Intraocular Pressure in Myopic Patients After Worst-Fechner Anterior Chamber Phakic Intraocular Lens Implantation

Diagnostic Techniques to Increase the Safety of Phakic Intraocular Lenses

Preoperative and postoperative diagnostics play an important role in ensuring the safety of patients with phakic intraocular lenses (pIOLs). The risk of endothelial cell loss can be addressed by regularly measuring the endothelial cell density using specular microscopy and considering the endothelial cell loss rate and the endothelial reserve in accordance with the patient's age when deciding whether to explant a pIOL. The anterior chamber morphometrics, including the anterior chamber depth and the distance between the pIOL and the endothelium, measured using Scheimpflug tomography and anterior segment optical coherence tomography (AS-OCT), can help to assess the risk of the endothelial cell loss. In patients undergoing posterior chamber pIOL implantation, accurate prediction of the vault and its postoperative measurements using AS-OCT or Scheimpflug tomography are important when assessing the risk of anterior subcapsular cataract and secondary glaucoma. Novel approaches based on ultrasound biomicroscopy and AS-OCT have been proposed to increase the vault prediction accuracy and to identify eyes in which prediction errors are more likely. Careful patient selection and regular postoperative follow-up visits can reduce the complication risk and enable early intervention if a complication occurs.

Retinal detachment surgery in eyes with iris-fixated phakic intraocular lenses: Short-term clinical results

PURPOSE

To evaluate the safety of retinal detachment (RD) surgery in eyes with iris-fixated phakic intraocular lenses (pIOLs) and the efficacy of the pIOLs in correcting myopia after RD surgery.

SETTING

Single university-based tertiary referral center.

DESIGN

Retrospective case series.

METHODS

Eyes that had RD surgery (RD group) and healthy fellow eyes (control group) of the same patients were evaluated over 1 year. Surgical success, corrected distance visual acuity (CDVA), anterior chamber depth (ACD), endothelial cell density (ECD), and intraocular pressure (IOP) were assessed preoperatively and postoperatively to evaluate the safety of the surgery. The uncorrected distance visual acuity (UDVA) and spherical equivalent were assessed to evaluate the efficacy of the pIOL after RD surgery.

RESULTS

Twenty-two eyes of 11 patients were assessed. Reattachment was achieved in 10 eyes (90.9%) with the first intervention. After 1 year, the mean UDVA was 0.16 ± 0.15 logMAR (SD) in the RD group and 0.09 ± 0.12 logMAR in the control group (P=.332). The mean CDVA was 0.03 ± 0.07 logMAR in the RD group. The differences in the mean postoperative ACD and ECD between the 2 groups were not significant (P=.088 and P=.270, respectively). The mean IOP in the RD group was significantly higher than in the control group up to 1 month postoperatively; thereafter, the difference was not significant.

CONCLUSIONS

Preservation of a pIOL during RD surgery did not diminish the safety of the surgery. The efficacy of the pIOL in correcting myopia was not markedly compromised.

[Long-term changes in pupil size after implantation of an Artisan phakic intraocular lens for correction of high myopia]

PURPOSE

To evaluate the long-term changes in pupil size after implantation of an Artisan phakic intraocular lens for correction of high myopia.

PATIENTS AND METHODS

Fourteen myopic eyes of seven patients were included in the study. Pupil size was measured under photopic conditions, under scotopic conditions after 10 min of dark adaptation, and after topical medical mydriasis. The pupil size was measured using the eye image of the OPD scan (Nidek).

RESULTS

The mean follow-up was 46 months after surgery. The mean photopic pupil diameter was 2.94+/-0.33 mm (range, 2.54-3.6 mm). The diameter of the scotopic pupil remained less than 6.0 mm in all patients (4.68+/-0.59 mm, with maximal pupil diameter of 5.67 mm). The mean pupil diameter after pharmacological dilation was also reduced (5.39+/-1.08 mm; range, 4.19-7.59 mm), with pupil dilation more than 7 mm in only one patient.

CONCLUSION

The iris-fixated intraocular lens mechanically limited pupil dilation in our patients. The long-term reduction in pupil size after Artisan phakic intraocular lens implantation may contribute to the maintenance of the quality of vision in scotopic conditions.

Phakic Intraocular Lenses

An analytical review of the data available in the field of phakic intraocular lens implantation was conducted. Particular attention was paid to the more critical issues of intraocular lens sizing and safety guidelines. A comprehensive, competitive analysis of different implantation sites, intraocular lens model designs, and safety guidelines has been included. Specialized biometry techniques, such as very high frequency ultrasound and Scheimpflug imaging, have been reviewed, and a critical review of commercial claims regarding intraocular lens technologies has been included. Clinical studies of phakic intraocular lenses demonstrate increasing promise for the correction of refractive errors not amenable to mainstream excimer laser refractive surgery. The main issues currently revolve around adequate lens design (VHF ultrasound study suggests that custom-design and sizing may be the most effective and safest approach for every phakic IOL model), because these devices will be required to remain physiologically inert and anatomically compatible with internal ocular structures and relations for several decades. The possibility of safe removing or exchanging the IOL should remain a feasible option over time. It is of utmost importance that we continue to critically evaluate current encouraging short-term outcomes, which are being extrapolated to the longer term by ongoing high resolution imaging and monitoring of the anatomical and functional relations of implanted phakic IOLs.