Evaluation of Corneal Alterations After Short-Term Silicone Hydrogel Contact Lens Use by Confocal Microscopy

Objectives: To evaluate the corneal subbasal nerve morphology, corneal sensitivity, and anterior segment alterations in short-term silicone hydrogel contact lens (SiHCL) users by confocal microscopy.Materials and Methods: The study included 25 right eyes of 25 male volunteers aged 25-30 years who had never used SiHCLs before. ocular surface disease index (OSDI), tear break-up time, Schirmer test, tear meniscus area, strip meniscometry tube, corneal sensitivity, and corneal subbasal nerve morphology were evaluated before and after 1 month of CL use.Results: OSDI was 10.6 +/- 1.1 before CL use and 17.2 +/- 1.2 after 1 month of CL use (p<0.01). Schirmer test distance was 16.3 +/- 2.3 mm before and 14.3 +/- 1.9 mm after 1 month of CL use (p>0.05). Tear film break-up time was 7.1 +/- 0.4 s before and 6.2 +/- 0.3 s after CL use (p>0.05). The tear meniscus area was 0.026 +/- 0.002 mm(2) before and 0.024 +/- 0.001 mm(2) after 1 month of CL use (p>0.05). Strip meniscometry tube results were 5.4 +/- 0.9 mm before and 4.9 +/- 0.8 mm after 1 month of CL use (p>0.05). Corneal sensitivity values were 3.2 +/- 0.4 mm before and 2.95 +/- 0.3 mm after 1 month of CL use (p>0.05). Dendritic cell density evaluated by confocal microscopy was 14.84 +/- 3.1 cells/mm(2) before and 32.57 +/- 4.2 cells/mm(2) after 1 month of CL use (p<0.01). Subbasal nerve tortuosity was 0.92 +/- 0.2 before and 1.03 +/- 0.2 after 1 month of CL use (p>0.05). Subbasal nerve density was measured as 4726 +/- 310 pixels/frame before and 4570 +/- 272 pixels/frame after 1 month of CL use (p>0.05).Conclusion: After a month of SiHCL use, no significant changes were observed in tear secretion, corneal sensitivity, tear meniscus volume, subbasal corneal nerve density, reflectivity, or tortuosity, while a significant increase was found in OSDI and dendritic cell density.