The "Expected Visual Outcome" (EVO) model: methodology and clinical validation.

V Lakshminarayanan; A J Lang; V Portney

Home/Archive/PubMed

PubMed · 8539016

The "Expected Visual Outcome" (EVO) model: methodology and clinical validation.

V Lakshminarayanan·A J Lang·V Portney

View original source ↗Export metadata ↓

Abstract

PROBLEM: If changes are made to the optics of the eye (e.g., intraocular lens implants, contact lenses, etc.) how will they affect performance on clinical tests of vision? METHOD: A phenomenological method is presented based on in vitro optical transfer function (OTF) and a simple model of human threshold detection. RESULTS: The model is used to predict and the results are compared with clinical data (acuity, contrast sensitivity) obtained from pseudophakic patients implanted with a multifocal intraocular lens (IOL). A good qualitative agreement is found with the clinical data. SIGNIFICANCE: This model predicts the relative change in clinical performance for a given change in the optical components of the human eye. This simple phenomenological model permits numerical prediction of clinical tests and is easily calculable.

Explore related subjects

Cataract Extraction Contrast Sensitivity Humans Lenses, Intraocular Models, Biological Pupil Reproducibility of Results Sensory Thresholds Vision, Ocular Visual Acuity Comparative Study Journal Article Research Support, Non-U.S. Gov't

Keep this discovery

Explore connections, maps & timelines

BibTeX RIS

V Lakshminarayanan, A J Lang, V Portney. 1995. The "Expected Visual Outcome" (EVO) model: methodology and clinical validation.. https://pubmed.ncbi.nlm.nih.gov/8539016/

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed2007

Profile of clear corneal cataract incisions demonstrated by ocular coherence tomography.

PURPOSE: To examine the profile of clear corneal cataract incisions in the living eye using optical coherence tomography (OCT). SETTING: Private practice, Eugene, Oregon, USA. METHODS: The Zeiss Visante OCT anterior segment imaging system was used to study the profile of clear corneal cataract incisions, all in senior citizens. The OCT images of the operative eye were taken on the first postoperative day approximately 24 hours after surgery. The OCT images of clear corneal incisions were compared with an OCT image of a control eye, incisions without stromal hydration, and previous drawings of clear corneal incisions. RESULTS: In the images, the clear corneal incisions had an arcuate configuration rather than a straight line configuration, as previously indicated. This architecture appears to add greater stability as a result of a tongue-and-groove-like fit of the floor to the roof of the incision as well as an incision that is longer than the chord length that had previously been measured. Other findings include that stromal swelling, which facilitates sealing of these incisions by the endothelial pump, lasted for at least 24 hours. CONCLUSIONS: Results indicate an incision in the plane of the cornea with a chord length of at least 2.0 mm provides advantageous architecture for adequate self-sealing. Proper clear corneal incision construction resulted in an incision architecture that seemed to have increased stability and added safety, contributing to an absence of endophthalmitis for more than 10 years and 9000 cases in a single practice.

Cataract Extraction↗

PubMed2007

Indocyanine green toxicity.

Explore the source record for details and available documents.

Cataract Extraction↗

PubMed2007

Teaching and assessing competence in cataract surgery.

PURPOSE OF REVIEW: To review recent literature regarding innovative techniques, methods of teaching and assessing competence and skill in cataract surgery. RECENT FINDINGS: The need for assessment of surgical competency and the requirement of wet lab facilities in ophthalmic training programs are being increasingly emphasized. Authors have proposed the use of standardized forms to collect objective and subjective data regarding the residents' surgical performance. Investigators have reported methods to improve visualization of cadaver and animal eyes for the wet lab, including the use of capsular dyes. The discussion of virtual reality as a teaching tool for surgical programs continues. Studies have proven that residents trained on a laparoscopic simulator outperformed nontrained residents during actual surgery for both surgical times and numbers of errors. Besides virtual reality systems, a program is being developed to separate the cognitive portion from the physical aspects of surgery. Another program couples surgical videos with three-dimensional animation to enhance the trainees' topographical understanding. SUMMARY: Proper assessment of surgical competency is becoming an important focus of training programs. The use of surgical data forms may assist in standardizing objective assessments. Virtual reality, cognitive curriculum and animation video programs can be helpful in improving residents' surgical performance.

Cataract Extraction↗