Normal and diseased personal eye modeling using age-appropriate lens parameters.

Personalized eye modeling of normal and diseased eye conditions is attractive due to the recent availability of detailed ocular measurements in clinic environments and the promise of its medical and industrial applications. In the customized modeling, the optical properties of the crystalline lens including the gradient refractive index, the lens bio-geometry and orientation are typically assigned with average lens parameters from literature since typically they are not clinically available. Although, through the optical optimization by assigning lens parameters as variables, the clinical measured wavefront aberration can be achieved, the optimized lens biometry and orientation often end up at edges of the statistical distribution. Without an effective validation of these models today, the fidelity of the final lens (and therefore the model) remains questionable. To develop a more reliable customized model without detailed lens information, we incorporate age-appropriate lens parameters as the initial condition of optical optimization. A biconic lens optimization was first performed to provide a correct lens profile for accurate lower order aberration and then followed by the wavefront optimization. Clinical subjects were selected from all ages with both normal and diseased corneal and refractive conditions. 19 ammetropic eyes ( + 4D to -11D), and 16 keratoconus eyes (mild to moderate with cylinder 0.25 to 6D) were modeled. Age- and gender-corrected refractive index was evaluated. Final models attained the lens shapes comparable to the statistical distribution in their age.

Computer-based real-time analysis in mobile ocular screening.

Mobile ocular telemedicine is potentially an effective method to provide service in medically underserved areas and to screen large populations for abnormalities. Currently, digital images are acquired, stored, and transferred to readers for evaluation, after which the results are provided to the subjects. The transfer of large image files and the timeliness of the subsequent reading of images are significant factors for practical implementation of effective telemedicine screening. This work examines the feasibility of in situ real-time computer analysis of digital images to determine and classify the image results as normal and abnormal. This retrospective study used a photoscreening database of 360 patients ranging in ages from 6 months to 18 years. Computer analysis automatically classified the binocular photorefraction (PR) images, and these PR results were compared to those of the subjective clinical eye examinations provided. With an average processing time of approximately 15 seconds per examinee, the analysis found that the PR results can be categorized as: a positive group that requires referral (186 cases) with a predictive value of 98.9% (2 false-positives); a negative group (144 cases) with a predictive value of 89.6% (15 false-negatives); and an uncertain group (30 cases or 8.3%) that required resolution by readers. The real-time analysis code reduces by approximately 92% the manpower for image grading and electronic transmission at this stage of ocular evaluation. These results indicate the feasibility of this approach.

Simulation of keratoconus observation in photorefraction.

In the recent years, keratoconus (KC) has increasingly gained attention due to its treatment options and to the popularity of keratorefractive surgery. This paper investigates the potential of identification of KC using photorefraction (PR), an optical technique that is similar to objective retinoscopy and is commonly used for large-scale ocular screening. Using personalized eye models of both KC and pre-LASIK patients, computer simulations were performed to achieve visualization of this ophthalmic measurement. The simulations are validated by comparing results to two sets of experimental measurements. These PR images show distinguishable differences between KC eyes and eyes that are either normal or ametropic. The simulation technique with personalized modeling can be extended to other ophthalmic instrument developments. It makes possible investigation with the least number of real human subjects. The application is also of great interest in medical training.

Telehealth practice recommendations for diabetic retinopathy.

Telehealth holds the promise of increased adherence to evidenced-based medicine and improved consistency of care. Goals for an ocular telehealth program include preserving vision, reducing vision loss, and providing better access to medicine. Establishing recommendations for an ocular telehealth program may improve clinical outcomes and promote informed and reasonable patient expectations. This document addresses current diabetic retinopathy telehealth clinical and administrative issues and provides recommendations for designing and implementing a diabetic retinopathy ocular telehealth care program. The recommendations also form the basis for evaluating diabetic retinopathy telehealth techniques and technologies. Recommendations in this document are based on careful reviews of current evidence, medical literature and clinical practice. They do not, however, replace sound medical judgment or traditional clinical decision-making. "Telehealth Practice Recommendations for Diabetic Retinopathy" will be annually reviewed and updated to reflect evolving technologies and clinical guidelines.