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Dr.Nagendra Shekhawat,Dr.JITENDRA KUMAR BAGARIA,Dr.Karishma Goyal,Prof.Kamlesh Khilnani

Introduction

Planned intracapsular method of cataract extraction, [1] extracapsular cataract extraction complicated by marked zonular dehiscence or a large posterior capsular break without an intact capsulorhexis or traumatized eye, [2] Ectopia lens or pediatric lensectomies, these all resulted in an absence of capsular support, ultimately causing aphakia. Visual rehabilitation in such patients is quite challenging not only due to the visual outcome but also to the related complications in the post-operative period. Usual modalities accomplished in the past are the spectacles, contact lens or implantation of Anterior chamber IOL (ACIOL), iris fixated IOL or Scleral fixated IOL (SFIOL). [3] Spectacles & contact lens have limited use due to their complication profile. [4, 5] Then came the concept of intraocular lens implantation. [6]

The endocapsular placement is the most preferred anatomical site for IOL placement. Thus, placement of the IOL in the posterior, rather than the anterior chamber reduces the risk of damage to anterior chamber angle structures & corneal endothelium. [7]. In this regard, we will be analyzing mainlythe complications and visual outcome of SFIOL and posterior iris claw lenses to find the efficacy of each

lens by comparing with each other.

Material and method

The ethical committee of the hospital approved the study. It was a comparative study of 60 cases with 30 in each group. All aphakic patients above 12 years who were ready to give consent were included in the study. Exclusion criteria included patients with corneal opacity, retinal disorder, optic atrophy, bleeding disorder, pregnancy & those who were unwilling to give consent. Preoperative & post-operative visual acuity, Slit lamp & Fundus examination, Applanation tonometry, Keratometry, Biometry), optical coherence tomography (OCT) was done for extensive evaluation of anterior & posterior segment.Scheimpflug imaging was done to evaluate proper centration of IOL. Follow up was done on 1st, 7th, 28th post-operative day, at 3 month & 6 month.

Surgical technique

Iris claw

5.5mmcorneoscleral tunnel made at 12o’clock position.The width of incision should be 5.5mm. The IOL was inserted into anterior chamber with the convex side downwards (upside down) holding it in the forceps. With a manipulator, the IOL was brought into the horizontal position from 3o’clock to 9o’clock. After bringing the IOL behind the iris and the pupil was constricted, the IOL was tilted slightly in order to show the contour of the “claws” through the iris stroma. A dialler was inserted and exerts gentle pressure on the slotted centre of the lens haptic, the “claw”. Surgical peripheral iridectomy was done intraoperatively.

SFIOL

Under Peribulbar anesthesia, 5.0 mm conjunctival peritomy was done at the 2 o’clock and 8 o’clock positions. Then, 2 T-shaped incisions (1.5-2 mm long) were made 1.5-2.0 mm from the limbus and depth was half of scleral thickness, exactly 180 degrees apart diagonally. An infusion cannula or anterior chamber maintainer was inserted.  To prevent interference with the creation of the T-shaped incision, infusion cannula should be positioned at 4 o’clock. Anterior vitrectomy (deep core) was performed, if necessary. Sclerotomy was done parallel to the iris at the T-shaped incision with a 23-gauge angled microvitreoretinal (MVR) knife and a scleral tunnel (3-3.5 mm long) was made parallel to the limbus at the branching point of the T-shaped incision. 2.8 mm keratome was used to make a corneal incision at 10 o’clock through which IOL, with overall diameter 13 mm and optic diameter 6 mm, was implanted with an injector; the trailing haptic was left outside the incision. The tip of the haptic was then grasped with 24/25-gauge IOL haptic gripping forceps, pulled through the Sclerotomy, and externalized on the left side. After the trailing haptic was inserted into the anterior chamber& the haptic tip was grasped with a 24/25-gauge forceps, pulled through the second sclerotomy and externalized on the right side. The haptic insertion into the anterior chamber may be difficult depending on the material or shape of the haptics, which can cause the IOL to rotate clockwise and the leading haptic to slip back into the eye. To prevent such risks, the IOL optic was pushed to the back of the iris and moved to the 2 o’clock position with a push-and-pull hook inserted through the side port at the 1 o’clock position. The tip of the haptic was subsequently inserted into the limbus–parallel scleral tunnel.

Results

The patients were matched in terms of age, sex, laterality. Age group in both the groups ranged from 37-75 years. The majority of patients in both the groups were in the 50-70 years age group. Mean age in iris claw group was 57.25 years and in SFIOL group was 58.88 years.

Most common etiology of aphakia in our study was post complicated cataract surgery. Majority patients in our studywere treated within 0-1 years of aphakia. Maximiumnumber of patients had uniocular aphakia with good vision in the fellow eye.In this study out of 60,25 were due to complicated cataract surgery, 2 were aphakic after ICCE. These cases underwent deep core vitrectomy + secondary IOL fixation (SFIOL or Iris claw fixation). Rest of the cases included dropped IOL(4), subluxated cataractous lens(5), posttraumatic subluxated IOL(2), subluxated  crystalline lens(2),posttraumatic subluxated cataractous lens(3),nucleus drop(6),dropped IOL(5),posttraumatic dislocated  IOL(1),posttraumatic dislocated cataractous lens(3),posttraumatic dislocated crystalline lens(1),cortical matter in vitreous cavity(1). In these cases 23-gauge primary pars plana vitrectomy with 360 endolaser was done. Then secondary IOL implantation was done.

LogMAR BCVA of preoperative and postoperative in both the groups were compared and the difference was found to be statistically significant. Postoperatively IOP was slightly higher in iris claw fixation group in comparison to scleral fixation group

Surgical time was 18.57+1.48 minutes in iris fixation group and 43.67+3.02 minutes in SFIOL group. So surgical time was significantly less in iris claw fixation group.

Change in corneal astigmatism & pupil peaking & pigment release was more in ICIOL group.

Complications Day 1 Day 7 Day 28 3 month 6 month
SFIOL IRIS CLAW FIXATION SFIOL IRIS CLAW FIXATION SFIOL IRIS CLAW FIXATION SFIOL IRIS CLAW FIXATION SFIOL IRIS CLAW FIXATION
Corneal edema and anterior chamber reaction 1 (3.33%) 6 (20%) 0 0 0 0 0 0 0 0
Decentration 0 3 (10%) 1 0 0 3 0 3 0 3
Raised IOP 0 0 2 (6.66%) 2(6.66%) 0 0 0 0 0 0
Ovalling of pupil 0 4(13.33%) 0 0 0 0 0 0 0 0

Discussion

ACIOL and SFIOLs have been the most popular type of IOLs used in implantation in the absence of adequate capsule support, and they avoid the need for aphakic spectacles or contact lenses. However, there is much discussion on the best method for secondary IOL implantation that offers the lowest complication rate and best possible visual rehabilitation over several years.

Surgical time was 18.57+1.48 minutes in iris fixation group and 43.67+3.02 minutes in SFIOL group. So surgical time was significantly less in iris claw fixation group but iris claw implantation was less demanding in view of surgical skills then SFIOL. Scleral incision, tunnel formation and retrieval of loop from vitreous cavity needed more surgical skills and time. Hara et al. (2011) stated similar results. They stated that the mean surgical time in the Iris fixation IOL group (20.0 ± 8.9 min) was significantly shorter than that in the scleral fixation group (49.7 ± 18.9 min) (P < 0.0001) [8].

Pupil ovalization was the more common complicationin our study in ICIOL, among

as opposed to SFIOL .It can occur due to asymmetrical fixation of haptic,tight fixation and was less than a study done by Gonnerman [9].

ICIOL and SFIOL have statistically comparable results as far as post-operative BCVA is concerned but SFIOL has slightly higher percentage of patients with better visual acuity. ICIOL has slightly higher rate of complications most common was pupil ovalization which was harmless and others were also treatable. The implantation of a retropupillary iris-claw lens in the absence of sufficient capsular support is a good alternative, but SFIOL have better results in term of less complications. The easy implantation process with this SFIOL technique and short surgical time can be considered as the method of choice.

References

  1. Apple DJ, Mamalis N, Loftfield K, Googe JM, Novak LC, Kavka-Van Norman D et al. Complications of intraocular lenses. A historical and histopathological review. Surv Ophthalmol. 1984;29:1–54.
  2. Lundström M, Brege KG, Florén I, Lundh B, Stenevi U, Thorburn W.: Postoperative aphakia in modern cataract surgery: part 2: detailed analysis of the cause of aphakia and the visual outcome. J Cataract Refract Surg. 2004 Oct;30(10):2111-5.
  3. Alpar J-“Present state of management of aphakia. Future of spectacles and contact lenses”. Indian J Ophthalmol. 1989 Apr-Jun;37(2):54-7
  4. Dabezies OH Jr., Defects of vision through aphakic spectacle lenses. Ophthalmology. 1979 Mar;86(3):352-79.
  5. Ferris RL. Complications associated with aphakic contact lenses. Ophthalmology. 1979 Jun;86(6):1120-3.
  6. Por YM, Lavin MJ. Techniques of intraocular lens suspension in the absence of capsular/zonular support. Surv Ophthalmol 2005; 50:429–462
  7. Apple DJ, Brems RN, Park RB, Norman DK, Hansen SO, Tetz MR, Richards SC, Letchinger SD. Anterior chamber lenses. Part I: Complications and pathology and a review of designs. J Cataract Refract Surg. 1987 Mar; 13(2):157-74.
  8. Hara S, Borkenstein AF, Ehmer A, Auffarth GU. Retropupillary fixation of iris-claw intraocular lens versus transscleral suturing fixation for aphakic eyes without capsular support. J Refr act Surg 2011; 27:729–735.
  9. Gonnermann J, Klamann MK, Maier AK, Rjasanow J, Joussen AM, Bertelmann E, et al. Visual outcome and complications after posterior irisclawaphakic intraocular lens implantation. J Cataract Refract Surg 2012; 38:2139-43.

 

 

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