27 Gauge Vitrectomy; Current Indications and Management

Modern small incision vitrectomy, also known as microincision vitreous surgery, reflects the development of advances in surgical instruments and techniques. Methods for developing less invasive and smaller incision techniques with similar or better effectiveness for surgeons are developing rapidly. The 27-gauge vitrectomy method developed for vitreoretinal surgery has been introduced into our lives since 2010 and its use is becoming common increasingly. This article will discuss the current indication and use of 27-gauge vitrectomy.

Intraocular Temperature at Different Sites in Eye Measured at the Beginning of Vitreous Surgery

The temperature of the vitreous has been reported to vary during cataract and vitreous surgery. We measured intraocular temperature at four intraocular sites; the anterior chamber (AC), just behind the crystalline lens, mid-vitreous, and just anterior to the optic disc (OD) at the beginning of vitrectomy with a thermoprobe in 48 eyes. The temperatures were compared in three groups; eyes that underwent vitrectomy for the first time (Group V, n = 30), eyes that had previous vitrectomy and the vitreous cavity had been filled with balanced salt solution (BSS; Group A, n = 12), and eyes that had previous vitrectomy and the vitreous cavity was filled with silicone oil (Group S, n = 6). There was a gradient in the temperature in all groups, i.e., it was lowest in the AC, and it increased at points closer to the retina. The intraocular temperature was significantly correlated with the type of fluid in the vitreous cavity. The mean intraocular temperatures were not significantly different in Groups V and A, but they were significantly higher in Group S. Clinicians should be aware of the differences in the temperature at the different intraocular sites because the temperatures may affect the physiology of the retina and the recovery process.

A Case of Presumed Dyskeratosis Congenita Causing Severe Retinal Vascular Occlusion

Dyskeratosis congenita (DKC) is a rare, multisystem, bone marrow failure disease characterized by abnormalities such as in the skin, mucosa, nervous system, and lungs. Here we report a rare case of presumed DKC causing total retinal detachment in the right eye and severe peripheral retinal vascular occlusion in the left eye. A 3-year-old boy was presented with vitreous hemorrhage and total retinal detachment in the right eye and was scheduled to undergo vitreous surgery in the right eye and detailed ophthalmologic examination of the left eye under general anesthesia. Since a systemic examination revealed anemia and marked thrombocytopenia, he underwent a detailed pediatric examination. Although genetic testing revealed no significant pathologic mutations, the presence of shortened telomere length and other clinical findings suggested the possibility of DKC. His right eye had severe proliferative vitreoretinopathy, and retinal reattachment was not achieved with vitreous surgery, thus resulting in phthisis bulbi. The left eye showed a wide retinal avascular area in the temporal retina, retinal neovascularization, and hard exudates on fluorescein fundus angiography and was treated with laser photocoagulation using a binocular indirect ophthalmoscopic photocoagulator. Following laser surgery, the new blood vessels regressed, and the visual acuity was maintained at 1.0. The findings in this rare case indicate that DKC can cause severe retinal vascular occlusion, thus leading to vitreous hemorrhage and retinal detachment. Therefore, early detection with fundus examination and early treatment with photocoagulation are important.

A Case of Cyclodialysis after Microhook Trabeculotomy Treated with Vitreous Surgery

We report a case of cyclodialysis with decreased visual acuity after microhook trabeculotomy (mTLO) successfully treated by vitreous surgery. A 41-year-old man had been medically treated for primary open-angle glaucoma in both eyes. He was scheduled to undergo mTLO due to progression of visual field impairment and unstable intraocular pressure in his right eye. His preoperative best-corrected visual acuity (BCVA) was 0.4 OD, and the intraocular pressure was unstable, ranging from 12 to 27 mm Hg. On the day after the operation, a shallow anterior chamber developed, and a low intraocular pressure occurred. His visual acuity continued to decrease, and cyclodialysis was confirmed by ultrasonic biomicroscopy. No improvement was obtained with medical treatment, and his BCVA dropped to 0.08 OD, while his intraocular pressure remained at 2–3 mm Hg. Three months later, a second surgery was performed by combining cataract surgery with intraocular lens implantation, vitrectomy, cryopexy for the pars plana of the ciliary body, and 20% SF6 gas tamponade. Two weeks after the reoperation, the intraocular pressure had been normalized to 12 mm Hg, and the BCVA had returned to 0.3. We successfully treated cyclodialysis as a complication after mTLO by vitreous surgery that led to the recovery of the visual acuity and intraocular pressure.

Factors correlated with visual outcomes at two and four years after vitreous surgery for proliferative diabetic retinopathy

Proliferative diabetic retinopathy (PDR) is the most severe case of diabetic retinopathy that can cause visual impairment. This study aimed to reveal the factors correlated with better postoperative visual acuity after a long follow-up in patients who underwent vitrectomy for PDR. We retrospectively analyzed the data set including systemic findings, ocular findings, and surgical factors from registered patients who could be completely followed up for 2 or 4 years after vitrectomy. We ultimately enrolled 128 eyes from 100 patients who underwent vitrectomy for PDR between January 2008 and September 2012 and were followed up for >2 years. Among them, 91 eyes from 70 patients could be followed up for 4 years. Factors related to the postoperative visual acuity of ≥20/40 and ≥20/30 after 2 and 4 years were investigated by logistic regression analysis. Better postoperative visual acuity correlated with the following factors: no rubeosis iridis ([≥20/40 at 2 years; odds ratio {OR}, 0.068; 95% confidence interval {CI}, 0.012–0.39; P = 0.003], [≥20/30 at 2 years; OR, 0.07; 95% CI, 0.01–0.40; P = 0.03], [≥20/30 at 4 years; OR, 0.078; 95% CI, 0.006–0.96; P = 0.04]), no fibrovascular membrane [(≥20/40 at 2 years; OR, 0.22; 95% CI, 0.061–0.81; P = 0.02), (≥20/40 at 4 years; OR, 0.26; 95% CI, 0.07–0.94; P = 0.04), (≥20/30 at 4 years; OR, 0.14; 95% CI, 0.04–0.52; P = 0.004)], existing vitreous hemorrhage (≥20/30 at 2 years; OR, 9.55; 95% CI, 1.03–95.27; P = 0.04), and no reoperation ([≥20/40 at 4 years; OR, 0.15; 95% CI, 0.03–0.78; P = 0.02], [≥20/30 at 4 years; OR, 0.06; 95% CI, 0.07–0.54; P = 0.01]). Treatment provision before disease severity and treatment without complications were associated with good postoperative visual acuity.

Photoelectric dye-based retinal prosthesis (OUReP) as a novel type of artificial retina

We have developed the world's first novel type of artificial retina, OUReP (Okayama University Retinal Prosthesis), in which a photoelectric dye that converts light energy into electric potential is covalently bonded to the surface of a polyethylene thin film as an insulator. The receptor that absorbs light and the output device that generates displacement current to stimulate nearby neurons are integrated in a sheet of thin film. It has become possible to measure the surface potential of the artificial retina OUReP using a Kelvin probe that measures the surface potential of semiconductors. When light is turned on and off to the artificial retina OUReP, the surface potential changes rapidly. As the light intensity is increased, the potential change on the surface of the artificial retina becomes larger. As for safety, the artificial retina OUReP was not toxic in all tests for biological evaluation of medical devices. As for efficacy, the artificial retina OUReP was implanted under the retina by vitreous surgery in monkey eyes which had chemically-induced macular degeneration with photoreceptor cell loss. Over the next 6 months, retinal detachment did not occur during the course, and the artificial retina was in contact with the retinal tissue. The amplitude of the visual evoked potential attenuated by macular degeneration recovered 1 month after implantation of the artificial retina, and the recovery of amplitude was maintained until 6 months after the implantation. By using multielectrode array-mounted dish recording system, it has been proved that action potential spikes are induced when the artificial retina is placed on degenerative retinal tissue of retinal dystrophic rats or mice and exposed to light, which is used as an index of the effectiveness of the artificial retina. We have established manufacturing and quality control of the device in a clean room facility, proved the safety and efficacy, and are preparing for first-in-human investigator-initiated clinical trials.

Need for vitreous surgeries in proliferative diabetic retinopathy in 10 years follow-up: India Retinal Disease Study (IRDS) group Report no.2

Introduction: To report the 10 - year rate of vitrectomies and the associated factors in people with proliferative diabetic retinopathy (PDR) from a multicentric cohort of people with diabetes mellitus. Methods: Ten centres in India with established vitreoretinal services for over 10 years were invited to provide long-term data on PDR. People with Type 1 or 2 diabetes with a clinical diagnosis of active PDR in one or both eyes were included. Baseline data collected included age, sex, duration of diabetes, source of referral and best-corrected visual acuity and diabetic retinopathy status in both eyes. Available follow-up data included the numbers of panretinal photocoagulation (PRP) sessions, cataract surgery, treatment of diabetic macular edema, use of anti- vascular endothelial growth factor therapy, vitrectomy with or without retinal surgeries over 10 years. Results: Over 10 years, 89 % needed supplemental PRP after initial complete PRP. One – third required retinal surgery, 16 % needed intravitreal injection. Men (74.5%) had significant higher risk for vitreous surgery. Of the group with low risk PDR, 56.8% did not require vitreoretinal surgery, p <0.001. Of the patients who underwent cataract surgery and had intravitreal anti-VEGF injections, 78.5% and 28.2% needed subsequent vitreous surgery (VR), p=0.006 and <0.0001 respectively. Independent predictors of need for vitreo-retinal surgery included those who underwent cataract surgery and those with poor baseline visual acuity (logMAR). Eyes at lower risk for VR surgery included the eyes previously treated with PRP and low-risk PDR at baseline. Conclusion: Despite initial ‘complete’ PRP, one third of our study cohort needed vitrectomies over 10 years, highlighting that these patients require regular follow-up for a long period of time.

Measurement of Force Required for Anterior Displacement of Intraocular Lenses and Its Defining Parameters

Intraocular stability during or after cataract and glaucoma filtration surgeries and vitreous surgery with a gas/silicone oil tamponade might differ among intraocular lenses (IOLs). We used six different one-piece IOL models and measured the force that displaced the IOLs from the vitreous cavity to anterior chamber as a measure of stability against the pressure gradient between the anterior and posterior IOL surfaces. We measured IOL hardness, haptics junction area, and posterior IOL bulge to identify what determines the IOL displacement force. The KOWA YP2.2 IOL (1.231 mN) required significantly greater force than the HOYA XY1 (0.416 mN, p = 0.0004), HOYA 255 (0.409 mN, p = 0.0003), Alcon SN60WF (0.507 mN, p = 0.0010), and Nidek NS60YG (0.778 mN, p = 0.0186) IOLs; J&J ZCB00V IOL (1.029 mN) required greater force than the HOYA XY1 (p = 0.0032) and HOYA 255 (p = 0.0029) IOLs; the Nidek NS60YG IOL required greater force than the HOYA 255 (p = 0.0468) IOL. The haptics junction area was correlated positively with the IOL displacement force (r = 0.8536, p = 0.0306); the correlations of the other parameters were non-significant. After adjusting for any confounding effects, the haptics junction area was correlated significantly with the IOL displacement force (p = 0.0394); the IOL hardness (p = 0.0573) and posterior IOL bulge (p = 0.0938) were not. The forces that displace IOLs anteriorly differed among one-piece soft-acrylic IOLs, and the optics/haptics junction area was the major force determinant.