Human saccadic eye movements and tracking by active foveation in log polar space

One of the possible models of the human visual system (HVS) in the computer vision literature has a high resolution fovea and exponentially decreasing resolution periphery. The high resolution fovea is used to extract necessary information in order to solve a vision task and the periphery may be used to detect motion. To obtain the desired information, the fovea is guided by the contents of the scene and other knowledge to position the fovea over areas of interest. These eye movements are called saccades and corrective saccades. A two stage process has been implemented as a mechanism for changing foveation in log polar space. Initially, the open loop stage roughly foveates on the best interest feature and then the closed loop stage is invoked to accurately iteratively converge onto the foveation point. The open loop stage developed for the foveation algorithm is applied to saccadic eye movements and a tracking system. Log polar space is preferred over Cartesian space as: (1) it simultaneously provides high resolution and a wide viewing angle; and (2) feature invariance occurs in the fovea which simplifies the foveation process.

Shared care for chronic eye diseases : perspectives of ophthalmologists, optometrists and patients

Objective: To report the perspectives of optometrists, ophthalmologists and patients on a model of shared care for patients with chronic eye diseases.

Design, setting and participants: Qualitative study of a model of shared care between optometrists and ophthalmologists for patients with stable age-related macular degeneration, diabetic retinopathy and glaucoma, trialled by the Royal Victorian Eye and Ear Hospital in Melbourne during 2007–2009. Semi-structured interviews were conducted with optometrists, ophthalmologists and patients at completion of the project to obtain their perspectives on this model.

Results: Seventeen optometrists submitted expressions of interest to participate, and 12 completed web-based training modules and clinical observerships and adhered to specified examination and reporting protocols. All five participating ophthalmologists and 11 of the optometrists were interviewed. Ninety-eight patients participated and 37 were interviewed. Optometrists not only met ophthalmologists’ expectations but exceeded them, appropriately detecting and referring patients with additional, previously undetected conditions. Patients reported savings in travel time and were satisfied with the quality of care they received. Optometrists, ophthalmologists and patients indicated a general acceptance of shared care arrangements, although there were some issues relating to interprofessional trust.

Conclusions: Shared care between local optometrists and hospital-based ophthalmologists can help to reduce patient waiting time for review and offers an opportunity for these two groups of eye care professionals to collaborate in providing localised care for the benefit of patients. However, trust and relationship building need to be further developed.

Visual impairment and eye care among Alaska native people

Purpose: To estimate the prevalence of visual impairment, eye disease and eye care in the Alaska Native (AN) population, by demographic and socioeconomic factors.

Methods: Population-based cross-sectional study of 3,793 AN adults aged 18–94 years enrolled in the Education and Research Towards Health (EARTH) Study from March 2004–March 2006. Data on self-reported visual impairment, cataract, glaucoma, diabetic eye disease and previous dilated eye examinations were collected using audio computer-assisted self-administered questionnaires.

Results: The unadjusted prevalence of self-reported visual impairment was 8.7% (95% confidence interval (CI): 7.9–9.7), cataract 5.9% (95% CI: 5.2–6.7), glaucoma 2.5% (95% CI: 2.0–3.0) and diabetic eye disease 1.3% (95% CI: 0.9–1.7). In all cases, age-sex adjusted prevalence estimates for the AN population were greater than available estimates for the general U.S. population. Prevalence of visual impairment and each eye disease increased with age (P < 0.01). Additional factors associated with visual impairment were education and annual household income. Overall, 70.0% (95% CI: 68.5–71.6) of participants reported a dilated eye examination within the previous two years. Dilated eye examination within the previous two years was associated with increasing age (P < 0.001). However, men and participants with lower formal education were less likely to report recent dilated eye examination. Among those with diabetes, only 67.7% (95% CI: 60.8–74.1) reported a dilated eye examination within the recommended previous one year.

Conclusions: Self-reported visual impairment, cataract, glaucoma and diabetic eye disease are prevalent in the AN population. These data may be useful in healthcare planning and education programs.

The eye

An oil painting in 2 panels on Cherrywood