While still in early stages of testing, researchers in Boston and Genoa, Italy, found that topical administration of omega-3 and omega-6 fatty acids led to a significant decrease in dry-eye signs and inflammatory changes at both cellular and molecular levels in a mouse model.


Formulations containing alpha-linolenic acid (ALA) and linoleic acid (LA), combined ALA and LA, or vehicle alone, were applied  to dry eyes induced in mice. A masked observer assessed fluorescein staining and the number and maturation of corneal CD11b+ cells in the different treatment groups. Real-time polymerase chain reaction was used to quantify expression of inflammatory cytokines in the cornea and conjunctiva.


Dry-eye induction significantly increased corneal fluorescein staining; CD11b+ cell number and major histocompatibility complex Class II expression; corneal IL-1 and tumor necrosis factor (TNF-alpha) expression; and conjunctival IL-1, TNF-alpha, interferon, IL-2, IL-6 and IL-10 expression. Treatment with ALA significantly decreased corneal fluorescein staining compared with both vehicle and untreated controls. Additionally, ALA treatment was associated with a significant decrease in CD11b+ cell number, expression of corneal IL-1 and TNF-alpha, and conjunctival TNF-alpha.


They conclude that topical application of ALA omega-3 fatty acid may be a novel therapy to treat the clinical signs and inflammatory changes accompanying dry-eye syndrome.


(Arch Ophthalmol 2008;126:219-225.)

Rashid S, Jin Y, Ecoiffier T, Barabino S, Schaumberg D, Dana, R.

 


IOP at the End of Cataract Surgery


A group at Southend University Hospital, Essex, U.K., assessed the accuracy of estimating intraocular pressure at the end of cataract surgery in 69 eyes having phacoemulsification cataract surgery without complications. In stage 1, the surgeon estimated IOP using digital pressure at the end of surgery; a second investigator checked the actual IOP using a handheld tonometer. They then compared estimated and true values. In a second group, IOP was measured at the end of surgery in 30 eyes using a specifically designed tonometer, the Ocular Kasaby Barraquer 20/30 (OKBT-20/30) (Ocular Instruments Inc.). The true values were remeasured using the handheld tonometer to verify the OKBT-20/30's accuracy.


In stage 1, 37.7 percent of the estimates were outside the "acceptable" IOP range of 10 mmHg or higher to 30 mmHg or lower. Accuracy of estimates decreased toward the extremes of IOP. This suggests that eyes with IOP values outside the acceptable range are likely to be left as such at the end of surgery. In stage 2, when the IOP was measured with the new instrument and rechecked with the electronic tonometer, 93.3 percent of eyes had an IOP within the reference range of 20 to 30 mmHg; 62.3 percent of eyes had an IOP within this range when estimated. Because the digital estimate can be misleading, the group recommends that the tonometer or a similar device should be used routinely to ensure each eye is left with a desirable IOP at the end of cataract surgery.


(J Cataract Refract Surg 2008;34:258-61.)

Antao SF, Kasaby H.

 


Glaucoma Drugs and Post-LASIK Myopic Regression


Preliminary data from a study at two Japanese sites shows that antiglaucoma drugs are effective for the reduction of refractive regression, especially of the spherical errors, after LASIK.


The prospective, non-randomized clinical trial included 27 eyes with mean myopic regression ±SD of -1.26 ±0.48 D (range, -0.50 to -2.25 D) after LASIK. Nipradilol 2.5% was administered topically twice daily to the regressive eyes. The refraction (spherical equivalent, astigmatism), IOP, pachymetry, geometry and refractive power of the cornea before and three months after treatment were all recorded.


Mean manifest refraction was improved significantly from -1.02 ±0.52 D to -0.44 ±0.39 D (p<.001). However, mean manifest astigmatism was changed from -0.55 ±0.30 D to -0.49 ±0.22 D, but the difference was not significant (p=0.23). The IOP was decreased significantly from 11.4 ±2.4 mmHg to 9.4 ±1.3 mmHg (p<0.001). Central corneal thickness was not changed significantly from 505.2 ±39.3 µm to 503.6 ±38.7 µm (p=0.61). The posterior corneal surface was shifted posteriorly by 9.1 ±8.2 µm, and the total refractive power of the cornea was decreased significantly, by 0.63 ±0.62 D (p<.001), at three months after application. The investigators suggest that backward movement of the cornea may occur, possibly flattening the corneal curvature by lowering the IOP. Reduction of the IOP may contribute to improving regression after keratorefractive surgery.


(Am J Ophthalmol 2008;145:233-238.)

Kazutaka Kamiyaa, Daisuke Aizawaa, Akihito Igarashib, Mari Komatsub, Kimiya Shimizua

 


Does In Vitro Susceptibility Predict Clinical Outcome?


Are clinical outcomes in bacterial keratitis associated with antibiotic susceptibility? An Indian study tested that by retrospectively assessing data and samples from a completed randomized clinical trial.


Forty-two patients were enrolled with culture-confirmed bacterial keratitis at Aravind Eye Hospital in South India. All patients received topical moxifloxacin and were randomized to receive either topical prednisolone phosphate or placebo. Outcomes included time to epithelialization, best spectacle-corrected VA and infiltrate/scar size at three months. Bacterial isolates were cultured, and minimum inhibitory concentration to moxifloxacin was measured using Etests.


MIC was associated with three-month infiltrate/scar size: each two-fold increase in MIC was associated with a 0.33-mm average diameter increase in scar size (p=.01). MIC was not, however, associated with three-month BSCVA (p=0.71) or time to epithelialization (p=0.35). A larger, multicenter trial should provide information on whether this association is maintained across subgroups of organisms, the group concludes.


(Am J Ophthalmol 2008;145:409-412.)

Chena A, Prajnab L, Srinivasan M, Mahalakshmib R, Whitcher J, McLeod S, Lietman T, Acharya N.



Bevacizumab for Corneal Neovascularization


Short-term results of a Canadian study suggest that subconjunctival bevacizumab is well-tolerated and associated with a partial regression of corneal neovascularization. Researchers retrospectively reviewed the charts of 10 consecutive patients with corneal neovascularization who received subconjunctival injections of bevacizumab (2.5 mg/0.1 mL. Masked observers reviewed digital photographs for density, extent and centricity of corneal vascularization. Image analysis was used to determine the area of cornea covered by neovascularization as a percentage of the total corneal area.


During 3.5 ±1.1 months of follow-up, seven patients showed partial regression of vessels. The extent decreased from 6.0 ±1.2 (SD) clock hours before the injection to 4.6 ±1.0 clock hours after bevacizumab (p=0.008). Density decreased from 2.7 ±0.2 to 1.9 ±0.3, respectively. (p=0.007). No change was noticed in the centricity of corneal vessels. Corneal neovascularization covered, on average, 14.8 percent ±2.5 percent of the corneal surface before the injections, compared with 10.5 percent ±2.8 percent (p=0.36) after bevacizumab, a decrease of 29 percent.


(Cornea 2008;27:142-147.)

Bahar I, Kaiserman Igor, McAllum P, Rootman D, Slomovic A.



VA in AMD Patients with Snellen vs. ETDRS Charts


A study at the University of California, La Jolla, reports that Early Treatment Diabetic Retinopathy Study measurements yielded better VA, particularly with vision <20/200 in patients with age-related macular degeneration. They recommend that the findings be considered when comparing outcomes in clinical practices (which typically measure VA using standard Snellen charts) with outcomes from clinical trials (which typically measure VA using ETDRS charts).


The group randomly measured VA with Snellen and ETDRS charts in 104 patients (190 eyes); 80 participants (142 eyes) had some degree of AMD and a recorded difference in VA measured by both charts in logMAR notations.


Overall, the mean Snellen VA was 0.78 logMAR (20/120), and the mean ETDRS VA in the same eye was 0.54 logMAR (20/70; p<0.001). In the low-vision group (<20/200), represented by patients with AMD, the average difference in number of lines was considerably larger than in the good vision range (>20/30). On average, 20/200 on Snellen was 20/95 on ETDRS (>3 lines difference), and 20/30 on Snellen was 20/25 on ETDRS (<1). The results show poor agreement between the Snellen and ETDRS charts, and it was more pronounced in the group with poor vision.


(Ophthalmology 2008;115:319-23.)

Falkenstein IA, Cochran DE, Azen SP, Dustin L, Tammewar AM, Kozak I, Freeman WR.