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Up Front | Sep 2008

Topical, Subconjunctival Anesthesia for Transclerally Fixated IOLs

Scleral fixation of secondary IOL implantation in aphakic vitrectomized eyes.

Various methods of aphakic correction may be used in vitrectomized eyes; however, the choice of procedure will depend on the patient's visual potential, extent of posterior segment pathology, age, and fixation and integrity of the lens capsule and zonular support.1 Another—arguably better—option is a scleral or anterior chamber IOL, which facilitates faster rehabilitation compared with aphakic glasses or contact lenses.

No consensus currently exists on the optimal method for IOL implantation in eyes without capsular support. Some surgeons prefer to implant a scleral-fixation IOL in the absence of posterior capsular support, and others prefer to use an anterior chamber IOL.2-5 Many ophthalmologists have adopted the use of scleral-fixation IOLs on the assumption that its placement in the posterior segment results in sufficiently less corneal endothelial damage, glaucoma, and cystoid macular edema (CME).6,7 Compared with the anterior chamber IOL, a scleral-fixation IOL also minimizes aniseikonia in contralateral eyes that are phakic or pseudophakic.6,7

Scleral fixation of a PMMA IOL is an effective technique; however, it is technically more difficult, involves more operative time, and requires an incision as large as 7 mm. Therefore risks, such as intraoperative hypotony, vitreous or choroidal hemorrhage, and postoperative astigmatism, jeopardize visual outcomes. In small-incision cataract surgery with foldable IOLs, the incidence of complications has significantly decreased.8,9 Topical anesthesia for IOL implantation has become increasingly popular because it may avoid regional block, provides excellent patient comfort and satisfaction without injecting an anesthetic agents, ensures immediate postoperative visual and physical recovery, and minimizes postoperative ecchymosis or edema of the eyelid.10-13

In this article, we present the surgical outcomes and complications after secondary implantation of a scleral-fixation foldable IOL, the PC 425Y 6/13.5 (Ophtec BV, Groningen, Netherlands), in aphakic vitrectomized eyes with topical plus subconjunctival anesthesia.

We reviewed the medical records of 18 aphakic vitrectomized eyes (Table 1) that underwent scleral fixation of a foldable IOL. Of the eyes, three had proliferative vitreoretinopathy, nine had traumatic retinal detachment, and six had an intraocular foreign body. Secondary implantation of a scleral-fixation posterior chamber foldable IOL (Ophtec PC 425Y 6/13.5) was planned after the retina was reattached without reproliferation and stable for a minimum of 4 months.

The same surgeon (Manuel Monteiro, MD) performed all procedures using topical anesthesia and four to six administrations of oxibuprocaina eyedrops. All patients underwent identical preoperative pharmacological preparation with cyclopentolate 1%, phenylephrine 10%, flurbiprofen 0.3 mg/mL, and ofloxacin drops, administered three times at 10-minute intervals until 45 minutes before the procedure.

Forty-five minutes before surgery, patients received oral diazepam 10 mg. Five minutes before surgery, Dr. Monteiro injected 0.15 mL of subconjunctival local anesthesia induced by lidocaine 2%.

After administering local anesthesia, the surgeon created a limbus conjunctival flap at the 5- and 11-o'clock positions. A radial scleral incision was made 3 mm perpendicular to the limbus, again at the 5- and 11-o'clock positions (Figure 1A). The infusion cannula was placed in the anterior chamber through the clear cornea, 1.5 mm from the limbus in the inferotemporal quadrant, to maintain intraocular pressure (IOP) during surgery. Using a 30-gauge needle, the surgeon created a scleral layer pathway approximately 1.5 mm behind the posterior surgical limbus. The extremity of the 10-0 Prolene needle was passed opposite the pointed one, through the scleral pathway, until it was seen in the pupillary area (Figure 1B). The surgeon then pulled the Prolene thread externally through the clear corneal incision and extracted the Prolene needle by reversing it through the incision. The extremity of the folded thread was brought through the haptic hole (ie, sailor's stitch; Figure 2), and the IOL was fixed to the sclera with an intrasscleral suture knot (Figure 3), or a stitch made on the outward side of the scleral incision. A scleral incision suture (7-0 Dexon) was made followed by a conjunctival flap suture. Inadequate wound sealing was sutured with a single 10-0 nylon stitch. Dexamethasone sodium phosphate and gentamicin antibiotic were injected subconjunctivally at the end of the procedure.

Once the procedure was complete, Dr. Monteiro recorded any verbal expression of pain the patient made during surgery. Rating the pain on a scale of 1 to 5, the surgeon also estimated the amount of pain the patient felt from tissue handling. Forty-five minutes after surgery, Dr. Monteiro then asked the patient to grade his levels of pain during surgery (scale, 0–10 visual analog pain scale).

The optic diameter of the PC 425Y 6/13.5 scleral-fixated foldable IOL is 6 mm and its length is 13.5 mm. The two haptics are made of PMMA. We used a new modified haptic perforated in the extremities (Figure 4). This scleral fixation foldable IOL can be inserted through a small clear corneal tunnel—on the epithelial surface, the incision is 3.5 mm; the endothelial face measures only 3.2 mm.

Patients' BCVA, autorefractometry and keratometry measurements, slit-lamp evaluations, Goldmann applanation tonometry, and fundus evaluation were examined at 2 days, 1 week, 1 month, and 4 months.

No patient required supplemental anesthesia to complete surgery safely. Analysis of the individual patients showed that 94% reported pain scores of 1 to 3, (ie, a slight sensation of tissue handling) during the operation; however, the surgeon only recorded that 11% of patients experienced pain at the end of the surgical procedure. No patient demonstrated a pain level higher than 3.

No epithelial defects were detected. The mean preoperative BCVA was 20/72 (range, 20/200–20/25); however, it was 20/40 or better in 70% of patients. Mean preoperative refraction was 10.60 D (range, 9.00–13.50 D) and mean preoperative astigmatism was 1.75 D (range, 0.50–4.00 D). At 4 months postoperative, 82.3% of patients achieved or maintained a BCVA of 20/40 or better, and the level of astigmatism did not differ significantly from the preoperative levels (mean, 1.65 D; range 0.50–2.75 D; P>.05).

The mean IOL power was 22.00 D (range, 18.00–25.00 D). Self-sealing wound adaptation occurred in 13 eyes, and the mean myopic shift by autorefractometry was -1.15 D. The mean endothelial cell loss at 4 months was 7.84% (range, 2.2–13.2%).

There were two microscopic hyphema that absorbed spontaneously and no suture slippage of the haptic was noted. One eye had irregular pupils, which we found to be related to traumatic iris. In all others eyes, the pupils were round and regular. On the second postoperative day, all corneas remained clear with only a mild inflammatory reaction in the anterior chamber.

There were no cases of IOL tilt, IOL decentration observed after dilation, or choroidal or retinal detachment. Peripheral anterior synechia restricted to the inferior quadrant was noted during gonioscopy in two eyes. Three eyes developed CME, which was successfully managed by subconjunctival corticosteroid injections. No other postoperative complications, such as suture exposure from the conjunctiva or secondary glaucoma, were observed.

Previous studies14,15 have found no significant differences in surgical conditions and intraoperative pain between topical and peribulbar anesthesia in cataract surgery; however, other studies have indicated that patients with dementia, deafness, or poor cooperation should be excluded from the use of this anesthesia.16 Over the past few years, we have modified our anesthetic and surgical techniques for scleral fixation of secondary IOL implants, now using a combination of topical and subconjunctival anesthesia as an alternative to traditional retrobulbar, subtenonal, or peribulbar anesthesia. This new method avoids the risks associated with peribulbar, sub-Tenon's, or retrobulbar anesthesia, such as periocular bruising or swelling, ptosis, optic nerve injury, orbital hemorrhage, central retinal artery or vein occlusion, brain-stem anesthesia, and even death.13 If conjunctival anesthesia is used, the anesthetic agents may also reach the iris and ciliary body.17

When using combined topical and subconjunctival anesthesia, the eye is left unpatched, and therefore postoperative visual recovery is immediate and ocular motility normal.14 Analysis of our data demonstrated that combining anesthesias is a safe and effective technique. In fact, patients reported low levels of pain, and we did not observe any increased surgical difficulties due to intraoperative pain. We also did not report any intraoperative complications.

Inserted through a smaller incision, the foldable IOL PC 425Y 6/13.5 boasts two important advantages: (1) Patients who receive a scleral-fixation IOL usually have a significant amount of astigmatism from their previous surgery. Operating through a small incision causes fast stabilization of the corneal wound and a precocious rehabilitation of visual acuity.18-20 (2) The procedure is performed in a relatively closed system, preventing intraoperative hypotony and enabling the surgeon to work more comfortably. There is also a lower risk for related complications, such as suprachoroidal hemorrhage and clinically apparent CME.21-23 Fast stabilization of the corneal wound can contribute to the stabilization of intraocular tension and low risk of choroidal hemorrhage, recurrent hemorrhages, and exogenous infections.21,24-26 No patient had postoperative complications resulting in permanent visual loss.

Our easy and effective IOL scleral fixation technique does not make the sclera fragile and lowers the percentage of intraoperative and late complications. The resistance of the fixation thread is increased because it uses a double thread, and the suture is passed from the external surface to the inside of the eye only once. We bury the free ends of the Prolene suture between the two edges of the scleral incision.

In conclusion, our experience demonstrates that topical plus subconjunctival anesthesia ensures optimum analgesia, permits a safe and comfortable surgical environment, and can be considered an evolutionary and valid alternative to traditional retrobulbar, sub-Tenon's, or peribulbar anesthesia in aphakic vitrectomized eyes. We are convinced that the simplicity of this technique makes it the anesthesia of choice in scleral fixation of a foldable IOL, such as the Ophtec PC 425Y 6/13.5. The perforated haptics make the procedure comfortable and less time-consuming for the surgeon. It provides the opportunity for the surgeon to work in a closed system. Because of the small study population, we recommended conducting a larger, long-term study.

The authors would like to thank Pinto Hespanhol for his contribution to statistical analysis.

Manuel Monteiro, MD, is with the Clinic of Ophthalmology, Antas, Porto and Faculdade das Ciências da Saœde, Beira Interior University, Covilhã, Portugal. Dr. Monteiro states that he has no financial interest in the products or companies mentioned. He may be reached at tel: +35 1919697816; e-mail: manuelmp@portugalmail.pt.

António A.P. Marinho, MD, PhD, is the Chairman of the Department of Ophthalmology, Hospital Arrábida, Porto Portugal. Dr. Marinho states that he has no financial interest in the products or companies mentioned. He may be reached at tel: +35 1936093345; e-mail: marin@mail.telepac.pt.

Salgado Borges, MD, PhD, is with the Department of Ophthalmology, San Sebastião Hospital, Porto, Portugal. Dr. Borges states that he has no financial interest in the products or companies mentioned. He may be reached at tel: +35 1968079450; e-mail: salgadoborges@hotmail.com.

Lucas Ribeiro is with the Department of IT, Vila Real Hospital, Vila Real, Portugal. Mr. Ribeiro states that he has no financial interest in the products or companies mentioned. He may be reached at tel: +35 1962145330; e-mail: lucas@chtmad.min-saude.pt