1. Progressive: It is thick, meaty, and vascular, which gradually spreads to the centre of the cornea.
2. Atrophic: It is thin, poorly vascularised, and stagnant.

The factors that must be taken into consideration while evaluating a pterygium: 

1. Location of the pterygium
2. Size of pterygium.
3. The extent of the pterygium spread to the corneal region

Disease Progression of Pterygium

A pterygium does not always lead to vision impairment. But when it progresses to an advanced form, it can cause significant distortion in vision. The stages of pterygium are as follows:

1. Stage 0: In this stage, the lesion is posterior to the limbus (border of the cornea in contact with the sclera). This stage is called Pinguecula, a yellow patch or bump on the conjunctiva. Fat, protein, or calcium deposition occurs on the tissue. 

2. Stage 1: The lesion involves the limbus in this stage, and minimal papillary response is seen. 

3. Stage 2: In this stage, the lesion appears just on the limbus, and minimal elevation is observed on the conjunctiva.

4. Stage 3: In this stage, the head of the pterygium covers the area between the limbus and the papillary margin. The lesion is up to 1 mm.

5. Stage 4: This is an extreme case where the pterygium is central to the papillary margin and extends more than 1 mm. As this stage involves areas of vision, it can lead to limitations in eye movement. 

1. Redness 
2. Irritation
3. Blurred vision
4. Itchiness
5. Burning sensation
6. Gritty eyes

The precise cause of pterygium is unknown. One explanation for these growths is excessive ultraviolet (UV) light exposure. People who live in warm regions and spend a lot of time outdoors in windy or sunny conditions are more likely to experience it. This disorder is more likely to affect those whose eyes are regularly exposed to particular elements. Below are some of the causes of pterygium that develops in a person:

1. Dry eyes
2. Excessive exposure to ultraviolet light
3. Irritants like wind, dust, smoke, and pollen

Pterygium is associated with several risk factors, including sun exposure, geographic latitude, ageing, nationality, and skin tone. The risk factors of pterygium fall into three categories:

1. Demographic: Older age, males, and people with outdoor occupations
2. Environmental: Exposure to sunlight
3. Lifestyle: Cigarette smoking, alcohol consumption

Pterygium might not always be completely avoidable. The chance of a pterygium developing can still be decreased, though. The following measures can be adopted to prevent a surfer’s eye formation or reduce the risk of a pterygium recurrence.

1. Use sunglasses to block ultraviolet rays.
2. Wear a hat whenever out in the sun.
3. Avoid exposas much as possible exposure to environmental irritants such as smoke, dust, wind, and chemical pollutants
4. Use appropriate eye safety equipment in the workplace.

The diagnosis of pterygium is made without the use of special tests. The ophthalmologist will use a slit lamp to perform a physical examination and diagnose the condition. A slit lamp consists of a microscope and a bright light that helps the doctor examine the eye. If the doctor needs to perform some additional tests, they may include:

1. Photo Documentation: This test involves taking photographs of the patient’s eyes to track pterygium growth.
2. Avoid exposas much as possible exposure to environmental irritants such as smoke, dust, wind, and chemical pollutants.
3. Use appropriate eye safety equipment in the workplace
4. Visual Acuity Test: It consists of reading letters on a standardised eye chart
5. Corneal Topography: This is a computer-assisted diagnostic test to measure the curvature changes in the cornea

How to prepare for the doctor's consultation?

1. List down symptoms including any that may seem unrelated to the condition.

2. List down the relevant events that may be related to the condition.

3. The patient must tell the doctor the list of medications and supplements that he takes.

4. The following questions should be asked the doctor:

   1. What treatment is best suitable for me?

   2. How can I stay comfortable in this condition?

   3. Do you think I have any other conditions?

   4. Do I need to see a specialist for my condition?

   5. Why is surgery needed?

If the patient has no significant troublesome symptoms of the pterygium, it may go away on its own. But, if the symptoms persist for a more extended period or more than a week, then the ophthalmologist may suggest one of the following treatment methods for pterygium.

Pterygium treatment without surgery

1. For symptoms of dry eye, lubricants in the form of eye drops

2. Spectacles for astigmatism that isn't very severe.

3. Steroid eye drops for Pterygium that is inflamed.

Pterygium treatment with surgery

Pterygium surgery is advised in the following circumstances:

1. The possibility of a progressive pterygium

2. Periodic flare-ups of inflammation

3. Double vision

Additional steps must be taken to prevent pterygium recurrence after simple surgical excision is done if needed. These include:

1. Conjunctival Autograft: This procedure involves taking a small piece of conjunctiva from either the same or the opposite eye and transplanting it to the location where the pterygium was removed and left a defect. A conjunctival transplant provides normal stem cells to encourage normal conjunctival development.

2. Amniotic Membrane Grafting: The amniotic membrane, the placenta's innermost layer, which surrounds the foetus, is taken from healthy, full-term caesarian babies. The membrane is then stretched over the region where the pterygium was removed after being trimmed to the correct size. The amniotic membrane is fixed in place using a specific adhesive or sutures. 

3. Mitomycin C: This substance prevents growth at the conjunctival level, aiding in avoiding recurrences. It is either applied to the bed of the sclera after the pterygium is removed or given as eye drops following the procedure.

For minor pterygium cases, eye drops and ointment can usually treat inflammation. Only in the more severe cases does treatment involve surgical removal of pterygium. However, if left untreated, the growth can extend across the pupil, leading to:

1. Scarring on the cornea
2. Daily discomfort
3. Vision loss
4. Cosmetic concerns
5.  

When to see a doctor?

The patient can consult the doctor if he/she experiences:

1. Redness 
2. Irritation
3. Blurred vision
4. Itchiness
5. Burning sensation

Changing dietary habits cannot treat pterygium. However, it can help reduce the risk of pterygium. Some of the below-mentioned dietary habits can help in preventing pterygium.

1. Maintain a healthy diet: include plenty of vegetables, fruits and grains in the diet.

2. Go organic: organic food items contain more nutrients and minerals that are essential for the body.

3. Limit refined products: lower the amount of sugar and refined carbohydrates.

4. Avoid fast food and fried foods: These items contain unwanted fats that can worsen the condition.

5. Cut down caffeine intake (coffee), soft drinks and alcohol: These contain sugar that can increase the risk of a disease condition.