Strabismus, commonly known as crossed eyes or an eye turn, is a condition where the eyes do not properly align. This misalignment means the eyes look in different directions, which can be constant or intermittent. It is caused by an issue with the neuromuscular control of the eye muscles, preventing the eyes from working together. Many individuals with strabismus wonder if contact lenses can provide a suitable alternative to glasses for vision correction and management.
Understanding Strabismus and Vision Correction
Strabismus often occurs alongside significant refractive errors, such as hyperopia, myopia, or astigmatism. Correcting these focusing issues is a mandatory step in the overall treatment plan. Ensuring a clear image is focused onto the retina provides the brain with the best chance to align the eyes, particularly in accommodative esotropia, where the inward turn relates to focusing effort.
The specific direction of the eye turn categorizes the strabismus: esotropia is an inward turn, exotropia is an outward turn, and hypertropia or hypotropia are upward or downward turns. Uncorrected refractive errors can also lead to amblyopia, or “lazy eye,” where the brain favors the stronger eye and ignores the image from the misaligned eye. Early vision correction is important not only for clarity but also to prevent or treat this loss of vision development.
Contact Lenses for Standard Refractive Needs
Contact lenses are a highly effective option for correcting the common refractive errors often associated with strabismus, essentially functioning as a replacement for standard corrective glasses. Both soft and rigid gas permeable (RGP) lenses can successfully neutralize the prescriptions for myopia, hyperopia, and astigmatism. For patients with high prescriptions, contact lenses can offer superior vision correction compared to glasses.
This improved vision is due to contact lenses sitting directly on the eye, which eliminates the distortion and magnification effects present with thick spectacle lenses. This is particularly beneficial for individuals with anisometropia, a condition where the two eyes have significantly different prescriptions. While glasses create images of different sizes (aniseikonia) in these cases, contact lenses reduce this size difference, potentially improving the eyes’ ability to work together.
Astigmatism, a common refractive error in strabismus patients, is corrected using toric contact lenses. These lenses have two different powers to compensate for the irregular corneal shape and must be stable on the eye to maintain their orientation. This stability is achieved through specific weighted or thinned zones within the lens design. RGP lenses are also excellent for correcting high or irregular astigmatism, often providing a sharper image than soft lenses.
Specialized Contact Lenses for Strabismus Management
Beyond standard vision correction, specific contact lenses are designed to manage the misalignment and associated visual symptoms. One specialized application involves the use of occlusion lenses, which are opaque or blacked-out contacts used to block vision in one eye. These lenses are often employed in place of an eye patch to treat amblyopia by forcing the brain to use the weaker, misaligned eye. The contact lens provides a more discreet and cosmetically acceptable alternative to traditional patching, which can increase patient compliance, particularly in older children and adults.
Another advancement is the use of prismatic contact lenses, which are designed to incorporate a prism power directly into the lens material. A prism works by bending light before it enters the eye, effectively shifting the image to compensate for small degrees of eye misalignment. These custom-made lenses are primarily used to manage diplopia, or double vision, which results when the brain cannot fuse the two images received from the misaligned eyes.
Soft directional prismatic contact lenses can successfully correct small-angle strabismus causing double vision, often offering a quality of vision superior to that of prismatic glasses. The prism element helps the eyes align the images, allowing the brain to fuse them into a single, comfortable visual experience. These specialized lenses are a complex, custom solution and are reserved for small deviations, usually up to 8 prism diopters.
Essential Safety and Fitting Considerations
Obtaining contact lenses for strabismus requires a comprehensive consultation and fitting performed by a qualified eye care professional experienced in strabismus and binocular vision. The fitting process for specialized lenses, especially prismatic contacts, is complex because the lens must maintain a precise, stable position for the prism to work. Rotation of the lens will change the direction of the prism, which can lead to discomfort or ineffective correction.
The eye care professional must closely monitor the patient’s eye deviation and overall binocular vision after the lenses are dispensed. Changes in the strabismus angle over time may necessitate adjustments to the lens prescription.
Proper hygiene and lens care are important, as strabismus patients may face unique challenges, such as difficulties with depth perception that could affect lens handling and insertion. A professional will provide detailed instruction and ensure the chosen lens type is appropriate for the individual’s specific condition, visual needs, and lifestyle.