Preoperative optical coherence tomography can predict surgical, acuity outcomes

October 15, 2008

Optical coherence tomography performed preoperatively can predict the surgical success rates and the visual acuity outcomes in patients with myopic macular holes.

Key Points

Osaka, Japan-Patients with high myopia, macular holes, and no retinal detachment have better visual outcomes compared with patients with high myopia, a macular hole, and a localized retinal detachment with surrounding retinoschisis and compared with patients with high myopia with a macular hole and a retinal detachment within the area of posterior staphyloma and no retinoschisis. This assessement is according to Yasushi Ikuno, MD, associate professor, Department of Ophthalmology, Osaka University Medical School, Osaka, Japan.

Macular holes, according to Dr. Ikuno, are a major complication in high myopia; vitrectomy with peeling of the internal limiting membrane peeling and gas tamponade generally is the procedure of choice. The preoperative predictive factors include chorioretinal atrophy and foveal morphology including simple macular holes with a retinal detachment or with foveoschisis. Closure of the macular hole also is an important factor after the surgery.

"Closure of the macular hole is very important for improvement in visual acuity," he said. "There are two important problems to consider with myopic macular holes, the first of which is why the macular hole closure rates differ so greatly and range from 10% to 100%, because of the difficulty of observing the fundus due to atrophy. The second problem is that the foveal conditions vary considerably before surgery. A high success rate is expected if there is no retinal detachment, and a low success rate is associated with a retinal detachment or retinoschisis. Unfortunately, no comparative studies have been conducted, and it is still difficult to make an accurate prediction of the outcomes after surgery."

Dr. Ikuno and his colleagues addressed the question of the usefulness of performing optical coherence tomography (OCT) preoperatively to determine accurate surgical outcomes in myopic macular holes. The investigators retrospectively reviewed the records of patients who had undergone vitrectomy for highly myopic macular holes. They assessed the preoperative OCT morphology concerning the postoperative visual and anatomic outcomes in patients with myopic macular holes.

The surgical outcomes were determined by the best-corrected visual acuity, and the macular hole closure rate that was confirmed by OCT 6 months postoperatively. Thirty-nine eyes of 39 patients (eight men, 31 women; mean age 62 years; range, 40 to 79 years) with myopic macular holes were included; all patients' conditions had been diagnosed using OCT. All patients had undergone vitrectomy, internal limiting membrane peeling, and gas tamponade.

The patients were grouped based on the OCT findings. Eight patients had a macular hole and no retinal detachment or schisis (group 1); 23 eyes had a macular hole with a localized retinal detachment with surrounding retinoschisis (group 2), and eight eyes had a retinal detachment with posterior staphyloma and no retinoschisis (group 3). There was no significant difference among the groups in age, gender, or axial length.

The height of the posterior staphyloma was measured on OCT. The retinal pigment epithelial (RPE) layer was identified at the apex of the posterior staphyloma and the end. The vertical distance between these points was measured by a digital image processing application (IMAGEnet, Topcon). The sum of both distances was defined as the height of the posterior staphyloma height.

The height of the posterior staphyloma in 50% of the eyes could not be measured because there was no RPE image for group 3. The height of the posterior staphyloma in group 2, with a macular hole with a localized retinal detachment and surrounding retinoschisis was significantly (p <0.05) higher than in group 1 with a macular hole and no retinal detachment or schisis.

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