question: How do optometrists decide which lenses are going to work for a baby's eyes?
comment: The machine (called an autorefractor) looks at the retina in the back of the child's eye. When the image on the retina is sharp, the prescription is right.
passages: In order to allow timely intervention, a system of monitoring is undertaken for infants at risk of developing ROP. These monitoring protocols differ geographically because the definition of high-risk is not uniform or perfectly defined. In the USA the consensus statement of experts is informed by data derived by clinical trials and published in Pediatrics 2006. They included infants with birthweights under 1500 grams or under 30 weeks gestation in most cases. The first examination should take place within the first 4 weeks of birth, and regular, weekly examination is required until it is clear that the eyes are not going to develop disease needing treatment, or one or both eyes develop disease requiring treatment. Treatment should be administered within a 48 hours, as the condition can progress rapidly.
   Some ophthalmologists, notably Ing and Helveston, favour a prescribed approach often involving multiple surgical episodes whereas others prefer to aim for full alignment of the eyes in one procedure and let the number of muscles operated upon during this procedure be determined by the size of the squint.
  
  2. Timing and outcome
   Section::::Implemented projects by country.:Canada.:Ontario.
  
  Thirteen teleophthalmology programs currently exist in Ontario. Two of the programs facilitate ophthalmology support for premature infants, screening for retinopathy of prematurity (RoP), using ophthalmologists at Sick Kids and McMaster University Medical Centre.
   Section::::Training, licensing, representation and scope of practice.:Europe.:Germany.
  
  Optometric tasks are performed by ophthalmologists and professionally trained and certified opticians.
  
  Section::::Training, licensing, representation and scope of practice.:Europe.:Greece.
   A 100-case audit of retinal screening by optometrists was performed in the remote areas of Western Australia. Projects are now being started base on this pilot experience.
  
  Section::::Implemented projects by country.:Canada.
  
  A number of teleophthalmology programs exist in Canada, including those in the provinces of Alberta, British Columbia, Manitoba, Newfoundland, Ontario, and Quebec.
  
  The cost of taking the images and of the ophthalmologist to interpret the images is covered by public-funded health care insurance. Typically a registered nurse or registered practical nurse is trained to dilate the patient's pupils and take the images.
   A small number of hybrid lenses exist. Typically these contact lenses consist of a rigid center and a soft "skirt". A similar technique is the "piggybacking" of a smaller, rigid lens on the surface of a larger, soft lens. These techniques are often chosen to give the vision correction benefits of a rigid lens and the comfort of a soft lens.
  
  Section::::Types.:Wear schedule.
   The parameters specified on spectacle prescriptions vary, but typically include the patient's name, power of the lenses, any prism to be included, the pupillary distance, expiration date, and the prescriber's signature. The prescription is typically determined during a refraction, using a phoropter and asking the patient which of two lenses is better, or by automated refractor, or through the technique of retinoscopy. A dispensing optician will take a prescription written by an optometrist or ophthalmologist and order and/or assemble the frames and lenses to then be dispensed and sold to the patient.
  
  Section::::Components of a sphero-cylindrical correction.
   MRIs and CTs can be used to scan the brain and orbits. Radiologists use this to assess the internal structures of the globe, the optic nerve and extraocular muscles, and brain anatomy.
  
  Section::::Postnatal diagnosis.:Examination.
  
  Physicians, specifically ophthalmologists, can examine the child and give a correct diagnosis. Some will do molecular genetics tests to see if the cause is linked with gene mutations. 
   Retinal examination with scleral depression is generally recommended for patients born before 30–32 weeks gestation, or 4–6 weeks of life, whichever is later. It is then repeated every 1–3 weeks until vascularization is complete (or until disease progression mandates treatment).
  
  Section::::Screening.:Procedure.
   Ultrasounds can be used to diagnose anophthalmia during gestation. Due to the resolution of the ultrasound, it is difficult to diagnose it until the second trimester. The earliest time to detect anophthalmia this way is approximately 20 weeks.
  
  Section::::Prenatal diagnosis.:Amniocentesis.
  
  It is possible to diagnose prenatally with amniocentesis, but it may not show a correct negative result. Amniocentesis can only diagnose anophthalmia when there is a chromosomal abnormality. Chromosomal abnormalities are only a minority of cases of anophthalmia.
  
  Section::::Postnatal diagnosis.
  
  Section::::Postnatal diagnosis.:MRI/CT.
   Ophthalmologists use various approaches to analyze the results of refractive surgery, and alter their techniques to provide better results in the future. Some of these approaches are programmed into the devices ophthalmologists use to measure the refraction of the eye and the shape of the cornea, such as corneal topography.
  
  Section::::Risks.
   The test type and eye are firstly selected and the patient's details are entered, including their refractive error. The Analyser will provide a lens strength and type (either spherical and/or cylindrical), if required for the test. In these instances, wire-rimmed trial lenses are generally used, with the cylindrical lens placed closest to the patient so the axis is easily read. The clinician can alter the fixation targets as per necessary (see Fixation Targets for advice).
   Section::::Training, licensing, representation and scope of practice.:North America.:Canada.:Scope of Practice.
  
  Optometrists in Canada are trained and licensed to be primary eye care providers. They provide optical and medical eye care. They are able to diagnose and treat most eye diseases and can prescribe both topical and oral medications
  
  Section::::Training, licensing, representation and scope of practice.:North America.:United States.
   Section::::Appearance and construction.
   In addition, there is an accommodating lens that was approved by the US FDA in 2003 and made by Eyeonics, now Bausch & Lomb. The "Crystalens" is on struts and is implanted in the eye's lens capsule, and its design allows the lens' focusing muscles to move it back and forth, giving the patient natural focusing ability.
   Advancements in mobile-based automated pupillometry have been made in recent years to accommodate for the growing number of mobile phones being used in healthcare. Notably, brightlamp, Inc. has secured the first intellectual property relating to mobile quantitative pupillometry and has subsequently released their first product, Reflex. Reflex is the first commercially available mobile pupilometer for iOS that does not require any additional hardware for usage.
   Pediatric ophthalmologists focus on the development of the visual system and the various diseases that disrupt visual development in children. Pediatric ophthalmologists also have expertise in managing the various ocular diseases that affect children. Pediatric ophthalmologists are qualified to perform complex eye surgery as well as to manage children's eye problems using glasses and medications. Many ophthalmologists and other physicians refer pediatric patients to a pediatric ophthalmologist for examination and management of ocular problems due to children's unique needs. In addition to children with obvious vision problems, children with head turns, head tilts, squinting of the eyes, or preferred head postures (torticollis) are typically referred to a pediatric ophthalmologist for evaluation. Pediatric ophthalmologists typically also manage adults with eye movement disorders (such as nystagmus or strabismus) due to their familiarity with strabismus conditions.
   From the measurements taken, the specialist will write an eyeglass prescription that contains at least 3 numerical specifications for each eye: sphere, cylinder, and axis, as well as pupillary distance (distance between eyes), and, rarely, prism for one or both eyes.
   Lenses with different replacement schedules can be made of the same material. Although the materials are alike, differences in the manufacturing processes determine if the resulting lens will be a "daily disposable" or one recommended for two or four week replacement. However, sometimes manufacturers use absolutely identical lenses and just repackage them with different labels.
  
  Section::::Manufacturing.
  
  Typically, soft contact lenses are mass-produced, while rigids are custom-made to exact specifications for the individual patient.
  
  BULLET::::- Spin-cast lenses – A soft lens manufactured by whirling liquid silicone in a revolving mold at high speed.
   The Association of Regulatory Boards of Optometry (ARBO) assists these state board licensing agencies in regulating the practice of optometry.
  
  Section::::Training, licensing, representation and scope of practice.:North America.:United States.:Licensing.
  
  Optometrists must complete all course work and graduate from an accredited College of Optometry. This includes passage of all parts of the national board examinations as well as local jurisprudence examinations, which vary by state.
  
  Section::::Training, licensing, representation and scope of practice.:North America.:United States.:Education and Training.
   Corrective lenses provide a range of vision correction, some as high as +4.0 diopter. Some with presbyopia choose varifocal or bifocal lenses to eliminate the need for a separate pair of reading glasses; specialized preparations of varifocals or bifocals usually require the services of an optometrist. Some newer bifocal or varifocal spectacle lenses attempt to correct both near and far vision with the same lens.
   When recommending a progressive lens design, an eyecare practitioner will usually ask the customer some questions about their lifestyle, which coupled with prescription restrictions or recommendations and cost can establish the suitability of various models of progressive lens. Different lenses have different glazing restrictions, lens material availabilities, maximum and minimum fitting heights, prescription ranges and as such the variation in quality between higher and lower end varifocal lenses is considerable.
  
  Section::::Miscellaneous.
   A vision therapist, usually either an orthoptist or optometrist, works with patients that require vision therapy, such as low vision patients. Commonly, vision therapy is performed in children who develop problems with their vision mostly because they are using their eyes up close. This type of therapy is however generally used in patients who need visual correction but for whom the corrective lenses are not enough to reverse the condition. Visual therapy in children is performed by optometrists who specialize in children's eye care. To specialize in vision therapy, doctors must complete extensive post-graduate training beyond their optometric degree, at which time they are eligible to sit for their national boards to become fully certified as specialists in children's vision. A doctor's title after passing the national board in vision therapy is Fellow in the College of Optometrists in Vision Development, or F.C.O.V.D. Optometrists who provide vision therapy but who have not yet sat for their certification exams are board-eligible Associates in the College of Optometrists in Vision Development.
   Recent developments show new innovations from EyePrintPRO pro a scleral lens design where a mold is taken of the cornea and sent to a lab where 3D software designs a lens to fit over every area of the patients specific cornea, other advances include experimental wavefront optics incorporated into scleral lenses which several others manufacturers like iZon are working on to further correct higher order aberrations, current scleral lenses without any additional optics correct 70 percent or more of higher order aberrations varrying between patient, these and other technologies look forward to correct all aberrations.
  
  Section::::External links.
   Optician
  
  An optician, or "dispensing optician", is a technical practitioner who designs, fits and dispenses corrective lenses for the correction of a person's vision. Opticians determine the specifications of various ophthalmic appliances that will give the necessary correction to a person's eyesight. Some registered or licensed opticians also design and fit special appliances to correct cosmetic, traumatic or anatomical defects. These devices are called shells or artificial eyes. Other registered or licensed opticians manufacture lenses to their own specifications and design and manufacture spectacle frames and other devices.
  