Discover the most talked about and latest scientific content & concepts.

Concept: Orthokeratology


There is increasing interest in fitting children with soft contact lenses. This review collates data from a range of studies to estimate the incidence of complications, specifically corneal infiltrative events and microbial keratitis, in patients under the age of 18 years.

Concepts: The Age, Cornea, Orthokeratology, Contact lens, Keratitis, Corneal ulcer, Bausch & Lomb


Prevalence of myopia is increasing worldwide. Outdoor activity is one of the most important environmental factors for myopia control. Here we show that violet light (VL, 360-400nm wavelength) suppresses myopia progression. First, we confirmed that VL suppressed the axial length (AL) elongation in the chick myopia model. Expression microarray analyses revealed that myopia suppressive gene EGR1 was upregulated by VL exposure. VL exposure induced significantly higher upregulation of EGR1 in chick chorioretinal tissues than blue light under the same conditions. Next, we conducted clinical research retrospectively to compare the AL elongation among myopic children who wore eyeglasses (VL blocked) and two types of contact lenses (partially VL blocked and VL transmitting). The data showed the VL transmitting contact lenses suppressed myopia progression most. These results suggest that VL is one of the important outdoor environmental factors for myopia control. Since VL is apt to be excluded from our modern society due to the excessive UV protection, VL exposure can be a preventive strategy against myopia progression.

Concepts: Ultraviolet, Light, Myopia, Lens, Orthokeratology, Contact lens, Corrective lens, Glasses


OBJECTIVE: Because of the northern location of Denmark, the length of the day over the year varies from 7 to 17.5 hours. Experimental and clinical results suggest that the development of myopia may be related to ambient light exposure. The purpose of current study was to investigate whether axial eye growth, myopia progression, or corneal power change in Danish myopic children varies with the length of the day. DESIGN: Cross-sectional study. PARTICIPANTS: Two hundred thirty-five children 8 to 14 years of age found to have myopia during screening for a clinical trial ( identifier, NCT00263471; accessed December 6, 2005). All children found to have any value of spherical equivalent that was myopic (<0 diopters [D]) at the first of 2 visits were included. METHODS: Cycloplegic refraction was measured using an autorefractor, axial eye length, and corneal power using an automatic combined noncontact partial coherence interferometer and keratometer. The accumulated number of daylight hours during the measurement period was calculated for each participant using an astronomical table. MAIN OUTCOME MEASURES: Change over 6 months in axial length, refraction, and corneal power. RESULTS: Accumulated hours of daylight ranged from 1660 to 2804 hours. Significant correlations were found between hours of daylight and eye elongation (P = 0.00), myopia progression (P = 0.01), and corneal power change (P = 0.00). In children with an average of 2782±19 hours of daylight, axial eye growth was 0.12±0.09 mm, myopia progression was 0.26±0.27 D, and corneal power change was 0.05±0.10 D per 6 months, whereas in children with an average of 1681±24 hours of daylight, axial eye growth was 0.19±0.10 mm, myopia progression was 0.32±0.27 D, and corneal power change was -0.04±0.08 D per 6 months. CONCLUSIONS: Eye elongation and myopia progression seem to decrease in periods with longer days and to increase in periods with shorter days. Children should be encouraged to spend more time outside during daytime to prevent myopia. FINANCIAL DISCLOSURE(S): The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Concepts: Cornea, Myopia, Refractive surgery, Lens, Astigmatism, Orthokeratology, Eyeglass prescription, Contact lens


: To assess the relationship between the thinnest corneal location and the steepest and maximum elevation corneal locations in subjects with keratoconus and the effect of gas permeable contact lens wear on the location of these points.

Concepts: Cornea, Lens, Orthokeratology, Contact lens, Contact lenses, Keratitis, Keratoconus, Scleral lens


PURPOSE: To evaluate the refractive and corneal topographical changes of overnight orthokeratology in myopia with two brands of contact lenses. METHODS: Fourty-four eyes of 22 myopic patients with manifest refraction spherical equivalent (MRSE) of -1.00 to -5.00 D (cylinder≤-1.0) were fitted with either DreamLens (Hanita Lenses Investments, Hanita, Israel) (group A) or Rinehart-Reeves (R&R; Danker Laboratories, Sarasota, FL) (group B) reverse-geometry lenses. Each subject eye was evaluated in regards to the uncorrected and corrected distance visual acuities, manifest refraction, slit lamp biomicroscopy, and corneal topography at each follow-up examination. RESULTS: The follow-up was 1 year. For groups A and B, the mean uncorrected distance visual acuity was -0.02±0.10 logMAR (20/20) and -0.08±0.12 logMAR (20/20) respectively at year-1 examination. The mean MRSE decreased from -2.70±0.9D to -0.50±0.08D in group A and -3.1±1.1 to -0.62±0.18D in group B at week-1; and remained stable thereafter in each group. For both groups, starting with week-1, the mean anterior best-fit sphere (ABFS) was statistically significantly flatter from baseline. A high correlation was found between the change in apical corneal power (ACP) and MRSE (r(1)=0.79, r(2)=0.71), and there was a good correlation between the change in ABFS and MRSE (r(1)=0.67, r(2)=0.64) in both groups. No significant ocular adverse events were observed during study. CONCLUSIONS: Both types of contact lenses safely and effectively decreased the myopic refractive error at 1 year follow-up. The refractive effect was mainly induced by the changes in the anterior corneal shape and the ACP.

Concepts: Visual acuity, Cornea, Myopia, Lens, Orthokeratology, Contact lens, Refractive error, Keratoconus


Purpose. To investigate the effects of 30 nights of overnight orthokeratology (OOK) on corneal epithelial permeability (Pdc) and corneal biomechanical properties. Methods. BE Retainer (Precision Technology Services) and Paragon CRT (Paragon Vision Sciences, Inc.) lenses were used. Visits were scheduled approximately 4 hours after awakening at baseline and after 1, 5, 10, 14, and 30 days of treatment. Pdc was measured at baseline and at Day 30, while corneal biomechanical properties and visual acuities (VA) were measured at all visits. Results. Thirty-nine neophytes and soft contact lens wearers completed the study. There was no difference in Pdc between baseline (ln(Pdc) [95% confidence interval (CI)] = -2.65 [-2.80, -2.50]) and Day 30 (ln(Pdc)[CI] = -2.68 [-2.85, -2.50]) (p=0.88). Corneal Hysteresis (CH) and Corneal Resistance Factor (CRF) reduced significantly from baseline (CH [CI] = 10.89 [10.59, 11.19] mm Hg and CRF [CI] = 10.35 [9.99, 10.72] mm Hg) to Day 30 (CH [CI] = 10.59 [10.31, 10.87] mm Hg and CRF [CI] = 9.58 [9.26, 9.89] mm Hg) (p=0.001 for CH and p<0.001 for CRF). Post-treatment VA did not reach baseline targets, and the difference was worse with low-contrast letters. Asians (n=18) had significantly worse VA than non-Asians (n=21) under most conditions through Day 5, and the difference extended through Day 14 with low-contrast letters under mesopic conditions. The percentage of participants who achieved 20/20 uncorrected was 17% Asians and 40% non-Asians after Day 1 and reached 69% Asians and 83% non-Asians at Day 30. Conclusions. 30 nights of OOK did not alter Pdc when measured 4 hours after awakening. OOK caused CH and CRF to decrease, but the changes were not clinically significant compared to diseased and post-surgical cases. Asians, who had lower baseline CH in this study, responded slower to OOK based on early uncorrected VA and over-refraction measurements.

Concepts: Measurement, Epithelium, Cornea, Myopia, Refractive surgery, Orthokeratology, Contact lens, Paragon Vision Sciences


Mini-scleral lenses are an increasingly popular contact lens modality; however, there are relatively few reports regarding the unique aspects of their fitting and potential complications. We report a complication of mini-scleral lens wear in a 44-year-old female patient using the lenses for keratoconus. Her mini-scleral contact lenses were non-fenestrated and fitted to vault over the cornea and seal at the periphery. The patient presented with an acute red eye (non-ulcerative keratitis), characterised by unilateral severe conjunctival and limbal hyperaemia, corneal infiltration and pain. Refitting the lens to increase the corneal vault clearance did not prevent recurrence of the keratitis, some five months later. Successful prevention of further episodes of the acute red eye was achieved through improved patient compliance with lens cleaning, disinfection and lens case procedures. Lens hygiene may be particularly important for mini-scleral lenses with a sealed fitting.

Concepts: Eye, Cornea, Lens, Orthokeratology, Contact lens, Contact lenses, Keratitis, Keratoconus


PURPOSE. TO INVESTIGATE THE SHORT-TERM EFFECT OF ORTHOKERATOLOGY (ORTHO-K) LENS WEAR ON THE ANTERIOR SEGMENT LENGTH FOR VALIDATING THE USE OF AXIAL LENGTH FOR MONITORING MYOPIC PROGRESSION AFTER ORTHO-K TREATMENT. METHODS. THIRTY-SEVEN AND 39 SUBJECTS (AGED 7-10) WERE RANDOMLY ASSIGNED TO WEAR ORTHO-K AND SINGLE-VISION SPECTACLES, RESPECTIVELY. CENTRAL CORNEAL THICKNESS (CCT), ANTERIOR CHAMBER DEPTH (ACD), CRYSTALLINE LENS THICKNESS (LT), AND ANTERIOR SEGMENT LENGTH (ASL: summation of CCT, ACD and LT) were measured before and 6-month after the treatment under cycloplegia. Changes in these parameters were evaluated and compared between the two groups of subjects. Results. There were no significant between-group differences in the baseline data (p>0.37). After 6 months of lens wear, in the ortho-k group, CCT was significantly reduced by 0.009±0.009 mm (p<0.001) while ACD and LT remained unchanged (p>0.15). In the spectacle group, ACD was significantly increased by 0.01±0.03 mm (p=0.008) while CCT and LT remained unchanged (p>0.06). In both groups of subjects, ASL did not changed significantly but axial length was significantly increased by 0.10±0.10 mm and 0.20±0.11 mm in the ortho-k and the spectacle groups, respectively (p<0.001). Conclusions. Eyeball elongation occurred in children wearing both ortho-k and single-vision spectacles. Since, ASL was not affected by ortho-k treatment, axial length measured reflects the true growth of the eyeball and is a valid parameter for monitoring myopic progression in ortho-k treated eyes.

Concepts: Eye, Cornea, Myopia, Refractive surgery, Lens, Orthokeratology, Contact lens, Accommodation


Scleral contact lenses (ScCL) have gained renewed interest during the last decade. Originally, they were primarily used for severely compromised eyes. Corneal ectasia and exposure conditions were the primary indications. However, the indication range of ScCL in contact lens practices seems to be expanding, and it now increasingly includes less severe and even non-compromised eyes, too. All lenses that partly or entirely rest on the sclera are included under the name ScCL in this paper; although the Scleral Lens Education Society recommends further classification. When a lens partly rests on the cornea (centrally or peripherally) and partly on the sclera, it is called a corneo-scleral lens. A lens that rests entirely on the sclera is classified as a scleral lens (up to 25mm in diameter maximum). When there is full bearing on the sclera, further distinctions of the scleral lens group include mini-scleral and large-scleral lenses. This manuscript presents a review of the current applications of different ScCL (all types), their fitting methods, and their clinical outcomes including potential adverse events. Adverse events with these lenses are rare, but the clinician needs to be aware of them to avoid further damage in eyes that often are already compromised. The use of scleral lenses for non-pathological eyes is discussed in this paper.

Concepts: Eye, Cornea, Lens, Orthokeratology, Contact lens, Contact lenses, Keratoconus, Scleral lens


A 76 year old male presents with a corneal perforation in a phthisical eye. Definitive treatment in the form of an evisceration was delayed by 38 days. During this period a bandage contact lens prevented extrusion of ocular contents through an enlarging corneal perforation. This case demonstrates that a bandage contact lens can be effective in the immediate management of large corneal perforations whilst awaiting urgent definitive treatment.

Concepts: Eye, Cornea, Lens, Orthokeratology, Contact lens, Keratitis, Corneal ulcer