Related Experiment Video
Updated: Jun 14, 2026
05:46
Correction of Presbyopia by Monocular Bi-Aspheric Ablation Profile
Published on: September 20, 2024
Inverse Bell Phenomenon and Superior Keratoconus
Despoina Theotoka1, Brittany Perzia2, Taylor J Linaburg3
1Bascom Palmer Eye Institute, Miami, FL.
Cornea
|June 12, 2026
Summary
Superior keratoconus, a rare condition, was found to co-occur with the inverse Bell phenomenon in four patients. This association suggests mechanical pressure during eye closure may contribute to keratoconus development.
Area of Science:
- Ophthalmology
- Corneal Diseases
- Ocular Motility
Background:
- Keratoconus is a progressive thinning of the cornea, leading to irregular astigmatism.
- The inverse Bell phenomenon, characterized by downward globe rotation during eye closure, is an uncommon finding.
- The etiology of keratoconus is multifactorial, with mechanical factors proposed.
Purpose of the Study:
- To describe the clinical presentation of superior keratoconus.
- To investigate the association between superior keratoconus and the inverse Bell phenomenon.
- To explore potential pathomechanisms in keratoconus development.
Main Methods:
- Retrospective chart review of patients diagnosed with keratoconus.
- Analysis of patient demographics, clinical findings, and Pentacam corneal tomography.
- Identification of cases with superior corneal steepening and inverse Bell phenomenon.
Main Results:
- Four patients (6 eyes) with superior keratoconus were identified.
- All identified patients exhibited the inverse Bell phenomenon.
- Associated factors included sleeping positions involving eye pressure and floppy eyelid syndrome in some cases.
Conclusions:
- Superior keratoconus and inverse Bell phenomenon can co-occur, representing rare ophthalmic conditions.
- The inverse Bell phenomenon may increase mechanical stress on the superior cornea during lid closure.
- This finding supports the hypothesis that mechanical pressure plays a role in the pathogenesis of keratoconus.
Related Concept Videos
01:16Focusing of Light in the Eye
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...
01:25Glaucoma: Overview
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...
01:28Angle Closure Glaucoma: Treatment
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...
01:17Accessory Structures of the Eye
Optical perception, or vision, is an extraordinary sense dependent on converting light signals received via the ocular organs. These organs, known as eyes, are securely positioned within the bony cavities of the skull, called orbits. The orbits serve a dual purpose: a protective shield for the ocular globes and a stable attachment point for the soft ocular tissues. The eye's external protective mechanisms include the eyelids, which are edged with lashes that act as a barrier against foreign...
01:27Open Angle Glaucoma: Treatment
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...