BCom(Hons) BOptom PGCOT FAAO
Tasmania State President, Cornea and Contact Lens Society of Australia
Contact lenses for glaucoma? Latanoprost-eluting lenses help glaucomatous monkeys
A preclinical animal efficacy study indicates that contact lens drug delivery may be a future option for the treatment of glaucoma and a platform for prostaglandin drug delivery.
Researchers assessed the IOP-lowering effect of latanoprost-eluting low-dose contact lenses (CLLO), high-dose contact lenses (CLHI) or daily latanoprost ophthalmic solution in glaucomatous eyes of cynomolgus monkeys.
Each monkey consecutively received one week of continuous-wear CLLO, three weeks without treatment, five days of latanoprost drops, three weeks without treatment, and one week of continuous-wear CLHI.
Latanoprost ophthalmic solution resulted in IOP reduction of 5.4 ± 1.0 mmHg on day three and peak IOP reduction of 6.6 ± 1.3 mmHg on day five. The CLLO reduced IOP by 6.3 ± 1.0, 6.7 ± 0.3, and 6.7 ± 0.3 mmHg on days three, five and eight, respectively. The CLHI lowered IOP by 10.5 ± 1.4, 11.1 ± 4.0, and 10.0 ± 2.5 mmHg on days three, five and eight, respectively. For the CLLO and CLHI, the IOP was statistically significantly reduced compared with the untreated baseline at most time points measured. The CLHI demonstrated greater IOP reduction than latanoprost ophthalmic solution on day three (p = 0.001) and day five (p = 0.015), and at several time points on day eight (p < 0.05).
Researchers concluded that sustained delivery of latanoprost by contact lenses is at least as effective as delivery with daily latanoprost ophthalmic solution. They suggested that more research is needed to determine the optimal continuous-release dose that would be well-tolerated and maximally effective.
Ophthalmology 2016; 123: 10: 2085-2092. doi: 10.1016/j.ophtha.2016.06.038.[Epub 2016 Aug 29]
Does keratoconus progress beyond age 30?
According to a study published in the British Journal of Ophthalmology, a significant percentage of people with keratoconus exhibit progression beyond age 30.
To determine if significant progression of disease occurs in older, non-contact lens wearing subjects with keratoconus and to identify potential predictive factors, researchers retrospectively analysed clinical and computerised corneal topography records of 449 subjects with keratoconus.
Of those assessed, 43 eyes of 27 patients (6.01 per cent) met inclusion criteria, with median age 38.45 (12.86) years at baseline and median follow-up 4.36 (8.68) years. Topographic parameters assessed included maximum keratometry (Kmax), steep keratometry (Ksteep), flat keratometry (Kflat), inferior-superior (I-S) ratio and the surface asymmetry and regularity (surface asymmetry index and surface regularity index) indices.
The study found that there was a significant increase in Kmax (0.30 [1.21] D), Ksteep (0.27 [0.90] D), Kflat (0.34 [1.12] D) and I-S (0.26 [0.82] D) between baseline and final review, p < 0.05.
Notably, 18.6 per cent to 25.6 per cent of eyes demonstrated greater than or equal to 1.00 D increase in one or more of four principal topographic parameters (Kmax, Ksteep, Kflat, I-S ratio), while 18.5 per cent to 37.0 per cent of subjects had greater than or equal to 1.00 D increase in these parameters in at least one eye over the study period. However, less than 10 per cent of eyes exhibited greater than or equal to 1.00 D increase per year in all topographic parameters. The only significant predictor of progression was follow-up time.
The study authors recommended that older subjects with keratoconus should be monitored for progression, particularly with respect to possible corneal collagen cross-linking or astigmatic correction in cataract surgery.
Br J Ophthalmol 2016 Oct 11. doi: 10.1136/bjophthalmol-2016-308682. [Epub ahead of print]
Is purchasing contacts from the prescriber associated with better patient habits?
Researchers conducted an online survey to compare the habits of soft contact lens (SCL) wearers who made their purchases from an eye-care practitioner (ECP), on the internet or over the phone, or at a retail place unaffiliated with the eye-care practitioner who conducted their eye examination. Their results raise questions about the assumed link between patient safety and professional oversight at the time of purchase.
In the survey, 1,057 adult SCL wearers were asked about risk factors for SCL-related complications. A total of 646 SCL wearers (age 44 ± 12 years, 17 per cent male) bought lenses at their ECP; 104 at retail (age 45 ± 13 years, 28 per cent male), and 218 on the internet (45 ± 12 years, 18 per cent male). More males bought at retail (p = 0.021). Internet purchases were more likely to be of hydrogel SCLs (45 per cent internet, 34 per cent ECP, 29 per cent retail, p = 0.0034).
Internet purchasers were more likely to have more than one year between eye examinations (34 per cent internet, 21 per cent ECP, 17 per cent retail, p = 0.007) and less likely to pay for SCLs with insurance (19 per cent internet, 39 per cent ECP, 29 per cent retail, p < 0.0001). Overnight wear, ‘topping up’, use of reusable SCLs, and tap water exposures were similar across groups, as were knowledge and attitudes on SCL safety.
The authors concluded that the purchase location of SCL wearers showed limited association with known risk factors for SCL-related inflammation. Wearers who purchased lenses on the internet reported less frequent eye examinations and were more likely to be wearing hydrogel SCLs. Males were more likely to purchase SCLs at retail, not where they had eye examinations.
In this sample, closer access to the eye-care practitioner by in-office SCL purchase did not improve the patient’s habits or reduce the prevalence of risk behaviours, leaving the relationship between proximity to eye-care practitioners and the risk of complications unclear.
Cont Lens Anterior Eye 2016 Aug 12. doi: 10.1016/j.clae.2016.08.003. [Epub ahead of print]
Dual focus soft contacts match ortho-K in countering myopic progression
According to a study reported in Optometry & Vision Science, both orthokeratology and dual focus soft contact lenses are effective strategies for targeting myopia progression in the clinic.
Researchers reviewed the clinical outcomes for patients attending a specialist myopia control clinic at The University of Auckland Optometry School, New Zealand and presented a comparative case series of 110 patients (aged 4–33 years, mean: 12.13 ± 4.58 years, 62 per cent female) who attended the clinic between 2010 and 2014.
A total of 56 patients were prescribed orthokeratology (ortho-K), 32 wore dual focus soft contact lenses, and 22 received advice only. Mean follow-up time for ortho-K and for dual focus soft contact lenses was the about the same at 1.3 years and 1.33 years, respectively.
There was a significant reduction in the annualised myopia progression in both groups (ortho-K: -1.17 ± 0.55 to -0.09 ± 017 D/yr, p < 0.001; dual focus soft contact lens: -1.15 ± 0.46 to -0.10 ± 0.23 D/yr, p < 0.001). There was no difference between ortho-K and dual focus lens treatment efficacy (p = 0.763), nor in axial or vitreous chamber length changes after treatment (p = 0.184).
Researchers concluded that both ortho-K and dual focus soft contact lenses are effective strategies for targeting myopia progression in the clinic. ‘We saw no significant difference in the efficacy of the two methods,’ they wrote. ‘We believe there are very few barriers for any contact lens practitioner to be actively promoting myopia control treatment to at-risk patients.’
Optom Vis Sci 2016; 93: 9: 1120-1126. doi: 10.1097/OPX.0000000000000957.
Which multipurpose solution is best for protein deposits?
The ability of lens care solutions to remove protein from lenses varies depending on the care solution composition and the polymeric make-up of the contact lens material, according to a report of a study in Optometry and Vision Science.
To evaluate the effect of four contemporary lens care solutions on total protein, total lysozyme, and active lysozyme extracted from three contact lens materials, researchers recruited contact lens wearers and randomly assigned them to daily wear of variously etafilcon A, galyfilcon A, or senofilcon A for two weeks.
Four lens care solutions (Biotrue, OPTI-FREE PureMoist, RevitaLens OcuTec, and ClearCare) were used by each subject in random order with a new pair of lenses after an interval between solutions of at least four days. After two weeks of daily wear, contact lenses were collected for analysis.
Higher levels of total protein were extracted from etafilcon A when used with Biotrue compared to other solutions (p = 0.0001). There were higher levels of total lysozyme extracted from galyfilcon A lenses when used with PureMoist than with Biotrue or ClearCare (p < 0.006). Higher total lysozyme was extracted from senofilcon A when used with RevitaLens OcuTec compared to Biotrue (p = 0.002). Lower lysozyme activity was recovered from senofilcon A lenses with RevitaLens OcuTec when compared to all other care solutions (all p < 0.004). When Biotrue, PureMoist, or RevitaLens OcuTec was used, higher total lysozyme was extracted from galyfilcon A compared to senofilcon A (p < 0.01). When RevitaLens OcuTec was used, higher levels of active lysozyme were extracted from galyfilcon A compared to senofilcon A (p = 0.02).
Optom Vis Sci. 2016; 93: 8: 963-72. doi: 10.1097/OPX.0000000000000928.
More evidence for IPL
A new Canadian study suggests that intense pulsed light (IPL) therapy is an effective treatment for dry eye disease.
In a multicentre cohort study, clinical data were reviewed from 100 patients with diagnosis of meibomian gland dysfunction (MGD) and dry eye disease who underwent IPL therapy from September 2012 to December 2014.
On average, patients underwent four IPL sessions. In their review, the researchers found that there was a significant decrease in scoring of lid margin oedema (mean = -0.3; range -1.5 to 0), facial telangiectasia (mean = -0.7; range -2.5 to 0), lid margin vascularity (mean = -1.2; range -2.5 to 0), meibum viscosity (mean = -1.1; range -3 to 0) and OSDI score (mean = -9.6), all with p < 0.001.
There was also a significant increase in oil flow score (mean = 0.9, range -0.5 to 2) and tear break up time (mean = 3.4 seconds, range -2 to 7), both p < 0.001. No significant changes in intraocular pressure or acuity were noted and there were no cases of adverse ocular effects.
The authors conclude that the change in objective signs and OSDI scores show IPL to be a safe and effective treatment for patients with evaporative dry eye disease.’
Can J Ophthalmol 2016; 51: 4: 249-253. doi: 10.1016/j.jcjo.2016.01.005.[Epub 2016 Jun 22]