Readers’ Forum

Digital Consulting for GP Lens Fitting

readers' forum

Digital Consulting for GP Lens Fitting


Ultra-talented contact lens fitters are rare exceptions. They're the ones who sometimes get their hands dirty modifying the final lens to achieve the best contact lens-to-cornea fitting relationship, or they can carefully observe the fluorescein pattern of a diagnostic lens and understand the changes to make in the final lens to order from the manufacturer.

The ideal situation is when a contact lens practitioner has a substantial understanding about manufacturing principles and lens designs. He generally will have a good idea about what specific modifications are needed in the lens-to-cornea relationship.

Of course not all contact lens practitioners have acquired this knowledge; many have a limited understanding of the possibilities and often count on laboratory technicians to make the changes they ask for. Such changes are often limited because many technicians lack experience and understanding of the lens-to-cornea relationship. Many don't have adequate training and education in tear film evaluation, corneal conditions and topography.

Topography's Role

People sometimes think that I'm against corneal topography technology, especially when it's applied to irregular corneal conditions. I am completely supportive of using such technology and its contact lens software, although I believe that it will always play a limited role in the success of a specialty fitting. Today's corneal topography technology features 3D images, tear layer volume and disposition, pre-programmed special lens designs and encrypted proprietary lens designs of important manufacturers and brands. That's great. What contact lens fitters, contact lens manufacturers and corneal topographer manufacturers have in common is a desire for the best patient satisfaction, comfort, corneal health and the best acceptable visual acuity.

The problem with the extensive use of high technology coupled with the lack of the experience mentioned previously is that a wide variety of variables affect the lens-to-cornea fitting including palpebral fissure, tear quality, gravity, lens and material physics, atmospheric conditions, temperature, eye movements, different eye conditions and much more. We can't depend exclusively on top corneal topography technology when we manage irregular cornea conditions. Lens fitters must have adequate training and experience in GP fitting and diagnostic lens evaluations. And if they understand the manufacturing principles, it will help even further.

Helping With Specialty Fits

The vast majority of contact lens practitioners don't have such expertise and knowledge of principles. When I realized that I was in a position to help these practitioners succeed with their fittings, I had a discussion with my father, Saul Bastos, MD, who was one of the most experienced lens fitters I knew. He used to fit about 20 to 25 special lens designs a day. He taught me the principles of contact lens fitting, especially for irregular cornea conditions, which supplemented my knowledge in contact lens manufacturing principles.

My father was concerned and uncomfortable when some ophthalmologists asked for my help to resolve some cases; he used to say that the doctors should know what to do and not ask me what to do. But I wanted to help those practitioners succeed so I could help more patients have a better quality of life, solve their vision needs and offer the real possibility of visual rehabilitation.

Today, I have the responsibility to run my father's clinic, Instituto de Olhos Dr. Saul Bastos (IOSB), and Ultralentes, a GP contact lens laboratory in Brazil that researches and manufactures specialty GP lens designs.

We have some special lens designs for irregular cornea conditions such as keratoconus, pellucid marginal degeneration, postpenetrating keratoplasty (postgraft), post-RK/PRK/LASIK sequelae and post-trauma. These lens designs are Ultracone, Ultracone Mini-Scleral (semi-scleral) and Ultraflat. They are multi-aspheric GP lens designs with different eccentricity values. During the last few years we've successfully fit keratoconus patients with base curves as steep as 75.00D.

We help practitioners with what I call The Digital Consultory. Practitioners take digital images of fluorescein patterns with our diagnostic lens designs and send the images to our lab via the Internet. We then have a conference about the case while we both observe the image.

Today's Digital Consultory consists of images of fluorescein patterns as well as video clips. I ask practitioners to send pictures in both white and cobalt blue lights in wide and slit view. This helps in determining the specific changes we can apply during the manufacturing process to improve the fitting. Most slit lamps today have the option of attaching an integrated system of digital photography. If practitioners don't want to spend this money, I encourage them to buy a digital camera that fits in the ocular eye piece of their biomicroscope. The only disadvantage of this is that the practitioner will have to hold the camera with one hand while operating the slit lamp with the other, but it's not difficult to master this task.

Troubleshooting Irregular Fits

When fitting an irregular cornea, it's quite common to face air bubbles, apical touch, intermediate and peripheral bearing, lack of movement, lens positioning problems or insufficient lacrimal exchange. Using digital consulting can improve the next lens because I can identify the necessary changes the lens needs during the manufacturing and finishing cycles, accordingly to the individual needs of each patient. CLS

Mr. Bastos is the director of Instituto de Olhos Dr. Saul Bastos (IOSB) and of a GP contact lens laboratory Ultralentes, both based in Brazil.