Peter R. Keller

The relation between corneal and total astigmatism

Using computer-assisted videokeratoscopy we measured corneal astigmatism and compared these results over a range of corneal zone diameters with total ocular astigmatism derived by subjective refraction. Videokeratoscopes permit a more detailed analysis of the power distribution within a given corneal surface area, enabling comparison to the total astigmatism for equivalent aperture sizes. Although there were significant individual variations, the group average data supports the traditional view of a linear relation between corneal and total astigmatism. This was true across the range of apertures tested from 2 to 7 mm, with the coordinates of the relation being consistent with that of the modified Javals rule; namely a slope of 1 and an intercept of approximately 0.50 D against-the-rule residual astigmatism.

An Evidence-Based Analysis of Australian Optometrists' Dry Eye Practices

Purpose The aims of this study were to investigate the clinical practices of Australian optometrists as related to the diagnosis, quantification, and management of dry eye and to assess whether these are consistent with research evidence and current guidelines. Methods An online survey was distributed to registered optometrists (n = 654). Respondents provided information regarding their preferred diagnostic procedures and management strategies for dry eye, practice modality, year of commencing practice, and whether they possessed an interest in dry eye. Results Respondents (n = 144) used multiple procedures for diagnosis. Recording patient symptoms ranked as the most important, most valuable, and most commonly used technique. The main objective tests were fluorescein-assisted tear breakup time, corneal fluorescein staining, and meibomian gland evaluation. Optometrists with an interest in dry eye more frequently used lissamine green, phenol red test, interference fringes, and tear osmolarity than nonspecialist practitioners. Dry eye treatment varied with severity. The mainstay of therapy was nonpreserved lubricants and eyelid hygiene; more practitioners recommended topical corticosteroids, systemic omega-3 fatty acid supplementation and increased dietary intake of omega-3 fatty acids for moderate and severe disease, respectively. The primary sources of information used to guide practitioners’ management were derived from continuing education conferences. Conclusions This study indicates that although Australian optometrists use subjective and objective diagnostic tests and stratify treatment based on dry eye severity, there is a lack of uniformity regarding diagnostic testing, infrequent use of standardized grading scales, and significant variability in clinical care. These findings highlight the potential to improve the translation of dry eye research evidence and evidence-based guidelines into Australian optometric practice.

Fourier analysis of corneal topography data after photorefractive keratectomy

Purpose: To evaluate the relation between measures of corneal power and refractive error after photorefractive keratectomy (PRK) by applying fast Fourier transform (FFT) to computerized corneal topography data. Setting: Corneal Diseases and Excimer Laser Ginic, Sunderland Eye Infirmary, Sunderland, England, and University of Dundee Department of Ophthalmology, Dundee, Scotland. Methods: Twenty‐six left eyes of consecutive patients treated by PRK with a VISX Twenty‐Twenty excimer laser were retrospectively analyzed. Preoperative and 3, 6, and 12 month postoperative data were studied. Changes in corneal parameters derived from corneal topography data using the FFT were compared with changes in refractive status vectors (spherical equivalent and astigmatic cosine and sine values). Result: Although highly correlated (r2 = 0.8839), the change in FFT‐derived corneal spherical equivalent underestimated the change in refractive spherical equivalent by 25.5% over the 12 month follow‐up. Decentration, measured by the 1‐cycle FFT harmonic, increased significantly from a mean preoperative value of 0.12 mm ± 0.07 (SD) to 0.51 ± 0.35 mm 12 months postoperatively. Conclusions: The FFT is a powerful method for extracting clinically meaningful descriptors from corneal topography data; however, care must be taken when interpreting refractive changes from corneal data.

Nutrition and Age-Related Macular Degeneration: Research Evidence in Practice

Age-related macular degeneration (AMD) is the leading cause of irreversible visual impairment in developed countries. In the absence of effective treatments to slow AMD progression, it is predicted that the prevalence of AMD will double over the next 20 years. One area of significant interest is the potential role that nutrition may play in preventing and/or delaying the progression of AMD. Specifically, is there any benefit in oral antioxidant and/or mineral supplementation? This review critically evaluates the currently available evidence relating to nutrition and AMD, with particular reference to the key findings of two large National Eye Institute-sponsored clinical studies, namely, the Age-Related Eye Disease Study (AREDS) and AREDS2. Topical controversies relating to nutrition and AMD are considered and analyzed in the context of the published literature to guide practitioners through assessing the merit, or otherwise, of common claims. This article provides a foundation for clinicians to provide informed advice to AMD patients based on available research evidence.

A Pragmatic Approach to Dry Eye Diagnosis: Evidence into Practice.

ABSTRACT Dry eye disease (DED) is a common, multifactorial disease of the tears and anterior ocular surface. The clinical diagnosis of DED is complex, requiring the consideration of both patient symptoms and signs, which can be apparently contradictory. Misdiagnosis can lead to suboptimal clinical management. Studies of the practice behaviors of optometrists suggest that there is the potential to improve the translation of research evidence relating to the diagnosis of DED into primary ophthalmic care. This review describes an evidence-based, pragmatic approach to the contemporary clinical diagnosis of DED, as a means for guiding best practice for the care of dry eye patients.

A Pragmatic Approach to the Management of Dry Eye Disease: Evidence into Practice

ABSTRACT Dry eye disease (DED) is a highly prevalent chronic ocular disorder that can lead to significant discomfort and visual disturbance. It is a potentially debilitating condition that can have significant negative impact on quality of life. A diverse range of management options exists for DED, including tear supplement products, anti-inflammatory agents, immunomodulators, punctal occlusive devices, and environmental modifiers. Although the availability of a variety of treatment approaches provides clinical flexibility and can enable individualized care, it can also complicate clinical management decisions and lead to variability in the nature of the clinical care provided to patients. By considering two dry eye case scenarios, this review evaluates the currently available evidence relating to DED therapy to describe a pragmatic clinical approach to best-practice management of dry eye patients.

The evidence in evidence-based practice. Why the confusion?

In a scenario set to be played out across the country with increasing frequency over the coming years, an optometrist discusses the management options available to an elderly patient diagnosed with highrisk, early age-related macular degeneration (AMD). The patient is 73 years old, a smoker and a first-generation Australian of Mediterranean descent. Clinical examination of the patient has revealed the presence of multiple large drusen and pigmentary abnormalities all within 1,500 microns of the foveae. Visual acuity is R 6/7.5 and L 6/9.5. The patient asks what her risks are of losing her sight, and whether she should take one of the dietary supplements marketed for preserving macular health. To answer the patient’s questions appropriately demands that the optometrist understand the natural history of agerelated macular degeneration, specifically the risk of progression to advanced AMD, the evidence for the safety and efficacy of various approved and experimental treatments for the condition and importantly, the relevance of that evidence, as it is applied to this patient. In short, an evidence-based approach to the practice of optometry. Yet, there is sufficient anecdotal evidence to suggest reluctance among some optometrists to embrace evidencebased practice (EBP) and the question should be asked, why? The answer may well be found in a lack of understanding of EBP and what constitutes evidence, which I address in this article.

Assessing ocular bulbar redness: a comparison of methods

We consider whether quantification of ocular bulbar redness, using image processing of relative Red‐channel activity (Red‐value), can be applied to a clinical sample and how this approach compares to an automated bulbar redness grading technique (Oculus Keratograph 5M, R‐scan).

Comparing self-reported optometric dry eye clinical practices in Australia and the United Kingdom: Is there scope for practice improvement?

The aim of this study was to compare the self‐reported clinical practice behaviours of optometrists in Australia and the United Kingdom (UK) with respect to the diagnosis and management of dry eye disease (DED). We also sought to examine whether the reported practices of clinicians in each region were consistent with current evidence‐based recommendations for DED.

The Self-Reported Clinical Practice Behaviors of Australian Optometrists as Related to Smoking, Diet and Nutritional Supplementation

Objective The primary aim of this study was to examine the self-reported, routine clinical practice behaviors of Australian optometrists with respect to advice regarding smoking, diet and nutritional supplementation. The study also sought to assess the potential influence of practitioner age, gender, practice location (major city versus regional), therapeutic-endorsement status and personal nutritional supplementation habits upon management practices in these areas. Methods A survey was electronically distributed to Australian optometrists (n = 4,242). Respondents anonymously provided information about their personal demographics and lifestyle behaviors (i.e., age, gender, practice location, therapeutic-endorsement status, smoking status, nutritional supplement intake) and routine patient management practices with respect to advice across three domains: smoking, diet and nutritional supplementation. Multivariate logistic regression analyses were performed to assess for potential effects of the listed factors on practitioner behavior. Results A total of 283 completed surveys were received (completed survey response rate: 6.7%). Fewer than half of respondents indicated routinely asking their patients about smoking status. Younger practitioners were significantly (p < 0.05) less likely to enquire about patients’ smoking behaviors, but this did not extend to counseling for smoking cessation. Almost two-thirds of respondents indicated routinely counseling patients about diet. About half of practitioners specified routinely asking their patients about nutritional supplement intake; this form of questioning was significantly more likely if the respondent was female (p < 0.05). Practitioners who recommended nutritional supplements most commonly did so for age-related macular degeneration (91.2%) and dry eye disease (63.9%). The primary source of evidence used to guide practitioners’ nutrition-related patient management was reported to be peer-reviewed publications. Conclusions These findings demonstrate that there are no clear predictors of practitioner behavior across the three domains. Overall, this study suggests that there is scope for Australian optometrists to improve their routine engagement by questioning patients, as well as providing evidence-based clinical advice, about smoking status, diet and nutritional supplement behaviors, being key modifiable lifestyle risk factors with long-term implications for eye health.