Objective: To perform a comprehensive review of the current and historical scientific literature on fitting small scleral lenses (diameter <15 mm) and clarifying their advantages and disadvantages, in addition to their clinical applications.
Methods: The literature search was performed through PubMed from MEDLINE.
Results: Eleven studies of case series (258 eyes) were found. Indications were similar to those of larger scleral lenses, 74% for corneal irregularities (mainly keratoconus), whereas 26% for ocular surface diseases. In the studies on cases of irregular corneas, visual acuity improved significantly regarding the values before and after fitting the lenses (mean, 0.4-0.03 logMar, respectively). Moreover, no significant adverse effects on the ocular surface were reported, and most studies reported over 10 hr (or thereabouts) of daily wear without removing the lenses. A better corneal physiology and visual quality, easier fitting procedure and lens handling, and prolonged hours of wear are proposed as significant advantages over larger scleral lenses.
Conclusion: Small scleral lenses may be a safe and healthy alternative option to treat corneal irregularities and ocular surface diseases. These lenses can be fitted when it is necessary to improve visual quality and corneal physiology, when discomfort with other contact lenses is experienced, or when patients have difficulty handling larger diameters of scleral lenses. However, fitting these lenses is not suggested in severe cases or when it is not a reasonable clinical option.