In one sentence, describe what the following article is about: A topographer is a newer version of the keratometer. Your doctor will have you sit at a table and look into a bowl. This bowl's inner surface is covered in a pattern of concentric rings. A digital camera sits at the base of the bowl and charts the cornea's surface by measuring the reflected pattern in the eye. This basically creates a contour map of your eye, and it's an excellent technique for measuring irregular astigmatism. Most corneal topography tests measure 8,000 to 10,000 points on the cornea, making it the most accurate keratometry test. Other advanced ways of measuring astigmatism include autorefractors that measure refraction, and the IOLMaster that makes extensive measurements of the interior and exterior of the eye. The IOLMaster is usually used before cataract surgery. The Placido disc is an old-fashioned, hand-held device that is shaped like a giant lollipop. The disc has several sets of concentric circles painted on one side, and is used to measure the regularity of your cornea's surface. Your doctor holds the disc up to their own eye with the rings pointed towards you, and they look into your eye. Sit still and look straight ahead. The image of your cornea reflects back, and where there is irregular shape it makes the concentric rings look distorted to your doctor. This old-fashioned method can help to diagnose keratoconus, a disorder that causes irregular astigmatism due to thinning and protruding of the cornea. The shape of your posterior cornea (the back surface of the cornea) can influence the severity of your astigmatism. Keratometry can only measure the front of your cornea, but Scheimpflug imaging uses tomography to get more accurate readings of how thick your cornea is and what the back of it looks like. This method can be helpful in predicting how successful surgery may be in correcting your astigmatism.
Summary: Use a corneal topographer for more precise measurements. Try a Placido disc for irregular astigmatism. Use a Scheimpflug device to measure the posterior cornea.

In one sentence, describe what the following article is about: For this method, you will need a clean round container like a coffee can or formula can, balloons, electrical tape or masking tape, and rubber bands (optional). Use your fingers to open the balloon up and expand it so it fits over the top of the can. Do not blow it up, you want to use a limp balloon. Using the scissors, cut small holes into the balloon. They do not need to be uniform or perfect, as they are more for decoration. Double layering the balloons will make the drum more durable, and the holes in top layer will add a fun decorative effect. You can also use rubber bands and simply place them around the can to keep the balloons attached. Or hand them to your little one and let them test them for you. If you'd like to add more weight to the drums, you can fill the container up with a handful of rice or dry lentils before you stretch the balloon on the top of the container. Make drum sticks out of pencils and tissue paper or simply use your hands to drum along to your favorite song.
Summary: Gather your materials. Stretch the balloon around the can. Lay another balloon flat on a hard surface. Stretch the cut up balloon on top of the balloon on the can. Wrap tape around the can to secure the balloons. Try out the drums.

In one sentence, describe what the following article is about: Perfumes, scented lotions, and scented laundry detergents are popular with many. People who use such products, however, may not realize the effect certain scents have on others. Work to educate friends, family members, and co-workers on scent sensitivity. Let them know what they can do to help you deal. Be courteous as you talk to others about your sensitivity. Many people have not heard of scent sensitivity, and may be confused as to what it is. Have patience and explain yourself slowly. If you have an official doctor's diagnosis, it can be helpful to let people know what precise condition is causing your sensitivity. For example, you may have an allergy to a particular chemical that's commonly used in scented products. You can also refer people to outside resources. If you know a website that discusses scent sensitivity, advise people to check out that site. Scent sensitivity can be a real problem at work, school, or elsewhere. If you live or work with others who use a lot of scented products, politely talk to them about your issues. You can respectfully request that they minimize use of certain products near you. Try to approach people in a friendly fashion. People don't want to feel like they're being scolded. For example, you can approach a co-worker and say something like, "Clara, I wanted to ask you about something. As you know, I have a scent sensitivity. If you could leave your scented lotion at home, I would really appreciate that as the smell can trigger asthma attacks. I don't want you to feel bad, and I'm sorry if it's an inconvenience, but I just want to be able to work effectively." If unwanted scents are a major issue at work, talk to your boss. There may be a policy in place in your office regarding the use of potential allergens. Many people will take your request to cut back on scented products as a personal judgment. A significant other may, for example, think you dislike the smell of their perfume and are trying to be polite. Calmly explain the issue is not personal, but it's a medical concern. Make sure the other person knows it's about the scent's effect on you. You can say something like, "It has nothing to do with you. I get allergy attacks walking by Bath and Body Works in the mall sometimes." Reassure the other person there are no hard feelings. You simply do not want to be routinely exposed to an allergen. If your scent sensitivity is causing problems at work, talk to your boss. You may be able to get them to accommodate your needs with a better work environment. You could request an air purifier in your office, for example, or a cubicle near a window. A more flexible schedule can also help you cope with scent sensitivity. Schedule a meeting with your boss and explain the issue you're having. Ask him or her if a flexible schedule would be possible to accommodate your needs. There are a variety of ways a flexible schedule can help you cope with scent sensitivity. You could work from home certain days or Skype into meetings. You could also come into work earlier or later some days, minimizing the time you spend with other coworkers who may use products that trigger your sensitivity.
Summary:
Educate others about scent sensitivity. Ask people politely to minimize their use of certain products. Explain it is not personal. Ask your boss about altering your work environment. See if you can have some flexibility in your work schedule.