Navigating the world of scleral lenses?
Start with our expert tips on achieving the perfect fit.
Scleral lenses are large diameter, rigid gas-permeable lens that vault over cornea and exclusively rests on the sclera, maintaining a tear fluid between posterior surface of lens and anterior surface of cornea. Scleral lenses provide constant hydration to ocular surface and provide clear vision along with extreme comfort to its user. [1]
FITTING GUIDE
No standardized fitting guidelines have been established for scleral lenses.
Medlens Innovations suggests using an initial diagnostic lens with a base curve approximately 1 diopter steeper than the steepest corneal curve and diameter based on palpebral fissure size/globe size/corneal clearance.
In scleral lens fitting, achieving the correct sagittal depth is crucial, prioritizing it over aligning with the central cornea, which differs from fitting corneal lenses.
Scleral Radius Interpretation: CL edge should rest above the conjunctiva.
Fitting goals include aligning the sclera with minimal or no blanching of conjunctival vessels and ensuring complete limbal and corneal clearance.
All pressure, weight and bearing of lens should be on the sclera, not on cornea. If initial lenses do not clear the cornea, subsequent lenses with greater sagittal depth are used until clearance is achieved.
Conversely, lenses with excessive post-lens fluid reservoir depth are exchanged for shallower ones until optimal clearance (0.15 to 0.4 mm) is attained, determined by comparing reservoir thickness to corneal thickness. Once appropriate sagittal depth is established, over-refraction is conducted. [2]
Practitioners believe that 200 & 400 µm is the appropriate apical clearance at initial CL application. Given that a settled clearance of around 200 µm is desired, an initial figure of around 400 µm is probably more appropriate.
When to consider SCLERAL LENSES - When the difference in corneal height (along any given meridian) is > 400 µm.
PATIENT EDUCATION
Cleaning hands thoroughly with a mild soap before lens insertion or removal.
Proper cleaning of lens with cleaning agent/solution to prevent corneal toxicity or infection. Before insertion, patient must fill the lens with saline to avoid air bubble in it.
With help of a plunger, patient may stabilize the lens, fill with saline and thus put it inside the eye.
There is another alternative to plunger insertion of lens, which is 3-finger method where you use thumb, index and middle finger to create a tripod stand for lens then put the lens over it and fill it with saline and insert the lens into the eye.
The patient should always re-check their eye to look for any air bubble trapped inside the lens as it can cause discomfort, decrease vision, etc.
Scleral lenses or any lenses should be cleaned and stored with a good multi-purpose cleaning solution (MPS).
Patient should clean the lenses by rubbing it thoroughly for about 10-15 seconds and soak the lenses in the lens case with that solution.
Lenses must be cleaned prior to wear and after removal of lens also the patient should clean it and soak the lenses in case with fresh solution.
If the patient is not wearing the lenses, it’s advised to change the lens solution of the lens case everyday to avoid contamination of lenses.
Also, it’s advised to get the lenses cleaned with 3% hydrogen peroxide or chlorhexidine solutions twice a month to avoid contamination of lenses.
It’s advised not to use any eye drops over the scleral lenses and ideally, one should not sleep or bathe or swim with the lenses on.
DO’S and DON’T’s in CONTACT LENS
Reference:
1. Schornack MM. Scleral lenses: a literature review. Eye Contact Lens. 2015 Jan;41(1):3-11. doi: 10.1097/ICL.0000000000000083. PMID: 25536528.
2. Schornack MM, Pyle J, Patel SV. Scleral lenses in the management of ocular surface disease. Ophthalmology. 2014 Jul;121(7):1398-405. doi: 10.1016/j.ophtha.2014.01.028. Epub 2014 Mar 14. PMID: 24630687.
3. Ruiz-Lozano RE, Gomez-Elizondo DE, Colorado-Zavala MF, Loya-Garcia D, Rodriguez-Garcia A. Update on indications, complica tions, and outcomes of scleral contact lenses. Med Hypothesis Discov Innov Ophthalmol. 2021 Winter; 10(4): 165-178.
5. International Association of Contact Lens Educators (IACLE) modules.
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