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Retina Roundup

Timely and Important Retina News of Interest to All Ophthalmologists

Compiled by Andrew E. Mathis, PhD, Medical Editor

► Complications of vitrectomy for retained lens fragments. Retained lens fragments can be a serious complication of phacoemulsification, but vitrectomy to remove dropped nuclei can result in retinal detachment.

As retinal breaks are a necessary prerequisite for retinal detachment, a team of retinal physicians in Amsterdam examined the medical records of 89 consecutive phaco cases for the incidence of retinal breaks. They reported their findings in the September 2012 issue of Retina.

Eighty-nine cases were enrolled in the retrospective case series. Retinal breaks were found in 29% of the examined cases, but post-vitrectomy retinal detachment occurred in only 2% of the cases. Other complications included two cases of postoperative macular pucker, two cases of glaucoma and one case each of intraoperative choroidal hemorrhage and postoperative macular edema.

The authors concluded that intraoperative detection and treatment of retinal breaks greatly reduced the rate of postoperative retinal detachment in phaco cases.

► SD-OCT in elderly subjects. Spectral-domain OCT has contributed greatly to the diagnosis and treatment of retinal disease. The October issue of the British Journal of Ophthalmology featured a study of SD-OCT in subjects 60 and older, providing implications for its use in clinical trial design.

The study authors, from Germany and the Netherlands, conducted a retrospective analysis of 632 eyes of 316 elderly subjects without macular pathology. Their mean central retinal thicknesses were 280.22 μm and 281.02 μm in the left and right eyes, respectively. Men had thicker retinas, and the variation between left and right eyes in individual subjects was as great as 23 μm.

The key conclusion of the study was that to detect changes in retinal thickness of ≥30 μm, sample sizes of at least 90 subjects are necessary to enroll per arm. Future studies might derive greater power from enrolling at least this number of participants.

► CNV following LASIK. When LASIK is performed in patients with high myopia, a rare but potentially vision-threatening complication is choroidal neovascularization. International Ophthalmology recently published online a small case series of with this complication, which might prove useful to surgeons treating such cases.

Three Singaporean patients (two women and one man), with a mean age of 34 years old, underwent LASIK for high myopia. The mean period between LASIK and the appearance of symptoms of CNV was 9.3 weeks.

All three patients were treated with combinations of Visudyne/PDT and Lucentis. Similarly, all three patients experienced recovery of their vision, improving from 0.44 logMAR to 0.17 logMAR in BCVA, and two of the patients had complete resolution of CNV.

The authors recommended that all patients undergoing LASIK be informed of the possibility, albeit slight, of CNV and that fundus photos of these patients be obtained to screen for predisposing factors to CNV.

► Melphalan in retinoblastoma. Vitreous seeding is a troublesome complication of treating retinoblastoma that can result in recurrence. Ocular oncologists recently evaluated the use of melphalan, a chemotherapy agent, as an intravitreal injection in 12 children with retinoblastoma. Their findings appear in the October issue of Archives of Ophthalmology.

The children ranged in ages from 6 months to 7 years. Ten of these 12 children achieved success in controlling vitreous seeds at immediate follow-up, although that number dropped to six at more than six months.

Higher doses resulted in greater vitreous seed control but more side effects, including cataract, vitreous and subretinal hemorrhage and phthisis. Ultimately, two eyes were enucleated due to complications, although there were no cases of metastasis or orbital tumor recurrence.

► Pain with PRP. Traditional panretinal photocoagulation for diabetic retinopathy can be painful, so treatments with fewer spot burns and shorter durations have been developed. Graefe’s Archive of Clinical and Experimental Ophthalmology published an article online in October comparing pain scores in patients undergoing single-spot, short-pulse laser vs. traditional PRP.

Thirty-three patients had one eye undergo traditional PRP and the other undergo laser treatment of 20 msec in duration with a single spot size of 200 μm. Although more power and more spot burns were required with the experimental treatment, the pain scores were significantly lower (7.5 ±1.14 vs. 1.75 ±0.87). Further, changes in central macular thickness over four months of follow-up were greater in the conventional PRP group.

Though a small study, its prospective and randomized nature provides real power for concluding that short-duration, single-spot PRP is just as effective and less painful than conventional PRP.

► Foveal histology. The November 2012 issue of the American Journal of Ophthalmology features a retrospective case series describing the histologic development of the human fovea from 22 weeks of gestation to 13 years old. Using donor tissue, the study authors examined retinal layers and structures in 33 eyes, finding significant histologic changes over the entire period of study.

The authors stated their data are necessary to understanding the profound changes that the human retina undergoes over its development, into early adulthood. They further stated that these data will enable better interpretation of OCT results in pediatric patients. OM