Results of a Phase I/II feasibility study of the 60-electrode Argus II retinal prosthesis system show that 54 percent (n=15) of blind subjects implanted with the prosthetic were able to perform a motion detection task they could not do with their native vision. This confirms that electrical stimulation of the retina provides spatial information from synchronized activation of multiple electrodes.
Twenty-eight blind subjects (bare light perception or worse in both eyes) with retinitis pigmentosa were implanted with the Argus II. The experiment measured patient ability to detect the motion of a high-contrast moving bar on a flatscreen monitor in three conditions: with the prosthesis system on and a one-to-one mapping of spatial information; with the system off; and with the system on with randomly scrambled spatial information.
Fifteen subjects performed the task better with their prosthesis system than with their residual vision. Two subjects had better performance with their residual vision while no difference was found for the remaining 11 patients. Of the 15 better-performing subjects, 11 were available for follow-up testing, and 10 had significantly better performance with normal rather than scrambled spatial information.
JAMA Ophthalmol 2013;131:2:183-189.
Dorn J, Ahuja A, Caspi A, de Cruz L, et al.
EBAA Does Not Recommend Antifungal Donor Storage Media
After reviewing adverse reactions reported to the Eye Bank Association of America through an online adverse reaction reporting system, the EBAA has determined that while there has been a nonsignificant increasing trend in the rate of fungal infection after corneal transplant, it is not sufficiently compelling to pursue antifungal supplementation of donor storage media.
Adverse reactions reported between January 1, 2007 and December 31, 2010 were reviewed to identify cases of recipient fungal infection. Data regarding the donor, donor cornea, recovery and processing, mate culture and clinical course of the recipients was collected. Out of 221,664 corneal transplants performed using corneal tissue distributed by domestic eye banks, 31 cases of culture-proven fungal keratitis (n=14) and endophthalmitis (n=17) were reported (1.4 cases per 10,000 transplants performed).
Fungal infections were more commonly reported after endothelial keratoplasty procedures (0.022 percent) than penetrating keratoplasty procedures (0.012 percent), but the difference was not statistically significant (p=0.076). No association was found between fungal infection after endothelial keratoplasty and whether the lamellar tissue cut was performed by the surgeon or the eye bank technician. Seventy-three percent (16 of 22) of the fungal cultures performed on the mate corneas were positive, with infection developing in 67 percent (10 of 15) of recipient eyes (endophthalmitis in six and keratitis in four eyes).
Aldave A, DeMatteo J, Glasser D, Tu E, et al.
Evaluation of Corneal Astigmatic Marking Methods
In a randomized, examiner-masked clinical trial in Austria, doctors compared four devices used to mark the cornea before astigmatism-reducing surgery, determining that all the devices showed a slight deviation to the horizontal reference meridian. Because small deviations of the meridian can result in a relevant reduction in the astigmatism-reducing effect with toric intraocular lenses, accurate marking of the cornea before surgery is critical due to the variable cyclotorsion caused by a change from the upright to the supine position.
Patients (n=60) were randomly allocated to one of four groups for preoperative corneal marking in the sitting position. The four methods used were marking at the slit lamp with an insulin needle, a pendular marker, a bubble marker and a tonometer marker. The marks were then documented with a standardized photographic technique, and the rotational deviation and vertical misalignment were assessed.
The pendular-marking device showed the least rotational deviation to the reference meridian (mean 1.8 degrees). There was no statistically significant difference between slit- lamp marking and pendular marking (p=0.05); however, there was a significant difference between the pendular marker and the bubble marker and between the pendular marker and the tonometer marker (p=0.01 and p<0.01). The least vertical misalignment was observed with the slit lamp-marking device (mean 0.28 mm). There was no statistically significant difference in vertical misalignment between the four groups.
J Cataract Refract Surg 2012;38:2094-2099.
Popp N, Hirnschall N, Maedel S, Findl O.
Wavefront Sensor Excellent at Measuring HOAs
Researchers in Spain assessed the intrasession and intersession precision of ocular, corneal and internal higher-order aberrations measured using an integrated topographer and Hartmann-Shack wavefront sensor (Topcon KR-1W) in refractive surgery candidates. The intrasession repeatability was high; therefore, the device’s ability to measure HOAs in a reliable way was excellent. Under intersession reproducibility conditions, dependable corneal spherical aberration measurement were provided.
In order to measure intrasession repeatability, one experienced examiner measured eyes nine times successively. To study intersession reproducibility, the same clinician obtained measurements from another set of eyes in two consecutive sessions one week apart. Ocular, corneal and internal HOAs were obtained. Coma and spherical aberrations, 3rd- and 4th-order aberrations and total HOAs were calculated for a 6 mm pupil diameter.
For intrasession repeatability (75 eyes), excellent intraclass correlation coefficients were obtained (ICC>0.87), except for internal primary coma (ICC=0.75) and 3rd-order (ICC=0.72) HOAs. Repeatability precision (1.96 x SW) values ranged from 0.03 μm (corneal primary spherical) to 0.08 μm (ocular primary coma). For intersession reproducibility (50 eyes), ICCs were good (>0.8) for ocular primary spherical, 3rd-order and total higher-order aberrations; reproducibility precision values ranged from 0.06 μm (corneal primary spherical) to 0.21 μm (internal 3rd order) with internal HOAs having the lowest precision (≥0.12 μm). No systemic bias was found between examinations on different days.
J Cataract Refract Surg 2013;39:242-249.
López-Miguel A, Martinez-Almeida L, González-Garcia M, Coco-Martin M, et al.
A.M. Dose of Once-daily Glaucoma Rx More Convenient
Canadian researchers have determined that patients prefer morning administration of once-daily glaucoma medications to evening administration. While adherence decreases from the first to second month after initiation of treatment, recommending morning administration to patients may lead to greater medication adherence.
Thirty patients newly diagnosed with glaucoma or ocular hypertension requiring IOP reduction were started on travoprost eye drops and randomized to either morning or evening administration for one month. They were then crossed over to the opposite dosing schedule for the following month. Adherence was monitored using an automated dosing aid, and compared between morning and evening dose and first vs. second month dosing. Demographic characteristics were obtained and treatment effects were measured; patients also completed a post-study questionnaire regarding the convenience of the two dosing regimens.
Overall patient adherence was good (89.3 percent), and there was no statistically significant difference (p=0.07) in adherence between morning dosing (90.9 percent) and evening dosing (87.3 percent). Adherence in the first month (91.7 percent) was superior to the second month (86.5 percent). There was no significant difference in IOP response between morning and evening dosing.
J Glaucoma 2013;22:1-4.
Ford B, Gooi M, Carlsson A, Crichton A.
SD-OCT Use Shortens Duration Of Postop Prone Positioning
A retrospective review of patients with macular holes undergoing 23-ga. pars plana vitrectomy and intraocular gas tamponade concludes that confirming early closure of macular holes with spectral domain optical coherence tomography imaging can serve as an important guide to significantly shortening the duration of patient prone positioning while maintaining a high closure rate.
SD-OCT was done postop day one. Patients remained face down for two more days if the macular hole was closed, or six more days if the macular hole was open or indeterminate. There were eight Stage 2, 12 Stage 3 and 12 Stage 4 macular holes. On postop day one, 24 holes were confirmed closed by SD-OCT and patients were instructed to remain facedown for two more days. Twenty-three of the 24 holes remained closed. Eight holes were open or indeterminate on postop day one, and the patients remained face down for six more days. Six of the eight holes (75 percent) were closed at their last follow-up. The overall closure rate was 29/32 (90.6 percent), with an average follow-up of 334 days.
Shah S, Manjunath V, Rogers A, Baumal C, et al.