The influence of large-diameter multifocal contact lens on ocular surface, visual quality, and visual function for presbyopic adults with dry eye syndromes.

This study investigated the influence of large-diameter multifocal contact lenses on the ocular surface, visual quality, and visual function for presbyopic adults with dry eye syndromes. The study enrolled 40-55-year-old adults with presbyopia and dry eye syndromes (DES). The subjects were randomly assigned to three groups wearing different designs of contact lenses (Proclear, SMR, and Optimum) for 6-8 h a day for two weeks. Ocular surface health, tear quality, visual quality, and visual function were measured before and after lens wear. No significant difference was observed across all three groups for the amount of conjunctival redness, blink frequency (lens on), and stereopsis vision before and after wearing. Although there seemed to be a significant declining trend for corneal staining and limbal redness, non-invasive tear break-up time (TBUT), and lipid layer thickness while lens wear, the measured values were all within the normal range. Vice-versa after lens removal, results also showed significant improvement on lipid layer thickness, blink frequency (lens off), and contact TBUT. A significant improvement was observed in the modulation transfer function (MTF) of the total area ratio after wearing contact lenses. In contrast, the MTF of the high-order aberration area ratio resulting from lens wear was lower than that of the baseline measurement. There are also significant improvements observed for SMR and Optimum regarding near visual acuity, near point of accommodation, and the subjective questionnaire (OSDI and VBP) scores. Although it is difficult to avoid a specific negative impact on the ocular surface and tear film, visual function and visual quality can still be positively improved, especially shown on larger diameter and distance-center designed multifocal contact lenses.

The influence of contact lenses with different optical designs on the binocular vision and visual behavior of young adults.

Theoretically, contact lenses change the accommodation and vergence demands of the eyes and directly or indirectly influence binocular vision. The purpose of this study was to investigate the influence of different optical designs of contact lenses on binocular vision and visual behavior among young adults. In this randomized, single-blinded experimental study, visual behavioral performance (VBP) and Ocular Surface Disease Index questionnaires were used for preliminary screening. Nineteen myopic subjects aged 20-26 years (21.59 ± 1.40 years) participated in the study. Baseline values for subjective refraction and binocular visual functions were evaluated. All the subjects were randomly grouped to wear different optical designs of single-vision, progressive, and bifocal contact lenses. Eye examinations were performed on the first day (CL baseline), 2nd week, and 4th week of wearing the lenses. In addition, subjects completed the VBP and visual quality questionnaire again at the end of the examination. Single-vision contact lenses (Lens 1) increased accommodative lag, negative relative accommodation, and distant and near vergence; however, vergence facilities, accommodative facilities, heterophoria, and the comfort and posture balance dimensions in the VBP questionnaire were improved. Progressive contact lenses (Lens 2) reduced the lag of accommodation and near vergence; in addition, vergence facilities and accommodative facilities were also improved. Bifocal contact lenses (Lens 3) affected negative and positive relative accommodation, but vergence facilities and accommodative facilities also progressed. Furthermore, both progressive (Lens 2) and bifocal (Lens 3) contact lenses enhanced overall visual behavioral performance. In terms of visual quality, single-vision contact lenses (Lens 1) were the most comfortable, progressive and bifocal contact lenses reduced distant visual acuity and stability, progressive contact lenses (Lens 2) had more complaints about halos at night, and bifocal contact lens (Lens 3) users were more likely to have double vision. Compared with single-vision contact lenses, progressive and bifocal contact lenses relaxed accommodation, reduced the lag of accommodation, and improved visual behavioral performance. Although the vergence function showed a significant change, it did not show worse trends when wearing contact lenses. Contact lenses with different optical designs have a great influence on binocular vision and visual behavioral performance.

Managing keratoconus with reverse-geometry and dual-geometry contact lenses: a case report.

PURPOSE: To present a case of keratoconus successfully managed with various rigid gas-permeable contact lenses with reverse-geometry and dual-geometry designs. METHODS: Case report. RESULTS: The steepest topographic keratometric readings of a 30-year-old woman with keratoconus were 62.18 diopters in the right eye and 54.70 diopters in the left eye. A conventional reverse-geometry lens worked well in the left eye. The more distorted right eye was fitted with a series of different reverse-geometry and dual-geometry lenses. Her visual acuity was 20/20 in each eye when she wore contact lenses during the day. Unaided vision was as good as 20/25+ in the right eye and 20/20 in the left eye for several hours after lens removal. No significant complication occurred during 42 months of follow-up. CONCLUSIONS: Keratoconus is a corneal disease characterized by progressive stromal thinning and ectasia, typically in the inferior cornea. Rigid gas-permeable contact lenses are the most common management option to improve vision. Corneal surgery, such as keratoplasty, is the next choice when contact lenses are ineffective or intolerable. The large overall diameter and contact area of reverse-geometry and dual-geometry lenses can assist in stabilizing the lenses on distorted corneas. These contact lenses may provide viable alternatives for management before corneal surgery.