Research outputs

@article{Durakovic2023,

title = {Mental Health Impact of Keratoconus: A Systematic Review},

author = {Emily Durakovic and Himal Kandel and Stephanie L. Watson},

doi = {10.1097/ico.0000000000003263},

issn = {0277-3740},

year  = {2023},

date = {2023-00-00},

journal = {Cornea},

volume = {42},

number = {9},

pages = {1187–1197},

publisher = {Ovid Technologies (Wolters Kluwer Health)},

abstract = {Purpose: The aim of this study was to investigate the impact of keratoconus on the mental health and emotional well-being of affected patients. Methods: A literature search was conducted according to the PRISMA guidelines. Databases searched included MEDLINE, PubMed, EMBASE, Scopus, Web of Science, Cochrane, and PsycINFO. Articles were included if they were a primary study that investigated mental health or emotional quality-of-life outcomes in patients with keratoconus. Results: Thirty-one articles met inclusion criteria of a total yield of 444. Most studies reported keratoconus to have a negative effect on mental health or emotional well-being. Worsening mental health scores correlated with lower visual acuity (VA) in the better eye, lower VA in the worse eye, increasing ocular asymmetry, and worsening disease severity. Mental health impacts were often reported to be disproportionate to that of the effects on VA. Over time mental health outcomes improved, suggesting stabilization of disease and patient acceptance. Conclusions: Patients with keratoconus may suffer detriments to mental health despite having relatively good VA. Understanding and acceptance of their disease may assist in assuaging mental health concerns. Further work may be needed to investigate whether benefit exists in routine mental health screening of patients with keratoconus.},

keywords = {Cornea, Fight Corneal Blindness},

pubstate = {published},

tppubtype = {article}

}

@article{Kandel2022,

title = {Cross-Linking Improves the Quality of Life of People With Keratoconus: A Cross-Sectional and Longitudinal Study From the Save Sight Keratoconus Registry},

author = {Himal Kandel and Jern Yee Chen and Srujana Sahebjada and Elaine W. Chong and Steven Wiffen and Stephanie L. Watson},

doi = {10.1097/ico.0000000000003185},

issn = {0277-3740},

year  = {2023},

date = {2023-00-00},

journal = {Cornea},

volume = {42},

number = {11},

pages = {1377–1383},

publisher = {Ovid Technologies (Wolters Kluwer Health)},

abstract = {Purpose: The purpose of this study was to comprehensively evaluate the patient-reported quality-of-life (QoL) outcomes after corneal cross-linking for keratoconus. Methods: This Save Sight Keratoconus Registry study used cross-sectional and longitudinal designs. For the cross-sectional study, 532 patients with keratoconus (mean age 30.9 ± 11.9 years; 31.6% female) completed the Keratoconus Outcomes Research Questionnaire (KORQ) and 343 patients with keratoconus (mean age 28.3 ± 10.7 years; 32.7% female) completed the Impact of Vision Impairment (IVI) questionnaires. Similarly, for the longitudinal study, 39 patients (mean age 24.2 ± 8.4 years; 23.1% female) completed the KORQ and 16 patients (mean age 27.9 ± 17.1 years; 50.0% female) completed the IVI questionnaire before and after 6 months of cross-linking. The QoL data were analyzed using the Andrich Rating Scale Model of Rasch analysis. Results: For both cross-sectional and longitudinal studies, the KORQ and IVI scales demonstrated satisfactory psychometric properties [ordered and well-spaced categories, variance explained by the measure 52%–73%, person separation index 2.4–3.9, and fit statistics <1.3 (most cases)]. The patients who had not undergone corneal cross-linking had worse mean activity limitation than those with cross-linking ( P = 0.008). However, the differences in symptoms and emotional scores between the groups were not statistically significant (both P > 0.05). The longitudinal study showed that cross-linking was associated with improved activity limitation, symptoms, and emotional scores. Conclusions: The KORQ and IVI are psychometrically robust tools to evaluate the QoL outcomes of corneal cross-linking. Cross-linking is associated with improved activity limitation, symptoms, and emotional status.},

keywords = {Cornea, Fight Corneal Blindness},

pubstate = {published},

tppubtype = {article}

}

@article{Kandel2022b,

title = {Patient-Reported Outcomes in Keratoconus: A Save Sight Keratoconus Registry Study},

author = {Himal Kandel and Konrad Pesudovs and Vuong Nguyen and Jern Yee Chen and Alexander Poon and Richard Mills and Stephanie L. Watson},

doi = {10.1097/ico.0000000000003119},

issn = {0277-3740},

year  = {2023},

date = {2023-00-00},

journal = {Cornea},

volume = {42},

number = {5},

pages = {590–597},

publisher = {Ovid Technologies (Wolters Kluwer Health)},

abstract = {Purpose: The aim of this study was to evaluate the quality-of-life (QoL) status in keratoconus severity subgroups using the Keratoconus Outcomes Research Questionnaire (KORQ) and to determine the relationship between the QoL scores and the standard clinical variables. Methods: A cross-sectional study was conducted using prospective, web-based Save Sight Keratoconus Registry data. Rasch analysis was conducted on the KORQ data using the Andrich Rating Scale Model. Comparative analysis included Welch t test and 1-way ANOVA. Associations between visual acuity, corneal curvature, and minimum corneal thickness with KORQ scores were evaluated with Pearson correlation and multiple regression adjusted for age and sex. Results: The KORQ was completed by 542 patients with keratoconus (male, 67.7%; mean age, 31.6 years). Keratoconus severity, based on Kmax, was mild [<48 diopter (D)], moderate (48–55 D), and severe (>55 D) in 26.3%, 45.0%, and 28.7% of patients, respectively. Activity limitation (AL) and symptoms (SY) scales of the KORQ had robust psychometric properties including well-functioning response categories, unidimensionality, excellent measurement precision, and satisfactory fit statistics. In a group-wise analysis, the female patients had significantly lower AL and SY scores. Similarly, the severe keratoconus group had the worst AL and SY scores. Contact lens wearers had worse KORQ scores than the spectacles wearers. Overall, statistically significant but weak correlations between KORQ scores and visual acuity and corneal curvature (Kmax and K2) (Pearson r, 0.11–0.35) were observed. The correlations for SY were weaker than for AL scores. Conclusions: Female sex, contact lens wear, reduced visual acuity, and higher disease severity were associated with worse AL and SY scores in keratoconus. Although the correlations between clinical and QoL scores were statistically significant, the low magnitudes suggested a complex relationship between clinical parameters and patient-reported outcomes.},

keywords = {Cornea, Fight Corneal Blindness},

pubstate = {published},

tppubtype = {article}

}

@article{Benito-Pascual2022,

title = {Efficacy and Safety of Standard Corneal Cross-Linking Procedures Performed With Short Versus Standard Riboflavin Induction: A Save Sight Keratoconus Registry Study},

author = {Blanca Benito-Pascual and Himal Kandel and Marco Abbondanza and Richard Mills and Laurence Sullivan and Stephanie L. Watson},

doi = {10.1097/ico.0000000000003058},

issn = {0277-3740},

year  = {2023},

date = {2023-00-00},

journal = {Cornea},

volume = {42},

number = {3},

pages = {326–331},

publisher = {Ovid Technologies (Wolters Kluwer Health)},

abstract = {Purpose: The objective of this study was to compare the effectiveness and safety of short versus standard riboflavin induction times in cross-linking (CXL) for keratoconus. Methods: A retrospective comparative study was conducted with data from the Save Sight Keratoconus Registry. Inclusion criteria were epithelium-off technique, standard UVA CXL protocol (3 mW/cm 2 for 30 minutes), riboflavin induction for 15 minutes (short) or 30 minutes (standard), and 1 year of follow-up data after CXL. Outcome measures included changes in best-corrected visual acuity (BCVA), keratometry in the steepest meridian (K2), maximum keratometry (Kmax), thinnest pachymetry (TCT), and adverse events. Analysis was conducted using mixed-effects regression models adjusted for age, sex, visual acuity, keratometry, pachymetry, practice, and eye laterality. Results: Two hundred eighty eyes (237 patients; mean, 27.3 ± 10.5 years old; 30% female) were included. The riboflavin induction time was short in 102 eyes (82 patients) and standard in 178 eyes (155 patients). The baseline characteristics (sex, mean age, BCVA, keratometry, and pachymetry [TCT]) were similar between the groups. At the 1-year follow-up visit, no statistically significant differences were observed in flattening in K2 and improvement in BCVA. Greater Kmax flattening [−1.5 diopters (D) vs. −0.5D},

keywords = {Cornea, Fight Corneal Blindness},

pubstate = {published},

tppubtype = {article}

}

@article{Khoo2022,

title = {Clinical Registries in Dry Eye Disease: A Systematic Review},

author = {Pauline Khoo and Laura E. Downie and Fiona Stapleton and Saaeha Rauz and Vincent Daien and Francisco Arnalich and David Mingo and Stephanie L. Watson},

doi = {10.1097/ico.0000000000003139},

issn = {0277-3740},

year  = {2022},

date = {2022-00-00},

journal = {Cornea},

volume = {41},

number = {12},

pages = {1572–1583},

publisher = {Ovid Technologies (Wolters Kluwer Health)},

abstract = {Purpose: The objective of this study was to undertake a systematic review of the literature reporting on clinical registries in dry eye disease (DED). Methods: Electronic searches were conducted using systematic review methodology to provide an overview of clinical registries in ophthalmology and to identify clinical registries reporting on dry eye parameters. Two reviewers independently assessed titles and abstracts, then full-texts for eligibility. Results: A total of 129 clinical registries in ophthalmology were identified. The most common conditions captured were blindness or low vision, followed by glaucoma and corneal transplantation. Most of the registries originated in Europe (n = 56), followed by North America (n = 28). Of the registries identified, 12 were multinational, 59 were national, and 17 were regional. The second search identified 27 eligible articles, from which 8 clinical registries reporting on dry eye parameters were identified. One registry included patients with a diagnosis of dry eye. The remaining 7 registries included patients from a nationwide administrative ophthalmic database (n = 1), Sjögren syndrome (n = 4), glaucoma (n = 1), or were monozygotic and dizygotic twins (n = 1), who were evaluated for DED. Five of the registries were actively collecting data. Conclusions: Most of the registries identified in this review evaluated aqueous deficient dry eye; however, the most common type of dry eye in the general population is evaporative. Few registries also collected recommended dry eye clinical assessment. A well-designed clinical registry for DED that engages international eye care clinicians has the potential to vastly contribute to addressing pivotal gaps in understanding this highly prevalent disease.},

keywords = {Cornea, Fight Corneal Blindness},

pubstate = {published},

tppubtype = {article}

}

@article{Kandel2021b,

title = {Comparative Efficacy and Safety of Standard Versus Accelerated Corneal Crosslinking for Keratoconus: 1-Year Outcomes From the Save Sight Keratoconus Registry Study},

author = {Himal Kandel and Vuong Nguyen and Alex C. Ferdi and Aanchal Gupta and Marco Abbondanza and Laurence Sullivan and Andrew Apel and Stephanie L. Watson},

doi = {10.1097/ico.0000000000002747},

issn = {0277-3740},

year  = {2021},

date = {2021-00-00},

journal = {Cornea},

volume = {40},

number = {12},

pages = {1581–1589},

publisher = {Ovid Technologies (Wolters Kluwer Health)},

abstract = {Purpose: The aim of this study was to compare the efficacy and safety of standard [Ultraviolet (UV) light power: 3 mW/cm 2 , duration: 30 minutes] versus accelerated (UV power: 9 mW/cm 2 , duration: 10 minutes) corneal crosslinking (CXL) for stabilizing keratoconus. Methods: A total of 684 eyes (555 patients; mean age ± SD, 25.0 ± 7.9 years; women, 30.6%) from 24 international sites with epithelium-off CXL for keratoconus had follow-up data at 1-year and met the inclusion criteria. Two hundred sixty-six eyes (228 patients) had undergone standard CXL, and 418 eyes (327 patients) had undergone accelerated CXL. The outcome measures included changes in visual acuity, keratometry, minimum corneal thickness, and frequency of adverse events. The outcomes were compared using mixed-effects regression models adjusted for age, sex, visual acuity, keratometry, pachymetry, doctor, practice, and eye laterality. Results: The adjusted mean changes (95% confidence interval) in outcomes were similar in standard and accelerated CXL in visual acuity [6.5 (2.0, 11.1) versus 5.5 (0.4, 10.6) logMAR letters, respectively], Kmax [−0.9 (−1.4, −0.3) D versus −1.2 (−1.9, −0.4) D, respectively], K2 [−0.4 (−0.9, 0.2) D versus −0.4 (−1.1, 0.3), D respectively], or minimum corneal thickness [−13.3 (−20.3, −6.3) μm versus −16.6 (−24.5, −8.6) μm, respectively] (all P > 0.05). The frequency of adverse events at the 12-month visit was also similar between the CXL groups (standard, 8.3% vs. accelerated, 5.5%; P = 0.21). Conclusions: This real-world observational study found that both standard and accelerated CXL were similarly safe and effective in stabilizing keratoconus at 1-year postsurgery in the real-world setting. The findings support the adoption of accelerated CXL for time and convenience.},

keywords = {Cornea, Fight Corneal Blindness},

pubstate = {published},

tppubtype = {article}

}

@article{Ferdi2019,

title = {The Impact on Work Patterns of Implementing the Save Sight Keratoconus Registry in the Hospital Setting},

author = {Alex C. Ferdi and Vuong Nguyen and Chameen Samarawickrama and Alex Hamilton and Season Yeung and Stephanie L. Watson},

doi = {10.1097/ico.0000000000002159},

issn = {0277-3740},

year  = {2020},

date = {2020-00-00},

journal = {Cornea},

volume = {39},

number = {4},

pages = {451–456},

publisher = {Ovid Technologies (Wolters Kluwer Health)},

abstract = {Purpose: The adoption of clinical registries has the potential to improve outcomes, while reducing the costs of health care. We sought to evaluate the changes in workflow that occurred with implementation of the Save Sight Keratoconus Registry (SSKR) in corneal clinics. Methods: A prospective time–motion study and a clinician survey were conducted. The timing of clinic consultations was recorded before and after implementation of the SSKR. The activities were assigned into 3 main categories: 1) direct patient care (eg, talking to, examining), 2) indirect patient care (record keeping), and 3) indirect patient care (reading). Results: Overall, there was no change in average time spent per patient with or without the SSKR; 12.3 (5.3 SD) versus 12.1 (5.3 SD) minutes, respectively},

keywords = {Cornea, Fight Corneal Blindness},

pubstate = {published},

tppubtype = {article}

}

@article{Kandel2019,

title = {Psychometric Properties of the Keratoconus Outcomes Research Questionnaire: A Save Sight Keratoconus Registry Study},

author = {Himal Kandel and Konrad Pesudovs and Alex Ferdi and Richard Mills and Jern Yee Chen and Adam Watson and Alexander Poon and Laura E. Downie and Stephanie L. Watson},

doi = {10.1097/ico.0000000000002169},

issn = {0277-3740},

year  = {2020},

date = {2020-00-00},

journal = {Cornea},

volume = {39},

number = {3},

pages = {303–310},

publisher = {Ovid Technologies (Wolters Kluwer Health)},

abstract = {Purpose: The aim of this study was to evaluate the psychometric properties of the Keratoconus Outcomes Research Questionnaire (KORQ) in patients enrolled in the Save Sight Keratoconus Registry. Methods: A cross-sectional study was conducted utilizing prospectively collected web-based registry data. The psychometric properties of the KORQ were assessed using both classical test theory and Rasch analysis. Andrich group rating scale variant of the Rasch analysis was conducted using Winsteps software, Version 3.92.1. Results: The KORQ was completed by 189 patients with keratoconus (men, 67.7%; white, 69.8%; median age 29 years; better eye median values: visual acuity, 75 LogMAR letters; Kmax, 51.3 D; K2, 46.5 D; thinnest pachymetry, 485 μm). Cronbach's α for the “Activity Limitation” and “Symptoms” scales were 0.95 and 0.91, respectively, with both scales free from floor or ceiling effects. On Rasch analysis, the category thresholds were ordered and well-spaced for both scales. The Activity Limitation scale had excellent psychometric properties including person separation index (3.6), unidimensionality (variance explained, 65.4%), fit statistics (<1.3 MnSq), and measurement range (3.6 logits). Similarly, the Symptoms scale had satisfactory psychometric properties including person separation index (2.5), unidimensionality (variance explained, 54.3%), fit statistics (<1.30 MnSq except for 1 item), and measurement range (2.0 logits). Both scales were well targeted to the population and free of differential item functioning. Conclusions: The KORQ is a psychometrically robust patient-reported outcome measure for evaluating quality of life parameters in keratoconus. It enables routine collection and monitoring of meaningful patient-reported outcome data in clinical settings, including registries.},

keywords = {Cornea, Fight Corneal Blindness},

pubstate = {published},

tppubtype = {article}

}

@article{Kandel2019b,

title = {Measurement of Quality of Life in Keratoconus},

author = {Himal Kandel and Konrad Pesudovs and Stephanie L. Watson},

doi = {10.1097/ico.0000000000002170},

issn = {0277-3740},

year  = {2020},

date = {2020-00-00},

journal = {Cornea},

volume = {39},

number = {3},

pages = {386–393},

publisher = {Ovid Technologies (Wolters Kluwer Health)},

abstract = {Purpose: To identify and assess the quality of questionnaires used to measure quality of life in keratoconus and guide selection of the most appropriate questionnaire for evaluating the impact of keratoconus. Methods: A literature search was carried out in Scopus, Web of Science, PubMed, MEDLINE, Cochrane, and PsycINFO databases. Articles that described a questionnaire to measure quality of life in keratoconus were included. Information on psychometric properties and validity was extracted and analyzed based on a set of quality criteria. Finally, the impact of keratoconus and its management methods on quality of life was reviewed. Results: The search yielded 331 publications, of which 45 articles describing 18 (12 ophthalmic including 2 keratoconus-specific and 6 generic) questionnaires were reviewed. Most of the articles (40, 88.9%) described ophthalmic questionnaires not specific to keratoconus. The National Eye Institute Visual Function Questionnaire was the most frequently used questionnaire (n = 26). Only 4 articles provided information on psychometric properties. The Keratoconus Outcomes Research Questionnaire, the only validated keratoconus-specific questionnaire, had the most superior psychometric properties. However, it consists of items on only 2 domains of quality of life (activity limitation and symptoms). Overall, keratoconus management methods (spectacles, contact lenses, and cross-linking in early stages, corneal transplantation in late stages) improved quality of life. The quality of life scores were associated with clinical measures including visual acuity, corneal topography, pachymetry, and keratoconus severity. Conclusions: There is a need for a comprehensive and high-quality patient-reported outcome measure in keratoconus. A questionnaire should be chosen based on the purpose and the quality of the questionnaire. This review guides selection of an appropriate questionnaire.},

keywords = {Cornea, Fight Corneal Blindness},

pubstate = {published},

tppubtype = {article}

}

@article{Tan2019,

title = {Vision-Related Quality of Life in Keratoconus: A Save Sight Keratoconus Registry Study},

author = {Jeremy C. K. Tan and Vuong Nguyen and Eva Fenwick and Alex Ferdi and Amanda Dinh and Stephanie L. Watson},

doi = {10.1097/ico.0000000000001899},

issn = {0277-3740},

year  = {2019},

date = {2019-00-00},

journal = {Cornea},

volume = {38},

number = {5},

pages = {600–604},

publisher = {Ovid Technologies (Wolters Kluwer Health)},

abstract = {Purpose: To assess vision-related quality of life using the Impact of Vision Impairment Questionnaire (IVI) in patients with keratoconus enrolled in the Save Sight Keratoconus Registry. Methods: In this cross-sectional study, data on 107 keratoconic patients were collected through a prospectively designed web-based registry from a quaternary referral eye hospital and 2 corneal subspecialty practices. Vision-related quality of life was evaluated using the IVI. Rasch analysis was used to transform the IVI responses into interval-level measures comprising reading, mobility, and emotional well-being subscales. Associations between best-corrected visual acuity (BCVA), maximum simulated keratometry (Kmax), steep keratometry (K2), and pachymetry for each eye and IVI subscale scores were evaluated with univariate (Pearson correlations) and multivariable regression adjusted for age and gender. Results: Of the 107 patients, 37 (34.5%), 41 (38.0%) and 29 (26.9%) had mild, moderate, and severe keratoconus, respectively. On uni- and multivariable analysis, BCVA in the better eye had the strongest association with reading [r = 0.51; 95% confidence interval (CI), 0.35–0.64},

keywords = {Cornea, Fight Corneal Blindness},

pubstate = {published},

tppubtype = {article}

}