The early stages of pellucid marginal degeneration may also be managed with soft contact lenses. Success has been shown with the use of rigid gas permeable contact lenses combined with over-refraction. Patients wearing contacts dont report increased problems with glare and contrast sensitivity, but it is not clear if this is due to the corneal disease, or the contact lenses themselves.

New studies found that the use of Scleral contact lens, a type of rigid gas permeable (RGP) lens, may be a good option for most patients with PMD. Most of these lenses are in the range of 15.5mm to 18.0mm in diameter. Regardless of the lens size, it is thought that the larger the RGP lens will in most cases be more comfortable then standard rigid corneal lenses, and at times more comfortable than soft lenses, regardless of the fact that it is a rigid lens. The highlight to the scleral design and the correction of eye disorders such as pellucid marginal degeneration is that vision with these types of lenses is exceptional when fit correctly.

Most patients can be treated non-surgically with eyeglasses, or contact lenses.

Spectacles or RGP contact lenses can be used to manage the astigmatism. when the condition worsens, surgical correction may be required.

Laser treatment of drusen has been studied. While it is possible to eliminate drusen with this treatment strategy, it has been shown that this fails to reduce the risk of developing the choroidal neovascularisation which causes the blindness associated with age-related macular degeneration.

Several other corneal ectatic disorders also cause thinning of the cornea:

- Keratoglobus is a very rare condition that causes corneal thinning primarily at the margins, resulting in a spherical, slightly enlarged eye. It may be genetically related to keratoconus.

- Pellucid marginal degeneration causes thinning of a narrow (1–2 mm) band of the cornea, usually along the inferior corneal margin. It causes irregular astigmatism that, in the early stages of the disease can be corrected by spectacles. Differential diagnosis may be made by slit-lamp examination.

- Posterior keratoconus, a distinct disorder despite its similar name, is a rare abnormality, usually congenital, which causes a nonprogressive thinning of the inner surface of the cornea, while the curvature of the anterior surface remains normal. Usually only a single eye is affected.

- Post-LASIK ectasia is a complication of LASIK eye surgery.

Barrage laser is at times done prophylactically around a hole or tear associated with lattice degeneration in an eye at risk of developing a retinal detachment. It is not known if surgical interventions such as laser photocoagulation or cryotherapy is effective in preventing retinal detachment in patients with lattice degeneration or "asymptomatic" retinal detachment. Laser photocoagulation has been shown to reduce risks of retinal detachment in "symptomatic" lattice degeneration. There are documented cases wherein retina detached from areas which were otherwise healthy despite being treated previously with laser.

No complications are encountered in most patients with lattice degeneration, although in young myopes, retinal detachment can occur. There are documented cases with macula-off retinal detachment in patients with asymptomatic lattice degeneration. Partial or complete vision loss almost always occurs in such cases. Currently there is no prevention or cure for lattice degeneration.

In early stages of keratoconus, glasses or soft contact lenses can suffice to correct for the mild astigmatism. As the condition progresses, these may no longer provide the person with a satisfactory degree of visual acuity, and most practitioners will move to manage the condition with rigid contact lenses, known as rigid, gas-permeable, (RGP) lenses. RGP lenses provide a good level of visual correction, but do not arrest progression of the condition.

In people with keratoconus, rigid contact lenses improve vision by means of tear fluid filling the gap between the irregular corneal surface and the smooth regular inner surface of the lens, thereby creating the effect of a smoother cornea. Many specialized types of contact lenses have been developed for keratoconus, and affected people may seek out both doctors specialized in conditions of the cornea, and contact lens fitters who have experience managing people with keratoconus. The irregular cone presents a challenge and the fitter will endeavor to produce a lens with the optimal contact, stability and steepness. Some trial-and-error fitting may prove necessary.

Treatment options include contact lenses, intrastromal corneal ring segments, corneal collagen cross-linking, or corneal transplant.

When cross-linking is performed only after the cornea becomes distorted, vision remains blurry even though the disease is stabilised. As a result, combining corneal collagen cross-linking with LASIK ('LASIK Xtra') aims to strengthen the cornea at the point of surgery and may be useful in cases where a very thin cornea is expected after the LASIK procedure. This would include cases of high spectacle power and people with thin corneas before surgery. Definitive evidence that the procedure can reduce the risk of corneal ectasia will only become available a number of years later as corneal ectasia, if it happens, usually occurs in the late post-operative period. Some study show that combining LASIK with cross-linking adds refractive stability to hyperopic treatments and may also do the same for very high myopic treatments.

In 2016, the FDA approved the KXL system and two photoenhancers for the treatment of corneal ectasia following refractive surgery.

As it is associated with excessive sun or wind exposure, wearing protective sunglasses with side shields and/or wide brimmed hats and using artificial tears throughout the day may help prevent their formation or stop further growth. Surfers and other water-sport athletes should wear eye protection that blocks 100% of the UV rays from the water, as is often used by snow-sport athletes. Many of those who are at greatest risk of pterygium from work or play sun exposure do not understand the importance of protection.

Usually being asymptomatic, drusen are typically found during routine eye exams where the pupils have been dilated.

While choroideremia is an ideal candidate for gene therapy there are other potential therapies that could restore vision after it has been lost later in life. Foremost of these is stem cell therapy. A clinical trial published in 2014 found that a subretinal injection of human embryonic stem cells in patients with age-related macular degeneration and Stargardt disease was safe and improved vision in most patients. Out of 18 patients, vision improved in 10, improved or remained the same in 7, and decreased in 1 patient, while no improvement was seen in the untreated eyes. The study found "no evidence of adverse proliferation, rejection, or serious ocular or systemic safety issues related to the transplanted tissue." A 2015 study used CRISPR/Cas9 to repair mutations in patient-derived induced pluripotent stem cells that cause X-linked retinitis pigmentosa. This study suggests that a patient's own repaired cells could be used for therapy, reducing the risk of immune rejection and ethical issues that come with the use of embryonic stem cells.

Treatment options include contact lenses and intrastromal corneal ring segments for correcting refractive errors caused by irregular corneal surface, corneal collagen cross-linking to strengthen a weak and ectatic cornea, or corneal transplant for advanced cases.

A practical application of AMD-associated genetic markers is in the prediction of progression of AMD from early stages of the disease to neovascularization.

Cell based therapies using bone marrow stem cells as well as retinal pigment epithelial transplantation are being studied. A number of trials have occurred in humans with encouraging results.

Gene therapy is currently not a treatment option, however human clinical trials for both choroideremia and Leber's congenital amaurosis (LCA) have produced somewhat promising results.

Clinical trials of gene therapy for patients with LCA began in 2008 at three different sites. In general, these studies found the therapy to be safe, somewhat effective, and promising as a future treatment for similar retinal diseases.

In 2011, the first gene therapy treatment for choroideremia was administered. The surgery was performed by Robert MacLaren, Professor of Ophthalmology at the University of Oxford and leader of the Clinical Ophthalmology Research Group at the Nuffield Laboratory of Ophthalmology (NLO).

In the study, 2 doses of the AAV.REP1 vector were injected subretinally in 12 patients with choroideremia.

There study had 2 objectives:

- to assess the safety and tolerability of the AAV.REP1 vector

- to observe the therapeutic benefit, or slowing of the retinal degeneration, of the gene therapy during the study and at a 24-month post-treatment time point

Despite retinal detachment caused by the injection, the study observed initial improved rod and cone function, warranting further study.

In 2016, researchers were optimistic that the positive results of 32 choroideremia patients treated over four and a half years with gene therapy in four countries could be long-lasting.

CNV is conventionally treated with intravitreal injections of angiogenesis inhibitors (also known as "anti-VEGF" drugs) to control neovascularization and reduce the area of fluid below the retinal pigment epithelium. Angiogenesis inhibitors include pegaptanib, ranibizumab and bevacizumab (known by a variety of trade names, such as Macugen, Avastin or Lucentis). These inhibitors slow or stop the formation of new blood vessels (angiogenesis), typically by binding to or deactivating the transmission of vascular endothelial growth factor ('VEGF'), a signal protein produced by cells to stimulate formation of new blood vessels. The effectiveness of angiogenesis inhibitors has been shown to significantly improve visual prognosis with CNV, the recurrence rate for these neovascular areas remains high.

CNV may also be treated with photodynamic therapy coupled with a photosensitive drug such as verteporfin (Visudyne). The drug is given intravenously. It is then activated in the eye by a laser light. The drug destroys the new blood vessels, and prevents any new vessels forming by forming thrombi.

Pterygium typically do not require surgery unless it grows to such an extent that it causes visual problems. Some of the symptoms such as irritation can be addressed with artificial tears. Surgery may also be considered for unmanageable symptoms.

The Fuchs spot or sometimes Forster-Fuchs' retinal spot is a degeneration of the macula in case of high myopia. It is named after the two persons who first described it: Ernst Fuchs, who described a pigmented lesion in 1901, and Forster, who described subretinal neovascularisation in 1862. The size of the spots are proportionate to the severity of the pathological myopia.

Before LASIK surgery, people must be examined for possible risk factors such as keratoconus.

Abnormal corneal topography compromises of keratoconus, pellucid marginal degeneration, or forme fruste keratoconus with an I-S value of 1.4 or more is the most significant risk factor. Low age, low residual stromal bed (RSB) thickness, low preoperative corneal thickness, and high myopia are other important risk factors.

Treatments for corneal neovascularization are predominately off-lab with a multitude of complications as a result. The desired results from medical therapy may not always occur, ergo an invasive procedure may be needed to prevent further decrease in corneal avascularity.

For contact lenses related hypoxia, ceasing the use of contact lenses is the first step until corneal neovascularization is addressed by a physician. Modern rigid gas permeable and silicon hydrogel contact lenses have a much higher level of oxygen transmissibility, making them effective alternatives to help prevent corneal neovascularization.

Topical administration of steroids and non-steroid anti-inflammatory drugs are first-line treatment for individuals with CNV. The administration of steroids can increase the risk of infection, glaucoma, cataracts, herpes simplex recurrence. The anti-inflammatory drugs, however, increase the risk of corneal ulceration and melting.

Since VEGF plays an important role in vasculogenesis and pathologic neovascularization associated with eye diseases, a potential treatment for CNV is to inhibit VEGF activity by competing the binding of VEGF with specific neutralizing anti-VEGF antibody. VEGF inhibitors include pegatanib sodium, ranibizumab, and off-label bevacizumab are currently used for treatment of various retinal disease. Anti-VEGF antibodies such as the application of ranibizumab or bevacizumab have has been shown to reduce corneal neovascularization. Both ranibizumab and bevacizumab uses the same mechanism and inhibits all iso-forms of VEGF. The significant reduction in invasion of in-growth blood vessels in terms of neovascular area and vessel caliber suggests that treatment with ranibizumab induces thinning of the blood vessels, however, there's no significant change of the blood vessel's length. Using anti-VEGF antibodies to treat CNV has some limitations such as it is not a cure and may require repeated treatments to maintain positive effects over time. Topical and/or subconjunctival administration of bevaicizumab or ranibizumab have demonstrated short-term safety and efficacy, however long term effects have not been documented. Anti-VEGF therapy is currently an experimental treatment.

If the cornea is inflamed via corneal neovascularization, the suppression of enzymes can block CNV by compromising with corneal structural integrity. Corneal neovascularization can be suppressed with a combination of orally administration of doxycycline and with topical corticosteroid.

Surgical Options

Invasive solutions for corneal neovascularization are reserved when the medical therapies do not provide the desired results.

Invading blood tissues and ablating tissues in the cornea can be obstructed by the use of laser treatments such as Argon and s. Irradiation and/or damages to adjacent tissues caused by the procedure can result in corneal hemorrhage and corneal thinning. Obstruction of the blood vessels can be unsuccessful due to the depth, size, and, high blood flow rate of the vessels. In conjunction, thermal damage from the lasers can trigger inflammatory response which can exaggerate the neovascularization.

An effective treatment is photodynamic therapy, however, this treatment has limited clinical acceptance due to high costs and many potential complications involved that are also related to laser ablation. Complications can include irradiation from previously injected photosensitive dye inducing apoptosis and necrosis of the endothelium and basement membrane.

Diathermy and cautery is a treatment where an electrolysis needle is inserted into the feeder vessels in the limbus. The vessels are obstructed by a coagulating current through the use of unipolar diathermy unit or by thermal cautery.

Corneal ectatic disorders or corneal ectasia are a group of uncommon, noninflammatory, eye disorders characterised by bilateral thinning of the central, paracentral, or peripheral cornea.

- Keratoconus, a progressive, noninflammatory, bilateral, asymmetric disease, characterized by paraxial stromal thinning and weakening that leads to corneal surface distortion.

- Keratoglobus, a rare noninflammatory corneal thinning disorder, characterised by generalised thinning and globular protrusion of the cornea.

- Pellucid marginal degeneration, a bilateral, noninflammatory disorder, characterized by a peripheral band of thinning of the inferior cornea.

- Posterior keratoconus, a rare condition, usually congenital, which causes a nonprogressive thinning of the inner surface of the cornea, while the curvature of the anterior surface remains normal. Usually only a single eye is affected.

- Post-LASIK ectasia, a complication of LASIK eye surgery.

- Terrien's marginal degeneration, a painless, noninflammatory, unilateral or asymmetrically bilateral, slowly progressive thinning of the peripheral corneal stroma.

Terrien marginal degeneration is a noninflammatory, unilateral or asymmetrically bilateral, slowly progressive thinning of the peripheral corneal stroma.

The cause of Terrien marginal degeneration is unknown, its prevalence is roughly equal between males and females, and it usually occurs in the second or third decade of life.

Reduction of neovascularization has been achieved in rats by the topical instillation of commercially available triamcinolone and doxycycline.

Some evidence exists to suggest that the Angiotensin II receptor blocker drug telmisartan will prevent corneal neovascularization.

Recent treatment developments include topical application of bevacizumab, an anti-VEGF.

First signs of a Fuchs spot are distorted sight of straight lines near the fovea, which some days later turn to the typical well-circumscribed patches after absorption of haemorrhage, and a pigmented scar remains. As in macular degeneration, central sight is affected. Atrophy leads to the loss of two or more lines of the Snellen chart.