In addition to the larger amount of trefoil, coma, tetrafoil, and secondary astigmatism, keratoconic eyes tend to have a reverse coma pattern and reverse trefoil aberrations compared with normal eyes. Although RGP lenses correct the irregular astigmatism, smaller comet-like retinal images in the opposite direction remain due to residual vertical coma.

Keratoconus is a bilateral and asymmetric disease which results in progressive thinning and steeping of the cornea leading to irregular astigmatism and decreased visual acuity. Traditionally, the condition has been described as a noninflammatory disease; however, more recently it has been associated with ocular inflammation. Keratoconus normally develops in the second and third decades of life and progresses until the fourth decade. The condition affects all ethnicities and both sexes. The prevalence and incidence rates of keratoconus have been estimated to be between 0.2 and 4,790 per 100,000 persons and 1.5 and 25 cases per 100,000 persons/year, respectively, with highest rates typically occurring in 20-to 30-year-olds and Middle Eastern and Asian ethnicities. Progressive stromal thinning, rupture of the anterior limiting membrane, and subsequent ectasia of the central/paracentral cornea are the most commonly observed histopathological findings. A family history of keratoconus, eye rubbing, eczema, asthma, and allergy are risk factors for developing keratoconus. Detecting keratoconus in its earliest stages remains a challenge. Corneal topography is the primary diagnostic tool for keratoconus detection. In incipient cases, however, the use of a single parameter to diagnose keratoconus is insufficient, and in addition to corneal topography, corneal pachymetry and higher order aberration data are now commonly used. Keratoconus severity and progression may be classified based on morphological features and disease evolution, ocular signs, and index-based systems. Keratoconus treatment varies depending on disease severity and progression. Mild cases are typically treated with spectacles, moderate cases with contact lenses, while severe cases that cannot be managed with scleral contact lenses may require corneal surgery. Mild to moderate cases of progressive keratoconus may also be treated surgically, most commonly with corneal crosslinking. This article provides an updated review on the definition, epidemiology, histopathology, aetiology and pathogenesis, clinical features, detection, classification, and management and treatment strategies for keratoconus.

PurposeTo investigate the effect of low-addition soft contact lenses (CLs) with decentered optical design on the progression of myopia in children in a pilot study.Subjects and methodsTwenty-four Japanese children age 10–16 years with baseline myopia of −0.75 to −3.50 D sphere and ≤1.00 D cylinder were studied. The new CLs were designed to have a nasal decentration with the optical center centered on the line of sight, and with progressive-addition power of +0.5 D peripherally. Monofocal soft CLs were used as controls. A pair of new CLs or control CLs was randomly assigned to the children, and they wore the lenses for 12 months during the first phase. Then, the type of CLs was changed, ie, a crossover design, and the children were observed for another 12 months during the second phase. The end points were changes in axial length and refractive error (spherical equivalent) under cycloplegia.ResultsThe change of axial length in the new-CL and control-CL groups was not different between 12 months and baseline, the change of axial length between 12 months and 1 month in the new-CL group (0.09±0.08 mm) was significantly smaller (47%) than that in the control-CL group (0.17±0.08 mm, P<0.05). During the same period, the change of refractive error in the new-CL group was not significantly different from that in the control group. Neither the change in axial length nor refractive error in the new-CL group was significantly different from those in the control-CL group in the second phase.ConclusionThis pilot study suggests that low-addition soft CLs with decentered optical design can reduce the degree of axial elongation in myopic children after an initial transient phase of CL wear. The reduction of the progression of myopia by low-addition soft CLs warrants further investigations.

Although PMCD and KC are categorized as noninflammatory corneal thinning disorders, the HOA patterns in the 2 groups differed, possibly due to differences in the positions of the corneal apex. PMCD and KC may cause distinctively different deterioration in the quality of vision.

Citation: Suzaki A, Maeda N, Fuchihata M, Koh S, Nishida K, Fujikado T. Visual performance and optical quality of standardized asymmetric soft contact lenses in patients with keratoconus. Invest Ophthalmol Vis Sci. 2017;58:289958: -290558: . DOI:10.1167 PURPOSE. To evaluate the visual performance and optical quality of a standardized asymmetric soft contact lens (SCL) used for correction of higher-order aberrations (HOAs) in eyes with keratoconus. METHODS.We included 30 eyes (26 patients) with keratoconus (average K: 45.7 6 2.3 diopters [D]). The patients were subjected to corneal tomography, aberrometry, measurements of manifest refraction and visual acuity (VA), and visual analog scale (VAS) assessments. The study lenses were made using a molding method and consisted of six standardized types, in which an asymmetric power distribution of approximately 2 to 12 D (2-D step) was used to correct HOAs. The lens type suitable for each eye was selected based on the corneal tomography and aberrometry data. The on-eye performance of the lens was evaluated using aberrometry (4-mm pupil), over refraction, VA, and VAS.RESULTS. The standardized asymmetric SCL improved the best spectacle-corrected VA from À0.07 6 0.09 to À0.11 6 0.08 logMAR (P < 0.05) and the mean VAS score from 66.2 6 21.8 to 75.4 6 20.5 (P < 0.05). Vertical coma decreased significantly (À0.50 6 0.36 lm without SCL; À0.36 6 0.34 lm with SCL; P < 0.01). In subgroup analysis, subjects in the high VAS group (score ‡ 75) accounted for 70% of all subjects, and this was the group in which the vertical coma decreased significantly from the level without the lens. CONCLUSIONS.A standardized asymmetric SCL can reduce HOAs and improve vision quality when compared with spectacles in patients with keratoconus who wear rigid gas-permeable lenses.

Short-term and long-term OK lens wear induces significant changes in corneal aberrations that are not significantly correlated with changes in axial elongation after 2-years.

Background:The aim was to assess the potential association between entrance pupil location relative to the coaxially sighted corneal light reflex (CSCLR) and the progression of myopia in children fitted with orthokeratology (OK) contact lenses. Additionally, whether coma aberration induced by decentration of the entrance pupil centre relative to the CSCLR, as well as following OK treatment, is correlated with the progression of myopia, was also investigated. Methods: Twenty-nine subjects aged six to 12 years and with myopia of -0.75 to -4.00 DS and astigmatism up to 1.00 DC were fitted with OK contact lenses. Measurements of axial length and corneal topography were taken at six-month intervals over a two-year period. Additionally, baseline and three-month topographic outputs were taken as representative of the pre-and post-orthokeratology treatment status. Pupil centration relative to the CSCLR and magnitude of associated corneal coma were derived from corneal topographic data at baseline and after three months of lens wear. Results: The centre of the entrance pupil was located superio-temporally to the CSCLR both pre-(0.09 ± 0.14 and -0.10 ± 0.15 mm, respectively) and post-orthokeratology (0.12 ± 0.18 and -0.09 ± 0.15 mm, respectively) (p > 0.05). Entrance pupil location pre-and post-orthokeratology lens wear was not significantly associated with the two-year change in axial length (p > 0.05). Significantly greater coma was found at the entrance pupil centre compared with CSCLR both pre-and post-orthokeratology lens wear (both p < 0.05). A significant increase in vertical coma was found with OK lens wear compared to baseline (p < 0.001) but total root mean square (RMS) coma was not associated with the change in axial length (all p > 0.05). Conclusion: Entrance pupil location relative to the CSCLR was not significantly affected by either OK lens wear or an increase in axial length. Greater magnitude coma aberrations found at the entrance pupil centre in comparison to the CSCLR might be attributed to centration of orthokeratological treatments at the CSCLR.

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