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TRAUMATIC ECTOPIA LENTIS Most common cause of ectopia lentis. Lens trauma is also associated with retinal dialysis or tears, as the posterior capsule is attached to the anterior hyaloid face via Weigert’s ligament, and thus may transmit the traumatic forces to the vitreous base.

Inflammatory and Immune Disease

ATOPIC DERMATITIS, ATOPIC CATARACTS Skin and lens share a common embryologic origin. Cataract is seen in 25% of patients with atopic dermatitis; patients are usually 20 to 30 years old with bilateral anterior subcapsular shieldlike plaques that tend to do poorly at surgery. Cataract also seen in ectodermal dysplasia (Rothmund’s and Werner’s syndromes) and acrodermatitis enteropathica.

PHACOANTIGENIC UVEITIS, PHACOANAPHYLAXIS Lens proteins leak through ruptured capsule, causing zonal granulomatous inflammation (histopathologic ‘‘zones’’ of inflammatory cells: PMN infiltrate first around the lens material, followed by epithelioid histiocytes, then finally a mononuclear infiltrate). Almost always seen following trauma or surgery (thus, a 3–7% coincidence with sympathetic ophthalmia). Treat by cataract extraction and anti-inflammatory medication.

UVEITIC CATARACT Usually PSC, seen with any chronic uveitis but especially with JRA (especially pauciarticular, RF negative, ANA positive) and Fuchs’ heterochromic iridocyclitis (70% have cortical cataract, with favorable prognosis after CE).

Cataract Surgery

PREOPERATIVE

Determine visual disability: note functional complaints, record loss of BCVA, and do a complete eye exam. Particularly note physical exam factors that may complicate surgery or recovery, such as deep brow, presence of conjunctival filtering bleb, corneal guttae, shallow AC, poor dilation, presence of pseudoexfoliation or phacodonesis, and fundus pathology that needs treatment or that may limit visual recovery.

Phacoemulsification after vitrectomy: may have zonular instability and little posterior support, with a ‘‘floppy’’ posterior capsule. If there is a need to convert to extracapsular cataract extraction (ECCE), expression is often difficult, and lens must be lifted out.

Diabetic retinopathy: potential massive progressive of DR after surgery, especially with vitreous loss and increased risk of CME.

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Complete medical history: especially inquire about the use of anticoagulants (Coumadin, aspirin, Plavix, Ticlid, etc.) and anesthesia risks (coronary artery disease, emphysema, etc.).

Determine surgical plan: A-scan, keratometry, presence of astigmatism, and refractive goal. Typically have an IOL available for the ‘‘bag,’’ sulcus (0.5 D less power), and AC. Obtain and document informed consent.

PREPROCEDURE CHECKLIST On the day of surgery, at least mentally review these issues for each patient (mnemonic: ABC-ATLS-ABC).

Accurate patient and eye

Big pupil

Check consent and preop note

A-scan review

Table (set up the bed, wrist rest, etc.)

Lenses (ensure IOLs of proper power are available)

Scope (ensure working order, and zero the X, Y, Z axes) and supplies (ensure nursing has the instruments that you need)

Anesthesia (retrobulbar, topical, etc.)

Ballottement of the globe if retrobulbar anesthesia used

Cleanse patient and surgeon (scrub)

EXTRACAPSULAR CATARACT EXTRACTION (ECCE) TECHNIQUE Many variations on surgical technique; goal is to get the cataract out as efficiently as possible with as few complications as possible.

Administer retrobulbar anesthesia: may also use topical, sub-Tenon’s, parabulbar, etc.

Technique: use 1:1 mixture of 2% lidocaine without epinephrine and 0.75% bupivacaine (and may use Wydase), 1.25 inch, 22 gauge needle. Ensure that the patient and surgeon are in a comfortable position. Have the patient’s eyes in primary gaze, place finger on the inferior orbital rim about at the junction of the medial two-thirds of the eyelid and lateral one-third (approximately at the temporal limbus). Begin lateral to finger, and advance needle horizontally through the eyelid half the needle length with bevel up (may also pull down the lid and enter through the conjunctival fornix). Once past the globe equator, aim for the contralateral occiput, entering approximately 1 inch total length (never exceed 31 mm and never cross the midsagittal plane). Inject 4–5 cc, remove the needle, then apply external compression to the eye for several minutes of 20 seconds pressure and 10 seconds release. Beware of patients with deep-set eyes or long axial length.

Complications: retrobulbar hemorrhage (1–3%) with rapid orbital swelling, proptosis, globe immobility, elevated IOP, inability to separate the eyelids, massive ecchymosis of the lids and conjunctiva,

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214 LENS

and decreased VA (optic neuropathy or CRAO); treat with lateral canthotomy/cantholysis, digital pressure to create orbital pulsations, and osmotic diuresis. Also common are globe perforation (1:1000) or direct CNS spread (1:350–1:500), seen as confusion, extraocular paresis or amaurosis in the contralateral eye, shivering, convulsions, nausea, vomiting, and significant changes in vital signs.

Administer lid or facial nerve block, such as a modified van Lint injection at the lateral canthus.

Adjust wrist rest, tape head, prep and drape patient, and place lid speculum.

The most important part of the preparation is use of povidoneiodine (Betadine) and a drop placed in the conjunctiva fornix (if patient is allergic to Betadine, use baby shampoo scrub and topical antibiotics).

The most important part of the draping is to drape the lashes out of the surgical field.

Consider bridle suture if there is poor superior limbus exposure or deep socket: hold the SR with large forceps, and pass 5.0 silk on a blunt (e.g., BV) needle underneath the muscle, then attach suture to drape.

Measure white to white with calipers.

Do peritomy, using 0.12 forceps and blunt Westcott scissors.

Use wet-field cautery to obtain scleral hemostasis.

Groove perpendicularly with crescent blade, 1–2 mm posterior to the limbus, 11 mm chord length, one-half scleral thickness.

Tunnel in a lamellar plane with crescent blade toward the limbus; keep blade flat against the globe, and advance until the blade tip is seen in the limbal vessels.

Do paracentesis.

Instill viscoelastic into AC.

Enter AC with microkeratome through the central wound; keep level with iris plane to create triplanar wound.

Perform capsulotomy with cystotome, can-opener versus capsulorrhexis.

Hydrodissect and may hydrodelineate the lens with BSS.

Rock the nucleus: push down toward 3 o’clock, then 9, 6, and finally 12 o’clock.

Extend the wound with cresent blade or corneoscleral scissors to the left and right.

Preplace safety sutures, using 10.0 nylon, at 10 and 2 o’clock.

Express nucleus using lens loop superior to push down wound edge and use gentle pressure with muscle hook inferiorly at limbus.

Tie the two safety sutures.

Perform irrigation and aspiration with manual Simcoe cannula, engage cortex peripherally, pull to center, and aspirate.

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Place viscoelastic into bag.

Place IOL, use McPherson’s forceps to grasp lens oriented as a backwards ‘‘S.’’ Place inferior haptic first, and use Sinskey-type hook to spin lens into bag.

Apply Miochol to constrict pupil.

Suture wound with 10.0 nylon; ensure watertight closure.

Remove bridle suture; close conjuctiva with cautery or 8.0 Vicryl, and inject subconjunctival Decadron 8 mg and Ancef.

Remove speculum and drapes, clean off Betadine, then place Maxitrol ointment, two eye pads, and Fox shield. Instruct patient not to bend, lift, strain, or cough.

At 1 day postop, remove patch, begin steroid and antibiotic drops, and advise patient regarding activity restriction and shield or glasses over eye at all times.

INTRAOPERATIVE COMPLICATIONS

Suprachoroidal hemorrhage: risk factors include chronic glaucoma, hypotony, older age, hypertension, and atherosclerosis. See loss of red reflex, experience posterior pressure, with risk of loss of intraocular contents. Immediately place finger over wound, and quickly suture wound closed, then consider sclerostomies.

Vitreous loss: signs include sudden iris or lens bounce, change in pupil size or peaked pupil, decreased AC depth, decreased phacoemulsification power or inefficient aspiration, and posterior loss of lens particles. Stop phacoemulsification, but do not immediately remove phacoemulsification instruments; maintain AC with viscoelastic. If there is adequate compartmentalization with no mixture of vitreous and lens and rent is small, can continue slow phacoemulsification with low flow. However, phacoemulsification will not cut vitreous and increases risk of RD if vitreous is aspirated by phacoemulsification.

Risk of vitreous loss: zonular weakness (PXS, trauma, Marfan syndrome, etc.), small pupil, and previous vitrectomy.

Anterior vitrectomy: avoid hydration and traction of vitreous. Remove vitreous down to posterior capsule plane; may perform core vitrectomy. Consider pars plana vitrectomy, which offers greater vitreous cleanup: small peritomy; using 20 gauge microvitreoretinal (MVR) blade, enter at 3–4 mm posterior to limbus, then vitrectomy through pars plana with separate irrigation through paracentesis.

POSTOPERATIVE COMPLICATIONS

Astigmatism: most likely caused by a tight suture following ECCE; may cut suture at steep axis after 6 weeks if >3 D of astigmatism.

Corneal edema: usually temporary, but may be irreversible if there is significant endothelial cell loss (preexisting guttae or other corneal pathology or excessive phacoemulsification time). Also, historically,

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216 LENS

Brown-McLean syndrome with peripheral corneal edema from flat AC may be seen following ICCE.

Capsular block syndrome: typically occurs 1 to 2 weeks postop, with a clear space seen between the IOL and posterior capsule without capsular fibrosis that represents retained viscoelastic. May be treated with YAG laser capsulotomy. Also seen months or years later, with milky substance posterior to IOL and myopic shift, from hydration of retained cortex with fibrosis of anterior capsule to IOL; prevent fluid egress from the bag.

Capsular centration syndrome, capsular phimosis: anterior capsule contraction with decreasing capsulorrhexis size that may cause IOL decentration.

Cystoid macular edema: 50% incidence by FA after ICCE, 20% after ECCE, and much less after routine, uncomplicated, fast phacoemulsification. Usually occurs at 4 to 14 weeks postop. Risk factors include age, vitreous loss, AC IOL, diabetes, and microscope light toxicity. Edema mostly caused by inflammatory release of prostaglandins created from arachidonic acid derived from cell membranes. Treat with a topical NSAID and/or steroid (e.g., Volaren and PF 1% qid). Ninety percent of patients with a PC IOL recover >VA 20/40.

Delirium: may be from anticholinergic toxicity, sensory deprivation, RD, fall, or stroke.

Diabetic retinopathy progression: most important predictor of good postop VA in diabetic patients is the absence of preop DR. Ninety percent of nondiabetic patients are 20/40 or better after surgery versus only 60 to 70% of diabetic patients; one third of NPDR will progress in the operative eye postop.

Epithelial or fibrous downgrowth: may cause segmental corneal edema after penetrating injury (trauma or surgery).

Glaucoma: after CE, one third of patients have a mildly increased IOP, one third remain normal, and one third have a lower IOP. Glaucoma may develop from a very high early IOP spike, usually from retained viscoelastic or inflammation, or from long-term elevated IOP, usually from TM damage or steroid induced.

IOL decentered or wrong power: explant by tilting IOL vertically, then cut horizontally with intraocular scissors, and pull out in two pieces. Best time to explant is within 7 days before significant fibrosis occurs.

Posterior capsule opacification: incidence depends on IOL type, although usually <10%; needs YAG laser capsulotomy.

PEDIATRIC CATARACT EXTRACTION Consider surgery if opacity is >2 mm and in visual axis; a posterior opacity is more amblyogenic. Earlier surgery is better; operate for congenital cataract within 6 weeks of life. Critical period of visual development is in first few months; thus, bilateral visually significant cataracts can cause irreversible amblyopia and sensory

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nystagmus. Surgery for bilateral cataracts before age 2 months has better visual prognosis (80% of patients are 20/50 or better). Mean VA for congenital unilateral cataracts operated on within 2 months of age is 20/ 60; after 20 months, is 20/160.

Surgery is usually lensectomy (often can just aspirate lens), primary capsulotomy, and anterior vitrectomy if patient is <5 years old. Expect strong Weigert’s ligament; thus, avoid ICCE. Typically leave aphakic if patient is <2 years old; if older, place one piece PMMA or acrylic lens in the bag.

Extended wear CL preferred over aphakic spectacles to reduce aniseikonia and astigmatism. Historically epikeratophakia was attempted. Remember that lifelong loss of accommodation is typical after CE; thus, prescribe bifocals.

Pediatric postoperative complications: posterior capsule opacification (PCO) in 100% of patients, amblyopia, second membrane formation from proliferation of retained lens cells, glaucoma (5–30%), RD (5%), postoperative inflammation, CME rarely, and corneal decompensation, especially with Peters’ anomaly.

PHACOEMULSIFICATION TECHNIQUE An ECCE technique that allows removal of the lens through a smaller incision—often without sutures and with topical anesthesia—with a lower complication rate. The phacoemulsification unit utilizes ultrasound energy to emulsify the lens nucleus in the eye. Diaphragm machines have slow but exponential rise in vacuum. Peristaltic machines use rollers to ‘‘milk’’ the fluid through the tubing and have a rapid stepwise rise in vacuum (e.g., Alcon Legacy). Venturi systems use gas flowing across a port to build a vacuum and show a rapid linear rise in pressure; also, the aspiration tip does not need to be occluded to build pressure (e.g., Storz Millennium).

VISCOELASTICS Complex molecules used to maintain intraocular spaces, provide protective coating, and assist surgical maneuvering.

Cohesive (e.g., Healon, Provisc, Amvisc): sodium hyaluronidase, high molecular weight; adhere to themselves and are easy to remove.

Dispersive (e.g., Viscoat, Ocucoat): low molecular weight; provide better coating of the endothelium.

YAG LASER CAPSULOTOMY Uses the photodisruptive power of the YAG laser to open the posterior capsule. Wait at least 6 weeks after CE; platetype IOLs may decenter even years later. Treat with an alpha-agonist preprocedure, then defocus the laser posteriorly and apply the laser energy usually in a cruciate or circular pattern at 0.5–2.0 mJ. Has a 1% risk of RD; thus, perform DFE at 4 weeks.

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