[Intraocular lenses].
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Cataract Extraction↗
Biomedical subjects
G U Auffarth
Publications and source records attributed to G U Auffarth.
[The life work of Sir Nicholas Harold Lloyd Ridley].
On may 25th 2001 Sir Harold Ridley died at age 94. With him Ophthalmology lost one of the greatest and most influential Ophthalmologist of the post-war time. He is the founder of modern cataract surgery implanting the first intraocular lens after extracapsular cataract extraction 50 years ago. He pioneered in what became one of the most important success stories in Ophthalmology. His vision and concepts managed to succeed against strong opposition worldwide. Modern cataract surgery and modern refractive IOL surgery would not been possible without his contribution. Sir Harold Ridley reached a high age and was therefore able to see his visions become reality and finally receive all honours and awards he deserved over the past 15 years, including the knighthood by Queen Elisabeth II in the year 2000. The following article gives a summary of his biography and contributions to Ophthalmology.
Cataract Extraction↗
[History of the development of intraocular lenses].
Even though cataract surgery has been practiced for over 2000 years, modern cataract surgery started just some 50 years ago. with the first IOL implantation by Sir Harold Ridley. The development of intraocular lenses was accompanied by great successes and disasters. With the fast development of cataract surgical techniques over the past 15 years (ECCE, Phacoemulsification, Capsulorhexis) a successful marriage between IOL-developments and surgery was established. Indication profiles for cataract surgery and IOL implantation extended to more and more patient groups. At this time classical cataract surgery is further developing into refractive intraocular lens surgery to correct higher ametropia in clear lens or phakic eyes. This development was only possible because of the improvements of surgical techniques and implants in classical cataract surgery.
Accommodation, Ocular↗
[Complication profiles of posterior chamber intraocular lenses IOL). An analysis of 586 foldable and 2077 rigid explanted intraocular lenses].
BACKGROUND: Foldable intraocular lenses (IOL) have become increasingly preferred choice for IOL implantation after cataract removal. However, both foldable as well as rigid IOLs are not yet complication-free and may need explanation. MATERIAL AND METHODS: A total of 2663 explanted posterior chamber IOLs (PCIOLs) were accessioned at the Center for Research on Ocular Therapeutics and Biodevices between January 1988 and September 2000. The lenses were examined grossly using a Leitz/Wild M-8-Zoom stereomicroscope. The clinical reasons for explanation were documented for foldable as well as for rigid lenses. RESULTS: Of a total of 2663 explanted PCIOLs, 586 were foldable lenses and 2077 were rigid PMMA lenses The most frequent reason for explantation of all 2663 IOLs studied was decentration/dislocation. Optic and haptic damage and posterior capsule rupture were significantly more often a reason for explantation in several foldable designs compared to rigid PCIOLs. Whereas rigid designs lead more often to corneal decompensation. The percentage of explanted IOLs because of inflammatory reactions decreased significantly from 1994 to 2000. CONCLUSIONS: The complication profiles of rigid and foldable IOLs revealed some apparent differences due to the nature of the IOL biomaterials and designs. IOL optic/haptic damage was a common complication for foldable IOLs, whereas it was only discovered in single digits for rigid PMMA IOLs. The possible explanation for this is, that the soft and flexible biomaterials, from which all the foldable IOLs were manufactured, are easier to be damaged during folding, unfolding and insertion procedure. In our opinion this relative disadvantage of foldable IOLs is by far outweighed by the numerous advantages of the small incision cataract surgery. The decreasing inflammatory reactions can be explained by advances in surgical techniques, especially the secure in-the-bag fixation of IOLs.
Humans↗
[Morphological autopsy findings in human eyes implanted with Ridley intraocular lenses].
BACKGROUND: Sir Harold Ridley's first cataract extraction with implantation of an intraocular lens (IOL) marked the beginning of a major change in the practice of ophthalmology. MATERIAL AND METHODS: Two human autopsy globes implanted with original Ridley IOLs were grossly examined from behind with the Miyake-Apple photographic technique. The anterior segments were evaluated histologically. One Ridley IOL was examined by scanning electron microscopy. RESULTS: Both IOLs maintained a clear visual axis and had been placed in the capsular sac. The right lens was decentered inferiorly, the left IOL was well centered. The posterior capsule showed only minimal capsular opacification. Scanning electron microscopy (SEM) of the explanted IOL showed a smooth, well polished surface. CONCLUSIONS: In this patient Ridley IOLs maintained an ideal visual rehabilitation of 20/20 in both eyes, 22 and 18 years postoperatively. One surprising finding was the presence of a square, truncated optic edge geometry, very similar to that seen in some modern foldable IOLs. In our opinion the absence of posterior capsule opacification of the Ridley IOL may have partially been a result of this nearly sharp optic edge, that we confirmed by SEM. Even 22 years after implantation the Ridley IOL showed a high finish quality. Many of Sir Harold Ridley's early concepts like the IOL placement in the posterior chamber and endocapsular implantation are now the standard of modern cataract surgery.
Aged↗
[Multifocal intraocular lenses. A review].
Modern cataract surgery has developed tremendously during the past 10-15 years. Improved surgical techniques, as well as improved implant materials and designs, have enlarged patient profiles and indications for cataract surgery. This also created much higher expectations from the patients' site. The loss of accommodation is loss of quality of life for presbyopic and especially young pseudophakic patients. Therefore cataract surgery with multifocal IOL implantation is not only of academic interest, but reflects demands and expectations of our patients. Multifocal IOLs have been implanted since 1986, starting with 2-3 zone refractive and diffractive designs. Due to surgical techniques of that time MIOL decentration and surgically induced astigmatism were possible complications. In addition reduced contrast sensitivity and increased glare were common problems of MIOL because of their optical principles. New developments in this field in recent years such as the multizonal, progressive refractive MIOL in combination with improved surgical techniques have overcome those initial problems. Therefore, modern multifocal IOLs can be considered not only for correction of aphakia but also for refractive purposes.
Age Factors↗
[Morphological evaluation of posterior capsule opacification in diffractive multifocal intraocular lenses].
BACKGROUND: Diffractive multifocals belong to the first generation of multifocal intraocular lenses. Dure to their optical principle of diffraction multifocals separate the incoming light on two foci (41%) with 18% loss of scattered light. Therefore, reduced contrast sensitivity and glare have been frequently described with this lens. PATIENTS AND METHODS: We evaluated 42 eyes of 25 patients (age at surgery 63.8 +/- 8.8 years) 3 years after implantation of a Pharmacia 811E diffractive multifocal (MIOL). They were tested for functional results including contrast and glare (Mesoptometer II). In addition 22 eyes were evaluated for posterior capsule opacification (PCO) using digitalized retroilluminations photographs and the EPCP image analysis program. RESULTS: Average visual acuity was 0.77 +/- 0.20 (uncorrected distance), 0.93 +/- 0.21 (corrected distance), 0.94 +/- 0.13 uncorrected near) und 0.98 +/- 0.08 (best corrected near). PCO-values quantified by EPCO were 1.13 +/- 0.59 (Range 0.07 to 2.1). On average 18.1 +/- 14.9% of the optic area showed an opacification grade 1, 35.8 +/- 26.6% grade 2 and 7.7 +/- 17.1% grade 3. Contrast sensitivity showed no patient with contrast level 7 or better for monocular evaluation, but 30% for binocular testing. Only 4% met the criteria for night driving when tested for glare. Spearman correlation did not reveal any significant correlation between PCO-values and visual acuity, contrast sensitivity or glare (all p > 0.24, all r < 0.22). CONCLUSIONS: Patients with diffractive multifocal IOLs showed excellent results for near and distance visual acuity three years after implantation. However, contrast and glare results were poor, probably due to a rather high PCO-rate. Future developments of the lens type should include PCO-reducing factors, such as sharp edge optics and foldable materials.
Aged↗
Eradication of posterior capsule opacification: documentation of a marked decrease in Nd:YAG laser posterior capsulotomy rates noted in an analysis of 5416 pseudophakic human eyes obtained postmortem.
OBJECTIVE: (1) To report the neodymium:yttrium-aluminum-garnet (Nd:YAG) laser posterior capsulotomy rate (%) of eight rigid and foldable intraocular lens (IOL) designs in a series of 5416 pseudophakic human eyes obtained postmortem, accessioned in our center between January 1988 and January 2000. (2) To identify factors that are instrumental in reducing the incidence of posterior capsule opacification, (PCO, secondary cataract) and hence the need for Nd:YAG laser posterior capsulotomy. DESIGN: Comparative autopsy tissue analysis. PARTICIPANTS: A total of 5416 globes with posterior chamber intraocular lens (PC-IOLs) obtained postmortem received from Lions Eye Banks between 1988 and 2000. METHODS: Miyake-Apple posterior photographic technique. Special reference was given to the presence or absence of Nd:YAG laser posterior capsulotomy orifice on the posterior capsule of each eye. MAIN OUTCOME MEASURES: The Nd:YAG laser posterior capsulotomy rate (%) as of January 2000 was documented. In addition, the Nd:YAG laser posterior capsulotomy rate for each lens was plotted on a monthly basis for the same period, creating a computerized trend or "timeline" for each IOL style. RESULTS: Relatively high Nd:YAG laser posterior capsulotomy rates ranging from 20.3% to 33.4% were noted with four relatively older designs (high incidence of implantation between 1988 and the early 1990s). Four modern foldable IOLs manufactured from silicone and acrylic materials had significantly lower Nd:YAG laser posterior capsulotomy rates ranging from 0.9% (Alcon Acrysof) to 17.1%. The difference in Nd:YAG rates among the eight IOL designs was found to be significant (P < 0.0001, chi-square test). Comparing foldable versus rigid designs, the foldable IOLs were associated with a much lower Nd:YAG laser posterior capsulotomy rate (14.1% vs. 31.1%). CONCLUSIONS: By use of the six factors regarding surgical technique and IOL choice described in this article, we strongly believe that the overall incidence of PCO and hence the incidence of Nd:YAG laser posterior capsulotomy is now rapidly decreasing from rates as high as 50% in the 1980s to early 1990s. Surgical tools and IOLs are now available to bring these rates down to single digits. Careful application and use of these tools by surgeons can genuinely lead in the direction of virtual eradication of secondary cataract, the second most common cause of visual loss worldwide.
Cataract↗
Effect of Healon5 and 4 other viscoelastic substances on intraocular pressure and endothelium after cataract surgery.
PURPOSE: To compare the ophthalmic viscoelastic device (OVD) Healon5 (sodium hyaluronate 2.3%) with 4 other commonly used OVDs during phacoemulsification and intraocular lens implantation in terms of influence on intraocular pressure (IOP) postoperatively and endothelial cells preoperatively and postoperatively. SETTING: Department of Ophthalmology, Ruprecht-Karls-University Heidelberg, Germany. METHODS: This clinical randomized prospective study, in which patients and observer were masked, comprised 81 eyes. Seventy-four eyes (mean patient age 71.2 years +/- 7.8 [SD]) completed all preoperative and 5 postoperative examinations. The OVDs used were OcuCoat and Celoftal (hydroxypropyl methylcellulose 2.0%), Viscoat (sodium hyaluronate 3.0%-chondroitin sulfate 4.0%), Healon GV (sodium hyaluronate 1.4%), and Healon5 (sodium hyaluronate 2.3%). Intraocular pressure was measured by standard Goldmann applanation tonometry preoperatively and 4 to 6 and 24 hours and 7, 30, and 90 days postoperatively. Endothelial cell counts were done preoperatively and 90 days postoperatively using a Pro/Koester WFSCM contact endothelial microscope. Exclusion criteria were IOP greater than 21 mm Hg at the preoperative examination, age younger than 40 years, significant corneal pathology, and a history or presence of uveitis or pseudoexfoliation syndrome. RESULTS: All groups had increased IOP 4 hours postoperatively. The Healon5 group had the highest mean pressure (24.9 mm Hg) followed by the Viscoat group (23.6 mm Hg). The mean IOP in the other OVD groups was less than 22.1 mm Hg. These differences were not significant. Twenty-four hours postoperatively and at all subsequent examinations, mean IOP was below 20 mm Hg. The Healon5 group had the lowest mean endothelial cell loss (6.2%), significantly lower than in the other groups (P < .02). CONCLUSION: With all 5 OVDs, endothelial cell loss was found, with the lowest in the Healon5 group, and IOP was increased 4 to 6 hours postoperatively. After 24 hours, no significant increases in IOP were noted.
Aged↗
Clinical results of phacoemulsification with the use of Healon5 or Viscoat.
PURPOSE: To compare the ophthalmic viscosurgical devices Healon5 (viscoadaptive) and Viscoat (dispersive) regarding their overall clinical performance during phacoemulsification and posterior chamber intraocular lens (IOL) implantation as well as their influence on intraocular pressure (IOP). SETTING: Department of Ophthalmology, Ruprecht-Karls-University Heidelberg, Heidelberg, Germany. METHODS: In this prospective randomized patient- and observer-masked clinical study, the performance of Healon5 (sodium hyaluronate 2.3%) and Viscoat (sodium hyaluronate 3.0%-chondroitin sulfate 4.0%) was assessed by 3 surgeons during cataract surgery in 90 patients. Surgeons used a 5-point scale for the subjective assessment of the ease of injection, maintenance capacity during continuous curvilinear capsulorhexis, remaining capacity during phacoemulsification, facilitation of IOL implantation, removal from the eye, transparency, and overall performance throughout surgery. Intraocular pressure was measured preoperatively and 24 hours and 7 days postoperatively. Best corrected visual acuity was assessed preoperatively and 7 days postoperatively. RESULTS: Overall intraoperative product performance was assessed as good or very good in 34 of 44 patients (77%) in the Healon5 group and in 16 of 46 patients (35%) in the Viscoat group (P <.001). Retention in the anterior chamber was graded good or very good in 36 patients (82%) in the Healon5 group and in 23 (50%) in the Viscoat group (P =.001). There were no statistically significant between-group differences in mean IOP preoperatively and 24 hours postoperatively. CONCLUSIONS: Surgeons graded Healon5 better than Viscoat in overall surgical performance and retention in the anterior chamber during phacoemulsification. These data support that Healon5 adapts to each step during surgery.
Aged↗
[Postoperative opacification of posterior chamber intraocular lenses - a review].
Postoperative opacification of intraocular lenses (IOLs) is a very unpleasant complication for the ophthalmic surgeon and the patient. We report on our experiences with opacification of different foldable IOL designs and rigid poly (methyl methacrylate) (PMMA) posterior chamber lenses.1. Snowflake degeneration of PMMA IOLs: This condition is an unanticipated and surprising late postoperative finding 8 to 15 years after implantation. In our opinion, this complication is probably not related to the PMMA biomaterial itself, but rather it appears to represent a manufacturing problem that has affected a selected, albeit large number of lenses manufactured in the 1980s-mid 1990s.2. Degeneration of UV absorber material and calcium deposits within the optic of hydrophilic IOLs: Two years postoperatively degenerations of UV absorber material and calcium deposits within the optic of single piece hydrophilic acrylic lenses SC60B-OUV manufactured by MDR (Medical developmental research Inc. Clearwater FL, USA) can occur. Although the precise mechanism is not fully known, it was assumed that these opacifications are due to premature aging of the UV blocking agent incorporated in the lens biomaterial and calcification.3. Calcification on the surface of the Bausch & Lomb Hydroviewtrade mark IOLs: Twelve to 15 months postoperatively granular surface calcifications in Hydroviewtrade mark IOLs occured. The mechanism is not fully understood. According to Bausch and Lomb studies, part of the components of the packaging contained silicone, which may have come off the packaging onto the lens optic, where it then appears to be a catalyst for calcium precipitation. The manufacturer has correlated a change in packaging with the appearance of the opacification. The manufacturer now believes that this problem has been solved. However, final verification will require a careful 1 - 2 years clinical study.4. Glistenings in the hydrophobic acrylic AcrySoftrade mark IOLs: The time frame of glistenings in the AcrySoftrade mark IOLs is highly variable. It has been suggested that the occurrence of glistenings may be related to variations in the temperature of the lens just prior to and or during insertion into the eye. Formation of vacuoles may occur within the submersed acrylic polymer when there is a transient increase and then decrease in temperature during the surgical procedure. "Glistenings" may then subsequently form by ingress of anterior chamber fluid. Contrast sensitivity can been decreased in some patients, but clinically significant decrease of visual acuity has been rare.
Biocompatible Materials↗
[Millenniums update on posterior capsule opacification (PCO) scores, centration, biocompatibility and fixation of foldable intraocular lenses (IOL) - an analysis of 1,221 pseudophakic post mortem globes].
BACKGROUND: The ongoing and fast evolution of foldable IOL designs established the necessity to evaluate the different abilities of each lens style. The large IOL database (over 16,500 specimens) acquired in our laboratory, has permitted us to perform a clinico-pathological analysis on pseudophakic autopsy globes provided from sources worldwide, especially many Lions Eye banks in the United States. MATERIAL AND METHODS: We analyzed 6 foldable IOL styles commonly implanted in the United States, using one type of rigid IOL design (1-piece design rigid PMMA optics) as a comparison group. Posterior capsule opacification (PCO) score, decentration, fixation, presence or absence of a Nd:YAG laser posterior capsulotomy and area and intensity of Soemmerring's ring formation was discerned by examination under an operating microscope using the Miyake-Apple posterior photographic technique. RESULTS: The four lenses with the lowest rates ranging between 3.8 % and 21.7 % are modern designs, mostly implanted after 1992. The two lenses with the higher rates ranging between 23.1 % and 30.4 %, were all older designs, already prevalent prior to 1992. IOL fixation with both haptics in the capsular bag showed the best centration values and PCO scores. Our studies to date have shown in a preliminary fashion that the AcrySoftrade mark IOL displays the the lowest (best) biocompatibility score. CONCLUSIONS: Entering the new millenium, with evolution of modern surgical techniques and IOL designs, the incidence of the two major complications of cataract surgery, decentration and PCO are now finally diminishing.
Autopsy↗
Reliability of intraocular lens power calculation after cataract surgery in patients with relative anterior microphthalmos.
BACKGROUND: Patients with relative anterior microphthalmus (RAM) are characterized by special anatomical features (corneal diameters <11 mm, anterior chamber depth <2 mm and normal axial length) that sometimes make intraocular lens (IOL) power calculation difficult. PATIENTS AND METHODS: Seventy-five patients aged 75.6+/-10.3 years with RAM were evaluated for preoperative target refraction and postoperative refraction after cataract surgery. We used biometric formulas as modified by Haigis for IOL power calculation. RESULTS: The average IOL power implanted was 25.2+/-2.8 dptr (one-piece all-PMMA IOL; range 19-31 dptr). The preoperatively calculated target refraction was -0.71+/-1.43 dptr (range -4.3 to +2.2 dptr). The average postoperative spherical equivalent was -0.41+/-1.50 dptr (range -5.5 to +6.0 dptr). The mean difference between target and end refraction was -0.30+/-1.54 dptr Fifty-seven percent of cases did not differ by more than 1 dptr from target refraction, 81.3% by not more than 2 dptr, and 94.7% by not more than 3 dptr; only 5.3% of cases deviated by more than 3 dptr. There was no correlation of the amount of deviation between target and postoperative refraction with axial length, corneal diameter and anterior chamber depth. There was, however, a significant correlation between target refraction and amount of deviation of spherical equivalent. The largest differences were found with target refractions greater than +2 dptr. CONCLUSIONS: In spite of the special anatomical conditions in patients with RAM the biometric formulas as modified by Haigis produced reliable IOL power calculations. The best accuracy was achieved when aiming at a target refraction in the range of +/-2 dptr.
Adult↗
[Analysis of energy levels for Nd:YAG laser capsulotomy in secondary cataract].
BACKGROUND: Formation of secondary cataract is influenced by various factors, such as IOL material, IOL design, age, follow-up time and ocular and systemic diseases. It has not yet been studied whether these factors have an clinical impact on the energy used for Nd:YAG laser capsulotomy. PATIENTS AND METHODS: We examined 172 patients, aged 67.3+/-15.9 years, concerning energy levels required for Nd:YAG laser capsulotomy. We analysed the influence of age, implant duration, IOL fixation and ocular conditions on total energy and repetition rate of Nd:YAG laser capsulotomy. Sixty-nine patients (43. 7%) had no other ocular pathology (control), 24 (15.2%) glaucoma, 14 (8.9%) diabetic retinopathy, 12 (7.6%) retinitis pigmentosa, 8 (5. 1%) high myopia, 7 (4.4%) triple procedure with perforating keratoplasty. Twenty-four (15.2%) presented with various additional ocular conditions such as pseudoexfoliation syndrome. Patients had undergone cataract surgery between 1988 and 1995 with implantation of PMMA-IOLs. RESULTS: Nd:YAG laser capsulotomies were performed on average 28.2+/-17.7 months postoperatively. The average total energy used was 12.7+/-9.4 mJ. Visual acuity (Pre-YAG) was 0.3+/-0.2. In the control group there was no correlation between energy and implant duration or age (P>0.43). 26 patients required a second Nd:YAG laser capsulotomy. Patients with retinitis pigmentosa showed a significantly higher re-YAG rate than the other patient groups (P=0.00059). In eyes with sulcus fixation of the IOL, capsulotomies were performed earlier and with higher energy levels than for in-the-bag fixation. CONCLUSIONS: The different ocular conditions of the anterior and posterior segment showed a different profile for Nd:YAG laser capsulotomy energy level and Nd:YAG laser repetition rate. Sulcus fixation of an IOL resulted in earlier capsulotomies with higher energy levels.
Aged↗
Relative anterior microphthalmos: morphometric analysis and its implications for cataract surgery.
PURPOSE: To evaluate morphometric data and risk factors for complications of cataract surgery in patients with relative anterior microphthalmos (RAM). DESIGN: Retrospective, comparative study (Part I) and matched pairs analysis with controls (Part II). PARTICIPANTS: Sixty-two patients with RAM who underwent cataract surgery at the Department of Ophthalmology, Ruprecht-Karls-University of Heidelberg, Germany, between 1989 and 1997. RAM is defined as eyes with horizontal corneal diameters </=11 mm, axial length of >20 mm, and no other morphologic malformation. MAIN OUTCOME MEASURES: Part I: Patients were examined preoperatively for anterior chamber (AC) depth, lens thickness, total axial length, and refraction. Associated ocular pathologic conditions (such as glaucoma or previous surgical interventions) were recorded. Part II: A matched pairs analysis concerning the anatomic features was performed with a group of 17 patients with RAM and 17 patients (controls) that matched the RAM group in terms of axial length, age, and gender but showed corneal diameters >11 mm. RESULTS: Part I: Anatomic parameters in RAM showed an average corneal diameter of 10.7 +/- 0.34 mm, AC depth of 2.20 +/- 0.49 mm, and average lens thickness of 5. 05 +/- 0.45 mm. Fifty-five percent of the patients had myopic refraction. There was a high incidence of glaucoma (77.4%), cornea guttata (45.2%), and pseudoexfoliation syndrome (16.1%) in the RAM group. Sixty percent of patients had undergone previous glaucoma surgery. After cataract surgery, 51.2% of patients achieved a visual acuity of >20/40 and 69.8% of >20/50. Temporary corneal edema (54. 8%) and ciliolenticular block (11.6%) were the most important complications after cataract surgery. Part II: Matched pairs analysis showed significant differences between RAM and controls in terms of AC depth (P =0.029) but no difference in lens thickness (P = 0.12). CONCLUSIONS: Relative anterior microphthalmos can be characterized in terms of morphometric data as eyes with corneal diameters </=11 mm and AC depths of 2 mm. The small anterior segment, especially the shallow anterior chamber, is responsible for the high incidence of glaucoma and postoperative complications after cataract surgery. Identifying these patients before surgery helps the cataract surgeon to be prepared for potential problems.
Aged↗
Keratoconus evaluation using the Orbscan Topography System.
PURPOSE: To evaluate corneal topography in a series of keratoconus patients using the Orbscan Topography System. SETTING: Department of Ophthalmology, Ruprecht-Karls-University of Heidelberg, Heidelberg, Germany. METHODS: Seventy-one eyes of 38 patients with keratoconus were evaluated. Quantitative topographic parameters were analyzed with special reference to the central point of the cornea, the apex (the point with maximum reading on the anterior elevation best-fit sphere map), and the thinnest point. Evaluation included location, elevation (compared to a best-fit sphere), pachymetry, tangential curvature, and composite curvature. The mirror-image symmetry between the right and left eyes of a patient was also investigated. RESULTS: Mean patient age was 31.2 years +/- 12.2 (SD). Thirty-three patients (86.8%) had bilateral keratoconus and 5 (13.2%), unilateral keratoconus. Most cones (68/71) were located in the inferior temporal quadrant; 3 were above the horizontal meridian. Mean distance between the apex and the thinnest point was 0.917 +/- 0.729 mm (P < .001). The correlations between apex elevation and apex composite curvature and apex tangential curvature were high (r = 0.94 and r = 0.91, respectively; P < .001). In right and left eyes, there was a correlation between the apex and the thinnest point semi-meridians (r = 0.47 and r = 0.65, respectively; P < .05) but not between the radii of the apex and the thinnest point (r = 0.21 and r = 0.24, respectively). CONCLUSIONS: The Orbscan system can provide useful and accurate information in defining the morphology of keratoconus and detecting subtle topographic changes present in early keratoconus. It may also improve the results of contact lens fitting and surgical management.
Adolescent↗
[Cataract surgery in 79 patients with relative anterior microphthalmus (RAM): a review of anatomy, associated pathology and complications].
BACKGROUND: Naumann has coined the term relative anterior microphthalmus (RAM) for eyes with a dysproportional small anterior segment but no further malformation. Those eyes are characterized by corneal diameters of < 11 mm and total axial length of > 20 mm. PATIENTS AND METHODS: To evaluate and define morphometrical data and risk factors for cataract surgery in patients with relative anterior microphthalmus (RAM) 112 cataract operations of 79 patients with RAM were analysed. Associated ocular pathology (such as glaucoma, previous surgical interventions, etc.) and complications of cataract surgery were recorded. RESULTS: Average corneal diameter was 10.7 +/- 0.34 mm, AC-depth was 2.20 +/- 0.49 and average lens thickness 5.05 +/- 0.45 mm. Fifty five percent of the patient revealed myopic refraction. There was a high incidence of glaucoma (77%), cornea guttata (46.6%) and Pseudoexfoliation syndrome (16%) in the RAM-group. Sixty percent of patients previously underwent glaucoma surgery. After cataract surgery 51.2% of patients achieved a visual acuity of > 0.5; 69.8% > 0.4. The IOP was preoperatively 16.5 +/- 5.8 mm Hg (with 1.3 +/- 1.4 antiglaucomatous drugs). Postoperatively IOP dropped significantly to 13.6 +/- 3.2 mm Hg (with significant reduction of treatment (0.6 +/- 1.0) (p < 0.01). The anterior chamber depth deepened from 2.42 +/- 0.47 mm to 3.33 +/- 0.72 mm. CONCLUSIONS: The special anatomical situation in RAM is responsible for the high incidence of glaucoma and postoperative complications after cataract surgery. Cataract surgery helps not only to restore vision but also facilitates handling and regulation of intraocular pressure.
Aged↗
Update on fixation of rigid and foldable posterior chamber intraocular lenses. Part I: Elimination of fixation-induced decentration to achieve precise optical correction and visual rehabilitation.
PURPOSE: Realizing that precise posterior chamber intraocular lens (PC-IOL) centration is needed to consistently achieve good optical results and visual rehabilitation after modern cataract surgery, the authors assessed the status and success rate of lens haptic fixation and its correlation with lens optic centration-decentration in a large series of eyes with PC-IOLs obtained postmortem. DESIGN: Prospective analysis of pseudophakic eyes obtained postmortem. PARTICIPANTS: A total of 3493 human eyes obtained postmortem, the largest database of such specimens available to date. METHODS: Miyake-Apple posterior photographic technique. MAIN OUTCOME MEASURES: The amount of decentration of rigid PC-IOLs and small-incision foldable PC-IOLs was analyzed, and the results were correlated with the type of fixation that had been achieved in each case. RESULTS: Determination of mean values revealed that capsular bag fixation was achieved in 52.05% of eyes, asymmetric bag-sulcus fixation in 34.21 % of eyes, and sulcus-sulcus fixation in 13.74% of eyes. Asymmetrically fixed lenses consistently showed significant decentration. During the past 5 years (1993-98), the overall rate of in-the-bag fixation increased to 59.2%; by 1998 it had increased to 64%. Most significantly, success in achieving bag-bag fixation of foldable IOLs implanted in association with modern capsular surgery with small incisions has surged to 90% over the past 4 years. CONCLUSIONS: The authors found a direct correlation of decentration in eyes with asymmetric fixation, and the results underscore the need for careful in-the-bag haptic placement. Although few surgeons today would dispute the goal to implanting haptics in the capsular bag, these findings show that the overall success rate over the years has, while improving, remained surprisingly low. The overall success rate of about 60% seen with all lens designs is probably as good as can be expected with classic large-incision extracapsular techniques. However, and most important and encouraging, the success rate of haptic fixation in cases with foldable lenses has improved dramatically during the past 4 years (up to the 90% range). This coincides with the present emphasis on modern capsular surgery and small-incision techniques used to insert these lenses.
Acrylic Resins↗