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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 astigmat, This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors. Parts of this study were funded by the Hadassah Academic College Conference and Research Board grant awarded to Eyal Gal., Peer Reviewed, Postprint (published version)

Liat Gantz,1 Joan Gispets,2 Arnold Wilkins,3 Eyal Gal1,2 1Department of Optometry and Vision Science, Hadassah Academic College, Jerusalem, Israel; 2University Vision Centre, Universitat Politècnica de Catalunya, Terrassa, Barcelona, Spain; 3Department of Psychology, University of Essex, Colchester, UKCorrespondence: Liat Gantz, Email liatg@hac.ac.il

Eyal Gal,1,2 Joan Gispets,2 Arnold Wilkins,3 Meira Zyroff,1 Efrat Netanya‌,1 Liat Gantz1 1Department of Optometry and Vision Science, Hadassah Academic College, Jerusalem, Israel; 2University Vision Centre, Universitat Politècnica de Catalunya, Terrassa, Barcelona, Spain; 3Department of Psychology, University of Essex, Colchester, UKCorrespondence: Liat Gantz; Eyal Gal, Department of Optometry and Vision Science, Hadassah Academic College, 37 Hanevi’im St, Jerusalem, Jerusalem, 9101001, Israel, Email liatg@hac.ac.il; gale@hac.ac.ilPurpose: 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 condition

(English) Meibomian gland dysfunction (MGD) is a chronic and diffuse abnormality of the meibomian glands (MGs) that occurs in 38% of contact lens (CL) wearers, though the influence of CLs on MGD is equivocal. A topical literature review examining the influence of CL wear on MGs found 15 studies reporting an effect of CLs on MGs vs. seven studies who did not. Discrepancies may be due to varying definitions of MGD, types of questionnaires, assessment methods, CL types, and measurement of one vs. both eyelids. The review concluded that the effect of CL wear on MGD should be addressed with a prospective study including non-CL wearing controls and employing an objective assessment of MGs. The Cobra HD meibographer is an objective instrument used in research studies whose inter-session repeatability (ISR), inter-examiner reproducibility (IER) and within-subject variability (WSV) has not been investigated. These measures were evaluated in participants with and without dry eye (DE) symptoms based on their Ocular Surface Disease Index (OSDI) questionnaire. Seventy-two participants (mean age: 23±5 years, 36 asymptomatic) were examined by Examiner 1 in sessions S1 and S2 to calculate the ISR, and seventy-four (mean age: 23±5 years, 37 asymptomatic) were measured on the same day by examiners E1 and E2 to determine the IER. WSV was determined from three consecutive measurements of the same eyelid. Mean MG loss of the upper (S1:13.5±9.5%,S2:12.8±8.5%, E1:12.7±8.2%, E2:13.1±8%) and lower eyelids (S1:7.5±6.9%,S2:7.3±6.3%, E1:7±6.2%, E2:7.4±6.2%) was not significantly different between sessions or examiners for all cohorts for both eyelids. The ISR within-subject standard deviations (Sw) for the upper and lower eyelids were 1.3% and 1.0%; mean difference (md) was 0.7±3.5% [CI:-6.25%- 7.62%] and 0.1±2.1% [CI:-3.94%- 4.17%], respectively. IER ICC values were >0.86 for all conditions, Sw was 1.3% and 1.2% with md of -0.4±3.2% [CI:-6.65%- 5.9%] and -0.4±2.9% [CI:-6.15%- 5.31%], respecti, (Català) La disfunció de les glàndules de Meibomi (MGD) és una anomalia crònica i difusa de les glàndules de Meibomi (MG) que ocorre en el 38% dels usuaris de lents de contacte (LC), encara que la seva influència a la MGD és equívoca. Una revisió de la literatura especialitzada va trobar 15 estudis que van informar d’un efecte de les LC a les MG enfront de set que no. Les discrepàncies poden ser degudes a les diferents definicions de MGD, tipus de qüestionaris, mètodes d'avaluació, tipus de LC i mesurament d'una o de les dues parpelles. Es va concloure que la influència de les LC a la MGD hauria d'abordar-se amb estudis prospectius que incloguin controls no usuaris i una avaluació objectiva. El meibògraf Cobra HD és un instrument de recerca del qual no s’han constatat la repetibilitat entre sessions (ISR), reproductibilitat inter examinadors (IER) i variabilitat intra subjecte (WSV). Aquestes mesures es van avaluar en participants amb símptomes d'ull sec i sense (DE) segons el qüestionari de l'Índex de malaltia de la superfície ocular (OSDI). 72 participants (23±5 anys, 36 asimptomàtics) van ser avaluats per l'examinador 1 a les sessions S1 i S2 per calcular la ISR, i 74 (23±5 anys, 37 asimptomàtics) el mateix dia pels examinadors E1 i E2 per a determinar la IER. La WSV es va establir a partir de tres mesures consecutives de la mateixa parpella. La pèrdua mitjana de MG de les parpelles superior (S1:13.5±9.5%, S2:12.8±8.5%, E1:12.7±8.2%, E2:13.1±8%) i inferior (S1:7.5±6.9 %, S2:7.3± 6.3%, E1:7±6.2%, E2:7.4±6.2%) no va ser significativament diferent entre sessions ni examinadors per a totes les cohorts i per a les dues parpelles. Les desviacions estàndard (Sw) de la ISR intra subjecte per a les parpelles superior i inferior van ser 1.3 % i 1 %; la diferència mitjana (md) va ser 0.7±3.5% i 0.1±2.1%, respectivament. Els valors de IER ICC van ser >0.86 per a totes les condicions, la Sw 1.3% i 1.2% amb md -0.4±3.2% i -0.4±2.9%, respectivament. La Sw WSV <1.4 % i els valor, (Español) La disfunción de las glándulas de Meibomio (MGD) es una anomalía crónica y difusa de las glándulas de Meibomio (MG) que ocurre en el 38 % de los usuarios de lentes de contacto (LC), aunque su influencia en la MGD es equívoca. Una revisión de la literatura especializada encontró 15 estudios que informaron un efecto de las LC en las MG frente a siete que no. Las discrepancias pueden deberse a las distintas definiciones de MGD, tipos de cuestionarios, métodos de evaluación, tipos de LC y medición de uno frente a ambos párpados. Se concluyó que la influencia de las LC en la MGD debería abordarse con estudios prospectivos que incluya controles no usuarios y la evaluación objetiva. El meibógrafo Cobra HD es un instrumento de investigación cuya repetibilidad entre sesiones (ISR), reproducibilidad inter examinadores (IER) y variabilidad intra sujeto (WSV) no han sido determinadas. Estas medidas se evaluaron en participantes con y sin síntomas de ojo seco (DE) según el cuestionario del Índice de enfermedad de la superficie ocular (OSDI). 72 participantes (23±5 años, 36 asintomáticos) fueron evaluados por el examinador 1 en las sesiones S1 y S2 para calcular la ISR, y 74 (23±5 años, 37 asintomáticos) en el mismo día por los examinadores E1 y E2 para determinar la IER. La WSV se estableció a partir de tres medidas consecutivas del mismo párpado. La pérdida media de MG de los párpados superior (S1:13.5±9.5%, S2:12.8±8,5%, E1:12.7±8.2%, E2:13.1±8%) e inferior (S1:7.5±6.9%, S2:7.3± 6.3%, E1:7±6.2%, E2:7.4±6.2%) no fue significativamente diferente entre sesiones ni examinadores para todas las cohortes y para ambos párpados. Las desviaciones estándar (Sw) de la ISR intra sujeto para los párpados superior e inferior fueron 1.3 % y 1 %; la diferencia media (md) fue 0.7±3.5% y 0.1±2.1%, respectivamente. Los valores de IER ICC fueron >0.86 para todas las condiciones, la Sw 1.3% y 1.2% con md -0.4±3.2% y -0.4±2.9%, respectivamente. La Sw WSV <1.4 % y los valores de ICC >0.89 p, Postprint (published version)

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, examin, Peer Reviewed, Postprint (published version)

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., Peer Reviewed, Postprint (author's final draft)