Femtosecond Laser-Assisted Cataract Surgery – Teaching Tutorial

HOW TO ADAPT SURGICAL TECHNIQUETips from Prof. Chee Soon Phaik, MD, SNEC, Singapore

Introduction from Prof. Boris MalyuginAbout Prof. Chee

Prof. Chee is a world-renowned expert in cataract surgery that needs no introduction. Establishing herself as a superb clinician, researcher and teacher, she is having unique experience in dealing with wide spectrum of complicated cataract cases.

This booklet is very special as it clearly demonstrates on how the vast clinical expertise may be perfectly paired and even further enhanced with the latest and up-to-date femtosecond laser technology. I believe this unique amalgamation being in the core of the cataract surgery reach-ing the new heights in a foreseeable future.

Boris Malyugin MD, PhD

Professor of OphthalmologyDeputy Director General (R&D, Edu)S. Fyodorov Eye Microsurgery Clinics

President, Russian Ophthalmology Society ESCRS Board MemberAcademia Ophthalmologica Internationalis, MemberInternational Intraocular Implant Club, Member

FEMTO LDV Z8 owner and regular user

Docking InstructionsThe FEMTO LDV Z8 has a liquid interface for cataract surgery. It contains a two step docking process: first, place the suction ring on the center of the eye. Second, dock the handpiece to the suction ring. A «click» sound ensures proper docking.

Miyoshi speculum (ASICO) – specially created for Ziemer laser systems(www.asico.com/products/speculum/miyoshi-z-lasik-speculum)

1

2

nasally positioned

3

Step-by-step processing

Always use an open wire lid speculum (e.g. Miyoshi) 1

Place the interface on the eye (Suction ring clip is nasally positioned) 2

When centered on eye, begin suction Do a vacuum test 3

Fill with BSS up to the rim (3– 5 ml) 2 3

Click!

4

5

6

6

Dock the handpiece to the suction ring Pivoting action of handle to engage pin (latch must click) 4

Check the top view image and ensure good centration / no bubbles 5

Hold the handpiece gently, do not grip tightly 6

Accurate preparationTo get the best results, you and your team need to prepare the femto surgery and plan in advance. This helps in getting a smooth start.

Patient Selection for starters

I do not suggest starting with the most complex cases. Select patients with:

Eyes that are normal, except for the cataract Wide palpebral aperture, lax lids that

are not puffy Pupils that dilate well, minimum of 6 mm Cataract of moderate density Cooperative patient

Starters should avoid

Uncooperative patient Small pupil Tight small palpebral aperture Dense corneal opacities Advanced glaucoma Large pterygium Very shallow anterior chamber

The Day of SurgeryNow that you have selected the first patients to work with and prepared everything with your team (mydriatic drops, laser training etc.) you will have a smooth and successful surgery day. Remember: there is a learning curve with everything – including the femtosecond laser.

Prepare for a perfect capsulotomy

Increase power settings on the FEMTO LDV Z8 if you see: corneal opacities, anterior subcapsular fibrosis

Good pupil dilation: minimum of 0.8 mm larger than intended capsulotomy Use mydriatic drops Use topical NSAID starting 1 day prior to surgery and just after

femtosecond laser treatment Choose to center on pupil or limbus Capture eye in the center of the suction ring is very important Double check your settings to ensure a good outcome

Capsulotomy

Laser power can be adjusted The vertical cutting height of the capsulotomy spiral

is automatically positioned on the anterior capsule

In the ORThe laser has an automated edge detection and suggests the treatment area. You can always customize the trajectories to your desire or to your patient's needs.

My tips

Suggested diameter 5.0 mm Stain with capsule dye if necessary

(e.g. white cataract) Inject OVD and remove capsule disc or move

edges / dimple down to ensure capsulotomy is complete

Visually inspect for tags and bridges Tags – pulled radially inwards Bridges – complete with capsulotomy

maneuvers

Fragmentation

Currently 4, 6, 8 and 16 segments Auto-recognition of anterior and posterior

capsules and placement of the fragmentation pattern between safety margins

Select fragmentation pattern and incision size depending on the nuclear sclerosis grade

Fragmentation pattern can be placed independent of capsulotomy position

Laser power can be adjusted according to the cataract grade

Clear Corneal Incisons (CCI)

Capable of 1 main and 2 paracenteses/side ports Angles can be chosen freely Location of the bend point between the segments can

be chosen from 20 % to 80 % of the cornea thickness Place as peripheral as possible, avoid arcus

and conjunctiva

Incisions PlanningIt is possible to program any angle with the laser. I suggest to take your manual incisions profile as a template (use post surgery OCT). This helps in planning the placement and architecture of the incisions.

My tips

Study your typical incision positions Take your manual incision profile as a

template (post-op OCT) My suggestion for incision size:

– Main incision: + 0.15 mm (wider than your manual incision)

– Side port incision: 0.9 mm My geometry: 2 planes for main incision,

1 plane for side port

40º to horizontal iris plane–55º

Hydrodissection

Excessive hydrodissection may lead to intraoperative cap-sular block – sealed cortex/anterior capsule prevents fluid egress into anterior chamber

Careful hydrodissection can help avoid: Anterior Capsular Rupture (ACR) Dropped nucleus Therefore: Examine for gas bubbles and release gas Reduce volume of BSS and injected speed Be gentle

IntraoperativeHere are some tips on how I work after the laser treatment:

Phaco technique

Advocate lateral separation without the sculpting Impale and separate near the equator

and posterior capsule Phaco parameters:

– Minimize ultrasound energy – Increase vacuum

Use instruments if necessary (chopper/prechopper)

Posterior polar cataract: adjust fragmentation depth to stop above the posterior polar cataract. Do not hydrodissect but instead dissect with viscoelastic.

Differences when using the laser

Capsulotomy cuts slightly into cortex – hydrodisection occures differently

Absence of cortical frill – different to aspirate Need to be on look out for tags, dog ears,

tongues of capsule which may progress to ACR – difficult to see

Aspirate beyond the capsulotomy rim Bimanual Irrigation / Aspiration (IA)

to avoid stressing subincisional site

Different Surgical Technique Here is an overview of what you need to be aware of when working with a femtosecond laser in cataract surgery.

Cases where the laser is of special advantage

Low endothelial cell count Dense cataract White cataract Subluxated cataract PEX Syndrome Posterior polar cataract Traumatic cataract

Pulse spacing – conventional laser systems No space – overlapping spots, Ziemer LDV Systems

Low Energy Femtosecond Laser TechnologyThe Ziemer laser systems work without spacing between the laser spots. In fact, they are overlapping which gives a smooth and thorough cut. This is possible due to the low energy and high repetition rate that is used.

Fragmentation pattern with the FEMTO LDV Z8 (Courtesy of Prof. Theo Seiler, Zurich, Switzerland)

Singapore National Eye CentreOcular Inflammation and Immunology DepartmentHead and Senior ConsultantFRCOphth, FRCS(G), FRCS(Ed), MMed(S’pore)

Prof. Chee Soon Phaik

Soon-Phaik Chee, MD, is a Professor at the National University of Singa-pore and Duke-National University of Singapore Graduate Medical School, Singapore. She is a Senior Consultant and heads both the Cata-ract Subspecialty Service and Ocular Inflammation and Immunology Ser-vice at the Singapore National Eye Centre (SNEC). In addition to her clinical commitments, Dr Chee is concurrently the Direc-tor of Fellowships and a member of the EXCO Committee in SNEC. She also serves as group lead member of the Cataract research team at the Singapore Eye Research Institute. She obtained her Master of Medicine (Ophthalmology) at the National University of Singapore and was admit-ted as a Fellow of the Royal College of Surgeons of Glasgow and Edin-burgh and the College of Ophthalmologists, UK. She subsequently com-pleted her fellowship in Uveitis and Oculoplastics, Lacrimal and Orbital Surgery at Moorfield’s Eye Hospital, London in 1993.Dr Chee’s research interests in cataract include the management of com-plicated cataracts such as the dense posterior polar cataract, subluxated

cataracts, premium intraocular lens implants and femtosecond laser assisted cataract surgery. In addition to innovations in surgical tech-niques, she has also designed intraocular instruments which greatly aug-ment surgeons’ abilities to overcome difficulties and improve the out-comes in these highly demanding cases. In the field of uveitis, she has been the President of the Asia-Pacific Intra-ocular Inflammation Study Group (APIISG) since 2013. She is also a mem-ber of the International Uveitis Study Group, Clinical Consensus Group (Standardisation of Uveitis Nomenclature) and an International Council member of the IOIS International Council. She has published extensively on Cytomegalovirus infection of the anterior segment, Ocular Tuberculo-sis, Dengue Maculopathy and Vogt-Koyanagi Harada disease.She has authored over 200 peer reviewed scientific papers and book chapters and is a member of several editorial boards including Ocular Inflammation and Immunology, Journal of Ophthalmic Inflammation and Infection and Journal of Cataract and Refractive Surgery.

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