Bilateral intraocular lens subluxation secondary to haptic angulation

Impact of intraocular lens characteristics on intraocular lens dislocation after cataract surgery

Background

To assess the influence of intraocular lens (IOL) characteristics on IOL dislocations after cataract surgery.

Methods

Patients who underwent cataract surgery at the Department of Ophthalmology Graz, Austria, between 1996 and 2017 were included and medical records were reviewed. Cox proportional-hazard regression models were used to assess the influence of IOL characteristics on IOL dislocation.

Results

From 68 199 eyes out of 46 632 patients (60.2% women, mean age: 73.71 SD±10.82 years), 111 (0.16%) had an in-the-bag (ITB) disloaction and 35 (0.05%) had an out-of-the-bag (OTB) dislocation. The HRs adjusted for predisposing factors significantly associated with a higher risk for an ITB dislocation were 2.35 (95% CI, 1.45 to 3.8) for hydrophilic IOLs, 2.01 for quadripode IOLs (95% CI, 1.04 to 3.86) and 1.61 (95% CI, 1.04 to 2.48) for haptic angulation. A lower risk was observed for three-piece IOLs (HR=0.58, 95% CI, 0.34 to 0.98) and larger overall IOL diameter (HR=0.79, 95% CI, 0.66 to 0.95). For an OTB dislocation, the HR associated with a higher risk was 18.81 (95% CI, 5.84 to 60.58) for silicone IOLs and 2.12 (95% CI, 0.62 to 7.29) for hydrophilic IOLs. Larger overall IOL diameter (HR 0.40, 95% CI; 0.25 to 0.63) showed a lower risk.

Conclusion

Hydrophilic IOLs, quadripode IOLs and haptic angulation were associated with a higher risk for an ITB dislocation, whereas three-piece IOLs and a larger overall diameter were associated with a lower risk. Risk factors for OTB dislocation were silicone IOLs, hydrophilic IOLs and a smaller overall IOL diameter.

[Early in-the-bag spontaneous intraocular lens dislocation of hydrophilic acryl single piece lenses following uncomplicated phacoemulsification]

BACKGROUND

As techniques for cataract surgery have evolved, spontaneous intraocular lens (IOL) dislocation in patients with no ocular pathology arises less frequently. We present seven consecutive cases of uncomplicated cataract surgery with early in-the-bag spontaneous intraocular lens dislocation for which the same type of hydrophilic single piece lens was used.

MATERIAL AND METHODS

A retrospective analysis was conducted on seven cases involving patients with IOL dislocation who underwent uncomplicated cataract surgery within a period of 4 months (October 2010 to January 2011) using the same type of single piece IOL. The median age of the 7 patients was 73 years and IOL repositioning was performed after an average of 10 weeks.

RESULTS

Sulcus repositioning could be carried out in only five of the seven patients and IOL repositioning within the capsule was achieved in one patient. A second patient exhibited IOL dislocation after yttrium aluminium garnet (YAG) laser capsulotomy. Explantation of the IOL and sulcus implantation of another IOL type (Acrysof MA50 MB) was necessary for a third patient. A fourth case presented an angled IOL haptic and dislocation of the IOL in the sulcus position.

DISCUSSION

Even after uncomplicated cataract surgery, spontaneous in-the-bag IOL dislocation in patients with no ocular pathology may occur due to a hydrophilic lens material which induces stronger anterior capsular phimosis (ACP) in comparison to alternative materials. In combination with a thin lens design this may result in angled IOL haptics and IOL dislocation.

CONCLUSIONS

Careful selection of suitable lens design and material according to individual predisposing factors is necessary. This retrospective case study demonstrates that the combination of hydrophilic lens material and a thin lens design may result in early spontaneous IOL dislocation. Furthermore, as established in one case, YAG laser capsulotomy may induce IOL dislocation if the lens design cannot withstand capsular fibrosis.

[Subluxation of hydrophilic acrylate intraocular lenses due to massive capsular fibrosis]

BACKGROUND

Compared with other biomaterials, hydrophilic acrylate provides better uveal biocompatibility, lower adhesion rates of bacteria and silicone oil, and less glare. Because of reduced capsular biocompatibility, increased fibrosis may initiate dislocation of the intraocular lens (IOL).

PATIENTS

In six eyes of four patients, enhanced fibroses led to IOL dislocation, leading to an IOL exchange an average of 40 weeks after implantation of the same hydrophilic acrylate lens type.

DISCUSSION

Predisposing factors were found in 90% of all reported cases of IOL dislocation in the literature, but not in the cases described here. The lens type that was implanted was unable to adapt to the massive fibrosis induced by its hydrophilic biomaterial.

CONCLUSIONS

The pattern of lens opacification should receive attention when one is choosing an IOL type. Eyes showing pseudoexfoliation syndrome as well as post-uveitis eyes might require a hydrophilic IOL for less cellular reaction, whereas a posterior subcapsular cataract might need a hydrophobic IOL to prevent a massive capsular fibrosis. In the case of increased capsular contraction, unreflected YAG laser capsulotomy may result in IOL subluxation when the lens design cannot handle capsule shrinkage, as demonstrated here.