Optical Coherence Tomography of the Anterior Segment in Eyes with Phakic Refractive Lenses

Long-term In Vivo Stability of Posterior Chamber Phakic Intraocular Lens: Properties and Light Transmission Characteristics of Explants

PURPOSE

To evaluate the in vivo durability of the surface and optical properties of the implantable Collamer lens (ICL).

DESIGN

Retrospective case series.

METHODS

We included patients who developed cataracts after having undergone ICL implantation from March 2003 to May 2014 and underwent ICL explantation followed by cataract surgery from March 2017 to December 2019 at the Nagoya Eye Clinic. ICL explants were submitted to Chukyo Medical Co, Ltd (Nagoya City, Japan) for laboratory analysis using ultraviolet-visible light spectroscopy, light microscopy (LM), and scanning electron microscopy. Patients' demographic and clinical data were collected and reviewed.

RESULTS

Thirteen eyes from 10 patients were studied. The average age at ICL explantation was 50.5 ± 8.5 years (range, 34.5-66.3 years). The average length of ICL stay in the eye (from implantation to explantation) was 10.5 ± 2.7 years (range, 4.4-13.7 years). No opacification or coloring of the ICL explants was observed by LM. The ICL explants showed almost the same light transmittance as that of unused ICLs. Scanning electron microscopy revealed no irregularities at the surface of the center and periphery of the optic and haptic footplate. The positioning holes did not show any deposition.

CONCLUSION

The ICLs remained in-eye for >10 years without any deterioration in the surface and optical properties of the ICL, despite their contact with the ciliary body and iris tissues and the continuous interaction with the aqueous humor components. The present study shows long-term in vivo stability of the ICL.

Optical Coherence Tomography Reveals Sigmoidal Crystalline Lens Changes during Accommodation

This study aimed to quantify biometric modifications of the anterior segment (AS) during accommodation and to compare them against changes in both accommodative demand and response. Thirty adults, aged 18–25 years were rendered functionally emmetropic with contact lenses. AS optical coherence tomography (AS-OCT) images were captured along the 180° meridian (Visante, Zeiss Meditec, Jena, Germany) under stimulated accommodative demands (0–4 D). Images were analysed and lens thickness (LT) was measured, applying a refractive index correction of 1.00. Accommodative responses were also measured sequentially through a Badal optical system fitted to an autorefractor (Shin Nippon NVision-K 5001, Rexxam, Japan). Data were compared with Dubbelman schematic eye calculations. Significant changes occurred in LT, anterior chamber depth (ACD), lens centroid (i.e., ACD + LT/2), and AS length (ASL = ACD + LT) with accommodation (all p < 0.01). There was no significant change in CT with accommodation (p = 0.81). Measured CT, ACD, and lens centroid values were similar to Dubbelman modelled parameters, however AS-OCT overestimated LT and ASL. As expected, the accommodative response was less than the demand. Interestingly, up until approximately 1.5 D of response (2.0 D demand), the anterior crystalline lens surface appears to be the primary correlate. Beyond this point, the posterior lens surface moves posteriorly resulting in an over-all sigmoidal trajectory. he posterior crystalline lens surface demonstrates a sigmoidal response with increasing accommodative effort.

Anterior segment optical coherence tomography of long-term phakic angle-supported intraocular lenses

PURPOSE

To evaluate the long-term age-related anterior chamber changes by anterior segment optical coherence tomography (OCT) and the impact of such changes on the stability and behavior of angle-supported phakic intraocular lenses (IOLs).

DESIGN

A retrospective consecutive observational cohort study.

METHODS

A total of 23 eyes with high myopia implanted with an angle-supported phakic IOL between 1990 and 1996 at Vissum Corporación Oftalmológica de Alicante were included in the study. Patients were evaluated using OCT. Anterior chamber depth, anterior chamber width, crystalline lens rise, and the distance between phakic IOL and endothelium were measured.

RESULTS

Fifteen years after implantation, anterior chamber depth was 2.9 ± 0.3 mm, crystalline lens rise 748.18 ± 393.13 μm, and phakic IOL-endothelium distance 2.1 ± 0.30 mm. The predictive model showed that 30 years after implantation, endothelial cell count was less than 600 cells/mm(2) in patients with a preoperative spherical equivalent of -25 diopters (D). Twenty years after implantation, the safety zone of 1.5 mm between endothelium and the lens will not be respected in patients with a preoperative spherical equivalent of -20 D.

CONCLUSIONS

The findings of this study could have an important influence on the decision about the indication to implant angle-supported phakic IOLs in young patients with a long postoperative life expectancy, as age-related changes in the anatomy of the anterior segment may create a long-term hazard for the implanted eye.

Research on calculation of the IOL tilt and decentration based on surface fitting

The tilt and decentration of intraocular lens (IOL) result in defocussing, astigmatism, and wavefront aberration after operation. The objective is to give a method to estimate the tilt and decentration of IOL more accurately. Based on AS-OCT images of twelve eyes from eight cases with subluxation lens after operation, we fitted spherical equation to the data obtained from the images of the anterior and posterior surfaces of the IOL. By the established relationship between IOL tilt (decentration) and the scanned angle, at which a piece of AS-OCT image was taken by the instrument, the IOL tilt and decentration were calculated. IOL tilt angle and decentration of each subject were given. Moreover, the horizontal and vertical tilt was also obtained. Accordingly, the possible errors of IOL tilt and decentration existed in the method employed by AS-OCT instrument. Based on 6–12 pieces of AS-OCT images at different directions, the tilt angle and decentration values were shown, respectively. The method of the surface fitting to the IOL surface can accurately analyze the IOL's location, and six pieces of AS-OCT images at three pairs symmetrical directions are enough to get tilt angle and decentration value of IOL more precisely.

Rotation stability of the cachet angle-supported phakic intraocular lens

PURPOSE

To evaluate the rotational stability of an acrylic angle-supported phakic intraocular lens (PIOL) 12 months after implantation in myopic eyes.

METHODS

Patients with a history of moderate to high myopia underwent unilateral or bilateral implantation of an acrylic angle-supported PIOL (AcrySof Cachet; Alcon Laboratories, Inc., Fort Worth, TX). All were followed up for 12 months. IOL rotation was assessed using digital overlay of ocular photographs captured within 2 weeks of implantation and at postoperative month 12. The secondary outcomes of refractive power (spherical equivalent, refractive sphere, and cylinder) and uncorrected distance visual acuity (UDVA) and corrected distance visual acuity (CDVA) were assessed preoperatively and again at 3 months after implantation.

RESULTS

Fifty eyes of 28 patients with a mean age of 32 years were included in this retrospective cohort study. All underwent successful IOL implantation and follow-up. A mean 12-month rotation of 11° was observed (standard deviation: 15.1°, range: 0 to 60°). All preoperative measures (mean) of refractive power improved by 3 months postoperatively (spherical equivalent = -0.35 ± 0.79 diopters [D], spherical refraction = 0.04 ± 0.82 D, and cylindrical refraction = -0.77 ± 0.91 D). Two percent of eyes requiring additional laser adjustment by postoperative month 12, primarily due to corneal astigmatism.

CONCLUSION

The study findings suggest that AcrySof Cachet angle-supported PIOLs offer moderate 1-year rotational stability. Because this type of IOL also corrects myopia effectively, it appears to be a good treatment option for myopic eyes. However, the rotation that occurs makes it unsuitable for cylinder corrections.

Anterior segment variations after posterior chamber phakic intraocular lens implantation in myopic eyes

PURPOSE

To evaluate anterior segment variations after posterior chamber phakic intraocular lens (pIOL) implantation in myopic eyes.

SETTING

Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China.

DESIGN

Cohort study.

METHODS

Patients with high myopia were scheduled for nontoric Implantable Collamer Lens pIOL or toric Implantable Collamer Lens pIOL implantation. Anterior segment optical coherence tomography was performed to evaluate the anterior segment variations over time and the impact of physiologic accommodation and change in brightness after pIOL implantation. Slitlamp photography of the anterior segment was taken after pupil dilation to calculate pIOL rotation.

RESULTS

There was significantly improved visual acuity and refractive status after implantation of both pIOLs. Anterior segment axial variations had good stability 6 months postoperatively. However, nontoric pIOL rotation occurred in 1 eye 7 months postoperatively and rotation of the toric pIOL occurred in 2 eyes at 3 months and 6 months. Stimulations of -4.0 diopters (D) and -8.0 D led to significant changes in anterior chamber depth (ACD) based on the lens (ACD-lens), ACD after pIOL implantation, distance between the pIOL posterior surface and the lens anterior surface (pIOL-lens), and pupil diameter. Increasing ambient light brightness could reduce the ACD-lens and pIOL-lens.

CONCLUSIONS

Both pIOLs had good axial stability in myopic eyes 6 months postoperatively; however, rotational stability over time could not be determined. The physiologic adjustment and change in brightness could influence the anterior segment significantly in eyes with a pIOL.

The posterior chamber phakic refractive lens (PRL): a review

Implantation of phakic intraocular lenses (pIOLs) is a reversible refractive procedure, preserving the patient's accommodative function with minimal induction of higher order aberrations compared with corneal photoablative procedures. Despite this, as an intraocular procedure, it has potential risks such as cataracts, chronic uveitis, pupil ovalization, corneal endothelial cell loss, pigmentary dispersion syndrome, pupillary block glaucoma, astigmatism, or endophthalmitis. Currently, only two models of posterior chamber pIOLs are commercially available, the implantable collammer lens (STAAR Surgical Co.) and the phakic refractive lens (PRL; Zeiss Meditec). The number of published reports on the latter is very low, and some concerns still remain about its long-term safety. The present article reviews the published literature on the outcomes after PRL implantation in order to provide a general overview and evaluate its real potential as a surgical refractive option.

Changes in vaulting of myopic and toric implantable collamer lenses in different lighting conditions

PURPOSE

To evaluate the changes in vaulting of myopic and toric Implantable Collamer Lenses (ICLs) in different lighting conditions.

METHODS

Thirty-seven eyes of 37 patients implanted with a myopic ICL and 26 eyes of 26 patients implanted with a toric ICL were examined using Visante optical coherence tomography (OCT) in photopic (257 lux) and mesopic (2 lux) conditions. Pupil diameter and distance changes between the ICL and adjacent intraocular structures were measured.

RESULTS

The mean horizontal pupillary diameters in mesopic conditions were 5.3 ± 0.9 (SD) mm. In photopic conditions, a mean decrease of -1.8 ± 0.6 mm [95% confidence interval (95% CI) -2.0 to -1.7; p < 0.0001] was observed. The mean distances between the ICL and the crystalline lens in mesopic conditions were 0.33 ± 0.17 mm. In photopic conditions, a mean decrease of -0.04 ± 0.06 mm (95% CI -0.05 to -0.02; p < 0.0001) in the ICL-crystalline lens distance was found. There was a -0.02 ± 0.04 mm (95% CI -0.03 to -0.01; p = 0.0022) decrease in the anterior chamber depth and a 0.02 ± 0.06 mm (95% CI 0.002 to 0.032; p = 0.0275) increase in the distance between the cornea and the ICL. We found no difference in the change in vaulting between the two ICLs in different lighting conditions.

CONCLUSION

There is a decrease in the central vaulting of myopic and toric ICLs in photopic conditions. This is due to both posterior movement of the ICL and anterior protrusion of the crystalline lens.

Accommodative changes in anterior chamber depth in patients with high myopia

PURPOSE

To study the accommodative changes in the central anterior chamber depth (ACD) in patients with high myopia using anterior segment optical coherence tomography (AS-OCT).

SETTING

Cataract Surgery Department and Clinical & Functional Diagnostics Department, S. Fyodorov Eye Microsurgery Complex-Federal State Institution, Moscow, Russian Federation.

DESIGN

Prospective case-control study.

METHODS

The ACD measurements were obtained in the nonaccommodative state (baseline) and during accommodation using the Visante AS-OCT device.

RESULTS

Thirty-six myopic eyes (36 patients; mean age 27 years; mean spherical equivalent (SE) -12.52 diopters [D]) and 31 emmetropic eyes (31 subjects; mean age 26 years; mean SE -0.39 D) were examined. At baseline, the mean ACD in both groups was similar. During accommodation, the mean maximum changes in the ACD were significantly less pronounced in the myopia group (-0.14 mm ± 0.07 [SD]; range -0.03 to -0.29 mm) than in the emmetropia group (-0.22 ± 0.08 mm; range -0.04 to -0.35 mm) (P<.0001). Ten patients in the myopia group had a critically shallow anterior chamber (ACD <2.8 mm) in the state of accommodation.

CONCLUSIONS

Accommodative changes in the ACD were significantly less pronounced in eyes with high myopia than in emmetropic eyes. Still, the anterior chamber might become critically shallow during accommodation in some myopic eyes, and this should be taken into account when planning phakic intraocular lens implantation to correct high myopia.

FINANCIAL DISCLOSURE

No author has a financial or proprietary interest in any material or method mentioned.

Preliminary in vivo positional analysis of a posterior chamber phakic intraocular lens by optical coherence tomography and its correlation with clinical outcomes

Purpose

To analyze by spectral-domain optical coherence tomography the anatomical relationship of a specific type of posterior chamber phakic intraocular lens (pIOL) implanted in cases of high to moderate myopia with the adjacent intraocular structures and to correlate it with clinical outcomes.

Methods

Prospective observational case series including 18 eyes with high to moderate myopia (spherical equivalent between −5.88 and −15.75 D) of 9 patients (age range, 29–49 years) undergoing bilateral Phakic Refractive Lens (PRL, Zeiss) implantation. Postoperative visual acuity, refraction, contrast sensitivity (CS), and ocular higher order aberrations (HOA) were evaluated. Furthermore, the in vivo position of the PRL was analyzed by means of spectral domain optical coherence tomography (3D OCT-1000, Topcon). Central (CENV), temporal (TEMV) and nasal vault (NASV) were measured. Correlation of these anatomical parameters with clinical data was also investigated. Mean follow-up was 47 ± 25 months.

Results

A statistically significant visual and refractive improvement (p < 0.01) was found postoperatively. Mean postoperative CENV, NASV, and TEMV were 157.88 ± 69.93 μm, 168.29 ± 65.02 μm, and 188.59 ± 55.99 μm, respectively. Significant difference was found between NASV and TEMV (p = 0.01). No significant correlations were found between ocular aberrometric and anatomical parameters (p ≥ 0.12). CENV, NASV and TEMV correlated significantly with 6-cycles per degree (cpd) photopic CS as well as with 18-cpd low mesopic CS (r ≥ 0.57, p ≤ 0.04). Furthermore, NASV also correlated significantly with preoperative anterior chamber depth (r = −0.65, p = 0.01).

Conclusions

This posterior chamber pIOL shows a trend to nasal position, with potential impact on refractive and visual outcomes, particularly in eyes with deep anterior chambers.

Medium-term visual, refractive, and intraocular stability after implantation of a posterior chamber phakic intraocular lens to correct moderate to high myopia

PURPOSE

To evaluate the medium-term refractive and visual outcomes and the complications after implantation of a silicone posterior chamber phakic intraocular lens (PC pIOL) for moderate to high myopia.

SETTING

Oftalmar, Medimar International Hospital, Alicante, Spain.

DESIGN

Retrospective case series.

METHODS

Uncorrected (UDVA) and corrected (CDVA) distance visual acuities, refraction, and intraocular pressure were evaluated during a medium-term follow-up. Postoperative complications were also studied.

RESULTS

The study enrolled 35 eyes (mean preoperative spherical equivalent [SE] -10.25 diopters [D] ± 3.19 [SD]) of 20 patients with a mean age of 31.83 ± 8.87 years and a mean follow-up of 57.34 ± 9.24 months. The mean UDVA improved from 2.40 ± 0.20 logMAR preoperatively to 0.08 ± 0.13 logMAR at the last postoperative visit (P<.01). The mean CDVA improved from 0.11 ± 0.09 logMAR to 0.02 ± 0.09 logMAR, respectively (P<.01). The postoperative CDVA was 0.1 or better in 30 eyes (85.71%), with 22 eyes (62.86%) gaining lines of CDVA. The final efficacy index was 1.16 and the final safety index, 1.26. Regarding predictability, 34 eyes (97.14%) had an SE within ± 1.00 D and 33 eyes (94.28%) within ± 0.50 D. The complications were PC pIOL decentration (2 eyes, 5.71%), cortical lens opacification (1 eye, 2.86%), and retinal detachment (1 eye, 2.86%).

CONCLUSIONS

Implantation of a PC pIOL to correct moderate to high myopia was efficient and predictable in the medium term, with intraocular stability in most cases. New designs and criteria for PC pIOL size selection should be developed.

FINANCIAL DISCLOSURE

No author has a financial or proprietary interest in any material or method mentioned.

Ocular coherence tomography in lymphangiectasia

PURPOSE

To report the aid of ocular coherence tomography (OCT) in diagnosing conjunctival lymphangiectasia and correlate clinical and pathological findings.

METHODS

Single interventional case report. A 64-year-old man presented with a 2-year history of ocular discomfort, tearing, and a gradually enlarging lesion on the conjunctiva of his left eye.

RESULTS

Slit-lamp biomicroscopy revealed localized conjunctival swelling temporally in the left eye, with the lesion protruding between the upper and lower eyelids. Visante (Carl Zeiss-Meditec, Jena, Germany) OCT revealed clear fluid-filled spaces demarcated by septae within the elevated conjunctiva. The lesion was excised, and histopathology of the specimen showed features consistent with lymphangiectasia.

CONCLUSIONS

OCT, a valuable tool in imaging of the anterior segment, is also useful in evaluation of conjunctival pathology.

Intraocular stability of an angle-supported phakic intraocular lens with changes in pupil diameter

PURPOSE

To use anterior segment optical coherence tomography (AS-OCT) to evaluate the stability of a recently released angle-supported phakic intraocular lens (pIOL) in the anterior segment with changes in pupil diameter.

SETTING

Keratoconus Unit, Vissum Corporation, Alicante, Spain.

METHODS

In this observational cross-sectional study of consecutive eyes with moderate to high myopia, an AcrySof Cachet pIOL was implanted with the aim of minimizing the refractive error. An analysis of the position and stability of the pIOL before and after pharmacologic pupil dilation was performed 3 months postoperatively using the Visante AS-OCT system. A measurement protocol that included several anatomic parameters was developed and applied; the parameter values before and after dilation were compared.

RESULTS

Twenty eyes of 20 patients ranging in age from 24 to 48 years old were evaluated. The anterior chamber depth increased significantly with pupil dilation (mean change 0.06 mm +/- 0.08 [SD]) (P<.01). A significant change was also observed in the distance between the center of the cornea at the endothelial plane and the anterior surface of the pIOL (mean change 0.03 +/- 0.05 mm) (P = .01). The distances between the peripheral edges of the pIOL and the corneal endothelium and the distance between the crystalline lens and the pIOL did not change significantly (P>or=.14).

CONCLUSION

The angle-supported pIOL showed excellent intraocular behavior after pupil dilation, with no shortening of the distance between the pIOL and corneal endothelium at the center or peripheral edges of the pIOL.

Value of optical coherence tomography for anterior segment surgery

Anterior segment optical coherence tomography (AS-OCT) is an important new noncontact imaging technology that uses a 1310 nm super luminescent diode. It can be used to assess anterior chamber biometry, corneal thickness, lens thickness, and angle configuration; to visualize pathological processes; to evaluate postsurgical anatomy and posttraumatic eyes; and to image phakic intraocular lenses and intracorneal ring segments. Because it is a noncontact technique, it can also be used intraoperatively, which could be useful during trabeculectomy and after deep anterior lamellar keratoplasty to detect abnormalities in the cornea and interface. A disadvantage of AS-OCT is its inability to penetrate the iris pigment epithelium, which makes it impossible to evaluate the structures behind the iris. The most frequently used devices are time-domain AS-OCT, but new Fourier-domain OCT devices, which have faster image acquisition and higher resolution, are currently under investigation.

FINANCIAL DISCLOSURE

No author has a financial or proprietary interest in any material or method mentioned.

Vaulting of myopic and toric Implantable Collamer Lenses during accommodation measured with Visante optical coherence tomography

PURPOSE

To study changes in vaulting of myopic and toric Implantable Collamer Lenses (ICLs) version 4 during accommodation with Visante optical coherence tomography (OCT), and analyze the relationship between vaulting and anterior subcapsular opacification.

DESIGN

Cross-sectional study.

PARTICIPANTS

Seventy-seven eyes of 77 myopic patients were examined after implantation with an ICL (48 myopic, 29 toric). The median follow-up time was 63 months (range, 10-84).

METHODS

The distance between the posterior ICL surface and the anterior surface of the crystalline lens was measured in the nonaccommodative state and during accommodation with Visante OCT. The lenses were examined for opacification using slit-lamp microscopy.

MAIN OUTCOME MEASURES

The distance between the ICL and the anterior surface of the crystalline lens.

RESULTS

At baseline, the mean distance between the ICL and the crystalline lens was 0.31+/-0.19 mm and during accommodation 0.31+/-0.26 mm; the difference did not reach significance (P = 0.77). The distance at baseline was significantly (P = 0.01) less in older patients and significantly (P = 0.04) greater in patients with a toric ICL. Contact was observed at baseline or during accommodation in 12 eyes; there was a significantly lower incidence of contact in eyes implanted with a toric ICL (P = 0.03). Anterior subcapsular opacification developed in 10 eyes, in 5 of these the ICL touched the crystalline lens.

CONCLUSIONS

Anterior subcapsular opacification developed in 13.0% of eyes. We found no difference in vaulting of the ICL at baseline and during accommodation. There was contact between the ICL and the crystalline lens in 15.6% of the eyes. The association between anterior subcapsular opacification and contact was significant (P = 0.004).

[Anterior segment examination of a post-traumatic, multioperated eye with Visante OCT. A case report]

INTRODUCTION

The optical coherence tomography (OCT) exploration of the retina has become almost routine and its semiology is well known. In contrast, the OCT exploration of the anterior segment is still in its preliminary stages.

CASE REPORT

We report the clinical aspects and the OCT Visante((R)) imaging of the anterior segment in a 35-year-old patient, victim of a penetrating injury of the left eye who required several operations including iterative vitrectomy for recurrent retinal detachment caused by proliferative vitreoretinopathy, use of high-density silicone oil, cataract surgery with in-the-bag intraocular lens implantation, and YAG-laser capsulotomy.

DISCUSSION

The correlation between slit lamp examination and OCT imaging is very good. We debate in a nonexhaustive manner the different imaging possibilities of this new technology and discuss its advantages in the postsurgical exam and its value in medicolegal expert reports as well as in comparison with pictures acquired by OCT normally used to image the posterior segment.

CONCLUSION

Future research will undoubtedly confirm the contribution of this new tool to explore the anterior segment in numerous contexts, including ophthalmological trauma medicine.

Late-onset decentration of iris-fixated phakic intraocular lenses: a case series

PURPOSE

To investigate late-onset downward decentration of iris-fixated phakic intraocular lenses (pIOL) resulting from progressive shifting of the haptics through the iris and its influence on the position of the pIOL and the amount of enclavated iris tissue.

DESIGN

Institutional, prospective, observational case series.

METHODS

Six patients (9 eyes) from among 368 eyes had 1 shifted haptic during long-term follow-up. Anterior segment optical coherence tomography (AS-OCT) was used to measure the distance between the edges of the pIOL and the corneal endothelium. Slit-lamp photography imaged the pIOL after implantation and after decentration. The images were analyzed to determine decentration and amount of iris tissue at the enclavation sites.

RESULTS

Shifting of the haptics occurred in 2.4% and was discovered at a mean follow-up of 4.8 years (range, 3 to 7 years). Mean downward decentration was 0.28 +/- 0.15 mm. Mean edge-distances on the nasal, temporal, superior, and inferior side were 1.71 +/- 0.30 mm, 1.86 +/- 0.31 mm, 1.86 +/- 0.31 mm, and 1.58 +/- 0.34 mm, respectively. Mean enclavated iris tissue on the nasal and temporal side was smaller after decentration when compared with that directly after surgery (P = .033 and P = .017, respectively). Shifting of the haptics did not result in a decreased uncorrected and best-corrected visual acuity.

CONCLUSIONS

Late-onset downward decentration resulting from progressive shifting of the haptics occurred in 2.4% and was associated with a decrease in enclavated iris tissue. AS-OCT showed a mean distance between the edge of the pIOL and the endothelium greater than the advised safety distance of 1.5 mm.

Objective vs subjective vault measurement after myopic implantable collamer lens implantation

PURPOSE

To evaluate the relationship between subjective measurements of vault and objective values measured with Visante optical coherence tomography (OCT) in eyes receiving an implantable contact lens (ICL) for myopia correction.

DESIGN

Observational cross-sectional study.

METHODS

SETTING

Fernández-Vega Ophthalmological Institute, Oviedo, Spain.

PATIENTS

Four hundred and fifty-two eyes from 246 patients were elected to be implanted with a Visian ICL V4 (STAAR Surgical Inc, Monrovia, California, USA).

OBSERVATION PROCEDURES

Subjective and objective measurements of vault after implantation of ICL.

MAIN OUTCOME MEASURES

Subjective vault classified in 5 levels assessed using an optical section during slit-lamp examination. Objective vault was measured with Visante OCT (Carl Zeiss Meditec Inc, Dublin, California, USA).

RESULTS

Average values of objective and subjective vault were 414 +/- 228 microm and 2.1 +/- 1.0, respectively and both parameters were highly correlated (r = 0.82; P < .001). Differences in average objective vault were statistically significant among the 5 groups of subjective vault (P < .001). Subjective vault 0 corresponded to a mean OCT value of 62 +/- 49 microm with 99% confidence interval (CI) [38; 86] microm; eyes with vault 1 to 203 +/- 93 microm with 99% CI [176; 230] microm; eyes with vault 2 to 402 +/- 131 microm with 99% CI [378; 425] microm; eyes with vault 3 to 594 +/- 146 microm, 99% CI [554; 633] microm; and vault 4 to 794 +/- 182 microm with 99% CI [713; 875] microm.

CONCLUSIONS

Subjective and objective values of vault are highly correlated. In 99% of cases within the CI, objective values for eyes subjectively classified within a certain level vary within a narrow interval (+/-25 to 80 microm) around the mean value, and this interval is characteristic of each subjective level.

Influence of anterior chamber morphometrics on endothelial cell changes after phakic intraocular lens implantation

PURPOSE

To analyze the position of iris-fixated phakic intraocular lenses (pIOLs) using anterior segment optical coherence tomography (AS-OCT) and evaluate the effect of anterior chamber morphometrics on endothelial cell changes.

SETTING

Department of Ophthalmology, Academic Hospital Maastricht, The Netherlands.

METHODS

In this cross-sectional study, AS-OCT was used to measure the distances from the center and the edges of the pIOL to the corneal endothelium in 242 eyes with various models of myopic pIOLs. Endothelial cell measurements were performed preoperatively and at each follow-up examination.

RESULTS

The mean follow-up was 34.1 months+/-24.7 (SD) (range 3 months to 7 years). The mean distance between the edge of the pIOL and the endothelium was 1.37+/-0.22 mm. Although this distance was smaller than the safety value of 1.50 mm in 68.6% of the eyes, no eye developed corneal decompensation. There was a significant endothelial cell density (ECD) loss of 1.28%+/-8.46%, 3.25%+/-8.24%, and 5.02%+/-10.40% at 2 years, 5 years, and 7 years, respectively. Linear mixed-model analysis predicted a yearly ECD loss of 0.98% for a mean edge distance of 1.37 mm, 0.15% for an edge distance of 1.59 mm (mean plus 1 SD), and 1.80% for an edge distance of 1.15 mm (mean minus 1 SD).

CONCLUSIONS

A shorter distance between the edge of the pIOL and the endothelium was significantly associated with higher ECD loss. For safety reasons, the postoperative examination should include long-term evaluation of the anterior chamber morphometrics in addition to ECD counts.