Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Experiment Videos

Aphakic reading adds. An error in traditional teaching.

R K Maloney1, K M Miller, D L Guyton

  • 1Wilmer Ophthalmological Institute, Baltimore.

Ophthalmology
|August 1, 1989
PubMed
Summary

In aphakic spectacles, the effective bifocal add equals the prescribed add, not the back vertex power difference. This finding corrects traditional teaching and may improve vision for aphakic patients.

Related Concept Videos

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

Handling, infectious agents and physiological condition influence survival and post-release behaviour in migratory adult coho salmon after experimental displacement.

Conservation physiology·2020
Same author

Time spent outside of target glucose range for young children with type 1 diabetes: a continuous glucose monitor study.

Diabetic medicine : a journal of the British Diabetic Association·2020
Same author

The Transatlantic HbA<sub>1c</sub> gap: differences in glycaemic control across the lifespan between people included in the US T1D Exchange Registry and those included in the German/Austrian DPV registry.

Diabetic medicine : a journal of the British Diabetic Association·2019
Same author

Greater parental comfort with lower glucose targets in young children with Type 1 diabetes using continuous glucose monitoring.

Diabetic medicine : a journal of the British Diabetic Association·2019
Same author

Evidence of a hydraulically challenging reach serving as a barrier for the upstream migration of infection-burdened adult steelhead.

Conservation physiology·2019
Same author

Olfactory gene expression in migrating adult sockeye salmon Oncorhynchus nerka.

Journal of fish biology·2018

Area of Science:

  • Ophthalmic Optics
  • Spectacle Prescription
  • Visual Science

Background:

  • Traditional teaching in ophthalmic optics suggests the effective bifocal add in aphakic spectacles exceeds the prescribed add.
  • This is attributed to the reading segment being on the front lens surface, leading to greater back vertex power.
  • Current practice dictates measuring effective power at the back surface.

Purpose of the Study:

  • To clarify the true effective bifocal add in aphakic spectacles.
  • To challenge the traditional teaching regarding back vertex power measurements.
  • To inform practitioners about potential impacts on patient vision.

Main Methods:

  • Informal explanation of optical principles.
  • Analysis of effective add versus prescribed add in aphakic lens designs.
  • Comparison of theoretical effective add with back vertex power measurements.

Main Results:

  • The effective bifocal add in aphakic spectacles is precisely equal to the prescribed add.
  • The effective add is not determined by the difference in back vertex power between lens segments.
  • Traditional measurement methods may lead to inaccurate assessments.

Conclusions:

  • Practitioners adhering to traditional teaching may prescribe suboptimal aphakic spectacles.
  • Accurate understanding of effective bifocal add is crucial for optimal patient reading vision.
  • Re-evaluation of measurement techniques for aphakic spectacles is recommended.

Related Experiment Videos