Artificial tears can alter keratometry measurements in dry eyes patients
In a recent development, researchers have highlighted that Tear film - stabilizing eye drops prior to keratometry measurements influenced K-readings significantly, especially in dry eyes. The team further said that a time period of more than 5 minutes should be allowed to pass after instillation of eye drops. The higher the viscosity of the eye drops, the stronger the influence and the longer its persistence. The findings have been published in American Journal Of Ophthalmology.
The developments of advanced-technology intraocular lenses (IOLs) and new measuring devices have heightened expectations of visual outcome after cataract surgery. Dry-eye disease is multifactorial and causes an unstable tear film with an irregular surface. Symptoms include a burning sensation and blurred vision, and biomicroscopic signs like shortened tear breakup time, corneal and conjunctival fluorescein staining, and lid-parallel conjunctival folds. Artificial tears are often used to ameliorate the ocular surface for obtaining a precise measurement of the eye. However, there are anecdotal reports that usage of eye drops can alter the measurement.
With this in view, researchers undertook the study to assess the influence of artificial tears of different viscosity on K-readings prior to cataract surgery.
The study was designed as a Prospective randomized crossover, before-and-after clinical study.A total of 123 eyes of 80 patients prior to cataract surgery were assigned to 2 groups based on normal and dry eyes. Two native baseline keratometries were followed by instillation of either high- or low-viscosity eye drops. Keratometry was repeated 30 seconds, 2 minutes, and 5 minutes after instillation. Influence of eye drops of different viscosity in normal and dry eyes on short time K-readings.
Data analysis revealed the following facts.
· Repeatability between native baseline measurements was high (standard deviation = 0.02 mm in normal and in dry eyes).
· In normal and dry eyes, a statistically significant increase in measurement variability after instillation of both low-viscosity and high-viscosity eye drops was observed (P < .01).
· Measurement variability was most pronounced between baseline measurement and 30 seconds and diminished over time.
· Variability of K-readings appeared higher in dry eyes compared with normal eyes.
· Astigmatism changed more than 0.5 diopters in 13.2% of normal eyes and 34.4% in dry eyes using eye drops of high viscosity.
For the full article follow the link: https://doi.org/10.1016/j.ajo.2020.08.024