Spectacle Correction Research Articles

Fixation disparity and refractive error among first-year optometry students.

To determine the fixation disparity and refractive error of first-year optometry students to ascertain any relationship between them and also identify any association between fixation disparity and visual symptoms at near. It was an analytical cross-sectional study involving 85 participants aged 17 to 27 years (18.60±1.37), 41% of whom were males. Subjective refraction was done at 3m and fixation disparity was measured with and without spectacle correction using the Wesson Fixation Disparity Card. All analysis was set within a 95% confidence interval with a p-value≤0.05 considered statistically significant. Refractive error ranged from 0.25 SEQ (spherical equivalent) to 5.50 SEQ. Mean fixation disparity ranged from 2.9±2.6 to 3.9±2.8min arc. There was no statistically significant correlation between refractive error and fixation disparity without correction (r=-0.180, p=0.098) and with correction (r=0.155, p=0.157). For fixation disparity in the ortho and exo direction, mean fixation disparity with correction of participants who experienced headaches during or after reading (5.1±2.6min arc) was significantly higher (p=0.032) than participants who did not (2.0±2.6min arc). Myopia is common among first-year optometry students. Refractive error has no significant effect on fixation disparity. Headache is significantly associated with exo fixation disparity at near.

Visual Outcomes Early after Implantable Collamer Lens V4c Implantation in Different Preoperative Spectacle Correction: Full Correction vs. Under Correction

Purpose To investigate visual outcomes early after implantable collamer lens (ICL) V4c implantation between patients with fully corrected and under-corrected spectacles preoperatively. Methods Patients who implanted ICL V4c were divided into the full correction (46 eyes/23 patients) and under-correction groups (48 eyes/24 patients) based on preoperative differences between the spherical diopter of the spectacles and the actual spherical diopter. Refractive outcomes, scotopic pupil size, higher-order aberrations, and subjective visual outcomes as assessed using a validated questionnaire were compared between the two groups 3 months postoperatively. Moreover, the relationships between the severity of haloes and postoperative ocular or ICL parameters were analyzed. Results At the 3-month follow-up, the efficacy indices in the full correction and under-correction groups were 0.99 ± 0.12 and 1.00 ± 0.10, respectively; the safety indices were 1.15 ± 0.16 and 1.15 ± 0.15, respectively. Total-eye spherical aberration (p < 0.0001) and internal spherical aberration (p = 0.0005) were significantly different pre- and post-operatively in the under-correction group, while no differences were found in the full correction group. Total-eye spherical aberration (p = 0.002) and the severity of haloes (p = 0.03) were postoperatively different between the two groups. The severity of haloes was associated with postoperative spherical aberration (total-eye spherical aberration: r = −0.32, p = 0.002; internal spherical aberration: r = −0.24, p = 0.02). Conclusion Good efficacy, safety, predictability, and stability were obtained early after surgery regardless of preoperative spectacle correction. Patients in the under-correction group possessed a shift to negative spherical aberration and reported greater severity of haloes at the 3-month follow-up. Haloes were the most common visual symptoms after ICL V4c implantation and the severity of them was correlated with postoperative spherical aberration.

Interocular Contrast Balancing Partially Improves Stereoacuity in Keratoconus.

Partial improvement in stereoacuity may be achieved by balancing the contrast input to the two eyes of patients with bilaterally asymmetric keratoconus. Interocular differences in image quality, characterized by dissimilar contrast loss and phase shifts, are implicated in stereoacuity loss in keratoconus. This study determined whether contrast balancing improves stereoacuity in this disease condition and, if so, whether it is dependent on the baseline interocular contrast imbalance. Interocular contrast imbalance and stereoacuity of 43 subjects (16 to 33 years) with bilaterally asymmetric keratoconus were tested with spectacle correction as baseline using a binocular rivalry paradigm and random-dot stereograms, respectively. Stereoacuity measurements were repeated in a subset of 33 subjects at their contrast balance point (i.e., contrast level in stronger eye allowing balanced rivalry with 100% contrast in weaker eye) and with contrast levels biased in favor of stronger or weaker eye, all conditions in randomized order. Contrast imbalance level was significantly correlated with the subject's stereoacuity at baseline ( r = -0.47, P = .002). The median (25th to 75th interquartile range) stereoacuity improved by 34.6% (19.0 to 65.1%) from baseline (748.8 arc sec [261.3 to 1257.3 arc sec]) to the contrast balanced condition (419.0 arc sec [86.6 to 868.9 arc sec]) ( P < .001), independent of their baseline stereoacuity or contrast imbalance levels ( r < 0.2, P > .26 for both). Contrast bias in favor of the weaker eye (881.3 arc sec [239.6 to 1707.6 arc sec]) worsened stereoacuity more than a bias toward the stronger eye (502.6 arc sec [181.9 to 1161.4 arc sec]), both relative to the contrast balanced condition ( P < .002). Interocular contrast balancing partially improves stereoacuity in bilaterally asymmetric keratoconus, independent of their baseline contrast imbalance level. Cyclopean viewing may be inherently biased toward the input from the stronger eye in keratoconus.

ASSESSMENT OF THE CORNEAL SURFACE AFTER KERATOREFRACTIVE SURGERY FOR MYOPIA IN PATIENTS PREVIOUSLY USING ORTHOKERATOLOGICAL LENSES

Abstract. Relevance. The results of keratorefractive surgery using Lasik and Femtolasik methods were evaluated inpatients with mild myopia and complex myopic astigmatism. Material and methods. Operations on 20 eyes on the AlconWavelight laser unit were performed. Patients were divided into two groups, the first group — patients who had previously usedorthokeratological night lenses, the second group, who used spectacle correction and soft contact lenses. Results. The stabilityof the result, the state of the surface of the corneal interface were evaluated.

Scheimpflug imaging for evaluation of intraocular lens position in modified flanged scleral fixated intraocular lens.

Scleral fixation of intraocular lens (IOLs) is the most preferred technique for the management of aphakia and the techniques have evolved over the years. These methods have their advantages and disadvantages, however, the major concern being the position of the intraocular lens, its stability and complications. The final IOL position is the major determinant of the final visual acuity, and various imaging modalities have been used to quantify the IOL tilt. Use of Scheimpflug imaging to evaluate the IOL tilt in modified flanged scleral-fixated intraocular lens (MFSIOL). Retrospective chart review of 41 consecutive patients who underwent MFIOL. We conducted a retrospective chart review of 41 consecutive patients who underwent MFIOL. The baseline and final best-corrected visual acuity (BCVA), refractive error, and clinical examination findings were recorded. The vertical and horizontal tilts of the IOLs were calculated using the Scheimpflug image. The IOL tilt (in degrees) in the vertical and horizontal axes was the primary outcome and the BCVA, residual refractive error, intraocular pressure, and surgical complications were secondary outcome measures. The mean baseline BCVA was logMAR 0.49, which improved to logMAR 0.356 (p < .005) after the surgery. The mean IOL tilt in the vertical axis was 3.40° (range of 0.0°-8.5°, interquartile range: 1.21-5.66) and in the horizontal axis was 1.35° (range of 0.60°-4.620°, interquartile range: 0.44-1.86), respectively. There was no correlation between angle of IOL tilt and UCVA (r = 0.089, p = 0.580), BCVA (r = 0.109, p = 0.498), final spherical error (r = 0.081, p = 0.615), cylindrical error (r = 0.207, p = 0.195), axial length (r = 0.105, p = 0.514), and IOL power (r = -0.139, p = 0.388). Modified flanged IOL (MFIOL) is an alternative technique for intrascleral fixation of IOL resulting in good lens stability. The IOL tilt achieved by this technique is minimal and did not influence the final visual outcome or spectacle correction. Scheimpflug imaging is simple and non-invasive method to measure the IOL tilt. This study on 41 eyes was aimed to analyze the lens tilt using Scheimpflug imaging in cases of modified flanged scleral fixation of intraocular lens (MFSFIOL), which is a novel technique to minimize the complications and simplify the procedure. The intraocular lens (IOL) remained stable with an acceptable range of vertical and horizontal tilt. There was no significant effect of IOL tilt on the final best-corrected visual acuity (BCVA) or spectacle correction. Scheimpflug imaging is an accurate and non-invasive technique for assessment of lens position in the patients with intrascleral fixation of IOL.

Subjective Verification of Refraction- A Quality Section Indicator: A Cross-sectional Study

Introduction: Subjective refraction helps in establishing the suitable lens for a patient. But it also needs a patient’s cooperation for the proper estimation of the refractive error. Aim: To determine the impact of counselling of Optometrists on subjective refraction and spectacle prescription to patients attending Ophthalmology Out Patient Department (OPD) at their first visit. Materials and Methods: This was a cross-sectional study conducted for a period of two months from June 2020 to July 2020. All patients attending the OPD at Department of Ophthalmology at R L Jalappa Hospital and Research Centre, Tamaka, Karnataka, India, were included in the study. A total of 120 patients, whose vision was &lt;6/9, were included in each group. Group A, before counselling the Optometrists and Group B, after counselling the Optometrists by systemic random sampling method. The number of patients who required spectacle correction and those who were given spectacle prescriptions at their first visit were identified. The data was analysed using Statistical Package for the Social Sciences (SPSS) version 22.0. Results: In Group A, out of 120 patients only 62 patients (51.7%), had undergone subjective refraction along with spectacle prescription at their first visit. In Group B, (88.3%) 106 patients out of 120, underwent subjective refraction and spectacle correction was given on their first visit. Conclusion: This study shows a clear positive impact of counselling to Optometrists and the importance of counselling in achieving patient’s satisfaction.

Transplantation of the Bowman's layer in combined treatment of recurrent pterygium

The study analyses the technical capability and feasibility for transplantation of the Bowman's layer in the treatment of recurrent pterygium. The transplantation of the Bowmen's layer was performed according to the developed technique on 7 eyes with recurrent pterygium (7 patients aged 34 to 63 years). The combined surgery technique consisted of pterygium resection, laser ablation, autoconjunctival plasty, exposure to a cytostatic drug, non-suture transplantation of the Bowman's layer. Maximum length of the follow-up was 36 months. Analysis involved data from refractometry, visometry (without correction and with spectacle correction), and optical coherence tomography of the retina. There were no complications in any of the studied cases. The cornea and the transplant retained transparency throughout the entire follow-up duration. 36 months after surgery mean spectacle-corrected visual acuity amounted to 0.86±0.2, topographic astigmatism - 1.48±1.4 diopters. Recurrence of pterygium was not observed. All patients were satisfied with the cosmetic outcomes of the treatment. Non-suture transplantation of the Bowmen's layer recovers normal anatomy, physiology and transparency of the cornea after repeat surgical intervention for pterygium. No pterygium recurrences were observed throughout the entire follow-up after treatment with the proposed combined technique.

The Effect of Over Minus Prescription on Negative and Positive Fusional Vergence and Amplitude of Accommodation After Watching Video at Six Meters

Background The purpose of the study was to compare the effects of a -1.00 Dioptre Sphere over minus prescription on negative fusional vergence and positive fusional vergence as well as the amplitude of accommodation in myopic individuals after watching a video at 6 meters.Aim To assess the effect of over-minus lens on the amplitude of accommodation and fusional vergence pre and post-video watching.Methods The study included 30 participants aged between 18 to 25 years who did not have any systemic or ocular-related issues. During the study the participants were given an over-correction of -1.00DS over their existing spectacle correction. They were then instructed to watch a video at a distance of 6 meters for 15 minutes. The amplitude of accommodation as well as negative and positive fusional vergence were measured before and after the 15-minute video-watching session.Results The study results indicate that there was a statistically significant change in the amplitude of accommodation in the right eye when using an over-correction of -1.00DS. However there was no statistically significant change in the fusional vergence with the minus over-correction.Conclusion It is possible that the reduction in the accommodation system observed in the study was caused by wearing the divergence lens which placed the image behind the retina resulting in retinal blur. Prolonged wear of over-minus lenses could also lead to visual fatigue which can disrupt the eye-focusing system. Therefore while prescribing a corrective lens it should be monitored carefully.

Low-vision intervention for oculocutaneous albinism in a Tertiary Eye Care Hospital in India.

The objective of this study on patients with albinism in different age groups was to compare their level of visual impairment with the low-vision intervention (LVI) and its benefit. The medical records of 72 patients with low vision secondary to albinism who were referred to the low vision care clinic from 2015 to 2017 were analyzed. This included the demographic profile such as age, gender, occupation, ocular history, visual acuity status, and type of low-vision device (LVD) preferred. The LVDs prescribed and its subsequent improvement was compared. In this data, 70 (97.2%) people had oculocutaneous albinism and 2 (2.8%) had ocular albinism. Majority of the patients had hyperopic astigmatism 42 (58.3%) and with-the-rule astigmatism 58 (93.5%). Presenting mean visual acuity for distance was noted to be 0.88 logMAR which improved to 0.83 logMAR with the help of spectacle correction. The most commonly prescribed LVD was a dome magnifier for 15 (34.9%) patients. In all the patients, there was statistically significant improvement (P < 0.05) in near vision with the help of LVDs. The study highlights the importance of appropriate LVI for each subdivided age group. Patients with albinism who have received medical and surgical treatment have no or a limited role in restoring useful vision.

Visual satisfaction and spectacle independence with monofocal intraocular lens with enhanced intermediate vision and trifocal intraocular lenses in the prepresbyopic age group patients with cataracts.

This aims to study visual satisfaction and spectacle independence in prepresbyopic age patients with cataracts after the implantation of either monofocal intraocular lens (IOL) with enhanced intermediate vision or trifocal IOL. Private practice. This prospective, observational case study was conducted on patients in the prepresbyopic age group with cataracts. Patients were allocated to one of the two groups. Thirteen patients (26 eyes) received monofocal IOL with enhanced intermediate vision (intermediate vision group), and 12 patients (24 eyes) received diffractive multifocal IOLs (trifocal group). Uncorrected distance visual acuity (UDVA) and corrected distance visual acuity, Uncorrected intermediate visual acuity (UIVA) and uncorrected near visual acuity (UNVA) values, defocus curves, and contrast sensitivities (CS) of the two groups were compared 3 months' postsurgery. Their spectacle independence and visual satisfaction were also assessed. The study patients were aged 35-45 years and comprised 14 males and 11 females. No significant difference was observed in UDVA (intermediate vision group: 0.02 ± 0.01, trifocal group: 0.02 ± 0.01; P = 0.22) and UIVA (intermediate vision group: 0.20 ± 0.10, trifocal group: 0.19 ± 0.10; P = 0.12). However, a statistically significant difference was observed between the groups in terms of UNVA (intermediate vision group: 0.32 ± 0.10, trifocal group: 0.80 ± 0.10; P = 0.01). The mean CS in monofocal IOL with enhanced intermediate vision and trifocal groups were 1.577 ± 0.3 and 1.550 ± 0.2, respectively (P = 0.40). None of the patients experienced photic phenomena. In total, 10 of 13 patients in the monofocal IOL with enhanced intermediate vision group required spectacle correction for near visual acuity in the range of +1.00 to +2.00 D. This study found that there was no significant difference in distance and intermediate vision between the two groups. However, the trifocal group had better uncorrected near vision compared to the monofocal group that had enhanced intermediate vision. The conclusion is that using trifocal IOLs for both eyes provided complete independence from wearing glasses. In addition, no visual disturbances were observed after implanting the new-generation trifocal IOLs.

Non-Diffractive Wavefront-Shaping Intraocular Lens with Extended Depth of Focus: First Implantation Experience

Purpose. Analysis of short-term clinical and functional results of implantation of a new non-diffractive IOL with expanded depth of focus.Patients and methods. The study included 27 patients (35 eyes) after bilateral (8 patients) or monolateral (19 patients) AcrySof IQ Vivity IOL implantation (Alcon, USA) with mean follow-up of 3.8 ± 0.3 (3–5) months. In all cases, IOL implantation was preceded by cataract phacoemulsification or refractive lensectomy. Women accounted for 63 % (n = 17) and men for 37 % (n = 10). AcrySof IQ Vivity DFT015 IOLs were implanted in 24 eyes and toric AcrySof IQ Vivity DFT315, DFT415 and DFT515 IOLs in 11 eyes with clinically significant (more than 1.0 D) astigmatism.Results. There was a significant (p &lt; 0.05) increase in distance and intermediate uncorrected and best corrected visual acuity starting from the 1st day after surgery. An increase from 0.31 ± 0.09 to 0.58 ± 0.12 at the 1st day after the operation, and further up to 0.63 ± 0.13 at the follow-up period of 3 months (p &lt; 0.05) was also registered while assessing near uncorrected visual acuity. In spite of some increase of best corrected near visual acuity in the follow-up period of 3 months in comparison with preoperative period (0.68 ± 0.19 and 0.57 ± 0.16, respectively), these differences were not statisticallysignificant (p &gt; 0.05). After IOL implantation, the spherical refractive index was shown to decrease from –2.75 ± 1.4 in the preoperative period to –0.10 ± 0.73 in the follow-up period of 3 months. Permanent or periodic optical phenomena were detected in 4 patients out of 27 (14.8 %), of them 2 patients (7.4 %) had glare and 2 (7.4 %) — halo. Patients did not complain of difficulties in driving in the dark. In 11 oof 27 cases (40.7 %), patients required spectacle correction for reading. In spite of the need for spectacle correction for near vision in 40 % cases, the vast majority of patients (n = 24; 88.9 %) rated the result of surgery as “excellent” and three (11.1 %) as good.Conclusion. This work presents the first experience in Russia of implantation of a new non-diffractive intraocular lens with an expanded depth of focus forming a wavefront in 35 eyes. The presented data testify to the high efficacy of this IOL for medium distance and far distance vision correction and to the possibility of providing functional near vision. Implantation of the investigated IOL was associated with a low incidence of adverse optical phenomena, such as halo, glare, and discomfort when driving in the dark. The use of this IOL in clinical practice may be an option to achieve the desired outcome in cataract surgery.

Contact correction of postkeratoplastic ametropia in patients after deep anterior lamellar keratoplasty

Purpose. To conduct a clinical and functional analysis of contact correction of postkeratoplastic ametropia with rigid gas-permeable scleral lenses (RGPSL) in patients after deep anterior lamellar keratoplasty.Material and methods. Clinical and functional results of correction of postkeratoplastic ametropia with RGPSL were analyzed on the basis of a comprehensive examination of 35 eyes (35 patients) after deep anterior lamellar keratoplasty (DALK) performed for stage III keratoconus. The examination included patients who had low corrected visual acuity with spectacle correction and the corneal suture was removed 1 year or more after deep anterior lamellar keratoplasty. All patients underwent: autorefractokeratometry, visometry, biomicroscopy, computed keratotopography, aberrometry, endothelial cell density calculation, analysis of corneal graft biomechanical properties, optical coherence tomography of the corneal graft. The mean age of the patients was 29 ± 8 years. In all patients, RGPSL was selected on average 1.5 ± 0.85 years after DALK. All RGPSL were from OKVision (OKV-RGP Onefit Med, Canada). The follow-up period was 6 months.Results. The uncorrected visual acuity was 1.0 ± 1.18 LogMAR, the best corrected visual acuity (BCVA) with glasses was 0.5 ± 0.8 LogMAR, the spherical refractive component was 2.44 ± 2.12 D, the cylindrical refractive component was -6,25 ± 1.24 D. The average value of BCVA in RGPSL increased to 0.72 ± 0.14 (p = 0.0054). The obtained result remained stable during 6 months of observation. In the analysis of corneal aberrations measured with the OPD-Scan II device before and after 6 months after wearing of RGPSL was noted a statistically significant decrease in total corneal aberrations, including higher-order ones. After 6 months of observation, according to Confoscan-4 data was noted the decrease in the density of corneal graft endothelial cells from 2526 ± 332 to 2510 ± 302 cells/mm² (p = 0.0326) and it corresponded to physiological losses.Conclusions. Clinical and functional analysis of the correction of postkeratoplastic ametropia with rigid gas-permeable scleral lenses during 6 months of follow-up showed high optical efficiency and safety of their use during the entire observation period.

Agreement between a mobile applet-based visual acuity self-test program and the conventional method for distance and near visual acuity tests.

To investigate the agreement between a mobile applet-based visual acuity (VA) self-test program and the conventional VA tests. This consecutive case series study included 121 children and adults (242 eyes). Patients were classified into three groups according to age (children, adolescents, and adults). They underwent uncorrected distance visual acuity (UDVA) testing, distance visual acuity with available spectacle correction (DVA with ASC) testing at 2.5-m distance, uncorrected near visual acuity (UNVA) testing, and near visual acuity with available spectacle correction (NVA with ASC) testing at a 0.4-m distance using a mobile applet-based VA self-test program and conventional VA tests in two eyes. Correlations among UDVA, DVA with ASC, UNVA, and NVA with ASC between the two methods were significant in all subjects (all p < 0.001). The intraclass correlation coefficient were 0.960, 0.845, 0.960, and 0.669, respectively (all p < 0.001). The proportions of bias outside the 95% confidence interval limit of agreements were 6.20%, 4.82%, 7.08%, and 6.10%, respectively. There were significant differences in NVA with ASC between the two methods (p < 0.05) in the adolescent group, but no differences in measured parameters were found among children and adult groups. There is good agreement between the mobile applet-based VA self-test program and the conventional VA tests. The VA self-test has good practical value especially in the current pandemic, allowing self-screening of visual acuity, myopia control, and remote management of visual impairment in ocular morbidity.

How straylight affects driving ability

AbstractWe investigated how an increase in straylight affects the driving capacity of young, healthy volunteers between the ages of 20 and 40 years (i.e., people without cataract) in various real‐life driving circumstances using a driving simulator. This simulator allowed us to assess driving behaviour in a controlled, repeatable environment without risk to life or property, while providing a large set of parameters (speed, brake performance, deceleration, collisions, standard deviation of the lateral lane position, (SDLP), headway distance, etc.). The simulator used a fixed‐base setup with a force‐feedback steering wheel, an instrumented dashboard, brake, and accelerator pedals and with a 135° field of view. Participants had to drive along a certain course with of 6 traffic situations (e.g., crossing pedestrian, obstacle on the way, etc…) while wearing their own spectacle correction, both in the presence of a glare source and without. Next this was repeated while wearing a Tiffen Black Pro Mist (BPM) filter in front of their eyes and a glare source. These filters approximate the optical characteristics of cataract fairly well, where BPM 1 mimics simulates early cataract (which often prompts people to stop driving at night) and BPM 2 simulates serious straylight hindrance. Straylight was measured with the van den Berg straylight meter (C‐Quant).The results showed that increased straylight significant alters driving behaviour, such as a decrease in mean, maximum and minimum speed. The detection time and reaction time to an obstacle on the road was significantly longer with increased straylight. Consequently, straylight is an important factor in traffic safety driving conditions, causing altered driving behaviour and increasing collision risk in certain traffic situations.

Considerations of a thick lens formula for intraocular lens power calculation

BackgroundIn recent years, some lens manufacturers have committed to providing lens shape data for some of their lens models. The purpose of this study is to present a strategy for prediction of intraocular lens power and residual refraction based on a pseudophakic model eye containing 5 refractive surfaces and to show its applicability using worked examples. MethodsA pseudophakic model eye with a thin spectacle correction, a thick cornea (radius of curvatures for both surfaces and central thickness) and a thick IOL (either radius of curvatures RLa and RLp for front and back surface or equivalent power PL and Coddington factor CL; and either central thickness LT or edge thickness and optic diameter) was set up. Calculations were performed based on linear Gaussian optics (vergence formulae). Formulae were provided to derive the lens power/shape and the residual equivalent spectacle refraction SEQ. From the lens shape the location of the haptic plane HP, the image sided principal plane of the lens HL, and the ocular magnification OM were extracted. ResultsThe calculation of a thick intraocular lens and the prediction of residual refraction is presented with reference to 3 working examples: A) lens varied in PL and shifted with its haptic plane keeping the CL constant, B) lens varied in CL and shifted with its haptic plane keeping PL constant, and C) CL and PL of the lens varied keeping its haptic plane position in the eye constant. For each combination of parameters (PL, CL, or haptic plane shift) the parameters influencing SEQ, OM and HL-HP were analysed. ConclusionSome modern optical biometers currently on the market provide the radii of curvature of both corneal surface and all relevant distances in the eye. With additional data on the lens shape, it would be possible to improve lens power calculations by switching from thin to thick lens models for the cornea and for the lens. This would overcome one of the major drawbacks of current lens power calculation methods.

Stabilization of refraction and timing of spectacle prescription following manual small-incision cataract surgery.

To determine the stabilization of refraction at 2 weeks following MSICS by comparing the difference in spherical, cylindrical component and also spherical equivalent of refraction of 2 weeks follow-up with that of 6 weeks following surgery. The difference of spherical, cylindrical component and also spherical equivalent of refraction at 2 weeks and 6 weeks follow-up of 194 eyes that underwent uncomplicated MSICS with implantation of PMMA IOL conducted by a single experienced surgeon were compared to find out the amount of change and its significance was statistically tested by Wilcoxon-Signed Rank Test. The difference in spherical power (0.04 ± 0.30), cylinder power (0.03 ± 0.40), and spherical equivalent (0.06 ± 0.34) were very small and not significant statistically (P-value ≤0.05). Necessary spectacle correction can safely be prescribed after 2 weeks following MSICS as subjective refraction stabilizes by that time without undergoing significant change. However, our observation was applicable in patients who had an uneventful cataract surgery without any risk factor, which can delay wound healing or cause poor visual outcome.

The Effect of Home-Based Dichoptic Therapy on Young Adults with Non-Strabismic Anisometropic Amblyopia on Stereo Acuity.

To evaluate the effect of home-based dichoptic visual therapy using anaglyphic red-green filters on the stereo acuity in a sample of young adults with non-strabismic anisometropic amblyopia. The study was observational and cross-sectional in design. Two groups (experimental vs control) were sourced using purposive sampling of young adults with non-strabismic amblyopia (experimental group) in comparison to an age-match control group without amblyopia. For the purpose of refractive adaptation, all participants in both groups were asked to wear their spectacle correction constantly for at least 16 weeks prior to exposure to home-based dichoptic therapy. Stereo acuity measurements using the Stereo Fly test were obtained before and after 40 hours exposure to home-based dichoptic therapy. The changes in stereo acuity post eight weeks (40 hours) training from baseline measurements was obtained. The difference in medians between the experimental and control groups using the Mann-Whitney U-test was measured with significance set at P value of <0.05. A total of 38 young adults (19 males, 19 females) with a mean age of 24.05 ± 5.66 years were enrolled in this study. Nineteen anisometropic amblyopes comprised the experimental group, fifteen of which were classified as moderate amblyopia (6/12-6/36) and 19 non-amblyopes comprised the control group. Home-based dichoptic therapy used on the experimental group after 8 weeks showed a significant improvement in stereo-acuity with a mean improvement of 345.26 ± 184.85 sec arc-1 [IQR:260;600; p<0.001] when compared to the control group. Home-based dichoptic therapy improved stereo-acuity in non-strabismic anisometropic amblyopes (moderate) in young adults. Thus suggesting that binocularity can improve in anisometropic adult amblyopes with a treatment modality that may be a convenient option better suit the demanding lifestyle of economically active adults who may not be able to comply with clinic-based therapy.

A randomized phase 2 clinical trial of phentolamine mesylate eye drops in patients with severe night vision disturbances

PurposeDim light vision disturbances (DLD) comprise a wide range of symptoms affecting the quality of vision at low illumination including glare, halos, and starbursts. This exploratory study investigated 1.0% phentolamine mesylate ophthalmic solution (PMOS) as a treatment to improve vision and image quality for patients with DLD.MethodsIn this placebo-controlled, randomized, double-masked clinical trial, 24 adult patients with severe DLD were randomized in a 2:1 ratio to receive either one dose of PMOS or placebo. Subjects were eligible if they reported experiencing severe night vision difficulty that was not eliminated by distance spectacle correction and scored ≥0.3 log units below the normal range of contrast sensitivity assessed under mesopic conditions with glare at ≥2 spatial frequencies. Key efficacy outcomes were change from baseline in pupil diameter, contrast sensitivity, and visual acuity. Safety measures including intraocular pressure, conjunctival hyperemia, and systemic effects were also assessed.ResultsEight subjects were randomized to placebo (63% female; mean age 47 years) and 16 were randomized to PMOS (75% female; mean age 42 years). Mean (SD) pupil diameter of PMOS-treated subjects decreased significantly − 1.3 mm (0 to − 2.8 mm) with p < 0.0001. Mean contrast sensitivity with glare in PMOS-treated subjects improved significantly post-treatment at spatial frequencies 3, 6, 12, and 18 cycles per degree (p ≤ 0.03). PMOS also demonstrated improvements in the numbers of letters read for mesopic and photopic, high- and low-contrast visual acuity (LCVA). Importantly, a statistically greater proportion of PMOS-treated eyes registered mesopic LCVA 5 letter (69% vs. 31%, p = 0.029) and 10 letter (34% vs. 6%, p = 0.04) improvement, with a trend at 15 letters (19% vs. 0%, p = 0.16). PMOS was well tolerated with the only reported side effect being a mild increase in conjunctival hyperemia.ConclusionPMOS was well tolerated and effectively reduced pupil size with improvements in contrast sensitivity and visual acuity in adults with severe DLD. Future Phase 3 studies should be conducted to further evaluate its potential to treat DLD.Trial registrationThe trial registration number is NCT04004507 (02/07/2019). Retrospectively registered.

Measurement of spectacle-induced aniseikonia in axial anisometropia using the New Aniseikonia Test

Aim To determine whether spectacle correction in axial anisometropes can cause significant aniseikonia. Patients and methods A cross-sectional study was conducted on eight patients who had axial anisometropia with a spherical equivalent difference between both eyes equal or more than 4 D. Aniseikonia was measured using the New Aniseikonia Test ‘Awaya.’ Aniseikonia of 3% or more was considered clinically significant. Spearman correlation between the amount of aniseikonia and anisometropia was calculated. Results The mean±SD age of the patients was 13±4.64 years (range, 7–24 years). Anisometropia ranging from −14.5 to +5.25 DS with a mean±SD of −6.70±5.18. The overall mean±SD of aniseikonia was −1.45±0.52. Five patients had no aniseikonia, three patients had −1% aniseikonia, and three patients had −2% aniseikonia. Spearman correlation showed an insignificant positive correlation between the amount of anisometropia and aniseikonia (r=0.05, P=0.86). Conclusion Among our cases, spectacle correction in axial anisometropia did not lead to significant aniseikonia using the New Aniseikonia Test. Aniseikonia should be assessed in patients with anisometropia as 1% of aniseikonia per diopter of anisometropia does not apply in every case.

Safety of DIMS Spectacle Lenses and Atropine as Combination Therapy for Myopia Progression.

The aim of this study was to evaluate traffic safety of Defocus Incorporated Multiple Segments (DIMS) spectacle lenses in combination therapy with atropine. 12 young adults (age: 24 - 45; 30,1 ± 5,7 years) were recruited to evaluate corrected distance visual acuity (CDVA), contrast sensitivity (CS; FrACT), glare sensitivity (Mesotest) under the influence of DIMS spectacle correction alone and combination therapy with 0,01% atropine. When looking through the central area of the DIMS lens, far vision does not decrease due to the influence of atropine; influence of glare and atropine leads to a reduction of CDVA by 0.10 logMAR. When forced to look through the DIMS area, far vision is reduced by 0.09 logMAR due to the influence of atropine in the absence of glare; in the presence of glare, no further loss of visual acuity can be observed under the influence of atropine. Contrast vision with DIMS glasses is not altered by the effects of atropine. Concerning glare sensitivity, DIMS lenses did not show any visual impairment that would be relevant to vision and road safety. Additional atropinization does not affect glare sensitivity. DIMS spectacle lenses are safe for participation in road traffic and do not relevantly impair traffic safety, neither alone nor under the acute influence of 0,01% atropine.