[Iris suture fixation of posterior chamber lenses. New perspectives for an old technique]

BACKGROUND

Intraocular approaches to correct aphakia in cases of inadequate capsular support include an anterior chamber intraocular lens, fixation of a posterior chamber lens to the sclera or iris by suturing or iris claw, respectively.

OBJECTIVES

This article reviews the indications and contraindications for iris fixation with sutures and gives an overview of surgical techniques, potential complications and outcomes.

METHODS

Based on a selective search of pertinent literature in PubMed the information from original articles and reviews are analyzed, summarized and discussed.

RESULTS

New surgical techniques have imparted an impetus to iris suture fixation with encouraging functional and morphological results offering a new promising alternative to the established options. Improved aspects arise for repositioning of a decentered intraocular lens and for a minimally invasive method for repair of late in-the-bag lens dislocation as seen more frequently by cataract surgeons.

CONCLUSION

A final evaluation of the proposed techniques is not possible because none has clearly emerged as the optimal method. Precise determination of small differences in visual outcome or complication rates requires a large prospective, randomized clinical trial.

Soluble opsin is present in human vitreous

The purpose of this research project was to evaluate if intravitreal opsins are present in human vitreous liquid which is, so far, unknown. Therefore a pilot study was conducted including 22 vitreal samples which were harvested at the beginning of a standard 23-gauge three-port pars plana vitrectomy for macular pucker, diabetic vitreous hemorrhage or vitreal floater removal as well as macular hole closure or vitreomacular traction relief from the central vitreous body. No adverse events or serious side effects occurred. All samples were immediately stabilized by human albumin and arginine and subsequently frozen. Short-wavelength cone opsin concentrations were analyzed by enzyme immune essay (EIA) with anti-proteolytic 400 mM arginine, pH 8.7, in the antigen capture phase. Intravitreal short-wavelength cone opsins were detected in all analyzed samples and respective concentrations ranged at levels of 157 pg/ml ± 73 pg/ml (MV ± SD; range: 27 pg/m-286 pg/ml). Eyes with MP/MH/DVH/VMT and VF exhibited intravitreal short-wavelength cone opsin concentrations of 189 pg/ml ± 68 pg/ml (range: 72 pg/ml-286 pg/ml)/96 pg/ml ± 39 pg/ml (range: 50 pg/ml-138 pg/ml)/126 pg/ml ± 88 pg/ml (range: 27 pg/ml-198 pg/ml)/224 pg/ml and 121 pg/ml. Further studies will quantify the intravitreal opsin pattern of all visual opsins and compare these concentrations between different vitreoretinal diseases. This in turn might offer a better pathophysiological understanding and new diagnostic and therapeutic strategies for various eye pathologies. As a hypothesis, soluble opsins might be a biomarker for retinal damage comparable to creatinine for kidney damage.

Optical Coherence Tomography (OCT) Device Independent Intraretinal Layer Segmentation

PURPOSE

To develop and test an algorithm to segment intraretinal layers irrespectively of the actual Optical Coherence Tomography (OCT) device used.

METHODS

The developed algorithm is based on the graph theory optimization. The algorithm's performance was evaluated against that of three expert graders for unsigned boundary position difference and thickness measurement of a retinal layer group in 50 and 41 B-scans, respectively. Reproducibility of the algorithm was tested in 30 C-scans of 10 healthy subjects each with the Spectralis and the Stratus OCT. Comparability between different devices was evaluated in 84 C-scans (volume or radial scans) obtained from 21 healthy subjects, two scans per subject with the Spectralis OCT, and one scan per subject each with the Stratus OCT and the RTVue-100 OCT. Each C-scan was segmented and the mean thickness for each retinal layer in sections of the early treatment of diabetic retinopathy study (ETDRS) grid was measured.

RESULTS

The algorithm was able to segment up to 11 intraretinal layers. Measurements with the algorithm were within the 95% confidence interval of a single grader and the difference was smaller than the interindividual difference between the expert graders themselves. The cross-device examination of ETDRS-grid related layer thicknesses highly agreed between the three OCT devices. The algorithm correctly segmented a C-scan of a patient with X-linked retinitis pigmentosa.

CONCLUSIONS

The segmentation software provides device-independent, reliable, and reproducible analysis of intraretinal layers, similar to what is obtained from expert graders.

TRANSLATIONAL RELEVANCE

Potential application of the software includes routine clinical practice and multicenter clinical trials.

[Implantation of intraocular lenses in the ciliary sulcus]

Implantation of an intraocular lens (IOL) into the ciliary sulcus is the second most common implantation site after the regular capsular bag (in the bag) placement of an IOL. Although mainly not primarily intended, it is very often used in both complicated cataract surgery and secondary implantation due to IOL dislocation or aphakia. In most cases stable positioning is possible, especially when using optic capture techniques. A variety of difficulties can occur with sulcus implantation depending on the anatomical and surgical conditions present at the time of implantation. The most anterior position of the sulcus lense has to be considered for calculation of the refractive power of the IOL.

Intraocular pressure measurements during flap preparation using 2 femtosecond lasers and 1 microkeratome in human donor eyes

PURPOSE

To evaluate and compare intraocular pressures (IOPs) during flap preparations performed using 2 femtosecond lasers and a mechanical microkeratome in human donor globes.

SETTING

University Medical Center Mainz, Mainz, and Euroeyes Clinic Stuttgart, Stuttgart, Germany.

DESIGN

Experimental study.

METHODS

A cannula was inserted through the optic nerve in human globes. The IOP was obtained continuously during flap preparation using the 60 kHz Intralase femtosecond laser, the 200 kHz Visumax femtosecond laser, or the Amadeus II microkeratome. For each experiment, a normal lamellar flap preparation (regular procedure) and a worst-case procedure (femtosecond laser interface was pressed against globe until docking maneuver was aborted) were performed.

RESULTS

During the regular procedure, the mean maximum IOP measured was 181.3 mm Hg (range 159.1 to 194.8 mm Hg) with the 60 kHz femtosecond laser, 77.6 mm Hg (range 58.1 to 100.3 mm Hg) with the 200 kHz femtosecond laser, and 198.1 mm Hg (range 162.8 to 299.6 mm Hg) with the microkeratome. During the worst-case procedure, the maximum measured IOP was 319.7 mm Hg (range 299.1 to 341.2 mm Hg) with the 60 kHz laser and 120.4 mm Hg (range 118.1 to 134.7 mm Hg) with the 200 kHz laser.

CONCLUSION

Maximum IOPs during corneal flap preparations in human enucleated eyes were lower during performance of a regular procedure and a worst-case procedure with the 200 kHz femtosecond laser than with the 60 kHz femtosecond laser and the mechanical microkeratome.

FINANCIAL DISCLOSURE

Dr. Sekundo is a member of the Scientific Advisory Board of Carl Zeiss Meditec AG, Jena, Germany. No author has a financial or proprietary interest in any material or method mentioned.

Evaluation of a posterior vitreous detachment: a comparison of biomicroscopy, B-scan ultrasonography and optical coherence tomography to surgical findings with chromodissection

PURPOSE

To find the most reliable and efficient noninvasive technique to clinically detect a posterior vitreous detachment.

METHODS

In a prospective study of 30 eyes in 30 patients with macular pucker or macular hole formation, the posterior vitreous cortex was examined 1 day prior to a scheduled vitrectomy. Three independent investigators classified the posterior vitreous cortex of each eye as 'attached' or 'detached' via slit-lamp biomicroscopy (BM), 10-MHz B-scan ultrasonography (I³ Innovative Imaging Inc.), and optical coherence tomography [OCT III Stratus(®) (Carl Zeiss Meditec Inc.) and RTVue-100 OCT (Optovue Corp.)]. These preoperative findings were then compared during a triamcinolone acetonide-assisted vitrectomy 1 day later.

RESULTS

Triamcinolone acetonide-assisted vitrectomy showed in 60% a posterior vitreous detachment and in 40% an attached posterior vitreous cortex. Preoperatively conducted B-scan ultrasonography and BM revealed the highest, correct evaluation of the posterior vitreous status. The prediction of the OCT was confirmed intraoperatively in 12.5%. In all other cases, the evaluation by OCT was not possible or was inadequate.

CONCLUSION

The prognostic most reliable but investigator-dependent methods to clinically detect whether the posterior vitreous cortex is detached are B-scan ultrasonography and BM. The objective technique of the high-resolution, two-dimensional time-domain OCT allows only in a few cases a clear differentiation of preretinal structures.

[Subluxation of a retropupillary iris claw lens after cyclophotocoagulation]

A 78-year-old patient underwent diode cyclophotocoagulation for end-stage pseudoexfoliation glaucoma after many surgical interventions on the only functional eye. On the first post-operative day the eye showed a mild flare and the intraocular eye pressure was normal. Nevertheless the patient complained of a severe decrease of visual acuity. A subluxation of a retropupillary iris claw intraocular lens within an atrophic area of the iris was found. During surgical revision the iris claw lens was successfully repositioned in the posterior chamber and an enclavation was performed at a different location avoiding atrophic areas of the iris. Fixation of an iris claw lens onto an atrophic iris structure should be avoided. Subluxation of an iris claw lens can occur following an uncomplicated diode laser cyclophotocoagulation operation.

The vitreomacular interface in retinal vein occlusion

PURPOSE

To evaluate the posterior vitreous adhesion status in patients with a history of central or branch retinal vein occlusion and to compare the results with the natural time-course of posterior vitreous detachment in healthy age-related controls.

METHODS

A retrospective chart review in terms of the posterior vitreous adhesion status was performed in 132 patients (133 eyes) with a history of a central (CRVO) or branch (BRVO) retinal vein occlusion. All patients underwent vitrectomy. Based on the operation reports, the vitreous adhesion status was classified as attached, partially detached or completely detached. The results were compared to the natural time-course of posterior vitreous detachment development in healthy age-related controls.

RESULTS

Eighty-one eyes met the inclusion and exclusion criteria. Fifty-two eyes (64%) had a history of CRVO and 29 eyes (36%) a history of BRVO, respectively. In the CRVO group, the posterior vitreous was attached in 47 eyes (90%) and completely detached in five eyes (10%). In the BRVO group, the posterior vitreous was attached in 27 eyes (93%), partially detached in 1 eye (3%) and completely detached in another eye (3%). A subdivision into age classes and a comparison with healthy age-related controls [data by Weber-Krause & Eckardt (1997) Ophthalmologe, 94, 619-623] showed in patients between 65 and 69 years of age an attached posterior vitreous cortex in 72% in healthy eyes, in 100% in CRVO (p = 0.109) and in 89% in BRVO (p = 0.440), in patients between 70 and 79 years of age an attached posterior vitreous cortex in 56% in healthy eyes, in 86% in CRVO (p = 0.010) and in 100% in BRVO (p = 0.038) and in patients between 80 and 89 years of age an attached posterior vitreous cortex in 43% in healthy eyes, in 100% in CRVO (p = 0.191) and in 67% in BRVO (p = 0.582) (Fisher's exact t-test).

CONCLUSION

In patients with a history of CRVO or BRVO, the posterior vitreous cortex stays attached more frequently in all age groups in comparison with the healthy age-related controls.

[Operative techniques for surgical treatment of primary and recurrent pterygia]

Surgical treatment of pterygia is indicated when there is a reduction of visual acuity secondary to the development of irregular astigmatism and an (impending) obscuration of the visual axis by the tumor. Poor cosmetic appearance and an insufficient corneal lubrication are more rare indications. The most popular surgical technique in this country appears to be a free conjunctival autograft which, depending on the priority of the surgeon, is combined with adjunctive antimetabolite therapy applied either in primary or recurrent cases. A simultaneous transplantation of conjunctival and limbal stem cell autografts is an excellent method to be considered particularly in cases of recurrent pterygia. In the case of non-existing healthy autologous tissue the resection bed can be covered by preserved amniotic membrane. A lamellar sectorial corneal graft might become necessary if there is a deep corneal defect. The well established technique of suturing the graft has been replaced by fibrin glue in some surgical centers.

Small incision corneal refractive surgery using the small incision lenticule extraction (SMILE) procedure for the correction of myopia and myopic astigmatism: results of a 6 month prospective study

AIM

This 6 month prospective multi-centre study evaluated the feasibility of performing myopic femtosecond lenticule extraction (FLEx) through a small incision using the small incision lenticule extraction (SMILE) procedure.

DESIGN

Prospective, non-randomised clinical trial. PARTICIPANTS; Ninety-one eyes of 48 patients with myopia with and without astigmatism completed the final 6 month follow-up. The patients' mean age was 35.3 years. Their preoperative mean spherical equivalent (SE) was −4.75±1.56 D.

METHODS

A refractive lenticule of intrastromal corneal tissue was cut utilising a prototype of the Carl Zeiss Meditec AG VisuMax femtosecond laser system. Simultaneously two opposite small ‘pocket’ incisions were created by the laser system. Thereafter, the lenticule was manually dissected with a spatula and removed through one of incisions using modified McPherson forceps.

MAIN OUTCOME MEASURES

Uncorrected visual acuity (UCVA) and best spectacle corrected visual acuity (BSCVA) after 6 months, objective and manifest refraction as well as slit-lamp examination, side effects and a questionnaire.

RESULTS

Six months postoperatively the mean SE was −0.01 D±0.49 D. Most treated eyes (95.6%) were within ±1.0 D, and 80.2% were within ±0.5 D of intended correction. Of the eyes treated, 83.5% had an UCVA of 1.0 (20/20) or better, 53% remained unchanged, 32.3% gained one line, 3.3% gained two lines of BSCVA, 8.8% lost one line and 1.1% lost ≥2 lines of BSCVA. When answering a standardised questionnaire, 93.3% of patients were satisfied with the results obtained and would undergo the procedure again.

CONCLUSION

SMILE is a promising new flapless minimally invasive refractive procedure to correct myopia.

Analysis of clinically suspected orbital cavernomas

BACKGROUND

Orbital cavernomas are low-flow vascular malformations that are the most common benign neoplasms of the orbit in adults, typically becoming symptomatic in the middle age.

METHODS

The medical records of six patients with clinically suspected orbital cavernomas receiving elective surgical excision were analysed concerning symptoms, physical findings, treatment results and visual outcome. The pathologic slides were evaluated, and additional immunohistochemical stains were done if necessary to obtain diagnosis.

RESULTS

Histologic evaluation revealed three of six cases not being cavernomas, although the clinical and macroscopic findings were consistent with orbital cavernomas. Two of them were haemorrhagic lymphangiomas, and one was a solitary fibrous tumour.

CONCLUSIONS

Haemorrhagic lymphangiomas and other vascular tumours may mimic orbital cavernomas regarding anamnesis, radiologic and intraoperative findings and gross examination. Therefore, exact histologic evaluation is necessary to get the correct diagnosis.