For patients with keratoconus, corneal scarring, post-transplant irregularity, or secondary corneal ectasia, clearer vision is often not as simple as changing a pair of spectacles. When the corneal surface becomes irregular, conventional glasses or soft contact lenses may not fully correct distorted optics, leaving patients with blurred vision, reduced visual quality, and difficulty in daily activities.
Scleral lenses offer a different approach. Unlike conventional corneal contact lenses, scleral lenses vault over the cornea and rest on the conjunctival tissue overlying the sclera. The fluid reservoir between the lens and the cornea can help mask corneal irregularities and improve optical performance. Although scleral lenses have been widely studied in non-Asian populations, evidence in Chinese eyes remains limited, especially for patients with irregular corneas. Anatomical differences such as eyelid morphology, eyelid tension, and palpebral aperture size may influence lens fitting and wearing experience in Asian eyes.
A multicenter prospective clinical study published in Eye Discovery provides new evidence for this population. The study evaluated the short-term clinical outcomes of a four-zone scleral lens in Chinese adults with irregular corneas caused by primary or secondary corneal ectasia, corneal transplantation, or corneal scarring. The research was conducted across five independent clinical sites in China, with investigators from Rayzon Medical Technology Co., Ltd., Eye Hospital of Wenzhou Medical University, Sichuan University, Queensland University of Technology, and collaborating institutions.
The trial was designed as a prospective, interventional, open-label, single-arm study. A total of 144 participants were screened, 138 entered the study, and 131 completed the three-month follow-up. In total, data from 201 eyes were analyzed, including 176 eyes with keratoconus, 20 eyes with non-keratoconus ectasia, and several eyes with corneal injury, herpes simplex keratitis, or lattice corneal dystrophy. Participants attended visits at baseline, lens dispensing, one week, one month, and three months. Comprehensive ophthalmic examinations were performed at baseline and at three months, including visual acuity testing, anterior segment assessment, corneal topography, endothelial cell density measurement, intraocular pressure measurement, and fundus examination.
The main finding was a high rate of short-term visual rehabilitation. After one month of scleral lens wear, 128 of the 131 participants who completed the study achieved an improvement of at least 0.20 logMAR in best corrected visual acuity, corresponding to a success rate of 97.7%. At the eye level, 198 of 201 eyes achieved this level of improvement. The median improvement in best corrected visual acuity was 0.30 logMAR, with greater improvements observed in eyes with more advanced baseline visual impairment.
The study also reported encouraging fitting efficiency. The four-zone scleral lens used in the study allowed customization of multiple parameters, including diameter, sagittal depth, landing angle, and back-surface toricity. On average, 1.5 lenses per eye were required to finalize the lens fit over the three-month period. For clinical practice, this suggests that, when supported by trained practitioners and a standardized fitting protocol, empirical fitting with this lens design may be feasible with a relatively small number of ordered lenses.
Most participants who completed the study maintained regular lens wear. At the three-month visit, 72.5% of participants wore the lenses for at least eight hours per day, and 83.9% wore them for at least five days per week. Approximately 90% of eyes received high comfort ratings, meaning that participants either noticed the lenses only occasionally or could not feel them at all. Around 90% of eyes were also rated as having vision that was rarely or never blurred during scleral lens wear.
Short-term ocular safety findings were also generally favorable. No significant adverse events were reported during the three-month lens wear period. No new corneal neovascularization, corneal infiltrates, or corneal infections were observed. Some eyes developed grade 2 corneal staining, limbal redness, conjunctival indentation, or persistent bulbar redness, but these issues were managed through lens refitting, reduced wearing time, or additional training in lens application and removal. Corneal endothelial cell density, intraocular pressure, and most ocular parameters showed no clinically meaningful adverse changes over the three-month follow-up.
However, the findings should be interpreted within the study's limits. This was a single-arm trial without a control group using other forms of correction, such as corneal rigid gas-permeable lenses, piggyback lenses, or spectacles. Therefore, the study cannot determine whether the four-zone scleral lens is superior to other correction options. The follow-up period was also limited to three months, which supports short-term conclusions but does not establish long-term safety. Long-term monitoring remains important for scleral lens wearers, especially those with compromised corneas, because potential concerns include corneal hypoxia, corneal edema, endothelial cell changes, and corneal neovascularization. The authors noted that an extended one-year study is ongoing.
The study population was also selected according to specific inclusion and exclusion criteria. Participants were Chinese adults aged 18 to 65 years with irregular corneas and reduced best corrected visual acuity. Patients with active corneal infection or inflammation, contraindications to contact lens wear, recent orthokeratology lens wear, recent corneal cross-linking or corneal graft suture removal, or advanced keratoconus requiring surgery within the next three months were excluded. As a result, the findings should not be generalized to all patients with irregular corneas without clinical evaluation.
The study was initiated and funded by Rayzon Medical Technology Co., Ltd., and the authors disclosed that Qi Tan is a Clinical Research and Development Director at the company. This disclosure does not invalidate the findings, but it is important context for readers when interpreting a medical device study.
Overall, this multicenter prospective study adds clinically relevant evidence for scleral lens use in Chinese patients with irregular corneas. It suggests that a four-zone scleral lens can provide meaningful short-term visual improvement and good tolerance for many appropriately selected patients. Further studies with longer follow-up and comparative designs will help clarify the long-term safety profile and the position of scleral lenses within the broader visual rehabilitation pathway for irregular corneas.
DOI: 10.1016/j.edisc.2026.100043.
