Study of Myopia Correction Using Nanoporous Polymer Gas Permeable Contact Lenses

Ophthalmic treatments using contact lenses are now used by more and more specialists around the world. Improving contact lens (CL) materials is a condition that is constantly evolving. Contact lens materials are usually composed of polymer hydrogel or silicone hydrogel. The materials used for night contact lenses are gas permeable and they gradual flatten the center of the cornea which decreases the progression of myopia or myopic astigmatism. The aim of this study is to identify, in correlation with the chemical interactions between structural components of contact lenses and their biocompatibility with the surface layer and microtopography of the cornea or sclera, different incidents that occur in patients who have used rigid gas permeable contact lenses. The study was performed on a group of 10 patients who had a follow-up period between 4 and 6 years, who presented regularly for eye examinations. The following clinical parameters were analyzed: ocular refraction before and after wearing night contact lenses, types of contact lens materials, appearance of corneal topography, biomicroscopic examination of the anterior segment of the eye, keratometry, ocular comfort, as well as other incidents regarding this type of lenses. Difficulties caused by wearing contact lenses at night arose due to poor hygiene and maintenance in two cases or due to interruption of lens wear in one case.

Evaluation of Pollen Adhesion to Verofilcon-A Soft Contact Lenses

Purpose: A new 1-day disposable soft contact lens (SCL), verofilcon-A, constructed of silicone hydrogel material, has recently become available in Japan. This SCL has a very smooth surface produced by using the SMARTSURFACE ® Technology, and it was expected that pollen particles and protein components would not adhere easily to its surface. We examined the degree of pollen adhesion to the surface of the verofilcon-A material SCL and compared the results with those of other 1-day disposable SCLs (1DSCL). Methods: To determine the number of pollen grains attached to the surface of different types of SCLs, 0.01 mg/ml of cedar pollen solution was dropped onto the surface of 13 types of 1DSCL. After 24 h, each 1DSCL was rinsed in a shaker and washed five times with saline (n = 10 for each 1DSCL type). The number of pollen particles adhered to the 1DSCL and the percentage of surface area occupied by pollen was determined. Results: The number of pollen particles on the 1DSCLs ranged from 0 to 185 in the 200 × 200 µm area. The number of particles was lowest in the delefilcon-A and verofilcon-A SCLs with 0 particles, and the number was higher in the other 11 1DSCLs. The number of pollen particles was negatively correlated with the water content (r = −0.48), oxygen permeability (Dk; r = −0.43), oxygen transmissibility (r = −0.42), and center thickness (r = −0.33) of the 1DSCLs. The pollen adhesion area ranged from 0.0% to 3.1% and was lowest in the delefilcon-A and verofilcon-A 1DSCLs. There were significant differences in the pollen adhesion area between colored 1DSCLs (2.73 ± 1.97%) and clear 1DSCLs (1.03 ± 1.01%, P<0.001) and between hydroxyethyl methacrylate-based 1DSCLs (1.84 ± 1.45%) and silicone hydrogel-based 1DSCLs (0.05 ± 0.16%, P<0.001). Conclusion: These findings indicate that the verofilcon-A 1DSCL processed with SMARTSURFACE™ Technology is an excellent option for SCL users with allergic conjunctivitis during the high pollen season.

The effectiveness of hyperopia correction by wearing contact lenses in school-age children in the long-term follow-up

Background. Glasses and correction by wearing contact lenses are well tolerated by children with mild to moderate ametropia. In ametropia of high degree, an improvement of mo­nocular visual acuity with a contact lens compared to correction by glasses is 3.8 times higher. Materials and methods. The study included 56 children (112 eyes) aged 6 to 16 years with hypero­pic refraction and astigmatism, who used soft silicone hydrogel contact lenses to correct ametropia. In these patients, visual acui­ty, objective and subjective clinical refraction, axial length of the eye, corneal thickness and diameter, keratometry indicators were investigated, as well as phorometric data (accommodation, vergence, disparity areas of the oculomotor system and their inte­raction) in the early and late observation periods. Results. When using contact lenses for correction in school-age children with hyperopia and hyperopic astigmatism, after 3 years of observation there was a statistically significant increase in uncorrected visual acuity by 85 % (t = 7.9; p < 0.01), corrected visual acuity by 7 % (t = 7.4; p < 0.01), keratometry indicator in the weakest meridian by 1 % (t = 6.1; p < 0.01), in the strongest meridian by 1 % (t = 8.9; p < 0.01), central corneal thickness by 4 % (t = 4.6; p < 0.01), as well as a decrease in the spherical equivalent by 38 % (t = 3.1; p < 0.01), the amplitude of accommodation by 20 % (t = 5.8; p < 0.01), the negative relative accommodation by 20 % (t = 3.0; p < 0.01), the positive relative accommodation by 18 % (t = 3.5; p < 0.01), excessive accommodative response by 64 % (t = 7.2; p < 0.01), near phoria by 33 % (t = 4.4; p < 0.01), distance phoria by 22 % (t = 2.8; p < 0.01), the accommodation convergence to accommodation ratio by 18 % (t = 3.1; p < 0.01).

Incidence of Corneal Inflammation of Varying Severity among Contact Lens Wearers

The human cornea is an avascular, transparent tissue that permits or allows light rays to enter or reach the retina. The cornea is made up of several layers, each of which plays an important role in preserving the transparency and power of cornea. The epithelium, Bowmans layer, Descemet’s membrane and endothelium are the layers of the cornea. This study aimed to discover the incidences of severe and non-severe corneal inflammation amongst wearers of modern technology touch lenses. Studies on touch lens users providing with a corneal ulcer/infiltrates were reported. On the basis of severity, a medical severity matrix was utilized among cases of severe and non-severe corneal inflammation. There was a large distinction in severe corneal infection among ew-hydrogel and ew-silicone hydrogel. When it comes to evaluating touch lens-related corneal inflammation, a medical severity matrix is available in hand. Wearers of contact lenses who sleep with them have a appreciably low risk of severe corneal inflammation than those who simplest put on lenses for the duration of the day. Those cases who everyday sleep with lenses have a 5-fold lower risk of severe corneal inflammation as compared day-to-day hydrogel lenses for prolonged utilization.