Image quality in polypseudophakia for extremely short eyes

Treatment of Nanophthalmos Cataracts: Surgery and Complications

PURPOSE

Cataract surgery in patients with nanophthalmos is complicated for ophthalmologists to perform. Due to the unique ocular anatomy, there is a high incidence of complex complications such as angle-closure glaucoma, fluid misdirection syndrome, and uveal effusion syndrome (UES) in the perioperative period of cataract surgery. This article will discuss the management options for cataract surgery in nanophthalmic eyes and complications.

METHODS

This review is searched through PubMed, focusing on articles published in the past 20 years. Articles were reviewed on the anatomical structure of nanophthalmic cataracts, the pathogenesis of complications, the selection of intraocular lenses, and surgical methods.

CONCLUSION

There is a strong correlation between abnormal ocular anatomy and complications in patients with nanophthalmos. Clinicians must not only select the appropriate intraocular lens formula based on the depth of the anterior chamber but also formulate personalized surgical methods based on its unique anatomical structure to avoid complications.

Analysis of the Optical Quality of Spherical and Aspheric Intraocular Lenses in Simulated Nanophthalmic Eyes

PURPOSE

To analyze the optical performance of different implant strategies in simulated nanophthalmic eyes.

METHODS

An optical design software was used. Analysis included eye models that required 30.00, 45.00, and 60.00 diopters (D) intraocular lenses (IOLs) to achieve emmetropia. Spherical and aspheric IOLs were designed. They were tested either with a single implant setting S or by splitting the power into two lenses. Setting P1 had an even split of the power between the lenses and setting P2 had an uneven power split with one-third of the power in the anterior lens and two-thirds in the posterior IOL. The area under the modulation transfer function (MTF) curve was calculated and spherical aberration was recorded in each setting.

RESULTS

Setting S had the worst optical performance in the spherical group and the best performance in the aspheric group. A statistically significant difference was found between setting S and the piggyback options (settings P1 and P2) in all analyzed variables for the spherical and aspheric groups for the 45.00 and 60.00 D IOL requirement. No statistically significant difference was found between the piggyback settings.

CONCLUSIONS

Single aspheric IOLs had better optical performance than piggybacking lower-power aspheric IOLs. In the spherical lenses group, the results were the opposite, with the piggyback options having higher optical quality than the single IOL. MTF shows that single aspheric lenses provide the highest contrast sensitivity among all of the analyzed settings.

Combining primary and piggyback intraocular lenses to treat extreme myopic astigmatism in stable keratoconus following cataract surgery

The majority of those with keratoconus can maximise visual acuity with spectacle or contact lens correction as they age; however, as subjects enter their sixties, cataracts may supervene and contact lens tolerance diminishes with consequent reduction in visual acuity. Following cataract extraction, the complex refractive error associated with keratoconus may not be readily corrected by an intraocular lens alone. This report highlights the planned implantation of a primary posterior chamber toric intraocular lens with a secondary piggyback, sulcus-based, intraocular lens in advanced but stable keratoconus with extreme myopic astigmatism and cataract.

Polypseudophakia for cataract surgery: 10-year follow-up on safety and stability of two poly-methyl-methacrylate (PMMA) intraocular lenses within the capsular bag

PURPOSE

To report the long-term follow-up (more than 10 years) of three patients who have undergone polypseudophakia phacoemulsification cataract surgery.

METHODS

A case series of three patients and four procedures. Two poly-methyl-methacrylate (PMMA) intraocular lenses (IOLs) were placed within the capsular bag (P359UV, Storz, Tuttlingen, Germany). No complications occurred peri-operatively. A full ophthalmological examination was performed at 10-year follow-up, looking for decentration, tilt, and complications of interlenticular opacification (ILO) between the IOLs.

RESULTS

Inferior ILO with Elschnig pearls was observed in only one case, and was likely to be visually insignificant. No ILO was observed in the other three eyes. In one patient, the piggyback IOL had been displaced 1-2 mm nasally, but there was no tilt of the IOLs, with the haptics remaining well aligned. There was no displacement or tilt of the piggyback IOL in the other three cases. Corneal endothelial cell count (SP-2000P, Topcon, Tokyo, Japan) was above 1000 cell/mm(2) in all cases.

CONCLUSIONS

With the introduction of foldable IOLs, the piggyback IOL is usually placed in the sulcus, but we have shown good long-term stability and minimal complications of dual PMMA IOLs placed within the bag.

Análise da fórmula SRK/T no cálculo de lente intra-ocular em cães portadores de catarata

Foram utilizados 20 cães de raças e idades variadas, machos e fêmeas, portadores de catarata e não diabéticos, os quais foram submetidos ao exame oftálmico. Posteriormente, realizaram-se mensurações oculares empregando-se um ecobiômetro ultra-sônico (ultra-sonografia modo-A) para o cálculo do poder dióptrico da lente intra-ocular por meio da fórmula SRK/T. O comprimento axial médio foi de 19,94±1,12mm. Todos os animais foram submetidos à facoemulsificação extracapsular. A lente calculada foi implantada no transoperatório da cirurgia de catarata, obtendo-se média de 37,33±3,05D. A avaliação pós-cirúrgica do erro refracional aos 60 dias de pós-operatório, pela retinoscopia, com a utilização da esquiascopia, foi de 5,57±1,59D. A fórmula SRK/T não ofereceu bons resultados.

Refraktive Langzeitergebnisse nach Huckepackimplantation

BACKGROUND

Piggyback lens implantation is an alternative to exchange of the original intraocular lens (IOL) to treat high anisometropia in pseudophakic eyes. We present our results.

PATIENTS AND METHOD

A second IOL (piggyback) was implanted in 27 patients from 2000 to 2006. Nineteen patients were clinically investigated late postoperatively, and data for the other eight patients were evaluated from the patients' files.

RESULTS

The patients were 65+/-9 years old. Follow-up time was 38+/-25 months. The mean preoperative spherical equivalent (SE) in the myopic eyes was -7.86+/-3.82 D and in the hyperopic eyes was 1.64+/-0.74 D. After surgery, the mean SE in the myopic eyes was -1.77+/-1.82 D and in the hyperopic eyes was -0.09+/-0.51 D. Postoperative anisometropia was reduced from 4.64+/-3.3 D. to 0.9+/-0.82 D.

CONCLUSION

Piggyback lens implantation is a safe and effective surgical procedure and is less traumatic than exchange of the original IOL.

Primary piggyback implantation using the ReSTOR intraocular lens: Case series

PURPOSE

To assess the postoperative outcomes of piggyback implantation using the AcrySof ReSTOR intraocular lens (IOL) (model SA60D3, Alcon Surgical Laboratories).

SETTING

Hospital Oftalmológico de Brasília, Brasília, Brazil.

METHODS

Thirteen eyes of 7 patients who had phacoemulsification with piggyback IOL implantation were analyzed prospectively. In all cases, a ReSTOR IOL was implanted in the capsular bag and a second silicone IOL was implanted in the ciliary sulcus. Information collected included uncorrected visual acuity (UCVA) at near and distance, best corrected visual acuity (BCVA), and spherical equivalent (SE) before and after surgery.

RESULTS

The patients were followed for 12 months. The mean distance UCVA was 0.25 (20/80) preoperatively and 0.88 (20/23) at the last follow-up (1 year), which was significantly better than before surgery (P<.05). The mean SE was +4.25 diopters (D) +/- 1.5 (SD) preoperatively and +0.15 +/- 0.44 D (range -0.50 to +0.75 D) at 1 year, which was significantly better than preoperatively (P<.05). No patient lost lines of BCVA after surgery. At the last follow-up, all eyes had a near UCVA of J1 and none required spectacles for near or distance vision.

CONCLUSION

Piggyback implantation using the ReSTOR IOL appeared to be a safe and efficient procedure providing high-quality visual acuity for near and distance vision in selected patients.

Cataract surgery in the small adult eye

Microphthalmos is a rare condition that is often associated with several other ocular abnormalities. Given the considerable differences between microphthalmic and anatomically normal eyes, cataract surgery is technically demanding in these patients, and special attention must be given to adequate preoperative planning of these procedures. Furthermore, the unique nature of these surgeries creates a particular subset of intraoperative and postoperative complications. However, with the advent of piggyback intraocular lens placement, the visual outcomes of cataract surgery in small adult eyes have improved considerably over the past 20 years. This review discusses the nature of the microphthalmic eye, and addresses proper pre-, intra-, and postoperative care of the microphthalmic patient.

Primary polypseudophakia for cataract surgery in hypermetropic eyes: refractive results and long term stability of the implants within the capsular bag

AIM

To determine the long term visual and refractive results, and stability and complications of primary polypseudophakia using poly(methylmethacrylate) (PMMA) intraocular lenses (IOLs) for cataract surgery in hypermetropic eyes.

METHODS

Prospective study of 15 short or hypermetropic eyes undergoing phacoemulsification with primary polypseudophakia with two PMMA IOLs implanted within the capsular bag.

RESULTS

The spherical equivalent was reduced from a mean +4.87 (SD 3.00) dioptres (D) to -0.12 (1.40 D), and the deviation from the intended refraction was +0.005 (1.30) D, 23.6 (12.36) months post-implantation. The deviation from intended refraction was not statistically significant (p = 0.989; paired t test). Postoperative best corrected visual acuity (BCVA) was 6/12 or better in all eyes without macular or optic nerve co-morbidity. Interlenticular opacification (ILO) in the form of peripheral Elschnig pearls was seen in four (26.67%) eyes. A new type of ILO in the form of usually pigmented deposits in the central interface developed in five (33.33%) eyes and resulted in the appearance of Newton's rings in three. None of the eyes with ILO had any loss of BCVA or hyperopic shift. Six (40%) eyes were within 1 D from the intended refraction and 14 (93.33%) within 2 D. There was no statistically significant difference in the accuracy of the two intraocular lens calculation formulas used (SRK II and SRK/T).

CONCLUSION

Peripheral Elschnig pearl-type ILO can occur as a late complication of primary in the bag implantation of two PMMA IOLs. A new type of ILO is described. Both types of ILO have not to date resulted in deterioration of visual acuity in our cohort. Use of appropriate biometry techniques and IOL calculation formulas may yield more accurate refractive results.

Piggyback implantation using the AMO array multifocal intraocular lens

Piggyback intraocular lens (IOL) implantation allows refractive correction in cases in which the IOL power requirement exceeds that of the available lenses. By combining a piggyback technique with the use of a multifocal IOL, one can obtain the optical advantages of both, achieving high-quality visual acuity for distance and near vision and reducing the optical aberrations of extremely high-powered single IOLs. We report 5 hyperopic patients (6 eyes) who had phacoemulsification and in-the-bag implantation of 2 foldable IOLs in the bag, a silicone multifocal IOL placed in front of a silicone monofocal IOL. Good results were obtained in near and distance uncorrected visual acuities, and patient satisfaction was excellent in all cases. However, in 2 cases, the anteriorly placed IOL was exchanged because of incorrect power calculation. Piggyback IOL implantation with a multifocal lens appears to be a safe, efficient procedure and a good refractive solution.

Interlenticular opacification in piggyback AcrySof intraocular lenses: explantation technique and laboratory investigations

BACKGROUND/AIMS

Interlenticular opacification (ILO) is a recognised complication of piggyback intraocular lenses (IOLs). The aetiology, histopathology, and treatment are not clearly defined, however.

METHODS

Two pairs of AcrySof IOLs were explanted from a patient with bilateral ILO. The explantation technique and surgical challenges of IOL exchanges are described. The explanted IOL complexes and a sample of the anterior capsule were examined by phase, polarising, and immunofluorescence microscopy.

RESULTS

A 50 year old man developed ILO bilaterally after piggyback AcrySof IOL implantation. A central contact zone was surrounded by a homogeneous paracentral opacity possibly consisting of extracellular matrix previously laid down by proliferating lens epithelial cells (LECs). These opacities were in turn surrounded by interlenticular Elschnig pearl-type opacities contiguous with the same material filling the periphery of the capsular bag. The IOL complexes were very adherent to the capsular bag and they had to be separated with the help of high viscosity viscoelastic before a single one piece PMMA IOL implantation via large limbal incisions. The sample of anterior capsule showed a ridge configuration from the piling of LECs in the site of apposition with the anterior capsule and cells showing different characteristics on either side of the ridge.

CONCLUSION

Cellular proliferation, deposition of ECM from proliferating LECs, and capsular changes induced by cell metaplasia may lead to ILO formation in piggyback AcrySof IOLs. Careful separation of the AcrySof IOL complex from the capsule, meticulous clean up of the proliferating material, and implantation of single or dual in the bag PMMA IOLs through a large incision with capsulorrhexis enlargement may help in the prevention of recurrence of interface opacification.

Piggyback intraocular lens implantation

The piggyback method of implanting two intraocular lenses in one eye has been successfully expanded to address pseudophakic refractive error in normal eyes and eyes that have undergone post-penetrating keratoplasty. Piggyback implantation has been combined with the use of newly available minus-power lenses to provide appropriate power for a cataract patient with keratoconus, as well as to correct pseudophakic myopia. The phenomenon of increased depth of focus in piggybacks may be explained by a contact zone between the lenses. The late complication of inter-lenticular cellular growth with resultant hyperopic shift, opacification, and loss of vision has recently become a concern.