Change in Tear Layer Thickness under Scleral Contact Lenses in Keratoconus Patients and Normal Cornea Volunteers

Atiporn Thuangtong; Nuttacha  Taetrongchit; Rung  Kemahayung

doi:10.33192/smj.v76i10.267608

Authors

Atiporn Thuangtong Department of Ophthalmology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
Nuttacha Taetrongchit Department of Ophthalmology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
Rung Kemahayung Department of Ophthalmology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand

DOI:

https://doi.org/10.33192/smj.v76i10.267608

Keywords:

Keratoconus, Scleral contact lenses, Post-lens tear layer thickness, Anterior Segment OCT

Abstract

Objective: To quantify rate of post-lens tear thickness change under scleral contact lenses in keratoconus patients and normal cornea volunteers.

Materials and Methods: We conducted a prospective observational study where semi-scleral lenses were fitted to 20 eyes (5 subjects, 10 eyes in each group). After insertion, post-lens tear thickness was measured at 0, 30 minutes and every hour up to 6 hours using Anterior Segment OCT. To analyze post-lens tear thickness and its rate of change at each time point, both within and between groups, a linear mixed model was used.

Results: The initial mean post-lens tear thickness (µm) was 742 ± 50 and 440 ± 50 in keratoconus and normal cornea group, respectively. The mean rate of change (µm/hr) was highest in the first 30 minutes in both groups (80.8 ± 8.7, 132.2 ± 8.8 in keratoconus and normal cornea group). Following the first four hours in keratoconus and the first hour in normal cornea group, the reduction rate in post-lens tear thickness exhibited no statistically significant difference from the rate of change observed during the 5-6 hour period. The mean percentage of total change over 6 hours after lens insertion was higher in normal cornea compared to keratoconus group (36.6% vs 22.5%).

Conclusion: The reduction in post-lens tear thickness follows a nonlinear pattern. The mean rate of change was highest after insertion and remained stable after four hours in keratoconus and one hour in normal cornea group. The percent change over the 6-hour period was greater in normal cornea group.

References

Romero-Jiménez M, Santodomingo-Rubido J, Flores-Rodríguez P, González-Méijome J-M. Short-term corneal changes with gas-permeable contact lens wear in keratoconus subjects: A comparison of two fitting approaches. J Optom. 2015;8(1):48-55.

Jacobs DS. Update on scleral lenses. Curr Opin Ophthalmol. 2008;19(4):298-301.

Gould HL. Therapeutic effect of flush fitting scleral lenses and hydrogel bandage lenses. Int Surg. 1973;58(7):469-72.

Rathi VM, Mandathara PS, Dumpati S, Sangwan VS. Change in vault during scleral lens trials assessed with anterior segment optical coherence tomography. Cont Lens Anterior Eye. 2017;40(3):157-61.

Segal O, Barkana Y, Hourovitz D, Behrman S, Kamun Y, Avni I, et al. Scleral contact lenses may help where other modalities fail. Cornea. 2003;22(4):308-10.

Michaud L, van der Worp E, Brazeau D, Warde R, Giasson CJ. Predicting estimates of oxygen transmissibility for scleral lenses. Cont Lens Anterior Eye. 2012;35(6):266-71.

Esen F, Toker E. Influence of Apical Clearance on Mini-Scleral Lens Settling, Clinical Performance, and Corneal Thickness Changes. Eye Contact Lens. 2017;43(4):230-5.

Otchere H, Jones LW, Sorbara L. Effect of Time on Scleral Lens Settling and Change in Corneal Clearance. Optom Vis Sci. 2017;94(9):908-13.

Schornack MM, Patel SV. Relationship between corneal topographic indices and scleral lens base curve. Eye Contact Lens. 2010;36(6):330-3.

Caroline PJ. Scleral Lens Settling. Contact Lens Spectrum. 2012;27:56.

Kauffman MJ, Gilmartin CA, Bennett ES, Bassi CJ. A comparison of the short-term settling of three scleral lens designs. Optom Vis Sci. 2014;91(12):1462-6.