Clear lens extraction for the correction of high refractive error

Retinal detachment after refractive lens exchange: A narrative review

Refractive lens exchange (RLE) allows to correct ametropias and presbyopia by replacing the crystalline lens with an extended depth of focus or multifocal intraocular lens (IOL). Retinal detachment (RD) is one of the most serious adverse events after RLE. This study aimed to review the evidence related to the risk of RD after RLE and clinical outcomes. A search using PubMed and a snowball search approach was conducted to identify articles and case reports. According to the literature, the risks of RD should be considered in patients <60 years old with axial lengths >23 mm. Only nine articles reported visual acuity (VA) after RD in RLE, and only 25% of eyes had a VA > 20/40. Considering that the decrease in VA might be uniform for all types of IOLs after RD, surgeons should focus on selecting the patient to prevent RD rather than on a particular IOL optical design based on the potential risk of DR.

Cataracts

94 million people are blind or visually impaired globally, and cataract is the most common cause of blindness worldwide. However, most cases of blindness are avoidable. Cataract is associated with decreased quality of life and reduced life expectancy. Most cases of cataract occur after birth and share ageing and oxidative stress as primary causes, although several non-modifiable and modifiable risk factors can accelerate cataract formation. In most patients, phacoemulsification with intraocular lens implantation is the preferred treatment and is highly cost-effective. There has been an increase in the use of comprehensive cataract surgical services, including diagnoses, treatment referrals, and rehabilitation. However, global inequity in surgical service quality is still a limitation. Implementation of preoperative risk assessment, risk reduction strategies, and new surgical technologies have made cataract surgery possible at an earlier stage of cataract severity with the expectation of good refractive outcomes. The main challenge is making the service that is currently available to some patients accessible to all by use of universal health coverage.

Modern Phacoemulsification and Intraocular Lens Implantation (Refractive Lens Exchange) Is Safe and Effective in Treating High Myopia

Improved efficacy, predictability, and safety of modern phacoemulsification have resulted in cataract surgery being considered as a refractive procedure. Refractive lens exchange by definition is a surgery aimed at replacing the cataractous or clear crystalline lens with an intraocular lens (IOL) in cases of high ametropia. The excellent intraocular optics of this procedure provide a better visual outcome as compared with laser refractive surgery in high myopia. With advances in technology and IOL formulas, the predictability of refractive outcome after cataract surgery in high myopes has improved. The option of addressing presbyopia using multifocal/accommodating IOLs or monovision results in patients achieving reasonable spectacle independence. The most important concern with respect to phacoemulsification in high myopia is the risk of pseudophakic retinal detachment. High myopia is an independent risk factor for retinal detachment, and recent publications have reported a much lesser risk of retinal detachment specifically attributable to phacoemulsification in high myopes, especially if a thorough posterior segment evaluation is done and patients are followed up until development of complete posterior vitreous detachment. Refractive lens exchange is an effective and safe option to correct high myopia and can significantly improve quality of life in select patients.

Clear lens phacoemulsification combined with vitrectomy to correct high myopia: four years of follow-up

PURPOSE

To evaluate the outcome, intraoperative and postoperative complications of refractive lens exchange (RLE) by phacoemulsification with posterior chamber intraocular lens (IOL) implantation combined with simultaneous pars plana vitrectomy (PPV) in the management of high myopia.

METHODS

This prospective study consisted of 45 eyes of 26 patients with preoperative myopia greater than -12.5 dpt. Clear lens phacoemulsification with IOL implantation surgery was combined with PPV. Main outcome measures were best-corrected visual acuity (BCVA), stability of the spherical equivalent (SE) and complications at follow-up.

RESULTS

The combined procedure of clear lens phacoemulsification combined with PPV has a favorable outcome with acceptable SE predictability and improvement in BCVA. The postoperative BCVA was 0.67 ± 0.21 compared to 0.15 ± 0.10 preoperatively (p < 0.001). The mean postoperative SE was -1.6 ± 0.9 dpt, showing a significant difference when compared with a mean value of -20.0 ± 5.2 dpt before the operation (p < 0.001). During the follow-up, all IOLs were placed stably in the bag with no capsular tear occurring and only 1 case (2.2%) developed retinal detachment.

CONCLUSION

RLE and implantation of an IOL combined with simultaneous PPV is a reasonable refractive surgery option for middle-aged patients with high myopia.

Posterior chamber phakic intraocular lens (ICL) for hyperopia: Ten-year follow-up

PURPOSE

To evaluate the long-term safety, efficacy, predictability, and stability of implantation of a Collamer implantable contact lens (ICL) (Staar) to correct hyperopic refractive errors.

SETTINGS

Ophthalmology Department, Santa Rita Hospital, Vercelli, Italy.

METHODS

Fifty-nine eyes of 34 patients with hyperopia had implantation of an ICL. Patients were examined preoperatively (baseline) and 1 day, 1 week, 1, 3, and 6 months, and 1, 2, 4, 6, 8, and 10 years postoperatively. Main outcome measures were subjective and objective refractions, uncorrected visual acuity, best corrected visual acuity (BCVA), variation in intraocular pressure (IOP), anterior chamber depth (ACD), variation in endothelial cells, adverse events, and patient satisfaction.

RESULTS

Nine patients had ICL implantation in 1 eye and 25 patients, in both eyes. Preoperatively, the spherical equivalent (SE) was between +2.75 diopters (D) and +11.75 D and astigmatism was between +0.50 D and +1.00 D. The mean SE of the manifest refraction was +0.07 +/- 0.54 D; refraction stabilized quickly and remained stable throughout the follow-up period. At 10 years, the safety index was 111 and the efficacy index, 96.8. Of the eyes, 86.5% had a change in SE refraction within +/-0.50 D; 1.6% lost 1 Snellen line of BCVA. The mean endothelial cell loss was 4.7%, which remained almost unchanged throughout the follow-up period. The mean variation in ACD was -14.9% and in IOP, +5.3%.

CONCLUSIONS

The results confirmed the long-term safety, efficacy, accuracy, and predictability of ICL implantation for hyperopia. The Collamer material was well tolerated in all eyes.

Surgical Correction of Hyperopia

Surgical attempts to correct hyperopia have yielded varying results over the last 130 years. These techniques include the reshaping of the cornea through incisions, burns, or lamellar cuts with removal of peripheral tissue; the addition of central inlays; laser ablations; and the replacement of the crystalline lens. By examining the success of each surgical technique, the refractive surgeon may be able to make an informed decision on its indications and limitations, based on the specific patient's characteristics. Reporting the outcomes and complications of hyperopic surgery will help refine our approach to the management of an increasingly hyperopic and presbyopic population.

Intraokularlinsen zur Korrektur von Refraktionsfehlern

In this overview, the current status of intraocular lens surgery to correct refractive error is reviewed. The interventions are divided into additive surgery with intraocular lens implantation without extraction of the crystalline lens (phakic intraocular lens, PIOL) or removal of the crystalline lens with implantation of an IOL (refractive lens exchange, RLE). Phakic IOLs are constructed as angle-supported or iris-fixated anterior chamber lenses and posterior chamber lenses which are fixated in the ciliary sulcus. The implantation of phakic IOLs has been demonstrated to be an effective, safe, predictable and stable procedure to correct higher refractive errors. Complications are rare and differ for the three types of PIOL; for posterior chamber lenses these are mainly cataract formation and pigment dispersion. RLE is preferable in cases of high ametropia in which the natural lens has lost its accommodative effect. The main complications for myopic RLA include retinal detachment, while hyperopic refractive lens exchange may be associated with surgical problems in the narrower anterior eye segment.

Intraokularlinsen zur Korrektur von Refraktionsfehlern

In this overview, the current status of intraocular lens surgery to correct refractive error is reviewed. The interventions are divided into additive surgery with intraocular lens implantation without extraction of the crystalline lens (phakic intraocular lens, PIOL) or the removal of the crystalline lens with implantation of an IOL (refractive lens exchange, RLE). Phakic IOLs are constructed as angle-supported or iris-fixated anterior chamber lenses and posterior chamber lenses that are fixated in the ciliary sulcus. The implantation of phakic IOLs has been demonstrated to be an effective, safe, predictable and stable procedure to correct higher refractive errors. Complications are rare and differ for the three types of PIOL; for anterior chamber lenses these are mainly pupil ovalization and endothelial cell loss.

Refractive lens exchange combined with pars plana vitrectomy to correct high myopia

PURPOSE

To describe the results of refractive lens exchange (RLE) combined with simultaneous pars plana vitrectomy (PPV) in the management of severe myopia.

METHODS

This retrospective study comprised 14 eyes of eight patients who had RLE to treat myopia of -19.0+/-5.4 diopters (D). Phacoemulsification, posterior chamber intraocular lens (IOL) implantation, and standard three-port vitrectomy were performed. Mean postoperative follow-up time was 30 months (range 12-49).

RESULTS

The postoperative best-corrected visual acuity (BCVA) was 0.68+/-0.23 compared to 0.37+/-0.24 preoperatively. There was no postoperative decrease in visual acuity in any eye. Mean postoperative spherical equivalent was -0.7 D (+/-1.6). At 30 months mean follow-up time, the spherical equivalents of nine eyes (64.3%) were within +/-1 D of emmetropia. There was no significant change in astigmatism due to operative procedures. During the 30 months follow-up period three eyes (21.4%) required neodymium : yttrium-aluminium-garnet (Nd : YAG) capsulotomy for posterior capsule opacification. No retinal detachments or cases of cystoid macular oedema (CME) were observed during the follow-up.

CONCLUSION

RLE was effective in correcting severe myopia. The simultaneously performed PPV may reduce the risk of postoperative retinal detachment. This was a pilot study, to draw definitive conclusions a prospective study has to be initiated.

Phakic refractive lens implantation in high myopic patients: one-year results

PURPOSE

To evaluate the efficacy and safety of implantation of a new posterior chamber phakic refractive lens (PRL, Ciba Vision Surgical) in highly myopic eyes.

SETTING

Department of Ophthalmology, Medical School, University of Crete, Vardinoyannion Eye Institute of Crete, Crete, Greece.

METHODS

Thirty-four myopic eyes of 19 patients were treated for high myopia with implantation of a silicone PRL in the posterior chamber. Mean patient age was 29.0 years +/- 7.9 (SD) (range 18 to 44 years). Manifest refraction in spherical equivalent (MR), uncorrected (UCVA) and best corrected (BCVA) visual acuity (decimal scale), intraocular pressure, higher-order aberrations (root-mean-square [RMS] wavefront error measured with a Shack-Hartmann wavefront sensor WASCA analyzer [Carl Zeiss, Meditec]), possible complications, and subjective symptoms were evaluated.

RESULTS

Phakic refractive lenses were successfully implanted in all eyes. Mean follow-up was 17.17 +/- 3.76 months (range 12 to 24 months). There was a statistically significant reduction in the MR (from -14.70 D +/- 2.65 D [range -20.75 D to -10.50 D] to -0.61 D +/- 0.89 D [range -2.25 D to 1.00 D]) (P<.001). Twenty-seven (79%) and 15 eyes (44%) were within +/-1.00 D and +/-0.50 D of target refraction, respectively. Mean UCVA significantly improved (from counting fingers to 0.62 +/- 0.28 (range 0.08 to 1.20) (P<.001). Mean BCVA also improved from 0.70 +/- 0.24 (range 0.10 to 1.00) to 0.85 +/- 0.24 (range 0.10 to 1.20) (P<0.001). Overall, there was a mean increase in BCVA of 1.5 +/- 1.5 lines (range loss of 2 lines to gain of 5 lines). There was no statistically significant difference in higher-order aberrations after PRL implantation (pre-PRL RMS: 0.18 microm +/- 0.08 microm [range 0.09 microm to 0.38 microm]; post-PRL RMS: 0.21 microm +/- 0.08 microm; [range 0.05 microm to 0.38 microm]) (P =.12).

CONCLUSION

The PRL showed encouraging results in treating high myopia. Additional patients and longer follow-up period are needed to detect the long-term efficacy and safety of this refractive lens.

Outcome after treatment of ametropia with implantable contact lenses

OBJECTIVE

To evaluate long-term results after insertion of implantable contact lenses (ICLs) in phakic eyes.

DESIGN

Prospective, noncomparative, interventional case series.

PARTICIPANTS

Seventy-five phakic eyes (65 myopic, 10 hyperopic eyes) of 45 patients aged 21.7 to 60.6 years were included.

INTERVENTION

STAAR Collamer Implantable Contact Lenses (STAAR Surgical Inc., Nidau, Switzerland) were implanted for correction of high myopia and hyperopia.

MAIN OUTCOME MEASURES

Uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA), and intraocular pressure (IOP) were determined. Presence of lens opacification and the distance between the ICL and the crystalline lens were assessed by slit-lamp examination before surgery and at 1, 3, 6 months, and yearly after lens implantation.

RESULTS

Preoperative mean spherical equivalent was -16.23+/-5.29 diopters (D) for myopic eyes and +7.88 +/-1.46 D for hyperopic eyes. After ICL implantation, mean residual refractive error was -1.77+/-2.17 D in myopic patients and +0.44+/-0.69 D in hyperopic patients. Preoperative mean UCVA was Snellen 0.03+/-0.03 for myopic patients and Snellen 0.12+/-0.16 for hyperopic patients. Preoperative mean BCVA was Snellen 0.49+/-0.23 for myopic patients and Snellen 0.82+/-0.23 for hyperopic patients. After ICL implantation, mean UCVA up to the end of individual observation time was Snellen 0.36+/-0.36 for myopic patients and Snellen 0.58+/-0.28 for hyperopic patients. Mean BCVA was Snellen 0.73+/-0.26 for myopic and Snellen 0.80+/-0.24 for hyperopic patients. Mean preoperative IOP was 14.2+/-2.7 mmHg, and mean postoperative IOP was 13.46+/-2.1 mmHg over all follow-up investigations. The main complication was the development of subcapsular anterior opacifications of the crystalline lens in 25 eyes (33.3%), 2 of which showed direct contact to the ICL. Eleven eyes (14.7%) were stable in opacification and 14 eyes (18.7%) had progressive opacifications. The median time to opacification was 27.1 months. In 8 patients (10.7%), the subjective visual impairment mandated cataract surgery.

CONCLUSIONS

The most significant long-term complication after ICL implantation is the formation of opacifications of the crystalline lens with the risk of the necessity of subsequent cataract surgery (10.7%). Old age, female gender, and contralateral opacification are independent significant risk factors for early formation of opacifications in this patient group.

Pseudophakic retinal detachment

Pseudophakic retinal detachment is a rare, but potentially serious, complication of cataract surgery. The incidence of pseudophakic retinal detachment following current surgical techniques of cataract extraction, including extracapsular cataract extraction by nuclear expression and phacoemulsification, is lower than that found after intracapsular cataract extraction. The risk of pseudophakic retinal detachment appears to be increased in myopic patients, in those patients in whom vitreous loss had occurred at the time of cataract surgery, and in patients undergoing Nd:YAG posterior capsulotomy. Most cases present to the clinician when the macula is already detached and the central vision is affected. When evaluating patients with pseudophakic retinal detachment, the fundal view is often impaired by anterior or posterior capsular opacification, reflections related to the intraocular lens, or poor mydriasis. Scleral buckling, pneumatic retinopexy, and primary pars plana vitrectomy, with or without combined scleral buckling, are the surgical techniques used to treat pseudophakic retinal detachment. Anatomical success rates are high after vitreo-retinal surgery for pseudophakic retinal detachment, although a smaller proportion of patients recover good vision following surgery.

Actual and theoretical risks for visual loss following use of the implantable contact lens for moderate to high myopia

PURPOSE

To estimate the actual and theoretical risks for visual loss associated with use of the implantable contact lens (ICL).

SETTING

Multicenter clinical trial data.

METHODS

An established model for estimating the risk for visual loss associated with retinal detachment (RD) following clear lens extraction (CLE) was modified to be applicable to the ICL. The risk for developing RD and the outcomes of RD surgery based on current lens extraction and RD repair techniques were updated. Non-RD-related risks for pseudophakia based on United States Food and Drug Administration (FDA) guidelines, actual visual loss data from the FDA ICL study, and calculated risks assuming a large future risk (10 times the current risk) of cataract development were also added.

RESULTS

The additional risk for visual loss due to cataract surgery is estimated at 0.19% and for subsequent RD assuming 10 times the current rate of cataract is 0.37%. Using an ultraconservative (high) model and adding the actual loss observed with the ICL, the total risk is 1.39%. The risk increases by 0.5% to 0.6% with each 10% increase in cataract incidence (eg, 10% to 20%, 20% to 30%). The risk for visual loss with CLE and/or laser in situ keratomileusis/photorefractive keratectomy in the same range of myopia is possibly 3.0% to 6.5%.

CONCLUSIONS

The ICL represents a viable alternative to currently available refractive procedures based on an analysis of the risk for visual loss.

Refractive lens exchange with a multifocal intraocular lens

Refractive lens exchange with a multifocal intraocular lens is becoming a more popular method of refractive surgery in the presbyopic patient. The limitations of keratorefractive surgery have led to a resurgence of lens exchange surgery for patients with prescriptions outside the limits of corneal refractive procedures, in addition to patients with routine refractive errors requesting a surgical procedure to achieve emmetropia and also address presbyopia. Side effects of multifocal technology including unwanted photic phenomena and deterioration in contrast sensitivity are being further defined and evaluated to better assess the effects of these intraocular lenses on functional vision and patient satisfaction. Attention to detail in regards to proper patient selection, preoperative measurements, intraoperative technique, and postoperative management will ultimately result in excellent outcomes and improved patient acceptance of this effective technique.

Retinal detachment after cataract extraction and refractive lens exchange in highly myopic patients

PURPOSE

To assess the refractive effects and incidence of postoperative complications in patients with high myopia after cataract extraction.

SETTING

University Eye Clinic, Trieste, Italy.

METHODS

This noncomparative retrospective study comprised all eyes (N = 388) having cataract extraction and implantation of an intraocular lens with a power less than 11.0 diopters (D) between 1986 and 1999. The preoperative and postoperative refractions; preoperative, postoperative, and final best corrected visual acuity (BCVA); and postoperative complications were analyzed. The mean follow-up was 47.16 months +/- 32.83 (SD) (range 8 to 146 months).

RESULTS

Phacoemulsification was performed in 237 eyes, extracapsular cataract extraction in 147 eyes, and intracapsular cataract extraction in 4 eyes. The mean preoperative BCVA was 0.20 +/- 0.21 and the mean postoperative BCVA, 0.58 +/- 0.32. At the final evaluation, the mean BCVA was 0.50 +/- 0.33. The mean refraction was -15.95 +/- 5.86 D preoperatively and -2.00 +/- 1.62 D postoperatively. One eye (0.26%) developed a retinal detachment postoperatively. Of the 127 eyes (32.73%) having a neodymium:YAG laser capsulotomy for posterior capsule opacification, 1 had a macular retinal hole. Posterior detachment of the vitreous occurred in 78.6% of cases. Peripheral retinal photocoagulation was required in 8 cases postoperatively.

CONCLUSION

Refractive lens exchange led to good functional results and a low incidence of postoperative complications and can thus be regarded as a viable technique to correct high myopia associated with cataract. However, further study is required before it can be routinely recommended for the correction of high myopia in eyes with a transparent crystalline lens.

Retinal detachment after clear lens extraction for high myopia: seven-year follow-up

OBJECTIVE

To prospectively evaluate the incidence of complications, particularly retinal detachment, 7 years after clear lens extraction (CLE) for myopia greater than -12 diopters (D).

DESIGN

Extended follow-up of noncomparative case series.

PARTICIPANTS

Fifty-two eyes of 30 patients with preoperative myopia greater than -12 D, best-corrected visual acuity (BCVA) of 20/100 or better, and intolerance of contact lenses.

INTERVENTION

Patients with lattice degeneration, retinal tear, or hole underwent photocoagulation before CLE. The authors performed phacoemulsification through a 3.2-mm-wide incision using primary irrigation and aspiration, widened the incision to 6.5 mm, and implanted a one-piece polymethyl methacrylate intraocular lens (IOL).

MAIN OUTCOME MEASURES

The BCVA, uncorrected visual acuity (UCVA), stability of spherical equivalent (SE), neodymium:YAG (Nd:YAG) capsulotomy rate, and complications (especially retinal detachment).

RESULTS

At 7 years, the SEs of 29 eyes (59.1%) were within +/-1.0 D of emmetropia and 42 eyes (85.7%) were within +/-2.0 D. Mean SE was -1.01 D (+/-0.94). At 7 years, mean UCVA was 20/80 compared with 20/66 at 1 year. BCVA and UCVA were better in eyes with open capsules versus intact capsules. During the 7 years, 30 eyes (61.2%) required capsulotomy for opacification. Mean time for capsulotomy was 48.4 months after CLE. The authors performed ten argon laser retinal treatments after surgery, with all but one in the first postoperative year. The overall incidence of posterior vitreous detachment was 16.3%. The incidence of retinal detachment during the 7 years was 4 of 49 eyes, or 8.1% (vs. 2.0% at 4 years). One patient had bilateral retinal detachments.

CONCLUSION

Despite advances in surgical technique, retinal detachment remains a major concern after CLE for high myopia. In the authors' series, the incidence of retinal detachment after CLE was nearly double that estimated for persons with myopia greater than -10 D who do not undergo surgery. Although CLE has advantages, including rapid and predictable visual rehabilitation, stable refraction, the ability to replace the IOL, and often superb optical quality with no irregular astigmatism, it is invasive and can result in severe vision loss. Long and continuous follow-up of the outcomes of CLE for high myopia is absolutely necessary before the authors can consider CLE as a routine option for patients with high myopia.

Refractive lensectomy to correct ametropia

PURPOSE

To assess the postoperative outcome of refractive lensectomy for ametropia.

SETTING

Pacific Eye Center, Brisbane, Australia.

METHODS

One hundred thirty-eight cases of refractive lensectomy performed from September 1994 to September 1997 by 1 surgeon were analyzed retrospectively. Preoperative refractive spherical equivalent (SE) ranged from -0.25 to -23.75 diopters (D) in the myopic group and from +0.25 to +11.62 D in the hyperopic group. In all cases with a low SE, the astigmatism was greater than -2.00 D. Eyes were divided into 6 groups by the preoperative SE.

RESULTS

Overall, 90.0% of eyes achieved an uncorrected visual acuity of 20/40 or better; 81.2% achieved 20/30 or better. Postoperative SE was within +/- 2.0 D of emmetropia in 93.5% of eyes and within +/- 1.0 D in 78.3%. The postoperative incidence of retinal detachment was 0.7%; intraocular lens (IOL) exchange, 2.8%; late uveitis, 0.7%; piggyback IOL, 2.1%; and neodymium: YAG capsulotomy, 8.0%. No cystoid macular edema, capsule tear, or endophthalmitis was seen.

CONCLUSION

Refractive lensectomy can achieve excellent visual acuity and refractive outcomes with few complications. The surgery can be considered in selected patients with myopia, hyperopia, and astigmatism and to correct residual ametropia after refractive surgery.

Analysis of preoperative factors predictive of visual acuity in axial myopia

PURPOSE

To identify the factors predicting visual acuity after cataract surgery in patients with high myopia.

SETTING

Departments of Ophthalmology, Showa University School of Medicine and Showa University Fujigaoka Hospital, Kanagawa, Japan.

METHODS

Stepwise regression analysis was used to identify the factors determining the visual acuity in 940 eyes with an axial length of 27.0 mm or longer having cataract surgery. Using a formula derived from the stepwise regression analysis, the predicted postoperative visual acuity was compared with the actual value measured in another group of 104 eyes.

RESULTS

Five factors were identified to significantly determine postoperative visual acuity: axial length, age, corneal opacity, refractive power of the cornea, and history of retinal detachment surgery. There was a significant relationship between predicted and actual postoperative visual acuities (r = .51, P < .001). Postoperative visual acuity was similar in 63% of cases.

CONCLUSION

The results showed that at least five factors determine visual acuity after cataract surgery in patients with high myopia.

Posterior Chamber Phakic Intraocular Lens for Hyperopia of +4 to +11 Diopters

PURPOSE

To examine the efficacy, predictability, stability, and safety of posterior chamber phakic intraocular lens (IOL) implantation in eyes with high hyperopia.

METHODS

We analyzed the results of 24 eyes that received a posterior chamber hydrogel-collagen plate phakic IOL (Staar Collamer Implantable Contact Lens, ICL) for the correction of hyperopia with the goal of emmetropia. Mean follow-up was 8.4 months (range, 1 to 18 mo).

RESULTS

The mean preoperative spherical equivalent refraction was +6.51 +/- 2.08 D (range, +3.75 to +10.50 D). Mean postoperative spherical equivalent refraction at last examination was -0.39 +/- 1.29 D (range, +1.25 to -3.88 D), with 79% (19 eyes) within +/-1.00 D and 58% (14 eyes) within +/-0.50 D of emmetropia. Postoperative uncorrected visual acuity at last examination was 20/20 or better in 8% (two eyes) and 20/40 or better in 63% (15 eyes). A gain of two or more lines of spectacle-corrected visual acuity was seen in two eyes (8%) at last examination. One eye (4%) lost two or more lines of spectacle-corrected visual acuity due to progressive neovascular glaucoma initiated by early postoperative pupillary block.

CONCLUSION

Posterior chamber phakic IOL implantation with the Staar Collamer plate lens is an effective method for correcting high hyperopia. Large, patent iridotomies are important in hyperopic eyes to lower the risk of postoperative pupillary block. Improved phakic IOL power calculation formulas will refine predictability of refractive outcome.

Clear Lensectomy and Intraocular Lens Implantation for Hyperopia from +7 to +14 Diopters

BACKGROUND

Our results of clear lens extraction and intraocular lens implantation to correct hyperopia from +6.75 to +13.75 D are presented, as well as evaluation of two intraocular lens calculation formulae.

METHODS

Clear lens extraction and posterior chamber intraocular lens implantation was performed in 35 normally sighted eyes of 21 patients with a mean baseline hyperopic spherical equivalent refraction of +9.19 +/- 0.34 D (range +6.75 to +13.75 D). The refractive goal was -1.50 D, using the SRK II formula in 17 eyes and the SRK-T formula in 18 eyes. Follow-up was up to 5 years.

RESULTS

Mean uncorrected visual acuity after surgery was 0.8 (range 0.5 to 1.0). Stability of refraction was noted from the second month after surgery. No eyes lost any lines of spectacle-corrected visual acuity. Using the SRK II formula, 100% of eyes were within +/-1.00 D of emmetropia and with the SRK-T formula, 83.3% for a combined 91.4% of eyes within +/-1.00 D of emmetropia. One eye required intraocular lens exchange and another eye required photorefractive keratectomy for myopia. Both procedures were necessitated by an intraocular lens miscalculation of more than +/-2.00 D. Nineteen eyes (54.2%) developed posterior capsular opacification and were treated with Nd:YAG laser capsulotomy.

CONCLUSION

Clear lens extraction is a safe, effective, and predictable procedure for the treatment of hyperopia from +6.75 to +13.75 D. The SRK II formula proved slightly superior to the SRK-T in intraocular lens calculation when using the "-1.50 D rule."

Laser in situ Keratomileusis to Correct Hyperopia from +4.25 to +8.00 Diopters

OBJECTIVE

To evaluate the efficacy and predictability of laser in situ keratomileusis (LASIK) for hyperopia in a prospective study of 54 eyes of 29 patients.

METHODS

Before LASIK, 44 eyes (81.48%) had a spectacle-corrected visual acuity of 20/20 or better, and 54 eyes (100%) had 20/40 or better. Surgery was performed under topical anesthesia using the Keracor 116 excimer laser and Chiron automated corneal shaper. Mean follow-up was 19 months.

RESULTS

Mean baseline uncorrected hyperopia was +6.50 +/- 1.33 D (range, +4.25 to +8.00 D). Mean uncorrected manifest spherical equivalent refraction was +0.44 +/- 1.95 D at 18 months after LASIK. Twenty-one eyes (38.8%) were within +/-0.50 D of emmetropia, 41 eyes (75.92%) were within +/-1.00 D, and 47 eyes (87.03%) were within +/-2.00 at 18 months after LASIK. Uncorrected visual acuity was 20/20 or better in eight eyes (14.81%) and 20/40 or better in 36 eyes (66.66%) 18 months after LASIK. Regression and undercorrection of more than 2.00 D occurred in seven eyes (12.9%) between the 3 and 6 month examinations; three of these seven eyes (42.8%) required retreatment to correct residual hyperopia. Three eyes (6.8%) lost two or more lines of spectacle-corrected visual acuity.

CONCLUSION

Excimer laser keratomileusis in situ with the Keracor 116 appears to be an effective and safe procedure to decrease low and moderate hyperopia, but the predictability of the procedure needs improvement.

Clear lens extraction to correct hyperopia

PURPOSE

To evaluate the effectiveness and safety of clear lens extraction with intraocular lens (IOL) implantation to correct hyperopia and to determine the most accurate and predictable method of IOL power selection.

SETTING

The Eye Institute of Utah, Salt Lake City, Utah, USA.

METHODS

The outcome of 20 phacoemulsification and IOL implantation procedures was assessed at a mean follow-up of 23.2 months (range 3 to 60 months). Intraocular lens power and predicted refraction were retrospectively evaluated in each eye with the SRK II and Holladay formulas with different attempted refractions based on the stabilized postoperative refraction.

RESULTS

Uncorrected visual acuity (UCVA) improved from 20/200 preoperatively to 20/30 postoperatively. At the final examination, 89% of eyes achieved 20/40 or better UCVA. All eyes had 20/25 or better best corrected visual acuity (BCVA). No eye lost two or more Snellen lines of BCVA. There were no surgical or postoperative complications. The Holladay formula was more accurate than the SRK II formula. With the Holladay formula aiming for -1.00 diopter (D), the predicted mean postoperative spherical equivalent would be -0.21 D +/- 0.89 (SD); with the SRK II aiming for -1.50 D, it would be +0.43 +/- 1.10 D. The Holladay formula reduced the chance of postoperative residual hyperopia.

CONCLUSION

Clear lens extraction with IOL implantation was an effective, safe procedure for the correction of hyperopia. However, this method was less accurate and less predictable for hyperopia below +3.00 D. With the Holladay formula aiming for -1.00 D, good visual and refractive results can be expected. Further study with a larger sample of patients and longer follow-up is needed to assess long-term safety and effectiveness.

Pseudophakic retinal detachment in high axial myopia

PURPOSE

To investigate the effect of extracapsular cataract surgery with intraocular lens (IOL) implantation and neodymium:YAG (Nd:YAG) laser posterior capsulotomy on the rate of retinal detachment (RD) in myopic eyes with an axial length of 27 mm or more.

SETTING

Department of Ophthalmology, University of Giessen, Germany.

METHODS

This retrospective, nonrandomized study comprised the records of 386 consecutive surgical procedures in 275 patients performed between December 1985 and December 1993. In May 1994, all patients were asked by a mailed questionnaire whether they had had an RD in either eye or laser treatment for posterior capsule opacification. Responses from 190 patients concerning 253 surgical procedures were evaluated.

RESULTS

The pseudophakic RD rate was 0.8% (two cases). One patient developed aphakic RD after IOL explanation. One expulsive choroidal hemorrhage occurred during secondary IOL implantation. Four eyes (1.6%) had vitreous loss, and 74 eyes (29.2%) had an Nd:YAG capsulotomy. Mean axial length was 29.2 mm +/- 1.71 (SD), mean follow-up was 3.8 +/- 2 years, and mean age at surgery was 69.8 +/- 12 years.

CONCLUSION

Pseudophakia with no other risk factor posed little additional risk for RD in eyes with high axial myopia; however, Nd:YAG laser posterior capsulotomy was a risk factor for pseudophakic RD. Complicated surgery, such as a secondary procedure or vitreous loss, and young age were major causative factors.

Clear lensectomy and implantation of a low-power posterior chamber intraocular lens for correction of high myopia: a four-year follow-up

PURPOSE

To evaluate the 4-year postoperative outcomes of patients who are highly myopic who underwent clear lensectomy via phacoemulsification and low power posterior chamber intraocular lens implantation.

METHODS

The authors performed surgery in 52 eyes of 30 patients in which prophylactic retinal treatment, clear lensectomy, and posterior chamber intraocular lens implantation were used to treat high myopia of 12 diopters (D) or greater. A total of 49 eyes of 28 patients were evaluated at the 4-year postoperative timeframe. Visual acuity, complications, and refractive stability were assessed.

RESULTS

The incidence of retinal detachment through 4 years was 1.9%. No new macular complications were observed. Two patients had posterior vitreous detachment without clinical impact between 1 and 4 years after surgery. The incidence of neodymium:YAG (Nd:YAG) capsulotomy was 36.7%. The mean postoperative spherical equivalent was -0.92 D. Four patients had a myopic shift of 0.50 D to 1.00 D from the 1- to 4-year timeframe. Corrected visual acuity of 20/40 or better was achieved in 82% of eyes that had undergone Nd:YAG capsulotomy versus 56% of untreated eyes. Uncorrected visual acuity of 20/100 or better was achieved in 82% of eyes treated with the Nd:YAG laser versus 62% of untreated eyes.

CONCLUSION

Visual acuity and refractive outcomes with clear lensectomy are favorable. Retinal detachment remains the major concern of this procedure. Continuous follow-up of these patients is necessary.

Keratomileusis in situ for high myopia

PURPOSE

To examine the safety and efficacy of myopic keratomileusis in situ (automated lamellar keratoplasty) using an automated microkeratome.

SETTING

Jules Stein Eye Institute and the Department of Ophthalmology, UCLA School of Medicine, Los Angeles, California.

METHODS

A retrospective study was done on 135 consecutive eyes of 91 patients who had keratomileusis in situ for myopia by one surgeon between October 4, 1993, and February 23, 1995. Mean preoperative myopia was 8.30 +/- 2.50 diopters (D) (range 4.50 to 20.50). Follow-up ranged from 1 (108 eyes) to 6 months (52 eyes). No eye had enhancement surgery before 3 months; eyes were dropped from the study at the time of enhancement.

RESULTS

Three months after myopic keratomileusis in situ, the mean difference between attempted and achieved correction was an undercorrection of 0.90 +/- 1.50 D; 32 of 83 eyes were within 1.00 D of attempted correction. Forty eyes were undercorrected by more than 1.00 D, and 11 were overcorrected by more than 1.00 D. Uncorrected visual acuity improved to 20/40 or better in 42 of 83 eyes at 3 months. Best spectacle-corrected visual acuity (BSCVA) declined by two or more lines in 8 of 83 eyes at 3 months and 1 of 52 eyes at 6 months. In eyes with 6 months of follow-up, a mean myopic shift of 0.40 D occurred between 3 and 6 months. Two eyes had clinically significant ingrowth into the interface. The variability in outcome (standard deviation in achieved less attempted correction) at 3 months was 1.70 D in the first 45 cases, 1.20 D in the second 45 cases, and 1.10 D in the last 45 cases.

CONCLUSION

Myopic keratomileusis in situ is relatively effective and safe for the correction of high myopia; however, a mild loss of BSCVA is not uncommon in the early postoperative period. Surgeon experience may be important for refractive accuracy.

First results of cataract surgery and implantation of negative power intraocular lenses in highly myopic eyes

OBJECTIVES

To determine whether cataract surgery in highly myopic eyes should be considered high-risk surgery and whether exact intraocular lenses (IOLs) should be implanted if negative power is required. SITE: Klinik Dardenne, Bonn-Bad Godesberg, Germany.

METHOD

We retrospectively studied 32 eyes of 27 highly myopic patients who had cataract surgery and posterior chamber IOL implantation. Intraocular lens power varied from -1.0 to -8.0 diopters (D), and eye length varied from 31.0 mm to more than 35.0 mm. Follow-up ranged from 6 to 36 months. Patients were analyzed for postoperative visual acuity and for intraoperative and postoperative complications.

RESULTS

No patients experienced intraoperative complications. Posterior capsule opacification, which occurred in 14 eyes, was the only postoperative complication in the anterior or posterior segments. Ninety-four percent of eyes achieved improved best corrected visual acuity, and 69% of eyes were within 1.0 D of the refractive target.

CONCLUSIONS

Cataract surgery can be performed in highly myopic eyes without intraoperative complications. A posterior chamber IOL should be implanted for postoperative refraction and intraocular stability, even if negative lens power is required.

Comparison of results of excimer laser correction of all degrees of myopia at 12 months postoperatively. The Melbourne Excimer Laser Group

To examine prospectively the efficacy and safety of photorefractive keratectomy and photoastigmatic refractive keratectomy.

METHODS

We treated 645 eyes (440 patients) with a VisX Twenty/Twenty excimer laser and followed them up for 12 months.

RESULTS

The percentage of eyes with myopia between -5.01 and -10.00 diopters spherical equivalent within 1 and 2 diopters of emmetropia at 12 months was 65% (123 of 189) and 90% (170 of 189), respectively, whereas the corresponding percentages for eyes with myopia greater than -10.00 diopters spherical equivalent were 39% (16 of 41) and 56% (23 of 41), and for eyes with myopia of -5.00 diopters spherical equivalent or less, 87% (238 of 273) and 99% (270 of 273), respectively. Uncorrected visual acuity of 20/20 and 20/40 or better at 12 months was attained in 47% (129 of 273) and 87% (237 of 273) of the eyes with myopia -5.00 diopters spherical equivalent or less, respectively. At 12 months, 48 (25%) of the 189 eyes with myopia between -5.01 and -10.00 diopters spherical equivalent had uncorrected visual acuity of 6/6 or better and 135 (71%), 6/12. At 12 months, one eye (2%) with myopia greater than -10.00 diopters spherical equivalent had uncorrected visual acuity of 6/6 and 11 (27%) of 41 eyes, 6/12. Ten (4%) of the 273 eyes with myopia of -5.00 diopters spherical equivalent or less, 15 (8%) of the 189 eyes with myopia between -5.01 and -10.00 diopters spherical equivalent, and nine (22%) of the 41 eyes with myopia greater than -10.00 diopters spherical equivalent had lost two or more LogMAR lines of best-corrected visual acuity at 12 months.

CONCLUSION

Excimer laser surgery is highly reliable for myopia of -5.00 diopters spherical equivalent or less and is less reliable for greater myopia.

Phacoemulsification with intraocular lens implantation in high myopia

PURPOSE

To assess phacoemulsification and posterior chamber intraocular lens (IOL) implantation in highly myopic eyes and to compare the results of sutureless scleral tunnel incision and sutured scleral incision techniques.

SETTING

The Eye Institute of Utah, Salt Lake City.

METHODS

A series of 109 highly myopic eyes (axial length over 26.00 mm) were reviewed at a mean postoperative follow-up of 27 months.

RESULTS

Postoperative corrected visual acuity was 20/40 or better in 94% of eyes, and uncorrected visual acuity was 20/40 or better in 77% of eyes. Posterior capsule opacification developed in 50% of eyes; 95% of these had neodymium:YAG (Nd:YAG) laser capsulotomy. Cystoid macular edema occurred in two eyes, and one eye developed retinal detachment following Nd:YAG capsulotomy. Eyes that had sutureless scleral tunnel incisions attained earlier postoperative rehabilitation of visual acuity and stabilization of astigmatism than did patients who had sutured scleral incisions.

CONCLUSIONS

The results of this study of highly myopic eyes indicate that treating retinal pathology preoperatively and using the sutureless procedure, phacoemulsification, and in-the-bag IOL placement lead to good visual outcome, a lower rate of retinal complications, and a more stable wound.

Lamellar Keratoplasty for Hyperopia

PURPOSE

Lamellar keratoplasty for hyperopia (automated lamellar keratoplasty for hyperopia) can correct hyperopia by weakening the cornea with a deep lamellar resection. The safety and efficacy of the procedure is uncertain.

METHODS

Twenty-four eyes of 17 patients underwent hyperopic lamellar keratoplasty using the automated corneal shaper (Chiron Corp, Irvine, Calif) by one surgeon using a flap technique. The mean attempted correction was +3.90 +/- 0.90 D (range, +2.00 to +6.00). The eyes were followed for 1 month (23 eyes) to 6 months (17 eyes).

RESULTS

Six months after hyperopic lamellar keratoplasty, the mean difference between attempted and achieved correction was an undercorrection of +1.40 +/- 0.80 diopters (D) with 7 of 17 eyes within 1.00 D of the attempted correction. No eyes were overcorrected, and 15 eyes were undercorrected. In eyes with a refractive goal of emmetropia, uncorrected visual acuity was 20/40 or better in 13 of 15 eyes and 20/20 or better in 8 of 15 eyes. No eye lost two or more lines of spectacle-corrected visual acuity at 3 or 6 months postoperatively. Between 1 and 6 months, there was a mean hyperopic shift of 0.20 D. There was clinically significant epithelial ingrowth into the interface in two eyes.

CONCLUSION

Hyperopic lamellar keratoplasty is an effective method of reducing hyperopia and induces little irregular astigmatism. The nomogram we used produces a consistent undercorrection. Refraction appears to stabilize at 1 month, but longer follow up is necessary to assess stability.