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New Findings from Ophthalmology, AJO and Archives
 
 

Bilateral Glaucoma: Results of Uniocular Drug Trials and IOP Response of Second Eye

In Keratoconus Patients, Half of Normal Fellow Eyes Will Be Diseased Within 16 Years

Topical Cyclosporin A Safe for Topical Steroid-Resistant Atopic Keratoconjunctivitis

Uveitis Is More Prevalent Than Previously Thought

Endoscopically Assisted Balloon Dacryoplasty for Incomplete Nasolacrimal Duct Obstruction

How Do Intraoperative Epithelial Defects Affect LASIK Outcomes?

Monitoring Changes in Liver Function Tests Can Help Predict Metastatic Uveal Melanoma

The Confocal Scanning Laser Ophthalmoscopy Study

Cataract Progression Following Vitrectomy for Macular Holes and Epiretinal Membranes

Informed Consent and Decision Making in Cataract Surgery

A Randomized, Prospective Trial Compares LASEK With PRK

Central Corneal Thickness and Advanced Glaucoma Damage

Dacryocystorhinostomy May Be Safely Completed Through a Retrocaruncular Approach

Prognostic Factors in Pediatric Pilocytic Astrocytomas


Previews

Bilateral Glaucoma: Results of Uniocular Drug Trials and IOP Response of Second Eye

March’s Ophthalmology

Realini et al. have found that uniocular drug trials in individuals with glaucoma do not predict second-eye IOP reductions following treatment with the same medication.

Fifty-two patients with bilateral glaucoma underwent uniocular trials of various glaucoma medications, and then subsequently received the same drug in the fellow eye. Results showed that while the IOP dropped a mean of 5.7 + 3.8 mmHg in the first eye after a uniocular trial, it dropped a mean of 2.8 + 3.3 mmHg in the second eye after bilateral use. Regression analysis indicated a poor correlation between first-eye and second-eye response to the same medication.

To confirm these findings, the researchers treated a subset of 26 patients with latanoprost (Xalatan), which has little contralateral IOP effect due to rapid systemic metabolism. No improvement in correlation was seen.

The researchers conclude that uniocular trials are not likely to be helpful in glaucoma management because they do not adequately predict second-eye IOP response to the same medication. Instead, the effect of a given medication must be assessed independently for each eye.

In Keratoconus Patients, Half of Normal Fellow Eyes Will Be Diseased Within 16 Years
March’s Ophthalmology


In a longitudinal study of normal eyes in unilateral keratoconus patients, Li et al. found that approximately 50 percent of clinically normal fellow eyes will progress to keratoconus within 16 years, with the greatest risk occurring in the first six years of onset.

The researchers recruited 778 keratoconus patients, in whom 116 (14.9 percent) had clinically unilateral keratoconus at baseline. Quantitative and qualitative videokeratography variables, contact lens wear and demographic variables were analyzed as potential predictive factors.

Results showed that clinically normal eyes might progress to keratoconus if they have high inferior-superior dioptric asymmetry values or asymmetric bowtie with skewed radial axes patterns.

They conclude that this information may prove valuable for predicting the future course of a keratoconus patient. Longitudinal studies using a longer period of time for follow-up are currently under way.

Topical Cyclosporin A Safe for Topical Steroid-Resistant Atopic Keratoconjunctivitis
March’s Ophthalmology

Results from a multicenter randomized trial by Akpek et al. indicate that topical cyclosporin A 0.05 percent is safe and of some benefit in the treatment of patients with atopic keratoconjunctivitis who are resistant to topical corticosteroids.

Twenty-two patients with atopic keratoconjunctivitis refractory to topical steroid treatment were randomly assigned to treatment with topical 0.05 percent cyclosporin A eye drops or a placebo for 28 days, six times daily for two weeks and then four times daily for two weeks.

The researchers observed five symptoms (itching, tearing, discomfort, mucous discharge and photophobia) and six signs (bulbar conjunctival hyperemia, upper tarsal conjunctival papillae, punctate keratitis, corneal neovascularization, cicatrizing conjunctivitis and blepharitis).

After a four-week period, the treatment group showed overall improvement in a composite summary of signs and symptoms compared with the placebo group.

Although the sample group was small, the authors conclude that cyclosporin A treatment is a viable alternative in patients with topical steroid-resistant atopic keratoconjunctivitis. Its use in the long-term or as a first-line agent requires further study.

Uveitis Is More Prevalent Than Previously Thought
March’s Ophthalmology

The first report from the Northern California Epidemiology of Uveitis Study—the largest of its kind to date in the United States—found the incidence and prevalence of uveitis higher than expected when compared with findings from previous studies.

The incidence of uveitis was approximately three times that of previous U.S. estimates and increased with older age. Women had a higher prevalence of uveitis than men, and the largest differences appeared in the older age group. The cross-sectional study at “midterm” consisted of 2,070 individuals within six Northern California medical center communities totaling 731,898 patients, who had a potential diagnosis of uveitis. Data from the study yielded an incidence of 52.4 per 100,000 person-years and prevalence of 115.3 per 100,000 persons. The incidence and prevalence of disease were lowest in children and highest in patients 65 years and older.

The authors conclude that the large size of this population-based research should add to the understanding of the epidemiology of uveitis in the U.S. population.


Endoscopically Assisted Balloon Dacryoplasty for Incomplete Nasolacrimal Duct Obstruction

March’s Ophthalmology

Couch and White found that endoscopically assisted balloon dacryoplasty is an excellent alternative for treatment of acquired incomplete nasolacrimal duct obstructions. Additionally, the use of nasal videoendoscopy enhances the benefit of this procedure and its potential for success.

The retrospective, noncomparative case series involved records of 142 nasolacrimal systems in 103 patients with incomplete nasolacrimal duct obstructions who underwent the procedure. A 3-by 15-millimeter balloon was used, with silicone lacrimal tubes placed in 131 systems.

Eighty systems (56 percent) experienced complete resolution of symptoms after surgery, 48 systems (34 percent) showed improvement but still experienced periodic epiphora and 14 systems (10 percent) showed no improvement at all.

The authors conclude that endoscopically assisted balloon dacryoplasty with nasal videoendoscopy should be considered as a beneficial treatment option for selected patients with incomplete nasolacrimal duct obstructions.

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Ophthalmology previews are written by Lori Baker Schena and edited by John Kerrison, MD.



Reviews

How Do Intraoperative Epithelial Defects Affect LASIK Outcomes?
American Journal of Ophthalmology
2004;111:244–249

Researchers at institutions in Latin America and the United States collaborated to evaluate whether intraoperative epithelial defects have an adverse effect on achieving desired refractive outcomes following LASIK for myopia.

In this retrospective case control study, 30 eyes that had intraoperative epithelial defects were compared with 60 randomly selected matched control eyes that had no intraoperative epithelial defects. Comparison variables included preoperative spherical equivalent, three- month postoperative BCVA, attempted correction, amount of undercorrection at three months postoperative and whether LASIK enhancement was performed at three months postoperative.

Eyes with intraoperative epithelial defects showed more undercorrection at three months (P = 0.005), were more likely to have lost lines of BCVA (P = 0.003) and underwent more enhancement procedures at three months (P = 0.004) in comparison with control eyes.

Intraoperative epithelial defects during LASIK seem to predispose eyes to increased wound healing leading to myopic regression, irregular wound healing with loss of BCVA and increased need for enhancement procedures.


Monitoring Changes in Liver Function Tests Can Help Predict Metastatic Uveal Melanoma
American Journal of Ophthalmology
2004;111:236–243

Kaiserman et al. evaluated trends in tests of liver function prior to detection of liver metastases from uveal melanoma.

This retrospective, comparative, observational case control study took place at the Israel uveal melanoma center at the Hadassah University Hospital. The researchers evaluated the records of 307 uveal melanoma patients and followed them between 1988 and 1998. The study included 30 metastatic patients who had regular follow-up by liver function tests and liver imaging. Eighty nonmetastatic patients were randomly chosen as controls. The medical records of the metastatic and control groups were reviewed documenting liver function tests and liver imaging results. The mean level of each liver function test, its sensitivity, specificity and likelihood ratio at various time periods prior to the detection of metastases by liver imaging were evaluated.

At the time of diagnosis of liver metastases by imaging, 50 percent of patients had at least one abnormal liver function test (compared with only 5 percent of the control group). No change was noted in the mean serum levels of bilirubin. However, mean lactate dehydrogenase, alkaline phosphatase, gamma-glutamyl transpeptidase, aspartate-aminotransferase and alanine-aminotransferase levels seemed to rise, even within normal limits, during the six months prior to the detection of metastases. Based on likelihood ratios, alkaline phosphatase and lactate dehydrogenase were the most predictive tests. Lactate dehydrogenase and aspartate-aminotransferase were already predictive at 80 percent of the upper normal limit, while alkaline phosphatase and gamma-glutamyl transpeptidase were most predictive at the upper normal limit.

The authors conclude that monitoring the changes in selected liver function tests, even within normal limits, can help predict metastatic uveal melanoma.

The Confocal Scanning Laser Ophthalmoscopy Study
American Journal of Ophthalmology
2004;111:219–227

Investigators in the Ocular Hypertension Treatment Study developed the Confocal Scanning Laser Ophthalmoscopy study as an ancillary study to examine the associations between optic disc topography and baseline demographic, clinical and ocular factors at study entry.

In this randomized clinical trial from seven of the 22 OHTS Clinical Centers, participants completed imaging annually using a CSLO, the Heidelberg Retina Tomograph. Associations between HRT topographic optic disc measurements and IOP, baseline photographic estimates of horizontal and vertical cup- to-disc diameter ratios by the OHTS Optic Disc Reading Center, baseline visual field indices and demographic and clinical factors were assessed using linear mixed effects models.

Good quality images were available from 439 participants. No associations between HRT topographic optic disc measurements and diabetes, systemic hypertension, cardiovascular disease, IOP or visual function were found. HRT topographic optic disc parameters were associated with baseline stereophotographic estimates of horizontal and vertical cup-to-disc diameter ratios. The strongest associations were found between stereophotographic assessment of horizontal and vertical cup-to-disc diameter ratios, and HRT cup-to-disc area ratio, rim-to-disc area ratio, mean cup depth and cup area. After adjusting for optic disc area, all HRT topographic optic disc parameters remained associated with stereophotographic assessment of horizontal and vertical cup-to-disc diameter ratios.



Cataract Progression Following Vitrectomy for Macular Holes and Epiretinal Membranes

American Journal of Ophthalmology
2004;111:250–264

Thompson evaluated the rate of increase in nuclear sclerosis and posterior subcapsular cataracts in eyes as a function of patient age and use of intravitreal gas at the time of vitrectomy.

In this observational case series, 301 consecutive eyes were graded for nuclear sclerotic cataracts and posterior subcapsular cataracts before and after vitrectomy for either macular hole or epiretinal membrane. Linear regression analysis was performed to measure and compare the rate of change in cataract score over time based on patient age and use of intraocular gas.

Nuclear sclerotic cataracts showed minimal increase in patients younger than 50 years old following vitrectomy (0.13 grades/year). Nuclear sclerotic cataracts increased at a rate of 0.7 to 0.9 grades per year in patients within the age ranges 50 to 60, 60 to 70, 70 to 80 and older than 80 years, even though the baseline nuclear sclerosis scores were progressively greater for each decade. The increase in nuclear sclerotic cataracts in patients younger than 50 was significantly less (P < 0.001) than in patients who were at least 50 years old. Eyes with intraocular gas use had a higher rate of nuclear sclerosis progression (0.8 grades/ year) compared with eyes without intraocular gas bubbles (0.5 grades/year; P < 0.001). Posterior subcapsular cataract scores showed minimal or no increases in all groups.

The author concludes that patients older than 50 have a similar rate of increase in nuclear sclerotic cataracts independent of age. The rate is approximately sixfold greater than in patients who were younger than 50. Intravitreal gas bubbles are associated with a nuclear sclerosis increase of approximately 60 percent compared with eyes without use of a gas bubble.


Informed Consent and Decision Making in Cataract Surgery
Archives of Ophthalmology
2004;122:94–98

Kiss et al. investigated the decision-making process in patients on the day before cataract surgery. They used a questionnaire to evaluate the informed consent procedure, presurgical information and personal estimation of risks.

Of the 70 patients who answered the questionnaire, 40 percent arrived at the hospital without any information and 76 percent estimated that there were no risks for their surgery. Only 28 percent wanted to make a decision together with their ophthalmologist; the majority wanted a physician-dominated decision. None of the patients was willing to rethink the decision to have cataract surgery and 77 percent stated that even sight-threatening complications would not influence their decision.

The researchers conclude that informed consent one day preoperatively does not seem to influence the decision for surgery because cognitive dissonance as an important part of the decision-making process makes changes very unlikely. The limited decisive potential of patients is very important for credibility and has to be considered in trials.

A Randomized, Prospective Trial Compares LASEK With PRK
Archives of Ophthalmology
2004;122:11–16

Pirouzian et al. compared LASEK and PRK in different eyes of the same 30 subjects in a randomized double-masked design.

All patients had LASEK performed in one eye and PRK performed in the other eye in the same sitting. The primary outcome measures were postoperative pain levels and the rate of corneal epithelial defect recovery (1 to 30 days postoperatively).

There were no significant differences in subjective pain levels between the LASEK and the PRK eyes. There was a statistically significant smaller median epithelial defect in the LASEK group compared with the PRK group on postoperative Day 1. However, by Day 3, the PRK group showed significantly smaller epithelial defects compared with the LASEK group. In summary, LASEK and PRK have similar levels of visual acuity recordings and pain thresholds postoperatively. However, the epithelial healing pattern for LASEK and PRK appears to be different.


Central Corneal Thickness and Advanced Glaucoma Damage
Archives of Ophthalmology
2004;122:17–21

Herndon et al. retrospectively reviewed the initial visit of each consecutive primary open-angle glaucoma patient who presented to one glaucoma specialist from 1997 to 2002.

The researchers analyzed a number of measures, including each patient’s age, sex, race, family history of glaucoma, IOP, central corneal thickness, visual field data and vertical and horizontal cup-to-disc ratios. In 190 patients, 350 eyes met the study’s criteria.

Lower central corneal thickness was significantly associated with worsened Advanced Glaucoma Intervention Study scores, worsened mean deviation of visual field, increased vertical and horizontal cup-to-disc ratios and an increased number of glaucoma medications. Central corneal thickness was significantly lower in blacks (mean 537 microns) than in whites (mean 556 µ).

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American Journal of Ophthalmology reviews are edited by Thomas J. Liesegang, MD. Archives reviews are edited by the researchers.

Round-Up of Other Journals

Dacryocystorhinostomy May Be Safely Completed Through a Retrocaruncular Approach
Graefe’s Archive for Clinical and Experimental Ophthalmology
2003;241:725–729

Adenis and Robert have found that a retrocaruncular approach for dacryocystorhinostomy is safe and effective, especially in regard to its cosmetic advantages. The key to its success is its ability to provide excellent and safe exposure of the posterior aspect of the lacrimal sac—avoiding the scarring associated with the skin approach.

This retrospective, noncomparative case series involved 11 procedures on 10 patients who underwent dacryocystorhinostomy using the retrocaruncular technique for nasolacrimal duct obstruction. After a follow-up period of 2.81 months, 82 percent of the cases achieved lacrimal patency.

The authors, who also describe the procedure in their report, explain that the main indication for the retrocaruncular technique is for cosmetic purposes, as the conjunctival incision—similar to the endoscopic approach—avoids the risk of epicanthus or a visible cutaneous scar. Additionally, this approach can be performed for patients with nasolacrimal obstruction even if the sac is dilated. However, the technique they describe does not allow for the combined treatment of a common canaliculus obstruction.

They conclude that the retrocaruncular approach offers several advantages, including an improved cosmetic effect.

Prognostic Factors in Pediatric Pilocytic Astrocytomas
Neurosurgery
2003;53:544–555

A study by Fernandez et al. shows that partial resection, optochiasmatic location, invasion of surrounding structures and the pilomyxoid variant are negative prognostic factors in pediatric pilocytic astrocytomas.

These brain tumors, which usually have a benign clinical course with 10-year survival ranging from 80 percent to 100 percent, are usually characterized by an excellent prognosis, but there are some instances where a patient experiences a bad outcome.

The researchers reviewed clinical, neuroradiological and histopathological features of 80 pilocytic astrocytomas in young patients. The mean overall follow-up period was 58 months, with the five-year progression-free survival rate at 75 percent, and the five-year survival rates at 100 percent after total removal and 92 percent after partial removal.

Reviewing the prognostic factors, specifically tumor location, optochiasmatic pilocytic astrocytomas carried the worst prognosis because complete surgical removal was never achieved and regrowth of tumoral residue was observed in 11 of 18 cases.

The authors conclude that some subgroups of pilocytic astrocytomas, for example those in an optochiasmatic location, may represent more aggressive variants and appropriate follow-up treatment should be considered.

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Round-Up is written by Lori Baker Schena and edited by Jose S. Pulido, MD, MS, MBA.

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