Glaucoma is one of those eye diseases that gradually causes vision loss and ultimate blindness. It causes optic nerve damage, which cannot be restored when blindness has occurred. Symptoms progress so slowly that one may not know until they emerge.
Unless one undergoes the required diagnostic tests and treatments, it would be very difficult for one to manage/treat this condition. Since symptoms come on gradually, it is difficult to ascertain whether there exist any acute ones in this regard.
Glaucoma: Its Causes And Types
As mentioned above, glaucoma presents as a grave eye condition due to its tremendous likelihood of causing blindness in the long run. It happens due to the damage caused to the optic nerves of the eye. As these nerves deteriorate, blind spots appear in the way of one’s vision, gradually leading to vision loss and blindness. Intraocular pressure in the eye is well attributed to this condition.
Depending on the intensity at which pressure builds in the eyes, glaucoma presents as either open- or closed-angle glaucoma.
- Open-Angle Glaucoma: There is a slow and small increase in eye pressure.
- Closed-Angle Glaucoma: Contrary to open-angle glaucoma, pressure buildup is sudden and in high amounts.
One can, therefore, be rest assured that glaucoma is open-angled in most cases, further indicating that vision loss occurs slowly. Because symptoms develop slowly, these cannot render glaucoma as acute. Hence, one can conveniently mention that there does not exist any.
It can also be stated that once symptoms emerge, these tend to be of sudden onset and present as severe unilateral eye pain. Acute angle-closure glaucoma as this is otherwise called, is also associated with vision blur and seeing rainbow-colored halos around bright lights. One can also get nauseated, vomiting being the extreme case.
Anatomy And Pathophysiology Of Acute Angle-Closure Glaucoma
When explaining the mechanism behind Acute Angle-Closure Glaucoma, one should understand what the term ‘angle’ signifies here. Anatomically, it suggests the one lying between the iris and the cornea in the anterior chamber.
The structural obstruction faced by the intraocular fluid, i.e., the aqueous humor is what leads to acute angle-closure glaucoma. On a physical exam, there can be seen a haziness or cloudiness of the cornea, marked by a fixed midpoint pupil. Marked conjunctival injection may also be present.
The etiology of intraocular pressure (IOP) involves a blockage to the outflow of the aqueous humor. The aqueous humor is a fluid that helps moisturize the front part of the eye by flowing from the posterior to the anterior chamber.
The IOP developing within the fluid tends to damage the optic nerve in the long term. A glaucoma patient, therefore, needs to keep this pressure within normal range. Per clinical guidelines, normal IOP should stay between 10-22 mmHg (millimeters of Mercury).
There exist several factors to explain the obstruction of the aqueous humor, leading to IOP. Among these, structural obstruction in the eye’s anterior chamber happens to be most common. The shallower angle formed in the anterior chamber causes a larger area of the iris and the lens to come in contact with each other.
Factors Causing Elevated IOP
The three most important factors triggering elevated IOP include:
- The rate at which aqueous humor is produced by the ciliary body
- Resistant to the outflow of the aqueous humor through the trabecular meshwork and the Schlemm’s canal.
- Episcleral Venous Pressure
Being produced by the ciliary body, the aqueous humor flows out through the trabecular meshwork and the Schlemm’s Canal.
Risk Factors Of Glaucoma
Among the various risks linked to glaucoma, a majority of them have included the following:
- Age: One normally develops glaucoma by age 60, wherein the lens size increases. However, certain predisposing factors may cause one to develop glaucoma at an earlier age, say 40-50.
- Gender: The ratio of women to men developing glaucoma is 4:1, indicating that the former is at higher risk.
- Race: It is the Southeast Asians, the Chinese, and Eskimos who are more likely to develop acute angle-closure glaucoma.
- Family History: Out of the many inherited disease profiles, one can easily pass on one’s ocular anatomical features to one’s offspring.
Diagnosis And Treatment For Glaucoma
Glaucoma can be effectively diagnosed through a comprehensive dilated eye exam and visual field testing. Also, ophthalmoscopy, tonometry, perimetry, and imaging techniques can be utilized to judge the presence and extent of glaucoma. Though it is not completely curable, the IOP causing the condition can be effectively controlled with eye drops.
Similarly, laser therapy and glaucoma surgery can be considered if medications alone are not effective in lowering the IOP. The primary aim of these treatments should be to reduce intraocular pressure and should be rendered in view of this purpose.
Given that advanced glaucoma significantly exposes an individual to lifetime blindness, timely diagnosis and treatment will drastically reduce this risk. However, since symptoms progress slowly, it would be difficult to determine when glaucoma strikes. Unfortunately, it is only when symptoms come to the forefront that people realize the seriousness of this eye condition.
Due to this peculiarity of glaucoma, i.e., the late presentation of symptoms, it is rather impossible to remark them as acute. Nevertheless, when they occur, they appear as severe unilateral eye pain, blurred vision, and rainbow halo around bright light as mentioned earlier.
These presentations are what classify glaucoma as acute angle-closure glaucoma. This is due to the IOP, causing outflow obstruction of the aqueous humor, damaging the optic nerves gradually. Of note, the factors causing IOP have been listed in a previous section.