What are the differences between cataracts and vitreous opacities?

Cataracts and vitreous opacities are both common eye diseases, generally occurring in middle-aged and elderly people. As age increases, eye function gradually declines and the retina becomes more susceptible to lesions. There is a certain difference between cataracts and vitreous opacities. Generally, cataracts are caused by decreased vision, while vitreous opacities are diseases caused by the fundus.

Difference between cataract and vitreous opacity

Cataract is a decreased vision caused by clouding of the lens in the eye, while vitreous opacities are also called floaters, which are fundus diseases.

Not only are cataracts and vitreous opacities not the same eye disease, but they are also treated differently. Cataracts can only be treated through surgery, while the treatment of vitreous opacities requires the use of medication, lasers, and surgery depending on the patient's eye condition.

Causes of Cataracts

Various reasons such as aging, heredity, local nutritional disorders, immune and metabolic abnormalities, trauma, poisoning, radiation, etc. can cause lens metabolism disorders, leading to lens protein denaturation and turbidity, resulting in cataracts. The disease can be divided into congenital and acquired:

1. Congenital cataract

Also known as developmental cataract, it usually exists before or after birth and is mostly static. It may be accompanied by genetic diseases. There are two types: endogenous and exogenous. Endogenous ones are related to fetal developmental disorders, and exogenous ones are caused by systemic diseases of the mother or fetus that damage the lens. Congenital cataracts are divided into anterior polar cataracts, posterior polar cataracts, circumnuclear cataracts and total cataracts.

2. Acquired cataract

There are 6 types of lens opacities caused by systemic diseases or local eye diseases, abnormal nutritional metabolism, poisoning, degeneration and trauma after birth: ① Senile cataract, the most common, also called age-related cataract, more common in people over 40 years old, and increase with age. It is related to multiple factors, such as degenerative changes caused by slow metabolism in the elderly. Some people also believe that it is related to long-term sunlight exposure, endocrine disorders, metabolic disorders and other factors. According to the location of the initial opacity, it can be divided into two categories: nuclear and cortical. ② Concurrent cataract (complication of other eye diseases). ③Traumatic cataract. ④Metabolic cataract. ⑤Radiation cataract. ⑥Drug and toxic cataracts.

Clinical manifestations

It can be unilateral or bilateral, and the disease may occur in one eye or the other. There is a progressive deterioration of vision. Due to the opacity of the lens cortex, the refractive power of different parts of the lens is different. There may be a sense of glare, or monocular diplopia, and increased myopia. Clinically, senile cataracts are divided into three types: cortical, nuclear, and subcapsular.

1. Cortical cataract

The main feature is grayish white turbidity in the lens cortex, and its development process can be divided into four stages: initial stage, immature stage, mature stage, and overmature stage.

2. Nuclear cataract

Lens opacity begins to increase in density from the center of the lens, where the embryonic nucleus is located, gradually worsens and slowly expands to the periphery. It is light yellow in the early stages. As the opacity worsens, the color gradually deepens to dark yellow, dark brown, the density of the nucleus increases, and the refractive index increases. Patients often complain that their presbyopia has decreased or their myopia has increased. In the early stages, the peripheral cortex is still transparent. Therefore, the pupil dilates and vision improves in the dark, but the pupil constricts and vision deteriorates in strong light. Therefore, surgery is generally performed without waiting for the cortex to become completely opaque.

3. Posterior subcapsular cataract

The opacity is located in the subcapsular cortex of the lens. If it is located in the visual axis area, it will affect vision at an early stage.