In the design and prescribing of contact lenses there are a plethora of contact lens options for the normally shaped eye. As eye care practitioners, we are presented with unique situations where either the corneal anatomic features and/or the patient's refractive needs fall outside of the typical “off-the-shelf” soft contact lens and special consideration, such as a custom soft contact lens, must be made. This case presentation highlights the utilization of soft contact lens parameters found outside the typical diagnostic fitting set.
A 30-year-old female presented to the clinic for contact lens fitting and evaluation. She had habitually worn corneal GP contact lenses, however her overall comfort and visual consistency was less than ideal. She had a history of bilateral microphthalmia with secondary high hyperopia.
Her central K values were OD 55.62 @ 101 / 54.50 @ 011 and OS 55.12 @ 080 / 54.12 @ 170. Her horizontal visible iris diameter as measured by the Medmont corneal topographer was 10.3mm. Her manifest refraction was OD +19.25 DS 20/100 and OS +20.00 DS 20/70.
The high amount of plus power in her habitual corneal GP contact lenses created a center of gravity that was so far forward, thus driving the GP lens downward (reference image below). This issue created intolerance to GP wear. Therefore, it was decided to trial custom soft contact lenses in an attempt to better center the lens and provide better overall comfort. With her small horizontal visible iris diameter (10.3 mm) and highly curved corneas (55 diopter average) it was decided to order custom soft contact lenses from SpecialEyes.
After utilizing the SpecialEyes Arc Length Calculator the appropriate base curve, power, and diameter was ordered and the patient was asked to return to clinic in one week for a dispensing visit. At her 2 week office visit she reported much improved overall comfort and more stable vision.
Through the understanding of this patient’s unique corneal features, her refractive error, and the utilization of the SpecialEyes Arc Length Calculator we were able to greatly improve her comfort and overall visual status with custom soft contact lenses from SpecialEyes. If you are interested in understanding how different corneal anatomic features impact sagittal height and the possible need for a custom soft toric or sphere contact lens, read my blog post “Measuring Anatomic Features and Sagittal Height for Custom Soft Contact Lenses”.
Matthew Lampa, OD, FAAO
Dr. Lampa is an Assistant Professor of Optometry at Pacific University and a consulting optometrist to SpecialEyes.