Publications

Showing 25 results out of 521 in total.

Efron,N., Morgan,P. B., Jones,L. W., Morgan,G. A., Nichols,J. J. Global optometrist top 200 research ranking Clinical and Experimental Optometry 2021;104(4):471-485 [ Show Abstract ]

Clinical relevance: Clinical optometric practice is underpinned by a rigorous research base, the
primary evidence for which is publications in refereed scientific journals. Leading optometrists who
publish this work should be identified and celebrated.
Background: This work aims to derive publication metrics of the leading optometric researchers
worldwide.
Methods: An extensive global search was conducted to discover leading optometric researchers; 480
names were identified. A custom-designed bibliographic search tool was developed to interrogate
the Scopus database (Elsevier) and extract publication metrics using the unique Scopus Author
Identifier number for each optometrist. On 13 January 2021, the full list was reduced to 200
optometrists (the ‘Top 200’) ranked by h-index – the ‘Global Optometrist Top 200 Research
Ranking’. The output from the custom tool automatically updates every 24 hours and is available at
www.optomrankings.com.
Results: The Top 200 have h-indices ranging from 20 to 67 and have published between 28 and 440
papers. Sixty one (30.5%) are women. Konrad Pesudovs has the highest h-index (67) and citations
(51,193). The most prolific author is Robert Hess (442 papers). David Piñero is publishing at the
fastest rate (17.6 papers per year). The Top 200 work in 13 nations, of whom 172 (86.0%) work in
four nations: USA – 76 (38.0%), Australia – 43 (21.5%), UK – 41 (20.5%) and Canada – 16 (8.0%). Of
the 72 institutions represented, the University of California, Berkeley, USA is home to the most Top
200 optometrists (17) and has the highest combined h-index of Top 200 optometrists (132).
Conclusions: The optometric profession is supported by a robust research base, prosecuted by
a large international cohort of optometric researchers who publish extensively on a broad range of
ophthalmic issues and whose work is highly cited. The 200 most impactful optometrists in the world
are identified

Efron,N., Morgan,P. B., Jones,L. W., Nichols,J. J. 21st century citation analysis of the field of contact lenses Clinical and Experimental Optometry 2021;104(5):634-638 [ Show Abstract ]

Clinical relevance: The scientific foundations for clinical contact lens practice are rooted in the ophthalmic literature. This analysis of contact lens papers celebrates contemporary research achievements in the contact lens field.

Background: This work aims to assemble contact lens-related publication metrics so as to identify the most impactful papers published so far this century, as well the top countries, authors, institutions and journals.

Methods: A search was undertaken of the titles of papers on the Scopus database to identify contact lens-related articles published this century. The ten most highly cited papers were determined from the total list of 4,164 papers found. Rank-order lists by count were assembled for the ‘top 25ʹ in each of four categories: authors, institutions, countries and journals. A 20-year subject-specific contact lens h-index (hCL-20-index) was derived for each author, institution, country and journal to serve as a measure of impact in the field. The top 10 constituents (of the top 25) of each category were ranked by hCL-20-index and tabulated for consideration.

Results: The most highly cited paper this century is entitled ‘Soft contact lens polymers: An evolution’, by Nicholson and Vogt. Lyndon Jones is the most impactful author, with a hCL-20-index of 32. The University of New South Wales (Australia) produces the most impactful contact lens-related papers, and the United States is the most highly-ranked country. Optometry and Vision Science is the most impactful journal in the contact lens field.

Conclusions: Contact lens materials and lens-associated keratitis are topics of high interest in the contemporary contact lens literature, with an emerging interest in orthokeratology for myopia control and glucose monitoring. Impactful 21st century authors, institutions, countries and journals are identified. Optometry is revealed as the leading profession in relation to the publication of impactful contact lens-related papers.

Efron,N., Morgan,P. B., Jones,L. W., Nichols,J. J. Bibliometric analysis of the refractive error field Clinical and Experimental Optometry 2021;104(5):641-643 [ Show Abstract ]

Research into the epidemiology, aetiology, and optics of ametropia is a fundamental cornerstone of the correction and management of refractive errors by eye care practitioners. At present, much of this work is driven by the clinical concern that myopia is a common cause of vision loss, with uncorrected myopia the leading cause of vision impairment globally. Holden et al. predict that by 2050, about 50% of the population of the world will be myopic.
The aetiology of myopia continues to be hotly debated, centring around the relative impact of nature (genetics) versus nurture (environment). Research aimed at optimising optical (spectacles and contact lenses) and surgical (laser refractive techniques) modes of correcting refractive error continues unabated, and novel approaches for arresting the progression of myopia, using ophthalmic lenses, contact lenses (including orthokeratology), pharmacological approaches, or lifestyle modification, are also under active investigation. As is the case in all fields of investigation, the foundation of these various lines of refractive error research is rooted in the ophthalmic literature. Modern bibliographic search tools enable targeted interrogation of this vast literature to facilitate identification of the research foundations that underpin our understanding of refractive error. This Viewpoint uses
these bibliographic search tools and employs a subjectspecific measure of impact to identify key papers, authors, institutions, countries, and journals in the field of refractive error research.

Efron,N., Morgan,P. B., Jones,L. W., Nichols,J. J. Bibliometric analysis of the keratoconus literature Clinical and Experimental Optometry 2021;21(Sep):1-6 [ Show Abstract ]

Clinical Relevance
Clinicians, researchers funding agencies and indeed the general public can benefit from knowledge of the most highly cited papers and most impactful authors, institutions, countries and journals in the field of keratoconus.

Background
Bibliometrics relating to the keratoconus literature were derived to enable identification of the most impactful papers published, as well as the leading authors, institutions, countries and journals.

Methods
A search was undertaken of the titles of papers on the Scopus database to identify keratoconus-related articles. The 20 most highly cited papers were determined from the total list of 4,419 papers found. Rank-order lists by count were assembled for the ‘top 20ʹ in each of four categories: authors, institutions, countries and journals. A subject-specific keratoconus-related h-index (hKC-index) was derived for each constituent of each category to serve as a measure of impact in the field. The top 10 constituents of each category were ranked by hKC-index and tabulated for consideration.

Results
The hKC-index of the keratoconus field is 125. The 4,419 papers have been cited a total of 98,010 times, and 18.5% of these papers have never been cited. The most highly cited paper is a general review of keratoconus by Yaron Rabinowitz, who is also the most impactful author in the field (hKC = 31). The Cedars Sinai Medical Center in the United States produces the most impactful keratoconus-related papers (hKC = 36), and the United States is the most impactful country (hKC = 91). The Journal of Cataract and Refractive Surgery is the most impactful journal (hKC = 55).

Conclusion
Keratoconus is a topic of high interest in the clinical and scientific literature. Highly cited papers and impactful authors, institutions, countries and journals are identified.

Efron,N., Morgan,P. B., Jones,L. W., Nichols,J. J. Bibliometric Analysis of the Emerging Field of Myopia Management Optometry & Vision Science 2021;98(9):1039-1044 [ Show Abstract ]

SIGNIFICANCE
Identification of the most impactful articles, authors, institutions, countries, and journals in myopia management provides a useful baseline reference for clinicians, researchers, and funding agencies in respect of this emerging field.

This work aims to assemble publication metrics for myopia management to identify the most impactful articles, authors, institutions, countries, and journals in this emerging field of research. A search of the titles of articles was undertaken on the Scopus database to identify myopia management–related articles. The 25 most highly cited articles were determined from the total list of 1064 articles found. Rank-order lists by count were assembled for the top 25 in each of four categories: authors, institutions, countries, and journals. A subject-specific myopia management–related h-index (hMM-index) was derived for the entire field, in addition to each of the four categories, to serve as measures of impact in the field. Top 15 lists were generated for each category ranked by hMM-index and tabulated for consideration. An article by Christine Wildsoet and colleagues, describing choroidal and scleral mechanisms of compensation for spectacle lenses in chicks, has generated the most citations (412); Earl Smith is the most impactful author (hMM = 19); the University of Houston produces the most impactful articles (hMM = 31); the United States is the most highly ranked country (hMM = 60); and Optometry and Vision Science is the most impactful journal. Although still in its infancy, myopia management is a topic of emerging interest in the clinical and scientific ophthalmic literature. Impactful authors, institutions, countries, and journals are identified. Optometry is revealed as the leading profession in relation to the publication of myopia management–related articles.

Efron,N., Morgan,P. B., Nichols,J. J., Walsh,K., Willcox,M. D., Wolffsohn,J. S. Jones,L. W. All soft contact lenses are not created equal Contact Lens Anterior Eye 2022;45(2):Article 101515 [ Show Abstract ]

Abstract
Soft contact lenses that have been prescribed by eye care practitioners are sometimes substituted for alternative lenses by unqualified, unregulated and sometimes even fully regulated lens suppliers, in the mistaken belief that there is essentially no difference between different soft lens types. This review considers the implications of inappropriately substituting soft contact lens types in terms of (a) lens properties: surface treatment, internal wetting agents, material, total diameter, back optic zone radius, thickness, edge profile, back surface design, optical design, power, colour (tint) and ultraviolet protection; and (b) lens usage: wearing modality (daily versus overnight wear) and replacement frequency. Potential aspects of patient dissatisfaction and adverse events when prescribed soft lenses are substituted for lenses with different properties or intended usage are considered. Substitution of 15 of the 16 lens properties considered (i.e. except for back surface design) was found to be related to at least one – and as many as six – potential sources of patient dissatisfaction and adverse ocular events. Contact lens are medical devices which are prescribed and fitted; they should never be substituted for another lens type in the absence of a new prescription further to a full finalised fitting, for the simple reason that all soft contact lenses are not created equal. A substituted lens may have properties that results in undesirable consequences in respect of vision, ocular health, comfort and cosmetic appearance, and may be incompatible with the lifestyle of the patient.

Efron,N., Morgan,P., Jones,L., Nichols,J. Who cites optometry journals? Journal of Optometry 2023;Online ahead of print [ Show Abstract ]

Purpose
This work seeks to identify the most impactful journals, papers, authors, institutions, and countries that cite optometry journal articles.

Methods
The Scopus database was searched for papers citing at least one article published in any of the 18 optometry journals included in that database (i.e. ‘optometry articles’). The 10 most highly cited papers that cite optometry journal articles were determined from 82,830 papers found. A h-index for “optometry journal citations” (the hOJC-index) was derived for each entity in the categories of journals, papers, authors, institutions and countries to serve as a measure of impact.

Results
The hOJC-index of the body of papers citing optometry journal articles is 370. Papers citing optometry journal articles have themselves been cited 2,054,816 times. Investigative Ophthalmology & Visual Science (hOJC = 154) is the most impactful journal citing optometry articles and Optometry and Vision Science the most prolific (5310 papers). The most impactful paper citing optometry journal articles (5725 citations) was published in Journal of Clinical Epidemiology. Ophthalmologist Seang Mei Saw (hOJC = 69) is the most impactful author and optometrist Nathan Efron is the most prolific (288 papers). Harvard University (hOJC = 127) is the most impactful and UNSW Sydney is the most prolific institution (1761 papers). The United States is the most impactful and prolific nation (hOJC = 313; 28,485 papers).

Conclusions
Optometry journal articles are cited extensively by optometrists, ophthalmologists, and vision scientists world-wide, as well as authors from a broad spectrum of non-ophthalmic research domains. This work confirms the utility and influence of optometry journals.

Elliott,D. B., Fonn,D., Flanagan,J., Doughty,M. Relative sensitivity of clinical tests to hydrophilic lens-induced corneal thickness changes Optometry and Vision Science 1993;70(12):1044-1048 [ Show Abstract ]

The relative sensitivity of the van den Berg Straylightmeter, slitlamp biomicroscopy, a modified optical pachometer, Bailey-Lovie logMAR visual acuity (VA), and two glare tests (The Brightness Acuity Tester used with 10% contrast VA and Pelli-Robson contrast sensitivity) to hydrophilic contact lens-induced edema was assessed in 19 subjects (mean age 25.9 +/- 4.5 years). After baseline assessments, subjects wore thick hydrogel lenses on one eye which was patched tightly for 3 h. Assessments were repeated at frequent intervals after lens removal to assess recovery. None of the pachometer measurements returned to baseline within the 2-h monitoring period, although the majority were within 2% of baseline corneal thickness. The average time for the Straylightmeter scores to recover to baseline values after the lens removal was 90 min, which was similar to the time when visible edema at the slitlamp disappeared. The average time for return to baseline of logMAR VA and the two glare tests was consistently two to three times shorter than the time for the Straylightmeter score. The Straylightmeter therefore provided assessments of corneal edema similar to slitlamp examination and was more sensitive than VA or glare testing.

Elliott,D. B., Situ,P. Visual acuity versus letter contrast sensitivity in early cataract Vision research 1998;38(13):2047-2052 [ Show Abstract ]

Large and small letter contrast sensitivity and visual acuity were assessed in 37 elderly eyes (mean VA -0.01 logMAR, Snellen 6/6) and their lens opacities were categorised and graded using the LOCS III system. Large letter contrast sensitivity was often not reduced in cataract from age-matched normal values and provided limited information. Small letter contrast sensitivity was shown to be a more sensitive measure of early cataract than visual acuity and large letter contrast sensitivity. Its usefulness may be limited by its strong correlation with visual acuity (r2 = 0.70), which is the standard and traditional measure of vision in cataract.

Elliott,D. B., Yang,K. C. H., Dumbleton,K., Cullen,A. P. Ultraviolet-induced lenticular fluorescence: Intraocular straylight affecting visual function Vision research 1993;33(13):1827-1833 [ Show Abstract ]

Ultraviolet radiation (UVR) excitation of fluorophores within the crystalline lens results in intraocular straylight. These fluorescent emissions are known to increase with age. The visual effect of this increase in fluorescent straylight has not previously been published. In this study, the visual deficit associated with UV-induced lenticular fluorescence was measured for 61 normal subjects between the ages of 21 and 80 yr of age using the Regan visual acuity charts at varying levels of contrast. UVR was shown to decrease low contrast acuity and this loss increased linearly with age.

Elliott,M., Fandrich,H., Simpson,T., Fonn,D. Analysis of the repeatability of tear break-up time measurement techniques on asymptomatic subjects before, during and after contact lens wear Contact Lens and Anterior Eye 1998;21(4):98-103 [ Show Abstract ]

This study assessed the repeatability of various methods of measuring tear break-up time (TBUT) with and without soft contact lenses (CLs).TBUT was measured on 22 subjects with the tearscope, videokeratoscope and slit-lamp before and after 30 min of soft CL wear, and immediately after CL removal. Slit-lamp corneal TBUT was measured with fluorescein and without fluorescein while wearing CLs. TBUT was measured three times on the right eye only, using each technique in randomised order. TBUT measurements on CLs were repeated a second day. TBUT measurements were highly variable under all conditions and our results indicated a lack of correlation between techniques. The videokeratoscope was the least repeatable; while the tearscope was the most repeatable technique.

Elliott,M., Simpson,T., Richter,D., Fonn,D. Repeatability and accuracy of automated refraction: A comparison of the Nikon NRK-8000, the Nidek AR-1000, and subjective refraction Optometry and Vision Science 1997;74(6):434-438 [ Show Abstract ]

This study assessed the repeatability of the Nikon NRK-8000, the Nidek AR-1000, and subjective refraction. In addition, the accuracy of the Nikon and the Nidek were evaluated in comparison to subjective refraction. Measurements were taken with all 3 techniques on 2 separate occasions with a test-retest separation of at least 24 h. The right eyes of 30 normal subjects were used. Repeatability and accuracy statistics and plots were generated using matrix representations of dioptric power. Subjective refraction was the most repeatable method, with the coefficient of repeatability (COR) found to be 0.611, 0.224, and 0.490 in the vertical, torsional, and horizontal meridians. The autorefractors' COR was found to range from 0.712 to 0.826 for the vertical and horizontal meridians, whereas the torsional meridian ranged from 0.224 to 0.319.

Elliott,M., Simpson,T., Richter,D., Fonn,D. Repeatability and comparability of automated keratometry: The Nikon NRK-8000, the Nidek KM-800 and the Bausch and Lomb keratometer Ophthalmic and Physiological Optics 1998;18(3):285-293 [ Show Abstract ]

This study assessed the repeatability of the Nikon NRK-8000, the Nidek KM-800 and the Bausch and Lomb keratometer. In addition, the comparability of the Nikon NRK-8000 and the Nidek KM-800 are evaluated relative to the Bausch and Lomb keratometer. Measurements were taken with all three techniques on two separate occasions with a test-retest separation of at least 24 hr. The right eyes of 30 normal subjects were used. Repeatability and comparability statistics and plots were generated using matrix representations of dioptric power. The Nidek KM-800 coefficient of repeatability values were found to be 0.345, 0.187, and 0.321 in the vertical, torsional, and horizontal meridians while the Nikon NRK-8000 values were 0.346, 0.232, and 0.276 respectively.

Fadel,D. Medmont Meridia™: Much More Than a Corneal Topographer Clinical Optometry 2023;15 283-301 [ Show Abstract ]

In recent years, advanced diagnostic instruments have become widely available in optometric practices, offering various functions that optimize clinical information gathering. This article focuses on the Medmont Meridia™, a state-of-the-art multipurpose diagnostic device with corneal topography and cutting-edge features. Corneal topography is pivotal in the early diagnosis of corneal disorders, determining baseline ocular surface assessment, helping in contact lens fitting, and monitoring ocular health over time. The Medmont Meridia boasts Placido-disc-based imaging with extensive corneal coverage. Furthermore, the Meridia accurately measures the horizontal visible iris diameter, pupil diameter, and palpebral fissure width, which assists in making contact lens parameter decisions. Additionally, it offers sagittal height data for scleral lens design and first lens selection, streamlining the fitting process. Beyond its topography capabilities, the Meridia excels as a comprehensive dry eye assessment tool. With features like tear meniscus height, tear film surface quality, and meibography capabilities, it aids in diagnosing dry eye and monitoring its progression. The device also provides customizable dry eye reports with integrated grading scales and questionnaires, making dry eye management, patient education, and compliance more accessible. In conclusion, the Medmont Meridia consolidates a multitude of examination tools in a single instrument, enhancing practice efficiency and elevating patient care and communication. Its versatility and accuracy make it an invaluable asset in optometric practices worldwide.

Fadel,D., Gildea,C. Case Report: Remote Scleral Lens Fitting for High Toric Scleras in a Keratoconus Patient Optometry and Vision Science 2023;100(12):876-881 [ Show Abstract ]

SIGNIFICANCE
Technology plays a crucial role in customizing scleral lenses and improving lens alignment, especially in challenging scleral shapes. In addition, remote fitting technology allows optometrists to extend their expertise globally, empowering patients to access to customized lenses without travel expenses.

PURPOSE
The objective of this study was to document the difficulties encountered in fitting a scleral lens in a patient with keratoconus and pronounced scleral toricity. In addition, the study aimed to present the successful remote fitting achieved by using advanced technology.

CASE REPORT
An Irish male patient diagnosed with keratoconus exhibited high scleral toricity. Generally, keratoconus eyes often exhibit significant scleral asymmetry associated with cone decentration and disease severity. Improperly aligned scleral lenses can lead to regional changes in scleral shape, lens decentration, discomfort, and visual disturbances. Indeed, previous scleral lens fits were unsuccessful because of these issues. Corneoscleral profilometry was acquired in Ireland and then used in Italy to design customized lenses, which were then delivered to the patient's optometrist in Ireland. The first lenses designed and delivered demonstrated excellent overall performance without requiring adjustments.

CONCLUSIONS
This report highlights the importance of corneoscleral profilometry to increase efficiency and reduce lens reorders and chair time, and the remote fitting in overcoming barriers to accessing specialized lens fitting.

Fadel,D., Macedo-de-Araújo,R. J., Barnett,M. The Patient-Physician Relationship and Role of Empathic Communication in Contact Lens Practice Journal of Contact Lens Research and Science 2024;8(1):20-36

Feng,Y., Simpson,T. L. Nociceptive sensation and sensitivity evoked from human cornea and conjunctiva stimulated by CO2 Investigative Ophthalmology and Visual Science 2003;44(2):529-532 [ Show Abstract ]

PURPOSE. To compare sensation and sensitivity evoked from human cornea and conjunctiva stimulated by CO2. METHODS. Twenty healthy participants were recruited for the study. Central corneal and temporal conjunctival chemical sensation and sensitivity of only one eye of each subject were evaluated. Air mixed with different concentrations of CO2 was delivered by a modified Belmonte pneumatic esthesiometer. The ascending method of limits was used to determine the sensitivity and subjects were required to characterize the sensation at threshold. RESULTS. The sensations evoked by CO2 in the cornea and conjunctiva were stinging or burning. The sensation evoked by mechanical stimulation was that of irritation. The corneal and conjunctival chemical thresholds were 31% ± 2% and 54% ± 5% CO2 (mean ± SE), respectively. The corneal and conjunctival mechanical thresholds were 80 ± 6 and 140 ± 10 mL/min (mean ± SE), respectively. The corneal sensitivity was significantly higher for both mechanical and chemical stimuli (P < 0.05). CONCLUSIONS. The results suggest that CO2 stimulates similar corneal and conjunctival nociceptors in that the interpretations were the same (i.e., nociceptive). The central cornea had a higher sensitivity to CO2 than the temporal conjunctiva, which may reflect a different peripheral innervation, such as different nerve density or different receptor characteristics. Sensations evoked by mechanical and chemical stimulation were different, which suggests that at the peripheral level, the two modalities stimulate two different kinds of molecular receptors or channels and that this information is somehow retained within the nociceptive system.

Feng,Y., Simpson,T. L. Comparison of human central cornea and limbus in vivo using optical coherence tomography Optometry and Vision Science 2005;82(5):416-419 [ Show Abstract ]

Purpose. The purpose of this study was to compare central corneal and limbal total and epithelial thickness using a commercially available optical coherence tomographer. Methods. A Humphrey-Zeiss Optical Coherence Tomographer (OCT [Carl Zeiss, Meditec, Dublin, CA]) was used to obtain corneal images from 10 subjects. Central corneal and limbal total and epithelial thickness of both eyes were measured using the OCT. Each OCT image comprised 100 measurements, 10 nasal, 10 central, and 10 temporal measurements from each image were analysed. Results. The central corneal and epithelial thickness of the right and the left eyes were 507.9 ± 35.8 μm, 58.4 ± 2.5 μm, 506.9 ± 37.4 μm, and 58.5 ± 2.5 μm, respectively. There were no differences between eyes (p > 0.05). The nasal and temporal limbal total and epithelial thickness of the right and left eyes were 703.8 ± 32.1 μm, 704.9 ± 31.0 μm, 76.8 ± 3.5 μm, 77.9 ± 2.9 μm, 704.4 ± 31.8 μm, 706.3 ± 32.5 μm, 77.5 ± 2.8 μm, and 77.8 ± 2.5 μm, respectively. There were no differences between the nasal and temporal total and epithelial thickness of both eyes (p > 0.05). However, there was a statistical difference between the central corneal and limbal total and epithelial thickness (both p < 0.05). Conclusions. Central cornea and limbus are measurably different using OCT. Central cornea is thinner than limbus for both total thickness and epithelial thickness. There is no difference between eyes of central corneal and limbal total and epithelial thickness. Optical Coherence Tomography is a useful instrument for in vivo human limbal morphometry. Copyright © 2005 American Academy of Optometry.

Feng,Y., Simpson,T. L. The inhibitory interaction between human corneal and conjunctival sensory channels Investigative Ophthalmology and Visual Science 2005;46(4):1251-1255 [ Show Abstract ]

PURPOSE. To explore human corneal and conjunctival sensory channels at suprathreshold level. METHODS. Ten healthy human subjects participated in the study. The Belmonte pneumatic esthesiometer was used to apply mechanical and chemical stimuli to the central cornea and temporal conjunctiva of the left eye. Stimuli were applied in a paired and unpaired way for conjunctival stimulation. A 100-point visual analog scale (VAS) was used to rate the intensity of the stimulus. RESULTS. The magnitudes of the sensation evoked from the conjunctiva were different when using different methods for presenting stimuli to the ocular surface. When stimuli were applied to the conjunctiva alone, the magnitude of the sensation was stronger than when the stimuli were applied in pairs to the cornea and conjunctiva for both mechanical (P = 0.04) and chemical (P = 0.02) stimulation. CONCLUSIONS. The relatively strong discomfort evoked from the cornea appears to suppress partially the relatively weaker conjunctival stimulation. This manifested as the conjunctival sensory transducer function being shallower (less intense sensation) when immediately preceded by corneal stimulation than when the conjunctival sensory transducer functions were measured alone (unpaired). The underlying mechanism could be adaptation or some other inhibitory effect, such as diffuse noxious inhibitory control. At some level therefore, corneal and conjunctival sensory channels are not independent. Copyright © Association for Research in Vision and Ophthalmology.

Feng,Y., Varikooty,J., Simpson,T. L. Diurnal variation of corneal and corneal epithelial thickness measured using optical coherence tomography Cornea 2001;20(5):480-483 [ Show Abstract ]

PURPOSE: To determine the feasibility of optical coherence tomography (OCT) measurement of overnight corneal swelling and de-swelling and, specifically, to examine overnight changes in the corneal epithelium and recovery during the day. METHODS: Ten healthy volunteers were recruited. Corneal OCT imaging was performed at 10:00 PM (baseline), 8:30 AM, and every 2 hours thereafter until 4:30 PM. Either the right or left eye was taped shut (using a gauze pad and surgical tape) until the 8:30 AM session of the next day. Measurements were made along a 1-mm strip centered on the visual axis. RESULTS: At baseline, there were no differences in corneal or epithelial thickness between control and experimental eyes (all p > 0.05). Immediately after patch removal, corneal and epithelial thicknesses of patched eyes were higher than the baseline (all p < 0.05). In patched eyes, the cornea and epithelium swelled 5.5% and 8.1% overnight, respectively (p > 0.05). Two hours later, the epithelial thickness of the experimental eyes recovered to baseline level (p > 0.05), but corneal thickness did not reach to baseline level until 4 hours after patch removal. For control eyes, there were no differences compared with baseline (all p > 0.05). CONCLUSION: Both cornea and corneal epithelium experience proportionately similar amounts of overnight swelling. Recovery of overnight swelling may be slower for the cornea than for the epithelium. OCT provides valuable information about anterior segment morphometry.

Fieguth,P., Simpson,T. Automated measurement of bulbar redness Investigative Ophthalmology and Visual Science 2002;43(2):340-347 [ Show Abstract ]

PURPOSE. To examine the relationship between physical image characteristics and the clinical grading of images of conjunctival redness and to develop an accurate and efficient predictor of clinical redness from the measurements of these images. METHODS. Seventy-two clinicians graded the appearance of 30 images of redness on a 100-point sliding scale with three referent images (at 25, 50, and 75 points) through a World Wide Web-based survey. Using software developed in a commercial computer program, each image was quantified in two ways: by the presence of blood vessel edges, based on the Canny edge-detection algorithm, and by a measure of overall redness, quantified by the relative magnitude of the redness component of each red-green-blue (RGB) pixel. Linear and nonlinear regressors and a Bayesian estimator were used to optimally combine the image characteristics to predict the clinical grades. RESULTS. The clinical judgments of the redness images were highly variable: The average grade range for each image was approximately 55 points, more than half the extent of the entire scale. The median clinical grade was chosen as the most reliable measure of "truth." The median grade was predicted by a weighted linear combination of the edgeness and redness features of each image. The strength of the predicted association was r = 0.976, exceeding the strength of association of all but one of the 72 individual clinicians. CONCLUSIONS. Clinical grading of redness images is highly variable. Despite this human variability, easily implemented image-analysis and statistical procedures were able to reliably predict median clinical grades of conjunctival redness.

Fonn,D. Editorial: Myopia control and new editorial board members Eye and Contact Lens 2010;36(4):189

Fonn,D. It's a new day Eye and Contact Lens 2010;36(3):139

Fonn,D. Just what do we mean by clinical significance Eye and Contact Lens 2010;36(1):1

Fonn,D. Editorial: Concerned parents and patients Eye and Contact Lens 2010;36(2):67