ABSTRACT
INTRODUCTION: Soft contact lenses may be a good alternative for early-stage keratoconus (KC) patients who do not tolerate rigid gas permeable (RGP) lenses due to ocular discomfort or complications. This prospective study compared outcomes obtained after 2 weeks of wearing two types of soft silicone hydrogel contact lenses for keratoconus that varied in their diameter and central thickness (cc). METHODS: Patients with Amsler-Krumeich grades I or II KC were fitted with small-diameter (14.2 or 14.8 mm) SoftK (SD-SoftK, cc = 0.48 mm) and large-diameter (17 mm) SoftK (LD-SoftK, cc = 0.60 mm) lenses, each worn for 2 weeks in a crossover design. Low (10%;10VA) and high (100%;100VA) contrast visual acuity, contrast sensitivity (CS, Pelli-Robson), higher order aberrations (HOAs, Visionix Vx130), the number of trial lens modifications during fitting and the subjectively preferred lens were compared using Friedman tests with post-hoc analysis. RESULTS: Forty eyes (N = 20, 10 males, mean age: 39.0 ± 9.9 years, range: 23-55 years) were examined. Their habitual median (interquartile1, interquartile3) 10VA (LogMAR), 100VA (LogMAR) and CS (LogCS) were 0.52 (0.30, 0.50), 0.14 (0.10, 0.15) and 1.35 (1.35, 1.50), respectively. For the SD-SoftK condition, the values were 0.23 (0.17, 0.30), 0.02 (0.00, 0.05) and 1.50 (1.50, 1.65), respectively. For the LD-SoftK condition, the respective values were 0.36 (0.27, 0.44), 0.09 (0.05, 0.13) and 1.50 (1.50, 1.60). SD-SoftK lenses significantly improved 10VA compared with habitual and LD-SoftK. SD-SoftK also significantly improved CS compared with habitual, but not LD-SoftK. LD-SoftK significantly improved spherical aberration compared with uncorrected (0.03 ± 0.10 µ vs. 0.07 ± 0.13 µ) but not SD-SoftK (0.04 ± 0.07 µ). Both lenses required a mean of 1.5 modifications prior to final lens fitting. Fewer adverse events were seen with SD-SoftK (N = 3) compared with LD-SoftK (N = 8), and 75% of participants preferred SD-SoftK lenses. CONCLUSION: SD-SoftK lenses were preferred by 75% of subjects, were associated with fewer adverse events and significantly improved 10VA compared with LD-SoftK lenses. SD-SoftK lenses also significantly improved CS compared with the habitual correction, but this did not differ significantly from the LD-SoftK lenses.
Subject(s)
Contact Lenses, Hydrophilic , Contrast Sensitivity , Corneal Topography , Cross-Over Studies , Keratoconus , Visual Acuity , Humans , Keratoconus/diagnosis , Keratoconus/physiopathology , Keratoconus/therapy , Male , Female , Prospective Studies , Adult , Visual Acuity/physiology , Young Adult , Contrast Sensitivity/physiology , Corneal Topography/methods , Middle Aged , Equipment Design , Refraction, Ocular/physiologyABSTRACT
INTRODUCTION: This study investigated the equivocal association between contact lens (CL) wear and meibomian gland dysfunction (MGD) by comparing the morphological, functional and subjective outcomes of CL wearers versus control, non-CL wearers. CL wearers were examined as two cohorts based on the annual attendance of follow-up visits (FLU-attended these visits, whereas non-FLU did not). METHODS: Habitual logMAR visual acuity, invasive and non-invasive tear break-up time, Schirmer test, Efron grading scales, meibum quality score (MQS), meibum expressibility score (MES), meibomian gland (MG) loss, lid margin abnormalities and subjective dry eye (DE) symptoms were assessed. RESULTS: Of the 128 participants, 31 were in the FLU cohort, 43 were in the non-FLU cohort and 54 were controls (mean ages: 22.2 ± 3.1, 23.0 ± 4.6 and 22.3 ± 3.5, respectively). Non-FLU CL wearers had more symptoms than controls (3.7 ± 2.4 vs. 2.3 ± 2.1, p < 0.01). Morphologically, FLU (16.9 ± 8.8%, p = 0.02) and non-FLU (18.6 ± 11.3%, p = 0.001) had more MG loss than controls (11.2 ± 6.8%). Functionally, FLU (0.6 ± 0.7, p = 0.01) and non-FLU (0.8 ± 0.9, p = 0.001) had worse MES than controls (0.2 ± 0.5). FLU and non-FLU were both associated with corneal staining (odds ratio [OR] = 3.42, 95% CI: 1.16-10.11, p = 0.03 and OR = 5.23, 95% CI: 1.89-14.48, p = 0.001, respectively) and MG loss (OR = 10.47, 95% CI: 1.14-96.29, p = 0.04 and OR = 16.63, 95% CI: 1.96-140.86, p = 0.01, respectively). Non-FLU CL wear was also associated with abnormal MQS (OR = 12.87, 95% CI: 1.12-148.41, p = 0.04), conjunctival staining (OR = 12.18, 95% CI: 3.66-40.51, p < 0.001) and lid margin telangiectasia (OR = 3.78, 95% CI: 1.55-9.21, p = 0.003). MGD was three times more prevalent in CL wearers (12%) than in controls (4%). CONCLUSIONS: Both CL-wearing cohorts demonstrated significantly more MG abnormalities than controls though the difference was not clinically significant. Non-FLU CL wearers had more DE symptoms. Non-FLU CL wear is an independent predictor for more abnormalities than FLU CL wear, emphasising the importance of follow-ups.
Subject(s)
Contact Lenses , Dry Eye Syndromes , Meibomian Gland Dysfunction , Humans , Follow-Up Studies , Meibomian Glands , Conjunctiva , Tears , Dry Eye Syndromes/diagnosisABSTRACT
PURPOSE: The inter-session repeatability (ISR), inter-examiner reproducibility (IER) and within-subject variability (WSV) of the Cobra HD fundus camera meibographer were examined in participants with and without dry eye symptoms. METHODS: Symptoms were determined based on Ocular Surface Disease Index scores (≥13 being considered symptomatic), and subgroups were compared using the Mann-Whitney U-test. Images of meibomian glands (MGs) from the upper and lower right eyelids were captured by two examiners on the same day (S1) to determine IER. One examiner repeated the measurements on a second day (S2) to obtain the ISR. ISR, IER and WSV were calculated using Friedman, correlation tests and Bland and Altman analyses with mean differences (md) and 95% confidence intervals (CIs), within-subject standard deviations (Sw) and intra-class correlation coefficients (ICC). RESULTS: The ISR experiment included 72 participants (mean age: 23 ± 5 years, range: 19-43, 36 symptomatic). Mean MG loss of the upper (S1: 13.5 ± 9.5%, S2: 12.8 ± 8.5%) and lower eyelids (S1: 7.5 ± 6.9%, S2: 7.3 ± 6.3%) was not significantly different between sessions for all participants, symptomatic and asymptomatic subgroups for both eyelids. The ISR Sw for the upper and lower eyelids was 1.3% and 1.0%; md was 0.7 ± 3.5% (CI:-6.25% to 7.62%) and 0.1 ± 2.1% (CI: -3.94% to 4.17%), respectively. The IER experiment included 74 participants (mean age: 23 ± 5 years, range: 19-43, 37 symptomatic). Mean MG loss of the upper (Examiner 1: 12.7 ± 8.2%, Examiner 2: 13.1 ± 8.0%) and lower eyelids (Examiner 1: 7.0 ± 6.2%, Examiner 2: 7.4 ± 6.2%) was not significantly different between examiners for all participants, symptomatic and asymptomatic subgroups for both eyelids. The IER ICC values were >0.86 for all conditions, Sw was 1.3% and 1.2%, with a md of -0.4 ± 3.2% (CI: -6.65% to 5.90%) and -0.4 ± 2.9% (CI: -6.15% to 5.31%), respectively. The WSV Sw values were <1.4%, and ICC values were >0.89 for both eyelids, examiners and experimental sessions. CONCLUSIONS: The Cobra HD fundus camera demonstrates good repeatability, reproducibility and low WSV, and is a reliable clinical instrument for meibography.
Subject(s)
Dry Eye Syndromes , Eyelid Diseases , Humans , Young Adult , Adolescent , Adult , Reproducibility of Results , Eyelid Diseases/diagnosis , Meibomian Glands/diagnostic imaging , Dry Eye Syndromes/diagnosis , TearsABSTRACT
PURPOSE: Assess the refractive states of donkeys and goats. METHODS: Forty-two donkeys and 28 goats were enrolled. The mean ± SD ages were 7.68 ± 7.33 years for donkeys and 4.26 ± 2.33 years for goats. Seven donkeys and one goat were <6 months old. Retinoscopy was performed in alert animals, following cycloplegia in goats but not in donkeys. Normality was determined using the Kolmogorov-Smirnov test. The two primary meridians and two eyes were compared using Pearson's correlation and paired Student's t-tests. The association between refractive states and age was examined using one-way ANOVA in donkeys and a paired Student's t-test in goats. One-sample t-tests were conducted to assess if the refractive error distributions were significantly different from "0". RESULTS: The mean ± SD spherical equivalent (SE) refractive errors of the right and left donkey eyes were -0.80 ± 1.03 D and -0.35 ± 0.95 D, respectively. The majority (86%) of the donkeys had an astigmatic refraction and eight (19%) had anisometropia. The mean SE refractive errors of the right and left goat eyes were -0.15 ± 1.1 D and -0.18 ± 1.2 D, respectively. The majority (54%) of the goat eyes had an astigmatic refraction and five (18%) had anisometropia. The right and left eye SE refractive errors were positively correlated in both species (both p = .9). Age was not correlated with refractive error in both donkeys (p = .09) and goats (p = .6). CONCLUSIONS: Both goats and donkeys are emmetropic.
Subject(s)
Anisometropia , Goat Diseases , Refractive Errors , Animals , Retinoscopy , Anisometropia/veterinary , Equidae , Goats , Refractive Errors/veterinary , Refraction, Ocular , PrevalenceABSTRACT
PURPOSE: Motor vehicle accidents (MVAs) are a pandemic associated with human suffering and a burden to national economies. Whiplash-associated disorders (WADs) after MVAs are associated commonly with disability claims, many of which are related to vision. Convergence insufficiency (CI) leads to visual disability associated with symptoms of ocular discomfort. We examined the incidence of symptoms and findings consistent with CI in a cohort of patients after MVA-related WAD compared with age-matched control participants. DESIGN: Prospective cohort study. PARTICIPANTS: Patients with WAD after MVA were recruited from the Orthopedic Emergency Department between July 2014 and March 2017. Control participants were recruited among hospital personnel and relatives of WAD patients. METHODS: The Convergence Insufficiency Symptom Survey (CISS) questionnaire was completed by each participant, followed by a detailed visual examination including measurements of distance and near best-corrected Snellen visual acuity, distance and near cover test, Randot stereopsis, Maddox distance and Maddox-Thorington near heterophoria, near point of convergence, base-out step fusional reserves, and amplitude of accommodation using the push-away method. MAIN OUTCOME MEASURES: The CISS score and binocular measure findings of CI were recorded and analyzed using Student's t test, the chi-square test, and multiple logistic regression adjusted for age and gender. RESULTS: A pathologic CISS score of 16 or more occurred in 26 of 57 WAD patients (45.6%) compared with 6 of 39 control participants (15.4%; P = 0.002). Absolute CISS score was higher in the WAD group compared with the control group (15.3±10.0 vs. 7.7±7.7; P < 0.001). Findings consistent with CI occurred in 7.0% of WAD patients and 7.7% of control participants (P = 0.90). CONCLUSIONS: Visual symptoms suggestive of CI were reported more frequently among WAD patients compared with control participants, yet the incidence of examination findings indicating weakness of convergence was not increased. The discrepancy between subjective and objective measures of CI in WAD patients versus control participants stresses the importance of training healthcare personnel to assess disability using objective, validated standards of examination.
Subject(s)
Accidents, Traffic , Ocular Motility Disorders/diagnosis , Vision Disorders/diagnosis , Whiplash Injuries/diagnosis , Accommodation, Ocular/physiology , Adult , Cohort Studies , Depth Perception/physiology , Female , Humans , Male , Middle Aged , Ocular Motility Disorders/physiopathology , Prospective Studies , Surveys and Questionnaires , Vision Disorders/physiopathology , Vision, Binocular/physiology , Visual Acuity/physiology , Whiplash Injuries/physiopathology , Young AdultABSTRACT
PURPOSE: To determine the prevalence of choroidal naevi in a healthy population using an ultra-wide scanning laser ophthalmoscope which can capture up to a 200° field of view of the retina, without pupil dilation. METHODS: Subjects were recruited from a college population. Each subject underwent an eye examination that included retinal and choroidal imaging using the Optos scanning laser ophthalmoscope and completed a self-administered questionnaire. Univariate and multivariate regression analysis were performed to identify associated factors with choroidal naevi. RESULTS: The Optomap images of 406 participants (mean age 23.5 ± 4.4) were analysed. Thirty-nine subjects (10%) presented with at least one naevus in one eye, and multiple naevi were observed unilaterally in eight subjects. Drusen were noted in only one eye. The mean naevus diameter was 2.38 mm (± 2.07). Prevalence was not associated with either eye colour, time spent outdoors, visual impairment, or ethnic group, but was significantly associated with male gender (OR 2.41, p = 0.009), blond/red hair colour (OR 2.42, p = 0.037), skin that neither burns nor tans (OR 2.8, p = 0.02) and habitual sunglasses use (OR 0.33, p = 0.002). CONCLUSIONS: A higher prevalence of choroidal naevi was detected in this college population compared to other population-based studies. This is likely due to the use of an ultra-wide field scanning laser ophthalmoscope which provides up to 200° of the fundus. The naevi were associated with several factors.
Subject(s)
Choroid Neoplasms/epidemiology , Nevus/epidemiology , Ophthalmoscopes , Ophthalmoscopy/methods , Adolescent , Adult , Choroid Neoplasms/diagnosis , Female , Humans , Israel/epidemiology , Lasers , Male , Nevus/diagnosis , Regression Analysis , Young AdultABSTRACT
OBJECTIVE: To evaluate refractive state outcomes following phacoemulsification and implantation of 3 different intraocular lenses (IOLs). ANIMALS: A prospective, randomized, controlled study was conducted on 43 client-owned dogs undergoing phacoemulsification with IOL implantation. METHODS: Eyes were randomized to receive either an-vision Fo-X (n = 26), an-vision MD8 (18), or I-MED I-LENS (24) IOL. Refraction was measured 1 week, 1 month, and 3 months postoperatively using streak retinoscopy by 2 examiners masked to each other's results. RESULTS: Postoperative refractive outcomes were highly correlated and not significantly different between 2 examiners for all time points (r = 0.97, 0.98, and 1.00; P = .76, .94, and .98, respectively). One week postoperatively, the refractive errors (mean ± SD) for Fo-X, MD8, and I-LENS were -0.14 ± 2.02 diopters (D), 0.97 ± 2.01 D, and 0.15 ± 2.55 D, respectively. One month postoperatively, the refractive errors were 0.35 ± 2.04 D, 0.06 ± 2.41 D, and -0.82 ± 2.20 D, respectively. Three months postoperatively, the refractive errors were -0.16 ± 2.67 D, 1.60 ± 2.99 D, and 0.59 ± 1.51 D, respectively. There were no significant differences in refractive error outcomes between Fo-X, MD8, and I-LENS at 1 week, 1 month, and 3 months postoperatively (P = .16; F(df=2,66)- = 1.89). However, the Fo-X was the only IOL to yield nearly emmetropic outcomes (±0.50 D) at all 3 time points. CLINICAL RELEVANCE: The postoperative refractive states of dogs were not statistically different when comparing 3 types of IOLs at 3 postoperative time points, though the Fo-X was the only IOL to yield nearly emmetropic outcomes at all 3 time points.
Subject(s)
Cataract , Dog Diseases , Lenses, Intraocular , Phacoemulsification , Refractive Errors , Animals , Dogs , Cataract/veterinary , Dog Diseases/surgery , Lens Implantation, Intraocular/veterinary , Lens Implantation, Intraocular/methods , Lenses, Intraocular/veterinary , Phacoemulsification/veterinary , Prospective Studies , Refractive Errors/veterinary , Retrospective StudiesABSTRACT
Purpose: Astigmatism blurs the retinal image of a circular spot along a particular orientation rendering it an elliptical shape. Astigmatic patients demonstrate adaptation to residual astigmatic blur that may affect their discrimination between oval and circular targets. The Wilkins Egg and Ball Test (WEBT) was created to detect altered visual perception due to residual astigmatic blur by discriminating a circle within a row of oval elements. This prospective, cross-sectional study examined the utility of WEBT in detecting uncorrected residual astigmatism on the perception of form symmetry in astigmatic and keratoconic participants as well as normal participants with induced astigmatism at four primary meridians. Methods: The mean search time (sT) and number of errors (noE) of 33 non-astigmatic controls (mean age: 24±5, range: 18-43, 6 males), 23 astigmatic participants (mean age: 36±12, range: 18-43, 6 males) and 13 keratoconic participants (N=22 eyes, mean age: 36±12, range: 18-58, 6 males) were measured under baseline, and 2.00 DC induced cylinder at four primary meridians, and for uncorrected, spherical-correction only, and fully corrected conditions, respectively. Mean sT and noE were converted to Z-scores, combined for each condition, and compared using repeated measures ANOVA with post-hoc analysis. Results: Combined Z-scores for the controls were significantly worse (p<0.001) for all induced cylinder conditions. The induced 180° condition was significantly better than 45° and 90° conditions (p=0.04), but not the 135° condition. For both astigmatic and keratoconic cohorts, Z-scores of the uncorrected condition were significantly worse than the fully corrected condition (both p<0.01), but the fully corrected and spherical-only conditions did not differ significantly (p=0.06 and p=0.05, respectively). Conclusion: In accommodating young adults, WEBT detected altered visual perception due to overall blur, and moderate-high amounts of uncorrected induced astigmatism and keratoconus, but is not useful as a tool for detection of altered visual perception due to small residual astigmatic blur.
ABSTRACT
Contact lens (CL) wearers often suffer from ocular discomfort, which leads to cessation of CL wear. About 30% to 50% of CL wearers complain of dry eye (DE) symptoms. Meibomian gland dysfunction (MGD) is considered the most common cause of evaporative DE. Numerous studies have investigated whether CL wear might affect the meibomian glands. This manuscript reviews studies examining the relationship between CL use and MGD. A PubMed database search was conducted for studies published between 1980-2021 with one or a combination of search terms related to "meibomian gland", "meibomian gland dysfunction", "contact lens", and/or "dry eye". Of the 115 papers reviewed, 22 articles were identified that examined the association between CL and MGD. Fifteen showed that CL wear affects the morphology and function of meibomian glands (MGs), while seven reported no significant impact of CL wear on MGs. This review provides an overview of these studies, emphasizing the diagnostic tests of MGD and conclusions. The review highlights the need for longitudinal prospective large cohort studies with control non- CL wearers to clarify the ambiguous relationship between MGD and CL wear, with special attention to varying CL material and wear times in order to identify the long-term impact of CLs on MG.
Subject(s)
Contact Lenses , Dry Eye Syndromes , Meibomian Gland Dysfunction , Humans , Prospective Studies , Tears , Meibomian Gland Dysfunction/complications , Contact Lenses/adverse effects , Meibomian Glands , Dry Eye Syndromes/etiologyABSTRACT
PURPOSE: The dynamic optotype (DYOP) visual acuity (VA) test is based on motion detection rather than element resolution and has been proposed for routine clinical assessment. This investigation examined the validity, inter- and intra-session repeatability and subjective preference for the DYOP versus a static letter chart and examined its utility in detecting astigmatic defocus. METHODS: VA of 103 participants was measured three times with the letter and DYOP charts and repeated within two weeks in 75 participants who also rated their subjective experience. The VA of 29 participants was measured using DYOP, letter, Landolt C, and Tumbling E charts, with habitual correction and astigmatism induced with +1.00, +2.00 or +3.00 cylinders at 45, 60, 90 and 180°. RESULTS: The charts differed by a mean of 0.02 logMAR, with 81% of the measurements within one line of acuity. Inter-session, intraclass correlation coefficients, within-subject SD and repeatability were 0.03 logMAR, 0.95, 0.11 and 0.30 versus 0.01 logMAR, 0.92, 0.15 and 0.42 for the DYOP and letter charts, respectively. The DYOP was significantly more frustrating (1.79 vs.1.36), with 59% preferring the letter chart. The DYOP was least affected by induced astigmatism. CONCLUSIONS: The DYOP and letter charts differed significantly in their mean values with wide limits of agreement. DYOP had better within-subject SD and narrower limits of agreement between sessions, though clinically insignificant, and performed significantly worse for the detection of uncorrected astigmatism. Thus, it is difficult to recommend this test for the clinical determination of refractive error.
ABSTRACT
PURPOSE: Previous studies considered the possibility that individuals with impaired stereoacuity can be identified by estimating the perceived depth of a target with a suprathreshold retinal image disparity. These studies showed that perceived suprathreshold depth is reduced when the image presented to one eye is blurred, but they did not address whether a similar reduction of perceived depth occurs when the stereothreshold is elevated using other manipulations. METHODS: Stereothresholds were measured in six adult observers for a pair of bright 1-degree vertical lines during normal viewing and under five conditions that elevated the stereothreshold: monocular dioptric blur, monocular glare, binocular luminance reduction, monocular luminance reduction, and imposed disjunctive image motion. The observers subsequently matched the perceived depth of degraded targets presented with crossed or uncrossed disparities corresponding to two, four, and six times the elevated stereothreshold for each stimulus condition. RESULTS: The image manipulations used elevated the stereothreshold by a factor of 3.7 to 5.5 times. For targets with suprathreshold disparities, monocular blur, monocular luminance reduction, and disjunctive image motion resulted in a significant decrease in perceived depth. However, the magnitude of perceived suprathreshold depth was unaffected when monocular glare was introduced or the binocular luminance of the stereotargets was reduced. CONCLUSIONS: Not all conditions that increase the stereothreshold reduce the perceived depth of targets with suprathreshold disparities. Observers who have poor stereopsis therefore may or may not exhibit an associated reduction of perceived suprathreshold depth.
Subject(s)
Depth Perception/physiology , Vision Disparity/physiology , Vision, Binocular/physiology , Visual Acuity , Adult , Female , Humans , Male , Middle Aged , Sensory Thresholds , Young AdultABSTRACT
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.
Subject(s)
Accommodation, Ocular , Ocular Motility Disorders , Convergence, Ocular , Humans , Ocular Motility Disorders/diagnosis , Ocular Motility Disorders/epidemiology , Vision Disorders/diagnosis , Vision, BinocularABSTRACT
PURPOSE: Reports of dissimilar stereothresholds for contour and random-dot (RD) targets may reflect differences in stimulus properties or differences between local and global stereoscopic processing mechanisms. In this study, we evaluated whether the stereothresholds obtained using low- and high-density RD stimuli are consistent with a distinction between local and global disparity processing. METHODS: Stereothresholds were measured in eight normal subjects for a small disparate line segment superimposed on RD surrounds with densities that ranged between 0.07 and 28.3%. RESULTS: Stereothresholds averaged 0.23 arc min for an RD density of 0.39% and approximately doubled for lower and higher densities. The increase in stereothresholds at low densities is likely because of the increased spacing between elements, which reduces their usefulness as a reference for relative disparity judgments. The increase in stereothresholds at high densities is attributed to a crowding effect. CONCLUSIONS: Because the stereothresholds measured with RD stimuli of low and high density are limited by different constraints, they can be considered to be different types of stereotargets. However, because the stereothresholds measured for RD targets of varying densities are similar to those determined previously for a local, two-rod stereotarget, it is likely that all these stimuli are processed by a single disparity-processing mechanism.
Subject(s)
Depth Perception/physiology , Photic Stimulation/methods , Reaction Time/physiology , Sensory Thresholds/physiology , Vision, Binocular/physiology , Adult , Computer Graphics , Female , Follow-Up Studies , Humans , Male , Middle Aged , Reference Values , Young AdultABSTRACT
BACKGROUND: Interpupillary distance (IPD) is important in developmental anatomy, genetics, design of optical instrumentation, ocular diagnostics, and optical prescribing. IPD frequently is measured on different days, and by either automatic pupillometers (physiological measurement) or manual ruler (anatomical measurement). Therefore, there is importance in the agreement and inter-session repeatability of manual and automatic IPD measurements. METHODS: Monocular distance from the bridge of the nose and binocular distance and near binocular IPD were randomly measured, using a millimeter ruler and the Essilor Pupillon pupillometer. Gender effects were assessed using Wilcoxon and Mann-Whitney tests, respectively. Agreement was assessed using Spearman correlation and Bland-Altman (B&A) plots. Thirty additional participants were tested within 1-2 weeks to determine the inter-session repeatability. RESULTS: The agreement study included 199 participants (mean age: 24.1 ± 5.0 range: 19-53, 58 male, 141 female) and the repeatability sub- study included 30 (mean age: 27.9 ± 4.5, range: 23-39, 6 male, 24 female). Males and females significantly differed in age (<2 year mean difference (md)) and IPD (monocular md: < 1 mm, binocular md: < 2 mm). Manual vs. automatic measurements were significantly different for all conditions (md: <1 mm for all) except for distance left eye male PD. There was no significant difference between the session for both methods. CONCLUSIONS: Binocular and monocular manual and automatic measurements were significantly different statistically, but not clinically. Distance binocular IPD was approximately 3 mm wider than near IPD. Male binocular IPD was approximately 2 mm wider than the female IPD. Both methods had good inter-session repeatability.
Subject(s)
Diagnostic Techniques, Ophthalmological , Pupil , Adult , Female , Humans , Male , Young AdultABSTRACT
Purpose: Heterophoria describes the deviation of the optical axes in the absence of binocular fusion. Eye trackers (ET) can provide an objective assessment but are not broadly used clinically. We examined the feasibility of combining an infrared (IR) pass-filter, IR detector, and an off-the-shelf ET. The proposed setup was validated against the broadly used cover test (CT). Furthermore, the setup was used to examine whether testing conditions can affect the measurements. Methods: An IR detector was attached to a handheld IR-pass filter that blocks visible light to provide occlusion while passing IR light for eye tracking. The detector senses the IR illumination of the eye tracker, creating a recordable signal of the occluder position synchronized with eye positions acquired by the SMI Red250 tracker. The mean of three measurements of each condition, three versus ten seconds occlusion, the occluded eye, and ET versus CT results were compared using the Wilcoxon test, correlation and Bland and Altman plots. Differences between measurements that were within 2Δ were considered clinically insignificant. Results: Thirty normally-sighted subjects (mean age 24.50 ± 2.20, range 20-28) with heterophoria ranging between 14Δ exophoria and 4Δ esophoria were recruited. There was no significant difference between the occluded eyes. However, there was a difference between 3 and 10 seconds' cover duration. The CT data were more similar to the 10 seconds cover duration, although differences were less than the clinical resolution of 2Δ. Conclusions: An inexpensive off-the-shelf ET can be used to measure heterophoria with controlled testing parameters. Translational Relevance: Our study demonstrated a robust technique for synchronization of an optical element such as an IR cover, with an off-the-shelf commercial eye tracker. The synchronization of optical elements with eye tracking, which has been described here for heterophoria, can be adapted for other clinical measurements.
Subject(s)
Esotropia , Exotropia , Optical Devices , Strabismus , Adaptation, Physiological , Adult , Humans , Young AdultABSTRACT
AIM: To detect alphabet patterns in a group of patients without strabismus and to determine whether they induced any convergence insufficiency type symptoms. METHODS: Data on subjective refraction, distance and near heterophoria, distance and near positive fusional vergence (BO), near point of convergence (NPC), measurements of upgaze and downgaze made 45° above and below the primary position with alternate cover test and a prism bar at a distance of 37.5 cm, were collected from participants of two clinics. Symptoms were assessed using the 15-item Convergence Insufficiency Symptoms Survey (CISS) to determine a symptom score. Association between alphabet patterns and the other variables was analyzed using parametric and non-parametric tests. RESULTS: Out of 122 patients, 14 were found to present an alphabet pattern. Defining a V pattern exophoria ≥15-prism dioptre or ≥10-prism dioptre deviation, three patients (2.5%) and 12 patients (9.8%) were identified, respectively. In addition, one case resembled an X pattern and another a diamond pattern. The refraction, distance and near heterophoria, positive fusional vergence and CISS scores were not significantly different in the participants with V pattern compared to those without V pattern. CONCLUSION: Alphabet patterns, especially V type, were demonstrated in approximately 11.5% of a sample of 122 non-strabismus patients. These alphabet patterns were found not to be associated with convergence insufficiency-like symptoms.
ABSTRACT
Achromatopsia is an inherited retinal disease characterized by loss of cone photoreceptor function. Day blind CNGA3 mutant Improved Awassi sheep provide a large animal model for achromatopsia. This study measured refractive error and axial length parameters of the eye in this model and evaluated chromatic pupillary light reflex (cPLR) testing as a potential screening test for loss of cone function. Twenty-one CNGA3 mutant, Improved Awassi, 12 control Afec-Assaf and 12 control breed-matched wild-type (WT) Awassi sheep were examined using streak retinoscopy and B-mode ocular ultrasonography. Four CNGA3 mutant and four Afec-Assaf control sheep underwent cPLR testing. Statistical tests showed that day-blind sheep are significantly more myopic than both Afec-Assaf and WT Awassi controls. Day-blind sheep had significantly longer vitreous axial length compared to WT Awassi (1.43 ± 0.13 and 1.23 ± 0.06 cm, respectively, p < 0.0002) and no response to bright red light compared to both controls. Lack of response to bright red light is consistent with cone dysfunction, demonstrating that cPLR can be used to diagnose day blindness in sheep. Day-blind sheep were found to exhibit myopia and increased vitreous chamber depth, providing a naturally occurring large animal model of myopia.
Subject(s)
Color Vision Defects/diagnosis , Color Vision Defects/physiopathology , Cyclic Nucleotide-Gated Cation Channels/genetics , Myopia/diagnosis , Myopia/physiopathology , Retinal Cone Photoreceptor Cells/physiology , Vision Disorders/diagnosis , Vision Disorders/physiopathology , Animals , Disease Models, Animal , Electroretinography , Female , Light , Male , Mutation , Photoreceptor Cells, Vertebrate/metabolism , Pupil , Refractive Errors , Retina/metabolism , Retinoscopy , Sheep , Sheep, Domestic , Ultrasonography , Vision, OcularABSTRACT
Two case studies in the literature report on patients with infantile nystagmus (IN) who preferred to read text that is oriented vertically rather than horizontally. The current study systematically evaluated the effect of text orientation (-60 to +90â¯deg with respect to horizontal) on reading speed in nine individuals with IN associated with albinism at Hadassah Academic College (HAC), seven individuals with IN at the University of Houston (UH), and a total of 17 normal control observers. Observers at HAC read 40-character passages of Hebrew text from standardized 2nd grade level reading material and observers at UH read MNRead acuity chart sentences. Letter size was two to six lines larger than each observer's measured visual acuity. In both individuals with IN and normal observers reading speed was fastest for horizontally oriented text and decreased for other orientations. However, reading speed decreased significantly more for non-horizontally orientated text in the observers with IN, compared to controls. In general, it is recommended that to achieve best reading performance patients with IN read horizontally oriented text.