Ophthalmic Lens Centering
Ophthalmic Lens Centering - Related Videos
03:14
Eye Lens Dissection: A Technique to Observe Zebrafish Lens Morphology
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2023
This video describes the protocol which is developed to dissect adult and larval zebrafish lenses to analyze cortical lens morphology and structural integrity of the lens sutures.
01:23
Ophthalmic Drug Delivery Systems
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2026
Ophthalmic drug delivery faces major limitations due to poor absorption across the corneal membrane. This process is primarily driven by diffusion and is influenced by two main factors: the physicochemical properties of the drug and tear drainage. Most ophthalmic drugs, such as pilocarpine, epinephrine, atropine, and local anesthetics, are weak bases. They are typically formulated at an acidic pH to enhance chemical stability. However, this leads to high ionization, reducing their ability to...
05:14
Simulating the Mechanics of Lens Accommodation via a Manual Lens Stretcher
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Cited by 9 •
2018
We present an efficient method of studying lens accommodation by using a manual lens stretcher. The protocol mimics physiological accommodation by pulling the zonules connected around the lens capsule, thereby, stretching the lens.
02:48
Developing Myopia in a Mouse Model Through Lens-Induced Defocusing
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2025
Source: Jiang, X., et al. Inducement and evaluation of a murine model of experimental myopia. J. Vis. Exp. (2019)This video demonstrates a procedure for inducing myopia in a mouse through the installation of a custom lens frame. The frame is secured to the exposed skull with dental adhesive, and concave lenses are inserted to shift the focal point behind the retina. This setup stimulates eyeball elongation leading to myopia.
02:33
Lattice Centering and Coordination Number
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2020
The structure of a crystalline solid, whether a metal or not, is best described by considering its simplest repeating unit, which is referred to as its unit cell. The unit cell consists of lattice points that represent the locations of atoms or ions. The entire structure then consists of this unit cell repeating in three dimensions. The three different types of unit cells present in the cubic lattice are illustrated in Figure 1. Types of Unit Cells Imagine taking a large number of identical...
FAQs
Decentration changes the point through which the wearer looks, so the eye may view through an area away from the lens’s optical center. According to Prentice’s rule, that offset can induce prism. Evaluating decentration therefore helps the dispenser anticipate unwanted prismatic effects and preserve the intended binocular relationship during wear.
Pupillary distance identifies the horizontal relationship between the wearer’s pupils and the lenses, while fitting height supplies the corresponding vertical placement information. Using both measurements allows lens positioning to reflect the wearer’s actual line of sight rather than relying on a generalized frame position. This is especially relevant when precise alignment is needed.
Prentice’s rule matters because it connects lens decentration with the possibility of induced prism when the wearer looks away from the optical center. In dispensing, this principle gives meaning to the measured offset: decentration is not merely a positioning discrepancy, but an optical factor that can affect binocular alignment and visual comfort.
Spectacle lenses function as a pair during binocular viewing, so positioning each lens appropriately helps maintain the relationship between the two visual axes. An error affecting one side can contribute to an altered prismatic relationship between the eyes. Considering both pupils supports binocular alignment, comfort, and consistent visual performance.
During dispensing, measurements guide lens placement rather than serving only as an after-the-fact check. Pupillary distance and fitting height establish the intended positioning, and decentration is then assessed in relation to that placement. This workflow connects the prescription, the frame fit, and the wearer’s visual axis during the fitting process.
The fitting process begins by using pupillary distance and fitting height to guide where each lens should sit. The dispenser then considers whether the lens position produces decentration relative to the wearer’s pupil and visual axis. This assessment helps identify unwanted prism and supports the intended optical performance of the eyewear.
Accurate positioning deserves particular attention with high-power, multifocal, and custom lenses. These applications depend on fitting the prescribed optical design appropriately to the wearer’s visual axis. Careful centering helps minimize unwanted prismatic effects while supporting visual performance, comfort, and adaptation during the use of corrective eyewear.