Guided Trocar Insertion in Highly Myopic Eyes

PURPOSE

To demonstrate through a diagnostic test used as a new preoperative assessment that trocar insertion for pars plana vitrectomy could be safely placed at a distance >4.0 mm in highly myopic eyes to facilitate the surgical maneuvers.

METHODS

Thirty eyes of 30 patients were tested with a biometer for the axial length measurement and with ultrasound biomicroscopy to measure the pars plana length. Pars plana lengths of highly myopic eyes were then compared with those of emmetropic eyes. The surgeon also measured the pars plana of highly myopic eyes intraoperatively and compared it with ultrasound measurements to assess ultrasound biomicroscopy reliability.

RESULTS

The mean axial length was 23.81 mm (SD ± 0.30) in the control group and 31.11 mm (SD ± 0.56) in the myopic group. The mean pars plana length was 4.96 mm (SD ± 0.19) in control eyes and 6.65 (SD ± 0.36) in myopic eyes. An extremely significant statistical difference ( P < 0.001) was obtained by comparing the length of pars plana between control eyes and myopic eyes. The results of pars plana measurements were 6.65 mm (SD ± 0.36, ultrasound biomicroscopy) and 6.66 mm (SD ± 0.34, intraoperative measurements) in myopic eyes. The statistical comparison of the measurements in these two groups did not give a statistically significant result ( P = 0.950).

CONCLUSION

Ultrasound biomicroscopy is a reliable technique to calculate the length of pars plana in highly myopic eyes, where this parameter is significantly greater than that of emmetropic eyes. Trocars insertion for pars plana vitrectomy may be performed, in eyes with axial length >30 mm, in relative safety at a distance to limbus higher than 4 mm.

ANTERIOR SEGMENT OPTICAL COHERENCE TOMOGRAPHY IN DETERMINATION OF ENTRY SITE FOR VITRECTOMY IN HIGHLY MYOPIC EYES

PURPOSE

To evaluate the efficacy of anterior segment optical coherent tomography (AS OCT) in estimating the length of the pars plana and optimizing the sclerotomy entry site in vitrectomy for highly myopic eyes, facilitating membrane peeling.

METHODS

Twenty-three eyes with myopic traction maculopathy were studied. The pars plana was examined using two methods: preoperative AS OCT and intraoperative measurement. The distance from the limbus to the ora serrata in two groups was measured to compare differences in length. The actual length of the entry site from the limbus and forceps used were noted in all eyes studied.

RESULTS

The mean axial length was 29.2 ± 2.3 mm for all 23 eyes. The average length between the limbus and ora serrata measured with AS OCT and intraoperative examination was 6,710 µ m (SD ± 459) and 6,671 µ m (SD ± 402), respectively, in the superotemporal region ( P > 0.05), and 6,340 µ m (SD ± 321) and 6,204 µ m (SD ± 402), respectively, in the superonasal region ( P >0.05). The mean length of the entry site from the limbus was 6.2 mm, and 28-mm forceps were used in 17 of 23 eyes (77%).

CONCLUSION

The length of the pars plana varies depending on the axial length of the eye. Preoperative AS OCT enables accurate measurement of the pars plana in eyes with high myopia. AS OCT examination can help determine the optimal site for sclerotomy, allowing easier access to the macular region for membrane peeling in highly myopic eyes.

Long-term outcomes of pars plana Ahmed valve implant and vitrectomy in eyes with refractory glaucoma

Background

Pars plana vitrectomy with implantation of an Ahmed glaucoma valve in the vitreous cavity has been reported with a success rate in the management of refractory and neovascular glaucoma. This study aimed to present the outcomes of pars plana Ahmed glaucoma valve (PPAV) surgical implantation in cases with refractory glaucoma.

Methods

In this single-center, retrospective, comparative study, 87 consecutive patients diagnosed with refractory glaucoma who underwent PPAV surgical implantation between October 2015 and October 2019 were evaluated. A successful postoperative outcome was defined as intraocular pressure (IOP) ≤ 21 mmHg upon examination and a reduction in the number of anti-glaucoma agents used at the latest follow-up.

Results

Finally, 81 eyes of 78 patients with refractory glaucoma were included; 54 (66.66%) of the eyes had neovascular glaucoma. The mean follow-up was 20.65 ± 12.17 months (range: 2-52 months). The mean preoperative IOP was 40.01 ± 1.19 mmHg and reduced significantly to 16.73 ± 0.82 mmHg at the latest follow-up (P < 0.001); a successful IOP outcome was achieved in 88.89% of eyes. The mean number of anti-glaucoma agents decreased significantly from 2.86 ± 0.09 preoperatively to 1.46 ± 0.11 at the latest follow-up (P < 0.001); while 61 (75.31%) of eyes had a reduction in the number of IOP lowering eye drops, and 14 (17.28%) had no need for IOP lowering eye drops.

Conclusions

PPAV surgery is a successful procedure for IOP reduction in patients with refractory glaucoma. Our study demonstrated either reduction or elimination of IOP lowering eye drops postoperatively. Large scale studies with a comparison group, a longer follow-up, and having various subtypes of glaucoma are required as future research to confirm these outcomes.

Localized Choroidal Melanoma Managed by Pars Plana Endoresection, Endodiathermy, and Endolaser

Choroidal melanoma, although rare, is the most common primary intraocular malignancy among adults, with an incidence ranging from 6 to 7.5 cases per million per year globally. This tumor originates from the uveal tract’s melanocytes in the eye. Melanomas usually arise from the sixth decade of age with increasing incidence with progressive age.

A 60-year-old male presented with a right-sided sudden painless decrease in vision due to a grade 4 vitreous hemorrhage. B-scan ultrasonography and CT scan of the orbits revealed a mushroom-shaped choroidal mass highly suggestive of choroidal melanoma, which was managed surgically with pars plana endoresection, endodiathermy, and endolaser.

Endoresection can be an effective method for the management of solitary non-metastasized choroidal tumors, especially those that have become symptomatic. Pre and post-surgical imaging are necessary, along with careful follow-up to detect any recurrence.

In Vitro Comparison of Various High-Speed Vitrectomy Machines Using Dual Blade Cutters

Objectives

The objective of this study is to compare various dual blade vitrectomy cutters for their efficiency in an in vitro setting.

Methods

In this in vitro experimental study, we compared various vitrectomy systems including EVA (Dutch Ophthalmic Research Center, Zuidland, The Netherlands), REVOLUTION (Optikon 2000, Inc., Rome, Italy), and OS4 (Oertli Instrumente AG, Berneck, Switzerland) in terms of efficiency in vitreous cutting and aspiration for various vitreous substitutes. These substitutes included water, chicken egg albumin, and goat vitreous. We only used 23-gauge dual blade cutters across all platforms to maintain uniformity. The cutting and aspiration efficiency was measured across various cut and vacuum settings of vitrectomy machines and measured as mass aspirated in a given time. Data analysis included comparing the amount of mass aspirated by these machines at preset cut and vacuum settings.

Results

Scatter plots showed a comparable mass of water aspirated by the EVA and REVOLUTION at 1000 to 5000 cuts per minute at a constant vacuum of 500 mm Hg whereas OS4 aspirated lesser mass at similar settings. Same trends were noted for goat vitreous for EVA and REVOLUTION but aspirated mass of albumin fluctuated widely across various platforms. At peak machine settings, REVOLUTION showed superiority across all three vitreous models due to its higher peak settings. The area under curve (AUC) analysis showed no significant differences among machines for water and goat vitreous at comparable settings but results were fluctuating for egg albumin.

Conclusion

Employing higher cut rates for dual blade cutters results in better efficiency of vitrectomy machines.

Case Report on Giant Pars Plana Cysts Mimicking Retinal Detachment

Purpose

To report a case of peripheral elevated lesions mimicking retinal detachment which were ultimately ascertained to be giant pars plana cysts through ophthalmoscopy with scleral depression.

Methods

This was a case report documented with ophthalmoscopy and Optos imaging.

Results

Patient initially referred for assessment of bilateral retinal detachment was found by careful ophthalmoscopy with scleral depression to have bilateral giant pars plana cysts with no frank retinal breaks.

Conclusion

Large pars plana cysts may mimic retinal detachment or other peripheral retinal pathology. The lesions in question were found to originate from the pars plana and overhang the retina. No frank retinal breaks or associated rhegmatogenous retinal detachments were noted in either eye. Ophthalmoscopy with a complete scleral depressed exam allowed for the differentiation.

Ultrabiomicroscopic Findings in Acute Uveitic, Convalescent and Chronic Recurrent Stage of Vogt-Koyanagi-Harada Syndrome

PURPOSE

To describe the ultrabiomicroscopy (UBM) characteristics in patients with uveitic, convalescent, and recurrent Vogt-Koyanagi-Harada (VKH) disease.

METHODS

In this prospective, non-interventional, and observational study, all UBM variables, namely pars plicata and pars plana thickness, ciliochoroidal detachment, angle chamber, anterior chamber depth, ID2, and presence of ciliary processes, were compared between acute uveitic, convalescent, and chronic-recurrent phases.

RESULTS

Ninety-one eyes were analyzed. Ciliochoroidal detachment (20%) and unclear ciliary processes (15%) are the most characteristic findings of the uveitic phase. At 1 and 3 months, ciliochoroidal detachment is no longer observed. In recurrent phase, pars plicata and pars plana thickness increases again and then decreases after the first month of treatment. Convalescent-phase does not show significant differences in UBM variables after a 6-month follow up.

CONCLUSIONS

UBM may have a role in evaluating response to treatment in uveitic and recurrent phases and in the early detection of recurrences.

Pars plana Ex-Press mini shunt for management of persistent glaucoma in vitrectomized eyes: A novel technique

PURPOSE

To evaluate the safety and efficacy of a novel approach to implant Ex-Press mini shunt via the pars plana under a scleral flap in pseudophakic or aphakic, vitrectomized patients with secondary refractory glaucoma.

METHODS

A prospective interventional case series of three patients with secondary glaucoma after pars plana vitrectomy. Intraocular pressure was not controlled by silicone oil removal, if the patient was siliconized, nor the maximum medical treatment. Ex-Press mini shunt via the pars plana was implanted. We evaluated the control of intraocular pressure and the development of intraoperative and postoperative complications.

RESULTS

During 1-year follow-up, control of intraocular pressure was achieved; 14, 15, and 15 mmHg at the 3 months, and 15, 15, and 16 mmHg at the 6 months in our three cases without antiglaucoma treatment and 16, 16, and 18 with single antiglaucoma medication at 1 year. Blebs were posterior and diffuse. No complications were encountered intraoperatively or postoperatively. Ultrasound biomicroscopy showed suprachoroidal posterior lake of fluid as an additional filtration route without any choroidal or retinal complication.

CONCLUSION

Implantation of Ex-Press mini shunt via the pars plana in aphakic or pseudophakic, vitrectomized eyes is a promising, safe, and effective technique in patients with secondary glaucoma.

Wide-field fundus imaging with trans-palpebral illumination

In conventional fundus imaging devices, transpupillary illumination is used for illuminating the inside of the eye. In this method, the illumination light is directed into the posterior segment of the eye through the cornea and passes the pupillary area. As a result of sharing the pupillary area for the illumination beam and observation path, pupil dilation is typically necessary for wide-angle fundus examination, and the field of view is inherently limited. An alternative approach is to deliver light from the sclera. It is possible to image a wider retinal area with transcleral-illumination. However, the requirement of physical contact between the illumination probe and the sclera is a drawback of this method. We report here trans-palpebral illumination as a new method to deliver the light through the upper eyelid (palpebra). For this study, we used a 1.5 mm diameter fiber with a warm white LED light source. To illuminate the inside of the eye, the fiber illuminator was placed at the location corresponding to the pars plana region. A custom designed optical system was attached to a digital camera for retinal imaging. The optical system contained a 90 diopter ophthalmic lens and a 25 diopter relay lens. The ophthalmic lens collected light coming from the posterior of the eye and formed an aerial image between the ophthalmic and relay lenses. The aerial image was captured by the camera through the relay lens. An adequate illumination level was obtained to capture wide angle fundus images within ocular safety limits, defined by the ISO 15004-2: 2007 standard. This novel trans-palpebral illumination approach enables wide-angle fundus photography without eyeball contact and pupil dilation.

A modified approach to actively remove high viscosity silicone oil through 23-gauge cannula

AIM

To report a simple approach to actively remove high viscosity silicone oil through a 23-gauge cannula via pars plana.

METHODS

Forty-eight eyes of 48 patients underwent silicone oil (5700 centistokes) removal (SOR) were enrolled. A section of blood transfusion set was prepared to connect a standard 23-gauge cannula and vitrectomy machine. Silicone oil was removed with suction of 500-mm Hg vacuum through the cannula. Main outcome measures were SOR duration, number of sutured sites, intraocular pressure (IOP), best-corrected visual acuity (BCVA), and complications.

RESULTS

Silicone oil was successfully removed in all cases. The mean SOR time was 5.70±0.85min. Nine eyes (18.75%) needed suture partial sclerotomies. No intraoperative complications were noted. Transient hypotony (≤8 mm Hg) was seen in 3 eyes (6.25%) on postoperative day 1, but all resolved within 1wk. Retinal reattachment was achieved in all cases and no other postoperative complications were noted during 3-month following-up. BCVA at the final visit improved or stabilized in all patients comparing to the preoperative level.

CONCLUSION

Active removal of high viscosity silicone oil through a 23-gauge instrument cannula jointed with blood transfusion set is a practical and reliable technique when considering two sides of efficacy and safety.

Full thickness macular hole: Early intervention is an important factor in visual prognosis

Full thickness macular hole is an eye disease, which can cause permanent visual impairment. Current advancement in vitreoretinal surgery has high success rates in repairing them, leading to a significant visual improvement, especially if patient presents early. In this article, three cases of idiopathic full thickness macular hole with different visual outcomes have been presented. All cases were referred by the primary care practitioners and had undergone macular hole surgery with the same vitreoretinal surgeon. The visual outcome was best in the patient who had the earliest presentation and referral. Early detection and referral of these patients is vital so that early surgical intervention can be carried out to improve their vision.

A case involving an Ahmed™ glaucoma valve transferred from the vitreous into the anterior chamber of the eye with a silicone oil tamponade for the treatment of neovascular glaucoma

PURPOSE

To report the short-term efficacy and safety of the transfer of an Ahmed(™) glaucoma valve (AGV™) tube from the vitreous into the anterior chamber, in a patient with neovascular glaucoma who had undergone pars plana AGV(™) implantation and ultimately needed a silicone oil tamponade.

CASE

A 41-year-old male with proliferative diabetic retinopathy in both eyes was referred to us for treatment in December 2009. Although the patient previously underwent several surgeries, he ultimately lost vision in his right eye. His left eye suffered from neovascular glaucoma after undergoing a pars plana vitrectomy for tractional retinal detachment. After several vitreous and glaucoma surgeries, the patient underwent implantation of a pars plana AGV™. Postoperatively, although his intraocular pressure was stabilized at approximately 10 mmHg, he had repeated vitreous hemorrhage and hyphema without improvement. He ultimately underwent PPV with a silicone oil tamponade and at the same time, the AGV™ tube was pulled out from the vitreous and inserted into the anterior chamber in order to avoid complications caused by the silicone oil.

RESULTS

At 19 months postoperative, the patient's intraocular pressure had stabilized at 10 mmHg with no recurrence of vitreous hemorrhage and hyphema. Eventually, he lost vision in his left eye because of cerebral hemorrhage.

CONCLUSION

The findings show that insertion of a pars plana AGV™ tube into the anterior chamber in a patient undergoing a silicone oil tamponade is both effective and safe in the short-term.