Ophthalmi pinion1Vol 1 No 1 2018

Volume 1 No 1 - 2018

Ophthalmi pinionCME Ophthalmology Insights

In thIs Issue:• ethics: ROP - medico-legal considerations• Making sense of MIGs• Medial Canthal tumours - diagnosis and

management• Lamellar Corneal surgery CPD Accredited

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Ophthalmi pinion3

Editorial

Vol 1 No 1

Editor: Dr Garry RoseProduction Editors: Ann Lake Publications Ann Lake, Helen GonçalvesDesign: Jane GouveiaEnquiries: Ann Lake PublicationsTel: 011 802 8847Fax: 086 671 9397Sponsor: Adcock Ingram HealthcareEmail: lakeann@mweb.co.za

DisclaimerThe content contained in this publication is provided in the interests of continuing medical education and is intended to stimulate and promote debate by disseminating informed opinions on the latest medical advances and treatments in ophthalmology. No suggested test or procedure should be carried out unless, in the reader’s judgement, its risk is justified. Because of rapid advances in the medical sciences, we recommend that the independent verification of diagnoses and drug dosages should be made. Discussions views, and recommendations as to medical procedures, products, choice of drugs, and drug dosages are the views of the authors. The views expressed by the editor or authors in this newsletter do not necessarily reflect those of the sponsors or publishers. The sponsors, publishers and editor will not be liable for any damages or injuries of any kind arising from the use or misuse of information provided in this publication and do not support the use of products for off label indications. The views and opinions expressed in these articles were in no way influenced by Adcock Ingram.

Dr Garry RoseOphthalmic Surgeon

Chelmsford Medical Centre, St Augustine’s Hospital, Durban

Sponsored in the interests of Continuing Medical

Education by:

In this issue:

EditorialDr Garry Rose 3

Medico-legal considerations in Retinopathy of Prematurity (ROP) Dr Linda Visser

4

Making Sense of MIGS: Their position in current surgical IOP-lowering proceduresProf Grant McLaren

6

Diagnosis and Management of Medial Canthal TumoursDr Brian van Onselen

9

Lamellar Corneal Surgery: A journeyDr Malcolm Carey

11

I would like to welcome you to the first edition of Ophthalmic Opinion, which I hope will become a regular 3-monthly read for you. It is sponsored by Adcock Ingram, who have shown renewed interest in Ophthalmology CME, and their willingness to fund this newsletter is gratefully noted. Having said that, it must be emphasized that Adcock Ingram has no influence on editorial policy, or on content of the articles, or on choice of contributors.

You may wonder why the name Ophthalmic Opinion was chosen. It is hoped that, beyond transmission of information in the various articles, ophthalmologists will contribute their opinions. This is very valuable to all. Consider the tea-times and lunches at our congresses when discussion between colleagues leads to the exchange of so much meaningful information in an informal milieu. In this spirit, in future issues, there will be a section devoted to your opinions, and the hope is that this will be well-used. We look forward to receiving your comments, which can be emailed to opinions.ed@gmail.com.

There are four excellent, useful articles in this issue, and their authors need no introduction. I have been truly impressed by the willingness of our colleagues to contribute when asked, and this is typical of the generosity of spirit, which I have noted over my long association with South African ophthalmology.

A thought for the day: while we, as ophthalmologists, are not directly and professionally involved with the major problems of our time (global warming, human rights abuse, poverty, pollution and nuclear disarmament) we can use our influence where we are able. Have you considered how, on a list of cataract operations, the yield of a few grams of lens material is supported by mountains of packaging and waste? Perhaps we should look critically at this, and perhaps it’s time for the companies we deal with to use their considerable ingenuity to address this imbalance.

Have you considered how, on a list of cataract operations, the yield of a few grams of lens material is supported by mountains of packaging and waste?

Ophthalmi pinion 4 Vol 1 No 1 2018

he sudden increase in ROP medico-legal cases has prompted some medical insurance companies to ask ophthalmologists to declare whether or not they are involved in

ROP screening and if so when they qualified and what their experience in ROP screening is. Depending on the response, their levies might be increased. Where will this lead to? Is this warranted? Will it cause ophthalmologists to “opt out” of doing ROP screening?

Having been involved in a number of cases in which claims were brought against neonatologists, ophthalmologists or Provincial Departments of Health, I do not believe increasing the levies of ophthalmologists doing the screening is warranted. It could potentially exacerbate the problem if doctors refuse to screen, and should therefore be challenged. Of 30 cases I have been involved with, the majority of claims have been brought against Provincial Departments of Health, and mostly (80% of the time) against neonatologists only, with only 20% of claims including both the neonatologist and ophthalmologist. Some of the latter have been successfully challenged in court. If you are screening for ROP, how can you limit your risk of ending up in court?

Firstly, as the majority of claims are primarily aimed at our neonatology colleagues, but lawyers like to cover all bases and therefore include the ophthalmologist in the summons, communicate with your colleagues regarding their role in the primary prevention of ROP. The issue of oxygen supplementation and monitoring is controversial, but remains the only alterable or avoidable risk factor and one exploited by lawyers in the court. Following the publication of the NeOProM study results in 2014,1 guidelines suggest optimal saturation levels of between 90% – 95% (where previously they were between 88% – 92%). There will be times when these cannot be maintained for various reasons and neonatologists will not be negligent in keeping very ill infants on higher saturations in order to save their lives – these reasons need to be properly documented in the notes though. In cases where saturation levels are kept above 95% on supplemental oxygen therapy

without good reason and ROP develops, leading to visual impairment, a successful defence is near impossible.

Failing to refer babies at risk for screening (secondary prevention) is another major rea-son for court cases. Who to refer and when to refer is not too complicated. The courts will refer to specific guidelines. The national guidelines are quite old (2002) but are of-ten still cited. Recent guidelines published in the SAMJ (2013)2 and endorsed by OSSA, USANA and SAVRS, state all babies born <32 weeks’ gestational age OR weighing <1500g at birth must be screened irrespective of oth-er risk factors and babies with a birth weight between 1500g and 2000g with additional risk factors, of which inappropriate oxygen supplementation is the most important, must also be screened. The national guideline doc-ument uses <33 weeks’ post-conceptual age OR <1250g birth weight. Terminology used can be confusing. Gestational age and post-menstrual age are synonymous but post-con-ceptual/post-conceptional age is estimated to be approximately 2 weeks less than post-menstrual age, and should not be used. The national guideline document probably meant to use postmenstrual age and not post-con-ceptual age, an error also made in the SAMJ article when discussing the timing of the first screening visit. It should be at either 4 to 6 weeks of chronological age or 31 weeks of postmenstrual age (not post-conceptional age as per the article), whichever comes lat-er, but no later than 37 weeks’ postmenstrual age. If the ROP screening is to take place af-

ter the infant is discharged from the neona-tal unit, it is important for the neonatologist/ paediatrician to make a note of the screening visit and have the parents sign the note to acknowledge this – all too often, if nothing is noted, parents claim that they were never informed to take their infants for screening.

Doing the screening is the responsibility of the ophthalmologist. Binocular indirect ophthalmoscopy is the gold standard. If you are unsure of your own abilities in examining the fundi of premature

infants, do not undertake ROP screening. In larger centres it is not necessary for all ophthalmologists to do ROP screening and a colleague, who is better trained should be asked to assist. In smaller towns, with only 1 practicing ophthalmologist, the responsibility will be yours and you should equip yourself as best as possible to do the job. It is not difficult to examine the fundi of premature babies if their pupils are adequately dilated as they rarely fight back. It is best to examine them in the neonatal unit in case they develop apnoea, with a nurse acquainted with swaddling techniques and gently keeping the infant immobile with the aid of oral sucrose or a pacifier.

Make sure the eyes are adequately anaesthetised, use a small paediatric (infant) wire speculum and a 28 or 30 dioptre lens, and indent 360 degrees. When examining the fundus with a 30 dioptre lens, if you are centred on the disc, your field of view, without moving your head, is approximately that of zone I. Using a 28 dioptre lens your field of view is only slightly smaller than zone I. To indent, use a paediatric lens loop (Figure 1). It follows the curve of the eye and is slender enough to easily slide in the fornices. Make sure you are able to see the ora when you indent. On initial examination, look carefully at the vessels emerging from the disc for venous dilatation and/or arterial tortuosity before indenting as indentation decreases the vascular dilatation.

Note if there is plus (Figure 2) or pre-plus disease. Remember when diagnosing plus or pre-plus disease to look at the posterior vessels and not the vessels leading up to the ridge. Note the stage and zone of the disease nasally and temporally and describe any other features such as haemorrhages, vitreous condensations, gliosis/fibrosis, temporal dragging, “popcorn” vessels (usually a sign of regression), and vascularisation beyond the initial line. It is best to make detailed notes or use a template (Figure 3).

Medico-legal considerations in Retinopathy of Prematurity (ROP)

Figure 1. Paediatric lens loop

Dr Linda Visser, Academic Head of Department, Senior lecturer, Ophthalmology Department, University of KwaZulu-Natal

Ophthalmi pinion5Vol 1 No 1 2018

Depending on your findings, babies will either need treatment (Type 1 ROP), follow up (Type 2 ROP, early ROP, no ROP or regressing ROP) or discharge (fully vascularised). NEVER discontinue screening unless you are sure the retina is fully vascularised or vascularised into zone III without prior zone I or II ROP, ROP has fully regressed or postmenstrual age of 45 weeks has been reached and no type 1 or type 2 ROP is present. If you are not sure, rather review one more time. The main reason for claims against ophthalmologists to have been conceded, is patients being discharged too soon and subsequently developing ROP. When asking parents to bring babies back regularly, explain to them why this is necessary. Parents are more likely to comply if they understand why they need to return so often.

In patients with treatable (type 1) ROP, treatment should be given within 48 – 72 hours. The scope of this article does not allow for an in-depth discussion on treatment. Options include laser photocoagulation of the anterior non-vascular retina or the use of anti-VEGF injections or a combination of the two. The BEAT-ROP trial3 showed better outcomes for anti-VEGF (avastin) treated eyes with zone I disease but no difference for zone II disease. As there still remains a concern regarding systemic side effects (VEGF is important in organogenesis), some experts caution against the use of anti-VEGF drugs in all cases, at least until longer follow up of these children has been

completed. Currently, we use avastin for all cases of aggressive posterior ROP (AP-ROP) or Type 1 disease in zone I or posterior zone II. For Type 1 ROP in mid- or anterior zone II laser photocoagulation still has very good outcomes. Timing of the avastin injection is crucial - given late it can lead to progression of ROP to stage 4 disease rather than regression as hoped for - possibly explained by the fragile and constantly changing equilibrium existing between connective tissue growth factor and vascular endothelial growth factor in these eyes, and the triggering of the angio-fibrotic switch by the administration of anti-VEGF. It is also important to remember that vascularisation progresses much slower after timeous anti-VEGF treatment and infants therefore need to be followed up for a much longer time (often beyond 60 weeks’ postmenstrual age) to pick up late recurrences.

Stage 4 and 5 disease should be referred for a lens-sparing vitrectomy to a vitreoretinal surgeon with experience in this type of surgery.

Following the above simple and practical advice should be enough to avoid legal complications.

References available on request.

Treatment must be initiated for Type 1 ROP:

Zone I ROP Any stage with plus disease

Zone I ROP Stage 3, no plus disease

Zone II ROP Stage 2 or 3 with plus disease

Suggested follow-up schedule for less severe findings

1 week or less for follow-up

• Type 2 ROP• Stage 1 or 2 ROP in zone I without plus• Stage 3 ROP in zone II without plus

1 - 2 weeks follow-up • Immature vascularisation in zone I (no ROP)• Stage 2 ROP in zone II without plus• Regressing ROP in zone I

2 weeks follow-up • Stage 1 ROP in zone II • Regressing ROP in zone II

2 - 3 weeks follow-up • Immature vascularisation in zone II (no ROP)• Stage 1 or 2 ROP in zone III• Regressing ROP in zone III

ROP Screening form

Date booked for examination___________ Hospital booked at________________

Name______________________________ Hospital Nr ______________________

Date of Birth_________________________

HIV - Exposed/ unexposed/unknown Sex _____________________________

Birth weight (grams) __________________ Multiple birth (1,2,3)_______________

Gestational age at birth _______________ Growth at birth- AGA/SGA/LGA

Duration of Oxygen: IPPV ___________ CPAP____________ Nasal O2_________________

Indication for ROP screening in this patient: please tick appropriate box.

- weight < 1500g

- gestational age < 32 weeks at birth

- weight 1500- 2000 g with high risk (as adjudged by referring neonatologist)

Examination:

Date: _________________Initials examiner: ___________ Current Age __________________

Anterior segment: _____________________________________________________________ Fundus:

Stage: Stage:

Plan:

Figure 2. Standard published photograph for plus disease. Plus disease is defined as venous dilatation and arterial tortuosity of the posterior vessels equal to or greater than the standard published photograph (at least 2 quadrants).

Figure 3. Template for documenting ROP screening findings

Ophthalmi pinion 6 Vol 1 No 1 2018

Making Sense of MIGS: Their position in current surgical IOP-

lowering procedures

ver the last quarter century or so the management of open- angle glaucoma has included topical medical therapy with or without laser

trabeculoplasty. Conventional filtration sur-gery has been reserved for advanced and rapidly worsening disease. The glaucoma treatment paradigm reserved surgical pro-cedures for later in the disease given their

reputation for short and long-term morbidi-ty. New topical medications resulted in a declining rate of glaucoma surgery. Howev-er, topical therapy demands scrupulous compliance for the therapy to be effective in preventing or delaying progression of glaucoma. Once the drop regimen exceeds one bottle the compliance rate falls off rap-idly. Glaucoma surgical devices (Baerveldt, Ahmed and Molteno) were indicated for re-

fractory glaucoma (defined as medically uncontrolled with prior failed surgery or high risk for surgical failure).

The recent advent of a new class of procedures, termed micro-invasive or minimally invasive glaucoma surgery (MIGS), has invigorated the debate around earlier surgical intervention in glaucoma treatment. Designed to improve the safety of surgical intervention for glaucoma, most MIGS procedures enhance physiologic outflow and target a different patient population. MIGS is more of an alternative to medical therapy seeking to address adherence challenges, adverse events, and quality-of-life (QOL) issues associated with topical medications. Thus, MIGS devices are often used earlier in the glaucoma treatment algorithm.

A previously proposed definition lists 5 cardinal features of MIGS:• An ab interno micro-incisional

approach, minimal trauma to and disruption of normal anatomy and physiology with devices that exhibit a high level of biocompatibility

• Demonstrable intraocular pressure (IOP) lowering

• Extremely high safety profile,• Rapid recovery. This then excludes

procedures like deep sclerectomy/non penetrating glaucoma surgery, ab externo viscocanalostomy and canaloplasty, three operations fairly routinely performed in South Africa. Similarly the ab interno gelatin microstent (Xen) can’t be classified in the MIGS category by this definition. By broadening the definition of MIGS too widely, one runs the risk of creating an overly heterogenous group of procedures with wide degrees of IOP lowering and risks.

• The key characteristic of MIGS must be that no bleb is created and that the anatomy and physiology of the drainage pathway is minimally disrupted.

The MIGS procedures therefore can be divided into the ab interno varieties: Hydrus, Trabectome, iStent and iStent

Table 1: Procedures or devices which do and don’t involve the conjunctiva

Technique/DeviceDrainage Route & Mechanism of IOP Reduction

Conjunctiva involved?

Published randomised controlled trial evidence?

Trabectome (NeoMedix)

Via Schlemm’s canal: Exci-sion of trabecular meshwork

No No

iStent (Glaukos)Via Schlemm’s canal: Bypass of trabecular meshwork

No Yes

iStent Inject (Glaukos)

Via Schlemm’s canal: Bypass of trabecular meshwork

No No

Hydrus (Ivantis)Via Schlemm’s canal: Bypass of trabecular meshwork

No Yes

AbIC: Ab Interno Canaloplasty with iTrack (Ellex)

Via Schlemm’s canal: Dila-tion of trabecular meshwork

No No

Cypass (Transcend) Via supra-choroidal space No No

iStent Supra (Glaukos) Via supra-choroidal space No No

Endo-cyclophotoco-agulation ‘Endo-Di-ode’

Cyclo-destructive No No

Microshunt (InnFocus)To sub-tenons/sun-conjunc-tival space

Yes No

Xen (Aquesys/ Allergan)

To sub-tenons/sun-conjunc-tival space

Yes No

Prof Grant Mclaren, Wits Donald Gordon Medical Centre and St John Eye Hospital,Division of Ophthalmology, University of Witwatersrand

Ophthalmi pinion7Vol 1 No 1 2018

inject, Cypass, iStent Supra and ECP (endocyclophotocoagulation) and the ab externo procedures: Microshunt (Innfocus) and the locally familiar Xen (gelatin microstent).

These latter 2 MIGS procedures are bleb forming.The non-bleb forming MIGS have only modest IOP lowering ability and generally employed in combination with phaco surgery. Their IOP lowering is limited by the episcleral venous pressure (EVP). The pressure will never be less than 15mmHg.Reducing the number of medications in a patient with early to moderate glaucoma. Safety is critical in motivating MIGS intervention and risk is limited as these procedures are mostly done in combination with phaco surgery.

Bearing in mind the well established fact that phaco alone can reduce IOP by 4mmHg this procedure is certain to obtain an acceptable reduction in pressure.

A thought to ponder the application of MIGS:

“MIGS is to Phaco as Toric Lenses are to IOLs.”

The advantages and limitations for iMIGS are listed in Table 2.

Nonimplant MIGS• Trabectome (NeoMedix). Electro-

cautery, irrigation, and aspiration are used to selectively ablate the trabec-ular meshwork and the inner wall of Schlemm’s canal to allow aqueous free access to the canal and its collector channels (FDA approved in 2004).

• Kahook Dual Blade (New World Med-ical). This relatively inexpensive sin-gle-use disposable handpiece employs 2 parallel blades to remove a strip of trabecular meshwork to improve out-flow, without need for an expensive electrocautery or irrigation/aspiration system.

• Gonioscopy-assisted transluminal tra-beculotomy. GATT is a minimally inva-sive ab interno circumferential trabec-ulotomy (see Fig. 1) that is performed through two 1.0-mm corneal incisions and employs either a microcatheter, 5-0 Prolene suture, or TRAB 360 handpiece (Sight Sciences). After cannulation, the entire trabecular meshwork is unroofed.

• Ab interno canaloplasty (ABiC). The procedure, performed through a single self-sealing clear corneal incision, in-volves 360-degree viscodilation of the canal using either the iTrack microca-theter (Ellex) or the VISCO360 (Sight Sciences) handpiece and an ophthalmic viscoelastic device inserter.

• Endoscopic cyclophotocoagulation (ECP). An endoscopic probe is inserted via a corneal or pars plana incision to ablate a selected portion of the ciliary epithelium under direct endoscopic visualisation. This process decreases aqueous production

The debate around the timing of surgical intervention will always revolve around cost of device versus the cost saving long term with fewer topical medicines. There is also the tendency to mix and match procedures like placing two I-stents on either side of a Cypass suprachroidal stent. This will require evaluation in randomised trials to

specifically show the economic benefit of using single or multiple MIGS to reduce IOP surgically and reduce the number of topical drops.

Steven L. Mansberger, MD, MPH, of the Devers Eye Institute has expressed concerns in the area of efficacy and costs. “As a glaucoma specialist, I am always interested in finding new ways of lowering pressures safely and effectively, and I applaud the investigators in this space, “he noted.

“That being said,” he added,” MIGS may be useful for some patients, but traditional

Table 2: Mild-moderate disease prevention

Schlemm’s Canal Supracoroidal Space

• Extremely high safety• Combo phaco• EVP floor• Technical skill level• IOP results modest

• Large potential space• Combo phaco• Variability dependent on healing• Technically intuitive• IOP results modest

Combined with cataract surgery - surgical intervention with modest IOP lowering justified as already in the eye with safety parallel to phaco.

Figure 1

Figure 2

Ophthalmi pinion 8 Vol 1 No 1 2018

surgeries are required for a vast majority of surgical glaucoma patients, and it is imperative that we continue to learn the in and outs of trabeculectomies and tubes in our glaucoma fellowships.” I endorse this sentiment in our context here in South Africa where we are resource strapped and need to ensure that we retain inexpensive procedures that are predictable and effective.

My procedure of choice in most patients with high pressures is the augmented trabeculectomy. By this I mean the judicious use of mitomycin C (MMC) and Avastin (bevacizumab). The Moorfields More-flow, safe surgery technique which was pioneered and presented to the world by Peng Khaw and co-workers has been a real leap forward for myself and colleagues at St John Eye Hospital. The key features of the procedure are well outlined in many publications and on the Moorfields website.

Our patients require more antifibrotic treatment than Caucasian patients in the Northern hemisphere. The concentration we routinely use is in the region of 0.4 -0.5mg/ml and applied to the sclera with 5 sponges applied for two to three minutes. An alternative is to inject 40 to 60 µg MMC peroperatively sub-conjunctivally.This 0.1 to 0.15 ml of the 0.4mg /ml using an insulin syringe. This must be combined with a scleral flap 5mm by 3mm in size with shelved wound edge at the limbus. The conjunctiva must be sutured into the cornea using preplaced juxta-limbal corneal incisions.

This is my procedure of choice in all types of intractable glaucoma. The one exception may be silicone oil induced glaucoma where emulsified oil may collect in the superiorly placed bleb with resultant

fibrosis and failure. Here I would use and inferiorly placed Baerveldt valve (preferably inferonasal) which will not attract the emulsified silicone oil. Invariably these patients are pseudophakic and the tube can be placed in the posterior chamber.

In most cases, patients with complicated and aggressive glaucomas will be ideally suited to augmented trabeculectomy. There are now publications which suggest that bleb forming ab interno gel stents (Xen) may be applied as alternative procedures to trabeculectomy. It is self- evident though that scrupulous post-op care of the bleb is vital to the short and medium term survival of the bleb in both procedures.

The key advantage of the trabeculectomy over the Xen or any other bleb forming MIGS device is the ability to needle failing blebs ab interno. Some authors like Davinder Grover from Texas suggest placing the Xen stent in the lumen of the glaucoma drainage device as a flow retardant or simply placing it, the Xen, in an adjacent quadrant to tide the patient through the immediate post op period of the ligated tube and during the hypertensive period. The real debate is about when to use MIGS alone or in combination with topical medicines and/or laser. This will involve surgeon comfort or preference combined with patients willingness to undergo surgery for IOP control alone. When cataract surgery is indicated this makes for an easier choice and ab interno MIGS can be offered to the patient.

My real concern though is the belief that these MIGS procedures are equivalent to trabeculectomy and glaucoma drainage devices.

Figure 3 above shows the likelihood of how many occasions patients undergoing cataract surgery will have glaucoma comorbidity.

The downside of MIGS in our context will always be cost. But if studies show substantial cost savings over time then the one-off cost of the device will be justified. More appealing and affordable are the gonio-assisted transluminal trabeculotomy (GATT). The trabecular canal can be deroofed internally with a microcatheter, a 5/0 Prolene suture or a TRAB 360 handpiece (Sight Sciences). Dr Grover reported on 2 GATT studies showing very good results at 2 years in dysgenic anterior segment patients and primary congenital glaucoma patients as well as adult primary open angle and secondary glaucoma patients. Pressure reductions in both groups ranged from 37% to 50% at two years follow-up. Best pressure reductions were in the adult secondary open angle glaucoma patients. The major advantage in these procedures is the preservation of the conjunctival tissues from incision and scarring allowing better outcomes if traditional surgery is required later

References1. Iqbal Ike K Ahmed MIGS. What’s in

a name. Editorial. Ophthalmology, vol.122, Issue 9, p1737-1739 September 2015

2. Vinod K et al. J Glaucoma. 2017;26(8):687-693.

3. Ferguson TJ et al. Clin Ophthalmol. 2016;10:1767-1773.

4. Gallardo MJ et al. Clin Ophthalmol. 2016;10:1931-1937.

5. Grover DS et al. Br J Ophthalmol. 2015;99(8):1092-1096.

6. Grover DS et al. Gonioscopy-assisted transluminal trabecu¬lotomy: an ab interno circumferential trabeculotomy midterm follow-up. Paper presented at: annual meeting of the American Academy of Ophthalmology; Nov. 17, 2015; Las Vegas.

7. Fellman RL, Grover DS. J Glaucoma. 2014;23(6):347-350.

8. Fellman RL et al. Opthalmology. 2015;122(12):2385-2391.

9. Ferguson TJ et al. J Cataract Refract Surg. 2017;43(3):377-382.

10. Lim KS et al. Br J Ophthalmol. 1998;82(9):1083-1089.

11. Saheb H, Ahmed IK. Curr Opin Ophthal¬mol. 2012; 23:96-104.

Figure 3

Ophthalmi pinion9Vol 1 No 1 2018

edial canthal tumours are often overlooked due to their position behind the nose-pieces of spectacles. The lesion can also be

ascribed to chronic rubbing of the nose-pieces and thus dismissed as “irritated skin”.

The medial canthal region has the least skin excess, thin subcutaneous tissue and has a characteristic form with a central depression. It is a common site for malignant skin tumours, particularly basal cell carcinoma. Other important tumours include melanoma and squamous-cell carcinoma.

In medial canthal reconstruction, continuity of skin texture, thickness and colour are important. If deeper structures are involved such as the nasal sidewall, medial canthal tendon or lacrimal apparatus, careful reconstructive planning is required.

Clinical appearanceClassic rolled edges and prominent vessels usually point to a BCC (basal-cell carcinoma). Chronic scaling with redness and ulceration tend to be associated more with squamous cell carcinoma. Melanomas tend to have dark pigmentation with satellite lesions.

Principles of reconstruction• Match tissue used for flaps or grafts as

much as possible• Use a vascularised graft together

with a flap if two lamellae need to be reconstructed

• Provide adequate canthal fixation• Minimise vertical traction on the lids• Perform appropriate direct closure

before sizing the wound for a flap or graft

• Balance the complexity of the procedure with improvement in outcome

Tumours involving the medial canthal region and/or lacrimal system require complex reconstructive planning.The literature is replete with various types of skin-muscle flaps to repair medial canthal defects. However, many of these fail to address the issues of eyelid function and stability or recreation of lacrimal drainage.

Complete removal of the lesion is important as spread posteriorly may result into extension into the brain.

Full-thickness skin grafts can be used to close defects, but should be thinned to match the surrounding tissue.

Partial interruptions of the canaliculus can be repaired primarily with silicon intubation and surgical re-anastomosis of the ends.

Crawford stents (Jedmed) for bicanalicular and Mini Monoka (FCI) for mono-canalicular repair are good options. The stents are usually left in situ for 3 months and then removed.

If the lacrimal system is damaged, a conjunctivodacryocystorhinostomy may be required with a Jones tube.

Surgical examples1. Patient A is a 67 year old with an

ulcerating lesion in his right medial canthus. This has been present for 6 months and he complains that his spectacles irritate this area. Careful examination revealed a dumb-bell shaped tumour.

ManagementThe tumour was marked with a surgical pen. A surgical margin of 4-5 mm margin was used.

The tumour was excised to the level of the periosteum and a frozen section was performed (Fig 1). A second excision was performed due to the tumour extending close to the nasal margin. A modified glabellar flap was created and thinned (Fig 2). The defect was closed and a small dog-ear excised (Fig 3).

Sutures were removed at 14 days with a good cosmetic result (Fig 4). Histology confirmed a basal cell carcinoma.

2. Patient B had a lesion in his left medial canthal area (Fig 6).

This was treated with cryotherapy, but grew back within four months. Surgical margins were also checked with frozen section and a small glabellar flap was created to fill the defect (Fig 7).

This lesion was also a basal-cell carcinoma.

Despite thinning of the flap, the final result showed a thickness imbalance which will require massage over the next few months (Fig 8).

Diagnosis and Management of Medial Canthal Tumours

Dr Brian van OnselenOphthalmologist, Sandhurst Eye Centre

Sandhurst, Johannesburg

Basal cell carcinoma Melanoma Squamos Carcinoma

Ophthalmi pinion 10 Vol 1 No 1 2018

DiscussionMedial canthal tumours are often not noticed by patients or are ascribed to irritation of the skin.

Surgical removal often leaves large defects to fill. Options for treating these defects range from allowing natural granulation to free skin grafts and/or flaps.

A good cosmetic result is possible with good planning and judicious application of surgical principles.

In 1993, Spinelli divided the peri-ocular region into five zones, and recommended selection of a reconstruction method considering each regional feature. In the medial canthal area, a local flap or upper eyelid myocutaneous flap are good choices.

The forehead and glabellar flap are thick, and if transferred without thinning can

cause a trap-door phenomenon or pancake-like bulging.

Lykoudis reported the combined use of a glabellar flap together with a nasolabial flap to repair large defects. This was called a“pickaxe” double flap technique because the shape is similar to that tool.

When the defect involves full-thickness medial eyelid or sacrifice of the medial canthal tendon, the remaining eyelid must be reapproximated and fixated to the periosteum.

If only the anterior limb of the medial canthal tendon is lost, it may not cause destabilisation of the canthus if the posterior limb is intact. A suture can be used to attach the tendon to either the stump of the tendon or directly to the periosteum. Failing this, a titanium miniplate can be fixated to the bone and the tendon sutured to the plate.

Full-thickness eyelid defects involving more than 50% of the lid can rarely be closed and reapproximated to the canthal tendon primarily. In these instances both anterior and posterior lamellar components must be addressed via lid-sharing techniques, free grafts and flaps.

References3. Collin, 2006 J R O Collin A. Manual of

Systematic Eyelid Surgery4. Nerad, 2001 JA Nerad. Oculoplastic Sur-

gery5. Czyz et al, Reconstructive options for

the medial canthus and eyelids follow-ing tumour excision. Saudi Journal of Ophthalmology Jan-Mar 2011

6. Ogino et al, Medial canthal reconstruc-tion with multiple local flaps. JPRAS March 2018

Fig 1 Fig 2 Fig 3

Fig 4 Fig 5 Fig 6

Fig 7 Fig 8 Fig 9

Ophthalmi pinion11Vol 1 No 1 2018

Lamellar Corneal Surgery: A journey

Dr Malcolm Carey, Ophthalmologist and Corneal Surgeon, Umhlanga Eye Institute

Prior to DMEK, the graft was cut leaving a residual thickness of 100 -200µm in a pro-cedure called DSAEK (Descemets Stripping

Automated Endothelial Keratoplasty). It is important to mention this procedure de-spite the risk of an “alphabet soup of ac-ronyms” as DMEK has certain safety and outcome advantages over DSAEK.

A recent literature review by the Ameri-can Academy of Ophthalmology3 showed DMEK patients see better due to less in-terface haze with up to 85% of eyes see-ing 20/25 (or better) at 6 months. Mean induced astigmatism was +0.33 diopters- similar to DSAEK but much lower than PK. Hyperopic spherical shift was average +0.43 diopters- much less than DSAEK, which in-duces up to 3 diopters of hyperopia.

here have been tremendous advances in lamellar corneal surgery over the past few years and this has led to major gains in clinical outcomes.

The learning curve of these procedures is steep This refers mainly to DMEK (Descem-ets Membrane Endothelial Keratoplasty), which is a variation of enthothelial kera-toplasty and DALK (Deep Anterior Lamel-lar Keratoplasty), which retains patients healthy endothelium but replaces abnor-mal stromal tissue.

The benefits, however, are numerous and intuitive and worth pursuing.

Endothelial pathology has always left ophthalmologists with heavy hearts as it traditionally required a full thickness transplant or PK (penetrating keratoplas-ty). This left many patients with, for ex-ample, Fuchs Endothelial Dystrophy and progressive cataracts losing vision with surgeons hesitant to make things possi-bly worse with intervention as the cornea may decompensate.

The first DMEK case was published in 2006 by Gerrit Melles of Rotterdam.2 This involves the insertion of Descemets membrane and endothelial layer (6-15µm thickness) which is pre-stripped from donor cornea and in-serted and unscrolled in a host eye which has undergone descemetorrhexis (careful removal via peeling with forceps) of dis-eased endothelium. The donor membrane is held in place with gas bubble tamponade and patient posturing.

Figure 1. Layers of cornea highlighting lev-els of different approaches. Photo Credits1

Figure 2 Decompensated cornea (Pseu-dophakic Bullous Keratopathy)

Figure 3: Day 1 and 7 post DMEK. Note inferior Peripheral Iridectomy to prevent pupil block)

Figure 4: OCT scan of cornea showing cross section pre and postop with significant improvement in corneal thickness

Ophthalmi pinion 12 Vol 1 No 1 2018

Immune rejection rates were 1.9% vs 10% in DSAEK. The most common complication after DMEK was partial graft detachment requiring gas rebubbling (28.8%), followed by raised intraocular pressure (up to 22%).

It is clear that DMEK has a lot to offer- so what are the barriers to entry? The tissue needs to be prepared and there are various techniques described, but all run a real risk of the endothelial graft tearing, which ren-ders tissue unsuitable.

This is a difficult situation as a cornea may cost a few thousand US Dollars. Some of the international eyebanks offer a prestripping service which is useful but adds significantly to the cost of the procedure. Once the graft is prepared, it is stained with vision blue to allow visualisation and then inserted into the eye through special glass injector.

The orientation of the graft is important as an upside down graft “falls off” as soon as gas tamponade is resorbed.

There are several technical strategies to determine graft orientation. An example is using a S-stamp which is stamped onto the DM side of graft. Correct orientation of the S elegantly shows correct orientation.

The unscrolling of a DMEK graft involves support from surrounding structures name-ly the iris below and corneal stroma above. Fluid waves are used to unroll the graft. A very tight scroll may be difficult to unravel and this is why donors under age 50 are sel-dom used. This can be very tricky and one has to be patient and careful.

DMEK is complicated by eyes with abnormal anterior chambers, for example, presence of a glaucoma valve or anterior chamber lens. This disrupts fluid waves and can catch the edge of the graft damaging endothelium and limiting unscrolling. It is also possible to perform DMEK in an eye with previous penetrating keratoplasty but the risk of postoperative detachment is higher if the graft is not perfectly centred within the old graft.

Figure 5. Schematic of DMEK graft in Anterior Chamber. Usually scrolls with endothelium on outer surface. Credit Dr Mike Straiko MD: Devers Eye Institute

Figure 6. Correct orientation of S elegantly shows graft orientation. (Day ! and Day 3)

Once the graft is in position, a gas tamponade is placed behind the graft and patient postures to keep the graft in position.

A certain percentage may need rebubbling if graft detachment occurs (usually 30% or more require rebubbling).

Cystoid macular oedema occurs in 12.5% of DMEK cases but reduces to 0% if intensive topical steroids are used for the first week.4

Another study reported 0% rejection over the first year if low dose topical cortisone was continued vs 6 % if discontinued.5

Besides the cost of tissue, the equipment costs for DMEK are comparatively low. Very little high tech specialised equipment is re-quired which makes it attractive in emerg-ing countries. Despite the steep learning curve and the cost and scarcity of suitable donor tissue, DMEK is a major advance in corneal surgery and outcomes improve rap-idly with experience.6

Figure 7: DMEK in an eye with Artisan Iris Claw lens. The tissue was injected carefully orientated to minimise manipulation

Figure 8: DMEK in failed previous penetrating graft. This reduces morbidity especially in a graft with good regularity.

Figure 9: Two OCT scans of corneas showing detachment. The second required rebubbling

Ophthalmi pinion13Vol 1 No 1 2018

Figure 10: Corneal scar with OCT scan showing extent of opacity

Figure 12: Excellent recovery after 1 week with good apposition of corneal layers

Figure 11: Day 1 post DALK. Note good clarity and presence of air bubble to tamponade superior macroperforation. OCT below shows rolled edges of perforation with gas interface visible

Ophthalmi pinion 14 Vol 1 No 1 2018

Deep Anterior Lamellar Keratoplasty(Please see figures 11 and 12 on page 13)We will now focus on DALK which, as per the introduction, replaces the patients ab-normal stroma with health donor stromal graft and is most commonly performed on patients with keratoconus and corneal scarring from trauma and infections. The patient retains their own endothelium and endothelial rejection cannot occur.

This is a tremendous benefit especially in younger patients who may require multiple transplants in their lifetime due to failed penetrating keratoplasty. The reported re-jection rate for PK varies and is significant in high-risk corneas and can exceed 35% at 3 years.7 Comparison studies with lamellar surgery show rejection rates of 17%8 in PK.

DALK is technical surgery but worth the at-tempt as the surgery can be converted at any stage to PK.

The procedure involves the separation of endothelium and Descemets membrane from stroma using manual dissection or preferably air injection via the “Big Bubble Technique” described by Anwar.9 This clean-ly separates the layers and reduces risk of interface haze postoperatively.

Advantages of this technique include early steroid tapering, decreased risk of second-

ary glaucoma and increased early tensile strength of graft.

There is no benefit in post operative astigma-tism or visual acuity.10 Indeed, penetrating keratoplasty patients may have better early vision due to early interface haze and wrin-kling of the endothelial layer which may occur due to poor fit with the new flatter stroma in DALK patients. This improves over time.

With DALK there is a risk at any stage of per-foration and if major, conversion to PK may be necessary. A microperforation or even larger defect can often be managed and DALK successfully completed. The surgery is technical but rewarding. The following case study illustrates potential issues. A young patient with corneal scarring following se-vere diffuse lamellar keratitis after LASIK many years ago has poor vision and loss of confidence in further surgery. She found the concept of lamellar surgery attractive.

Intraoperatively, there was a tear superiorly due to peripheral attachment during stro-mal removal despite good big bubble. There was no extension and a decision was made to continue. Air was injected to tamponade the defect at end of procedure.

The patient has recovered well so far but still has a long road ahead in terms of astig-matic management and correction with contact lenses and suture removal.

The field of corneal surgery is evolving rap-idly and it is tremendously exciting for any-one on that journey. The pioneers of these techniques are acknowledged for their in-credible work, which continues to improve the outcomes for our patients.

References1. http://www.avidscience.com/wp-content/up-

loads/2017/08/descemet-membrane-endothe-lial-keratoplasty-review-of-the-literature-and-de-scription-of-a-new-no-touch-technique.pdf

2. Melles GR, Ong TS, Ververs B, van der Wees J. Descemet membrane endothelial keratoplasty (DMEK). Cornea. 2006; 25:987-990.

3. Sophie X. Deng, MD,1 W. Barry Lee, MD, Oph-thalmology 2017;- :1e 16 ª 2017 by the Ameri-can Academy of Ophthalmology

4. Hoerster R, Stanzel TP, Bachmann BO, et al. In-tensified topical steroids as prophylaxis for mac-ular edema after posterior lamellar keratoplasty combined with cataract surgery. Am J Ophthal-mol. 2016;163:174-179.

5. Price MO, Scanameo A, Feng MT, Price Jr FW. Descemet’s membrane endothelial keratoplas-ty: risk of immunologicr rejection episodes after discontinuing topical corticosteroids.Ophthal-mology. 2016;123:1232-1236.

6. Dapena I, Ham L, Droutsas K, van Dijk, K Mout- souris GR, et al. Learning curve in Descemet’s Membrane Endothelial Keratoplasty. Ophthal-mology. 2011; 118: 2147-2154.

7. Bartels MC, Doxiadis II, Colen TP, Beekhuis WH. Long-term outcome in high-risk corneal transplantation and the influence of HLA-A and HLA-B matching. Cornea. 2003;22(6):552-6

8. Anshu A, Price MO, Price Jr FW. Risk of corneal transplant rejection significantly reduced with Descemet’s membrane endothelial keratoplas-ty. Ophthalmology. 2012;119:536-540.

9. Anwar M, Teichmann KD. Deep lamellar kerato-plasty: Surgical techniques for anterior lamellar keratoplasty with and without baring of de-scemet’s membrane. Cornea. 2002;21:374–83

10. Comparison of outcomes and complications of deep anterior lamellar keratoplasty and pene-trating keratoplasty performed in a large group of patients with keratoconus. Khattak A, Nakhli FR, Al-Arfaj KM, Cheema AA. Int Ophthalmol. 2018 Jun;38(3):985-992

The field of corneal surgery is evolving rapidly and it is tremendously exciting for anyone on that journey. The pioneers of these techniques are ac-knowledged for their incredible work, which con-tinues to improve the outcomes for our patients.

Ophthalmi pinion15Vol 1 No 1 2018

th National Congress of theOphthalmological Society of South Africa

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