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When PPD is smaller than FPD

• Decentration PER lens is a POSITIVE NUMBER
• The lenses are decentered inward TOWARDS the nasal

When PPD is smaller than FPD

FORMULA for CALCULATING decentration PER lens is

Decentration per lens = FPD ( Frame pupillary Distance) – (PPD) Patient pupillary distance/ 2

Formula for calculating decentration per lens is

Decentration per lens = FPD ( Frame pupillary Distance) – (PPD) Patient pupillary distance/ 2

Myopia is a CONDITION where person is unable to see far objects, and it may CAUSE DUE to

• When eyes crystalline lens becomes too convex
• When the eyeball lengthens from front to BACK
• It can be IMPROVED by using a concave lens.

Myopia is a condition where person is unable to see far objects, and it may cause due to

1 DIOPETER= 1/focal LENGTH.

1 diopeter= 1/focal length.

Lens are classified into two

Manually OPERATED: Vertometer, LENSOMETER

COMPUTERIZED: Topcon 2000, HUMPHREY.

Lens are classified into two

Manually operated: Vertometer, Lensometer

Computerized: Topcon 2000, Humphrey.

Lensometer is a DEVICE USED to characterized the properties of lens LIKE

• Power of the lens
• Optical center location
• Major reference point location
• CYLINDER AXIS orientation
• Prism power/ direction

Lensometer is a device used to characterized the properties of lens like

Astigmatism is a MEDICAL condition where the image created on the RETINA is not EQUAL in all meridians, CAUSING blurring.

Astigmatism is a medical condition where the image created on the retina is not equal in all meridians, causing blurring.

• Lubricants for eye dryness: Many PEOPLE have eye dryness problem, they can use lubricants to keep their eye wet
• Use PRESERVATIVE-free solution: Certain people are sensitive to the chemical used in the eye lens as preservative, for them they can use preservative free solution
• Saline solution: It is used for storing and rinsing contact lenses
• DAILY cleaner: It is used as a disinfectant
• Multipurpose solution: This solution can be used for all purposes like rinsing, cleaning, disinfecting and storing
• Enzymatic cleaner: This solution is used to TAKE away the PROTEIN accumulated from the surface of the contact lenses.

• People who are working in industries like construction SITE or HEAVY engineering, where there is a lot of debris, should avoid wearing contact lenses
• People who are having dry eye PROBLEMS
• People who are compromising the safety MEASURES for USING contact lens

• Don’t wear contact lenses overnight, it increases the risk of infection and damaging cornea
• Don’t wear contact lenses while SWIMMING or taking shower, the micro-organism or chemical present in them may cause infection
• Don’t reuse contact lens solution, it may increase the risk of eye infection
• Make sure every TWO or three MONTHS you are REPLACING your contact lenses
• If contact lens brings irritation to the eye, then see DOCTOR immediately
• Never use saliva as a lubricant for your contact lenses.

The USAGE of both these lenses are same but, progressive lenses with their MULTIPLE focal distances easily adapt to the environment or adjust your eyes for the VISION. While, the bifocal lenses will TAKE some time to adjust the vision from a DISTANCE to nearby or vice versa. One setback with progressive lens is that it creates a vision that is slightly distorted compared to Bi-focal lenses.

The usage of both these lenses are same but, progressive lenses with their multiple focal distances easily adapt to the environment or adjust your eyes for the vision. While, the bifocal lenses will take some time to adjust the vision from a distance to nearby or vice versa. One setback with progressive lens is that it creates a vision that is slightly distorted compared to Bi-focal lenses.

BIFOCAL lenses are designed into TWO separate PARTS, which gives the user the freedom of seeing objects NEARBY and farsighted without changing the glasses.

Bifocal lenses are designed into two separate parts, which gives the user the freedom of seeing objects nearby and farsighted without changing the glasses.

The TYPES of lenses available are

• Polycarbonate lenses
• Trivex lenses
• High INDEX PLASTIC lenses
• Aspheric lenses
• Photochromic lenses
• Polarized lenses

The types of lenses available are

Detached retina is a condition in which PART of the retina detached from the inside of the eye. The early SYMPTOMS of this condition include falling curtains in FRONT of eyes followed by new flashing LIGHTS.

Detached retina is a condition in which part of the retina detached from the inside of the eye. The early symptoms of this condition include falling curtains in front of eyes followed by new flashing lights.

Polycarbonate is a lens MATERIAL that is characterized by its lightness, HIGH refractive INDEX, impact resistance and U.V absorption.

Polycarbonate is a lens material that is characterized by its lightness, high refractive index, impact resistance and U.V absorption.

A CATARACT is a medical condition where person’s eye LENS becomes OPAQUE due to the aging or DISEASE like diabetes or hypertension.

A cataract is a medical condition where person’s eye lens becomes opaque due to the aging or disease like diabetes or hypertension.

Such condition is REFERRED as HYPEROPIA, where a PERSON can’t see nearby OBJECT.

Such condition is referred as Hyperopia, where a person can’t see nearby object.

Intraocular PRESSURE is used to REFER the pressure exerted INSIDE the EYEBALL, which keeps the wall taut.

Intraocular pressure is used to refer the pressure exerted inside the eyeball, which keeps the wall taut.

Tools used by an optician are

• Bracing tools
• ANGLING pliers
• BRIDGE adjustment tools
• Lens adjustment pliers
• Frame warmers
• Files
• SCREWDRIVERS and wrenches
• Ophthalmoscope
• Lens CLOCK
• Lens thickness calipers
• CORNEAL refraction pupillometer

Tools used by an optician are

OPHTHALMOLOGIST: It is a MEDICAL practitioner, who diagnose and treats all eye diseases, perform surgeries and treats all eye diseases

Optometrist: It is a health care PROFESSIONAL who gives primary vision care. Their primary role INCLUDES performing eye and vision test, prescribing correct lenses, diagnosis certain eye abnormalities and prescribing medication for certain eye diseases

Optician: They are trained professionals who design, verify and fit eyeglass frames and lenses. They do not operate or DISPENSE prescription or perform any kind of vision test; they only work with eye lenses and frames to correct eyesight.

Ophthalmologist: It is a medical practitioner, who diagnose and treats all eye diseases, perform surgeries and treats all eye diseases

Optometrist: It is a health care professional who gives primary vision care. Their primary role includes performing eye and vision test, prescribing correct lenses, diagnosis certain eye abnormalities and prescribing medication for certain eye diseases

Optician: They are trained professionals who design, verify and fit eyeglass frames and lenses. They do not operate or dispense prescription or perform any kind of vision test; they only work with eye lenses and frames to correct eyesight.

Amblyopia is a CONDITION where one of the two eyes has POOR vision or AMBLYOPIC. This condition is ALSO REFERRED as lazy eyes.

Amblyopia is a condition where one of the two eyes has poor vision or Amblyopic. This condition is also referred as lazy eyes.

• Measure, design, FIT and frames according to the optical PRESCRIPTION
• Help the customer in selecting frames
• Ensuring that the lenses are according to the specifications
• Prepare instructions and work ORDERS for GRINDING lenses and fabricating eyeglasses
• Maintaining record of customers work orders, prescription, and payments
• Performing duties like submitting patient INSURANCE information, performing simple book-keeping and tracking inventory & sales
• Demonstrate customers about how to insert and remove lenses
• Train the fellow student opticians