American Academy of Ophthalmology Web Site: www.aao.org
New Findings from Ophthalmology, AJO and Archives
• Intacs Effective in Post-LASIK Corneal Ectasia
• Recurrence of Amblyopia After Occlusion Therapy
• Pars Plana Vitrectomy vs. Combined Vitrectomy–Scleral Buckle
• Bimatoprost-Induced Skin Hyperpigmentation in Caucasians
• Risk of Retinal Detachment After Cataract Extraction
Roundup of Other Journals:
A study by Kymionis et al. indicates that Intacs inserts are effective in the long-term (five years) management of post-LASIK corneal ectasia. The researchers followed three men and two women (eight eyes) aged 31 to 54 with post-LASIK corneal ectasia who had Intacs segments inserted nasally and temporally, with thickness based on the residual refraction of the patients. At the five-year follow-up, all patients maintained refractive stability, with no evidence of progressive time-dependent corneal ectasia, late regression or sight-threatening complications. Pre-Intacs uncorrected visual acuity was 20/100 or worse in all eyes, while at the five-year follow-up, six of the eight eyes had uncorrected visual acuity of 20/40 or better. While the study involved only five patients, the authors note that Intacs may represent a viable, minimally invasive treatment alternative for patients with post-LASIK corneal ectasia. However, final conclusions about this surgical technique can only be made after further follow-up.
Bhola et al. have found a clinically significant risk of a recurrent amblyopia in patients with anisometropia or strabismus when maximal occlusion therapy is decreased before age 10.
Over a 34-year period, the investigators reviewed charts of 449 patients younger than 10 years old who were treated by occlusion therapy for strabismic and/or anisometropic amblyopia. They defined an amblyopia recurrence as two or more logMAR levels of visual acuity reduction or reversal of fixation preference within one year after a decrease or cessation of occlusion therapy. The researchers reported that of 653 occlusion trials, 179 (27 percent) resulted in recurrence of amblyopia. Age constituted a significant risk factor for the recurrence of amblyopia, and there was an inverse correlation of age with recurrence.
They conclude that these findings may serve as useful guidelines for physicians and patients when deciding the optimal time to withdraw occlusion therapy in children under age 10.
In a retrospective study, Weichel et al. determined that pars plana vitrectomy (PPV) is as effective as a combined pars plana vitrectomy–scleral buckle (PPV–SB) to repair noncomplex pseudophakic retinal detachments.
The study included 68 patients who underwent PPV and 84 who underwent PPV–SB between 2002 and 2004.
All primary PPV cases were done by two surgeons who perform vitrectomy without regard to location of detachment, number or location of break(s), refractive error or macular status.
All primary PPV–SB techniques were done by a group of surgeons who solely perform this operation on pseudophakic retinal detachments.
The study revealed that the overall single surgery success rate in the PPV– SB group was superior by 1.4 percent. Unfortunately, the postoperative complication rate was 13 percent higher.
The PPV group demonstrated a one-line improvement in overall Snellen visual acuity.
The authors of this retrospective study conclude that the anatomic and visual outcomes of either a PPV or PPV–SB were equally efficacious and may offer advantages over alternative methods for repairing pseudophakic retinal detachments.
Doshi et al. report the clinical characteristics and time course of appearance and resolution of periocular bimatoprost-induced skin hyperpigmentation in Caucasians. The retrospective, noncomparative case series involved 29 female and eight male Caucasian patients who developed cosmetically noticeable periocular skin hyperpigmentation after starting bimatoprost therapy. An unbiased examiner conducted a retrospective chart analysis of these patients, grading the periocular hyperpigmentation using an arbitrary scale from 0 to 3+. The researchers found that the bimatoprost-induced periocular hyperpigmentation was mainly mild and appeared most frequently between three and six months after initiating bimatoprost therapy. However, there was a wide range in the time period the hyperpigmentation was first noted. Additionally, they discovered that discontinuation of bimatoprost resulted in gradual and complete reversal of the periocular skin hyperpigmentation in most patients, with the majority experiencing complete resolution between three and six months after stopping the medication. The authors conclude that the nature of bimatoprost-induced hyperpigmentation is benign and reversible.
Using data from the Rochester Epidemiology Project that encompasses residents of Rochester and surrounding Olmsted County, Minn., Erie et al. demonstrate that the risk of retinal detachment (RD) after extracapsular cataract extraction (ECCE) and phacoemulsification increased in a nearly linear manner within a 25-year period.
The population-based cohort study included 10,256 cataract extractions performed on 7,137 Olmsted County residents of all ages. Two controls chosen from the primary cataract surgery cohort were matched to each RD case by age, sex and duration of follow-up. The researchers identified 82 cases of RD. At one, five, 10, 15 and 20 years after ECCE and phacoemulsification, the cumulative probability of RD was 0.27 percent, 0.71 percent, 1.23 percent, 1.58 percent and 1.79 percent. Male gender, younger age, myopia, increased axial length and posterior capsular tear were significantly associated with RD.
These findings underscore the need for full preoperative explanation of the long-term risk of pseudophakic RD, especially in the higher-risk subgroups.
Avery et al. saw a “dramatic and rapid response” using intravitreal bevacizumab injections to treat retinal and iris neovascularization secondary to proliferative diabetic retinopathy (PDR), with complete resolution of the vascular leakage in most cases.
The study was prompted by initial reports demonstrating the effectiveness of bevacizumab in treating age-related macular degeneration. In this interventional, retrospective case series, 45 eyes of 32 patients received intravitreal bevacizumab (6.2 µg to 1.25 mg). Short-term results indicated that the treatment was well-tolerated. Fluorescein angiography demonstrated that all patients with neovascularization had complete or at least partial reduction in leakage of the neovascularization within one week following injection, with complete resolution observed in 19 eyes. The investigators observed a consistent biological effect, even with the lowest dose, as well as a possible therapeutic effect in the fellow eye.
They call for prospective clinical trials to explore safety, dosing, efficacy and duration of effect of bevacizumab to treat PDR.
Results from a pilot study by Chun et al. evaluating multiple intravitreal injections of ranibizumab in patients with center-involving, clinically significant DME indicate the treatment is well-tolerated and can potentially maintain or improve BCVA.
Ten patients (10 eyes) received three intravitreal injections of ranibizumab (0.3 mg or 0.5 mg each injection) on day 0, month 1 and month 2. Results indicate that ranibizumab treatment was well-tolerated, with five cases of mild to moderate, manageable intraocular inflammation. Overall, visual acuity improved in the study eye for both the low-dose and high-dose groups at three months, although the gains tended to diminish from the third-month to the sixth-month visit in both groups. Central retinal thickness decreased in the study eye for both the groups at three months relative to baseline.
Further studies will assess the safety and efficacy of this treatment, and may help clarify the dose-related differences in visual acuity.
A meta-analysis by Arya et al. of published literature from 1966 to 2004 regarding surgical treatment of uncomplicated pseudophakic retinal detachments (RDs) indicates pars plana vitrectomy (PPV), with or without a scleral buckle (SB), is more likely to result in a positive anatomical and visual outcome than is conventional scleral buckle alone.
For this study, the researchers compared reattachment and functional success rates after PPV, SB and a combination of the two procedures, reviewing 1,232 articles focusing on surgical interventions for uncomplicated pseudophakic RDs. The likelihood of retinal reattachment after PPV or the combined method is higher relative to SB alone, a finding the investigators say to better localization of peripheral breaks and a greater release of traction during PPV.
While the literature confirms that current surgical treatment methods for RDs are effective, the researchers caution these findings should be viewed in light of the inherent limitations of a meta-analysis including dissimilar study protocols and varying quality of the published studies.
Previous studies have shown erythrocyte sedimentation rate (ESR) and C-reactive protein (CPR) strongly correlate with a positive temporal artery biopsy in patients with suspected giant cell arteritis (GCA).
Most patients with GCA have both an elevated ESR and CRP; sometimes the CRP can be elevated when the ESR is normal. Parikh et al. wondered if the CRP can be normal when the ESR is elevated in biopsy-proven GCA, or whether this finding indicates another diagnosis altogether. To test this hypothesis, they retrospectively reviewed medical records of 119 patients with biopsy-positive GCA from six major centers who underwent pretreatment ESR and CRP assays. Two patients (1.7 percent) with biopsy-proven GCA had a normal pretreatment CRP despite an elevated pretreatment ESR. While this combination of an elevated ESR and normal CRP is rare, it is not inconsistent with GCA.
The authors conclude that both tests provide a slightly greater diagnostic sensitivity for GCA than either test alone.
In the long term, what effect do larger ablation zones have on refractive stability and corneal transparency following photorefractive keratectomy?
Results from a prospective follow-up study by Rajan et al. involving 123 eyes treated between 1990 and 1993 and examined 10 to 12 years later found that patients with larger ablation zones did, in fact, achieve refractive stability and better outcomes. At the time of treatment, Summit Technology UV 200 and Omnimed Excimer lasers were used to perform PRK with either 4-mm, 5-mm or 6-mm optical zones. Patients received either –3 D or –6 D myopic spherical corrections.
All three ablation groups experienced excellent refractive stability in the long term. In addition, the researchers observed a significant linear trend in terms of better refractive predictability, decreased early hyperopic shift, lesser regression, reduced night vision haloes and corneal clarity preservation with the larger ablation zones. None of the eyes had sight-threatening complications.
These findings confirm the long-term safety of PRK using larger ablation zones.
Multiple automated machines are being used to evaluate optic disc damage. Barkana et al. assessed the interchangeability of optic disc size measurements using slit-lamp funduscopy, optical coherence tomography (OCT-3) and confocal scanning laser ophthalmoscopy (HRT-II) in clinical practice.
Measurements of vertical disc diameter (VDD) were obtained with these three methods in a prospective, nonrandomized clinical study. Disc area was obtained from OCT and HRT printouts. True agreement between methods in measuring VDD was assessed using Bland-Altman graphs and 95 percent limits of agreement (LoA). Discs were classified as small, average or large, and agreement between methods in this classification was assessed using five statistics.
Forty-eight patients were enrolled (mean age 53.4). VDD was 1.58, 1.7 and 1.9 mm with funduscopy, HRT and OCT, respectively. Very large LoA were observed. There was poor agreement in classification of disc size as small, average or large whether disc diameter or area was compared and using either definition of disc size.
The large range of differences in estimating disc size with funduscopy, HRT and OCT may preclude interchangeable use of these measurements in clinical practice. There are not adequate simple conversion formulas. There is also poor agreement between these methods in classifying disc size as small, average or large. It appears that estimation of both absolute and relative disc size can only be defined separately for each measurement modality.
Ng et al. assessed the agreement between structural and functional testing in classifying eyes as normal or abnormal and also assessed their repeatability on two consecutive visits by means of standard automated perimetry (SAP) and confocal scanning laser ophthalmoscopy.
One hundred and fifty-one participants with SAP and Heidelberg Retina Tomograph (HRT) tests at two visits within 15 months were included. Eyes were classified by SAP and HRT at each visit. Agreement and repeatability were assessed by five statistics. At visit 1, 33 (22 percent) of 151 eyes had only SAP defects, 11 (7 percent) eyes had only HRT defects and 35 (23 percent) eyes had both SAP and HRT defects. Seventy-two eyes (48 percent) were classified as normal by both tests. Similar results were obtained for visit 2. The agreement between SAP and HRT in classifying eyes was 70 percent at visit 1 and 68 percent at visit 2. Repeatability of classification by SAP alone, HRT alone, and both SAP and HRT between visits 1 and 2 was 84 percent, 89 percent and 90 percent, respectively.
The agreement between SAP and HRT was only fair at both visits. Repeatability across visits was substantial for SAP alone, HRT alone, and for the combination of SAP and HRT.
These results suggest that detection of particular features of glaucomatous damage depends on the technique used. Structural and functional tests appear complementary, and both should be used for early detection of glaucoma.
Floyd et al. from Salt Lake City studied heat generation, vacuum and flow characteristics of the Alcon Infiniti and Bausch & Lomb Millennium. They compared these results with the Alcon Legacy and AMO Sovereign machines.
Heat generation with continuous ultrasound was determined with and without a 200-g weight. Flow and vacuum were determined from 12 to 40-ml/ min in 2-ml/min steps. The impact of Staar Cruise Control was also tested. Millennium created the most heat at 20 percent of power, followed by Sovereign, Infiniti and Legacy. Flow studies revealed that Millennium Peristaltic was 17 percent less than indicated, and all other machines were within 3.5 percent of indicated. Cruise Control decreased flow by 4.1 percent. Millennium Venturi had the greatest vacuum, and Cruise Control increased vacuum in a peristaltic machine 35 percent more than the Venturi system.
The authors conclude that percent power is not consistent in regard to heat generation; however, flow was accurate for all machines except Millennium Peristaltic. Restriction with Cruise Control elevates unoccluded vacuum to levels greater than the Venturi system tested.
Herpes zoster ophthalmicus (HZO) is uncommon in children, and there is limited information regarding ocular complications of the disease in children.
DeFreitas et al. evaluated the complications of HZO in 10 healthy patients (five boys and five girls) in a prospective, observational case series. Data regarding BCVA, biomicroscopy, IOP, corneal sensitivity and funduscopy were collected. The median duration of follow-up was 19 months. The mean age at presentation was 8.7 years. At last visit, two patients had decreased visual acuity, and nine had some degree of abnormal corneal sensitivity and corneal opacity despite good final visual acuity.
In general, HZO seems to have a good prognosis in healthy children; nonetheless, some cases can present severe eye complications causing visual loss.
Mahadevia et al. examined the effectiveness of the Medicare Prescription Drug Card program for patients with glaucoma. The Drug Card program, which was terminated with the introduction of Medicare Part D in January 2006, was established to provide Medicare subscribers with some relief from the burden of paying for their prescription medications.
The authors compared the prices of all commonly used topical glaucoma medications available to residents of California, New York, Florida and Wyoming through the Drug Card program, as well as through retail pharmacies in their area and the discount Web site www.drugstore.com.
The authors found that, on average, prices were comparable for the Drug Card program and the discount Web site, but that the retail pharmacies were more expensive. They conclude that, for most seniors, shopping at an online discount site would have been easier and as economical as using a prescription drug card.
Regardless of the method of purchasing glaucoma medications, however, out-of-pocket costs remained substantial.
Brauner et al. examined the course of glaucoma during pregnancy in women with preexisting disease in a retrospective case series.
The medical records of 15 women (28 eyes) with glaucoma who were followed by the authors during pregnancy were examined. The patients’ data were analyzed for age, race/ethnicity, medications, glaucoma type, intraocular pressure and visual fields before, during and after pregnancy.
Fifty-seven percent of eyes in the study had stable IOP and no progression of visual field loss during pregnancy. Eighteen percent of eyes experienced visual field loss progression in the setting of stable or increased IOP. Eighteen percent of eyes had increased IOP during pregnancy, with no progression of visual field loss. And seven percent of eyes had inconclusive data due to medication noncompliance or preexisting severe visual field loss.
Ocular hypotensive medications were used by 13 of 15 women in the study to control glaucoma during pregnancy. The most frequently used medications were beta-blockers, alpha2-drenergic agents, cholinergic agents and topical carbonic anhydrase inhibitors.
The authors conclude that the course of glaucoma during pregnancy is variable, and women with preexisting disease should be monitored closely. Medications may be necessary to control IOP and to prevent vision loss, and should be prescribed in collaboration with obstetricians to ensure the safety of the mother and the fetus.
Savini et al. evaluated the ability of optical coherence tomography (Stratus OCT) to measure retinal nerve fiber layer thickness in 12 eyes of nine patients with optic disc edema due to anterior ischemic optic neuropathy, multiple sclerosis-associated papillitis or papilledema.
Patient follow-up ranged between eight and 30 weeks.
OCT could detect and quantify RNFL thickening during the acute course of disease. The instrument identified a hyporeflective space between the RNFL and the retinal pigment epithelium. The clinical and pathogenetic significance of such a space remains to be explained. As the diseases evolved toward atrophy or clinical resolution, OCT identified the progressive thinning of the RNFL.
The authors conclude that OCT may be helpful in detecting, characterizing and monitoring RNFL swelling in the case of optic disc edema. Quantification of RNFL edema using this technology may provide a useful objective index for following the clinical course of these diseases.
In addition, in vivo imaging by OCT may help elucidate the pathogenesis of optic disc edema in general and these optic neuropathies in particular. The information acquired would be complementary to the data obtained from histopathologic studies, in which collection of large samples is difficult and longitudinal observations are impossible.
Ophthalmology summaries are written by Lori Baker Schena and edited by John Kerrison, MD. American Journal of Ophthalmology summaries are edited by Thomas J. Liesegang, MD. Archives of Ophthalmology summaries are written by the lead authors.
Roundup of Other Journals
Bhor et al. report an unprecedented outbreak of Fusarium keratitis among contact lens wearers in Singapore.
In this hospital-based case series, 66 patients (68 eyes) were diagnosed with Fusarium keratitis from March 2005 through May 2006, translating to an estimated annual national incidence of 2.35 cases per 10,000 contact lens wearers. Sixty-five patients (98.5 percent) wore soft, disposable contact lenses, and 62 patients (93.9 percent) used one brand of contact lens cleaning solution (ReNu With MoistureLoc, manufactured by Bausch & Lomb). A majority of patients had poor contact lens hygiene practices, including overnight use of daily wear contact lenses and the use of contact lenses past the replacement date. BCVA ranged from 20/20 to 20/80, with five patients undergoing emergency therapeutic or tectonic corneal transplantation. The authors report that Bausch & Lomb, in a letter to the American Academy of Ophthalmology, acknowledged that under extreme conditions, such as when the solution is allowed to evaporate or is not regularly replaced in the case, “the concentration of polymers included in the formula to enhance comfort may make the solution more likely to be contaminated with Fusarium in the environment.”
The researchers encourage eye care providers to consider the possibility of fungal infection when treating patients for contact lens–associated microbial keratitis.
Is there an association between optic neuritis and receipt of anthrax vaccine among members of the U.S. military?
A matched case-control study by Payne et al. conducted among U.S. military personnel from 1998 through 2003, could find no evidence supporting this hypothesis. Additionally, the researchers could not identify any statistically significant associations between optic neuritis and prior receipt of smallpox, hepatitis B or influenza vaccinations. The researchers matched each optic neuritis case (1,131 total) to three controls (3,393 total) based on sex, deployment during the 18 weeks preceding the diagnosis date, and the military unit in which the individual served (for example, active or reserve/National Guard). No statistically significant associations between optic neuritis and the anthrax vaccine were observed at the six-week, 12-week or 18-week intervals. In addition, the researchers found no difference in optic neuritis risk when comparing individuals who received no dose, one dose or two doses of anthrax vaccine.
They conclude that these negative findings add to the evidence related to current debate regarding vaccine safety, specifically the safety of anthrax, smallpox, hepatitis B and influenza vaccinations.
New findings by Klein et al. from The Beaver Dam Eye Study, an observational, longitudinal, population-based study started in 1987 in Wisconsin, indicate that statin use in the general population may be associated with a lower risk of nuclear cataract. However, this relationship was not found in cortical or posterior subcapsular cataracts.
In this subset of the original study participants, 1,299 persons with gradable photographs in both eyes were identified between 1998 and 2000 as at probable risk for developing nuclear cataract. In the period between 1998 and 2005, 210 persons developed nuclear cataract. The five-year incidence of nuclear cataract was 12.2 percent in statin users compared with 17.2 percent in nonusers. Simvastatin and atorvastatin were the most commonly used statins, followed by pravastatin, fluvastatin and lovastatin. The researchers explain that while the sample size is small, the phenomenon can be explained biologically since statins reportedly counter oxidative stress and inflammation, two factors related to nuclear cataract.
They call for both further study of their own cohort and more large-scale studies to determine the relationship between statin use and cataract.
Kharod et al. describe a number of findings from a study looking at the effect of written instructions on the accuracy of self-reporting medication regimens in glaucoma patients.
Eighty-five women and 79 men with a mean age of 68 years completed both phases of the study, which involved participating in oral confidential questionnaires and a take-home written chart to describe their ophthalmic medications, frequency and dosage. Eighty-four patients did not complete high school, and 80 were high school graduates. Results indicated that patients who did not complete high school were less likely to accurately self-report their medication regimens than those who did graduate from high school. In addition, patients who took fewer medications were more likely to accurately recall their medication regimen. But medication reporting accuracy actually improved in all patients after they received written instructions, with those on three or four medications benefiting more from the written instructions than those taking one or two medications.
The authors conclude that written instructions are a simple and inexpensive method to help glaucoma patients with compliance, especially those with lower education levels and those taking multiple medications.
In a study of residents in rural South India, Raju et al. found a significant association between tobacco use and cataract, particularly smokeless tobacco.
As background, the authors noted that approximately one-third of all women and two-thirds of men in India use tobacco, either smoking tobacco, tobacco in the form of snuff or chewing tobacco. Of the 3,924 participants from the Chennai glaucoma project who were included in this study, 1,705 persons used tobacco and were older than nonusers (55.8 years vs. 52.2 years). While smoking was not found to be significantly associated with cataract, even after adjusting for age and gender, smokeless tobacco use was significantly associated with cataract, a significance that remained even after adjusting for age and gender. Of the smokers, the majority of them smoked bidis, which burn less efficiently than cigarettes. This may explain the lack of association of smoking with cataract in this population.
They conclude that the hazards of smokeless tobacco use is not well-publicized in rural populations, and thus an effective antitobacco program may help reduce tobacco-related ailments, especially among the younger generation.
Small pupil size poses its own set of challenges during phacoemulsification, including possible capsule rupture and vitreous loss. Shingleton et al. present a retrospective analysis of 115 eyes in which a pupil stretch was performed during phacoemulsification.
For this study, the same surgeon used a Kuglen hook and Y-hook to stretch the pupil in the 3 to 9 meridian and then in the 12 to 6 meridian. Using a control group of 125 eyes without pupil stretch, the researchers analyzed the two sets of patients for at least 12 months. They found no statistically significant difference at one-year follow-up in BCVA or IOP. In addition, no significant difference was found in the number of glaucoma medications required for glaucoma patients preoperatively and postoperatively between the two groups. Nor were there significant differences in the complications, which were rare, and no cases of cystoid macular edema.
The authors conclude that pupil stretch techniques can be used safely during phacoemulsification to enhance surgeon visualization and improve outcomes in patients with miotic pupils.
In a “Brief Communications,” Moslehi et al. focus on the rapidly increasing incidence of ocular adnexal non-Hodgkin’s lymphoma (NHL). Specifically, they discuss a recent report that this condition may be related to Chlamydia psittaci infection, a finding that prompts the need for “reliable epidemiologic data for this malignancy.”
To learn more, the researchers examined population-based incidence data from the Surveillance, Epidemiology, and End Results (SEER) Program. Statistics from 1992 to 2001 showed highest incidence rates of ocular NHL in Asian/Pacific Islanders, with lower rates in whites and still lower rates in blacks. However, from 1975 to 2001, there was a rapid and steady increase in incidence of ocular NHL, with annual increases of 6.2 percent and 6.5 percent among white males and white females, respectively, with no evidence of peaking.
The authors hypothesize that C. psittaci infection, which is caused by exposure to infected birds and pets, may account for these incidence patterns. They call for further studies to explore the role this and other infections may play in ocular NHL.
Roundup of Other Journals is written by Lori Baker Schena and edited by Deepak P. Edward, MD.