Glaukome durch erhöhten episkleralen Venendruck

[Ab interno trabeculotomy without/with cataract operation-An alternative treatment before or instead of trabeculectomy in patients with high intraocular pressure?]

BACKGROUND

Trabeculotomy with the Kahook knife is a new ab interno minimally invasive glaucoma surgery (MIGS) procedure. The MIGS are usually performed in early to intermediate glaucoma eyes. In this retrospective study we analyzed the intraocular pressure (IOP) and topical glaucoma eye drop therapy (Meds) reduction achieved by the Kahook trabeculotomy (TO) without (n = 19) or with (n = 18) combined cataract operation (Cat-TO) as initial treatment before or to avoid filtering surgery.

MATERIAL AND METHODS

A total of 37 eyes of 37 patients were examined when IOP was > 21 mm Hg in at least 2 examinations despite the maximum tolerable Meds applied. Cat-TO was performed in 18 phakic eyes (primary open-angle glaucoma, POAG = 11, pseudoexfoliation glaucoma, PEX = 5, ocular hypertension, OHT = 2). In 19 pseudophakic eyes (POAG = 12, PEX = 6, OHT = 1) an isolated TO was executed. Complete success (no Meds) and relative success (irrespective of Meds) for IOP ≤ 21 mm Hg, ≤ 18 mm Hg, ≤ 16 mm Hg were evaluated 2, 6 and 12 months postoperatively.

RESULTS

The IOP was significantly reduced from preoperatively to 2 months after Cat-TO as well as after TO (Cat-TO: 26.8 ± 5.9 mm Hg to 16.0 ± 2.9 mm Hg, p < 0.001; TO: IOD 28.2 ± 5.6 mm Hg to 16.3 ± 3.5 mm Hg, p < 0.001). Meds reduction after Cat-TO as well as after TO was not significant (Cat-TO: 2.1 ± 1.3 to 1.3 ± 1.3, p = 0.11; TO: Meds 2.7 ± 1.1 to 2.2 ± 1.3, p = 0.23); however, Meds reduction after 6 and 12 months was significantly greater in the Cat-TO group compared to the TO group (p = 0.02). The IOP and Meds did not change significantly from 2 to 6 months. After Cat-TO, qualified success after 12 months for IOP ≤ 18 mm Hg was 61% (11/18) and for IOP ≤ 16 mm Hg 28% (5/18). After TO, qualified success after 12 months for TO was 47% (9/19) for IOP ≤ 18 mm Hg and 26% (5/19) for IOP ≤ 16 mm Hg. The intervention was not sufficient for 7 patients after TO and 2 patients after Cat-TO (IOP two times > 21 mm Hg).

CONCLUSION

The first year results show that TO as well as Cat-TO are effective minimally invasive interventions to delay or even avoid a filtrating operation. In case of Meds intolerance and target IOP ≤ 16 mm Hg Cat-TO is not sufficient.

[Secondary open-angle glaucoma: uveitic secondary glaucoma, steroid-induced glaucoma, posttraumatic and postoperative glaucoma, tumor-related glaucoma and glaucoma due to elevated episcleral venous pressure]

Secondary open-angle glaucomas are a heterogeneous group of diseases in which a variety of pathophysiological mechanisms result in an elevation of intraocular pressure (IOP). In contrast to primary open-angle glaucoma in many cases besides IOP reduction a causal treatment is possible. This article is the second part of a review of the more frequently encountered forms of secondary open-angle glaucoma. Uveitic glaucoma, steroid-induced glaucoma, posttraumatic and postoperative glaucoma, glaucoma due to intraocular tumors and caused by elevated episcleral venous pressure are covered. The underlying pathophysiological mechanisms, characteristic clinical findings and treatment options are discussed.

Increased episcleral venous pressure in a mouse model of circumlimbal suture induced ocular hypertension

PURPOSE

To investigate changes in aqueous humor dynamics during intraocular pressure (IOP) elevation induced by circumlimbal suture in mice.

METHODS

Ocular hypertension (OHT) was induced by applying a circumlimbal suture behind the limbus in male adult C57BL6/J mice. In the OHT group, the suture was left in place for an average of 8 weeks (n = 10, OHT group). In the sham control group the suture was cut at 2 days (n = 9, sham group) and in the naïve control group (n = 5) no suture was implanted. IOP was measured at baseline across 3 days, 1 h post-suture implantation, and at the chronic endpoint. Anterior segments were assessed using optical coherence tomography (OCT). Episcleral venous pressure (EVP), total outflow facility (C), uveoscleral outflow (Fu) and aqueous humor flow rate (Fin) were determined using a constant-flow infusion model.

RESULTS

All aqueous dynamic and chronic IOP outcome measures showed no difference between sham and naïve controls (p > 0.05) and thus these groups were combined into a single control group. IOP was elevated in OHT group compared with controls (p < 0.01). Chronic suture implantation did not change pupil size, anterior chamber depth or iridocorneal angles (p > 0.05). EVP was significantly higher in OHT eyes compared to control eyes (p < 0.01). There was no statistical difference in C, Fu and Fin between groups (p > 0.05). A significant linear correlation was found between IOP and EVP (R² = 0.35, p = 0.001).

CONCLUSIONS

Circumlimbal suture implantation in mouse eyes results in chronic IOP elevation without angle closure. Chronic IOP elevation is likely to reflect higher EVP.

Congenital isolated idiopathic episcleral arteriovenous malformation

Purpose

To report the occurrence of an episcleral AVM and to discuss the gravity as well as management of dilated tortuous episcleral vasculature.

Observation

A 16-year-old Asian male presented with redness in the left eye since birth and a history of gradual painless progressive increase in size since the past two years, causing a cosmetic concern for the patient. There was no history of any diminution of vision, diplopia, headache, trauma or any similar lesions anywhere in the body.On examination, unaided visual acuity (UCVA) was 6/6 Snellen in both eyes. Hirschberg's reflex was central and extraocular movements were full and free in both the eyes.On slit-lamp examination, dilated tortuous episcleral vessels were found in the temporal aspect of the palpebral aperture, shaped like a single continuous vascular frond, vertically measuring 10-11mm in extent and horizontally commencing 6mm from the temporal limbus but the posterior limit could not be discernible. The episcleral plane was freely mobile from the overlying conjunctiva and underlying sclera. The dilated episcleral vasculature remained unchanged on Valsalava maneuver and on bending forward.Intraocular pressure was 14 mmHg by Goldmann's appalanation tonometer in both eyes. Iris was normal in configuration and gonioscopy revealed open angles without any evidence of any neovascularisation in both eyes. Fundus examination was unremarkable.USG B-scan was grossly normal. MR Angiography of head and orbit with using thin high-resolution cuts (1mm using 3T machine) was done and was later followed up with a Contrast Enhanced MRI. Both imaging studies revealed an isolated episcleral AVM with a possible feeder vessel from the anterior ciliary artery to the lateral rectus and without any intraorbital or intracranial lesion.A diagnosis of isolated episcleral AVM was made. The episcleral plane was dissected and dilated tortuous vessels were excised. After cautery, conjunctival autograft was obtained from the fellow-eye was used to cover the defect. Histopathological examination revealed both thick and thin walled vessels of varying calibre corresponding to arteries and veins confirming the diagnosis of isolated episcleral AVM. Ref. Fig. 2. No recurrence has been observed over a follow-up period of 1 year.

Conclusion

AND IMPORTANCE: Isolated idiopathic episcleral AVM should be a diagnosis of exclusion. A thorough systemic and ophthalmological evaluation including a glaucoma workup is necessary for both diagnosis and management. UBM and MRI/MRA may be required in select cases to rule out any associations or complications. Management includes observation, embolization and excision.