Intrastromal corneal ring implantation (360 degrees ring) for myopia: a 5-year follow-up.

PURPOSE: Stability of correction is a major factor for successful refractive surgery. Intrastromal corneal rings were placed for the correction of low to moderate myopia beginning 10 years ago. The purpose of this study was to evaluate findings in patients 5 years after ring placement and to compare these findings with 1-year results to assess the stability of effect. METHODS: Seventy-two patients (113 eyes) with myopia (range, -0.75 to -4.50 diopters [D]) were treated with the placement of intrastromal corneal rings (360 degrees ), in a multicenter clinical trial between 1993 and 1994 under U.S. Food and Drug Administration phase II and phase III clinical trials. Six insert sizes were evaluated: 0.21, 0.25, 0.30, 0.35, 0.40, and 0.45 mm. The long-term results that were evaluated were uncorrected visual acuity, best spectacle-corrected visual acuity, cycloplegic refraction spherical equivalent at 5 years and proximity of this value to the target refraction determined preoperatively, induced manifest refraction cylinder, and slitlamp findings. RESULTS: Data at the 5-year follow-up showed that uncorrected visual acuity was 20/40 or better in 83% of eyes and 20/20 or better in 64% of eyes, compared to 88% and 43%, respectively, at the first year of follow-up. Only 7% of eyes lost two or more lines of preoperative best spectacle-corrected visual acuity at 5 years, compared to 11% at the first year. No eyes at the 1- or 5-year follow-up had a best spectacle-corrected visual acuity worse than 20/40. Cycloplegic refraction spherical equivalent was within 1.00 D of target refraction in 68% of eyes at 5 years, compared to 71% at the 1-year follow-up. Induced manifest refraction cylinder greater than 1.00 D was reduced to 5% of eyes in the fifth year, compared to 12% of eyes at year 1. CONCLUSIONS: Intrastromal corneal rings are a safe, effective, and stable method of correcting mild to moderate myopia, and most patients continue to be satisfied with the results after 5 years. There was no clinically significant change in refractive effect and the central corneas remained clear at the 5-year follow-up in all eyes studied. Further data are currently being collected for 10-year follow-up periods. It is hypothesized that the use of intrastromal corneal rings as a refractive option for mild to moderate myopia will be supported by these additional longitudinal data.

Superior vena cava syndrome (SVC syndrome): a rare cause of conjunctival suffusion.

Obstruction of blood flow in the superior vena cava results in the signs and symptoms of superior vena cava (SVC) syndrome. Venous collaterals form, to establish alternative pathways for return of venous blood to the right atrium. The rapidity of onset of symptoms and signs from SVC obstruction is directly related to the rate at which obstruction occurs and how effective the formed collaterals are. Lung cancer and lymphoma account for more than 90% of cases of SVC syndrome. Recognition of signs and symptoms allows us to make an early diagnosis. Facial swelling, distended veins over the neck, upper extremity swelling, and dyspnea are common findings. Proptosis, periorbital swelling (including eyelid), conjunctival suffusion and elevated intraocular pressure are documented ophthalmic findings in SVC syndrome. We present a rare case of conjunctival suffusion in a 72-year-old male diagnosed with superior vena cava syndrome secondary to lung cancer.