December 13, 2024

Achieving Accurate Contact Lens Measurement

Accurate thickness measurement of contact lenses and contact lens molds are critical throughout the manufacturing and QA process to ensure customer acceptance and manufacturing yields. Manufacturing continues to face a workforce shortage of skilled technicians, and traditional contact lens measurement instruments require highly skilled, manual techniques. Non-contact metrology can help to reduce QA labor and increase the profitability of contact lens production. 

The Importance of Accurate Contact Lens Measurement

Accurate contact lens measurement is crucial for ensuring optimal vision and comfort. An effective testing protocol ensures product performance and can prevent issues such as discomfort, dryness, and potential damage to the eye. Properly measured lenses can also significantly improve visual acuity, providing a seamless and natural vision experience.

Poorly fitting lenses can lead to complications like corneal abrasions, infections, and other long-term ocular health issues. Therefore, investing in accurate measurement techniques is vital for both contact lens manufacturers and their customers.

Challenges in Traditional Contact Lens Measurement

Ophthalmic devices like contact lenses are subject to a number of inspection protocols, as defined by ISO 18369-3 for Ophthalmic Optics, including:

  • Contact Lens Material Inspection: to verify materials are as specified and approved by FDA 
  • Performance Testing: including UV protection level, wettability, specific gravity, and semi-permeability testing
  • Visual Inspection: including a check of color, lens diameter, optical zone diameter, base curve radius, edge quality, lens power, SAG, and thickness measurement.

Thickness measurements of contact lenses verify center thickness, edge thickness, and junction thickness. Contacts that are too thick can result in less air reaching the cornea, a primary cause of complications and discomfort. 

Traditional contact lens measurement methods including thickness gauges often involve manual techniques that rely heavily on the operator's skill and experience. Rehder low force contact measurement gauges and similar drop gauges must touch the lens, deforming the lens and impacting the accuracy of the reading, and require a dry measurement, increasing handling. These methods can be time-consuming and prone to human error, leading to inconsistent results and less-than-ideal lens manufacturing outcomes. 

SAG measurements are traditionally done with an optical comparator, by illuminating the lens from the side. These measurements are hard to read, subjective, and require highly trained technicians to get a good focus. 


Meet the Optigauge II for faster and more accurate testing of SAG and thickness, with optional index of refraction for materials testing.


Traditional metrology tools are also limited in their ability to capture detailed measurements. Factors such as corneal curvature, lens thickness, and diameter need precise evaluation to ensure a perfect fit. Conventional methods may struggle to provide the high level of accuracy required, resulting in less effective and potentially uncomfortable lens fittings. Digital, detailed measurements from non-contact thickness gauges like the OptiGauge II can also help seamlessly meet the requirements of traceability for medical device manufacturers. 

How OptiGauge II Revolutionizes Contact Lens Measurement

The OptiGauge II brings a revolutionary approach to contact lens measurement using advanced low-coherence interferometric technology. This device offers unparalleled precision, capturing detailed contact lens measurements in real-time.

Unlike traditional methods, OptiGauge II minimizes the risk of human error and delivers consistent, reliable results. Its high-resolution measurements allow for a comprehensive lens analysis, ensuring optimal comfort and vision quality. This innovation represents a significant leap forward in the field of contact lens manufacturing, providing both manufacturers and patients with a superior contact lens solution.

Enhancing Patient Satisfaction with Accurate Contact Lens Metrology

Accurate contact lens measurements significantly enhance patient satisfaction by providing lenses that fit perfectly, ensuring both comfort and optimal vision. Patients are more likely to experience fewer complications and higher overall satisfaction with their contact lenses.

Meet the Optigauge II: Watch the demo or discuss how it may fit in your manufacturing process

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