There are hundreds of different eye diseases, with some of the most common major eye diseases including age-related macular degeneration (AMD) - an age-related eye disease that can blur central vision - glaucoma - a condition where the optic nerve becomes damaged - and diabetic retinopathy (DR) - a complication of diabetes in which high blood sugar levels damage the retina.\n\n\n\nAlthough some eye diseases are treatable, others are very much lacking in effective treatment options, and no cures are available that can reverse the effects of certain conditions.\n\n\n\nThere are many ophthalmology biotech companies that are focusing on developing better treatment options for various different eye diseases. In fact, in 2021, ophthalmology-focused startups in Europe had a record year for venture capital funding, with success carrying on into 2022, and it seems big pharma has set its sights on ophthalmology opportunities in recent times. \n\n\n\nHere, in alphabetical order, we have listed five of the top ophthalmology companies focused on creating therapies for a range of eye diseases.\n\n\n\n\n\nAzura Ophthalmics\n\n\n\nAzura Ophthalmics aims to create treatments for ophthalmic conditions by harnessing the properties of keratolytics, which are compounds that are normally used to break apart the disulfide bonds that bind keratin together into aggregates to treat skin conditions such as acne, seborrheic dermatitis and psoriasis. \n\n\n\nHowever, because abnormal keratin - a protein that helps to form hair, nails and the skin’s outer layer - production, deposition, and aggregation are pathognomonic to many ocular surface diseases, Azura is developing a portfolio of keratolytic agents for the treatment of lid margin diseases and associated conditions. \n\n\n\nThe ophthalmology company has a pipeline of new chemical entities, and its lead candidate is AZR-MD-001, for the treatment of meibomian gland dysfunction (MGD). MGD is a common condition that occurs when the meibomian glands do not produce enough oil, called meibum, or the oil is of poor quality, and it is a common underlying cause of dry eye syndrome and blepharitis. \n\n\n\nLast year, Azura announced positive results from its phase 2b trial of AZR-MD-001 for MGD, with the trial meeting its co-primary endpoints of improvements in meibomian glands yielding liquid secretion and Ocular Surface Disease Index score compared with vehicle.\n\n\n\nBreye Therapeutics\n\n\n\nWith the aim of addressing the unmet medical need to develop more effective and less burdensome therapies for patients and caregivers, Breye Therapeutics is developing novel, orally administered ophthalmology drugs for patients with vision loss. Its focus is on DR and AMD. \n\n\n\nTo treat these conditions, the ophthalmology company is developing danegaptide - a small molecule drug - as an oral therapy that targets retinal pathologies, in order to reverse the underlying cause of retinal vascular diseases. Danegaptide has a mode of action that protects from cell-cell uncoupling, retinal capillary breakdown, and vascular leakage caused by high glucose-stressed conditions. \n\n\n\nLast year, Breye Therapeutics closed a seed financing round of €4 million ($4.1 million), which was led by Novo Holdings and Sounds Bioventures. \n\n\n\nEyeBio\n\n\n\nOphthalmology company EyeBio raised $65 million in series A financing last year to develop a new generation of eye disease therapies that will protect, restore and improve vision. \n\n\n\nEyeBio recently announced details on Restoret, which is the company’s lead asset in its multi-specific agonist antibody pipeline. Restoret is a tri-specific agonist antibody targeting the Wnt pathway, and is designed to address unmet medical need in patients with back-of-the-eye diseases. Wnt signaling in the retina plays a central role in the maintenance of vascular integrity, with defects in Wnt signaling causing retinal vascular leakage.\n\n\n\nRestoret is delivered by intravitreal injection to specifically treat retinal diseases that are characterized by leakage, including neovascular age-related macular degeneration (NVAMD), diabetic macular edema (DME), and familial exudative vitreal retinopathy (FEVR). \n\n\n\nEyeBio plans to file for clinical trial authorizations to enable a global phase 1b/2 clinical trial of Restoret later this year. \n\n\n\nOxurion\n\n\n\nPreviously known as ThromboGenics, ophthalmology company Oxurion’s focus is around developing treatments for diabetic eye diseases. Its lead candidate is called THR-149, for the treatment of DME. \n\n\n\nTHR-149 was licensed from Bicycle Therapeutics and is a bicyclic peptide that selectively inhibits human plasma kallikrein (PKal) - a mediator of vascular leakage, inflammation, micro-hemorrhages and neurodegeneration. By inhibiting the kallikrein-kinin system (KKS), it prevents the induction of retinal vascular permeability and inflammation.\n\n\n\nOxurion has just announced that it has completed its enrollment target of 108 patients in a randomized phase 2b trial called KALAHARI, which aims to evaluate THR-149 for the treatment of DME against the current standard of care, aflibercept. \n\n\n\nIf the trial produces a positive outcome, it could mean that THR-149 could provide an alternative for patients with DME who respond suboptimally to current anti-VEGF therapies.\n\n\n\nSpliceBio\n\n\n\nLast year, Spanish company SpliceBio was able to raise €50 million ($52.7 million) in oversubscribed series A financing, which will allow the company to concentrate on taking its lead program for Stargardt disease into phase 1 clinical trials.\n\n\n\nStargardt disease is a rare genetic eye disease that happens when fatty material builds up on the macula - which is the small central part of the retina - and causes vision loss, mainly in children and young adults. The disease itself is caused by an alteration in a single gene called the ABCA4 gene. \n\n\n\nHowever, the ABCA4 gene is too large at 6.8kb for single adeno-associated virus (AAV) vectors to package enough genetic material to treat it, as AAV vectors can only package 4.7kb of genetic material.\n\n\n\nIn an attempt to overcome the capacity limitations presented by AAV vectors, SpliceBio is working on harnessing the potential of inteins, which are a family of proteins that carry out a process called protein splicing, sticking peptides together to form new proteins. By taking advantage of this process, company co-founders Miquel Vila-Perelló and Silvia Frutos were able to develop engineered split inteins for therapeutic use. \n\n\n\nThe biotech company now aims to find treatments for Stargardt disease and other indications in ophthalmology - as well as other therapeutic areas - through its Protein Splicing platform.