Related Experiment Video
Updated: Jan 3, 2026
05:14
Simulating the Mechanics of Lens Accommodation via a Manual Lens Stretcher
Published on: February 23, 2018
7.2K
Optical Coherence Tomography Reveals Sigmoidal Crystalline Lens Changes during Accommodation.
George A Gibson1, Fiona E Cruickshank1, James S Wolffsohn1
1Ophthalmic Research Group, Life and Health Sciences, Aston University, Birmingham B4 7ET, UK.
Vision (Basel, Switzerland)
|November 19, 2019
Summary
During accommodation, significant biometric changes occur in the anterior segment, primarily driven by the anterior lens surface initially, then the posterior lens surface, showing a sigmoidal response.
Area of Science:
- Ophthalmology
- Biomedical Optics
- Anatomy
Background:
- Accommodation is a crucial visual process involving dynamic changes in the anterior segment.
- Understanding these biometric shifts is vital for accurate refractive error correction and ophthalmic device design.
Purpose of the Study:
- To quantify anterior segment biometric modifications during accommodation.
- To compare these changes with accommodative demand and response.
- To investigate the role of anterior and posterior lens surfaces in accommodation.
Main Methods:
- AS optical coherence tomography (AS-OCT) captured anterior segment images in 30 adults (18-25 years) under stimulated accommodation (0-4 D).
- Lens thickness (LT), anterior chamber depth (ACD), lens centroid, and anterior segment length (ASL) were measured.
- Accommodative responses were recorded using an autorefractor; data were compared with Dubbelman schematic eye models.
Main Results:
- Significant changes in LT, ACD, lens centroid, and ASL occurred with accommodation (p < 0.01).
- Corneal thickness (CT) showed no significant change (p = 0.81).
- AS-OCT measurements of LT and ASL were higher than Dubbelman model predictions. The posterior lens surface exhibited a sigmoidal response pattern.
Conclusions:
- Accommodation induces significant biometric alterations in the anterior segment, particularly in lens dimensions and anterior chamber depth.
- The anterior lens surface is the primary driver of accommodation up to ~1.5 D response, after which the posterior lens surface contributes significantly.
- The posterior crystalline lens surface demonstrates a sigmoidal response to increasing accommodative effort.
More Related Videos
07:56Sequential Application of Glass Coverslips to Assess the Compressive Stiffness of the Mouse Lens: Strain and Morphometric Analyses
Published on: May 3, 2016
7.6K
07:44In vivo Structural Assessments of Ocular Disease in Rodent Models using Optical Coherence Tomography
Published on: July 24, 2020
3.3K
Related Concept Videos
01:16Focusing of Light in the Eye
5.1K
Light rays enter the eye through the cornea, a transparent dome-shaped tissue that is the eye's outermost layer. The cornea bends or refracts, light rays traveling to the pupil. The shape of the cornea determines how much of the light is bent and whether the image will be focused correctly on the retina at the back of the eye. Once the light has passed through both refraction layers, it converges into a single focal point onto a small area. This is where photoreceptors start transforming...
5.1K
01:28Angle Closure Glaucoma: Treatment
1.1K
Angle-closure glaucoma, or closed-angle glaucoma, is an eye condition where the iris bulges out and blocks the iridocorneal angle, resulting in a buildup of aqueous humor and increased intraocular pressure. Immediate medical attention is necessary due to the sudden onset of symptoms. The treatment for angle-closure glaucoma includes short-term and long-term approaches. Short-term treatment involves using eye drops like pilocarpine to lower intraocular pressure by increasing aqueous humor...
1.1K
01:05Mechanism of Ciliary Motion
4.7K
The ciliary structures were first seen in 1647 by Antonie Leeuwenhoek while observing the protozoans. In lower organisms, these appendages are responsible for cell movement, while in higher organisms, these appendages help in the movement of the extracellular fluids within the body cavities.
The cilia are made up of microtubules in a 9+2 arrangement, with nine microtubule doublet ring bundles, surrounding a pair of central singlet microtubule bundles. The doublet microtubule bundles are...
The cilia are made up of microtubules in a 9+2 arrangement, with nine microtubule doublet ring bundles, surrounding a pair of central singlet microtubule bundles. The doublet microtubule bundles are...
4.7K
01:25Glaucoma: Overview
1.2K
Glaucoma is an eye condition characterized by increased intraocular pressure that damages the retina and optic nerve, leading to irreversible blindness if left untreated. The human eye has various components, including the cornea, iris, pupil, lens, and optic nerve. Aqueous humor is secreted by the epithelium of the ciliary body in the posterior chamber and flows through the trabecular meshwork and canal of Schlemm, maintaining normal intraocular pressure. The trabecular meshwork and the canal...
1.2K
01:27Open Angle Glaucoma: Treatment
909
In open-angle glaucoma, the iridocorneal angle remains open, but the trabecular meshwork becomes stiff, slowing down the outflow of aqueous humor. This causes a buildup of aqueous humor in the anterior chamber, leading to a sudden increase in intraocular pressure. The treatment for open-angle glaucoma focuses on reducing the elevated intraocular pressure by either decreasing the secretion of aqueous humor or increasing its outflow.
Drugs such as carbonic anhydrase inhibitors, α2- and...
Drugs such as carbonic anhydrase inhibitors, α2- and...
909