As mentioned above, adults tend to be less tolerant or patient with sub-normal vision, particularly during the stabilization period, when undergoing ortho-k treatment. They reported that increasing the compression factor did not change ocular biometrics, the first fit success rate, or ocular health, but did correct refractive error more rapidly and change some higher-order aberrations, especially spherical aberration. investigated ortho-k lenses with different compression factors and compared effects of a conventional compression factor (0.75 D) and an increased compression factor of 1.75 D, ie extra compression factor of 1.00 D. noted that if the intention is to overcorrect by 0.75 D for daytime regression, a compression factor of 0.75 D is inadequate, and suggested that an additional 1.00 D of flattening power may be required. The compression factor (the Jessen factor) produces overcorrection (0.50 D to 0.75 D) to compensate daytime regression in ortho-k patients. The BC/BOZR is made flatter than flat K by the target Rx. The amount of myopia correction required, the target Rx, and the flat keratometry (flat K) reading by corneal topography identified in dioptric power are determined.
However, it is unclear how well accepted ortho-k can be for the adult population and what factors can contribute to successful lens wear as there are no reports available.Ĭurrently, for most ortho-k designs, the desired back optic zone radius (BOZR) calculation conforms to the Jessen formula. Based on clinical experience, compared with children, adults tend to be more demanding with respect to the quality of their vision. The use of an overnight lens-wearing protocol provides an ideal solution for those who do not wish, or are not permitted, to use vision correction aids in the daytime or at work, such as firemen.
When full reduction is achieved, after stabilization of treatment, users do not need to use another form of vision correction. In adults, ortho-k is used for myopia correction, rather than for myopia control, providing an alternative to refractive surgery for many patients. To date, most studies of ortho-k have focused on myopia control in children, and reports of ortho-k in adults have focused on comparing visual quality, aberrations, and binocular visual function with LASIK or soft contact lens, ,, ]. Modern orthokeratology (ortho-k), using reverse-geometry gas-permeable lenses, has the ability to temporarily reduce low to moderate myopia. The prevalence of myopia is continuing to rise in many countries, especially in Asia, where myopia has become the leading cause of blindness. Compared with baseline scores, 1-month NEI-RQL-42 subscales of dependence on correction, appearance, and satisfaction with correction significantly increased, and the glare score significantly decreased in both groups (all p < 0.05). Both groups recorded high scores in the level of satisfaction questionnaire, with no significant differences between groups ( p > 0.05). No significant differences in CRF and CH were found in the first month ( p > 0.05). The main complaint from participants was glare (both groups). However, the differences of corneal staining between the groups did not reach significance in any visit ( p > 0.05). Overall, the incidence of corneal staining was 77 % in the CCF and 79 % in ICF group central corneal staining was 15 % and 33 %, respectively. The first fit success rates were 90 % for CCF group and 83 % for the ICF group, SER reductions were 97 % and 95 % for the CCF and ICF group, respectively, with uncorrected high-contrast visual acuity of -0.06 (-0.18 to 0.42) and 0.00 (-0.16 to 0.52), respectively ( p > 0.05) at the 1-month visit.
Baseline data from 26 CCF and 24 ICF participants were analysed and no significant differences were observed between the two groups ( p > 0.05).