Ophthalmology (Eye Health & Eye Diseases)


Retinal Diseases

Retina is a net-like layer lining back wall of the eyeball like a wall paper and consisting of vision cells; it is the innermost layer of the eye. It has vision cells on it. 95% of the act of vision takes place in the yellow spot in the center of the retina.

Any disease occurring in the retina directly threatens our sense of sight. The most common symptoms seen in retinal diseases are as follows:

  • Sudden or slow vision loss
  • Broken or curved vision
  • Flashes of light
  • Dark bodies floating in front of your eyes
  • Obstruction of vision
  • Transient and short-term loss of vision

Retinal diseases can be exemplified by the following diseases:

  • Bleeding due to diabetes and hypertension
  • Retinal vein occlusions
  • Retinal detachments / tears
  • Yellow spot disease
  • Diabetics
  • Congenital retinal diseases
  • Retinal edema
  • Foreign bodies which have entered the eye
  • Macular holes
  • Vitreoretinal surface disorders
  • Retinal tumors

Retinal Hemorrhage

Vitreous is the transparent liquid with a gel structure filling inside the eyeball. Bleeding into vitreous may develop as a result of diseases including diabetes, hypertension, trauma, etc. Blood filling inside of vitreous impairs the patient's sight and prevents the physician from diagnosing the cause in the retina leading to intraocular bleeding.

Patients with intravitreal hemorrhage typically would suffer sudden loss of vision.

In the case of mild intravitreal hemorrhage, patients refer to objects floating in the air or an image resembling soot pouring.

Following visual acuity testing, an attempt is made to examine posterior segment with the help of a lens; where this is challenging due to bleeding, ultrasound is utilized.

Causes of retinal hemorrhage :

  • Diabetes
  • High blood pressure
  • Retinal Detachment: It develops because of tears or holes in the retina. It is most commonly seen in patients with high myopia. It may occur at any age but it is more common in middle ages and above.

Treatment

Unless vitreus bleeding is caused by trauma or retinal detachment, it is allowed to stand without treatment for some time due to the possibility of self-absorption. During this period, it is recommended that the patient drinks plenty of water and lies upright in bed with a pillow placed behind his neck. However, where bleeding isn't reduced, surgery is required to treat vitreous hemorrhage. This procedure ensures removal of vitreous gel and is called pars plana vitrectomy.

Retinal Detachment and Tears

Retinal tears develop as a result of the thinning of the retinal layer associated with the growth of the eyeball most commonly in people with high myopia. However, retinal tears may develop in healthy eyes following a trauma or lifting heavy loads. Retinal thinning may also develop after retinal infections or some degenerative retinal diseases, and retinal tears may occur from these areas thereafter.

Retina is in contact with vitreous gel covering the insdei of the eye. In a healthy eye, vitreous is homogenous, has a gel-like consistency and supports the retina. The consistency of this gel structure changes, liquefies as a result of aging of vitreous over time. Intraocular gel that has liquefied loses its ability to support retina and detaches from its underlying retinal layer. This detachment is called posterior vitreous detachment. This detached vitreous gel fluctuates inside the eye by eye movements and this is referred to by patients as floating black spots or veils.

While intraocular gel detaches from the retina, it causes tractions. As a result of these tractions, mechanical impulse created in the retina is perceived as flashes of light or flashes of lightning. These tractions may cause tears in the retina that has thinned. If torn retinal layer passes over a vessel, bleeding into the eye may occur. Liquefied intraocular gel enters into the tear in the retina and causes detachment of retinal nerve layer from the underlying layer, leading to retinal detachment. Visual function of the area of retina that has detached from the underlying tissue is reduced.

Retinal tears in which retinal detachment hasn't developed are surrounded by argon laser and seeping of liquid is prevented.

Retinal detachment is a disorder that may progress up to blindness, a medical emergency, and can only be treated by surgery. In this case, the vitreous gel is removed and inside of the eye is filled with special buffering agents(a gas bubble or silicon oil).

Retinal Vein Occlusions

Retinal vein occlusions are in second place among retinal vascular diseases after diabetes. The main problem is damage in the walls of retinal vessels. It is frequently seen between the ages of 50-60 years. Patients usually complain about sudden, painless loss of vision.

It manifests itself by sudden, painless loss of vision which is not transient. Depending on the vein which has been affected by the disease, either a minimal loss in vision may occur or very serious loss of vision may be encountered.

Risk factors involved in development of retinal vascular occlusion are as follows:

  • Aging
  • Smoking
  • Hypertension and diabetes
  • Glaucoma (increased intraocular pressure )

If a section of retinal vein has been occluded and there is accumulation of fluid in visionary center, laser treatment is applied and cortisone treatment is applied into the eye.

Macular Degeneration

It is a condition in which the macula in retina is impaired and vision is reduced because of aging.

Patient sees straight lines as broken. He cannot see the point he is looking at but can see its surroundings. Near vision and reading are affected the most.

It is certainly more common in smokers. It mostly develops above the age of 70 but the risk starts over the age of 55.

There are two types: dry type and wet type.

  • In dry type, capillaries are intact and there is no bleeding. Vision is reduced but it doesn't lead to blindness.
  • In wet type, capillaries are susceptible and there is bleeding. It carries risk of blindness. Argon laser, photodynamic therapy, and intraocular injections are used to treat the wet type.

Treatment of Macular Degeneration

Treatment of dry type is applied by oral support medications. Argon laser, photodynamic therapy, and intraocular injections are used to treat the wet type.

In photodynamic therapy, capillaries causing bleeding in the retina are stained by a special medication injected into the arm of the patient, and diseased area is destroyed by laser applied to the region stained.

In the case of intraocular infections, medications called anti-VEGF are used. Injection procedure is easy and painless for the patient. Intraocular injections are made for 3 times with one month in between.

It is also possible to significantly help patients with reduced vision with special glasses called LVA. Most of the patients gain vision with these glasses to the extent that they can comfortably read a newspaper.

Patients with macular degeneration are required to be examined every 4 months.

Diabetic Retinopathy

It is the most common cause of diabetes-induced blindness. Diabetes especially affect and impair nervous layer(retina) and capillaries in this layer, leading to loss of vision. Damage to retina induced by diabetes is called diabetic retinopathy.