Anterior Chamber Intraocular Lens in Posterior Capsular Rent




 Choyce Blue, Double Ext. Loop



In 1956, the Choyce inferior bulge brown haptic AC-IOL (with 4.0 mm optic) was introduced; later the Choyce Mark I and II modifications of Strampelli’s implant were available.

Following the results of an FDA clinical trial, on December 11, 1981, the study lenses – the Choyce Mark VIII and Mark IX anterior chamber designs – became the first lenses to be approved by the FDA as safe and effective. Around this time, Rayner engraved the dioptric power of lenses on the margin of the optic surface (Figs. 21.1 and 21.2).

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Fig. 21.1
(af) Early types of AC-IOLs. AC-IOLs of rigid, closed-loop, and small optic caused several postoperative complications, and many of these lenses had to be removed. (a) Boberg-Ans four-loop lens (Rayner) ​new.​eyeantiques.​com/​shop/​eye-surgery/​intraocular-lenses/​. (b) Cogan’s variation of Boberg-Ans flexible loop AC lens ​new.​eyeantiques.​com/​shop/​eye-surgery/​intraocular-lenses/​. (c) Epstein iris collar stud lens ​new.​eyeantiques.​com/​shop/​eye-surgery/​intraocular-lenses/​. (d) Large Strampelli lens ​new.​eyeantiques.​com/​shop/​eye-surgery/​intraocular-lenses/​. (e) Choyce Mark VIII ​new.​eyeantiques.​com/​shop/​eye-surgery/​intraocular-lenses/​. (f) Choyce Mark IX (Rayner Catalog 496) ​new.​eyeantiques.​com/​shop/​eye-surgery/​intraocular-lenses/​


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Fig. 21.2
(ab) Dannheim AC-IOL in place. Note slightly oval pupil along the IOL axis and large iridectomy. Cornea is clear

In 1987, Smith et al. found an increasing number of eyes with closed-loop, semi-flexible anterior chamber implants with decreased vision due to corneal oedema and persistent cystoid macular oedema. They evaluated 53 such eyes in 52 patients who presented with decreased vision 1–51 months (average, 15 months) after lens implantation. The most frequent lens implanted was the Surgidev Style 10 Leiske IOL. Surgery for IOL removal or exchange with or without penetrating keratoplasty was performed in 34 (64 %) of 53 eyes; visual acuity recovery ranged from 20/20 to hand motions (average, 20/80). Despite clear corneal grafts in 24 (92 %) of the 26 eyes that underwent corneal transplantation, visual acuity of 20/40 or better was obtained in only 9 eyes (26 %). Based on the intractable inflammatory sequel associated with the anterior chamber closed-loop IOLs, they strongly urged discontinuation of their use [12] (Fig. 21.3).

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Fig. 21.3
(ac) Bullous keratopathy after different types of rigid AC-IOL implantation

In 1987, Apple et al. analysed 606 surgically removed anterior chamber intraocular lens specimens. This study revealed that 351 or 58 % of these were small-diameter, round loop, closed-loop styles. Because of the extremely high percentage of IOLs with this design and the correlation of clinical histories with their histopathology findings, they have concluded that such IOLs do not provide the safety and efficacy achieved by other anterior chamber lens designs. The finely polished, one-piece, all-PMMA styles fared well in their study. They concluded that implantation of anterior chamber lenses with small-diameter, round, closed loops is no longer warranted. Patients in whom these IOLs have already been implanted should be carefully followed. It was their opinion that the FDA should recall or closely monitor all IOLs of this design and that implantation of closed-loop lenses should be discontinued in the United States. Furthermore, they believed that an IOL deemed to be not medically sound or worthy of implantation in the United States should not be marketed or donated outside of the country [13] (Fig. 21.4).

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Fig. 21.4
(ac) Bullous keratopathy of a 61-year-old male 8 years after AC-IOL implantation (a) 1 day (b) and 1 month (c) after perforating keratoplasty combined with AC-IOL removal and PC-IOL implantation (with ciliary sulcus suture fixation). Visual acuity improved to 0.4

In another publication, Apple et al. found clinicopathological data to assist ophthalmologists in choosing a safe and efficacious anterior chamber intraocular lens. Two important factors that have led to an increased success rate with some anterior chamber IOL styles are (1) attention to lens design and (2) attention to modern manufacturing and lens finishing techniques. In 1987, they knew much more about how to achieve appropriate lens flexibility, which decreased the need for perfect sizing. Increased attention had been given to the anterior-posterior vaulting characteristics of IOLs. This had reduced the incidence of various complications such as the intermittent touch syndrome and the uveal chafing syndrome. They recognized several design flaws in some lens styles. For example, there was a considerable decrease in the number of small-diameter, round-looped, anterior chamber IOLs being implanted, particularly those with a closed-loop configuration. Several problems had been and continued to be caused by some poorly manufactured anterior chamber lenses with sharp optic and haptic edges. They concluded that technology to assure smooth lens finishing and polishing was available and accessible to all manufacturers, and defective lenses should soon be a thing of the past [14].

Weene reported his results with flexible open-loop anterior chamber intraocular lens implants in cataract surgery complicated by vitreous loss and in secondary implantation. Results were reviewed in 18 eyes in the former group and in 43 eyes in the latter group that were operated on over an 8-year period. He found that of 18 eyes in the former group, 13 (72 %) had a final visual acuity of 20/40 or better. Cystoid macular oedema was the most common cause of the decrease in visual acuity. Of 43 eyes in the latter group, 37 (86 %) had a final vision equal to the best-corrected preoperative vision. A retinal complication developed in 6 of 18 eyes that received a primary AC-IOL with vitreous loss, whereas no retinal complications developed in any of the 14 eyes that received a secondary AC-IOL with vitreous loss (P = 0.021). For secondary AC-IOL implantation, eyes with vitreous loss treated by Weck-Cel sponge (Beaver-Visitec Int., Waltham MA, USA) vitrectomy had the same visual results as eyes without vitreous loss. According to his opinion, flexible open-loop AC-IOLs are safe and effective for primary implantation after vitreous loss and for secondary implantation [15] (Fig. 21.5).

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Fig. 21.5
(ab) Modern flexible open-loop AC-IOLs in place. Note clear cornea, well-centered AC-IOL, round pupil, and small iridectomy

In their 1994 article, Auffarth et al. posed the question as to whether there are any AC-IOLs acceptable for clinical use in the 1990s. Of 4104 explanted IOLs they examined, 50 % were closed-loop designs (n = 2095/4104); 26 % (1100/4104) were miscellaneous, older designs; and 22 % (919/4104) were open-loop lenses. The most important complications were corneal pathology (2065/4104) and inflammation (1370/4104). Closed-loop designs were responsible for almost 80 % of corneal pathology, with an increasing complication rate with ongoing implant duration (P < 0.0001). Open-loop AC-IOLs showed, in relation to their normalized rate of implantation, a significantly lower rate of complications and explantations (P < 0.01). They concluded that complication rates of flexible, open-loop AC-IOLs are much lower than previously assumed. They should be distinguished clearly from most of the older AC-IOL designs. Consideration of these lenses as an alternative to sutured posterior chamber IOLs for secondary or exchange implantation may be warranted for selected clinical indications. They also could provide an alternative to the aphakic spectacle rehabilitation program in developing countries, which will have a positive impact on the overwhelming backlog of patients with cataract in the underprivileged world [16].

In 1998, Sawada et al. published the results of a long-term (mean 9 years 7 months) follow-up of primary anterior chamber lens implantation in 86 eyes. Fifty-three eyes received an open C-loop Simcoe AC-IOL (SAC3, Cilco), and 33 eyes received a four-point fixation (Kelman) AC-IOL. Although corneal endothelial cell density was less than 2000 cells/mm [2] in 57 % of the cases, the final visual acuity was 0.5 or better in 69 % of the eyes. Among postoperative complications, deformed pupil was revealed in 56 % and bullous keratopathy in 14 % of the cases, respectively. The AC-IOL was explanted due to these complications in 14 eyes, and 11 of these were the open C-loop Simcoe lenses [17].



21.3 Indications for “Primary” and “Secondary” AC-IOL Implantation in Case of Posterior Capsular Rent


In case of severe posterior capsule rent, and if the CCC is also compromised, implantation of an AC-IOL can be considered.

There are two options for the procedure: either “primary implantation” of the AC-IOL to complete the surgery in one session, or “secondary implantation” of the AC-IOL, when the patient is left aphakic for a certain period of time (usually a few weeks or months after the complicated primary procedure).

In case of complicated cataract surgery, I myself would prefer the “secondary” procedure (see Videos 21.1, 21.2, and 21.3), depending on the visual acuity of the fellow eye, and on the age, profession, and the general condition of the patient.

Why do I prefer secondary AC-IOL implantation? Because, in my opinion, it is safer and can be better planned.

In case of a severe posterior capsule rent, there are certain conditions against primary AC-IOL implantation;


  1. 1.


    The remaining cortex has to be completely removed, which is not always easy, as it is mixed with vitreous. Due to the manipulations, the pupil constricts, which makes the manoeuvre even more difficult. Iris hooks can be used to dilate the pupil or to keep it dilated. We have to rule out any dropped nucleus or cortex; otherwise, we have to continue with pars plana vitrectomy, or the patient has to be referred to a vitreoretinal surgeon.

     

  2. 2.


    Complete removal of the vitreous from the anterior chamber, from the wound, and from the pupillary plane is recommended.

     

  3. 3.


    We also have to take into consideration that today the cataract surgery through a 1.8–2.8 mm clear cornea wound is routinely performed under topical anaesthesia. For the rigid, usually 6.0 mm diameter optic AC-IOL implantation, it is recommended to perform a sclerocorneal wound of 6.0–6.5 mm, after opening the conjunctiva, and performing diathermy. The large wound as well as the conjunctiva needs suturing after the IOL is implanted. These steps cannot be performed under topical anaesthesia, but peribulbar (or general) anaesthesia is recommended.

     

  4. 4.


    In case of severe posterior capsule rent, when anterior vitrectomy has to be performed either with vitrectome or with a Weck-Cel sponge (Beaver-Visitec Int., Waltham MA, USA), the risk of expulsive haemorrhage is relatively high (especially in elderly patients with sclerotic vessels and known hypertension).

     

  5. 5.


    Other postoperative complications such as cystoid macular oedema (Irvine-Gass syndrome), retinal detachment, or even endophthalmitis may also occur more frequently in eyes with intraoperative complications, than in uneventful cases.

     

  6. 6.


    Ideally, it would be useful to know the anterior chamber depth and the endothelial cell count before AC-IOL implantation, but these parameters are not always known for routine phacoemulsification and foldable PC-IOL implantation.

     

  7. 7.


    Although informed consent is signed by the patients before surgery, the possibility of AC-IOL implantation is not always understood by them, and even medicolegal consequences may arise, if patients say that they were not well informed (e.g., about the long-term effect of AC-IOLs). In case of secondary AC-IOL implantation, we have enough time to discuss the pros and cons of AC-IOLs and the other possibilities as well.

     

  8. 8.


    Routine phacoemulsification with foldable PC-IOL implantation in an experienced hand takes 8–10 min. In case of posterior capsule rupture, when the consequences of the complication have to be treated (anterior vitrectomy), a large wound has to be performed and sutured at the end of surgery, and the procedure may take around 30 min. It may cause difficulties for elderly or scoliotic patients to lay flat for such a long time.

     

  9. 9.


    And finally, a surgeon’s experience is also an important factor, which has to influence his/her decision on AC-IOL implantation. AC-IOL implantation is not an easy procedure. Even for those surgeons who perform around a thousand phacoemulsifications annually, and all the steps of the surgery are in their hands, AC-IOL implantation can be a challenge.

     

An objective contraindication of the primary AC-IOL implantation procedure is, if we do not have the appropriate power AC-IOL on site, which might be the case especially in high myopic or hyperopic eyes.

Complications after primary and secondary AC-IOL implantation were also examined and published in an article of Fasih et al. in 2010. Out of 60 patients, 30 received primary AC-IOLs and the other 30 patients received secondary AC-IOL implantation after 2 months of complicated ECCE. BCVA and complications within 2 months were examined and compared. There was no statistically significant difference in BCVA; however, the first group had a total of 92 postoperative complications, while 30 eyes had 58 postoperative complications in the second group. Early transient corneal oedema was the commonest complication observed in both groups (60 % vs. 47 %), respectively in primary AC-IOL and secondary AC-IOL, followed by iritis (50 vs. 20 %), endothelial decompensation (27 vs. 10 %), while suture erosion, iridodialysis, and pseudophakic bullous keratopathy were observed in only primary AC-IOL group among one patient each. They concluded that the flexible open loop AC-IOLs are suitable for both primary and secondary implantations to correct aphakia. Secondary implantation of flexible open-loop AC-IOLs after complicated ECCE seems to have more favourable visual outcomes and lower complications rate than primary implantations in complicated ECCE cases [11]. In terms of visual acuity results, Uzma et al. and David et al. also found more favourable outcomes in cases of secondary AC-IOL insertion following complicated ECCE than the case with primary IOL implantations [11, 18]. Patients undergoing secondary AC-IOL implantation are presumably healthier group of eyes that have been preselected on the basis of their visual potential, absence of inflammation, glaucoma, or anterior chamber abnormalities, including peripheral anterior synechiae [11]. Weene reported no retinal complications after secondary implantation cases. He proposed that this might be due to vitreous liquefaction and posterior vitreous detachment that occurs in most cases of aphakia, especially after 1 year [15].


21.4 Contraindications for AC-IOL Implantation


Eyes with shallow anterior chamber depth are not appropriate for AC-IOL implantation. With the implantation of the Artisan hyperopia phakic lens, there was a significant negative correlation between anterior chamber depth and endothelial cell loss. Two out of 13 patients experienced posterior synechiae with pigment deposits in both eyes. More attention should be paid to shallow anterior chambers during the preoperative screening to avoid unnecessary complications [19]. Dick advises to use ciliary sulcus suture-fixed PC-IOLs instead of AC-IOLs in cases of shallow anterior chamber and anterior synechiae. In his opinion, AC-IOL implantation is not appropriate for eyes with compromised cornea, peripheral anterior synechiae, shallow anterior chamber, or glaucoma [20].

Vitreous in AC and in the papillary plane has to be completely excised either with Weck-Cel sponge (Beaver-Visitec Int., Waltham, MA, USA) and scissors or preferably with using a vitrectomy instrument. It is advised to use a bimanual setting, when the infusion is separated from the cutting edge, avoiding continuous hydration of the vitreous. The best way to remove all the vitreous is from behind the iris, through a pars plana incision, and the infusion is through the corneal wound.

According to a study in eyes that have vitreous loss and thorough anterior vitrectomy, AC-IOL implantation did not appear to increase the incidence of retinal detachment [21].

Endothelial cell count less than 1000 cells/mm2 was considered to be a contraindication of secondary IOL implantation in the late 1970s [22], as a mean endothelial cell loss of 15.6 % after secondary lens implantation was demonstrated [23]. Today, with the modern flexible AC-IOLs, with the use of new ophthalmic viscosurgical devices (OVD), and applying the soft-shell technique by Steve Arshinoff [24], we might perform secondary implantation after counselling with the patients the potential negative consequences, and the potential need for further surgical intervention, such as endothelial lamellar keratoplasty.

Uveitis in the history: Active uveitis is an absolute contraindication for AC-IOL implantation. In chronic uveitis (often associated with rheumatoid arthritis or other autoimmune diseases), it is mandatory to perform the surgery (either primary or secondary AC-IOL implantation) after a 3–4 months remission of the inflammation. This can be achieved with local (topical) and systemic corticosteroid treatment.

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Aug 12, 2017 | Posted by in OPHTHALMOLOGY | Comments Off on Anterior Chamber Intraocular Lens in Posterior Capsular Rent
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