|Year : 2003 | Volume
| Issue : 2 | Page : 147-154
Phacoemulsification in subluxated cataract.
MR Praveen, Abhay R Vasavada, R Singh
Iladevi Cataract and IOL Research Centre, Ahmedabad, India
M R Praveen
Iladevi Cataract and IOL Research Centre, Ahmedabad
Source of Support: None, Conflict of Interest: None
Purpose: To evaluate the outcome of phacoemulsification in eyes with subluxated cataract.
Materials and Methods: This retrospective study comprised 22 eyes of 20 consecutive patients with subluxated cataracts of varying aetiology operated between March 1998 and March 2001. Detailed preoperative assessment included visual acuity (VA), slitlamp examination, presence of vitreous in anterior chamber, extent of subluxation, intraocular pressure (IOP) and detailed fundus examination. Phacoemulsification was done to retain the natural bag support and all patients had acrylic foldable Acrysof IOL implantation either in-the-bag or by scleral fixation. Postoperative observations included best-corrected visual acuity (BCVA), IOP, pupillary reaction and the IOL position.
Results: The aetiology of the subluxation was traumatic in 11 patients and non-traumatic in
9 patients. Fifteen were males and 5 were females. Mean follow-up was 11.7 ± 9.71 months (range
4-39). The average age was 39.15 ± 16.33 (range 5 - 74). A 2-port anterior chamber vitrectomy was performed in 6 eyes (27.2%). Capsule tension ring (CTR) was implanted in 15 eyes (68.18%). Twelve eyes (54.5%) had in-the-bag implants, while 5 (22.72%) had scleral fixation. The remaining 5 eyes (22.72%) had one haptic in-the-bag and another sutured to sclera. No major intraoperative complications were noted. Twelve eyes (54.5%) had clinically and geometrically well centered IOLs while 9 eyes (40.9%) had geometrically decentered IOLs. One patient was lost to follow-up. Fifteen eyes (55.55%) had postoperative BCVA of 6/12 - 6/6 while 2 eyes (7.40%) had BCVA of
6/18. The remaining 4 eyes (14.81%) had less than 6/24 BCVA due to pre-existing posterior segment pathology. Postoperative complications included rise in IOP in 1 eye (4.54%), pupillary capture of the IOL optic in 2 eyes (9.09%); the same 2 eyes (9.09%) required redialing of IOL. One eye (4.54%) had to undergo refixation (one haptic was fixed to sclera) year after cataract surgery. Postoperative retinal detachment was noticed in one patient after a month of phacoemulsification.
Conclusion: In subluxated cataracts it is essential to have appropriate parameters depending on the grade of cataract. This contributes to a safe and predictable outcome in subluxated cataract surgery.
Keywords: Subluxation, vitrectomy, capsule IOL in-the-bag implantation, scleral fixation
|How to cite this article:|
Praveen M R, Vasavada AR, Singh R. Phacoemulsification in subluxated cataract. Indian J Ophthalmol 2003;51:147-54
Surgical management of subluxated cataract presents a challenge to anterior segment surgeons. With recent advances in equipment and instrumentation, better surgical techniques and understanding of fluid dynamics, the surgeon is able to perform relatively safe cataract surgery in the presence of compromised zonules.
We would like to describe our experience of surgical strategies of phacoemulsification and lens implantation in subluxated lens. The primary objective of the study was to assess intraoperative risks and postoperative outcomes of phacoemulsification with implantation of IOL in patients with subluxated cataract.
| Materials and Methods|| |
Our retrospective study included 22 eyes of 20 consecutive patients with subluxated cataract. We divided our patients into 2 major categories: traumatic (T) and non-traumatic (NT). Data retrieved from the case records of these patients included age, gender, the cause of subluxation, refractive error, and preoperative visual acuity. The slitlamp examination included anterior chamber depth, pupil for presence of traumatic mydriasis, presence or absence of vitreous in anterior chamber, presence or absence of zonules, and type and grade of cataract. Cataracts were classified as Type-I nuclear sclerosis, Type-II anterior cortical. Type-III posterior cortical, and Type-IV posterior subcapsular cataract. Cataract density was graded as G1-2 Soft, G3-4 Hard, and G5 Brunescent. The extent of subluxation was also documented in terms of quadrant involvement in clock hours. IOP was measured with the Schiotz tonometer. Fundus examination included direct and indirect ophthalmoscopy, slitlamp biomicroscopic examination with +90D. Keratometry, axial length, 'A' Scan biometry and ultrasound 'B' Scan was done for retinal evaluation in a majority of patients. Patients' characteristics are described in [Table - 1].
In all patients maximum mydriasis was achieved with cyclopentolate 1% eye drops and phenylephrine 10% eye drops instilled 2 hours before surgery. All patients were given peribulbar anaesthesia. No digital massage was given. All surgeries were performed by a single surgeon (ARV).
We followed the closed chamber technique, which is achieved only by phacoemulsification. Our surgical paradigms included a 3-plane valvular incision, injection of viscoelastic in anterior chamber before removing any instrument from the eye, bimanual irrigation and aspiration and 2 port anterior chamber vitrectomy.
Temporal location was preferred irrespective of the site of subluxation. Before initiating capsulorhexis the anterior chamber was deepened with injection sodium hyaluronate 1.4% (Healon GV®/Pharmacia). A side entry was made at 2 and 3 o' clock positions away from the main incision using a 15-degree paracentesis knife. An initial small anterior capsulorhexis was attempted and then a definitive large rhexis (I & D rhexis),, was performed after capsulorhexis and before hydrodissection. Greishabers flexible iris retractors [Greishaber&CO AG] were used [Figure1]a, b. These were positioned parallel to the iris plane through small, short tract, peripheral paracentesis. The hooklets were placed around the edge of the anterior capsulorhexis. The stop on the hook was adjusted to hold the rhexis edge to the scleral wall. Thorough, gentle but careful multiquadrant hydrodissection was performed. Phacoemulsification [Legacy and Mackool microtip 25° bend (Alcon, USA)] was performed using power appropriate for the grade of cataract, low vacuum and aspiration setting with minimal bottle height - a slow motion phaco technique developed by Cionne and Osher and Buratto et al. Constant anterior chamber depth was maintained with 2% HPMC injection (Viscomet, Sun Pharmaceuticals India Ltd.) during phacoemulsification and also before removing any instrument from the eye. The tip of the phaco probe was directed at the 6 o'clock position. Initial sculpting parameters included appropriate power depending on grade of cataract, 12 cc flow rate and 40 mm Hg vacuum. Later our technique of step-by-step chop in situ and lateral separation followed by stop-chop-chop and stuff was performed. The step down principle was used for fragment removal ( Endless endeavour for endocapsular phacoemulsification, a video film presentation at the American Society of Cataract and Refractive Surgery, Vasavada et al, Boston, 2000).
Detection of vitreous in the anterior chamber at any stage of operation was handled by a thorough 2-port anterior chamber vitrectomy. The presence of vitreous was recognised by plugging into the phacoprobe during cortical clean up. Lens material could not be aspirated even with aggressive suction levels in the presence of vitreous. Thorough anterior chamber vitrectomy was confirmed by internal sweeping of the iris with the iris spatula from each port to rule out the probable entry of vitreous strands into the incision. The remaining cortex was removed by bimanual irrigation and aspiration with low aspiration flow rate, minimal bottle height and appropriate vaccum. In young patients with soft cataracts it was not possible to chop, we aspirated the nucleus with a phaco probe and removed the residual cortex by bimanual irrigation and aspiration.
Our main aim was to retain the natural bag support for placement of IOL. CTR was inserted only after removal of the residual cortex. We did not adapt any specific measurement for insertion of CTR - (Type 1 B NONE D Morcher) except for axial length. Before inserting the CTR we injected Healon GV ® just under the anterior capsulor-hexis to create a path for the CTR insertion. CTR,,,,, of 10.0 mm/12.0 mm diameter ring (Morcher type 14) was used to maintain the stability and stretch of the capsule during IOL implantation. In some cases the ring was implanted by simple suture tie forceps and in others with shooter [Hans Geuder, Heidelberg, Germany], CTR was introduced through the main incision. Acrysof MA 30 BA or SA 60 AT (Alcon, USA) was implanted in all patients, either in-the bag or by scleral fixation. In eyes with total anterior dislocation of the lens, and in cases where we could not retain the bag during phacoemulsification, we performed scleral fixation. For scleral fixation we performed conjunctival peritomy at 2 sites, first from 12.00 to 12.30 in the superior quadrant and then 6-6.30 in the inferior quadrant. Next, scleral pockets or flaps were created in these quadrants. Later 10/0 polypropylene sutures were threaded on a side cutting straight needle at one end and a curved needle at the other end. The first straight arm passed under the scleral pocket 1.0 mm posterior to the limbus. The 26-gauge needle was bent at its quarter length and passed through the opposite end, under the scleral pocket. The straight needle passed behind the iris and across the pupil and was threaded into the receiving 26-gauge bent needle. The 26-gauge needle was then retracted with the suture needle. The thread inside the chamber was pulled halfway out of the eye and the cut end attached to the straight needle was tied to the leading haptic and the end attached to the curved needle was tied on the trailing haptic. The optic was then folded and inserted in the eye. Once the leading haptic and half of the optic were behind the iris, the optic was unfolded. As the Acrysof lens unfolds slowly, it can be pushed behind the iris before it completely unfolds. The straight armed needle suture was then pulled to position the leading haptic. The trailing haptic that was outside the eye was grasped and looped with a McPherson forceps and placed behind the iris. The sutures were fastened to the sclera. The scleral flaps and the conjunctival peritomy were closed with 10-0 nylon.
The residual viscoelastic was then thoroughly removed. The main incision and paracentesis site were sutured with 10/0 vicryl sutures. Intracameral 1 ml 0.5% Pilocarpine nitrate and 1% 0.3 ml. Vancomycin were administered. Postoperatively all patients were given 1% Prednisolone acetate eye drops along with 0.3% Ciprofloxacin eye drops, 0.5% Timolol Maleate and Diclofenac sodium eye drops. Systemic corticosteroid (oral Prednisolone) was given to all patients in tapering doses of 1 mg/kg. body weight per day. Systemic anti-inflammatory drugs were given if indicated in the postoperative eye examination.
Postoperatively patients were examined on the first day, and at one week and one month [Figure - 2][Figure 3]. Every follow-up included a thorough slitlamp examination, IOP, Best Corrected Visual Acuity (BCVA), centration of IOL, and fundus examination. A clinically and geometrically well-centered IOL was defined as no optic edge identified in undilated pupil and clinically well-centered but geometrically decentered IOL, was defined by difference in distance from the optic edge to the limbus on both sides of the IOL. Patients' postoperative follow-up is given below [Table - 2]. The results were documented by slitlamp videography at every visit.
| Results|| |
Our retrospective study includes 22 eyes of 20 consecutive patients. Nine eyes were in the traumatic category and 13 eyes in the non-traumatic category. Fifteen patients were males and 5 females. The mean age was 33.15 ± 16.33 (range 4-39). Two patients had primary open angle glaucoma and had received trabeculectomy prior to cataract surgery. One patient had traumatic angle recession glaucoma and was given Timolol maleate eye drops 0.5% twice daily with well controlled IOP.
Preoperative anterior chamber depth was 3.27±1.22 mm. Postoperative IOP was normal in all patients. None of the eyes with non-traumatic subluxation had vitreous disturbance. Four eyes with traumatic subluxation had broken anterior vitreous face. Two of these eyes had vitreous in the anterior chamber. Traumatic mydriasis was noted in 6 eyes. Eleven eyes had temporal subluxation, 8 eyes had nasal subluxation, and 3 had total dislocation of lens. Three eyes had no zonules at the area of subluxation. The mean degree of subluxation was 5.05 ± 1.99 clock hrs. with range 90-240°. Three eyes had more than 200° of subluxation.
On fundus examination two eyes with non-traumatic subluxation had non-pigmented lattice degeneration of 3 clock hours anterior to equator. Three eyes with non-traumatic subluxation had high myopic fundus and one of them had inferotemporal choroidal coloboma. Two patients with traumatic subluxation had vitreous haemorrhage in the lower periphery, although B-scan revealed no abnormality. One eye with traumatic subluxation had a horseshoe tear at 5 clock hours and was advised laser photocoagulation after cataract surgery. The fundus in other patients was within normal limits.
Fifteen eyes had endocapsular phacoemulsification while bimanual I/A was performed in 7 eyes. A two-port anterior chamber vitrectomy was performed in 6 eyes of which 2 of traumatic group had vitrectomy prior to anterior capsulorhexis and phacoemulsification and the other two had vitrectomy during phacoemulsifi-cation. The remaining 2 eyes were in non-traumatic group and required mandatory vitrectomy due to total anterior dislocation of the lens. CTR was implanted in 15 eyes (68.2%). In 2 eyes CTR was attempted but had to be aborted due to anterior capsule tear. Seventeen eyes (77.3%) had acrylic foldable multi-piece lens while 5 eyes had acrylic foldable single piece lens fixated. Twelve eyes (54.5%) had in-the-bag implant and five (22.7%) eyes had scleral implant. The remaining 5 eyes (22.7%) had one haptic in the bag and another sutured to the sclera. No serious intraoperative complications like vitreous loss, dropped nuclear fragment or further zonular dialysis were noticed during surgery. Postoperative complications included rise in IOP on the second postoperative day in one eye, pupillary capture of the IOL optic in 2 eyes (9.09%) on the first postoperative day, requiring redialing of the IOL. One eye had to undergo refixation (one haptic was fixed to the sclera) after a year of cataract surgery. Postoperative retinal detachment was noticed in one patient after a month of phacoemulsification. There was no further distortion of pupil noted postoperatively. Postoperatively, the IOP was within normal limits in all cases. Twelve eyes (54.5%) had clinically and geometrically well centered IOL while 9 eyes (40.9 %) had geometrically decentred IOL. We lost one patient to follow-up. Fifteen (55.55 %) eyes had postoperative BCVA of 6/12 - 6/6 while 2(7.40%) eyes had BCVA of 6/18. The remaining 4 eyes had less than 6/24 BCVA due to pre-existing posterior segment pathology.
One patient with traumatic subluxation with horseshoe tear postoperatively was sealed with laser photocoagulation after a month of cataract surgery. Another patient with postoperative retinal detachment underwent retinal retachment surgery.
| Discussion|| |
The management of subluxated lenses has remained a controversial issue for many years. Jarret retrospectively analysed the indications for surgical intervention in a series of 114 cases of subluxated or dislocated lenses. Both intracapsular and extracapsular cataract extraction (ECCE) have been documented for the management of subluxated lenses. Techniques used include discission, aspiration and cryoextraction. Recently, several authors have reported using pars plana lensectomy for subluxated lenses with good surgical outcome. , In recent years, transscleral suture fixation of posterior chamber IOL has become an alternative to anterior chamber IOL implantation in eyes lacking capsular support.
Our surgical paradigm of closed chamber technique was invaluable. Temporal corneal tunnel was preferred for reasons of surgeon comfort and convenience. Many surgeons locate the incision away from the area of the subluxation. We did not feel this was necessary. We strictly adhered to the principle of I&D rhexis,, and care was taken to stay away from the site of subluxation. It was most helpful because it prevented fibrosis of the capsule and further decentration of IOL along with the capsular bag. Secondly, initial small rhexis helped to restrict the turbulence in the bag and prevented vitreous aspiration during phacoemulsification. Iris retractors were used to temporarily support the dialysis for safer phacoemulsification and IOL placement [Figure - 1]a,b. It also stabilised the bag. Thorough but gentle multiquadrant hydrodissection helped us reduce the stress on the zonules during phacoemulsification. Secondly it helped in thorough cortical clean up and prevention of posterior capsule opacification. No deliberate hydrodelineation was performed. The Kelman tip has a 25° downward bend at the front portion of the needle, and creates a groove without any downward or forward force on the nucleus, thereby reducing the stress on the zonules. We believe that with appropriate power, low vacuum and aspiration flow rate with reduced bottle height causes minimal turbulence. Injection of disperserve viscoelastic was mandatory before removal of any instrument from the eye to prevent the posterior capsule from moving forward. Endocapsular phacoemulsification with our phaco technique allowed nucleus division with minimal stress on the capsular bag and produced multiple small nucleus fragments that were easy to consume in the central space. Using the stop-chop-chop and stuff technique and stepdown technique with smaller fragments helps to keep the flow and vacuum rates at safe levels, thus preventing inadvertent capsule touch and vitreous prolapse. It was mandatory to perform vitrectomy in presence of vitreous before or during phacoemulsification. It is an established fact that contingent vitrectomy prevents any traction on the vitreous base and peripheral retina which may lead to retinal detachment and macular oedema. Bimanual I/A was performed to maintain a closed chamber. By using a low aspiration flow rate and low bottle height we maintained minimal turbulence within the anterior chamber and minimised the anterior chamber depth fluctuation. In our study, the CTR was found to be useful. The confirmation of the ring in the bag included dramatic expansion and stabilisation of the bag. Presence of CTR in the bag was visualised by retracting the iris. It enhanced safety and efficacy during phacoemulsification and IOL implantation, maintained the circular contour of the capsular bag and avoided collapse of the bag after the lens was removed from the capsule. It also provided additional support to the bag by pushing the bag equator to the original position or beyond to help prevent IOL decentration and capsule contraction.,,,,,, We noticed that on longterm follow-up, with in-the-bag fixation and with CTR, the IOL was well centered due to capsule stretching, stability and support. Scleral fixation,, was attempted in cases where we could not retain the natural bag support during phacoemulsification and also in eyes where we could not achieve good centration even after implantation of CTR. We used AcrySof for scleral fixation in spite of availability of specially designed PMMA scleral fixated intraocular lens. We preferred AcrySof due to its easy insertability through a small incision and as well as its superior bio-compatibility.
Eyes with pupillary capture had one haptic in-the-bag and another haptic sutured to sclera. This asymmetrical fixation might be the reason for decentration of IOL. Paracentesis incisions and the main incision were sutured to prevent wound leak arising from low scleral rigidity. We preferred vicryl sutures to avoid subsequent removal.
All patients postoperatively received timolol maleate 0.5% eye drops twice daily, with systemic anti-inflammatory and steroids due to increased incidence of uveal inflammation, transient rise in intraocular pressure and macular oedema.
In summary, we could achieve in-the-bag implantation in most eyes due to application of the closed chamber technique, which allowed us to retain the natural bag support till the end of phacoemulsification. We could implant IOLs in all eyes. No major intraoperative complications were noted. The endocapsular ring in some eyes did not correct for centration of IOL. In these cases, Cionni Ring, (Type 1L NONE MORCHER, MCTR could be another alternative for better centration and stability of the bag and IOL.
In conclusion, using appropriate phaco power depending on grade of cataract is essential. This must be accompanied by low aspiration flow rate, low vacuum and low bottle height which together cause minimal turbulence in the anterior chamber. This provides a safe and predictable outcome in subluxated cataract surgery.
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[Figure - 1], [Figure - 2]
[Table - 1], [Table - 2]
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