Readers, Bifocals or Progressives- what is the difference?

It is usual after the age of 40 to find your near focus is becoming more difficult. At this stage you would have developed an unpreventable condition called presbyopia. This is where you gradually lose your near focusing ability with age. If you aren’t already wearing glasses this may be a frightening reality but there are many options depending on your lifestyle and visual requirements.  

So what options are there to enable you to still see that restaurant menu or continue your hobby of knitting?

Readers

These will only be able to provide you with clear near vision. This is because the lens only allows you to focus at one particular working distance, usually 40cm. This would be ideal if you are wanting to complete near tasks for long periods of time such as reading, knitting or sewing. Remember that distance objects may appear blurry through your readers so you will need to take them off to look into the distance.

Bifocals

Bifocals consist of two lenses, one which allows you to see in the distance and the other up close. At around 50 years of age when you have lost most of your near focusing ability it can make intermediate objects blurry. This is where a third portion is added to provide an intermediate correction. These are called trifocal lenses and are helpful with tasks such as working on a computer.  

As simple as bifocals and trifocals sound, they can cause an image jump effect. This is due to shift in power of the near segment. There is a dividing line on the lens which can be seen in the public eye as a sign of ageing. This can make bifocals and trifocals cosmetically unappealing to some wearers. Despite this the dividing line helps guide the wearer on where to look and provides a large reading zone.

Progressives

Instead of placing different lenses together as is the case with bifocals and trifocals, progressives are one lens that provides continuous vision at all distances. This is due to a smooth increase in power from distance to near through the intermediate zone.  

The design of the lens can cause a slight ‘swim’ effect in the periphery of the lens. This may initially be disconcerting but after learning how to use them correctly your eyes quickly adapt with the lenses appearing clear and comfortable.. Unlike bifocals and trifocals there is no dividing line or image jumps due to the smooth transition in power through the lens., thus creating the most natural type of vision for those over 40 years.

The adjustment period

As with any change in prescription it requires time for your eyes to adjust and progressives are no different. Don’t be afraid to give them a go and following these steps will make the adjustment process easier: 

·       Wear your glasses as much as you can – this gives your visual system a better chance to adjust to the new lenses.

·       Practice moving your head to see objects in your periphery – if you just move your eyes you may experience blur through the edge of the lens. It is a good rule of thumb to point your nose directly at what you wish to look at.

·       Practice getting used to where your head should be when performing different visual tasks – If you are wanting to read keep your chin up and lower your eyes. If you are walking up or down stairs remember to drop your chin, so you are looking through the top portion of the lens.  

If you still have queries about these lens options book in for a comprehensive eye examination or feel free to drop in and discuss your visual requirements with one of our friendly team. The success of any pair of glasses is not just dependent on the prescription, but also the lens quality and technology along with the frame fit and adjustment.

We are always here to help and aim to give you the best vision possible.

Primitive Reflexes and Vision Development

What are Primitive reflexes?

We enter this world with neonatal or primitive reflexes. With the purpose of assisting an infant to survive and thrive in their new environment, primitive reflexes are a set of involuntary movements that occur in response to certain stimuli. You will have encountered these when you were last in the presence of a newborn but may not have given them too much thought. Some examples;

Palmar or grasping reflex- a baby will make a strong and persistent grip around an object placed in their palm; with this reflex disappearing around 6 months.

Plantar reflex- when the sole of the foot is stroked the big toe will move upwards and outwards with the other toes also spreading outwards. This reflex may be present up to 2 years.

Spinal Galant reflex- within the first 4-6 months if a baby is stroked along either side of their spine, their body will turn to the same side.

Moro or startle reflex- as the name suggest, when an infant is startled, for instance, by a loud noise, the arms and legs will be thrown outward in response. This reflex usually disappears around 2 months of age, but may persist up to 6 months. 

Why do we care about primitive reflexes?

While the reflexes play an important role in our adaptation to the world and in our early brain development, if a baby was to retain these reflexes the maturing of the neurological system may be delayed or disrupted. This may lead to behavioural, physical or learning difficulty as the child grows.

Vision development and primitive reflexes

The remarkable thing about primitive reflexes, is the fact they begin before the baby is even born and actually assist with the birthing process. As the baby continues to grow, they are essential for development of muscle tone and posture, head control and integration of our senses. As the baby develops further these involuntary reflexes are no longer required as they are replaced with more controlled responses as the baby ‘learns’ about the world. With timely integration of the reflexes, development of gross motor skills such as crawling, standing and walking occurs. Followed by fine motor skills of holding a pen, tying shoe laces and then the even more precise muscle control of eye movements and teaming. Thus preparing the child to have the physical ability to be able to learn to read when they start school.

Retained reflexes and behavioural optometry

If the primitive reflexes are not integrated they can get in the way of vision development and learning potential. Some examples of the effects of retained reflexes;

Spinal Galant- Poor concentration, fidgeting, decreased short term memory, attention deficit, discomfort with waistbands and sitting on a chair

Moro reflex- anxiety, emotional immaturity, impulsive, sensitive to noise and sensory overload

Tonic Labyrinth reflex- Letter reversals, difficulty sequencing, motion sickness, toe-walking

Symmetrical Tonic Neck reflex- hyperactivity, poor integration of upper and lower body

Asymmetrical tonic neck reflex- Poor co-ordination, learning disabilities, association with dyslexia

What can we do about retained primitive reflexes?

It is important to revisit the stage of development that may have been disrupted; this may entail for instance teaching a child to crawl again, or being able to ‘cross – pattern’ walk and then gradually building development to an age appropriate level. Behavioural optometrists and some occupational therapists with an interest in this area will be able to assist and create a therapy program to assist the child in maximising their potential!