This year, presentations at ARVO discuss the effects of visual rehabilitation, the likelihood of cataractogenesis in cancer patients due to radiation therapy, and the role that intraocular lenses may play in ensuring patients compliance with a medication regimen.

Each of the following abstracts demonstrates new ways to better your patient care pre- and postoperatively.

Cataract

Zinc in the lens plays a role in cataractogenesis in patients with Alzheimers disease, say researchers in Boston and Berkeley, Calif.5181 And, these zinc deposits are related to the A-beta pathology of Alzheimers disease.

So, a related study posits, a laser utilizing confocal anterior segment scanning ophthalmoscopy, dry optics, single photon detection and fluorescence correlation can be used to find this A-beta pathology through the zinc deposits related to cataract formation.5182 This scanning technology can provide a method of Alzheimers disease detection early enough to allow for possible preventive treatment.

LASIK for Tweens and Teens? LASIK may be an acceptable and successful last resort in the treatment of juvenile patients when conventional therapies fail, report researchers in Goiania, Brazil.3978/A89 In this small study, nine patients with high anisometropia were followed for at least 10 years. Conventional therapy, such as contact lenses, had failed in these cases, and so LASIK was tried as the next option. Ten years after the procedure, Snellen best-corrected acuity was improved by at least one line, and no eyes lost any acuity. Mean preoperative spherical equivalent refraction decreased from -7.66D to -2.33D, mean astigmatism decreased from -3.11D to -0.75D, and mean anisometropia decreased from 7.36D to 1.47D. Four eyes were within one degree of emmetropia, and all patients were able to function binocularly. Researchers note that this study was small, but that results and the extended follow-up demonstrate the procedures safety and efficacy in these cases, especially after conventional therapies had failed.

In patients with cancer who undergo external radiation therapy, cataract formation is a likely postoperative side effect, say researchers in Galveston, Tex., and Houston.5568/D779  The study retrospectively reviewed cases of 58 patients (89 eyes) who underwent various radiation therapieswhole brain, 20; brain stereotactic, 3; total-body irradiation, 13; skull, 4; neck, 5; head and neck, 28; orbital, 16. The group of patients who underwent orbital irradiation demonstrated the worst effects, at a rate of 62.5%: radiation-induced retinopathy, optic neuropathy and posterior capsular haze. Researchers note that a history of external radiation therapy is likely to worsen the patients outcome after the current bout of therapy, and that patients should be counseled as to what they can expect.

During cataract surgery, patients with a shallow anterior chamber (AC) are at significantly more risk for complication, say researchers in Portsmouth, U.K.5578/D789 The data of 8,891 eyes was analyzed, and the AC depth of each eye was noted. Of this cohort, 1,138 eyes had an AC depth of less than 2.5mm, while the AC depth of 7,754 patients was greater than 2.5mm. Overall, complications occurred in 3.56% of procedures. When divided by AC depth, those with a shorter AC experienced a complication 4.75% of the time, vs. 3.4% for those with a deeper AC. Researchers note that AC depth should be calculated into the preoperative risk assessment.

Is visual rehabilitation really worse for patients with traumatic cataract? No, say researchers from Maastricht, Netherlands.5579/D790 In this retrospective study, the cases of 31 patients (29 male, 2 female) were examined for type of trauma, surgical procedure and outcome. Records show that the rehabilitation for each patient was excellent. So, in cases of traumatic cataract, education can play a significant role, and most likely, results for patients with traumatic cataract will be similar to those for patients with senile cataract.

The presence of alpha 1a adrenoreceptors in the iris has led researchers in New York to posit that iris vasculature may serve a structural function, and that intraoperative floppy iris syndrome (IFIS) may develop due to iris vascular dysfunction.5580/D791 IFIS is also associated with Flomax (tamsulosin, Boehringer Ingelheim) and small pupil size. If potential cataract patients are taking tamsulosin, discontinuing the regimen will not affect their changes of developing IFIS, but they can be educated as to the chance of this possible side effect during cataract surgery.

Biodegradable Lens Support? Researchers in Santa Ana and Huntington, Calif., found that a thermally degraded, biodegradable, cross-linked hyaluronic acid scaffold may be able to foster lens regeneration.2086/D898 In this study, rabbits lenses were removed, and the scaffold gel was injected into the capsule to keep it taut. During the next three months, researchers found that this scaffold gel fostered regrowth of the lens. At the conclusion of the study, in the control group (non-thermally degraded hyaluronic acid), only 36.17% of each lens had regrown; but, in the scaffold group, the lenses were completely regrown and spherical, and each demonstrated a clear cortex of good structure.

In a group of patients taking tamsulosin who underwent cataract extraction, researchers found the overall incidence of IFIS to be 29.6%.5584/D795 In this retrospective review, the records of 81 patients were examined. Researchers also examined a subset of these patients who were given intracameral lidocaine/epinephrine (ILE) during the surgery.

Of those who were not given ILE, the incidence of IFIS was 25.4%, but of those who received ILE, the rate was 38.5%. The overall rate that researchers found is lower than previously reported values, they say, but there is a significant association between tamsulosin, small pupils and IFISa very important factor to remember when counseling patients before they undergo a procedure.

Researchers in Sarcelle and Bobigny, France, conducted a retrospective review of more than 1,000 patients who underwent cataract surgery and categorized the ocular comorbidities found within the cohort.5591/D802 Not surprisingly, 51% of patients in the review presented with simple cataractnot affiliated or presenting in conjunction with any other condition. The next-largest group, however, consisted of patients who had diabetic retinopathy: 25%. This condition must be considered prior to surgery, because it presents the potential for delayed wound healing. Early-stage age-related macular degeneration was found in 6% of patientssomething that must be taken into consideration before such procedures as an IOL implantation; the IOL will not be able to negate the effect of the maculopathy. Nearly 6% demonstrated hypertension or glaucomaof these, 3% demonstrated pseudoexfoliation glaucoma, which has the potential to complicate cataract surgery.

Researchers note that the finding of a significant amount of serious comorbidities in a cataract surgery population dictates that the practitioner must be very thorough in the preoperative patient consultation and examinationif the patient undergoes the procedure, he or she may need to be counseled that outcomes may be less than expected.

 

Nutrition

Quercetin may have a positive effect in the prevention of cataracts, found researchers in Norwich, U.K.2084/D896 This nutrient, found naturally in oranges and onions, induced an increase in HIF-1-alpha protein levels in this microarray study. The HIF-1-alpha signaling pathway was activated by the quercetin, resulting in up-regulation of four genes within the pathway. And, this may play a preventive role in cataract formation.

Is the Day After Visit Necessary After Cataract Surgery? Researchers in Maywood and Hines, Ill., question the value of the one-day post-op visit for patients who undergo cataract surgery.5583/D794 Conventionally, follow-up after cataract surgery takes place at one day, one week and one month, but researchers substituted a same-day exam for the day-one exam. In this review, researchers examined the charts of 52 eyes, half of which were examined on the same day, and half of which were examined on day one. They found no significant difference between long-term outcomes in either group, and they noted that patient satisfaction improved with same-day examination. Researchers in Bobigny, France, also question the necessity of the one-day post-op exam.5586/D796 In this prospective study, 103 patients were seen on the first day after their procedure, and the researchers evaluated the healing process and any possible complications. During this examination, 30% of patients demonstrated at least a mild side effect, leading researchers to conclude that, though all patients dont need the visit at day one, it may be beneficial to target patients who are at higher risk of complication.

Caffeine (and other xanthine alkaloids present in many beverages) may actually prevent cataract formation, say researchers in Baltimore.2090/D902 In this in vitro study, the generation of reactive oxygen species that have been shown to cause cataract was induced in lens cultures, which resulted in the expected tissue damage. When caffeine was introduced to the culture, however, it inhibited the damage and protected the cells, leading researchers to hypothesize that it may demonstrate the same action in further studies.

Taking ascorbic acid (vitamin C) prior to phacoemulsification may reduce endothelial cell loss after the procedure, found researchers in Recife, Brazil.2897/A404 In this double-blind, randomized study, 59 patients were randomized to take either vitamin C prior to the surgery or no supplement at all. Following the procedure, the group who took ascorbic acid demonstrated 37.8% less endothelial cell loss than the group who did not. This may help prevent corneal edema post-surgery or lessen the chance that a patient may need an endothelial transplant after the phacoemulsification.

 

Intraocular Lenses

Have you ever seen an IOL implanted, only to find out that the patient requires a postoperative power adjustment? No problemresearchers in Murcia, Spain, evaluated the efficacy, predictability and stability of a light-adjustable IOL that can be adjusted via laser post-implantation.1153/D1115 Two weeks after implantation, the lenses were irradiated to determine if any further adjustments were necessary. Of the 43 patients enrolled, all were treated and accurately controlled. Cases included myopia, defocus, hyperopia and astigmatism. Wavefront aberrations of the eye and the cornea were measured, and the refractive change induced by the IOL was also examined.

Researchers created a refractive profile for each condition and a customized correction within each per patient. Final refractive correction was within 0.25D specificity and modified by 2.00D at most. Most treated patients experienced a 30% improvement from pre-treatment conditions, and patients refractions were stable at six months, at which point the study concluded.

A related study measured higher-order aberrations in the eyes of patients implanted with these light-adjustable IOLs.1626 After the 37 patients underwent lens power adjustment, wavefront aberrations of the eye were measured with a Hartmann-Shack sensor at three and six months after the procedure, and those aberrations in the IOL were calculated. After follow-up, researchers found that the adjustment procedure induced few higher-order aberrationsexcept, notably, in cases of myopic treatment. But, researchers suggest that this procedure points to a future ability to correct and control the eyes aberrations with light-adjustable IOLs.

How Long After Cataract Surgery Should a Patient Get New Glasses? Two weeks is fine, say reearchers in the United Kingdom.5586/D797 Study authors examined 68 patients who underwent uncomplicated phacoemulsification at one week, two weeks and six weeks after the procedure. All operations were carried out by two surgeons who used the same sutureless incision technique. Researchers found that, between two and six weeks postoperatively, there is no significant change in cylindrical refractionthough there is a difference between week one and week two. So, researchers conclude, a patient can be prescribed lenses at two weeks post-op, because it is very unlikely that the patients prescription will change significantly after that.

Several IOLs may serve as effective drug delivery systems, found researchers in Chicago; Sacramento, Calif.; and Rockford, Ill.1154/D1116 They soaked three different IOLsStaar Collamer (Staar), Akreos (Bausch & Lomb) and Acrysof (Alcon)in various antibiotics and calculated their uptake and release times. Researchers found that the specific drug the IOL is soaked in plays a role, as each IOL does not uptake or release all drugs equally, based on the hydrophilic/ hydrophobic properties of the lens and the characteristics of the drug. Each IOL-drug combination must take into consideration the water content and chemical composition of the lens and the molecular size, charge and solubility of the drug, note researchers. Still, this is a promising drug delivery system that could reduce the post-implantation patients need to remember a dosing regimen.

Will an IOL implantation improve the vision of a patient with uveitis? Yes, say researchers in Cambridge, Mass.1155/D1117 In this small retrospective review, records of patients with a history of uveitis who underwent phacoemulsification with posterior chamber multifocal IOL implantation were studied. Follow-up of these 12 patients ranged from five to 22 months. At their final follow-up, 10 eyes had an uncorrected distance acuity of 20/25 or better. One patient needed a second procedure for cortex removal. Postoperatively, nine patients experienced posterior capsule opacification, three experienced cystoid macular edema and two experienced a resurgence of inflammation. Nine eyes underwent an Nd:Yag laser procedure, and acuity improved in all of these. No eye demonstrated glaucoma or retinal detachment, and all patients rated their quality of life as improved post-surgery. Researchers note that the uveitis in such cases must either be well controlled or in remission.

Researchers in Germany hope to improve the bodys foreign body reaction to an IOL by carbon coating it.1161/D1123 In this in vitro study, researchers tested the IOL both coated with nanostructured carbon and unchanged; they measured hydrophobicity, bacterial adhesion and silicone adhesion to mimic conditions in and around the eye. They found that the carbon coat nearly halves the IOLs hydrophobicity, and that bacterial adhesion is decreased from 0.9% to 0.04%. Also, silicone oil adhesion is significantly decreasedfrom 73% to 0.4%. These results, propose researchers, demonstrate that a foreign body reaction to the IOL would be significantly reduced, and that reducing bacterial or silicone adhesion is a promising step.

Researchers in Cleveland demonstrate the effects of trans-scleral sutured IOL implantation in juvenile patients.5575/D786 In this retrospective review, 10 patients who underwent IOL implantation for various reasons were examined. Five of the children had a congenital cataract, three had experieced trauma, one demonstrated persistent fetal vasculature and one was diagnosed with uveitis. After the procedure, five of the 10 eyes demonstrated improved visual acuity, two lost two Snellen lines or less, and the remaining three lost more than two Snellen lines or were finger counting or worse. Also, post-operative complications included retinal detachment (four), glaucoma (two), choroidal hemorrhage (one), cystoid macular edema (one), and failure of penetrating keratoplastyin all, six eyes required retreatment, though there was no IOL dislocation. Even in such a small case series, note researchers, this high rate of postoperative complications suggests that outcomes in a juvenile population would be worse than in adults.   

Presbyopia

With the use of an infrared femtosecond laser, researchers in Mannheim and Heidelberg, Germany, have produced a model to correct for presbyopia.2801/A168 In this finite element model, an intrastromal procedure can be used to perform a customized surgical pattern; the model demonstrates the different corneal biomechanical properties and effects of the procedure. The model also shows that the laser can affect the stroma directly without damaging Bowmans layer or the epithelium. Results demonstrate that the refractive power of the central cornea would be increased, improving near acuity. This procedure would reduce the risk of epithelial ingrowth and lessen pain because there is no flap to consider during recovery.

But, can presbyopia be surgically reversed? Researchers in New York attempted to answer this question, but results werent conclusive.2805/A172 In this small, five-year study, an Erbium laser was applied through a fiber optic probe to create eight radial scleral incisions. The 12 patients involved were then to be followed for five years. At the six-month follow up, 11 patients showed significant improvement in uncorrected near acuity. But, in the years following, the regained diopters of accommodation and near acuity were lost, and by year five, only two patients returned for follow-up. Though the literature suggests the feasibility of the procedure, this study was inconclusive at best.

For the text of each abstract, referenced here by presentation number, please go to www.arvo.org.