Laser Eye Correction Surgery : Will it Work for You?Written by Jenna Keys
Technology moves at alarmingly fast rates now, and where glasses or contact lenses have been required in past to correct vision deficiencies there is now an alternative. Laser eye correction is a relatively affordable procedure that means you wonít need to wear your reading glasses anymore and can correct virtually any eye problem. It is suitable for any adult with an eye problem and may be answer you are looking for.
What is Laser Eye Correction?
Laser Eye Correction, or refractive surgery as it is also known, is a quick procedure usually taking up to 15 minutes per eye. The actual laser treatment consists of less than 1 minute. During this process a laser scans your eyes pinpointing hundreds of unique points on your cornea. Once this is done, software used can determine exactly where fault lies and ascertain minor adjustments needed to restore your sight back to a reasonable level. The laser then reshapes cornea so that your eyesight becomes at least 20/40 vision, although in most cases it can be restored completely to 20/20 vision. Your surgeon will, of course, talk you through exact procedure before surgery commences and if you have any questions, do not be afraid to ask.
You will be administered with anaesthetic eye drops prior to any procedure and a subtle restraining device placed on your eyes so there is no danger of you blinking. The apparatus accounts for small eye movements, so even if you canít quite manage to stare at red light all way through procedure there shouldnít be a problem.
Most patients suffer from little or no discomfort and recovery time after procedure is very little. It is advised that on completion of correction you rest your eyes until next day, donít stare at a television or a computer and donít go anywhere where there is smoke or other pollutants. Next day you should be able to return to your normal daily life without need for glasses or contact lenses.
Exactly how effective is treatment?
Approximately 95% of patients have 20/20 vision or better following treatment and half have reported that their eyesight is better after treatment than when using glasses or contacts before. Ordinarily there is no need for further treatment because sight you have after correction is sight you will have for rest of your life. In fact, many clinics offer equivalent of a lifetime guarantee, so if you do need any enhancements you will receive them free of charge.
The Pathophysiology of TetanusWritten by Wong Lai Teng
Tetanus is an acute, often fatal disease caused by an exotoxin produced in a wound by Clostridium tetani. Clostridium tetani is a gram-positive, nonencapsulated, motile, obligatively anaerobic bacillus. It exists in vegetative and sporulated forms. Spores are highly resistant to disinfections by chemical or heat, but vegetative forms are susceptible to bactericidal effect of heat, chemical disinfectants, and a number of antibiotics.
Clostridium tetani is a noninvasive organism. It is found in soil and in intestine and feces of horses, sheep, cattle, dogs, cats, rats, guinea pigs and chicken. Manure-treated soil may contain large numbers of spores too.
Tetanus occurs after spores or vegetative bacteria gain access to tissues and produce toxin locally. The usual mode of entry is trough a puncture wound or laceration. Tetanus may also follow elective surgery, burn wounds, otitis media, dental infection, abortion and pregnancy. Neonatal tetanus usually follows infection of umbilical stump.
In presence of anaerobic conditions, spores germinate. Toxins,including tetanolysin (which potentiates infection) and tetanospasmin (a potent neurotoxin) are produced. Tetanospasmin, often referred to as tetanus toxin, causes clinical tetanus. The toxin produced is disseminated through bloodstream and lymphatic system. However, it does not enter central nervous system through this route, as it cannot cross blood brain barrier except at fourth ventricle. The toxin is exclusively taken up by neuromuscular junction, where it migrates retrograde transynaptically at rate 75-250mm/day, a process which takes 3-14 days, protected from neutralizing antitoxin, predominantly to inhibitory synapses to prevent release of acetylcholine.