TREATMENT OF PERSISTENT MACULAR HOLES WITH HEAVY SILICONE OIL.

BACKGROUND/PURPOSE: To determine anatomical success and best-corrected visual acuity after secondary surgery with heavy silicone oil tamponade in patients with persistent full-thickness macular holes. METHODS: In this retrospective study, 63 eyes with persistent full-thickness macular holes after primary pars plana vitrectomy and internal limiting membrane peeling underwent secondary surgery with heavy silicone oil tamponade. Macular spectral domain optical coherence tomography and best-corrected visual acuity measurements were performed during the follow-up. RESULTS: Fifty of 63 eyes (79.4%) achieved anatomical success. In eyes achieving anatomical success, best-corrected visual acuity before primary vitreoretinal surgery was significantly better (0.77 [∼20/125 Snellen] ± 0.24 [1.3-0.3] logarithm of the minimum angle of resolution) compared with eyes not achieving anatomical success (0.88 [∼20/160 Snellen] ± 0.17 [1.1-0.6] logarithm of the minimum angle of resolution, P = 0.044). Minimum linear diameter of full-thickness macular holes was significantly smaller in eyes achieving anatomical success, both before primary (403.4 ± 128.7 [199.0-707.0] µ m vs. 568.1 ± 209.1 [307.0-953.0] µ m, P = 0.009) and secondary surgery (464.1 ± 215.0 [178.0-1,521.0] µ m vs. 663.3 ± 228.5 [451.0-1,301.0] µ m, P = 0.010). Patients remaining phakic during all three surgeries did not benefit from best-corrected visual acuity improvement, although anatomical success was achieved. CONCLUSION: Heavy silicone oil tamponade in secondary surgery for persistent full-thickness macular holes is a safe and efficient surgical method. Best-corrected visual acuity and minimum linear diameter before surgery may be indicators for anatomical success.

Dose-response-relationship between number of laser burns and IOP reduction in cyclophotocoagulation: an animal study.

PURPOSE: The relationship between number of laser burns of cyclophotocoagulation (CPC) and intraocular pressure (IOP) reduction is unknown. This animal model was established to reveal a possible dose-response-relationship between the number of applied laser burns and the IOP lowering effect. METHODS: 30 chinchilla bastard rabbits were divided into 5 groups and treated with either 1, 5, 10, 20, or 30 CPC burns, respectively. IOP was followed up for 1 week. IOP reduction of a single 30-burn treatment was compared with a fractionated treatment (three sessions; one week in between; 10 burns/session). RESULTS: IOP reduction increases nonlinearly with the number of CPC burns (max. -6.1 ± 1.4 mmHg). Fractionated treatment shows similar IOP reduction with less complications and more constant results compared to single session treatment. CONCLUSIONS: The study reveals a complex relationship between IOP reduction and the number of CPC burns. Fractionated CPC gives comparable IOP reduction at a higher degree of safety.

The effect of cataract surgery on blue-yellow and standard-pattern visual-evoked potentials.

PURPOSE: Blue-yellow visual-evoked potentials (BY-VEPs) may be used for diagnostics of functional ganglion cell damage in glaucoma and other ocular diseases. In this study we investigated the impact of lenticular opacities on BY- and standard pattern reversal VEPs by examining patients before and after cataract surgery. METHODS: Eighteen patients with moderate cataract were included in a prospective study. Transient on/off isoluminant blue-yellow 2° checks were used for short-wavelength stimulation (BY-VEP), transient large 1° (M1) and small 0.25° (M2) black-white checks for standard pattern reversal VEPs. VEPs were acquired before (24 ± 30 days) and after cataract surgery (14 ± 16 days). The contralateral eye was used as a control. RESULTS: Amplitude and latency of M1 and M2 peaks did not change significantly from before to after surgery. The amplitude of the BY-VEPs did not change significantly after cataract surgery (pre-surgery, -7.42 ± 3.43 µV, post-surgery, -7.93 ± 3.65 µV, p = 0.42), yet the latency of the main negative peak showed a significant decrease (pre-surgery, 143.9 ± 12.9 ms, post-surgery, 133.2 ± 7.7 ms, p = 0.0006). The BCVA improvement was significant from before to after cataract surgery (pre-surgery, 0.344 ± 0.125 LogMAR, post-surgery, 0.224 ± 0.179 LogMAR, p = 0.013) yet not correlated to the absolute decrease in latency of the BY-VEP after surgery (r = 0.309, p = 0.22). No significant changes were found in the contralateral eye. CONCLUSIONS: The BY-VEP is sensitive to lenticular opacities of the human lens, presumably due to the increased short-wavelength absorption in the aging eye. This fact should be considered when applying BY-VEPs for diagnostics.

Clinical observations and occurrence of complications following heavy silicone oil surgery.

PURPOSE: To demonstrate development and complications in heavy silicone oil (HSO) surgery in 100 eyes following primary vitreoretinal surgery. METHODS: 100 eyes were included in this retrospective study that underwent vitreoretinal surgery using HSO as endotamponade. Indication diagnoses were retinal detachments (n = 76), complicated macular holes (MH) (n = 20), and others (n = 4). HSO removal was performed after a mean period of 20.2 ± 19.0 weeks. In 18 eyes with poor functional prognosis the silicone oil remained permanently for stabilisation. Overall follow-up time was 35.9 ± 51.8 weeks. RESULTS: The mean IOP before HSO surgery was 13.3 ± 5.6 mmHg and raised to an average maximum of 23.3 ± 8.5 mmHg postoperatively and decreased to 13.7 ± 7.2 mmHg after removal. Secondary IOP raise due to emulsification of the silicone oil endotamponade was seen in 29 eyes after 7.8 ± 4.5 weeks. Other complications being observed with HSO installed were persistent corneal erosion (n = 3) and prolonged anterior chamber inflammation (n = 29). In 13 eyes recurrent retinal detachments occurred during followup. CONCLUSIONS: According to our analysis HSO surgery might deliver satisfying results in complicated cases of ophthalmological surgery. However, potential complications should always be taken into account when making the decision if to use and when to remove HSO in complicated retinal surgery.