It’s no secret that scleral lenses have become an exciting opportunity in the specialty contact lens industry. The goal of prescribers is to provide a comfortable lens that keeps the cornea healthy and the patient seeing well. That seems easy enough, but as the applications of scleral lenses increase, so do the number of hurdles that scleral lens prescribers may encounter. Common vision issues include vision fluctuation and post-lens tear layer fogging. Patients may also comment about lens discomfort, edge awareness, and difficulties with application and removal. These obstacles may appear overwhelming, but thankfully our scleral lens toolbox is a full one. Let’s review some tips and tricks for these common fitting hurdles.
VISION CONSISTENCY AND CLARITY
The first step in providing great vision for scleral lens wearers is to properly care for your diagnostic lenses. This will provide the most accurate refracting surface for reliable over-refractions. Prior to lens application, clean the diagnostic lenses with a GP lens cleaner. In our experience, alcohol-based solutions are particularly effective; however, they cannot be used when the lens is surface coated. It is important to rinse the cleaner from the lens with sterile saline and to apply few drops of a conditioning solution on the front surface before placing it on a clean plunger.
Alternatively, many practitioners choose to store their lenses “wet.” This means that after appropriate cleaning and disinfection, lenses are stored in conditioning solution (or in GP multipurpose solution) until their next use. Storing lenses wet may yield better initial wettability, comfort, and quality of the over-refraction. If lenses are stored in conditioning solution, it is important to replace the storage solution every 30 days (or per manufacturers’ guidelines). This can often be a tedious task and also uses a copious amount of solution, which is why many practitioners choose to store their diagnostic lenses dry. After the evaluation, all diagnostic lenses should be disinfected, verified, and stored.
If visual acuity is lower than expected when the diagnostic lens is applied, the first step should be to quickly evaluate the lens on-eye for a bubble in the line of sight, followed by evaluating the lens surface for proper wettability. If there is a bubble, the lens must be removed and reapplied. If the surface is not wetting well (Figure 1), the lens can be removed and re-cleaned; alternatively, the “squeegee method” can be utilized in which a drop of conditioning solution is placed on the blunt end of the plunger, which is then applied to the lens surface. Move the plunger back and forth across the lens surface to remove oily residue and to improve surface wettability. If no bubble is noted and the lens appears to be wetting well, the next step would be determining the lens over-refraction.
When patients return for follow-up care reporting variability in vision, it’s important to review at-home care of the lenses to ensure that the lenses can perform their best. A common error made by patients is confusing their preservative-free filling solution with soft contact lens saline, thinking that they are one in the same. This exposure to preservatives for multiple days can lead to corneal irritation and visual disturbance.
Another important step that patients may omit is the need to keep their plunger clean. The plunger surface can transfer oils and other debris to the lens, which changes the way that the surface of the lens interacts with the tear film. Plungers can also harbor unsafe bacteria, viruses, and fungi, which can be detrimental to eye health. It is our recommendation that patients should be instructed to clean their plungers daily with isopropyl alcohol wipes. This will help minimize the risk of eye infections.
Another cause of variable vision in scleral lens wearers is a poor-quality tear film. As many dry eye patients experience a significant improvement in symptoms with scleral lens wear, it is often forgotten that they still have a dry eye disease with a poor-quality tear film and that they need to continue to work on their tear layer for best vision. Encourage use of artificial tears, medications, and at-home lid/meibomian gland care as an essential part of successful lens wear. Educating patients about the importance of managing dry eye disease is critical to their long-term success with scleral lenses.
Lens wettability issues (Figure 2) can often lead to poor and fluctuating vision and to the frustration of constantly having to remove the lenses during the day. Identifying and managing the cause of the decreased wettability is extremely important and can dramatically improve patient problems. If patients have a significant amount of protein, mucous, and lipid deposits, it is critical to ask them to explain in detail how they are caring for their lenses. First, ask patients what they do right after removing the lenses. They may be just placing their lenses in fresh solution, rather than manually rubbing the lenses prior to storing. Some patients require additional physical manipulation of the lens to ensure removal of stubborn deposits. If deposits are viewed on the posterior side of the scleral lens, patients may not be rubbing the inside of their scleral lens well enough. Many times, this includes patients who have long/false fingernails or patients who have very large hands and fingers. For these patients, using a tool such as a cotton-tipped swab to rub the inside of the bowl can be helpful to remove inner deposits.
Also ask patients about which care system they are using and how the care system is being used. Surprisingly, many patients will list the steps of their care regimen incorrectly, and simply adjusting their care regimen can solve the issue. When patients have stubborn deposits, practitioners should consider a multi-step care system or a hydrogen peroxide system rather than a multipurpose solution. Sometimes patients require additional steps to maintain cleaner lenses. If a patient is suffering from deposits, try switching the patient to a different care system to see whether that solves the problem.
Not all materials work for every patient. Although limited, there are a variety of hyper-Dk materials that are used in scleral lens manufacturing. Some patients’ ocular surfaces respond better to a different scleral lens material. If altering the care system does not effectively solve this problem, consider changing the scleral lens material and then observe your findings. Coating the lens with a surface treatment can also help decrease deposits and improve wettability. Consider adding a surface coating to assist with deposit resistance. Keep in mind that patients must properly care for their coated lenses with certain care systems and that they must avoid alcohol-based solutions and extra-strength cleaners, as these may strip off the coating.
A final vision issue is perhaps the most difficult challenge of all: post-lens tear layer (PLTL) fogging can be extremely frustrating for both patients and practitioners. The source of the debris in the PLTL is unclear, or it varies among patients. Basic recommendations can include switching to a higher-viscosity, preservative-free solution, which can help reduce the influx of debris behind the lens. Another tip is to use sodium fluorescein over the scleral lens and observe the areas under the lens’ landing zone that allow the fluorescein to enter the PLTL. These channels are created by a loose edge, and the lens should be adjusted to tighten those edges to create a better seal, if possible. Other research has shown that scleral lenses that have excessive clearance can lead to PLTL fogging.1,2 Altering the central clearance may help to decrease the amount of PLTL fogging. Sometimes adding a more hydrophilic coating to the lens surface can improve wettability and deposit resistance as well.
Scleral lenses can be the most comfortable contact lenses that a patient has ever worn. This is especially true in cases of significant ectasia, advanced ocular surface disease, and graft-versus-host disease. Their unique fitting characteristics that result in no corneal touch and a post-lens tear reservoir that bathes the cornea for an extended period of time bring much needed relief to many patients. However, there are circumstances in which this may not always be the case.
All lenses sink into the spongy conjunctiva with wear. The amount of settling varies from person to person based on their physiology and the attributes of the lens worn. Clinicians are naturally focused on central clearance, but they must remain mindful of limbal clearance as well as the haptic edge. Over the first few weeks of wear, lenses may burrow down into the conjunctiva, causing hyperemia and a burning or “hot” sensation. Patients may complain of a visible indentation ring after removal. This “tight lens syndrome” may also be exacerbated by an aggressive application technique that pushes the lens onto the eye. It is a good idea to have patients demonstrate their application technique, either to the practitioner or to one of the staff, at the follow-up visit to ensure proper technique. If the lens is determined to be excessively tight, remedies may include flattening the haptic, specifying a toric haptic, or increasing the overall diameter (OAD).
Conversely, lenses that are too flat in the landing zone will create edge awareness. This may be due to lid interaction with the blink as well as to lens movement. Scleral lenses should move very little if at all. Excessive edge lift can often be visualized by angling the optic section beam of the slit lamp across the edge from the middle of the lens outward so that a shadow is cast. Lissamine green dye may also be applied to the superior bulbar conjunctiva. The dye will be drawn up under the areas of the haptic where clearance is excessive. This is easily viewed with white light.
A spherical lens fit on a toric or irregular sclera may cause areas of blanching where the lens edge is compressing the blood vessels. This can be managed by using toric peripheral curves or quadrant-specific edges (Figure 3) when appropriate.
Lenses should be removed at each progress visit so that corneal health may be assessed. Excessive staining of the cornea may be the result of corneal touch, especially in patients who have corneal grafts, a very elevated central cone, or the extremely irregular topography of a post-radial keratotomy cornea. The latter can be one of the most challenging and frustrating cases. Areas of touch will be well-defined with sodium fluorescein stain. Remedies include increasing the sagittal depth of the lens and sometimes specifying different clearances in two principal meridians. Check with the laboratory to see whether this option is available in your scleral lens of choice.
Earlier scleral lens designs were generally larger (“full sclerals”) compared to those commonly used today.3 These lenses were often 20mm to 23mm in OAD. They had wide, flat haptics, and most were spherical. Scleral lens pioneer Dr. Ken Pullum from the United Kingdom likes to joke that we discovered the pinguecula with the use of “mini-scleral” lenses, for which the diameters are in the range of 14mm to 18mm. These may indeed be landing right where pingueculae are most elevated. The lens edge might dig into the side of the bump or land squarely on top, compressing the tissue. Patients may complain of awareness or even pain in that area. Tenderness may remain even upon lens removal.
Fortunately, most labs have a strategy to deal with these elevations. Notching, in which a section of the edge is removed to accommodate the “bump” (Figure 4) has been available for some time. Experienced practitioners may even perform in-office notching using a rotary tool. This may not always be the best choice because as the edge is carved away, lens thickness either increases or decreases depending on the lens power, and it can be difficult to duplicate in the case of lens loss or breakage. The lack of a uniform edge could also result in decreased comfort.
Many manufacturers feature lens edge configurations that are elevated over the lesion(s) and are incorporated into the manufacturing process (Figure 5). These features go by various names, but they are well-defined, consistent, and reproducible. Edge uniformity is maintained, which ensures a more comfortable lens. Patients who have previously worn a lens without this adjustment may remark that they do not feel the lens at all. Redness and discomfort over elevated areas is eliminated in a well-fit lens.
Lastly, an anterior segment optical coherence tomographer (OCT) is an excellent tool to evaluate the relationship of the lens edge to the ocular surface. It can reveal tight and loose edges as well as quantify the central and limbal clearance (Figure 6) to also assist in troubleshooting lens comfort.
LENS APPLICATION TIPS
Scleral lens handling is one of the primary reasons for patient dropout, so it is extremely important to review this in-depth with patients who are new to this modality. Some practitioners review handling at the very first visit, while others wait for the scleral lens dispense. There is no right or wrong way to approach lens training, but it is important to review this process in great detail.
Make sure to have patients try lens application with several different devices. Some patients do well with the traditional large plunger, while others do better with an o-ring or a scleral lens applicator (Figure 7). Notice that with the large plunger, patients will need to designate one hand to hold the plunger, while the other hand will control the eyelids (Figure 8). Sometimes this is not the best method for patients, especially those who require more lid control. Patients using an o-ring, dental ring, or a scleral lens applicator ring will only need to balance the scleral lens on one finger, which allows the other fingers to manipulate the lower eyelid. These application devices should be considered when patients require more control of their eyelids.
Some patients do not want to be reliant on any devices to apply their lenses. In this case, patients can balance the lens on two or three fingers like a tripod. The reason why most patients cannot balance their scleral lens on just one finger is because after filling the lens with non-preserved saline, the lens gets top heavy and falls over and off of the finger. Application devices are the most common way to help patients apply scleral lenses. For patients who have extreme difficulty with scleral lens application, a scleral lens stand should be considered (Figure 9). Scleral lens stands can be purchased, or patients can make a home-made version out of a styrofoam coffee cup (Figure 10). Either way, this option frees up both hands for patients to manipulate their eyelids more easily and with full control. A free educational video highlighting different ways to apply scleral lenses can be viewed on sclerallens.org, which is an excellent resource for new wearers.
To prevent application bubbles, it is best to overfill the bowl with nonpreserved saline. Underfilling the bowl can often lead to bubbles upon application, so teaching patients how much solution to add to the bowl is important. For patients who have extreme difficulty with spillage or problems with application errors, consider adding a more viscous preservative-free tear to the bowl of the lens to help prevent application bubbles. Adding a few drops of a more viscous solution prior to adding the nonpreserved saline can help patients who have problems with application errors.
SCLERAL LENS REMOVAL
Removing scleral lenses can be challenging to novice practitioners and to first-time scleral lens patients. Scleral lens removal should not be too difficult if the lens fits properly. If patients have extreme problems with removing their lens, it could be due to tight lens syndrome or to some other serious complication that would warrant lens reassessment.
Before removing scleral lenses, patients or practitioners can instill a drop or two of preservative-free artificial tears or saline into the eye. Then, with the eye closed, gently massage the eyelid around the edges of the lens to prepare it for removal. Next, wet the tip of a small plunger with GP solution or preservative-free artificial tears and gently apply the plunger to the inferior one-third of the scleral lens, making sure that the plunger makes full contact with the lens. This is an important step because if the plunger is half on the lens and half on the conjunctiva, the plunger will not attach to the scleral lens and thus will not be able to remove it. Pressing the plunger onto the lens with excessive force creates additional suction, making the lens more difficult to remove. Be sure to remind patients to never place the plunger directly on the center of a scleral lens and attempt to remove it, because this will just pull on the surface of the lens and eye, and patients will feel like they are pulling their eye out.
Once the tool is attached to the lower third of the lens, lift up and out to remove. Think of a trap-door motion with the hinge at the superior limbus. Sometimes adding a twisting motion can help to break the suction.
In-office tip for practitioner removal of a scleral lens: Place the plunger on the superior third of the lens. Pull the lens down and out in a hinging motion. This prevents the possibility of dragging the edge of the lens across the cornea.
If patients have difficulty removing their scleral lenses, it is important to obtain more information. Does lens removal become more difficult as wear time increases? Is there increased redness after wearing the lenses for an extended period of time? Is there a compression ring left on the conjunctiva after removal? Is there any pain toward the end of the day when wearing scleral lenses? Sometimes asking more questions can guide you in the right direction as to what the underlying problem might be. Also, observing how patients apply and remove their lenses can be very beneficial in their management.
With all of the scleral lens design options available today, it is a great time to be fitting scleral lenses. Many patients can be successfully fit with the standard fitting approaches. However, some patients will need extra troubleshooting. Identifying a patient issue as either a visual, comfort, or handling concern is a first step in improving the lens wearing experience. Hopefully, this article can help with resolving some of the most common scleral lens hurdles encountered in practice. CLS
- McKinney A, Miller W, Leach N, Polizzi C, van der Worp E, Bergmanson J. The cause of midday visual fogging in scleral gas permeable lens wearers. Invest Ophthalmol Vis Sci. 2013 Jun;54:5483.
- Walker MK, Bergmanson JP, Miller WL, Marsack JD, Johnson LA. Complications and fitting challenges associated with scleral contact lenses: A review. Cont Lens Anterior Eye. 2016 Apr;39:88-96.
- Jedlicka J. Scleral Lenses: Past and Present. Contact Lens Spectrum. 2016 Oct:31(Suppl: Scleral Lenses: Understanding Applications and Maximizing Success): 4,6,7.