Journal of Optometry最新文献

Purpose

The intrinsically photosensitive retinal ganglion cells (ipRGCs) regulate pupil size and circadian rhythms. Stimulation of the ipRGCs using short-wavelength blue light causes a sustained pupil constriction known as the post-illumination pupil response (PIPR). Here we examined the effects of ipRGC stimulation on axial length changes to imposed optical defocus in young adults.

Materials and methods

Nearly emmetropic young participants were given either myopic (+3 D, n = 16) or hyperopic (-3 D, n = 17) defocus in their right eye for 2 h. Before and after defocus, a series of axial length measurements for up to 180 s were performed in the right eye using the IOL Master following exposure to 5 s red (625 nm, 3.74 × 10¹⁴ photons/cm²/s) and blue (470 nm, 3.29 × 10¹⁴ photons/cm²/s) stimuli. The pupil measurements were collected from the left eye to track the ipRGC activity. The 6 s and 30 s PIPR, early and late area under the curve (AUC), and time to return to baseline were calculated.

Results

The PIPR with blue light was significantly stronger after 2 h of hyperopic defocus as indicated by a lower 6 and 30 s PIPR and a larger early and late AUC (all p<0.05). Short-wavelength ipRGC stimulation also significantly exaggerated the ocular response to hyperopic defocus, causing a significantly greater increase in axial length than that resulting from the hyperopic defocus alone (p = 0.017). Neither wavelength had any effect on axial length with myopic defocus.

Conclusions

These findings suggest an interaction between myopiagenic hyperopic defocus and ipRGC signaling.

Purpose

Low birth weight (BW) is associated with increased corneal aberrations in childhood and alterations of corneal geometry in adulthood. Increased corneal aberrations may be a factor contributing to decreased visual function in former low BW newborns in later life. Hence, the aim of this study was to analyze the long-term effect of low BW on corneal aberrations in adulthood.

Methods

In the German population-based Gutenberg Health Study (GHS) participants (age: 40–80 years) were examined with Scheimpflug imaging (Pentacam HR, Oculus Optikgeräte GmbH, Wetzlar, Germany). The relationship between self-reported BW and the different types of corneal aberrations was analyzed using linear regression analysis as uni- and multivariable analysis with adjustment for potential confounders. The main outcome measures were corneal aberrations defined as astigmatism (Z₂⁻²; Z₂²), coma (Z₃⁻¹; Z₃¹), trefoil (Z₃⁻³; Z₃³), spherical aberration (Z₄⁰) and root-mean square of higher order aberrations (HOA; 3rd up to 8th order; aperture size: 6 mm).

Results

Overall, 5,628 participants were included in this analysis (3,004 women, aged 56.0 +/- 10.3 years). In a multivariable analysis lower BW was associated with decreased horizontal trefoil (B = 0.004 [0.001; 0.006] µm/500 g; p=.008); higher spherical aberrations (B=-0.006 [-0.008;-0.003] µm/500 g; p<.001), higher RMS (B=-0.028 [-0.042;-0.014] µm/500 g; p<.001), increased HOA (B=-0.007 [-0.010;-0.003] µm/500 g; p<.001) and increased LOA (B=-0.027 [-0.041;-0.013] µm/500 g; p<.001). No association was observed between birth weight and the other types of corneal aberrations in multivariable model.

Conclusion

Our results indicate an association between BW and spherical aberration in adults aged 40 to 80 years. This indicates that low BW may have an association with an altered corneal shape development which may affect optical image quality and, hence, visual function.

Background

To evaluate the 12-month refractive and visual outcomes of Small Incision Guided Human-cornea Treatment (SmartSight®, SCHWIND eye-tech-solutions, Kleinostheim, Germany) in the treatment of myopia corrections with low to moderate astigmatism with the use of a new femtosecond laser system.

Methods

221 eyes of 114 patients consecutively treated with SmartSight lenticule extraction were assessed. The mean age of the patients was 28±6 years at the time of treatment with a mean spherical equivalent refraction of -6.26±2.17D and mean astigmatism of 0.92±0.68D. Monocular corrected distance visual acuity (CDVA), uncorrected distance visual acuity (UDVA) were assessed pre- and post-operatively. Refractive changes have been determined in terms of changes in refraction, as well as changes in keratometric readings. The changes in central epithelial thickness have been determined.

Results

At twelve months post-operatively, mean UDVA was 20/21±2. Spherical equivalent showed a residual refraction of +0.48±0.31D with refractive astigmatism of 0.13±0.18D postoperatively. There was a slight decrease of -0.1 Snellen lines at 12-months follow-up. The same correction was determined using changes in refraction, as well as changes in keratometric readings. The central epithelial thickness increased by +3±2µm. Spherical equivalent correction within ±0.50D was achieved in 199 eyes (90%), and cylindrical correction in 221 (100%). Preoperative corrected distance visual acuity (CDVA) was 20/20 or better in 213 eyes (96%), and postoperative uncorrected (UDVA) was 20/20 or better in 205 eyes (93%). No eye had lost two or more Snellen lines of CDVA.

Conclusions

Myopic astigmatism correction with SmartSight provided good results for efficacy, safety, predictability, and visual outcomes at the twelve months of follow up. The central epithelial thickness barely increased by 3±2µm.

Purpose

The aim of this study was to analyse the postoperative corneal cross-linking results of corneal parameters and the ABCD grading system, depending on the cone location.

Methods

Thirty eyes of 25 patients with keratoconus (KC), who received the corneal cross-linking (CXL) treatment, were included in this study. The exclusion criteria were: patients under 18 years of age, corneal pachymetry less than 400 μm, corneal scarring, history of ocular trauma, history of ocular surgery, and corneal pathology other than KC. Patients were examined at the baseline visit, and followed-up at three, six, and twelve months after the CXL. All patients underwent visual acuity and Scheimpflug tomography at all visits. Progression parameters, keratometries, and ABCD grading were compared between the visits. Patients were classified into two groups: central and paracentral cones group (within the central 5 mm corneal zone) and peripheral cones group (outside the central 5 mm corneal zone), based on X-Y coordinates of maximal keratometry (Kmax).

Results

Parameter A remained relatively stable throughout the follow-up period in both groups. Parameter B and parameter C showed a significant increase in both groups postoperatively. Parameter D showed stability at the 6-month post-CXL visit in the peripheral KC group, while the central and paracentral KC group showed improvement at the 12-month post-CXL visit.

Conclusion

There was no significant difference in the postoperative response between different cone locations in the ABCD grading system, when classifying according to the Kmax, except an earlier recovery of the parameter D in peripherally located cones.

Purpose

The presence of cataract causes reduction in visual acuity (VA) and contrast sensitivity (CS) and thus can affect individual's daily activities. The aim of this study was to investigate self-reported driving difficulty in patients with bilateral cataract.

Methods

A total of 99 participants aged 50 and above, with bilateral cataract, who possessed a valid driving license and drove regularly were chosen for this cross-sectional study that looked into their visual functions (VA and CS) and driving difficulty using the self-reported Driving Difficulty Questionnaire.

Results

The mean age of the participants was 65.04±7.22 years old. Results showed that the mean composite driving difficulty score was 83.18±11.74 and most of the participants were having difficulty for driving in the rain (73.7%) and at night (85.9%). Furthermore, the study found that there was a significant correlation between driving difficulty score and CS (rs = 0.40, p = 0.03). However, there was no significant correlation between driving difficulty score and VA (rs = -0.14, p = 0.17). A linear regression was calculated to predict driving difficulty score based on binocular CS and a significant regression equation was found (F (1,28) = 8.115, p = 0.008) with R² of 0.225. Drivers with bilateral cataract will most likely experience some forms of difficulty, especially when driving under low contrast conditions.

Conclusion

The findings of this study demand that a comprehensive eye examination should be made compulsory for older adult drivers when issuing or renewing their driving license for the safety of all road users.

Objectives

To evaluate the performance of four experimental multifocal gas permeable contact lens (MFGPCL) designs and their impact on visual function in young adults.

Methods

Seventeen young adults (age, 23.17 ± 4.48 years) enrolled in the study. Each participant was randomly assigned to wear two of four MFGPCL designs. They wore the first type of the assigned lens binocularly for one week and, after one week of washout period, wore another design on both eyes for another week. The four MFGPCL designs were as follows: design A (distance zone [DZ] 1.5 mm / add 3.0 D), B (DZ 1.5 mm / add 1.5 D), C (DZ 3.0 mm / add 3.0 D), and D (DZ 3.0 mm / add 1.5 D). Baseline visual acuity, contrast sensitivity function, and accommodation data were collected at baseline and repeated after one week of MFGPCL daily wear.

Results

Distance and near visual acuities were not significant affected with the four MFGPCL designs. Contrast sensitivity was significantly lower in design A across all measured spatial frequencies (p < 0.05), with no significant impact from other designs on all frequencies. No significant effect was observed on accommodation measured at 33 cm (p > 0.05).

Conclusions

Three of the investigated MFGPCL designs preserve satisfactory visual performance. Lens design A incorporated with higher add and smaller center zone diameter had a stronger impact on the visual performance.

Convergence insufficiency (CI) is a common binocular vision (BV) disorder characterized by difficulty in maintaining motor fusion at near, which affects approximately 7.5 percent of the population. Diagnostic criteria for the disorder are inconsistent, ranging from one to many clinical signs. Methodology for clinical tests is inconsistent in measurement technique, visual targets, required repetitions, and normative values.

This manuscript demonstrates the inconsistencies amongst published studies, and highlights the importance of consistent clinical diagnostic signs, measurement techniques, visual targets, and cut-off criteria. For each clinical sign, the recommended methodology for the procedure is described. Several studies do not take age into account when diagnosing CI in their cohorts. As such, the review emphasizes changes in diagnostic signs with age.

This manuscript highlights the need for consistent and clear procedures and diagnostic criteria amongst clinicians and provides the basis for future studies in terms of diagnostic testing required for CI of varying age groups.

Purpose

To determine the prevalence of refractive errors in Jewish and Arab college students in Israel and associations with ethnicity and sex.

Methods

In this retrospective cross-sectional study, first-year college students underwent non-cycloplegic autorefraction and answered a questionnaire to assess age, sex, and self-identified ethnicity. Spherical equivalent refractive error (SER) was calculated, and the prevalence of hyperopia (>+0.50 Diopter, D), emmetropia (>-0.50 to +0.50 D), myopia (≤-0.50D, low ≤-0.50 to >-3.0D, moderate <-3.0 to >-6.0D, high ≤-6.0D), and astigmatism (>0.50D) were determined. Groups were compared using Chi-square or Fisher test. Univariate and multivariate analyses were conducted to identify factors associated with refractive errors.

Results

Participants (n = 807) had a mean age of 22.1 ± 2.6 years (range: 17–30 years) and SER of -1.7 ± 2.2D (range: -13.3 to +5.7D). The prevalence and 95% confidence internal of myopia was 66.3% (63.0–69.6). Jewish students had a higher prevalence than Arab students for myopia (69.2% vs 60.3%), moderate (18.5% vs 12.2%) and high myopia (5.9% vs 1.9%) and astigmatism (51.4% vs 43.9%, p<0.05 for all), but not low myopia or hyperopia. Females had a higher prevalence of myopia than males (68.1% vs 58.7%, p<0.03). Jewish ethnicity was associated with myopia (OR=1.48, p = 0.01) and moderate myopia (OR=1.72, p = 0.01), and studying optometry was associated with moderate myopia (OR=1.63, p = 0.02). Sex and age were not associated with myopia.

Conclusion

Myopia prevalence in Israeli college students is high, showing associations with Jewish, but not Arab, ethnicity, suggesting that ethnic factors may play a role in the refractive differences between Arabs and Jews.

Purpose

Visual search is an active perceptual task influenced by objective factors and subjective factors such as task difficulty, distractors, attention and familiarity respectively. We studied the effect of different search directions, task medium and presence or absence of audio distractors on visual search time in young normal subjects

Methods

Twenty-four young (19–27 years) subjects with normal ocular health (except refractive error) participated in the study after obtaining informed consent. Subjects performed a word search task of ten 7-letter words of medium difficulty level. It was performed by each subject in Up-down, Down-Up, Left-Right, Right-Left, Diagonal and Random directions, with equal number of distractors. The task was performed in paper and digital medium, with or without audio distractors. The conditions were performed in random order by each subject and the time taken to accurately complete the word search was documented for each condition.

Result

The visual search time (VST) was significantly different with different search directions (ANOVA p<0.0001, df=5), considering both digital and non-digital medium, with or without audio distractors. The average VST was the least for left-right search direction (100±7.2 s) and was highest for random search direction (291±19 s), on a digital medium (VST_digital: 183±77 s) and in presence of an audio distractor (VST_audio: 184±77 s). The VST scores were not correlated with the age (r=-0.14, p = 0.25).

Conclusion

The visual search time is significantly delayed for search direction other than left-right direction and in presence of an audio distractor on a digital medium. These factors could play a significant role in visual orientation and specific tasks such as reading.