Astigmatism following retinal detachment surgery

Incidence of Clinically Significant Aniseikonia Following Encircling Scleral Buckle Surgery: An Evaluation of Refractive and Axial Length Changes Requiring Intervention

To evaluate the incidence of symptomatic anisometropia and aniseikonia requiring intervention following surgery with combined pars plana vitrectomy (PPV) and broad 276 style encircling scleral buckle (ESB) for the repair of rhegmatogenous retinal detachments (RRD) and to report axial length (AL) and keratometry changes, a retrospective review of consecutive RRD patients treated with combined PPV and ESB between June 2016 until September 2019 was performed. All patients with symptomatic optically induced aniseikonia requiring additional interventions or surgical procedures including clear lens exchanges, secondary intraocular lens implants or contact lenses were documented. Keratometry and AL measurements were recorded for each eye and changes calculated. In total, 100 patients underwent combined PPV, ESB and endotamponade with mean age of 59.47 years (SD 11.49). AL was significantly increased (25.39 mm [SD 1.27] to 26.54 mm [SD 1.16], p = 0.0001), with a mean change of 1.15 mm (SD 0.67). Mean corneal astigmatism increased by –0.95 D (SD 0.51) in control eyes preoperatively and –1.33 (SD 0.87) postoperatively (p = 0.03). Over half of phakic patients (39/61; 64%) developed a visually significant cataract, subsequently undergoing surgery. Six of 100 patients developed symptomatic anisometropia with aniseikonia postoperatively (6%). Four proceeded with clear lens exchange despite absence of visually significant cataract (4%). Two of these initially trialled contact lenses (2%). One was intolerant, while the other decided to proceed with clear lens exchange for convenience. Only one patient (1%), being pseudophakic in both eyes, had persistent anisometropia/aniseikonia. AL and keratometry changes induced by encirclement with broad solid silicone rubber buckles are acceptable and similar to those reported previously using narrow encircling components, being unlikely to induce troublesome symptomatic anisometropia/aniseikonia. Many patients are phakic and develop visually significant cataracts, allowing correction of changes induced with the aim of visual restoration. A minority require more prolonged methods of visual rehabilitation, such as contact lens wear or clear lens exchanges. Caution and appropriate consent should be made in patients that are pseudophakic in both eyes at presentation.

Corneal Biomechanical Response Alteration After Scleral Buckling Surgery for Rhegmatogenous Retinal Detachment

PURPOSE

To compare the corneal biomechanics of eyes that underwent scleral buckle (SB) for rhegmatogenous retinal detachment (RRD) with those of fellow eyes (fellow eyes) and to further investigate the effects of SB on intraocular pressure (IOP) values.

DESIGN

Retrospective, fellow-eye matched cohort study.

METHODS

A total of 18 consecutive patients (11 males and 7 females) treated with SB for RRD in 1 eye were enrolled. Goldmann applanation tonometry was used to measure IOP. Biomechanical properties of the cornea were investigated by using the Ocular Response Analyzer (ORA) (Reichert Instruments) for the calculation of corneal resistant factor (CRF), corneal hysteresis, Goldmann-correlated IOP, and corneal-compensated IOP. Customized software was used for analysis of the ORA infrared and pressure signals, and a significance threshold was set to a P value of .05.

RESULTS

Operated eyes (OEs) showed significantly lower values of corneal hysteresis and CRF than fellow eyes (9.0 ± 1.8 vs 10.1 ± 1.8 mm Hg, respectively; P < .001; 10.0 ± 2.2 vs 10.9 ± 2.2 mm Hg; P < .001). GAT was significantly lower than corneal-compensated IOP in OEs (18.1 ± 4.9 vs 19.8 ± 4.8 mm Hg, respectively; P = .022) but not in fellow eyes. The second applanation event (A2) took place earlier in time, and the cornea was moving faster during A2 in the OEs than in the fellow eyes.

CONCLUSIONS

SB for the treatment of RRD affects corneal biomechanical response, likely due to a less compliant sclera that limits corneal motion and reduces energy dissipation, reflected in a lower corneal hysteresis. This has potentially meaningful clinical implications as the accuracy of the measurement of IOP values may be affected in these eyes.

Vitrectomy with scleral buckling versus with inferior retinectomy in treating primary rhegmatogenous retinal detachment with PVR and inferior breaks

PURPOSE

To evaluate anatomic and functional outcomes of patients treated with pars plana vitrectomy (PPV) with scleral buckling versus PPV with inferior retinectomy for treatment of cases of primary rhegmatogenous retinal detachment (RRD) associated with proliferative vitreoretinopathy (PVR) and inferior retinal breaks.

METHODS

Retrospective, comparative, interventional, single-center study. Fifty-one eyes of fifty-one patients with primary RRD associated with inferior breaks and PVR grade C1 or more were reviewed over 3 years. Twenty-one eyes underwent PPV with encircling band 360° and thirty eyes underwent PPV with primary inferior retinectomy. The primary outcome was final anatomic success. Secondary outcomes included change in visual acuity, primary anatomical success, the mean number of operations, and incidence of postoperative complications.

RESULTS

Primary anatomical success of 85.7% was achieved in buckle group compared to 83.3% in retinectomy group (p = 0.82). Mean duration of follow-up and mean number of operations was 9.8 ± 2.26 and 9.97 ± 2.44 months; 1.24 ± 0.62 and 1.3 ± 0.75 in buckle group and retinectomy group, respectively, achieving final anatomical success of 95.2% for the buckle group and 90% for the retinectomy group with no statistical significant difference (p = 0.49). Although visual acuity (logMAR) was better in the buckle group in the 1st month, it became nearly equal thereafter during the follow-up period (p = 0.5).

CONCLUSION

Similar anatomical and functional outcomes were achieved by combining PPV with scleral buckle or inferior retinectomy for treatment of primary RRD with PVR and inferior breaks.

Postoperative Complications of Scleral Buckling

Scleral buckling has an important role in the repair of certain categories of rhegmatogenous retinal detachments. These include detachments in young phakic patients, detachments associated with dialysis, and also in conjuction with vitrectomy in patients who have sustained trauma or have developed proliferative vitreoretinopathy. However, it can be associated with significant postoperative complications. The most important ones are refractive change, intrusion or extrusion, infection, globe ischemia, and choroidal detachments, amongst others. Careful planning, appropriate patient selection, and good intraoperative technique can reduce the rate of these complications.

SCLERAL BUCKLE SURGERY FOR PRIMARY RETINAL DETACHMENT WITHOUT POSTERIOR VITREOUS DETACHMENT

PURPOSE

To present and analyze the anatomical and functional outcomes for scleral buckling (SB) in a group of patients with rhegmatogenous retinal detachment without posterior vitreous detachment.

METHODS

A total of 244 patients underwent SB from 2005 through 2014 by a single surgeon (A.W.E.). Forty patients (45 eyes) were identified as fulfilling the criteria of presenting with a rhegmatogenous retinal detachment without posterior vitreous detachment. Visual outcomes, preoperative retinal findings, and the SB technique were analyzed. The main outcome measure was the primary reattachment rate at 6 months after single surgery.

RESULTS

The mean age was 29 years (range 11-51 years). The mean follow-up period was 20 months. The mean refractive error was -5.16 diopters. Subretinal fluid drainage was performed in 17 eyes (37.8%). The anatomical success rate after single SB surgery at 6 months was 91.1%. The only factor that had statistically significant correlation with primary anatomical failure was development of subretinal hemorrhage during the drainage procedure (P = 0.03).

CONCLUSION

Despite an increasing trend toward primary vitrectomy for rhegmatogenous retinal detachment, an indication for SB is in younger patients without a preexisting posterior vitreous detachment. We showed a 91.1% success rate with a primary SB and 100% with a second surgery.

Long-term follow-up of vitrectomy, with or without 360° encircling buckle, for rhegmatogenous retinal detachment due to inferior retinal breaks

Objective

The aim of this study was to report and compare the anatomic and functional results of primary vitrectomy with and without 360° encircling scleral buckle (SB) for the treatment of rhegmatogenous retinal detachment (RRD) due to inferior retinal break(s).

Background

A variety of options, including SB, pars plana vitrectomy (PPV) with or without SB, and pneumatic retinopexy have been described as methods to repair RRDs. The use of additional SB with vitrectomy for RRD associated with inferior breaks has been a recent controversy after the introduction of transconjunctival cannula systems.

Patients and methods

A retrospective, interventional, comparative case study was performed. In this study, we reviewed 105 consecutive patients who underwent vitrectomy for primary RRD with inferior retinal break(s) at the vitreoretinal center, performed by a single surgeon. Ninety four patients (94 eyes) were followed up for at least 4 months after silicon oil removal (SOR), and were analyzed. They were divided into two groups: group I included 50 patients who underwent PPV alone + silicon oil (SO); and group II included 44 patients who underwent PPV with 360° SB + SO. The essential parameters were single-operation success rate (SOSR) before SOR, incidence of retinal redetachment after SOR, and final visual acuity.

Results

SOSR was obtained in 89 eyes (47 [94%] in group I and 42 [95.5%] in group II). From overall 59 phakic retinal detachments (RDs), SOSR was obtained in 56 eyes (30 in group I [93.8%] and 26 in group II [96.3%]) while from overall 35 aphakic or pseudophakic RDs, SOSR was obtained in 33 eyes (17 in group I [94.4%] and 16 in group II [94.1%]). Retinal redetachments after SOR occurred in three patients in group I and two patients in group II. Visual acuity improvement was greater in group I than in group II before SOR.

Conclusion

Both surgical procedures had similar reattachment rates. The addition of 360° SB to PPV + SO might not have additional benefits in patients with RD due to inferior retinal break.

A comparison of the anatomic successes of primary vitrectomy for rhegmatogenous retinal detachment with superior and inferior breaks

PURPOSE

To compare the anatomic success between repair of rhegmatogenous retinal detachment (RRD) with superior breaks and repair of RRD with inferior breaks, by performing primary vitrectomy and using similar techniques and the same gas.

METHODS

Eighty-two consecutive eyes of 80 patients with RRD were included in this retrospective comparative study. The eyes were divided into two groups according to the location of the breaks: superior (n = 62) and inferior (n = 20). All the patients underwent a standard, 3-port, 20-gauge pars plana vitrectomy with 20% sulphur hexafluoride gas tamponade performed by the same surgeon. The main outcome measured was the primary anatomic reattachment at 3 months after surgery.

RESULTS

The primary anatomic success rate in the inferior group was significantly lower than that in the superior group (80% versus 98%, p = 0.012). In the inferior group, the primary anatomic success rate in patients whose symptoms lasted for more than 2 weeks was significantly lower than that in others (5/9 versus 11/11, p = 0.026). Multivariate logistic regression analysis identified inferior break as the only independent risk factor for redetachment (odds ratio, 11.88; p = 0.034).

CONCLUSION

The anatomic success of primary vitrectomy for RRD with inferior breaks is lower than that for RRD with superior breaks. In particular, the duration of symptoms longer than 2 weeks is associated with a worse outcome in patients who had RRD with inferior breaks.

Visual changes after encircling band removal

AIMS

Visual changes over 1 year in 40 eyes were studied in 40 patients after removing scleral encircling bands.

METHODS

Encircling bands in 20 eyes were cut and removed. The fellow eyes of the above patients and the eyes of another 20 patients with encircling bands that were not removed over the same period served as controls. Intraocular pressure, best-corrected visual acuity, axial length, microperimetry and corneal topography were evaluated preoperatively and at 1 week and 1, 3 and 6 months postoperatively.

RESULTS

Both best-corrected visual acuity and astigmatism were significantly improved at 6 months postoperatively (p < 0.05 for each). Microperimetry examination showed that 2° fixation stability increased by 52.6% (p < 0.01), 4° fixation stability increased by 17.65% (p < 0.01) and 10° mean sensitivity increased by 30% (p < 0.05). However, the pre- and postoperative axial length showed no significant difference.

CONCLUSION

These results suggest that removing scleral encircling bands within the desired time postoperatively may give better visual outcomes due to decreased corneal astigmatism and improved average macular retinal light sensitivity. Removal of the encircling band is a safe, simple and feasible operation.

Ocular surface influences on corneal topography

The shape of a cornea, as measured by corneal topography, can be influenced by a variety of factors. Direct and obvious influences on corneal shape include corneal pathology, corneal surgery, and contact lenses. With the modern and widespread use of computerized videokeratoscopy, subtle topographic changes from other external and systemic influences can now be detailed. The purpose of this review is to examine ocular surface influences and indirect surgical, pathological, and pharmacological factors that affect the corneal shape and acquired topographic maps. The clinical consequences of altered corneal topography will be highlighted throughout.

Corneal topographic changes after scleral buckling

PURPOSE

To evaluate corneal topographic changes and induced corneal astigmatism after scleral buckling (SB).

METHODS

This interventional case series includes all patients who had undergone scleral buckling for rhegmatogenous retinal detachment (RRD) during a 1-year period. Patients were divided into four groups according to type and extent of scleral buckling which depended on the discretion of a retina specialist. Videokeratography was performed for all patients preoperatively and repeated 1 and 3 months after SB.

RESULTS

Thirty-nine eyes of 39 patients (29 male, 74.7%) with mean age of 50.35+/-20 years (range 13-80) were finally analyzed. There was no statistically significant difference among the groups in terms of preoperative corneal astigmatism, surface regularity index (SRI), surface asymmetry index (SAI), mean keratometry (mean K), and potential visual acuity (PVA ). Overall, preoperative mean K was 43.97+/-1.78 D, which reached 44.2+/-2.02 D and 43.92+/-2.16 D 1 and 3 months after the operation. Mean preoperative SRI was 0.58+/-0.4, which increased to 1.24+/-1.18 and 1.29+/-1.13 1 and 3 months after the operation respectively. Mean preoperative SAI was 0.39+/-0.21, which increased to 0.73+/-0.37 and 0.75+/-0.66 1 and 3 months after the procedure. Changes in SAI at 1 and 3 months following SB were significant (p values <0.001); however, these postoperative values were not significantly different. Mean preoperative PVA was 0.07+/-0.75 logMAR (equivalent to 20/20) but decreased to 0.24+/-0.25 (equivalent to 20/30) and 0.27+/-0.29 (equivalent to 20/40) 1 and 3 months after SB, respectively.

CONCLUSIONS

Significant changes in corneal topographic indices including increases in SRI and SAI and a concomitant decrease in PVA may occur after SB procedures. These induced changes must be considered and appropriately addressed postoperatively to provide the best possible corrected vision.

Scleral buckling combined with vitrectomy for the management of rhegmatogenous retinal detachment associated with inferior retinal breaks

AIM

The use of adjunctive scleral buckling during vitrectomy for retinal detachment associated with inferior breaks has been the recent focus of some debate. It has been suggested that any benefit might be outweighed by potential complications associated with buckling surgery. The purpose of this study was to compare the success rate of vitrectomy, gas, and supplementary scleral buckling with the results of two recently published case series suggesting that acceptable results in inferior break detachments can be achieved with vitrectomy and gas alone.

METHODS

A retrospective analysis of 60 consecutive patients with inferior break retinal detachments was conducted. All patients underwent vitrectomy, gas, and scleral buckling. In all cases, fellow eyes were examined under anaesthesia for retinal breaks if posterior vitreous detachment (PVD) had occurred at the time of presentation. Demographics, preoperative, and postoperative complications and outcome were recorded.

RESULTS

Primary retinal attachment at 3 months was achieved in 95% of patients. This exceeds success rates of published data of patients who underwent vitrectomy and gas without buckling (81-89%). In patients with PVD in the fellow eye, 53% had horseshoe tears and all were treated with cryopexy. No sight-threatening complications occurred, but five patients developed minor buckle-related complications postoperatively.

CONCLUSION

Supplementary scleral buckling is a safe procedure that improves and enhances primary success rates in inferior break detachments over vitrectomy and gas without buckling. There is a high rate of PVD-related breaks requiring treatment in the fellow eyes.

The Effect of Scleral Buckling Surgery on Corneal Astigmatism, Corneal Thickness, and Anterior Chamber Depth

PURPOSE

To evaluate the effect of scleral buckling surgery on corneal topography, corneal thickness, and anterior chamber depth.

METHODS

Thirty-two eyes of 32 patients who underwent encircling buckling surgery for rhegmatogenous retinal detachment were included in the study. Fellow eyes comprised the control group. Orbscan II topography system was used to determine the changes in corneal topography, corneal thickness, and anterior chamber depth before surgery and 1 week, 1 month, and 3 months after surgery. Statistical analyses used in the study were independent t test, paired t test, one way analysis of variance, and correlation analyses.

RESULTS

Postoperatively, mean central corneal astigmatism at 1 week, 1 month, and 3 months was 4.3 +/- 2.0 diopters (D), 3.3 +/- 1.6 D, and 3.1 +/- 1.0 D, respectively. The change between 1 week and 3 months was statistically significant. Central cornea was thickened at the first postoperative week. The thickness gradually decreased to the preoperative levels at 3 months. Anterior chamber depth decreased, and the anterior chamber remained shallow after the surgery. The comparison between preoperative (2.94 +/- 0.6 mm) and postoperative anterior chamber depth was statistically significant at 1 week (2.57 +/- 0.7 mm), 1 month (2.83 +/- 0.7 mm), and 3 months (2.73 +/- 0.6 mm).

CONCLUSIONS

Corneal changes after scleral buckling surgery were mild to moderate and the cornea almost resumed its preoperative parameters in 3 months' time. However, the anterior chamber remained shallow during 3 months of follow-up.

Laser in situ Keratomileusis for Correction of Myopia in Eyes After Retinal Detachment Surgery

PURPOSE

To evaluate the safety and efficacy of laser in situ keratomileusis (LASIK) for correction of myopia in eyes with previous retinal detachment surgery.

METHODS

A retrospective review was conducted of all consecutive eyes that underwent LASIK after retinal detachment surgery. Data was collected regarding previous ocular surgery and its time prior to LASIK, intra- and postoperative complications, and visual outcome measures pre- and postoperatively.

RESULTS

Ten eyes with previous retinal detachment surgery were scheduled for LASIK. One eye was excluded from data analysis as LASIK was aborted due to inadequate microkeratome suction because of conjunctival scarring. Nine eyes underwent an uneventful LASIK procedure. On average, LASIK was performed 130+/-123 months following retinal detachment surgery. Postoperative LASIK follow-up was 14.8+/-12.5 months. No significant intraoperative, postoperative, or retinal complications were observed. The mean preoperative spherical equivalent refraction was -9.00+/-3.00 diopters (D), uncorrected visual acuity (UCVA) was 0.06+/-0.02, and best spectacle-corrected visual acuity (BSCVA) was 0.64+/-0.16. At the end of follow-up, the mean spherical equivalent refraction was 0.65+/-0.88 D, mean UCVA was 0.57+/-0.14, and mean BSCVA was 0.72+/-0.19. Differences between BSCVA before and after LASIK were statistically significant (P=.038). At final follow-up, the safety index was 1.22 and efficacy index was 1.01.

CONCLUSIONS

Laser in situ keratomileusis was found to be a safe and efficient option for treating refractive errors in eyes with previous retinal detachment surgery.

Management of primary rhegmatogenous retinal detachment with inferior breaks

BACKGROUND

Rhegmatogenous retinal detachments (RRD) with inferior breaks are usually treated by scleral buckling (SB) or pars plana vitrectomy (PPV) or a combination of both methods. However, applying a SB during PPV may produce a risk of choroidal haemorrhage. Following a recent pilot study showing that such cases can be safely treated by PPV without SB the authors re-examined their management of RRD in which inferior breaks were present.

METHODS

All patients had a detached vitreous and a complex configuration of retinal breaks. A case-control study was performed to analyse the surgical methods and results of PPV on 48 consecutive patients with RRD associated with inferior breaks and 48 age/sex matched controls who underwent PPV for RRD without inferior breaks. Exclusion criteria were giant retinal tears, retinal dialysis, trauma, proliferative vitreoretinopathy (PVR) grade B or higher, schisis detachments, and eyes that had been operated previously for RRD. A simple algorithm was followed to manage patients with inferior breaks. All patients underwent a standard three port PPV with intraocular gas tamponade without supplementary SB. Patients were asked to posture face up or right or left side down for 1 week.

RESULTS

39 of the 48 patients (81.3%) with inferior breaks were treated successfully with one operation. 41 of 48 patients (85.4%) control patients achieved primary success. The final success rate was 95.8% in both groups. There was no statistical difference between the two groups. When all the cases of RRD were analysed (including external plomb/non-drain procedures) the primary success rate was 89% and final success rate 97.5%.

CONCLUSIONS

This study has shown that acceptable success rates can be achieved using PPV alone to treat RRD with inferior breaks. Complications are minimised and patients in this high risk group have an 81% chance of primary success. Pars plana vitrectomy and gas will successfully reattach the retina and a supplementary SB, to support the inferior retina, is unnecessary as the intraocular gas, and face up or, right or left side down positioning will tamponade breaks satisfactorily.

Corneal topographic changes following retinal surgery

Background

To study the effect of retinal/ vitreoretinal surgeries on corneal elevations.

Methods

Patients who underwent retinal/ vitreoretinal surgeries were divided into 3 groups. Scleral buckling was performed in 11 eyes (Group 1). In 8 (25%) eyes, vitreoretinal surgery was performed along with scleral buckling (Group 2). In 12 eyes, pars plana vitrectomy was performed for vitreous hemorrhage (Group 3). An encircling element was used in all the eyes. The parameters evaluated were best-corrected visual acuity (BCVA), change in axial length, and corneal topographic changes on Orbscan topography system II, preoperative and at 12 weeks following surgery.

Results

There was a statistically significant increase in anterior corneal elevation in all the three groups after surgery (p = 0.003, p = 0.008 & p = 0.003 respectively). The increase in posterior corneal elevation was highly significant in all the three groups after surgery (p = 0.0000, p = 0.0001 & p = 0.0001 respectively). The increase in the posterior corneal elevation was more than the increase in the anterior elevation and was significant statistically in all the three groups (group I: p = 0.02; group II: p = 0.01; group III: p = 0.008).

Conclusions

Retinal/ vitreoretinal surgeries cause a significant increase in the corneal elevations and have a greater effect on the posterior corneal surface.

Laser in situ keratomileusis as treatment for anisometropia after scleral buckling surgery

Scleral buckling is an excellent procedure for retinal reattachment but can induce disabling refractive errors. Laser in situ keratomileusis (LASIK) has been proven effective for the reduction of refractive errors induced by ophthalmic surgery. We describe the case of a 53-year-old man who developed symptomatic anisometropia after placement of a scleral buckle for repair of a rhegmatogenous retinal detachment (RD). After the scleral buckling procedure, he retained excellent best corrected visual acuity but could not tolerate spectacle or contact lens correction. Thirty-four months after the scleral buckling procedure, LASIK was performed to correct myopic astigmatism with excellent refractive and functional results. This case demonstrates that LASIK may be safe and effective for the correction of refractive errors induced by RD repair.

Corneal surface changes after pars plana vitrectomy and scleral buckling surgery

PURPOSE

To evaluate the changes in corneal shape after pars plana vitrectomy, encircling buckling surgery, and a combination of the 2 procedures.

SETTING

Assaf Harofeh Medical Center, Zrifin, and Goldshlager Eye Institute, Tel Hashomer, Israel.

METHODS

In a prospective clinical study, 61 eyes of 61 patients were assigned to 1 of 3 groups based on the type of procedure: pars plana vitrectomy, encircling buckle and pars plana vitrectomy, or encircling buckle. The eyes had corneal keratometry (TMS-1), visual acuity measurement, and videokeratography (TMS-1) preoperatively and 2 days, 1 week, and 1 and 3 months postoperatively. The topographic parameters statistically analyzed were the corneal surface cylinder, simulated keratometry, surface regularity index, surface asymmetry index, standard deviation of corneal power, average corneal power, and irregular astigmatism index.

RESULTS

The measurements of all topographic indices were statistically significantly different from baseline measures 2 and 7 days postoperatively in all 3 groups. However, at 1 and 3 months, there was no significant difference from preoperatively in any index. Postoperative best corrected visual acuity was statistically significantly different from preoperatively.

CONCLUSIONS

All corneal surface indices were significantly altered after all 3 types of surgery. Corneal surface measurements returned to preoperative values by 1 month postoperatively and remained stable until the final follow-up at 3 months.

Management of inferior retinal breaks during pars plana vitrectomy for retinal detachment

AIMS

To determine whether it is necessary to support inferior retinal breaks with a scleral explant during pars plana vitrectomy (PPV) for rhegmatogenous retinal detachment (RD).

METHODS

A prospective study was carried out on nine eyes of nine consecutive patients undergoing PPV for primary RD with associated inferior retinal breaks and no significant proliferative vitreoretinopathy.

RESULTS

Eight eyes were successfully reattached with a single operation. No cases presented with redetachment because of failed closure of the original inferior breaks.

CONCLUSIONS

It is not necessary to support inferior retinal breaks with a scleral explant during PPV for primary RD repair in selected cases.

Photorefractive Keratectomy for Visual Rehabilitation of Anisometropia Induced by Retinal Detachment Surgery

PURPOSE

To evaluate the efficacy of unilateral photorefractive keratectomy to correct anisometropia induced by retinal detachment surgery.

METHODS

Photorefractive keratectomy was performed in 10 eyes of 10 patients with anisometropia induced by previous retinal detachment surgery. The Aesculap Meditec MEL 60 excimer laser was used.

RESULTS

Preoperative mean spherical equivalent refraction was -5.20 D. Mean postoperative spherical equivalent refraction was -0.25 D after a mean follow-up of 12.9 months. Mean preoperative spherical equivalent refraction difference between two eyes of 4.87 D was decreased to a mean 0.60 D postoperatively (t-test, P < .0001). All patients were free of anisometropic symptoms after laser surgery.

CONCLUSION

Unilateral photorefractive keratectomy seems to be an effective method to correct anisometropia induced by conventional retinal detachment surgery, especially for patients with spectacle and contact lens intolerance.

Influence of amount and changes in axis of astigmatism on retinal image quality

We measured retinal image quality in astigmatic eyes, using the double-pass technique. We analyzed the influence of the amount of astigmatism and changes in axis of astigmatism on the eye's optical performance. Different amounts of astigmatism were obtained by variation of the cylindrical power of a lens situated in front of the eye, between 0.25-diopter (D) overcorrection and 1-D undercorrection at intervals of 0.25 D. Changes in the axis of astigmatism were obtained by rotation of the lens, which neutralizes the astigmatism in an angle of +/- 10 degrees at 5 degrees intervals. The results show the decrease in retinal image quality and the increase in the degree of image astigmatism obtained when the amount of astigmatism increases or the angle between the lens and the eye axis is other than zero. In general, the largest variations correspond to when the astigmatism changes from 0 to 0.25 D or when the axis changes from 0 degree to +/- 5 degrees. The reduction in optical performance is smaller in living eyes than in an eye model or in an artificial eye. The aberrations present in the living eye reduce the relative loss of retinal image quality introduced by astigmatism.

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.

The repair of rhegmatogenous retinal detachments. American Academy of Ophthalmology

The purpose of the Committee on Ophthalmic Procedure Assessments is to evaluate on a scientific basis new and existing ophthalmic tests, devices, and procedures for their safety, efficacy, clinical effectiveness, and appropriate uses. Evaluations include examination of available literature, epidemiological analyses when appropriate, and compilation of opinions from recognized experts and other interested parties. After appropriate review by all contributors, including legal counsel, assessments are submitted to the Academy's Board of Trustees for consideration as official Academy policy.

The role of vitrectomy in rhegmatogenous retinal detachment

Several conditions, such as detachment from posterior breaks or detachment with significant media opacities, may warrant vitrectomy as the primary procedure. In cases in which the preoperative retinal view is clear and a posterior break is definitively excluded, vitrectomy does not appear to offer significant advantage over scleral buckling other than a theoretically improved ability to examine the retina microscopically with scleral depression. Performing a vitrectomy for an uncomplicated retinal detachment from a small peripheral break in which scleral buckling would be the usual procedure of choice remains controversial. Although it may avoid the complications of scleral buckling, vitrectomy does have its own potential complications. The status of the lens, cornea, and configuration of the retinal tears and detachment should carefully be considered before vitrectomy. Proper patient selection and appropriate education are important factors in a successful outcome. Finally, from an economic viewpoint, the likelihood of success with vitrectomy in one procedure compared with other less expensive procedures should be considered.

Pars plana vitrectomy for the treatment of rhegmatogenous retinal detachment uncomplicated by advanced proliferative vitreoretinopathy

A consecutive series of 114 eyes (112 patients) undergoing pars plana vitrectomy for rhegmatogenous retinal detachment not complicated by severe proliferative vitreoretinopathy is presented (follow up 1 to 4 years; mean 19 months). The indications for vitrectomy fell into two main groups: (1) where the retinal view was poor and vitrectomy was required to clear media opacities to allow identification of retinal breaks (n = 62); and (2) where technically difficult breaks existed and vitrectomy with internal tamponade was used to relieve vitreoretinal traction and facilitate retinal break closure (n = 44). In some of these cases the need for scleral buckling was eliminated. A smaller third group (n = 8) existed where the position of the break(s) was uncertain in the presence of an adequate view. The success rate with one procedure was 74% and with further surgery retinal reattachment was achieved in 92%. At 6 months after further surgery, beyond which interval no new failures were encountered, best corrected visual acuity was improved in 92 eyes (81%), unchanged in 14(12%), and worse in eight (7%). We conclude that pars plana vitrectomy is an effective method for treatment of selected cases of rhegmatogenous retinal detachment not complicated by proliferative vitreoretinopathy.

The repair of rhegmatogenous retinal detachments. American Academy of Ophthalmology

Current techniques of rhegmatogenous retinal detachment repair allow most retinal detachments to be repaired successfully. The success of repair depends on a careful preoperative examination and choice of an appropriate surgical procedure. The surgical procedure must be tailored to the individual eye based on a detailed preoperative examination of the retina and vitreous. Postoperative complications are not infrequent compared to many other ophthalmic surgical procedures such as cataract extraction and strabismus repair. The surgeon must observe the eye carefully in the postoperative period to monitor and treat any complications as they arise. Improvements in surgical techniques coupled with a better understanding of the pathophysiology of rhegmatogenous retinal detachment continue to improve the anatomic and functional success of retinal detachment repair.

Postoperative astigmatism

With the numerous significant advances in surgical methodology--e.g., microinstrumentation, the operating microscope, the surgical keratometer, and intraocular lenses--that have been developed over the past two decades, both surgeons and patients have become increasingly aware of the final optic result of any surgical intervention. This is especially so since the development of refractive surgery, where good uncorrected vision is frequently the final arbiter of success. We have progressed to the stage where the optic manipulation of the cornea, whether intentional or otherwise, can be understood in terms of a number of variables. These include the preparation and closure of the surgical wound, the choice of suture material, and both intraoperative and postoperative manipulations. Where these have failed and postoperative astigmatism still occurs, a number of surgical procedures are available to reduce the astigmatic error to an acceptable level.

D-ACE surgical sequence for selected bullous retinal detachments

Forty-five out of 50 selected retinal detachments were successfully reattached by the D-ACE surgical sequence, that is, initial drainage of subretinal fluid followed by air injection into the vitreous, transcleral cryopexy, and definitive scleral buckling. The D-ACE sequence is recommended for difficult bullous detachments as a simple, safe, and effective alternative to non-drainage techniques.