Indian Journal of Ophthalmology

ORIGINAL ARTICLE
Year
: 2002  |  Volume : 50  |  Issue : 2  |  Page : 123--126

Indocyanine green enhanced maculorhexis in macular hole surgery


A Kumar, G Prakash, Rajender P Singh 
 Dr. R. P. Centre for Ophthalmic Sciences, AIIMS, Ansari Nagar, New Delhi

Correspondence Address:
A Kumar
Dr. R. P. Centre for Ophthalmic Sciences, AIIMS, Ansari Nagar, New Delhi

Abstract

Purpose: To demonstrate the usefulness of staining the internal limiting membrane (ILM) with a solution of indocyanine green (ICG) to facilitate the removal of ILM in eyes with idiopathic macular hole. Methods: Eighteen patients underwent vitrectomy with the removal of posterior cortical vitreous, induction of posterior vitreous detachment (PVD), ICG-enhanced removal of the macular ILM, and fluid-gas exchange, followed by facedown positioning. Results: Fifteen (83.33%) of the macular holes were closed at 3 months postoperatively. The visual outcome was relatively better in holes smaller than 400 microns in diameter, as compared to bigger macular holes (more than 400 microns in diameter). Of the 18 eyes, 9 (50%) recorded visual improvement of 2 or more lines over the preoperative level. Conclusion: Our results show the safety and usefulness of this technique in visualization of the ILM during macular hole surgery, thereby leading to successful removal of optimal amount of ILM, with minimum damage to the retina.



How to cite this article:
Kumar A, Prakash G, Singh RP. Indocyanine green enhanced maculorhexis in macular hole surgery.Indian J Ophthalmol 2002;50:123-126


How to cite this URL:
Kumar A, Prakash G, Singh RP. Indocyanine green enhanced maculorhexis in macular hole surgery. Indian J Ophthalmol [serial online] 2002 [cited 2024 Mar 28 ];50:123-126
Available from: https://journals.lww.com/ijo/pages/default.aspx/text.asp?2002/50/2/123/14809


Full Text

Idiopathic full thickness macular hole is an important cause of central visual loss. Macular hole formation begins with the degeneration of the inner retina at the Muller cell cone-vitreous cortex interface. The macular defect enlarges due to the contraction of the internal limiting membrane (ILM) because of Muller (Glial) cell migration on to the ILM. Women comprise approximately 67% of patients with idiopathic macular holes or impending holes.[1] Most cases present with visual distortion and reduction of visual acuity to the level of 6/60.[1],[2] Once fully established, these lesions usually do not progress. Bilateral, full thickness macular holes occur in 3-31% of patients.[3],[4] Removal of ILMs is a useful surgical approach to close an idiopathic macular hole.[5] Because of the difficulty faced by us in removal of ILMs, we followed a technique for staining the ILM with a solution of indocyanine green (ICG-Pulsion�, Germany) to facilitate the removal of ILMs in eyes with idiopathic macular hole. It is known that surgical intervention for stage 2 (Johnson and Gass classification[1]) macular holes leads to significantly better vision at 6 months after surgery in comparison to natural history.[6] The aim is elimination of the anteroposterior and tangential traction that initially creates and later maintains the hole.

This study aimed to assess the surgical ease of ILM peel using staining with ICG in macular hole surgery. The underlying hypothesis of this study is that removal of the ILM may remove tangential traction from the macular hole and thus aid in its closure. The elasticity of the retina increases post-ILM-peel and helps close the hole (Madreperla SA, Geiger GL, Funata M, de la Cruz Z and Green WR. Clinicopathological correlation of a macular hole treated by cortical vitreous peeling and gas tamponade. (Ophthalmology in Press).

 Materials and Methods



Eighteen eyes of 18 consecutive patients presenting at the Retina Service of our Centre with idiopathic macular hole (stage 2 or stage 3) underwent macular hole surgery by one surgeon (AK), from August 2000 through May 2001, as described below. Stage 1 holes were excluded from the study and kept on a close follow-up every 4 weeks. None of the patients had stage 4 hole and epiretinal membrane was not seen in any of the eyes. The size of macular hole was individually measured with reference to optic disc size (1500μm approximately).

The surgical technique included a standard three-port pars plana vitrectomy. Complete posterior cortical vitrectomy was followed by careful identification, engagement, elevation and removal of the posterior cortical vitreous layer in all 18 cases. Sterile 0.5% ICG (approximately 0.1 ml of 5 mg per ml of distilled water) was squirted over the macula. The vitrectomy ports were temporarily plugged for about 2 minutes. This much time was usually required for ILM to take the stain (personal experience). The excess ICG was aspirated from the vitreous cavity with a vitrector. Once the media clarity improved we proceeded with the maculorhexis, as described below.

An optimal starting point for ILM-peel was chosen within the arcade vessels but remote from the fovea at approximately 5 o'clock, for surgical convenience. The site was chosen to lie outside the maculopapular bundle. Tano's diamond dusted membrane scraper (Synergetics, Inc., USA) was used to raise a small ILM flap. In this way, we avoided engaging the neurosensory retina. The ILM flap was grasped with end-opening forceps (Grieshaber, Alcon Fort Worth, TX, USA) and a "rhexis" (smooth-edged continuous tear) was created by slowly tearing the ILM in a circular motion, concentric with the fovea, with the direction of force following the natural course of the nerve fibres [Figure:1]. Most of the time the ILM was removed as a single piece, but if the tear was incomplete, the ILM was simply re-grasped at the new edge, and the rhexis was resumed. If the fovea was noted to be under traction during this procedure, the peeling force vector was redirected slightly toward the fovea until the traction had resolved, and the tearing was then continued in a similar fashion. When working close to the fovea, we kept the hole under constant observation [Figure:2]. The ILM was peeled so as to cover as much of the area of the macula as possible (minimum size of two-disc diameter, 3000 microns).

The small circle of ILM (operculum), if still remaining over the foveola, was not disturbed. The peripheral retina was examined for any retinal breaks using the wide-angle viewing system with scleral depression. The vitreous cavity was filled with a 14% non-expansile volume of perfluoropropane (C3F8) gas and the sclerotomies were closed with 6-0 vicryl suture. The gas bubble, placed inside the eye, provided a long-acting splint to the macular hole (this is known to increase the chance of successful surgery).

The patients were advised to follow strict facedown positioning for one week. Such positioning was advised not only during the day, but also during the night. The intraocular pressure (IOP) was measured with an applanation tonometer at 6 hours postoperatively. Oral acetazolamide 250 mg was required only in one patient due to high IOP (28 mm of Hg); this stabilized to normal in three days (the patient was discharged thereafter) and the oral acetazolamide was withdrawn at first follow-up visit. All patients, except the one with raised IOP at 6 hours, were discharged from the hospital on the first postoperative day.

 Results



Our results [Table:1] show that removing the ILM by maculorhexis appears to significant improve the postoperative visual acuity without the need for further medical adjuvants. Fifteen of 18 macular holes (83.33%) closed after the primary macular hole surgery. Anatomic success was poor in larger holes.

Final visual acuity improved in 15 (83.33%) of the 18 eyes at 3 months. All the eyes showed improvement in vision where the hole was anatomically closed. Visual acuity did not improve in eyes with open macular hole after surgery. Five (33.3%) of 15 eyes with anatomical closure had improvement to 6/18 or better, and in 9 (60%) of 15 patients improvement of vision was greater than or equal to 2 Snellen's line. The duration of the macular holes varied from 4 months to 2Z\x years. The duration did not affect the final outcome in our series of patients.

The macular hole in all 10 eyes equal to or less than 400μm closed anatomically and showed improved vision over the preoperative vision. In the remaining 8 eyes with macular hole size >400μm, the hole did not close in 3 eyes and vision did not improve in any of them. Epiretianl membrane (ERM) was not seen in any of these eyes.

 Discussion



Ultrastructural studies[7] have demonstrated that the removed ILM is lined by myofibroblasts and fibrocytes, accounting for the tangential traction. The removal of the ILM may remove tangential traction from the macular hole and thus aid its closure. The elasticity of the retina increases post-ILM-peel and helps close the hole. After the ILM peel gliosis is stimulated. There was no evidence of retinal structural or functional deterioration over 3 months of follow-up in this series. This is evident by the visual-acuity results. None of our patients had any iatrogenic retinal break during the surgery. There were no other complications.

ILM peeling significantly improves visual and anatomic success in all stages of recent and chronic macular holes.[5] Our report reiterates that ILM peeling should be performed in all macular holes. Attempts to peel the ILM may represent a quantifiable "dose" of therapeutic glial proliferation stimulus. The ILM peeling was performed in one-step in most of our cases. This was important in reducing the risk of mechanical or phototoxic macular injury. Moreover, the starting point of maculorhexis should not overlie the papillomacular bundle. With optimal visualization and procedural experience, the manouvere should become predictable and atraumatic. However, in order to avoid undue trauma to the inner retinal elements, the excessive effort to peel ILM should be avoided if the ILM is not readily removable.

Since the natural history of macular hole is poor, and spontaneous closure of the hole occurs in only about 5%,[8] the surgery is important. The two main components of treatment of full thickness macular hole were the relief of all vitreo-retinal traction and intraocular tamponade. The visual outcome improves if ILM peeling is also performed along with posterior cortical vitrectomy and long-term intraocular gas tamponade.[5]

The surgery itself contributes only partly to the success. The patient's ability to position his/her head properly following surgery is absolutely critical to provide the best chance for long-term macular-hole closure with improved vision.[9] Assuming a face down position for most part of the time for the first two weeks following surgery permits the bubble to float to the back of the eye and maintain gentle pressure on the macular hole. This keeps the hole completely closed and encourages new tissue to grow across the hole, providing a permanent seal. Presumably, the elasticity of the retina increases post-ILM-peel and helps close the hole. Proliferation of Muller cells causes a centripetal contraction of the hole with eventual closure (the reverse gliosis effect due to ILM peel).[10]

Larger size of macular hole was associated with worse postoperative visual acuity throughout the study and even anatomical success (closed macular hole) could not be achieved in three cases with large (> 400 μm) macular holes. The final visual acuity was better in cases with better preoperative visual acuity. While the results are encouraging a larger prospective, randomized, multicentric case-control trial would be needed to confirm these initial findings.

References

1Johnson R, Gass J. Idiopathic macular holes: Observations, stages of formation, and complications for surgical intervention. Ophthalmology 1988;95:917-24.
2Morgan CM, Schatz H. Idiopathic macular holes. Am J Ophthalmol 1985;99:437-44.
3McDonnel PJ, Fine SL, Hillis AI. Clinical features of idiopathic macular cysts and holes. Am J Ophthalmol 1982;93:777-86.
4Yoeda H. Clinical observation of a macular hole. Acta Soc Ophthalmol Jpn 1967;71:1723-36.
5Brooks HL Jr. Macular hole surgery with and without internal limiting membrane peeling. Ophthalmology 2000;107:1939-49.
6Kim JW, Freeman WR, Azen SP, El-Haig W, Klein DJ, Bailey IL. Prospective randomized trial of vitrectomy or observation for stage 2 macular holes. Am J Ophthalmol 1996;121:605-14.
7Smiddy WE, Green WR, Michels RG, de la Cruz Z. Ultrastructural studies of vitreomacular traction syndrome. Am J Ophthalmol 1989;107:177-85.
8Guyer DR, de Bustros S, Diener-West M, Fine SL. Observations on patients with idiopathic macular holes and cysts. Arch Ophthalmol 1992;110:1264-68.
9Sjaarda RN: Macular Hole. Intr Ophthalmol Clin 1995;35:105-22.
10Madreperla SA, Geiger GL, Funata M, de la cruz Z, Green R. Clinicopathological correlation of a macular hole treated by cortical vitreous peeling and gas tamponade. Ophthalmology 1994;101:682-86.