Optic disc shape, corneal astigmatism, and amblyopia

OBJECTIVE: The cornea and the optic disc form the anteroposterior opening of the sclera. This study evaluated whether an abnormal shape of the optic disc is associated with an abnormal configuration of the cornea measured as corneal astigmatism. DESIGN: The study design was a cross-sectional one. PARTICIPANTS: The study included 882 subjects (430 women, 452 men) with a mean age of 45.9 +/- 13.6 years (mean +/- standard deviation; range, 8-87 years) and a mean refractive error of -1.09 +/- 2.76 diopters (range, -21.0 diopters to +7.0 diopters). INTERVENTION: Corneal astigmatism was determined by keratometry, and the optic disc was analyzed morphometrically by planimetric evaluation of optic disc photographs. MAIN OUTCOME MEASURES: Corneal astigmatism, ratio of minimal-to-maximal disc diameter, and optic disc form factor were measured. RESULTS: The amount of corneal astigmatism was significantly (P < 0.001) correlated with an increasingly elongated optic disc shape. Corneal astigmatism was significantly (P < 0.01) higher in eyes with tilted discs. It was significantly (P = 0.006) smaller in eyes with an almost circular disc shape. Amblyopia was significantly (P < 0.05) associated with an elongated optic disc shape and high corneal astigmatism. The axis of corneal astigmatism was correlated with the orientation of the longest disc diameter. The optic disc was significantly (P < 0.05; chi-square test) more often horizontally oval in eyes with a steeper horizontal corneal meridian than in eyes with a steeper vertical corneal meridian. Correspondingly, the disc was significantly (P < 0.05) more often vertically oval in eyes with a steeper vertical corneal meridian than in eyes with a steeper horizontal corneal meridian. CONCLUSIONS: An abnormal optic disc shape is significantly correlated with corneal astigmatism. Especially in young children, if an abnormal optic disc shape is found on routine ophthalmoscopy, refractometry should be performed to rule out corneal astigmatism and to prevent amblyopia. The direction of the longest optic disc diameter can indicate the axis of corneal astigmatism.     

Scaffolding: a broader view

PURPOSE: To define measures of assessing success and subsequent ways to improve excimer laser treatment of astigmatism. METHODS: We studied 97 eyes of 79 patients, followed for 12 months, that underwent photorefractive keratectomy (PRK) for myopia and astigmatism with a VISX 20/20 excimer laser. Preoperative spherical equivalent refraction at the corneal plane was between -1.00 and -15.00 D. Mean preoperative refractive astigmatism at the spectacle plan was -2.17 +/- 1.05 D (range, -1.25 to -6.00 D), which is -1.81 +/- 0.86 D (range -1.04 to -4.97 D) when calculated at the corneal plane. All patients were examined before and after surgery; examination included refraction, keratometry, and topography measurement. RESULTS: The success in treatment of astigmatism appeared measurably less than the treatment of sphere when analogous indices were used for assessment. Success in astigmatism surgery improved, as measured by all parameters, after an additional 20% was applied to astigmatism treatment magnitude indicated by the VISX computer algorithm. The sequential modes of treatment undercorrected astigmatism magnitude to a greater extent than elliptical, but equivalent success rates were present in view of the greater astigmatic changes attempted using the sequential mode. The elliptical mode tended to produce a greater undercorrection of associated sphere (p = 0.313). Results measured by refraction showed a larger change than those measured by topography and keratometry. CONCLUSION: During PRK with the VISX 20/20 laser, adjustment for undercorrection of astigmatism treatment achieves a fuller correction of astigmatism. When measuring astigmatic changes, results are different when comparing refractive astigmatism changes with corneal astigmatism changes measured by keratometry and topography.     

Differences in performance of screening instruments for problem drinking among blacks, whites and Hispanics in an emergency room population

BACKGROUND: As new methods for corneal curvature measurement have evolved, users of videokeratscopes need to know the practical limitations of these instruments. We assessed agreement between keratometry and videokeratography in measuring highly astigmatic corneas. METHODS: Two independent examiners made three keratometric and videokeratographic measurements on each of 33 corneas after penetrating keratoplasty. The non-orthogonal keratometric readings obtained with a Zeiss 10 SL/O keratometer (Carl Zeiss Ltd.) were compared to the non-orthogonal simK readings (maxK, minK) calculated by the algorithms of a TMS-1 videokeratoscope (Tomey). Measurement agreement was evaluated for steep and flat meridian power and location, and astigmatism magnitude (D). RESULTS: A systematic bias of the TMS-1 in measuring steeper than keratometry for the steep meridian was demonstrated (95% confidence interval: -0.34 to -1.20 D). The limits of agreement (d - 2SD to d + 2SD) between the two instruments were found to be unacceptable for clinical purposes in measuring steep meridian power (-3.17 to +1.63 D), flat meridian power (-4.92 to +4.48 D) and astigmatism magnitude (-5.84 to +4.87 D). Clinically acceptable differences were observed in identification of steep and flat meridian location. CONCLUSIONS: The Zeiss 10 SL/O keratometer and the TMS-1 videokeratoscope showed poor measurement agreement for irregular corneal surfaces, despite the good correlation previously shown between keratometry and videokeratography in calibrated spheres and regular corneas. The TMS-1 showed a systematic bias, measuring a greater power in the steeper meridian than the Zeiss 10 SL/O keratometer. It is suggested that the two instruments cannot be used interchangeably in comparing the curvature of corneas after penetrating keratoplasty.     

Alzheimer''s disease: the advent of effective therapy

PURPOSE: To investigate the astigmatic keratotomy effect of a modified single-hinge cataract incision. SETTING: Department of Ophthalmology, San Juan de Dios Hospital, Tenerife, Spain. METHODS: This prospective study evaluated the astigmatic changes resulting from preincision grooves of less than 40, 45, and 55 degrees in arc length used with a single-hinge, self-sealing cataract incision in 144 eyes that had against-the-rule corneal astigmatism preoperatively. The intended 90% depth preincision was centered on the steep meridian and lengthened according to the amount of preoperative astigmatism. Outcome measurements were obtained by calculating the surgically induced astigmatism vectors and the postoperative keratometry changes 1 day, 1 week, and 1, 3, and 6 months after surgery. RESULTS: Three months postoperatively, astigmatism decreased by 0.03, 0.30, and 0.68 diopter in the less than 40, 45, and 55 degree incision length groups, respectively. The differences between the 45 and 55 degree groups and the less than 40 degree group was statistically significant (P < .05). Similar results were observed 6 months after surgery. CONCLUSION: The astigmatic preincision modification produced statistically significant increasing reductions in preoperative astigmatism according to preincision length.     

Pneumatic displacement of subretinal hemorrhage without tissue plasminogen activator

PURPOSE: To analyze the results of excimer laser phototherapeutic keratectomy (PTK) combined with simple excision in recurrent pterygium to minimize the recurrence rate and obtain a smooth corneal surface. SETTING: Veni Vidi Eye Health Centre, Istanbul, Turkey. METHODS: Combined pterygium excision and excimer laser PTK was performed in 22 eyes with recurrent pterygium (22 patients). Both spot and scan modes of the Meditec MEL 60 excimer laser were used to produce a wide ablation layer (depth 40 to 80 microns). RESULTS: During the mean follow-up of 16.5 months (range 6 to 27 months), visual acuity, refraction, slitlamp, and corneal topography examinations were recorded. Pterygium recurred in only 1 eye (4.5%). Postoperative visual acuity improved in 15 eyes (68.2%). Keratometric readings were not accurately measured preoperatively because of corneal surface irregularities but could be easily taken after the surgery. Corneal astigmatism ranged from 0 to 2.00 diopters (D) (mean 1.23 D). Three months after surgery, no haze persisted in any eye. No significant intraoperative or postoperative complication was detected. CONCLUSIONS: Excimer laser PTK appears to simplify pterygium surgery because a superficial keratectomy is sufficient to remove pterygium. The excimer laser can be used to ablate the visible residual tissues and smooth the corneal surface, resulting in good postoperative refraction and visual acuity. Consequently, this procedure seems to be effective and safe.     

Arcuate keratotomy to treat corneal astigmatism after cataract surgery: a prospective evaluation of predictability and effectiveness

OBJECTIVE: Although several nomograms are available for the incisional keratotomy to correct naturally occurring astigmatism, astigmatic keratotomy in eyes after cataract surgery has not been well analyzed. The predictability and effectiveness of arcuate keratotomy in pseudophakic eyes were studied. DESIGN: A prospective, multicenter study. PARTICIPANTS: One hundred four eyes of 86 patients with residual corneal astigmatism of 1.5 diopters (D) or more after cataract surgery were examined. INTERVENTION: Arcuate keratotomy was performed in nine centers by nine surgeons. MAIN OUTCOME MEASURES: The amount of astigmatic correction was calculated using the vector analysis of preoperative and 6-month postoperative refractive cylinder results. RESULTS: Multiple regression analysis showed that optical zone size, number of incisions, and incision length had significant correlations with the amount of astigmatic correction. The regression equation was expressed as effects = (-0.643 x optical zone size) + (0.998 x incision number) + (0.057 x incision length) + 2.356. The parameter of predictability (r2: 35%) was lower than that reported for congenital astigmatism (48 to approximately 56%). A new nomogram was derived based on the multiple regression equation. CONCLUSIONS: Astigmatic keratotomy in pseudophakic eyes is less predictable than that in eyes with idiopathic astigmatism, but the procedure is sufficiently effective in reducing the residual astigmatism after cataract surgery. Individual nomograms are necessary for astigmatic keratotomy in eyes with naturally occurring and postsurgical astigmatism.     

Treatment of irregular astigmatism

PURPOSE: To treat irregular astigmatism by applying separate appropriate treatments in each of the two distinct hemidivisions of the cornea. SETTING: Cheltenham Eye Centre, Melbourne, Australia. METHODS: Two general surgical strategies are presented. The first applies the principles of optimization separately to each corneal hemidivision to achieve the maximum reduction in astigmatism when measured topographically and refractively. The second is for targeting symmetrical orthogonal topographic goals for each semimeridian to create the regular state in differing ways. These are performed in one of the following ways: without changing refractive astigmatism; by reducing the associated ocular residual astigmatism; by shifting the less favorably placed topography semimeridian to the other more favorably located one; by shifting both topographic semimeridians to more favorably located sites. This is an alternative when a potential improvement in the best corrected visual acuity is sought and the maximum reduction of astigmatism is not the priority. RESULTS: The calculated treatments necessary to achieve various improved astigmatic states, together with each of their respective separate refractive astigmatism targets, are presented. A single refractive astigmatism value for the entire cornea is also calculated by vector summation. CONCLUSION: Consideration of each of the two distinct hemidivisions of the eye enables improved treatment of irregular astigmatism, potentially resulting in improved visual outcomes.     

Corneal astigmatism after clear corneal and corneoscleral incisions for cataract surgery

PURPOSE: To compare the astigmatism induced by clear corneal incisions (CCIs) and corneoscleral tunnel incisions (CSIs) for cataract surgery over 6 months. SETTING: Rotterdam Eye Hospital, rotterdam, The Netherlands. METHODS: Thirty-five patients having phacoemulsification were recruited prospectively; 15 had CCIs and 20, CSIs. Corneal topography was performed by computerized videokeratoscopy preoperatively and 6 months postoperatively. The change in keratometric astigmatism was calculated using the absolute magnitude and vector analysis methods. RESULTS: There was no significant difference between the change in astigmatism produced by the two incisions (Student's t-test). CONCLUSION: The CCI for cataract surgery did not produce significantly greater astigmatism than the CSI. Concern over CCIs having a greater risk of increasing corneal astigmatism is unfounded and does not justify withholding the technique from patients it could benefit.     

Computerized topography of selective versus all-suture release to manage high astigmatism after cataract surgery

PURPOSE: To compare the efficacy of selective suture release (SSR) with all-suture release (ASR) in controlling corneal astigmatism after cataract surgery. SETTING: Sight Saver's Cornea Training Centre, L.V. Prasad Eye Institute, Hyderabad, India. METHODS: This prospective, randomized study evaluated the effect on astigmatism of two techniques of suture release in 30 patients with more than 3.00 diopters (D) of corneal astigmatism after cataract surgery. All patients had interrupted sutures with well-healed wounds. Fifteen patients had ASR irrespective of the location of the steep meridian. In the other 15, only the suture located in the steep meridian was selectively released. The pattern of decay of astigmatism after suture release was studied using computerized videokeratography. RESULTS: Mean pretreatment corneal cylinder was 6.30 D +/- 2.72 (SD) in the ASR group and 6.95 +/- 1.67 D in the SSR group. In the ASR group, corneal cylinder dropped to 3.70 +/- 1.15 D immediately after suture release and further decreased to 1.82 +/- 0.66 D at 1 week (P < .001). In the SSR group, astigmatism swung erratically to the adjoining sutures and decreased unpredictably at an average of 1.32 +/- 2.00 D with each suture release. CONCLUSION: The ASR technique was more predictable and less cumbersome than the SSR method.     

Further study of hepatitis C virus RNA detection in formalin-fixed, paraffin-embedded liver tissues by ligation-dependent polymerase chain reaction

AIM: Refractive cataract surgery using corneal incisions is aiming at neutralization of preoperative astigmatism. PATIENTS AND METHODS: 61 patients with preoperative astigmatism of 2.25 +/- 0.98 were included in the treatment. A self-sealing corneal tunnel incision measuring 4.0 to 4.1 mm in external diameter and 6.5 to 7.0 mm in internal diameter (stretch incision) was performed on the steeper axis. After capsulorhexis and phacoemulsification a 5 mm PMMA lens was implanted without suturing. Keratometry and corneal topography were performed preoperatively, 3 days and 1 year respectively following surgery. The statistical analysis was based on the Wilcoxon signed ranks test. RESULTS: Surgical induced astigmatism (IA) following superior incisions in cases of astigmatism with the rule (n = 29) amounted to 1.93 +/- 0.97, while lateral incisions in cases of astigmatism against the rule (n = 29) led to an IA of 1.35 +/- 0.73. Axial shifts by more than 30 degrees were 23% following superior incisions and 17%, after lateral incisions. We observed. astigmatic reduction of 1.3 D after superior incisions and 0.7 D following lateral incisions. CONCLUSION: By 4 mm corneal cataract incisions on the steeper axis a high preoperative astigmatism can be reduced significantly without additional keratotomies.     

Intravenous pamidronate treatment in osteogenesis imperfecta

BACKGROUND: Astigmatic keratotomy is used conventionally to correct moderate surgical astigmatism. However, cases with very high surgical astigmatism due to wound compression can show a dramatic response to relaxing keratotomies made in the steeper meridian. The effect obtained cannot be predicted pre-operatively by using standard nomograms. METHODS: Coupled arcuate keratotomies combined with corneal valvular incisions were performed in a case of high astigmatism post-cataract surgery. RESULTS/CONCLUSION: Coupled arcuate keratotomies were combined with a corneal valvular incision enabled a surgical correction of nearly 9 D of astigmatism.     

Glutathione peroxidase activity and glutathione concentration in genetically dystrophic mice

The case of a 6-year-old boy is reported who was delivered out of a frontal position by application of the vacuum cup to the left part of the forehead. His left eye exhibits a pronounced somewhat irregular astigmatism. There are some vertical descemet tears. Because of the application of the vacuum pump close to the left bulbus, an increase of the tissue tension and consequently a deformation of the bulbus occurred by the vacuum in the bulbar region. The described lesions parallel the vertical descement tears which occur in forceps-delivery. Owing to the greater horizontal corneal diameter, a more pronounced extension of the cornea in the horizontal meridian occurs, which would explain the vertical course of the descemet tears. The obstetric contraindication for the application of the vacuum extraction in case of a frontal or facial position of the fetus is justified also from the ophthalmological point of view because of the risk of occurrence of irreversible corneal lesions.     

Different suturing techniques variously affect the regularity of postkeratoplasty astigmatism

OBJECTIVE: This study aimed to determine the effect of various suturing techniques on the regularity of postkeratoplasty astigmatism. DESIGN: A prospective clinical trial. PARTICIPANTS: Sixty-two consecutive patients undergoing penetrating keratoplasty by the same surgeon (MB) participated. INTERVENTION: Each patient was assigned to one of four groups according to the suturing technique used (a = 16 interrupted 10-0 nylon sutures; b = 2 running 10-0 nylon sutures, each with 8 bites; c = 2 running 10-0 nylon sutures, each with 12 bites; d = 2 running 10-0 nylon sutures, each with 16 bites). This was the only parameter permitted to be changed in the standard keratoplasty procedure used for all cases. Corneal topography was performed 1, 3, and 6 months after surgery. The astigmatic patterns seen on the corneal maps then were classified into regular (symmetric or asymmetric bowtie patterns) or irregular (distorted bowtie, multiaxial, or other patterns). MAIN OUTCOME MEASURES: Regularity of postkeratoplasty corneal astigmatism was measured. RESULTS: At all postoperative examination times, the percentage of irregular astigmatic patterns was highest in group a and lowest in group d (chi-square test: P < 0.005). Groups b and c showed intermediate values. The entity of the astigmatic error as measured by the simulated K-readings of the topographic maps did not differ significantly in the four groups. CONCLUSIONS: A suturing technique using 2 running sutures with 16 bites each can minimize irregular postkeratoplasty astigmatism as long as sutures are in place, when compared with interrupted sutures or double-running sutures of less than 16 bites.     

Corneal shape changes after scleral buckling surgery

PURPOSE: A prospective study was conducted to investigate the corneal shape changes due to scleral buckling surgery. These changes were analyzed based on the type of buckling procedures performed. METHODS: A total of 89 eyes from 88 patients were stratified into four groups based on the type of buckling procedures used, including:group A, local buckling; group B, encircling; group C, encircling with vitrectomy; and group D, encircling with additional segmental buckling. These eyes underwent keratometry and videokeratography examinations before surgery as well as at 1, 3, and 6 months after surgery. RESULTS: No statistical significance was observed in the amounts of the induced corneal astigmatism and the refractive cylinder among the four groups. After local or segmental buckling (groups A and D), corneal steepening, which corresponded to the buckle, occurred at a high incidence. After encircling (groups B and C), either peripheral corneal flattening with focal central steepening or flattening on one side with coupled steepening on the opposite side was observed. Such corneal changes persisted for up to 6 months in an irregular and asymmetric configuration. CONCLUSIONS: All four types of circumferential scleral buckling surgery were found to produce prolonged irregular and asymmetric corneal shape changes, whereas the patterns of the changes differed depending on the buckling procedures used.     

Photorefractive keratectomy for astigmatism greater than -2.00 diopters in eyes with low, high, or extreme myopia

PURPOSE: To assess the efficacy of excimer laser photorefractive astigmatic keratectomy (PARK) in correcting astigmatism of more than -2.00 diopters (D) in eyes with low, high, and extreme myopia. SETTING: Pusan National University Hospital, Pusan, Korea. METHODS: Eighty-five patients (110 eyes) whose spherical error ranged from -3.00 to -13.00 D and cylinder ranged from -2.00 to -5.50 D had PARK with a VISX Twenty-Twenty excimer laser; follow-up was 6 months. All cases of myopic astigmatism were treated using the elliptical method and multizone ablation technique. Eyes were divided into 3 groups: low myopia, less than 6.00 D (n = 47); high myopia, from 6.25 to 10.00 D (n = 43); extreme myopia, over 10.25 D (n = 20). Alpins vector analysis was used to calculate the astigmatic change. RESULTS: By vector analysis, the success rate of astigmatic correction was more predictable in the low and high myopia groups than in the extreme myopia group (P < .05). There was little improvement in astigmatism in the extreme myopia group. CONCLUSION: Using PARK to correct astigmatism greater than -2.00 D in eyes with myopia less than -10.00 D tended to result in undercorrection; astigmatic correction in eyes with myopia over 10.25 D was minimal.     

Glutamatergic regulation of [3H]-noradrenaline release in the medulla oblongata of normotensive and spontaneously hypertensive rats

Using a modification of vector analysis for calculating surgically induced astigmatism, we describe a simple method that divides the induced cylinder into two orthogonal components. This decomposition allows with-the-rule and against-the-rule astigmatic changes to be calculated for individual case analysis, as well as for statistical analysis of aggregate data. Because it is based on the true induced cylinder, as determined by optical principles, this method overcomes some of the problems associated with earlier methods of evaluating surgically induced astigmatism.     

Two-incision radial keratotomy for low myopia with astigmatism

PURPOSE: To evaluate the effectiveness of two-incision radial keratotomy (RK) in correcting low-magnitude refractive myopic astigmatism. SETTING: Two clinical study sites, one in St. Louis, Missouri, USA, the other in Caracas, Venezuela. METHODS: Fifty-seven eyes of 43 patients with low-magnitude myopic astigmatism had two-incision RK at one of two clinical study sites. In the initial phase of this series, 10 eyes with amblyopia at the 20/30 level had surgery at one center. Refractive keratotomy was performed with the radial incision placed in the plus cylinder axis of refraction. This axis was verified as the meridian of greatest corneal curvature by standard keratometry and computer-assisted corneal topographic analysis. Two eyes received a second operation (enhancement). RESULTS: Mean follow-up was 11.1 months (range 6 to 12 months). Mean preoperative and postoperative myopic spherical equivalent measured -1.42 diopters (D) +/- 0.51 (SD) and -0.14 +/- 0.39 D, respectively; the mean reduction was 1.28 +/- 0.59 D (P = .0001). Mean preoperative and postoperative refractive astigmatism was 1.41 +/- 0.45 D and 0.48 +/- 0.33 D, respectively (P = .0001). Mean preoperative and postoperative keratometric astigmatism was 1.26 +/- 0.54 D and 0.31 +/- 0.35 D, respectively, a mean reduction of 0.95 D (P = .0001). The surgical meridian was flattened by an average of 2.06 D by keratometry and the orthogonal meridian, by an average of 1.10 D. Preoperative uncorrected visual acuity (UCVA) was 20/40 or better in five (9%) eyes (range counting fingers to 20/40). Postoperative UCVA acuity was 20/40 or better in all eyes (mean acuity 20/25). In the nonamblyopic subgroup mean postoperative UCVA was 20/24. CONCLUSIONS: A limited number of radial incisions placed in the topographically confirmed axis of greatest curvature are effective in the treatment of low-magnitude myopic astigmatism.     

Corneal topographic changes after frown and straight sclerocorneal incisions

PURPOSE: To compare the corneal topographic changes following cataract surgery with two types of sclerocorneal tunnel incisions for implantation of 6.0 mm optic poly(methyl methacrylate) intraocular lenses. SETTING: University Eye Hospital, Vienna, Austria. METHODS: This prospective, unmasked, and unrandomized study comprised 48 otherwise healthy eyes scheduled for cataract surgery. A 4.5 mm sutureless frown incision was made in 22 eyes and a 6.0 mm straight sclerocorneal incision with a horizontal 10-0 nylon infinity suture in 26 eyes. Preoperatively and 1 week and 1 and 3 months postoperatively, corneal topography was recorded by the TMS-1 computer-assisted videokeratoscope (Computed Anatomy, Inc.). The data were evaluated by batch-by-batch analyses of the paired differences between the records. The significance of topographic changes was calculated by paired Wilcoxon tests; group comparisons were made using Wilcoxon tests. RESULTS: In both groups, horizontal steepening and lower corneal flattening were consistently 0.4 diopter (D). Upper peripheral corneal flattening at 1 week and 1 and 3 months postoperatively was 0.7, 0.7, and 0.7 D, respectively, in the straight-incision group and 0.7, 0.4, and 0.3 D, respectively, in the frown-incision group. Vertical flattening and horizontal steepening were significant in both groups (P < .01). Group comparisons revealed significant differences in only 15 of 225 areas (P < .05). CONCLUSION: There were no major differences between the two incision groups in surgically induced topographic changes.     

Topography after repair of full-thickness corneal laceration

PURPOSE: To characterize corneal topography after repair of full-thickness corneal laceration. SETTING: Ophthalmic emergency room serving as a trauma referral center. METHODS: Twenty-two eyes with full-thickness corneal lacerations were prospectively studied after standardized surgical repair. Computerized videokeratography was done 2 and 14 weeks after surgery, with the latter measurement corresponding to 6 to 8 weeks after all sutures were removed. Fellow uninjured eyes served as the control group. RESULTS: Twenty eyes (91%) had a significant reduction in topographic distortion after suture removal. Mean corneal astigmatism, measured by simulated keratometry, was 10.70 diopters (D) +/- 5.90 D (SD) with sutures in place and 2.25 +/- 4.90 D after their removal (P < .005). Eighteen patients (82%) had 2.00 D or less of corneal astigmatism 6 to 8 weeks after all sutures were removed. The final distribution of topographic patterns was bow tie (50%), spherical/oval (36%), and irregular (14%). There was no significant correlation between laceration configuration (curvilinear, jagged, branched wound margins) and final topography. Lacerations that passed within 2.0 mm of the line of sight, however, were significantly more likely to have more than 2.00 D of final astigmatism. Mean central corneal power was 42.40 +/- 3.20 D in the injured eyes and 42.40 +/- 2.40 D in the uninjured fellow eyes. CONCLUSION: Although high astigmatism is frequently produced by corneal sutures used to repair full-thickness lacerations, the cornea has a substantial topographic memory that results in a marked normalization of contour after suture removal.     

Peripheral radial incisions to treat inferior contact lens edge lift after penetrating keratoplasty for keratoconus

A patient with marked corneal astigmatism and inferior contact edge lift after penetrating keratoplasty for keratoconus had corneal relaxing incisions (CRIs) on the donor button and radial incisions on the host cornea. Results were evaluated by computerized videokeratography and by refitting the contact lens. Two pairs of CRIs decreased astigmatism from 11.00 to 4.25 diopters but did not alleviate the contact lens edge lift, which was caused by excessive steepness in the keratoconic host cornea. After 6 radial incisions were made to flatten the inferior host cornea, the peripheral cornea flattened and the patient was successfully refitted with a contact lens.