Fallibility of Optometric Patients Recall of Spectacle Prescription Changes

AbstractPurposePractising optometrists and vision researchers often rely on the patient's recollection of past optometric events to compile a refractive history. The work reported here attempted to evaluate the reliability of such an approach in a clinical population by comparing self-report of previous spectacle prescription change against actual recorded refractive details.MethodsA documented healthy clinical population with mildmoderate myopia habitually corrected by spectacles was invited to complete a short tick-box questionnaire. Subjective recall of spectacle prescription changes over the past five years was investigated. Subsequently, these recollections were compared against individual recorded optometric histories.Results155 persons (42% of those canvassed: mean age 36.2± 9.1 years) responded to the invitation to complete the questionnaire. The subjective estimate of the interval since the most recent sight test was accurate (P=0.7). However the question “Has your distance glasses prescription been changed over the past five years?” had a sensitivity of 0.67/specificity of 0.64, and a positive predictive value (PV) of 0.43/negative PV of 0.82. With a calculated value of K= 0.25, the strength of the agreement between subjective recall and the actual record could at best only be regarded as “Fair”.ConclusionsThe accuracy of subjective recollection as an indication of refractive change over an immediately-preceding time interval of several years must be treated with caution. Whether questioning patients in the optometric practice or establishing the background of participants in a clinical vision research project, there is no substitute for reference to a contemporary record detailing refractive history

Visual performance of the human eye with soft hydrophilic contact lenses

The recording of visual acuity using the Snellen letter chart is only a limited measure of the visual performance of an eye wearing a refractive aid. Qualitative in addition to quantitative information is required to establish such a parameter: spatial, temporal and photometric aspects must all be incorporated into the test procedure. The literature relating to the correction of ametropia by refractive aids was reviewed. Selected aspects of a comparison between the correction provided by spectacles and contact lenses were considered. Special attention was directed to soft hydrophilic contact lenses. Despite technological advances which have produced physiologically acceptable soft lenses, there still remain associated with this recent form of refractive aid unpredictable visual factors. Several techniques for vision assessment were described, and previous studies of visual performance were discussed. To facilitate the investigation of visual performance in a clinical environment, a new semi-automated system was described: this utilized the presentation of broken ring test stimuli on a television screen. The research project comprised two stages. Initial work was concerned with the validation of the television system, including the optimization of its several operational variables. The second phase involved the utilization of the system in an investigation of visual performance aspects of the first month of regular daily soft contact lens wear by experimentally-naive subjects. On the basis of the results of this work an ‘homoeostatic’ model has been proposed to represent the strategy which an observer adopts in order to optimize his visual performance with soft contact lenses

Border distinctness in amblyopia

AbstractOn the basis of the contrast sensitivity loss in amblyopia which mainly affects higher spatial frequencies, one would expect amblyopes to perceive sharp edges as blurred. We show that they perceive sharp edges as sharp and have veridical edge blur perception. Contrary to the currently accepted view, this suggests that the amblyopic visual system is not characterized by a blurred visual representation

Recognition versus Resolution: a Comparison of Visual Acuity Results Using Two Alternative Test Chart Optotype

Purpose: To quantify the difference between recognition (letter) and resolution (Landolt) visual acuity (VA) in a group of normally sighted subjects. Is it reasonable to assume that the two acuity measures are clinically equivalent? Methods: A pair of 6 m acuity test charts was produced: one comprised letters and the other Landolt broken rings. Construction of both charts conformed to the logMAR design format. Monocular VA was determined for the dominant eye of 300 screened and normally sighted optometric patients aged 16 to 40, each wearing an optical refractive (spectacle) correction. Results: Letter acuity was superior to Landolt acuity (P≤0.0001). The mean paired acuity difference was -0.041 logMAR (standard deviation 0.034): the 95% limits of agreement were ±0.067 logMAR units or ±3.3 chart optotype. Repeatability was high and similar for each chart type (±2.1 and ±2.4 optotype for letter and Landolt, respectively). Gender, test sequence, and laterality of the dominant eye (left or right) were each non-statistically significant variables. Conclusions: For normally sighted subjects wearing an optimal refractive correction, a bias was recorded in favour of recognition over resolution acuity: the clinical difference amounted to approximately 40% of one logMAR chart line, with similar high repeatability for either chart optotype. We conclude that the assumption of clinical equivalence between letter and Landolt acuity is reasonable under optimum test conditions

Sighting versus sensory ocular dominance

Purpose: An indication of the laterality of ocular dominance (OD) informs the clinical decision making process when considering certain ophthalmic refractive and surgical interventions. Can predictive reliance be assured regardless of OD technique or is the indication of a dominant eye method-dependent? Methods: Two alternative OD test formats were administered to a group of 72 emmetropic healthy young adult subjects: the ‘hole-in-card’ test for sighting dominance and the ‘+1.50D blur’ test for sensory dominance. Both techniques were chosen as being likely familiar to the majority of ophthalmic clinicians; to promote and expedite application during the examination routine neither test required specialist training nor equipment. Results: Right eye dominance was indicated in 71% of cases by the sighting test but in only 54% of subjects using the sensory test. The laterality of OD indicated for the individual subject by each technique was in agreement on only 50% of occasions. Conclusions: Reasons are considered for the poor intra-individual agreement between OD tests, along with an item of procedural advice for the clinician

The primary eye care examination: Opening the case history and the patient's uninterrupted initial talking time

Purpose: The uninterrupted initial talking time (UITT) of optometric patients was measured in response to the clinician's opening question: “Do you have any problems with your eyes or your sight?” Methods: UITT was measured surreptitiously by the optometrist. Also noted was whether an eye/sight problem was claimed by the patient and whether or not this was subsequently confirmed by the examination. Results: Data were collected from 822 adults, mean age 59.1 yrs (SD 17.6), range 16.0–92.0 yrs. UITT data were positively skewed; median value 28.87 s (IQR 19.81–43.03 s) and no statistically significant difference between genders (p = 0.9). 53% of patients had completed their opening statement by 30 s, and 90% after 1 min. 75% of these individuals (age range 26–75 yrs) had a median UITT 27.82 s; younger patients (16–25 yrs) spoke for a significantly shorter time (18.39 s: p = 0.002) and elderly patients (≥76 yrs) a significantly longer time (37.27 s: p = 0.003) than the majority value. Previously unexamined patients, habitual spectacle wearers, and individuals presenting with an eye/sight problem all recorded a significantly longer UITT (p ≤ 0.006) than their peers. The practitioner's opening question had a sensitivity of 0.54/specificity of 0.95, and a positive predictive value (PV) of 0.78/negative PV of 0.87: with a calculated value of κ = 0.53, the strength of agreement between subjective claim and objective outcome could be regarded as ‘moderate’. Conclusion: These data suggest that an optometric patient's UITT of <30 s is unlikely to prove disruptive to the clinical routine

Navigating the Collagen Jungle: The Biomedical Potential of Fiber Organization in Cancer

Recent research has highlighted the importance of key tumor microenvironment features, notably the collagen-rich extracellular matrix (ECM) in characterizing tumor invasion and progression. This led to great interest from both basic researchers and clinicians, including pathologists, to include collagen fiber evaluation as part of the investigation of cancer development and progression. Fibrillar collagen is the most abundant in the normal extracellular matrix, and was revealed to be upregulated in many cancers. Recent studies suggested an emerging theme across multiple cancer types in which specific collagen fiber organization patterns differ between benign and malignant tissue and also appear to be associated with disease stage, prognosis, treatment response, and other clinical features. There is great potential for developing image-based collagen fiber biomarkers for clinical applications, but its adoption in standard clinical practice is dependent on further translational and clinical evaluations. Here, we offer a comprehensive review of the current literature of fibrillar collagen structure and organization as a candidate cancer biomarker, and new perspectives on the challenges and next steps for researchers and clinicians seeking to exploit this information in biomedical research and clinical workflows