Senile cataract
What is a senile cataract?
The human eye functions in a way similar to the way a camera does. The natural lens of the eye is a convex-shaped structure that is 9 mm in diameter and 4 mm thick. It collects light rays and brings an image into focus. However these functions decline with age and, consequently, seeing at close range becomes difficult. This situation is called presbyopia (farsightedness due to old age). The lens is a transparent tissue; its purpose is to collect light, focus it onto the retina which is located at the back of the eye, and produce images of outside objects. When the lens is clouded, light rays are scattered before reaching the retina; it weakens the ability to produce images, resulting in blurred vision. Clouding of the lens is called a cataract.
What symptoms are present when one gets a senile cataract?
(1) Blurring of vision
When the cloudiness is near the center of the lens, your vision becomes
blurred. If the cloudiness develops further, you will have difficulty seeing
things (Figure 1).
(2) Glaring
Because light reflects on the cloudy part of the lens, it makes the sunlight
or backlight too bright, or causes worsened vision. When the clouding is
near the center of the lens, glaring becomes more severe (Figure 2).
(3) Poor vision in the dark
The lens gets yellowish due to aging. In addition to clouding, it makes it
hard to see things in the dark (Figure 3).
(4) Temporarily improved vision
When a nuclear cataract develops, the refractive index will increase and
your eyesight will seem to improve. You can see things without
eyeglasses; however, you will have difficulty seeing things far away.
(5) Double vision
You may have double or triple vision depending on the degree of
cloudiness.
(6) No pain, nor bloodshot eyes
You will have neither pain nor bloodshot eyes because there are no nerves
and blood vessels in the lens. However, on rare occasions, advanced
cloudiness may cause glaucoma; it may result in acute pain and red eyes.
Glaucoma
What is glaucoma?
Glaucoma is a disease that leads to a narrowed visual field due to damage of the optic nerve. High inner eye pressure is considered to be one of the causes.
Development of damage to the visual field
（The figures below are images when one sees a thing with the right eye）
In actual cases, one is unaware of the development because one sees things with both eyes, or by moving the eye.
Symptoms and Treatment Retinal Detachment
What is retinal detachment?
The neurosensory retina may separate from the retinal pigment epithelial cells because adhesion between these two layers is weak. In consequence, the retinal pigment epithelium layer may float in the vitreous body. This condition is called retinal detachment. The most common type of this disorder is rhegmatogenous retinal detachment which usually accompanies a break or a tear in the retina.
Symptoms of retinal detachment
If you have one or more of the symptoms described below, visit an eye care specialist
and have a medical check-up.
●Muscae volitantes, photopsia, visual field defect, poor vision
