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International Newsletter and Forum on Rigid Gas Permeable Contact Lenses, Corneal Shape, Health and Vision |
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From Density to Destiny
The scleral lens presentation density at the recent European Contact Lens Society of Ophthalmologists (ECLSO) meeting in Izmir (TU) was enormous! And that was just the oral presentations. I also cannot recall any negative effects reported - it was all positive news from different parts of the world, including the more remote regions, on how sclerals can help many patients with various conditions. One paper from Malaysia from Mutalib Abdul et al looked at stromal keratocyte density in corneal GPs vs. scleral GPs. They found that corneal GP lens wear led to the loss of stromal keratocytes and hence a lower keratocyte density in keratoconus eyes compared to wear of scleral GPs. Could this possibly be another reason to consider scleral GPs for keratoconus and potentially lead to a further increase of scleral lens density worldwide? It may be scleral lenses' destiny.
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Safety and Efficacy
Myopia control was also the topic of an interesting session at the aforementioned ECLSO meeting, including soft lens, orthokeratology and pharmaceutical intervention. Although soft lenses seem to have gained momentum, orthokeratology is generally cited as the modality with the best track record so far for optical intervention. The safety and efficacy are discussed in a number of recent peer reviewed optometry and ophthalmology journals.
Molly Smith and Jeff Walline present a review paper in the open-access journal 'Adolescent Health, Medicine and Therapeutics'on the topic. 'Both orthokeratology and soft bifocal contact lenses have shown to slow myopia progression by slightly less than 50% in most studies' with few risks, they state.
Wen et al published an overview in the Journal of Ophthalmology (open-access): a systemic review and a meta-analysis on the 'Efficacy and Acceptability of Orthokeratology for Slowing Myopic Progression in Children.'
Zhou et al investigated the long-term clinical effects of ortho-k in 30 high-myopia children (mean -7.34±0.91D) with a 5-year follow-up period. The mean age of the children was 15±2 years. The article published in the Chinese journal of Ophthalmology revealed that the axial elongation was retarded by using orthokeratology in high-myopia children, and no complications were reported.
Cheng et al studied 126 orthokeratology patients in a 24-week follow-up study. No severe complications were noted. Overnight orthokeratology with lenses made with high-permeability material were reported to be effective and safe in this study published in Contact Lens & Anterior Eye.
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Topographic and Pachymetric Classification
 Toprak et al, in Contact Lens & Anterior Eye, investigate the combination of topographic (Scheimpflug) and pachymetric parameters to diagnose keratoconus. The study included 183 eyes of 183 patients with keratoconus (keratoconus group) and 131 eyes of 131 age and sex-matched healthy subjects (control group). Although Kmax and thinnest pachymetry (TP) appear to have high diagnostic ability in keratoconus, the use of either parameter in isolation might be unsatisfactory in differential diagnosis. Therefore, the Kmax2/TP ratio has been introduced, which reflects major characteristics of keratoconus and might be used as an important criterion in keratoconus diagnosis.
On a slightly different topic: a new clinico-tomographic classification and management algorithm for Descemet's membrane detachment was developed by Jacob et al, also published in Contact Lens & Ant Eye.
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Keratoconus Management
 Clark Chang, in the September issue of Contact Lens Spectrum, looks at 'Corneal Cross-Linking in keratoconus; Past, Present, and Future' and calls it a changing paradigm in keratoconus management. At the same time, Ed Bennett asks the question: 'Are Scleral Lenses Impacting Corneal Transplants?' in the same issue of Contact Lens Spectrum. A survey to the GPLI advisory board had 34 respondents, of which 26 believed that scleral lenses had led to reduced levels of corneal transplant referrals. Based on this, the author states that: 'A study looking at the impact of scleral lenses on the incidence of corneal transplants is indicated, and the results could be compelling.' To top things off: Thuy-Lan Nguyen looks at 'Fitting Contact Lenses for Athletes Who Have Keratoconus' in the same issue of Contact Lens Spectrum.
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Kids-Contact-Lens-Clinic
For one of the best lectures that you will ever see on the topic of myopia control: Jeff Walline presented a recent GPLI webinar titled 'Myopia Control 2015.' On time spent outdoors, it was stated that this seems to prevent myopia, but is not effective in slowing down myopia progression once a child is myopic. The webinar further looks at the management of myopia progression with soft and (R)GP lens options and the role of atropine. It mentions a study in which 1% and 0.1% atropine was tested, with 0.01% used as a control group - or at least that's what they thought. The 0.01% was very effective, and the rebound effect is actually slower with this lower dose. The question is, according to the webinar, whether atropine actually results in a decrease in axial elongation - as orthokeratology (OK) and soft dual-focus lenses seem to. In the latter two cases, larger treatment zones and more near add seem better. Which lens option is most effective really depends on the patient: but if you want a contact lens-free solution during daytime hours, then OK seems to be the way forward. Astigmatism is also easy to correct with OK. Combining 0.01% atropine, which leads to a 1mm increase in pupil size, with, for instance, OK may prove to be a good option going forward. The largest group of patients in the Kids-Contact-Lens-Clinic that Walline manages end up in OK treatment.
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A Scleral Device after Severe Ocular Infection
This case report illustrates the condition of an eye with a significant opacification and scarring of the cornea covering part of the pupil area. A 38-year-old woman presented to the clinic concerned with her visual quality. She had been wearing daily disposable silicone hydrogel contact lenses for three years. Eleven months prior to this visit, she indicated that she'd had a Pseudomonas aeruginosa infection. When the patient left the hospital, her visual acuity OS was 0.1. This improved to 0.2 after 1 month, and a year following that her best-corrected visual acuity was reported to be 0.4 (with glasses). The patient now wears a scleral lens (Senso Mini Scleral Lens from Procornea, Eerbeek, the Netherlands) for 8-10 hours a day without any compromise. Her vision OS is better than 0.8, and the lens exhibits the same behavior on-eye as in the initial visits. It is important to note that the symptoms of ocular dryness and irritation have decreased dramatically since she was fitted with scleral lenses.
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I-site is an educational newsletter that is distributed on a monthly basis and provides an update on rigid gas permeable related topics (scientific research, case reports and other publications worldwide). I-site is objective and non-political. Its editor Eef van der Worp, optometrist, PhD, FAAO, FBCLA, FIACLE, FSLS is a lecturer for a variety of industry partners, but is not related to any specific company. Please contact us at: i-site@netherlens.com.
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