O R I G I N A L A R T I C L E

Ablation Pit Treatment For Corneal Decompensation

Historically, the management of cloudy, decompensatedcorneas centered around replacement of corneal tissuewith either a through-and-through or partial-thicknessreplacement. This article presents a technique that is aradical departure from prior methods.

A B S T R A C T

ANN OPHTHALMOL. 2006;38 (1) ....................................................21

DALJIT SINGH, MS, DSc

R E P R I N T S Dr. Daljit Singh, MS, DSc, c/o Fugo Eye Institute, 100 W. Fornance, Norristown,PA 19401.

Dr. Singh is from the Dr. Daljit Singh Eye Hospital in Amritsar, India.

The author has stated that he does not have a significant financial interest orother relationship with any product manufacturer or provider of servicesdiscussed in this article. The author also does not discuss the use of off-labelproducts, which include unlabeled, unapproved, or investigative products ordevices.

Submitted for publication: 12/30/05. Accepted: 1/18/06.

Annals of Ophthalmology, vol. 38, no. 1, Spring 2006© Copyright 2006 by ASCO All rights of any nature whatsoever reserved. 1530–4086/06/38:21–24/$30.00. ISSN 1558–9951 (Online)

It is a long story that began in November 2000. Beforestarting a glaucoma operation, I injected lignocaine sub-conjunctivally near the limbus at 10 o’clock. The sameinstant, I noticed a transparent vessel momentarily swellat 3 o’clock, about 1 mm from the limbus. The bellsrang in my mind. Over the next few weeks, I chartedlymphatics in glaucoma cases by pushing a drop of Try-pan blue under the conjunctiva (1). One day, I foundthat injecting into the extreme periphery of the corneabest charted the lymphatics. These lymphatics wereseen to arise from all around the cornea as fine channelsperpendicular to the limbus that joined each other andformed many sacculated and non-sacculated channelsrunning parallel to the limbus, and finally ended as twosingle channels, one at the upper fornix and another atthe lower fornix (2). At the 2001 American College ofEye Surgeons meeting, I showed these lymphatics andsuggested that they drained the uveo-scleral outflow andleakage from the aqueous veins and acted as flooddrains after filtration surgery.

My curiosity led me to a slit-lamp search for lym-phatics. I then was able to visualize and photographtransparent channels running parallel to the limbus. Oneday I struck gold. The observation was on a patient withsome pigment around the limbus. The pigment neatlyoutlined the lymphatics and Palisades of Vogt (Fig. 1). Icould see the channels all around the limbus. The limballymphatics showed anastomosis toward the conjunctivaside; however, their somewhat obscure endings alongthe cornea seemed to be open.

I saw wide lymphatic rivulets (outlined by pigment)running parallel to the limbus, clearly coursing in frontof the blood vessels. I saw radial lymphatics invadingthe cornea for a considerable distance, along withtranslucent masses of bulbar spring catarrh (3).

I became convinced that a wide lymphatic networkexisted around the limbus, which had an intimate rela-tionship with the cornea. I observed small cornealabscesses and was surprised at the speed with which themyriad of inflammatory cells appeared and disappearedfrom the inflamed areas.

Looking at some cases of arcus senilis, I was fascinatedto find a network of what seemed to be channels in thearcus that seemed to terminate in the area of the well-known “lucid interval.” These channels were not visiblein completely transparent cornea or in a totally opaquecornea. I examined a young boy with keratoglobus and acentral corneal opacity. It revealed a typical network of channels as I saw earlier in arcus senilis. Channels are also seen in many cases of striate keratitis aftercataract surgery. On optical section, the channels appearmostly in the middle layers of the cornea. I concludedthat there is a generous network of lymph pseudo-channelsthroughout the cornea. At the periphery of the cornea,the network is in intimate relationship with the ends ofvascular capillaries. That is the conduit system by whichthe inflammatory cellular response is activated in secondsor minutes, and explains how infection can travel so fastin the cornea.

I examined a corneal abscess in the lower part of thecornea, running parallel to the limbus in a place thatcould be the “lucid interval,” if arcus senilis were pre-sent. In spite of our best treatment, the abscess traveledas an arc along the limbus with devastating speed. In 24hours, the reaction had traveled to 12 o’clock position.This opened my mind to the possibility of the “lucidinterval channel” being an important conduit for cornealmaterial transport. What is the histo-anatomy of these

channels? My guess is that they are sinusoidal channelsthat eventually drain into the conjunctival lymphatics.However, the network of channels that I saw in thecornea up to this time was relatively gross. There had tobe a finer network that existed everywhere and must bepart and parcel of this network. I found such a networkin cases of noninfective keratitis of many kinds. The“sands of Sahara” actually presented the same pattern.The semi-opaque corneal tissues seemed to outline thefiner channels.

I believe that wherever there is fluid, there is fluidmovement. The cornea is no exception. The endotheliummost likely regulates the fluid closest to it. The rest movesforward, irrigates the cornea from inside out, and movesout of the anterior corneal layers into the pericorneallymphatics. Oxygen, on the other hand, travels from thesurface inward. Corneal edema reduces both of theseprocesses and inflicts further damage.

Concurrently, I was actively using the Fugo PlasmaBlade for many applications, such as capsulotomy,membranectomy, pupilloplasty, strabismus, and glauco-ma surgery. I was keenly aware of the unique cutting/ablating capabilities of this tool (4). It cuts/ablates likean Excimer laser with clinically insignificant collateraldamage (5). You touch any tissue with a 100-µ-activatedFugo Blade tip and instantly the tissue around the fila-ment is turned into a plume, not unlike what is seen withthe use of Excimer laser (6).

One evening, I was suddenly struck with an insightabout the modality of operation of the Fugo Blade andwhy it would have a unique biophysical effect on thestructure of the cornea. I recalled the scanning electronmicrograph images from the Storm Eye Institute (Uni-versity of South Carolina, Columbia, SC [7]) and thehistographs of Dr. Herb Kaufman at Louisiana StateUniversity, New Orleans, LA), wherein the ablationwalls of a Fugo Blade incision were pristine clean andnormal (8). If we used a standard electrocautery, theincision wall is burned, as seen on histological section.Therefore, if I used the Fugo Blade to make pits verti-cally into the corneal structure, then the walls of the pitswould be like an elevator shaft, with the corneal lym-phatic channels presenting like open elevator doorwaysthrough which lymph could pour into this Fugo Bladepit. On the other hand, a standard electrocautery wouldcause the elevator-door opening to be melted and sealedshut. If we stabbed the corneal with a blade, the force ofpushing on the blade would cause the walls of the inci-sion pit to be squashed or compressed inward, therebycrimping the doorways of the elevator shaft shut. Recallthat the Fugo Blade ablates in a truly resistance-freefashion.

ANN OPHTHALMOL. 2006;38 (1).....................................................22

Figure 1—Limbal and conjunctival lymphatics. At thecorneal end, the lymphatics are straight, running parallel withthe Palisades of Vogt, whereas they anastomose freely underthe conjunctiva.

I thought if the fluid flow from the deeper to thesuperficial layers of the cornea could be sped up bymaking corneal pits with a Fugo Plasma Blade, a furtheroutward drainage of the moving fluid by the lymphaticscould reduce corneal excess fluid with Fugo Blade abla-tion pits into the corneal surface. Thereby, the hydrationstatus of the cornea would be reduced by allowingexcess water to escape out of the Fugo Blade ablationpit in the surface of the cornea.

In an instant, the thought flashed before my mindto treat water-logged corneas by drainage of excessfluid with Fugo Blade ablation pits into the cornealsurface. Then I saw an 85-year-old, one-eyed patientwith full-blown corneal decompensation (Fig. 2) whobegged me to help him. Unfortunately, donor corneasare difficult to obtain in our area. This man had comefrom more than 1000 miles away. I had implanted an iris claw lens 18 years earlier and he had goodvision for more than 17 years. I had no corneasavailable, but only my theory on Fugo Blade surfacepit ablation. It was clearly explained to the patientand his son that he would be the first ever patient forthis therapy. If the treatment failed, it would stillallow corneal grafting when available. The patientjumped at this opportunity. A series of 400-µ-deeppits were made in the edematous cornea with a 100-µ tipon the Fugo Blade outside of the visual axis. Theprocedure under topical anesthesia took 3 to 4 minutesto complete without complications. A day later, therewas a glimmer of hope—the cornea looked slightlybetter.

Ten days later, the patient felt much more confident infinding his way about (Fig. 3). Endothelial cells could beseen as more than 450/mm2 in one clear area. I pre-

scribed hypertonic saline and antibiotics, hoping that hiscondition was treated. However, he did turn up after 1.5months. I was happily surprised to see his transparentcornea (Fig. 4). His corrected vision was 6/12 and hisendothelial cell count had gone higher than 800 cells.His next visits came after 12 and 18 months. His satis-factory condition remained unchanged.

Meanwhile, I have treated nearly two dozen additionalpatients who had varying degrees of corneal decompen-sation in aphakia and pseudophakia. Nearly everypatient showed at least some degree of improvement. In about one-third of these patients, the recovery wasimpressive subjectively as well as objectively (Figs. 5and 6).

ANN OPHTHALMOL. 2006;38 (1).....................................................23

Figure 2—An 85-year-old patient. Hypertonic saline instilledevery 5 minutes for 2 hours could clear the cornea only asmuch as evident here.

Figure 3—The cornea of the same eye 10 days after makingcorneal pits with a Fugo Blade. Hypertonic saline wasinstilled three times at 5-minute intervals before taking thisphotograph.

Figure 4—The eye had cleared in 1.5 months. The correctedvision was 6/12. The spots on the cornea are the points where400-µ-deep corneal pits were made with a Fugo Blade.

The results are dependent on the extent of endothelialdamage, the amount of corneal edema, and the integrityof the corneal channels and limbal and conjunctivallymphatics. When a diseased epithelium is removed,there may occasionally be a problem with its orderlyregrowth.

A future report with longer follow-up on morepatients will present data with statistical analysis. This isa preliminary report that will be presented at the urgingof colleagues to whom I have shown this preliminarydata because this technique is so counterintuitive to pre-sent-day thought and therapy. The objective of the pre-liminary report is to allow colleagues to consider thisnovel approach to this old, difficult problem. Not onlyare corneas in short supply in most areas of the world,but many corneal transplants are prohibited by religiousdoctrine.

REFERENCES1. Kent C. Revealed: The eye’s lymphatic system. Ophthalmol Manag

2002;5:144.2. Bethke WC. A new clue to lymphatic drainage. Rev Ophthalmol.

2002;3:12.3. Singh D, Singh RSJ, Singh K, et al. The Conjunctival lymphatic

system. Ann Ophthalmol 2003;2:99–104.4. Winn CW. Broad applications deen for plasma blade. Ocular Surg

News 2001;11:45–46.5. Izak AM, Werner L, Pandey SK, Apple DJ, Izak MGJ. Analysis of

the capsule edge after Fugo Plasma Blade capsulotomy, continuouscurvilinear capsulorhexis, and can-opener capsulotomy. J CataractRefract Surg 2004;12:2606–2611.

6. Sabbagh LB. The leading edge: Harnessing electrons for a faster,smarter incision. Eyeworld 1998;4:86.

7. Singh D, Singh RSJ. Application of the Fugo Blade. In: Wilson ME,Triverdi RH, Pandy SK, ed. Pediatric Cataract Surgery: Techniques,Complications, and Management, 1st ed. Philadelphia, PA, Lippin-cott Williams & Wilkins, 2005, pp. 97–100.

8. Peponis E, Rosenbery P, Reddy SV, et al. The use of the Fugo blade incorneal surgery: a preliminary animal study. Cornea, 2006;25:206–208.

ANN OPHTHALMOL. 2006;38 (1).....................................................24

Figure 5—A 64-year-old patient with corneal decompensationand bullae formation 18 years after iris claw lens implantation.The patient had remained untreated for more than 1 year.

Figure 6—The same eye 2 months after epithelium removaland drainage with Fugo Blade corneal pits, visible as multiplespots on the corneal periphery. The corrected vision was 6/6.