest Ethiopia

PURPOSE

This study aimed to assess the level of stereopsis, proportion of poor stereopsis, and factors influencing stereopsis in adults with refractive error.

METHODS

This was a cross-sectional, descriptive study conducted on 153 adults with refractive error at Gondar University Hospital Tertiary Eye Care Center from April 08 to June 07, 2019. Structured questionnaires and ophthalmic instruments (Retinoscope, Worth Four Dot test and TNO Stereo plates) were used to collect the data. Data were entered and analyzed with Statistical Package for Social Sciences (SPSS) version 20. The result was summarized using summary statistics such as mean. Chi-squared test of association was applied between stereopsis and independent variables.

RESULTS

The level of stereopsis after correction of refractive error ranged from 1.89 to 2.65 log arc second. Before correction of refractive error, poor stereopsis was observed in 46.4% of the participants, while after correction, it dropped to 39.8% (CI: 95%: 31.1%-47.8%). Stereopsis after correction had a significant association with age, best visual acuity, type of refractive error, and fusional status at distance with a p value < 0.05.

CONCLUSION

Given refractive error corrected, the mean stereopsis in patients with refractive error was 2.42 log arc second. Proportion of poor stereopsis was noted in 39.8% of the participants corrected for refractive error. Age, best corrected visual acuity, type of refractive error, and fusional status had a significant association with stereopsis. Further studies on stereoacuity on a large scale are recommended.

Knowledge and Attitude of Refractive Error Among Public High School Students in Gondar City

INTRODUCTION

Refractive error (RE) is the main cause of visual impairment and blindness in the world. Lack of knowledge and unfavorable attitude of refractive error can have long-term consequences and dramatic effects in children and adults, such as loss of educational and employment opportunities, loss of economic gain for individuals, families, and societies, and impaired quality of life.

AIM

The aim of this study was to assess the level of knowledge and attitude of refractive error among public high school students in Gondar city, Northwest Ethiopia.

METHODS

A school-based cross-sectional study was conducted on 390 public high school students. Those participants were selected by applying a systematic random sampling technique with an interval of 4. Data were collected using a pre-tested structured questionnaire through face-to-face interviews. The collected data were entered into Epi Info version 7.0 and exported into SPSS version 20 for analysis. Results were described using tables and text.

RESULTS

A total of 390 study participants were included in this study with a 92.4% response rate. The overall proportion of good knowledge and a favorable attitude towards a refractive error were 53.8% and 52.1%, respectively. From the study participants, 38.7%, 41.7%, and 64.1% did not know the definition, the risk factors, and the symptoms of refractive error, respectively. Moreover, about 31.3% of the participants believed that wearing spectacle could damage their eyes, whereas 44.1% of the participants agreed with the need for spectacle correction for young people with RE.

CONCLUSION

The proportion of good knowledge and a favorable attitude towards refractive error among public high school students were fair. We recommended that eye care practitioners be committed to increasing the knowledge and attitude of students towards refractive error through eye health education to reduce visual impairment due to refractive error.

Stakeholders' Perceptions of a School-Based Eye Care Programme in Baltimore, MD

PURPOSE

To explore stakeholders' perceptions of a school-based vision programme (SBVP).

METHODS

We conducted 20 focus groups with 105 parents and teachers at schools in Baltimore, MD, that participated in a SBVP. Facilitators used a semi-structured interview guide to discuss participants' perceptions of the SBVP. Focus groups were audio-recorded, transcribed, and coded using inductive thematic analysis.

RESULTS

Participant perceptions fell into three categories: benefits of school-based eye care, limitations of school-based eye care, and observation of impact. The majority of participants had positive comments about the programme; benefits included convenience (location, time, and cost), the comprehensive nature of the programme, the quality of the eyeglasses and ability to receive replacements, and a positive screening/exam experience. Limitations of programme impact were related to communication and organisation, the time to receive the glasses, missed instructional time, and uncertainty about screenings. Observations of impact included academic and classroom improvements, as well as visual and other health improvements.

CONCLUSION

Parents and teachers reported mostly positive perceptions regarding the SBVP. Their appreciation for the convenience underscores that location, cost, time, and comprehensive services are crucial aspects for implementing a successful programme. To maximize impact, programs must also implement robust communication campaigns that integrate into the schools' workflow to help parents and teachers stay engaged in the process from start to finish.

Axial Length in Patients with Myopia and Interpretation of Pattern Electroretinogram Recordings

Purpose

To assess pattern electroretinogram (PERG) recordings in patients with axial myopia with a special focus on the correct interpretation of findings.

Patients and Methods

Sixty patients divided into three groups according to the spherical equivalent of refractive error (group 1, error −3 D to −6 D; group 2, error > −6 D; and controls, error −1 D to +1 D) were examined. Data for the right eye of every patient were considered in the statistical analysis. All patients had a full ophthalmic examination including the measurement of visual acuity, intraocular pressure, degree of refractive error, axial length, biomicroscopic evaluation of the anterior segment, fundoscopy and PERG. The differences of basic parameters and P50 and N95 amplitudes as well as P50 implicit time between groups were studied. Correlations between P50 and N95 amplitudes and P50 implicit time were axial length and refractive error was established.

Results

The P50 amplitude, N95 amplitude and P50 peak time differed significantly between the groups (P<0.01). No significant differences were found for the N95/P50 ratio. Significantly lower P50 and N95 amplitudes (r=−0.42, P<0.01; r=−0.42, P<0.01) and increased P50 peak time (r=0.64, P<0.01) correlated with elongated axial length. A 1-mm increase in axial length corresponded with a 0.41 µV decrease in the P50 amplitude and 0.55 µV reduction of the N95 amplitude. There was also 1.11 ms increase of P50 wave peak time per 1 mm increase of axial length. Significantly lower amplitudes and longer peak times are associated with increased axial length and increased refractive error.

Conclusion

According to results observed in this study, the correct interpretation of PERG recordings requires the consideration of axial length.

Geographic Variation in Strabismus Pattern Among Pediatric Age Group in Lebanon: A Single-Centre Five-Year Observational Study

Background: Strabismus means ocular misalignment. It is also one of the most prevalent types of amblyopia and the leading cause of pediatric visual impairment.

Objective: This study aims to determine the frequency of different types of strabismus and the associated refractive errors and amblyopia in patients younger than 16 years of age. This study also aims to compare the age at presentation and gender between the geographic locations and between different strabismus types.

Materials and methods: A cross-sectional retrospective study was done using the archives of Beirut Eye and ENT specialist hospital between January 2014 and December 2018. Lebanese pediatric patients aged <16 years having strabismus were included in this study.

Results: There was a total of 787 pediatric patients with strabismus, 62.6% of cases had esotropia (ET) and 30.2% exotropia (XT), with ET/XT: 2.07/1. Mt Lebanon had the highest number of cases, whereas Nabatieh was the only governorate with reversed ET/XT ratio. Most patients were diagnosed at the age of 1-5 years, with ET being the most common diagnosis, while XT was mostly found in patients aged 11-15. Hyperopia was the most common (55.4%) refractive error detected in our cohort of strabismus patients, followed by myopia and simple astigmatism. Amblyopia was found in 18.9% of cases, where Nabatieh had the highest count.

Conclusion: Strabismus pattern was investigated for the first time across Lebanon to shed the light on the crucial role of early ophthalmologic examination, to detect early refractive error and strabismus, and to prevent amblyopia.

Effectiveness of citicoline in pediatric patients with refractive amblyopia in Surabaya, East Java, Indonesia

OBJECTIVES

Amblyopia is a decrease of visual acuity that cannot be attributed to any structural abnormality of the eye or visual system, causing a partial or complete loss of vision due to inadequate stimulation in early life. Citicoline has been reported to improve visual acuity in amblyopic eyes as adjuvant treatment. This study was aimed to determine the effectiveness of citicoline in pediatric patients with refractive amblyopia in ophthalmology daily practices.

METHODS

This was a retrospective-descriptive study with a time limited sampling method. This study was conducted at Surabaya Eye Clinic, East Java, Indonesia, by reviewing medical records for the period of January 2018 to December 2019.

RESULTS

A total of 34 eyes were included in the study with the majority aged five years (41.2%) and six years (35.3%). The severity of amblyopia varied among patients, 21 eyes (61.76%) had mild amblyopia, seven eyes (20.59%) had moderate amblyopia, and two eyes (5.88%) had severe amblyopia. The duration of given therapy also varied, 18 eyes (52.94%) were given 3 months therapy, two eyes were given 4 months therapy, 12 eyes were given 6 months therapy, and two eyes were given 8 months therapy. Citicoline was found effective in mild and moderate amblyopia and for the duration of 3 and 6 months (p<0.05). In others group who did not showed statistically significant improvement was due to inadequate samples but clinically significant improvement was noted.

CONCLUSIONS

Citicoline therapy resulted in a clinically and statistically improvement in refractive amblyopia patients.

Correlation Analysis of Dominant Eye and Refractive Error Between Monozygotic Twins

OBJECTIVE

This study aims to investigate the correlation of dominant eye and refractive error between monozygotic twins.

METHODS

The data of dominant eye and refractive error of 13 pairs of monozygotic twins who were treated at the Optometry Clinic were collected. The paired chi-square test and Kappa consistency test were used to analyze the data of dominant eye between monozygotic twins, while the paired t test and Pearson correlation analysis were adopted to analyze the refractive error data. SPSS version 22.0 software was used to analyze the above statistics.

RESULTS

In the Kappa consistency test of dominant eye between monozygotic twins, Kappa value = 0.451, p = 0.052, p>0.05, and in the paired chi-square test, p = 0.250. In the spherical equivalent paired t test for the right eye of monozygotic twins, t = 1.491 and p = 0.162, while in the spherical equivalent paired t test for the left eye, t = 0.753 and p = 0.466. In the spherical equivalent correlation analysis of monozygotic twins, for the spherical equivalent refraction of the right eye, the Pearson correlation results were r = 0.901 and p = 0.00, and for the spherical equivalent refraction of the left eye, the Pearson correlation results were r = 0.971 and p = 0.00.

CONCLUSION

The difference in the chi-square test of dominant eye is not statistically significant between monozygotic twins, but dominant eye and refractive error are correlated to some extent. It is suggested that heredity may be the main determinant of the dominant eye. There is no difference in refractive error between identical twins which are highly correlated, however.

Can Visual Acuity Be Reliably Measured at Home? Validation of Telemedicine Remote Computerised Visual Acuity Measurements

PURPOSE

The recent pandemic has identified the need for telemedicine assessment of ophthalmology patients. A vital component of such assessment is visual acuity (VA) measurement. The aim of this study was to determine the feasibility and reliability of computerised 'at home' VA measurements using COMPlog software.

METHODS

A Bland Altman method comparison study of worse eye 'in clinic' and 'at home' orthoptist-supervised COMPlog computerised VA measurements. Subjects underwent gold standard semi-automated computerised test and retest logMAR VA measurements on their habitually corrected worse eye both 'in clinic' and 'at home.' The orthoptist ran the test from the eye clinic with the patient viewing a secondary PC monitor either in the same clinic room or at home. A screen sharing voice and video conferencing application and standard consumer IT hardware were employed to present the test optotypes in the patient's home.

RESULTS

23 paediatric and 13 adult patients with a range of ocular diseases and worse eye visual acuities were included (range -0.14 to 1.06 logMAR). No significant bias was found between 'in clinic' and 'at home' measurements (mean -0.01 logMAR and 95% confidence interval -0.03, 0.00 logMAR). Test-retest variability of 'in clinic,' 'at home' and 'in clinic' versus 'at home' measurements were within normal reported ranges at 0.12 logMAR (6 ETDRS letters) or less.

CONCLUSION

Remote home VA testing performed by an eye care professional using a semi-automated VA measurement program and video conferencing application provided unbiased measurements with acceptable test-retest reliability. Home testing was both feasible and acceptably reliable in appropriately equipped patients.

Behavioural Features of Cerebral Visual Impairment Are Common in Children With Down Syndrome

It is widely recognised that children with Down syndrome have a broad range and a high prevalence of visual deficits and it has been suggested that those with Down syndrome are more likely to exhibit visual perception deficits indicative of cerebral visual impairment. This exploratory study aims to determine the prevalence of behavioural features suggestive of cerebral visual impairment (CVI) occurring with Down syndrome and whether the visual problems can be ascribed to optometric factors. A cohort of 226 families of children with Down syndrome (trisomy 21), aged 4–17, were invited to participate in a validated question inventory, to recognise visual perception issues. The clinical records of the participants were then reviewed retrospectively. A five-question screening instrument was used to indicate suspected CVI. The majority of the 81 families who responded to the questionnaire reported some level of visual perceptual difficulty in their child. Among this cohort, the prevalence of suspected CVI as indicated by the screening questionnaire was 38%. Only ametropia was found to have a significant association with suspected CVI, although this increased the correct prediction of suspected CVI outcome by only a small amount. Results suggest that children with Down syndrome are more likely to experience problems consistent with cerebral visual impairment, and that these may originate from a similar brain dysfunction to that which contributes to high levels of ametropia and failure to emmetropise. It is important that behavioural features of CVI are recognised in children with Down syndrome, further investigations initiated and appropriate management applied.

Refractive Error and Visual Impairment Among School Children: Result of a South-Eastern Nigerian Regional Survey

PURPOSE

To determine the prevalence refractive errors and causes of visual impairment in school children in the south-eastern region of Nigeria.

METHODS

School-based cross-sectional samples of children 5 to 15 of age in both urban and rural areas were profiled through cluster sampling. The main outcome measures were presenting, uncorrected, and best-corrected visual acuity using the Refractive Error in School-age Children (RESC) protocol.

RESULTS

A total of 5723 children were examined during the study period comprising 2686 (46.9%) males and 3037 (53.1%) females; (M:F ratio 0.9:1) and aged 10.49±2.74SD of mean (range, 5 to 15 years). The age group 12 to <13 accounted for the highest 776 (13.6%) number of the study participants. The uncorrected visual acuity (VA) of <20/40 (6/12) was seen in 188 (3.4%) of the study participants while the presenting and best-corrected visual acuity of <20/40 (6/12) were noted in 182 (3.4%) children and 14 (0.2%) children, respectively. Refractive error was the principal cause of visual impairment.

CONCLUSION

Prevalence of refractive error is low. Myopia is the principal cause of refractive error occurring more in females and in urban schools. The main cause of visual impairment is refractive error, and most children that need spectacle correction did not have them. Program to identify children with refractive error in addition to providing free or affordable optical services remains the key to preventing visual impairment from refractive error particularly in resource-poor settings.

Long-term longitudinal changes in axial length in the Caucasian myopic and hyperopic population with a phakic intraocular lens

Purpose

To determine the long‐term longitudinal axial length changes in myopic and hyperopic adults with an iris‐fixated phakic intraocular lens (pIOL).

Methods

The medical records of patients aged ≥18 years with myopia or hyperopia who were treated with pIOL implantation between 1996 and 2011 for refractive correction with a minimum follow‐up of 5 years after pIOL implantation were analyzed. The main outcome measure was change in ocular axial length over time.

Results

149 eyes of 149 myopic patients and 27 hyperopic eyes of 27 patients were included in this study. Mean patient age was 37.1 ± 10.4 years (35% male) in the myopic group and 39.4 ± 9.4 years (4% male) in the hyperopic group. The eyes of the myopic patients showed a significant mean increase in axial length of 0.45 ± 0.61 mm after a mean follow‐up time of 144 ± 38 months (p < 0.001). In 26 eyes (17%), the axial length had increased by ≥1 mm. The mean annual axial length increase was 0.04 ± 0.06 mm. Axial elongation was associated with a higher degree of myopia (p < 0.001) and younger age (p = 0.02). The eyes of the hyperopic patients showed no change in axial length over time.

Conclusions

Myopic eyes corrected with an iris‐fixated pIOL show continuous increase in axial length at an adult age. Although this study is limited to subjects with a pIOL, this is the first time myopization in Caucasian adults has been reported in a large long‐term longitudinal study.

Electroretinography and Gene Expression Measures Implicate Phototransduction and Metabolic Shifts in Chick Myopia and Hyperopia Models

The Retinal Ion-Driven Fluid Efflux (RIDE) model theorizes that phototransduction-driven changes in trans-retinal ion and fluid transport underlie the development of myopia (short-sightedness). In support of this model, previous functional studies have identified the attenuation of outer retinal contributions to the global flash electroretinogram (gfERG) following weeks of myopia induction in chicks, while discovery-driven transcriptome studies have identified changes to the expression of ATP-driven ion transport and mitochondrial metabolism genes in the retina/RPE/choroid at the mid- to late-induction time-points. Less is known about the early time-points despite biometric analyses demonstrating changes in eye growth by 3 h in the chick lens defocus model. Thus, the present study compared gfERG and transcriptome profiles between 3 h and 3 days of negative lens-induced myopia and positive lens-induced hyperopia in chicks. Photoreceptor (a-wave and d-wave) and bipolar (b-wave and late-stage d-wave) cell responses were suppressed following negative lens-wear, particularly at the 3–4 h and 3-day time-points when active shifts in the rate of ocular growth were expected. Transcriptome measures revealed the up-regulation of oxidative phosphorylation genes following 6 h of negative lens-wear, concordant with previous reports at 2 days in this model. Signal transduction pathways, with core genes involved in glutamate and G-protein coupled receptor signalling, were down-regulated at 6 h. These findings contribute to a growing body of evidence for the dysregulation of phototransduction and mitochondrial metabolism in animal models of myopia.

The Role of Anterior Chamber Depth on Post-operative Refractive Error After Phacovitrectomy

Purpose

To investigate the effect of phacovitrectomy on the post-operative anterior chamber depth (ACD) and refractive outcomes, and to analyze the potential differences between vitreous filling with BSS, air and gas.

Methods

Patients who underwent phacovitrectomy were included in this study and invited for repeated post-operative examination including refraction and biometry at least 3 months after the surgery. Data retrieved included demographic information, indication for phacovitrectomy, surgical details, type of vitreous filling (BSS, air or gas), pre-operative and post-operative biometric data including K-readings, axial length (AL), and ACD, as well as spherical equivalent (SE) values of the target and final refraction.

Results

Forty-three eyes of 43 patients were included in this study, including 10 eyes filled with BSS, 18 with air and 15 with gas. The mean difference between the final measured spherical equivalent (SE) and the SE of the intended target refraction was 0.61±0.68 D (p = 0.019). Only 58.1% of eyes had a final SE within ±0.5D of the target refraction. Following surgery, AL remained unchanged, while mean pre-operative ACD increased significantly from 3.11±0.34 mm to 4.77±0.47 mm (p < 0.001). There was no difference in refractive error between the vitreous fillings and no correlation with AL or ACD.

Conclusions

Phacovitrectomy is associated with lower accuracy of post-operative refraction compared to cataract surgery. This may be attributed to a significant change in ACD, influencing the effective lens position of the IOL, and may require adjustment of the pre-operative calculations.

Strabismus prevalence and associated factors among pediatric patients in southern Ethiopia: a cross-sectional study

Objective

To assess the strabismus prevalence and associated factors among children aged ≤15 years.

Methods

This hospital-based cross-sectional study was conducted from March 2017 to October 2017 in the Department of Ophthalmology & Optometry, Hawassa University Comprehensive Specialized Hospital. Interviewer-administered questionnaires were used to collect relevant data and clinical examinations were performed for patient diagnosis.

Results

Overall, 582 children participated in the study (response rate, 97%). The prevalence of childhood strabismus was 17.9% [95% confidence interval: 14.6–21.1]. Additionally, 9.6%, 16.7%, and 9.6% of the children had anisometropia, amblyopia, and dense cataract, respectively. Among the 16.7% of children with amblyopia, 56.7% had strabismus; among the 22.5% of children with clinically significant refractive error, 52.7% had strabismus. Moreover, among the 9.6% of children with anisometropia, 58.9% had strabismus. The presence of amblyopia (adjusted odds ratio [95% confidence interval]: 3.9, 1.7–8.6), age <5 years (13.5 [5.0–36.1]), age 5 to 10 years (6.1 [2.3–16.3]), and clinically significant refractive error (13.3 [5.8–30.6]) were significantly associated with childhood strabismus.

Conclusions

The prevalence of strabismus was relatively high among patients in this study. Early screening for childhood strabismus is essential. A well-controlled community-based study is needed to confirm strabismus prevalence and predictors.

Myopia, or near-sightedness, is associated with delayed melatonin circadian timing and lower melatonin output in young adult humans

STUDY OBJECTIVES

Myopia, or near-sightedness, is the most common refractive vision disorder and predisposes the eye to many blinding conditions in adulthood. Recent research has suggested that myopia is associated with increased endogenous melatonin production. Here we investigated the differences in melatonin circadian timing and output in young adult myopes and non-myopes (or emmetropes) as a pathogenesis for myopia.

METHODS

A total of 18 myopic (refractive error [mean ± standard deviation] -4.89 ± 2.16 dioptres) and 14 emmetropic participants (-0.09 ± 0.13 dioptres), aged 22.06 ± 2.35 years were recruited. Circadian timing was assessed using salivary dim light melatonin onset (DLMO), collected half-hourly for 7 h, beginning 5 h before and finishing 2 h after individual average sleep onset in a sleep laboratory. Total melatonin production was assessed via aMT6s levels from urine voids collected from 06:00 pm and until wake-up time the following morning. Objective measures of sleep timing were acquired a week prior to the sleep laboratory visit using an actigraphy device.

RESULTS

Myopes (22:19 ± 1.8 h) exhibited a DLMO phase-delay of 1 hr 12 min compared with emmetropes (21:07 ± 1.4 h), p = 0.026, d = 0.73. Urinary aMT6s melatonin levels were significantly lower among myopes (29.17 ± 18.67) than emmetropes (42.51 ± 23.97, p = 0.04, d = 0.63). Myopes also had a significant delay in sleep onset, greater sleep onset latency, shorter sleep duration, and more evening-type diurnal preference than emmetropes (all p < 0.05).

CONCLUSIONS

These findings suggest a potential association between circadian rhythms and myopia in humans.

The effects of peripheral anterior synechiae on refractive outcomes after cataract surgery in eyes with primary angle-closure disease

Objective of the study was to investigate the effects of peripheral anterior synechiae (PAS) on refractive outcomes after cataract surgery in eyes with primary angle-closure disease (PACD).This is a retrospective, cross-sectional study. Seventy eyes of 70 PACD patients who underwent phacoemulsification and intraocular lens implantation. Patients were divided into 2 groups based on the presence of PAS on preoperative gonioscopy. The predictive power of the intraocular lens was calculated by the SRK/T, Hoffer Q, Haigis, and Holladay formulae. The mean absolute error (MAE) and predicted refractive errors were compared between PAS (+) and PAS (-) groups. We also evaluated the refractive errors with regards to the extent of PAS in the subanalyses.The mean MAE was greater in the PAS (+) group with all formulae (0.61-0.70 diopters [D] vs 0.33-0.45 D, all P < .05). The eyes with PAS tended towards myopia (-0.30 D to -0.51 D vs -0.05 D to +0.24 D, all P < .05). However, the MAEs or predicted refractive errors were not different, irrespective of the extent of PAS in the subanalyses (all, P > .05).The presence or absence of PAS may influence the postoperative refractive outcomes in PACD patients.