Relative Proportion Of Different Types Of Refractive Errors In Subjects Seeking Laser Vision Correction

Ocular residual astigmatism (ORA) does not seem to correlate with baseline refractive error among refractive surgery candidates

PURPOSE

Ocular residual astigmatism (ORA) is defined as the difference between refractive astigmatism and anterior corneal astigmatism. A high ORA may be correlated with poorer results in patients undergoing corneal-based laser surgery. Is a high baseline refractive error related to a higher degree of ORA?

METHODS

This was a retrospective analytical study including 181 right eyes of an equal number of refractive surgery candidates. Manifest subjective refraction was measured, along with a Pentacam AXL Wave corneal tomography. Via a vector analysis with this methodology, subjective cylinder was translated into the corneal plane and a vectorial subtraction was performed in order to measure ORA. Spearman's rank order test, one-way ANOVA and Chi-square were used to determine whether different levels of baseline refractive error correlate with different levels of ORA.

RESULTS

Mean age was 28.33 ± 4.71 years with a female preponderance (65.7%). Mean ORA was 0.74 ± 0.39 D, with 33.1% of eyes having an ORA ≥ 0.90 D. There was not a correlation between ORA and level of myopia (rho = - 0.022; p = 0.764), nor between ORA and spherical equivalent (rho = 0.009; p = 0.903). Refractive astigmatism did not demonstrate to be correlated with ORA level either (rho = 0.078; p = 0.329). One-way ANOVA tests failed to demonstrate an association between different classifications of refractive error and level of ORA.

CONCLUSIONS

In the studied population, ORA is not correlated with baseline refractive error. Every patient presenting for possible corneal-based laser refractive surgery should be evaluated for a possible high level of ORA, irrespective of their baseline ametropia level.

Multimodal Deep Learning Classifier for Primary Open Angle Glaucoma Diagnosis Using Wide-Field Optic Nerve Head Cube Scans in Eyes With and Without High Myopia

PRCIS

An optical coherence tomography (OCT)-based multimodal deep learning (DL) classification model, including texture information, is introduced that outperforms single-modal models and multimodal models without texture information for glaucoma diagnosis in eyes with and without high myopia.

BACKGROUND/AIMS

To evaluate the diagnostic accuracy of a multimodal DL classifier using wide OCT optic nerve head cube scans in eyes with and without axial high myopia.

MATERIALS AND METHODS

Three hundred seventy-one primary open angle glaucoma (POAG) eyes and 86 healthy eyes, all without axial high myopia [axial length (AL) ≤ 26 mm] and 92 POAG eyes and 44 healthy eyes, all with axial high myopia (AL > 26 mm) were included. The multimodal DL classifier combined features of 3 individual VGG-16 models: (1) texture-based en face image, (2) retinal nerve fiber layer (RNFL) thickness map image, and (3) confocal scanning laser ophthalmoscope (cSLO) image. Age, AL, and disc area adjusted area under the receiver operating curves were used to compare model accuracy.

RESULTS

Adjusted area under the receiver operating curve for the multimodal DL model was 0.91 (95% CI = 0.87, 0.95). This value was significantly higher than the values of individual models [0.83 (0.79, 0.86) for texture-based en face image; 0.84 (0.81, 0.87) for RNFL thickness map; and 0.68 (0.61, 0.74) for cSLO image; all P ≤ 0.05]. Using only highly myopic eyes, the multimodal DL model showed significantly higher diagnostic accuracy [0.89 (0.86, 0.92)] compared with texture en face image [0.83 (0.78, 0.85)], RNFL [0.85 (0.81, 0.86)] and cSLO image models [0.69 (0.63, 0.76)] (all P ≤ 0.05).

CONCLUSIONS

Combining OCT-based RNFL thickness maps with texture-based en face images showed a better ability to discriminate between healthy and POAG than thickness maps alone, particularly in high axial myopic eyes.

STATIS multivariate three-way method for evaluating quality of life after corneal surgery: Methodology and case study in Costa Rica

Vision-related quality of life (QoL) analyzes the visual function concerning individual well-being based on activity and social participation. Because QoL is a multivariate construct, a multivariate statistical method must be used to analyze this construct. In this paper, we present a methodology based on STATIS multivariate three-way methods to assess the real change in vision-related QoL for myopic patients by comparing their conditions before and after corneal surgery. We conduct a case study in Costa Rica to detect the outcomes of patients referred for myopia that underwent refractive surgery. We consider a descriptive, observational and prospective study. We utilize the NEI VFQ-25 instrument to measure the vision-related QoL in five different stages over three months. After applying this instrument/questionnaire, a statistically significant difference was detected between the perceived QoL levels. In addition, strong correlations were identified with highly similar structures ranging from 0.857 to 0.940. The application of the dual STATIS method found the non-existence of reconceptualization in myopic patients, but a statistically significant recalibration was identified. Furthermore, a real change was observed in all patients after surgery. This finding has not been stated previously due to the limitations of the existing statistical tools. We demonstrated that dual STATIS is a multivariate method capable of evaluating vision-related QoL data and detecting changes in recalibration and reconceptualization.

Status of eye health among tribal school children in South India

Purpose:

Global trends show a high prevalence of refractive errors among children. The prevalence of vision impairment due to uncorrected refractive errors among school children is increasing and the need for management of other ocular conditions is also reported. This study presents the status of eye health and pattern of daily activities among the school children of a tribal location in Tamil Nadu, South India.

Methods:

A cross-sectional study was conducted in 13 schools of Karumandurai cluster, Salem district in Tamil Nadu, India. A three-phased comprehensive school screening protocol was conducted to understand the prevalence of vision impairment, refractive error, and other ocular conditions along with a survey about the daily activities of the children at school and home.

Results:

Among the 3655 children screened, the prevalence of vision impairment was found to be 0.62% (n = 23, 95% confidence interval [CI] 0.42–0.94) and prevalence of refractive error was 0.30% (n = 11, 95%CI 0.17–0.54), among which 0.11% (n = 4) were already wearing spectacles. A total of 44 children (1.20%; 95%CI 0.90–1.61) were found to have other ocular problems and among them, 14 (0.38%) had visual acuity less than 20/30 (6/9). Almost 84% of children required surgical or specialty eye care services. Vision impairment was more in children with other ocular conditions compared to refractive errors (P < 0.001).

Conclusion:

The prevalence of vision impairment and refractive errors in this tribal area was less. Ocular conditions were more prevalent than refractive errors in this tribal region with the majority of children needing specialty or surgical eye care services. This implies the need for access to secondary or tertiary eye care centers.

Rural-urban differences in myopia prevalence among myopes presenting to Bhutanese retinal clinical services: a 3-year national study

PURPOSE

To determine the prevalence and demographic characteristics of myopia among patients presenting to the national vitreo-retinal (VR) services in Bhutan.

METHODS

The records of the VR clinic at the apex national referral centre, providing the only VR services in the country, were reviewed to identify all new myopia patients over three years. Thus, we surveyed all referrals nationally. The patients were categorised into urban and rural females and males. We assessed myopia prevalence in each group by occupational and educational categories. We examined univariate prevalence data and a multivariate logistic regression (MLR) identified independent factors.

RESULTS

Of 2913 cases 1544 (53.0%) were males. Females presented earlier (mean ±SD): overall 45.7 ± 21.9 cf. 48.6 ± 21.6 years, p = 0.003, and among myopes 23.9 ± 13.5 cf. 27.6 ± 18.6 years, p = 0.032. Myopia constituted 92.1% of refractive error, an overall prevalence of 12.3%. Myopia was more common among females (p = 0.01) and urbanites (p = 0.02). Myopia prevalence was highest among urban females (20.9%), followed by urban males (11.9%), rural females (6.8%), and rural males (5.2%). Logistic regression revealed that the odds of having myopia were increased by being a student (4.96 ×) or professional (1.96 ×), and decreased by rural living (1.75 ×), all p ≤ 0.038.

CONCLUSIONS

This is the first study on myopia in Bhutan. As observed throughout East and Southeast Asia, the prevalence of myopia was higher in females and urbanites and positively associated with formal education. Given known risk factors, these prevalences may be driven by educational pressures and reduced time spent outdoors.

Prevalence and pattern of refractive errors among Saudi adults

Background & Objectives:

Refractive Errors (RE) are responsible for major portion of the treatable visual impairment and avoidable blindness in the world. The prevalence of RE varies with age, gender, ethnicity, geographical locations and also from time to time due to progresse in eye care services. We aimed to study the prevalence of RE and assess their patterns among Saudi adults of Arar city, the capital of Northern Border Region of Saudi Arabia.

Methods:

This is a cross-sectional, population-based study. A total number of 966 Saudi adults aged 16 to 39 years were enrolled. The patterns of their RE were studied through auto-refraction evaluation.

Results:

The prevalence of RE was 45.8%. The most frequent type of RE was myopia in 24.4%, followed by hyperopia 11.9% and astigmatism in 9.5% cases. Ages and genders significantly affect the prevalence of the different patterns of RE (0.033 and 0.012, respectively).

Conclusion:

The prevalence of RE in Arar city is slightly lower than that previously published in the same targeted age group. Myopia is the main RE. More awareness programs, especially among young adults are recommended for better outcomes.