American Academy of Ophthalmology Web Site: www.aao.org
New Findings from Ophthalmology, AJO and Archives
May's American Journal of Ophthalmology:
March's Archives of Ophthalmology:
Roundup of Other Journals:
In the largest study to date addressing incision technique and postoperative endophthalmitis (POE), Lundström et al. reviewed all cataract surgeries performed in Sweden from January 2002 to December 2004 and all endophthalmitis cases reported during the same period to the Swedish National Cataract Register.
They detected an increased risk of POE with clear corneal and temporal wounds. However, they noted that the overall rate of POE following cataract surgery is low (0.048 percent, or 109 cases in 225,471 cataract extractions), which they attribute to the widespread use of prophylactic intracameral cefuroxime in Sweden. They calculated that surgeons using the clear corneal or temporal technique would expose one extra patient to POE in 5,000 to 6,000 operations compared with the background rate of one case in 2,400 operations.
An accompanying editorial advises surgeons on interpreting the latest studies on endophthalmitis after surgery.
William Smiddy reviewed age-related macular degeneration studies to quantitate the cost for the visual benefit of various treatment approaches, and then compared them with the costs for treating other retinal conditions.
He found the cost per line of vision saved by AMD therapies ranged from $997 for laser with extrafoveal choroidal neovascularization, to $5,509 for photodynamic therapy with occult lesions and $12,482 for pegaptanib injections. This is in contrast with treatments that range from $651 for retinal detachment repair to $5,458 for diabetic macular edema laser therapy.
The author notes that these costs are further amplified when considering that the life expectancy of the typical patient with AMD is substantially shorter than for many comparison conditions. Based on various assumptions, he also projected that the costs worked out to $9,000 per line of vision for ranibizumab and $600 per line for bevacizumab. With these calculations in mind, the author calls for a cost-containment debate that results in ethically appropriate and politically feasible strategies.
Focusing on the challenge of treating patients with primary open-angle glaucoma and coexisting cataracts, Kobayashi and Kobayashi found no significant difference in intraocular pressure reduction when comparing combined viscocanalostomy and phacoemulsification to combined trabeculectomy and phacoemulsification with mitomycin C.
In this prospective, one-year trial, 40 eyes of 40 patients were randomly assigned to either phacoviscocanalostomy or phacotrabeculectomy with mitomycin C.
The researchers found that there was no significant difference in the mean IOP between the two groups at any point in time. At 12 months, 17 patients (85 percent) in the phacoviscocanalostomy group and 16 patients (80 percent) in the phacotrabeculectomy group achieved an intraocular pressure of less than or equal to 20 mmHg without medication. In addition, there was no significant difference in visual improvement between these two groups.
While the study had key limitations, including its small sample size, the authors conclude that these findings may be clinically valuable when treating patients with primary open-angle glaucoma and cataracts.
Tamsulosin (Flomax) was linked to intraoperative floppy iris syndrome (IFIS) in 2005, and retrospective studies showed that when the surgeon does not anticipate or recognize tamsuolsin-associated IFIS, the rate of posterior capsular rupture and vitreous loss during cataract surgery significantly increases. However, in a prospective observational series of 167 consecutive eyes of 135 patients taking tamsulosin and undergoing cataract surgery, Chang et al. show that being forewarned is being forearmed.
Specifically, when phacoemulsification was performed in conjunction with at least one of four different IFIS management strategies, the rate of posterior capsular rupture and vitreous loss was 0.6 percent, and 95 percent of eyes achieved a BCVA of at least 20/40.
The authors conclude that patients do not need to avoid tamsulosin as long as their ophthalmologist is aware of their medication history.
Lawrence Hirst has found that mitomycin C 0.4 mg/ml eyedrops used four times a day for three weeks is an effective treatment alternative in the early clinical resolution of noninvasive ocular surface squamous neoplasia.
The prospective, randomized, controlled, masked, single-center trial involved 48 consecutive patients diagnosed with biopsy-proven, noninvasive ocular surface squamous neoplasia and randomized to mitomycin C or placebo. After three weeks, none of the 20 patients in the placebo group had resolved clinically, while 24 out of 26 in the mitomycin C group resolved their neoplasia with no complications.
The author warns that this study does not address the recurrence rate after initial resolution and that he plans to address the long-term safety issues once participants reach the five-year follow-up period. In addition, while mitomycin C appears to be the first line treatment of choice for this condition, ophthalmologists should proceed with caution as the drug has been associated with scleral thinning.
American Journal of Ophthalmology
There have been multiple attempts to improve the technique for corneal incision in PK. Buratto et al. evaluated a technique for PK using a new software algorithm for a femtosecond laser.
Seven eyes of seven patients underwent PK surgery using a 15-kHz femtosecond laser and new IntraLase software specifically developed for corneal surgery. In this prospective study, five patients had keratoconus and two had bullous keratopathy. The new software was engineered to create penetrating cuts in a top hat or mushroom configuration. All patients were evaluated with pachymetry, corneal topography, refraction, IOP measurement and corneal optical coherence tomography in the postoperative period.
All eyes had a good appearance on postoperative day one. At three months, all eyes had clear corneas with good endothelial cell counts and quiet anterior chambers. Normal corneal thickness was achieved in each case. At the three-month visit, suture removal was performed in five eyes to adjust for astigmatism.
This pilot study in a small number of eyes indicates that the use of the new IntraLase software for corneal surgery may create a more favorable environment for PK.
Kheirkhah et al. reported on the corneal manifestations in six patients with Demodex infestation of the eyelids.
These six patients with Demodex blepharitis also exhibited corneal surface abnormalities, which were initially suspected to be a limbal stem cell deficiency in three cases. All six patients exhibited ocular irritation and conjunctival inflammation, while five exhibited meibomian gland dysfunction, four exhibited rosacea and three exhibited decreased vision. Prior treatments included oral tetracycline, topical steroids with antibiotics and lid scrub with baby shampoo. Six patients were demonstrated to have Demodex folliculorum and three were demonstrated to have Demodex brevis by microscopic examination of epilated lashes. Their corneal manifestation included superficial corneal vascularization (six eyes of five cases), marginal corneal infiltration (two eyes of two cases), a phlyctenule-like lesion (one eye of one case), superficial corneal opacity (two eyes of two cases) and nodular corneal scar (two eyes of two cases).
All patients received weekly lid scrubs with 50-percent tea tree oil and a daily lid scrub with tea tree shampoo for a minimum of six weeks. All patients showed dramatic resolution of ocular irritation, conjunctival inflammation and all inflammatory, but not scarred, corneal signs. Three patients showed improved vision. After treatment, the Demodex count was reduced.
There were a number of signs similar to or consistent with rosacea in these patients. The authors suggest that when conventional treatments for rosacea fail, microscopic evaluation of epilated eyelids for Demodex infestations, and/or lid scrub with tea tree oil to eradicate mites might be considered.
Ti et al. evaluated the indications, corneal transplantation techniques and therapeutic success for advanced, medically uncontrolled acute infectious keratitis in a consecutive series of 92 patients from 1991 to 2002 who underwent therapeutic keratoplasty at the Singapore National Eye Centre.
Pseudomonas aeruginosa (59 percent) and Fusarium species (32 percent) were the predominant organisms for bacterial and fungal keratitis, respectively. Keratoplasty types included 80 penetrating keratoplasties and 12 lamellar keratoplasties. Mean graft diameter was 9.5 mm. Seventy-four patients (80 percent) achieved therapeutic success after one keratoplasty procedure, and three patients were cured after a second keratoplasty. Life-table survival analysis computed the one-year therapeutic survival for bacterial and fungal keratitis as 77 percent and 72 percent, respectively. The Kaplan-Meier one-year survival rate for penetrating keratoplasty optical clarity was 72 percent. Twenty-two patients underwent repeat keratoplasty: eight for optical reasons, seven for recurrent primary infection and seven for perforation or subsequent new infections. Of the 15 patients for whom therapy failed, 11 had fungal keratitis. Time to recurrence ranged from four days to one year, but most appeared within six weeks after surgery.
Therapeutic keratoplasty is an effective treatment for severe, refractory infectious keratitis. High cure rates are achievable, although recurrence despite prolonged treatment remains a significant problem, especially in fungal keratitis.
The use of prostheses to improve retinal or central nervous system function is an area of active research. Yanai et al. assessed visual task performance in three blind patients implanted with an investigational epiretinal prosthesis.
The three had retinitis pigmentosa with light perception or worse vision in one eye and some visual experience as an adult before blindness. They did not have any other ophthalmic problems.
A prototype retinal prosthesis was implanted in the eye with worse light sensitivity. The prosthesis had a 4 x 4 array of platinum electrodes tacked to the epiretinal surface, and was wirelessly controlled by a computer or by a head-worn video camera. Visual function testing was performed in single- or double-masked fashion. Scores from the visual task were compared to chance to determine statistical significance.
Using the video camera, the patients performed significantly better than chance in 83 percent of the tests. Scores were as follows on simple visual tasks: locate and count objects (77 percent to 100 percent), differentiate three objects (63 percent to 73 percent), determine the orientation of a capital L (50 percent to 77 percent), and differentiate four directions of a moving object (40 percent to 90 percent). A subset of tests compared camera settings using multiple pixels vs. single pixels. Using multipixel settings, subjects performed better than (17 percent) or equivalent to (83 percent) single-pixel settings in accuracy and better than (25 percent) or equivalent to (75 percent) single-pixel settings in reaction time.
In this pilot study retinitis pigmentosa implant patients performed simple visual tasks better with the use of the epiretinal prostheses. The authors found that multipixel settings proved slightly more effective than single-pixel settings.
Archives of Ophthalmology
Saleh et al. utilized the Objective Structured Assessment of Cataract Surgical Skill (OSACSS) tool in a cohort study to evaluate surgical performance during cataract extraction. The instrument was devised following extensive consultation of trainers in the United Kingdom.
Thirty-eight surgeons with different levels of experience in cataract surgery (group A, < 50 surgeries; group B, 50 to 249; group C, 250 to 500; and group D, > 500) performed phacoemulsification cataract extractions. Each surgeon had a complete case recorded. The videos were then randomized and graded with the OSACSS tool by independent assessors masked to the grade of surgeon. OSACSS consists of global rating and task-specific components, each rated on a five-point Likert scale, with a total potential score of 100. The results presented show a statistically significant improvement in the scores of group B over A (P = 0.002), and of group B over C (P = 0.003), but not between groups C and D.
The authors conclude that OSACSS was able to differentiate between surgeons of different grades and thus may be of value when assessing cataract surgery in junior trainees.
Kuppermann et al. evaluated the safety and efficacy of a single treatment with a dexamethasone intravitreous drug delivery system (dexamethasone DDS) in patients with macular edema that had persisted for at least 90 days despite laser treatment or medical therapy.
Three hundred and fifteen patients with persistent macular edema were randomized to observation or a single treatment with dexamethasone DDS 350 µg or 700 µg. Patients were followed for 180 days. The main outcome measures were the proportion of patients achieving ≥10- or ≥ 15-letter improvements in BCVA, changes in fluorescein angiographic leakage and central retinal thickness, and safety measures.
At day 90, improvements in BCVA of ≥ 10 letters were achieved by a greater proportion of patients in the dexamethasone treatment groups (35 percent in the 700 µg group and 24 percent in the 350 µg group) than in the observation group (13 percent, with a P < 0.001 when compared with the 700 µg group, and 0.043 compared with the 350 µg group). Improvements in BCVA of ≥ 15 letters were achieved in 18 percent of 700 µg patients vs. 6 percent of observed patients (P = 0.006).
Statistically significant improvements in central retinal thickness and fluorescein leakage were also seen in the 700 µg group at day 90. Dexamethasone was well-tolerated through 180 days post-treatment. Over three months, 11 percent of treated patients and 2 percent of observed patients had IOP increases ≥ 10 mmHg.
The authors conclude that a single dexamethasone DDS treatment was well-tolerated and produced statistically significant BCVA improvements in patients with persistent macular edema.
Elner et al. examined the efficacy of transcaruncular medial canthal ligament plication for treating symptomatic ocular exposure secondary to lower eyelid malposition in which medial canthal ligament laxity was an important component.
One hundred and seventy-six eyelids of 125 patients were treated with transcaruncular medial canthal ligament plication with a transconjunctival approach anchoring the tarsus to the medial orbital wall. Other concurrent repairs included lateral canthal ligament plication, midfacial lift, reinsertion of lower eyelid retractors, hard-palate grafting and lateral tarsorrhaphy. Preoperative and postoperative symptoms and signs were compared with an average follow-up of more than two years.
Preoperative symptoms of tearing, discomfort and lower eyelid malposition resolved in 81 percent of eyes and improved in 7 percent of eyes. Medial canthal laxity was successfully treated in more than 92 percent of eyelids. Signs of superficial punctate keratopathy, lower eyelid retraction and lagophthalmos improved in 72 percent, 94 percent and 75 percent of eyes, respectively. In all cases, postoperative results were highly statistically significant (P < 0.001), and no complications occurred.
The authors conclude that transcaruncular medial canthal ligament plication is a safe and effective technique for medial canthal ligament laxity that contributes to lower eyelid malposition. This minimally invasive technique achieves good functional and cosmetic outcomes by reestablishing the three-dimensional lower eyelid support normally provided by the ligament.
High-pressure secondary glaucoma is known to cause reduced acuity, contracted visual fields and generalized optic atrophy without glaucomatous cupping. A histopathologic study by Knox et al. of 12 such enucleated human eyes found anatomic explanations for the above clinical features.
Hydropic axonal degeneration was seen in the lamina cribrosa or retrolaminar optic nerve in all 12 eyes. Blocked retrograde axoplasmic transport was seen in nine eyes. Nerve bundle atrophy with glial cell hyperplasia and disorganization was seen in 10 eyes. These three types of changes were seen in the optic nerve centrally, nasally and diffusely, but not primarily temporally. No eye had glaucomatous cupping.
These findings indicate that the primary pathophysiology of this type of glaucoma is located in or near the lamina cribrosa. Eyes with early chronic simple glaucoma should be studied for the same changes.
Sakata et al. compared the ability of frequency doubling perimetry (FDP-Matrix) with standard automated perimetry-Swedish Interactive Threshold Algorithm (SAP-SITA) in detecting visual field abnormalities in patients with glaucomatous-appearing optic discs (GAOD).
This observational case study included 80 patients with GAOD and 54 control subjects diagnosed by masked assessment of optic disc stereoscopic photographs. Abnormal visual function with SAP-SITA and FDP-Matrix testing required consistent abnormalities in two visual field examinations determined by using the glaucoma hemifield test outside 99 percent normal limits, pattern standard deviation outside 95 percent normal limits or three contiguous points in the pattern deviation probability plot outside 95 percent normal limits (at least one, P < 1 percent).
The FDP-Matrix and SAP-SITA respectively detected abnormal visual function in 51 percent and 44 percent of GAOD eyes (P = 0.26), and both techniques identified 11 percent of control eyes as abnormal. Agreement between FDP-Matrix/SAP-SITA was moderate (kappa = 0.49), as only 35 percent of GAOD and 2 percent of healthy eyes had abnormalities in both visual field tests.
The authors conclude that FDP-Matrix detected abnormal visual function in more eyes with GAOD than did SAP-SITA, although this difference was not significant. Each visual field test tended to identify different subsets of GAOD eyes as abnormal. A combination of these perimetry techniques may improve the detection of visual function abnormalities in patients with glaucoma.
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.
A prospective study by Costa et al. of seven eyes of seven patients with macular edema associated with ischemic central or hemicentral retinal vein occlusion treated with intravitreal bevacizumab showed promising short-term results.
Patients received 2-mg injections of this anti-VEGF neutralizing antibody at 12-week intervals. Six patients completed the 25-week follow-up examination with reinjections performed at weeks 12 and 24. At baseline, mean BCVA was 1.21 (approximately 20/320), in contrast with the last follow-up, when the mean BCVA in the affected eye was 0.68 (approximately 20/100). No patient had a decrease in BCVA, and dye leakage within the macula and affected retinal quadrants shown by fluorescein angiography was noticeably reduced. However, optical coherence tomography indicated a macular edema recurrence between the sixth and twelfth weeks after injection, suggesting that the effect may not be long lasting, and repeat injections might be needed.
Based on the evidence of BCVA stabilization or improvement, and favorable macular changes, the authors call for further studies to help establish whether there is a role for antiangiogenic therapy in the management of retinal vein occlusions.
Nayak et al. previously reported that antipericyte autoantibodies (APAAs) are evident in high frequencies in the sera of diabetic patients with and without proliferative retinopathy. The researchers conducted this new study to determine whether progression of retinopathy in type 2 diabetic patients was associated with the same pattern of medical risk factors in APAA-negative patients as in APAA-positive patients. This prospective analysis involved 186 type 2 diabetics with nonproliferative retinopathy at baseline who were followed for two years. Thirty-eight demonstrated progression of retinopathy in at least one eye.
The investigators found that progression of retinopathy was associated with HbA1c level, duration of diabetes and albumin/creatinine ratio in APAA-negative patients but not in APAA-positive individuals. This association proved strongest in the upper quartile for HbA1c level, in which 71.4 percent of patients negative for APAAs had progression of retinopathy. Only 24.1 percent of APAA-positive patients showed progression.
The authors conclude that further validation is needed to determine whether APAAs play a regulatory role in mechanisms responsible for the progression of diabetic retinopathy.
While phacoemulsification cataract extraction and IOL implantation in patients with uveitis seems to be well-tolerated, those with Behçet’s disease appear to have a higher risk for complications, and therefore worse outcomes, according to a study by Kawaguchi et al. The investigators retrospectively reviewed records of 95 patients (131 eyes) with uveitis who had undergone phacoemulsification cataract extraction and IOL implantation between 1990 and 2001.
Overall, 111 eyes (84.7 percent) had improved visual acuity after the procedure, and 97 eyes (74 percent) had a final visual acuity of 0.5 or better. Individuals with Behçet’s disease experienced significantly worse visual outcomes and increased episodes of recurrent inflammation six months after surgery. However, due to prompt treatment, most achieved good visual outcomes. Other complications included elevated IOP (8.1 percent), cystoid macular edema (6.1 percent), posterior synechiae formation (6.1 percent) and posterior capsular opacification needing capsulotomy (23.7 percent).
The authors conclude that surgeons should choose their cataract patients with caution, especially those with Behçet’s disease, and carefully control preoperative and postoperative inflammation.
A longitudinal study of IOL exchange indicates that the procedure is relatively safe and effective with an excellent chance for improved vision. Marques et al. conducted a retrospective study of 49 eyes of 49 adult patients who underwent IOL exchange between 1986 and 2002 by the same surgeon at the Cincinnati Eye Institute in Ohio. These patients were divided into two groups—anterior chamber (AC, 15 eyes) and posterior chamber (PC, 34 eyes)—according to the IOL originally implanted.
In the AC-IOL group, the main indication for IOL exchange was inflammation. In the PC-IOL group, the indication was decentration/dislocation. In addition, the interval between the first surgery and IOL exchange was longer in the AC-IOL group (82.3 months vs. 37.9 months). BCVA after the exchange was similar in the two groups, and better than or equal to preoperative levels in 80 percent of cases.
Roundup of Other Journals is written by Lori Baker Schena and edited by Deepak P. Edward, MD.