The cornea is the is the clear, dome-shaped surface that covers the front of the eye. Although it may look clear and simple, the cornea is actually a highly organized tissue.
Unlike most tissues in the body, the cornea doesn't contain blood vessels, but rather receives its nourishment from tears and the aqueous humor.
The main role of the cornea is a protection. Along with the sclera (the white of the eye), the cornea works as a barrier against dirt, infections, and other things that may cause damage.
Beside protective role, the cornea can also filter out some of the sun's ultraviolet light, and it plays a key role in focusing your vision, helping determine how well the eye can focus on objects close-up and far away.
If a cornea is damaged by injury, disease, or an infection, the resulting scars may affect the vision by blocking or distorting the light as it enters the eye.
The term corneal disease refers to many conditions that affect this part of the eye, which may range from injuries to infections to congenital disorders.
Injury to the cornea due to trauma happens very often and it is usually repaired naturally and relatively quickly. However, an ophthalmologist needs to rule out other conditions that may present with similar symptoms.
Other conditions that may affect cornea include bacterial, fungal, or viral infections, as well as parasitic diseases, exposure to toxic chemicals, dystrophies and degenerative corneal disorders, such as Fuchs' dystrophy, map-dot-fingerprint dystrophy, or lattice corneal dystrophy, autoimmune disorders, such as rheumatoid arthritis, lupus, or Wegener's disease, growths, thinning, and more.
Certain nutritional deficiencies, such as vitamin A deficiency can affect the cornea, as well as seasonal allergies affecting more people each year.
The cornea can also be damaged secondarily by other eye conditions such as dry eye, eyelid disorders, glaucoma, and iridocorneal endothelial syndrome (ICE), which may be associated with glaucoma.
Given the large number of possible diseases and disorders that can affect the eye, it's no wonder that there is an entire medical subspecialty dedicated to the cornea and external diseases that require up to 5 years of residency and a full year or two of fellowship training to attain a proficiency.
There are many textbooks and atlases with images of corneal pathology that future and current ophthalmologists and cornea sub-specialists may use, but one of the most important is certainly Cornea Atlas that is available as a textbook and several mobile apps.
The Cornea Atlas app we review today is developed by Vision Institute, Department of Ophthalmology, Federal University of Sao Paulo. The app features an extensive collection of cornea and external disease pathology, covering 108 diseases and conditions classified into 16 categories.
The app primarily serves as a free educational and teaching resource for future generations of ophthalmologists.
Cornea Atlas doesn't require users to register an account. It opens straight to the simply organized main page that features 3 sections, including Preface, Content, and Credits.
Preface and Credit contain information about the app and the institution that supported it, as well as the intention behind the app.
The Content section is, of course, the core of Cornea Atlas app. It is an index of the different corneal conditions grouped in sections.
For example, there are Eyelid and Ocular Surface Disorders, including hordeolum, chalazion, dry eye, rosacea, and more. Next, there are viral infections, such as adenoviral keratoconjunctivitis, molluscum contagiosum, herpes, and so on, microbial and parasitic infections, including bacterial keratitis, blepharitis, Mycobacterium, and more.
Besides infections, the app also includes immune-related disorders, neoplastic disorders of the eye (benign and malignant lesions and growths), congenital abnormalities, metabolic disorders, conjunctival degenerations, corneal dystrophies, corneal epithelial deposits, ectatic disorders, corneal degenerations, toxic and traumatic injuries, corneal surgeries, and couple of syndromes that don't belong in any section listed.
Each section contains related conditions with a thumbnail image of their presentation in the eye. Tapping on a condition would open a new screen with one or more images related to the pathology, most of them being photographs of the surface of the cornea, but that can also include microscopic images of the cornea.
All images can be expanded for full-screen viewing, or shared with colleagues.
Users can utilize the search function to find a specific condition. This works well and quickly with the help of the autocomplete.
Cornea Atlas app is not just a collection of images. Users can tap on the arrow icon that would open a new page containing a brief description of each pathology, with signs, symptoms, risk factors, and treatment.
This part, however, lacks links pointing to the source(s) used that would also provide comprehensive descriptions of the corneal diseases.
This would significantly enhance the educational value of this app, especially for those with little background in ophthalmology, such as students or interns.
Another thing that would improve the app would be adding more interactive features, such as calculators or algorithms that could help users with diagnosis and treatment of corneal diseases.
Overall, Cornea Atlas is a very good app that isn't just a collection of corneal images, but also an easy-to-understand medical reference of clinical presentations for different corneal and external eye disorders, that would be useful to anyone interested in ophthalmology.
The app is available for free, however not for Android
Benefit: I would recommend this app to anyone interested in ophthalmology