How to select perfect spectacles

Determining facial wrap

Broadly there are six face shapes that we observe around the world.

• Oval shape
• Round shape
• Square shape
• Rectangle shape
• Triangular shape
• Heart shape

Importance of frame selection

• Value for expertly prescribed spectacle lenses
• Vision and comfort
• Good cosmetic appearance
• Frame adjustment
• Professional accordingly

Frame selection

According to demand

• Age group: Small children, young adult, old adult
• Profession: House wife, shopkeeper, medical practitioner, drivers, field worker
• Refractive error: minus vs plus, low vs high
• Special purpose frame: ptosis frame, sport spectacles

Boxing system

• In 1962 the optical manufacturers association adopted the boxing system to provide a standard for frame and lens measurement that greatly improved upon the accuracy of previous systems.
• The boxing system is based upon the idea of drawing an imaginary box around a lens shape with the box’s sides tangent to the outer most edges of the shape.

Pre dispensing measurement

• Facial wrap
• Pantascope tilt
• Vertex distance
• IPD measurement
• PD rular
• Pupilometer
• Pen torch

Pupilometer

Procedure:

• Hold the instrument in both hands and rest the pupilometer on patient’s face
• Ability to vary working distance from 20 cm to infinity
• Internal hairline moved until line and corneal reflection are coincident
• Corneal reflection typically located nasal to pupil center
• Mark the patient corneal reflex in marker

Counselling

Lens Materials

• Glass
• Plastic
• Hi-index etc

Lens Design

• Single vision
• Bifocal
• Executive
• Progressive etc