In new research published in Contact Lens & Anterior Eye, investigators conducted a cross-sectional study to examine how silicone hydrogel contact lenses (SH-CL) affect the meibomian glands, corneal structure, and ocular surface parameters.
Give me some background first.
There are an estimated 140 million contact lens (CL) wearers worldwide, a majority of which are soft CL wearers.
Discomfort symptoms affect 30% to 50% of CL wearers and are the leading cause of CL wear discontinuation.
Further, CL wear can cause changes in the ocular environment, and cause ocular discomfort symptoms such as:
- Dryness
- Irritation
- Fatigue
Now, talk about the study.
In this study, investigators recruited 100 participants and conducted the following:
- Routine ophthalmic examination
- Had participants fill out the Ocular Surface Disease Index (OSDI) questionnaire
- Ocular surface and tear film examination
- Meibography and in vivo confocal microscopy (IVCM) measurements
- Corneal sensitivity measurement
Who was included in the study?
A total of 50 patients with a mean age of 25.8 years who had worn SH-CL for at least six months daily for at least eight hours a day and with a monthly replacement scheme.
The control group was comprised of 50 age and sex-matched individuals with a mean age of 25.9 years.
Participants were excluded from the study if:
- They were on topical medication
- Had a history of ocular surface surgery or trauma
- Had a spherical equivalent (SE) refractive error of more than 6.00 DS or + 6.00 DS
Note: No participants had any systemic disease or were taking any systemic medications that could impact the ocular surface.
Findings?
Compared to control participants, SH-CL wearers had:
- Significantly lower endothelial cell density (P = 0.01)
- Significantly higher polymegethism rate (P < 0.001)
- Shorter tear break-up time (TBUT) (P = 0.01)
- Higher corneal fluorescein staining (P = .04)
- Was associated with longer visual display terminal (VDT) work duration (P = .05)
- Higher OSDI scores (P < .001)
Go on …
There was a significant difference in the meiboscores of participants (P < .001). The scores were:
- 2.64 ± 1.08 (1-5) for the CL group
- 1.22 ± 0.95 (0-4) for the control group
While not statistically significant, the biomicroscopic evaluation showed meibomian gland dysfunction (MGD) in:
- 34% of the CL group
- 20% of the control group
There was no significant difference in corneal sensitivity.
Limitations?
The authors noted the small sample size.
Expert opinion?
The investigators stated that, while SH-CLs are more ocular-compatible than other types of lenses, “they still cause alterations in the ocular surface, meibomian glands, corneal structure, and tear film.”
Additionally, they express that their research could contribute to future studies regarding CL-wear effects on the ocular surface and possible mechanisms of CL-related ocular discomfort.
Take home.
These findings show that SH-CL wear can lead to increased dry eye symptoms and ocular discomfort, especially in longer VDT work duration.