The eye is a complex organ made of intricate structures that are arranged in perfect order to enable sight into our lives. Generally, it comprises three layers, the inner retina, the middle choroid and the outermost sclera which is the white part of the eye. The light that enters through our pupils gets focused with the help of the aqueous and vitreous humour. The focused light lands on the retina, gets processed into electric signals and brought to the brain to get interpreted. Defects in any of these pathways may result in change or loss of vision.
Diseases of the eye are very complex, and it could involve the sclera, the lens, the pupil, among others. Today we are going to explore a retinal disease called retinitis pigmentosa (RP). We shall talk about retinitis pigmentosa symptoms and whether or not it can be cured.
Retinitis pigmentosa is a degenerative disease of the retina. It is a chronic disease leading to a gradual loss of vision. It can happen due to a group of rare genetic disorders that targets the destruction and breakdown of the light receptors in the retina
There are two types of light receptors, they are the cones and rods. The cones are responsible for colour vision, and they are located more densely in the middle of the retina enabling central vision and high spatial acuity. The rods, on the other hand, are responsible for vision at low light with no capacity to differentiate colours. They are located in the periphery of the retina. These features help in seeing objects in the dark and peripheral vision.
Retinitis pigmentosa affects the rods more than the cones. Therefore, the first symptom that people with RP will experience is worsening night blindness. What this means is, a person will have difficulty seeing things clearly in dimly-lit rooms, frequent bumping into furniture and difficulty adjusting vision when entering from a bright place to a darker room, the cinema for example. Later, there will be a loss of peripheral vision. There will be complaints such as tunnel vision and inability to see the surroundings clearly. It is important to note that visual acuity is not affected in this condition unless superimposed with other defects in the eye. Occasionally there will also be photopsia, which is seeing flashes of light.
Progress of the disease is variable, with some developing into blindness while some retain 20/40 vision over the years. Retinitis pigmentosa is frequently associated with certain diseases:
Usher Syndrome
RP with concurrent hearing loss. Hearing loss usually precedes loss of sight.
Leber’s Congenital Amaurosis (LCA)
RP identified through significant loss of vision early at birth associated with deep-set eyes, roving eye movements and light sensitivity.
Cone-Rod Disease
Commonly occurring in early childhood, with disease initiating with impaired visual acuity and light sensitivity, followed by disruption in colour vision, the appearance of blind spots in central vision, and loss of peripheral vision.
Bardet-Biedl Syndrome
RP associated with obesity, kidney failure, extra toes or fingers, and deficiency in sex hormones.
CMV Retinitis
Retinitis as sequelae of herpes virus infection. Typically seen in patients with impaired immune system.
There is still no cure for RP currently, but there are medications that can slow the progress of disease and surgical advancements that show some varying improvements. Treatment options include:
Acetazolamide
Reduce associated swelling inside the eye (macular edema) and improve vision.
Vitamin A palmitate
In high doses, it may retard the progress of RP. But this should be under the supervision closely monitored by your doctor for fear of toxicity.
Sunglasses
This simple method may make your eyes less sensitive to light and protect them from the sun’s damaging rays that could worsen RP.
Retinal implant
In late-stage RP, this option may restore partial sight. By incorporating a bionic eye or retinal prosthesis a person may be able to locate people and objects in a room, the lights and windows, and even read letters within 9 inches.
Stem cell therapy
Still, in need of extensive research, stem cell placed within the diseased photoreceptors theoretically will heal the surrounding cells and even develop into the rods and cones themselves.
Retinitis pigmentosa is a rare disease and often associated with a syndrome. If you are having concerns over your vision or the people close to you, it is best to consult your doctor and get the appropriate checkup and treated accordingly.
