California doctors utilized a Scottish database of patients receiving refractive surgery to describe the factors that influence intraocular pressure change after myopic and hyperopic LASIK and photorefractive keratectomy. Myopic procedures lowered measured IOP more than hyperopic procedures; this decrease was proportional to the amount of refractive error corrected. Independent of the refractive error correction, the creation of the lamellar LASIK flap decreased IOP by 0.94 mmHg. The doctors also developed a best-fit model for IOP change that may allow better interpretation of post-laser vision correction IOP values.
The doctors searched the Optical Express database for all patients undergoing primary PRK or LASIK with a refractive target of emmetropia between January 1, 2008 and October 5, 2011. Data were extracted on procedure specifics; preoperative central corneal thickness; IOP (using noncontact tonometry); manifest refraction; average keratometry; age; gender; and postoperative IOP at one week, one month and three months. A linear mixed methods model was used for data analysis, and the main outcome measure was any change between preoperative IOP and IOP up to one month postop.
A total of 174,666 eyes of 91,204 patients were analyzed. Hyperopic corrections experienced a smaller IOP decrease than myopic corrections for both PRK and LASIK (p<0.0001). Patients who underwent LASIK had a 0.94 mmHg greater IOP decrease than patients who underwent PRK (95 percent confidence interval, 0.89 to 0.98; p<0.0001), reflecting the effect of the lamellar flap. The decrease in IOP was linearly related to preoperative manifest spherical equivalent for myopic PRK and LASK (p<0.0001), weakly correlated with preoperative MSE after hyperopic LASIK and not related to preoperative MSE after hyperopic PRK. The single greatest predictor of IOP change was preoperative IOP across all corrections. By using the available data, a model was constructed to predict postop IOP change at one month; this was able to explain 42 percent of the IOP change after myopic LASIK, 34 percent of the change after myopic PRK, 25 percent of the change after hyperopic LASIK and 16 percent of the change after hyperopic PRK.
Schallhorn J, Schallhorn S, Ou Y.
Ologen vs. MMC: Wound-healing Modulators in Trabeculectomy
A 12-month retrospective review of outcomes between patients undergoing trabeculectomy with an Ex-PRESS mini glaucoma device using mitomycin-C and those undergoing the same procedure using a subconjunctival collagen matrix device (Ologen) suggests that Ologen provides similar rates of surgical success.
All patients underwent a trabeculectomy using an Ex-PRESS shunt. A total of 49 eyes of 37 patients received Ologen and 50 eyes of 48 patients received MMC. Postoperative data were reviewed over 12 months. Outcomes included mean intraocular pressure, rate of success in achieving target IOP (with and without anti-glaucoma medication), number of medications used and rates of complications/reoperations.
The mean preoperative IOP was 24.98 mmHg for the MMC group and 23.94 mmHg for the Ologen group (p=0.3). At 12 months postop, the mean IOP was 12.1 mmHg for the MMC group and 13.12 mmHg for the Ologen group (p=0.34). At 12 months, the rate of achieving an IOP ≤21 mmHg off medications (unqualified success) was 84 percent for the MMC group and 86 percent for the Ologen group. There was no statistically significant difference between the groups for the rates of achieving a specified postop IOP either with (qualified success) or without medications. There was no statistically significant difference between the two groups in the mean number of postop medications required. Both groups had similar rates of complications and one patient in the MMC group lost light perception after a suprachoroidal hemorrhage.
J Glaucoma 2014;23:649-652.
Johnson M, Sarkisian S.
Choroidal Thickness in Pseudophakic CME
Polish researchers studying the subfoveal choroidal thickness in the acute symptomatic cystoid macular edema patient after uncomplicated cataract surgery, using enhanced depth imaging optical coherence tomography, discovered that the choroid in eyes with CME was thinner than in fellow eyes, suggesting that reduced choroidal blood flow in the choriocapillaris is also a possible factor in CME.
The mean subfoveal choroidal thickness measured in 28 eyes with CME was 229.14 ±62.61 μm and 280.82 ±79.09 μm in fellow eyes. At any point (subfoveal and 1.5 mm nasal; 1.5 mm temporal; 1.5 mm inferior; 1.5 mm superior from the center of the fovea) the choroidal thickness of the affected eye was significantly (p<0.01) thinner than that of the fellow eye.
Odrobina D, Laudanska-Olszewska I.
A Retrospective Analysis of Change in IOP after DSAEK
Researchers have concluded that the occurrence of postoperative IOP elevation is common after Descemet stripping automated endothelial keratoplasty, and that a significant number of patients will need IOP-lowering treatment. Pseudoexfoliation syndrome and PXF glaucoma are serious risk factors for an increased IOP after DSAEK. In most cases, IOP will remain controlled with conservative management, but some patients will require glaucoma surgery.
This study was a retrospective assessment of 211 consecutive DSAEK cases (176 patients), with a minimum one-year follow-up, performed by one surgeon between January 2007 and November 2010. Salient patient characteristics, IOP and type of anti-glaucoma treatment registered in postoperative visits up to 36 months were extracted from patient medical records. IOP elevation and its associations with glaucoma, PXF and a combination of the two were assessed using multivariate ordinal logit models.
Of the 211 eyes, 97 eyes (45 percent) showed at least one increase in IOP >25 mmHg after DSAEK. Of these 97 eyes, 17 eyes (17.5 percent) had a history of glaucoma alone; another 17 eyes (17.5 percent) had a history of glaucoma combined with PXF; 10 eyes (9.7 percent) had PXF alone; and 53 eyes (54.6 percent) were steroid responders only. To control elevated IOP, steroid reduction alone was performed in six eyes (6.2 percent) and IOP-lowering medication as the only measure was performed in 26 eyes (26.8 percent). In 46 eyes (47.4 percent), steroids were reduced in combination with IOP-lowering medication, while 16 eyes (16.5 percent) required surgery. In three eyes (3.1 percent), no action was required. The presence of PXF (odds ratio: 1.71; 95 percent CI, 0.62 to 2.81; p=0.002) and PXF glaucoma (r: 1.14; 95 percent CI, 0.06 to 2.21; p=0.038) required a more intensive IOP-lowering management than patients without PXF with IOP problems.
Müller L, Kaufmann C, Bachmann L, et al.
Aflibercept in Recurrent or Persistent Neovascular AMD
California researchers retrospectively evaluated the six-month and one-year visual and anatomic outcomes of every-eight-weeks intravitreal aflibercept injections in patients with ranibizumab- or bevacizumab-resistant neovascular age-related macular degeneration, finding that more than half of their patients had an excellent anatomic response with injections every eight weeks. However, with longer follow-up to one year, symptoms tended to recur and a third of eyes needed monthly aflibercept injections.
The study cohort consisted of patients with resistance (multiple recurrences or persistent exudation) to every-four-weeks ranibizumab or bevacizumab that were switched to q8w aflibercept. Sixty-three eyes of 58 patients had a median of 13 (interquartile range, seven to 22) previous anti-VEGF injections. At six months after changing to aflibercept, 60.3 percent of eyes were completely dry, which was maintained up to one year. The median maximum retinal thickness improved from 355 μm to 269 μm at six months (p<0.0001) and 248 μm at one year (p<0.0001). There was no significant improvement in visual acuity at six months (p=0.2559) and one year follow-up (p=0.1081) compared with baseline. The mean difference in visual acuity compared to baseline at six months was -0.05 logMAR (+2.5 letters) and 0.04 logMAR at one year (-2 letters).
Am J Ophthalmol 2015;159:426-426.
Arcinue C, Feiyan M, Barteselli G, Sharpsten L, et al.
Genetic Type May Influence Treatment Response to AMD
An analysis of current literature evaluating the pharmacogenetics of treatment response in patients with neovascular age-related macular degeneration suggests that a patient’s genetic background may influence individual response to treatment with anti-VEGF agents. Multiple studies demonstrate associations between various genotypes and response to intravitreal anti-VEGF injections. Lower-risk genotypes of the CFH, ARMS2, HTRA1 and VEGF-A genes may be associated with improved visual outcomes. Additionally, frequency of injections may be associated with certain genotypes.
Dedania V, Grob S, Zhang K, Bakri S.