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In this month's Clinical Round Up, Sharon Freedman, MD, discusses results of the Infant Aphasia Treatment Study, and how it found there is no glaucoma protection from primary IOL placement in children. Additionally, Barbara Parolini, MD, discusses the new hope for better myopic traction maculopathy outcomes.
By Cheryl Guttman Krader
Durham, NC-Glaucoma-related adverse events are common after cataract removal in infancy-despite modern surgical techniques-according to results from follow-up to age 5 in the prospective, randomized Infant Aphakia Treatment Study (IATS).
In addition, they are consistent with previous studies in showing that young age and small corneal diameter at time of surgery are risk factors for these events, said Sharon F. Freedman, MD.
Primary IOL placement was not found to protect children having cataract surgery in infancy from developing glaucoma or becoming glaucoma suspects to age 5 years.
However, previous studies indicate that 5 years is the median age of onset of glaucoma after cataract surgery during infancy, and so the investigators are looking to longer follow-up when children reach 10 years of age for a more definitive answer about the potential impact of primary IOL placement.
“The issue of whether a primary IOL protects against development of glaucoma after cataract removal in infancy is controversial,” said Dr. Freedman, IATS investigator, chief of pediatric ophthalmology, Duke Eye Center, and professor of ophthalmology and pediatrics, Duke University School of Medicine, Durham, NC. “Two retrospective studies that did not use predefined definitions of glaucoma or glaucoma suspect and one recent meta-analysis suggested that it does. However, there are other retrospective studies and one prospective study that found a primary IOL was not protective after controlling for follow-up time and selection factors.
“A prospective randomized study was needed, and the IATS addresses that need,” she continued.
The IATS is a multicenter trial funded by the National Eye Institute that randomly assigned 114 infants ages 1 to 6 months undergoing unilateral cataract surgery to have in-the-bag primary IOL implantation with spectacle over-correction or to be left aphakic and wear a contact lens (CL). The primary outcome measure was visual acuity at age 5, but glaucoma was investigated as a secondary outcome.
The surgical procedure was standardized for all children and included cataract removal and posterior capsulotomy with anterior vitrectomy. Children with a small cornea (<9 mm), IOP >25 mm Hg at surgery, or persistent fetal vasculature causing visible stretching of ciliary processes were excluded from enrollment.
Glaucoma-related adverse events encompassed the outcomes of glaucoma and glaucoma suspect, and there were standard definitions for those diagnoses. Glaucoma was defined as IOP >21 mm Hg with one or more anatomic changes related to elevated IOP (corneal enlargement, asymmetrical progressive myopic shift with enlargement of corneal diameter and/or axial length, increased optic nerve cupping) or the need for a surgical procedure to control IOP.
Children were identified as glaucoma suspects if they had two consecutive IOP measurements >21 mm Hg on separate visits after topical corticosteroids were discontinued or needed medications to control IOP and did not have any of the anatomic changes included in the glaucoma definition.
At the age 5 follow-up (mean follow-up after surgery 4.8 years), 113 of 114 children remained in the study. The incidence of glaucoma-related adverse events in the operated eye had increased from 12% at follow-up conducted when children reached age 1 year to 32% (18% glaucoma, 14% glaucoma suspect). Nineteen (95%) of the 20 cases of glaucoma were open angle.
There were no glaucoma-related adverse events in fellow eyes. Visual acuity at age 5 was not significantly different comparing glaucoma eyes, glaucoma suspects, and those with neither condition.
Though the risk of a glaucoma-related adverse event increased with time, there was biphasic pattern noted in time to diagnosis, Dr Freedman noted. A number of cases occurred within the first 6 months after surgery, and then there was a relative plateau over the next 2.5 years.
Kaplan-Meier analyses showed there were no significant differences comparing the IOL and CL groups in the 5-year cumulative probability of having glaucoma (19% versus 16%) or being a glaucoma-related adverse even (28% versus 35%).
Multivariate analyses explored baseline factors of age, IOL versus CL group, persistent fetal vasculature, corneal diameter, and baseline IOP as possible risk factors for developing glaucoma or a glaucoma-related adverse event. For glaucoma, only younger age at surgery was a risk factor-children ages 28 to 48 days at surgery had a 3.2-fold increased risk compared with their older counterparts.
The only significant predictor for a glaucoma-related adverse event was smaller corneal diameter, with eyes having a corneal diameter ≤10 mm having a 2.9-fold greater risk than eyes with a larger corneal diameter.
Although treatment of glaucoma was not part of the IATS protocol, the information was tracked. Medication was used to control IOP in 19 (95%) eyes with glaucoma and 12 (75%) glaucoma suspects. Eight eyes (40% of eyes with glaucoma), including the eye with angle-closure glaucoma, underwent some type of surgery.
In addition to providing more data to determine if primary IOL placement affects the risk of a glaucoma-related adverse event after cataract surgery in infancy, longer follow-up in IATS may help to answer whether glaucoma behaves differently over time in eyes that had a primary IOL versus those left aphakic, or when the glaucoma develops early versus later after surgery.
“Glaucoma surgery seems to be required in eyes that developed glaucoma very early after cataract surgery, but it is effective,” Dr. Freedman said. “So far, the later onset cases have been mostly controlled with medications. However, we don’t know if this trend for later onset cases to be more indolent will continue.”
Sharon F. Freedman, MD
This article was adapted from Dr. Freedman’s presentation during the 2014 meeting of the American Academy of Ophthalmology. Dr. Freedman has no relevant financial interests to disclose.
By Lynda Charters
Brescia, Italy-Macular traction maculopathy can be challenging for surgeons. However, a macular buckle with a new design may be helpful for treating patients with posterior staphyloma without the need for a vitrectomy.
Barbara Parolini, MD, from the Instituto Clinica S.Anna, Brescia, Italy, explained that posterior staphyloma is ectasia of the posterior scleral wall. Because a similar ectasia does not develop in the retina, traction is exerted on the retina in the anteroposteriorly and tangentially. However, the former is the prevalent type and is most significant in the deepest side of the staphyloma.
When viewing optical coherence tomography (OCT) images, she advised surgeons to look at the deepest side of the staphyloma because that is the site where the lesions are present.
“It is the sclera that progressively detaches from the retina and not vice versa in highly myopic eyes,” said Dr. Parolini. “In fact, myopic traction maculopathy is a series of complications secondary to anteroposterior traction in eyes with posterior staphyloma.”
In these cases of posterior staphyloma, the natural history may be development of macular schisis and progression to a retinal detachment without a macular hole.
Regarding OCT, she also advised looking at long OCT scans of at least 12 mm.
“Compared with shorter scans, only the long scans show the entire profile,” she said.
An important concept, Dr. Parolini pointed out, is that the staphyloma in adults with high myopia progresses over time. She described a group of patients with high myopia who were followed by Japanese ophthalmologists for more than 20 years. As an example, a 42-year-old woman with a refractive error of -22 D had an axial length of 31.9 mm and by age 68 years, that axial length had increased to 33.3 mm.
Brian Curtin, MD, first classified Staphylomas in 1977, based on the location of the staphyloma.
“However, now we know that this is not a static, but rather a dynamic classification,” Dr. Parolini said. For example, a staphyloma classified as a type II staphyloma in a young patient can become a type IX over years with progression nasally and temporally to the optic nerve.
Because of this, there is a need to stop the progression behind the macula and the complications associated with progression, she added.
To address this issue, she has been working on a new design, specifically, an L-shaped macular buckle, to treat these patients.
In this procedure, a titanium stent is inserted into a 3-cm-long silicone sponge that is bent at a 90-degree angle to form long and short arms. The short arm is inserted in the superotemporal quadrant along the lateral rectus muscle, and then a fiberoptic is inserted into the short arm and is placed behind the macula.
The buckle is sutured anteriorly close to the insertion of the lateral rectus muscle.
“The buckle is very accessible and the surgery is easy to perform,” she said.
Dr. Parolini and her colleagues conducted a study of the effectiveness of this approach in 50 eyes with myopic traction maculopathy. Twenty eyes underwent a combined vitrectomy and placement of a macular buckle and 30 eyes underwent only a macular buckle procedure.
“The rate of retinal re-attachment was extremely high in both groups as was the rate of macular hole closure in eyes with a macular detachment,” she said. “The surgical time in the macular buckle group was half (average, 35 minutes) that in the combined surgery group.”
The best-corrected visual acuity may improve in these patients, she explained. In patients treated for a macular detachment with a macular hole, with the combined vitrectomy/macular buckle procedure and the macular buckle, only the patients either had improved vision or it remained unchanged from preoperatively.
“This was true for macular detachments without macular holes and for macular foveoschisis,” she said.
Complications of the macular buckle procedure included pain (mm2%), diplopia (4%), and extrusion through the conjunctive in 10% of the first 40 cases. Dr. Parolini pointed out that the extrusion was resolved when the buckle was shortened and use of the sponge was avoided in the lateral arm.
The investigators found that 2 weeks and 6 months after the macular buckle surgery only without vitrectomy the detachments resolved.
“Both procedures improved the vision in myopic traction maculopathy,” Dr. Parolini said. “The macular buckle only procedure is much faster and easier to perform compared with the combined procedure.
“I recommend that these patients undergo a buckle procedure alone first,” she continued. “Vitrectomy should never be performed without a buckle when there is posterior deep staphyloma. Combine vitrectomy and buckling in the presence of anteroposterior and tangential traction.”
Barbara Parolini, MD
This article was adapted from Dr. Parolini's presentation at the 2014 meeting of the American Academy of Ophthalmology. Dr. Parolini did not indicate any proprietary interest in the subject matter.