- Email: [email protected]
The Correlation between Height of Macular Detachment and Visual Outcome in Macula-Off Retinal Detachments of ≤7 Days’ Duration
The Correlation between Height of Macular Detachment and Visual Outcome in MaculaOff Retinal Detachments of <7 Days’ Duration William Ross, MD, FRCSC, Adrian Lavina, MD, Matthew Russell, MBChB, FRANZCO, David Maberley, MD, FRCSC Objective: To determine the relationship between the height of macular detachment and visual recovery after treatment of macula-off retinal detachments (RDs) of ⱕ7 days’ duration. Design: Prospective comparative case series. Participants: Fifty-two eyes of 52 consecutive patients who presented to one institution with macula-off RDs of ⱕ7 days’ duration were prospectively enrolled in the study. Methods: Gender, age, lens status, duration of macular detachment, and presenting visual acuity (VA) were recorded for all patients. Each patient underwent a 3-dimensional B-scan ultrasound examination at the time of presentation. The height of macular detachment was calculated using the mean measured distance between the retinal pigment epithelium and the outer neurosensory retina 3, 4, and 5 mm temporal to the center of the optic nerve head. All patients underwent primarily successful reattachment surgery within 7 days of macular detachment. Final vision was recorded with a minimum of 6 months’ follow-up. Main Outcome Measure: Postoperative VA evaluated as a continuous variable. Results: For the 52 subjects, a direct correlation between lower height of macular detachment and better final postoperative vision (dependent variable) was observed with linear regression (slope, 0.114; 95% confidence interval, 0.022– 0.206; P ⫽ 0.016). Multivariate linear regression analysis with a backward stepwise approach did not demonstrate any significant association between postoperative vision and predictor variables (gender, age, lens status, duration of macular detachment, macular height, and preoperative vision), except for macular height. Conclusion: Lower height of macular detachment correlates with better visual recovery after treatment of macula-off RDs of ⱕ7 days’ duration. Ophthalmology 2005;112:1213–1217 © 2005 by the American Academy of Ophthalmology.
With modern surgical techniques to repair retinal detachments (RDs), a primary anatomic success rate of ⬎90% can be expected.1–5 Despite this high level of anatomic success, improvement of central vision remains compromised because of permanent functional damage to the macula after detachment.6 –9 Although many factors have been found to influence visual recovery, the most important predictor for visual recovery after Originally received: July 12, 2004. Accepted: January 7, 2005. Manuscript no. 240552. From the Department of Ophthalmology, University of British Columbia, Vancouver, Canada. Presented at: Society of American Retinal Specialists Annual Meeting, August, 2004; San Diego, California, and Retina Society meeting, October, 2004; Baltimore, Maryland. The authors have no financial interest in any device or technology used in the study. Correspondence and reprint requests to William H. Ross, MD, FRCSC, University of British Columbia, 400 – 805 West Broadway, Vancouver, BC, V5Z 1K1, Canada. E-mail: [email protected]. © 2005 by the American Academy of Ophthalmology Published by Elsevier Inc.
RD surgery is preoperative visual acuity (VA).4,5,10 –12 Patients with macula-on detachments have a high likelihood of retaining their preoperative vision. In macula-off detachments, visual recovery is often compromised. Patient age, duration of detachment, and height of macular involvement have been reported to be the most important preoperative factors affecting visual recovery.10,13–16 Until recently, technology has not been available to measure the height of macular involvement to determine reliably its effect on final visual recovery in macula-off detachments. Using 3-dimensional B-scan ultrasonography, this study demonstrates that the most crucial factor in recovery of central vision after repair of macula-off detachments of ⱕ7 days’ duration is the height of macular involvement before surgery.
Patients and Methods This prospective study reviewed 52 patients with macula-off RDs who underwent successful reattachment surgery within 1 week of ISSN 0161-6420/05/$–see front matter doi:10.1016/j.ophtha.2005.01.040
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Ophthalmology Volume 112, Number 7, July 2005
Figure 1. Patient 9, with a macular height of 0.8 mm. Preoperative vision, 20/200; postoperative vision, 20/30.
macular involvement. The study was conducted over an 18-month period (May 1, 2002–November 1, 2003). Internal review board ethics approval was obtained for the study. All patients were interviewed and underwent a full ocular evaluation. The following data were collected for each patient: age, gender, preoperative Snellen and logarithm of the minimum angle of resolution (logMAR) VAs, and lens status. All patients were interviewed to assign accurately the onset of macular detachment to a specific 24-hour period within the first week. Duration of macular detachment was defined as the interval between the onset of symptoms of macular detachment and macular reattachment with surgery. Primary surgical failures were excluded. Also, patients who underwent initial successful retinal reattachment but subsequently had redetachment within 6 months of primary repair were excluded from the study. Other patients excluded were those who had previous retinal surgery or prior ocular disease affecting central vision, such as macular degeneration, macular holes, degenerative myopia, and amblyopia. After a complete retinal examination, all patients underwent 3-dimensional B-scan ultrasonography to define the full extent of the detachment and to locate the center of the optic nerve and macular region accurately.17 Patients were in a seated position for 5 minutes before measurements were taken. All measurements were performed within 24 hours before surgical repair. The 3dimensional ultrasound machine used in this study consisted of a conventional B-mode ultrasound probe and receiver unit (i-Scan, Ophthalmic Technologies Inc., Ontario, Canada) coupled to a PowerMac G3 (Apple Computer Inc., Cupertino, CA) for the
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generation of digital 3-dimensional images. The B-scan probe was inserted into a rotating servomotor sleeve that rotates the probe through 180° for image acquisition. After digitization of the ultrasound image, the computer microprocessor maps the individual 2-dimensional images into a 3-dimensional grid from which any 2-dimensional cut can be displayed on the video output. After image acquisition, measurements were taken from a transverse macular cut at the level of the center of the optic nerve. Three points on the RPE 3, 4, and 5 mm temporal to the center of the nerve were identified. Digital calipers were used at these points to measure and record the perpendicular distance between the retinal pigment epithelial surface and the outer neurosensory retina of the overlying detached retina (Figs 1, 2). The 3 measurements were averaged to determine the height of macular detachment. The method of repair included pneumatic retinopexy, scleral buckling, primary pars plana vitrectomy (PPV), and combined vitrectomy scleral buckling surgery. Best-corrected postoperative vision was documented by the referring ophthalmologist at 6 months after surgery or beyond. All Snellen acuities were transformed into their logMAR equivalent (negative log of the decimal Snellen acuity). For non-Snellen acuity, the following equivalents were used: counting fingers (CF), 1.6, and hand movements, 1.9. All patients were observed for a minimum of 6 months after retinal reattachment. A statistical analysis was conducted correlating final vision with preoperative factors that included gender, patient age, duration of macular detachment within the first week, height of macular detachment, preoperative vision, and duration of follow-up. For our primary outcome, postoperative VA (logMAR representation), all potential predictor variables were evaluated individually using simple linear regression. Continuous variables included age, preoperative logMAR vision, duration of macular detachment, and follow-up duration (months). Lens status was categorized dichotomously as either phakic or pseudophakic (there were no aphakic patients recruited). As well, multivariate linear regression was performed using a backwards stepwise approach with a liberal exclusion P value of 0.15. All variables were included in the initial model before the removal process. SPSS18 was used for all analyses.
Figure 2. Patient 40, with a macular height of 1.6 mm. Preoperative vision, 20/400; postoperative vision, 20/100.
Ross et al 䡠 Correlation between Height of Macular Detachment and Visual Outcome Table 1. Summary of Collected Data of 52 Patients Ranked by Best Final Visual Acuity
Patient
Gender
Age (yrs)
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52
Female Male Female Female Male Male Female Male Male Male Male Male Male Male Female Male Male Male Female Male Female Male Female Female Male Male Female Male Male Female Male Female Male Male Male Male Female Female Male Male Male Male Male Male Male Male Male Female Male Male Male Female
60.9 56.7 39.6 68.4 60.6 51.7 61.1 62.2 55.2 46.8 59.4 45.5 14.1 74.0 72.6 85.5 38.8 58.5 60.8 74.8 67.1 60.6 82.4 73.2 48.8 58.8 77.1 52.3 60.3 29.0 54.5 71.1 53.2 69.3 65.2 61.2 28.8 71.5 53.8 63.4 73.5 58.3 46.7 61.1 77.4 57.4 67.1 79.7 77.3 56.3 63.5 78.5
Eye
Lens Status
Duration of Macular Detachment (Days)
Left Right Right Right Right Right Right Right Right Right Left Right Left Right Left Left Right Left Left Left Left Left Right Left Right Right Left Right Left Left Right Right Right Right Right Right Left Left Left Right Right Left Right Right Left Right Left Left Right Right Right Left
Pseudophakic Phakic Phakic Phakic Pseudophakic Phakic Phakic Phakic Pseudophakic Phakic Phakic Pseudophakic Phakic Pseudophakic Pseudophakic Pseudophakic Phakic Phakic Pseudophakic Pseudophakic Pseudophakic Pseudophakic Pseudophakic Pseudophakic Pseudophakic Phakic Pseudophakic Phakic Phakic Pseudophakic Pseudophakic Phakic Phakic Pseudophakic Phakic Phakic Phakic Phakic Pseudophakic Phakic Phakic Pseudophakic Phakic Pseudophakic Pseudophakic Pseudophakic Pseudophakic Pseudophakic Phakic Phakic Phakic Pseudophakic
2 2 2 3 5 2 2 3 3 7 2 4 3 3 7 4 1 7 7 1 1 2 7 1 5 5 2 2 1 1 1 1 7 3 1 7 6 7 4 7 4 5 2 7 7 4 5 7 3 2 1 7
Macular Height (mm)
Preoperative Snellen Vision
Preoperative logMAR Vision
Final Snellen Vision
Final logMAR Vision
Follow-up (mos)
0.6 1.1 2 1 0.5 0.5 0.5 0.7 0.8 1 1.1 1.1 1.2 1.2 1.6 2 0.3 0.5 0.5 0.6 0.8 0.8 1.1 1.3 1.3 1.9 2.1 4.9 0.4 0.4 0.7 0.8 0.9 1 1.3 1.3 0.7 1.5 1.3 1.6 1.8 2.6 5 5.5 2.6 2.9 4.4 4.6 5.2 1.7 0.7 1.9
20/400 20/400 CF CF HM CF CF HM 20/200 20/200 20/400 HM 20/300 CF CF HM CF CF 20/200 20/400 20/400 HM CF 20/80 CF 20/200 CF CF HM 20/200 20/400 20/40 CF HM 20/60 HM 20/200 HM HM 20/400 HM HM 20/200 20/300 CF 20/200 HM HM CF CF CF CF
1.30 1.30 1.60 1.60 1.90 1.60 1.60 1.90 1.00 1.00 1.30 1.90 1.18 1.60 1.60 1.90 1.60 1.60 1.00 1.30 1.30 1.90 1.60 0.60 1.60 1.00 1.60 1.60 1.90 1.00 1.30 0.30 1.60 1.90 0.48 1.90 1.00 1.90 1.90 1.30 1.90 1.90 1.00 1.18 1.60 1.00 1.90 1.90 1.60 1.60 1.60 1.60
20/20 20/20 20/20 20/25 20/30 20/30 20/30 20/30 20/30 20/30 20/30 20/30 20/30 20/30 20/30 20/30 20/40 20/40 20/40 20/40 20/40 20/40 20/40 20/40 20/40 20/40 20/40 20/40 20/50 20/50 20/50 20/50 20/50 20/50 20/50 20/50 20/70 20/70 20/80 20/100 20/100 20/100 20/100 20/100 20/200 20/200 20/200 20/200 20/200 20/300 CF CF
0.00 0.00 0.00 0.10 0.18 0.18 0.18 0.18 0.18 0.18 0.18 0.18 0.18 0.18 0.18 0.18 0.30 0.30 0.30 0.30 0.30 0.30 0.30 0.30 0.30 0.30 0.30 0.30 0.40 0.40 0.40 0.40 0.40 0.40 0.40 0.40 0.54 0.54 0.60 0.70 0.70 0.70 0.70 0.70 1.00 1.00 1.00 1.00 1.00 1.18 1.60 1.60
7.3 7.4 7.6 6.9 12.6 7.5 6.7 13.3 8.3 11.5 7.3 9.3 17.5 8.8 9.7 6.4 6.5 6.8 8.0 10.8 18.4 6.0.0 6.7 13.3 6.1 8.1 8.7 10.4 6 6.2 9.0 6.3 7.0 10.2 11.9 8.5 14.1 18.6 8.2 7.0 6.7 9.7 18.7 7.2 7.6 9.9 10.5 10.6 11.3 11.3 6.7 7.6
CF ⫽ counting fingers; HM ⫽ hand movements; logMAR ⫽ logarithm of the minimum angle of resolution.
Results A total of 52 patients were found to have a primary rhegmatogenous detachment for which the patient could accurately determine the onset of macular detachment and the detachment fulfilled the inclusion criteria outlined above. The age of patients ranged from 14.1 to 85.5 years, with a mean age of 60.5 years. There were 36 (69.2%) male and 16 (30.8%) female patients. There were 30
(57.7%) right eyes and 22 (42.3%) left eyes. Twenty-six (50%) were phakic, and 26 (50%) were pseudophakic. The mean duration of macular detachment was 3.75 days (range, 1–7 days). The macular height measured 3 diopters. Ultrasonography ranged from 0.3 to 5.5 m. The method of repair included pneumatic retinopexy in 29 (55.8%) cases, scleral buckling in 10 (19.2%), and primary PPV in 9 (17.3%), and 4 (7.7%) patients underwent combined vitrectomy–scleral buckling. All patients included in the study had
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Ophthalmology Volume 112, Number 7, July 2005 Table 2. Univariate Regression Analysis with Postoperative Vision as Dependent Variable Variable
P Value
Macular height Gender Age Lens status Duration of detachment Preoperative vision Follow-up duration
0.0012* 0.505 0.083 0.727 0.134 0.437 0.797
*Significant variable.
successful reattachments with the primary procedure. The mean preoperative vision was 1.87 logMAR (20/1483 Snellen), and the mean postoperative vision was 0.47 logMAR (20/60 Snellen). Thirty-six patients (69%) regained 20/50 or better vision, 14 (27%) regained 20/60 to 20/300 vision, and 2 (4%) had a final vision of CF. The duration of follow-up ranged from 6 to 18.7 months, with a mean of 9.4 months. A summary of the collected data based on final VA is shown in Table 1. For our 52 participants, we attempted to predict postoperative VA from our series of 7 risk factors presented in Table 2. Each variable initially was evaluated individually against final vision using simple linear regression. The slope of the regression line was only significant (⬎0) for macular height, indicating that postoperative logMAR acuity tends to increase (worsen) as preoperative macular height rises (slope, 0.114; 95% confidence interval, 0.022– 0.206; P ⫽ 0.016); Multivariate analysis using a backward stepwise approach did not demonstrate any significant association between postoperative vision and predictor variables (gender, age, lens status, duration of macular detachment, macular height, and preoperative vision), except for macular height.
Discussion In 1998, Ross and Kozy reported a series of 104 patients with macula-off RD of ⱕ7 days duration.13 All patients underwent scleral buckling surgery within 24 hours of presentation. Fifty nine percent of patients regained 20/50 or better vision, 25% regained VA between 20/60 and 20/200, and 5% of patients were left with VA of less than 20/200. There was no statistical difference in visual recovery in patients operated within 1 to 2 days, 3 to 5 days, or 5 to 7 days after macular involvement (P ⫽ 0.533). The major conclusion of the study is that the length of macular involvement within the first week did not influence the postoperative VA, with approximately 59% of patients in the 3 groups regaining 20/50 or better vision. Some patients with macula-off detachments for 1 to 2 days did not regain VA of greater than 20/50, whereas other patients with macula-off for 5 to 7 days regained 20/20 vision. The difference in recovery of vision was felt to be due to the height of macular involvement. In this series, 38 of 52 patients (69%) regained 20/50 or better vision, 14 (27%) regained 20/60 to 20/300 vision, and 2 (4%) were left with CF vision. The visual recovery for the entire group of patients is similar to that of other series.14,16,19 –22
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Previous studies examining the effect of height of macular detachment on visual recovery after RD have relied on clinical examination to evaluate macular height.10,16 The height of macular detachment in both studies was graded as either high or low based on the ophthalmoscopic appearance of the macula. In an article by Tani et al, a study of specific morphologic changes in the macula was undertaken to learn whether they had any predictive value regarding final VA.10 The extent of retinal evaluation at the fovea, cystoid macular edema, and preretinal fibrosis was graded. These factors were studied by multivariate regression analysis. Only the extent of macular retinal elevation (P ⫽ 0.003) showed a positive relationship to final VA. Girard and Karpouzas, in a study of 542 macula off RDs, graded the height of macular detachment clinically as either high or low.16 Their results suggested a positive relationship between shallow macular detachment and achieving a vision of 20/40 or better. To the best of our knowledge, the current series is the first to use 3-dimensional B-scan ultrasonography to measure accurately the height of macular involvement before retinal reattachment surgery and to demonstrate that the height of macular detachment is the most important preoperative variable influencing recovery of good central vision in macula-off detachments of ⱕ7 days’ duration. A direct correlation between height of macular detachment and postoperative vision, measured as a continuous variable, was found (P ⫽ 0.016) Animal studies also support this concept that the height of macular detachment is a significant determinant of the extent of outer retinal damage. In experimental detachments in owl monkeys, Machemer found that photoreceptor cell degeneration increased as the distance between the pigment epithelial layer and the photoreceptors increased.7 A study by Mervin et al in a feline model for RD supports this earlier finding.8 In macula-off detachments, disruption and loss of photoreceptor outer segments, loss of outer nuclear layer neurons (nuclei of photoreceptors), and thinning of the outer nuclear layer by approximately 20% were evident within 72 hours. Synaptic disruption within the outer plexiform layer was also present. Recently, Lewis et al23,24 were able to show that these changes could be substantially mitigated by maintaining hyperoxic conditions during the period of detachment, leading to the conclusion that loss of oxygen supply from the choriocapillaris is an important factor resulting in outer retinal damage after RD. The diffusion of nutrients, especially oxygen, through the subretinal fluid to the neurosensory retina may be a key factor for visual recovery. The outer neurosensory retina may be damaged more extensively because of reduced diffusion of oxygen and essential nutrients with higher macula-off detachments than with shallow macula-off detachments. In summary, the height of macular detachment preoperatively has been shown to be the most important factor in final recovery in patients who presented with macula-off RDs of ⱕ1 week’s duration. Visual recovery is inversely correlated with the height of macular detachment before surgery.
Ross et al 䡠 Correlation between Height of Macular Detachment and Visual Outcome
References 1. Chignell AH, Fison LG, Davies EW, et al. Failure in retinal detachment surgery. Br J Ophthalmol 1973;57:525–30. 2. Rachal WF, Burton TC. Changing concepts of failure after retinal detachment surgery. Arch Ophthalmol 1979;97:480 –3. 3. Kreissig I. Prognosis of return of macular function after retinal reattachment. Mod Probl Ophthalmol 1977;18:415–29. 4. Sharma T, Challa JK, Ravishankar KV, Murugesan R. Scleral buckling for retinal detachment: predictors for anatomic failure. Retina 1994;14:338 – 43. 5. Grizzard WS, Hilton GF, Hammer ME, Taren D. A multivariate analysis of anatomic success of retinal detachments treated with scleral buckling. Graefes Arch Clin Exp Ophthalmol 1994;232:1–7. 6. Burton TC. Recovery of visual acuity after retinal detachment involving the macula. Trans Am Ophthalmol Soc 1982;80: 475–97. 7. Machemer R. Experimental retinal detachment in the owl monkey. II. Histology of the retina and pigment epithelium. Am J Ophthalmol 1968;66:396 – 410. 8. Mervin K, Valter K, Maslim J, et al. Limiting photoreceptor death and deconstruction during experimental retinal detachment: the value of oxygen supplementation. Am J Ophthalmol 1999; 128:155– 64. 9. Sabates NR, Sabates FN, Sabates R, et al. Macular changes after retinal detachment surgery. Am J Ophthalmol 1989;108: 22–9. 10. Tani P, Robertson DM, Langworthy A. Prognosis for central vision and anatomic reattachment in rhegmatogenous retinal detachment with macula detached. Am J Ophthalmol 1981; 92:611–20. 11. Burton TC. Preoperative factors influencing anatomic success rates following retinal detachment surgery. Trans Sect Ophthalmol Am Acad Ophthalmol Otolaryngol 1977;83: OP499 –505.
12. Kaufman PL. Prognosis of primary rhegmatogenous retinal detachments. 2. Accounting for and predicting final visual acuity in surgically reattached cases. Acta Ophthalmol (Copenh) 1976;54: 61–74. 13. Ross WH, Kozy DW. Visual recovery in macula-off rhegmatogenous retinal detachments. Ophthalmology 1998;105:2149–53. 14. Burton TC, Lambert RW Jr. A predictive model for visual recovery following retinal detachment surgery. Ophthalmology 1978;85:619 –25. 15. Hassan T, Sarrafizadeh R, Ruby A, et al. The effect of duration of macular detachment on results after the scleral buckle repair of primary, macula-off retinal detachments. Ophthalmology 2002;109:146 –52. 16. Girard P, Karpouzas I. Visual acuity after buckling surgery. Ophthalmologica 1995;209:323– 8. 17. Maberley D, Fisher Y, Carvahlo C, et al. Variability of threedimensional ultrasonography for assessment of intraocular tumors. Can J Ophthalmol 2002;37:283–9. 18. SPSS [computer program]. Version 11.5. Chicago: SPSS Inc. 19. Hilton GF, Norton EW, Curtin VT, Gass JDM. Retinal detachment surgery: a comparison of diathermy and cryosurgery. Bibl Ophthalmol 1969;79:440 – 8. 20. Gundry MF, Davies EW. Recovery of visual acuity after retinal detachment surgery. Am J Ophthalmol 1974;77:310 – 4. 21. Kusaka S, Toshino A, Ohashi Y, Sakaue E. Long-term visual recovery after scleral buckling for macula-off retinal detachments. Jpn J Ophthalmol 1998;42:218 –22. 22. McPherson AR, O’Malley RE, Butler RW, Beltangady SS. Visual acuity after surgery for retinal detachment with macular involvement. Ann Ophthalmol 1982;14:639 – 45. 23. Grupposo SS. Visual acuity following surgery for retinal detachment. Arch Ophthalmol 1975;93:327–30. 24. Lewis GP, Talaga KC, Linberg KA, et al. The efficacy of delayed oxygen therapy in the treatment of experimental retinal detachment. Am J Ophthalmol 2004;137:1085–95.
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With modern surgical techniques to repair retinal detachments (RDs), a primary anatomic success rate of ⬎90% can be expected.1–5 Despite this high level of anatomic success, improvement of central vision remains compromised because of permanent functional damage to the macula after detachment.6 –9 Although many factors have been found to influence visual recovery, the most important predictor for visual recovery after Originally received: July 12, 2004. Accepted: January 7, 2005. Manuscript no. 240552. From the Department of Ophthalmology, University of British Columbia, Vancouver, Canada. Presented at: Society of American Retinal Specialists Annual Meeting, August, 2004; San Diego, California, and Retina Society meeting, October, 2004; Baltimore, Maryland. The authors have no financial interest in any device or technology used in the study. Correspondence and reprint requests to William H. Ross, MD, FRCSC, University of British Columbia, 400 – 805 West Broadway, Vancouver, BC, V5Z 1K1, Canada. E-mail: [email protected]. © 2005 by the American Academy of Ophthalmology Published by Elsevier Inc.
RD surgery is preoperative visual acuity (VA).4,5,10 –12 Patients with macula-on detachments have a high likelihood of retaining their preoperative vision. In macula-off detachments, visual recovery is often compromised. Patient age, duration of detachment, and height of macular involvement have been reported to be the most important preoperative factors affecting visual recovery.10,13–16 Until recently, technology has not been available to measure the height of macular involvement to determine reliably its effect on final visual recovery in macula-off detachments. Using 3-dimensional B-scan ultrasonography, this study demonstrates that the most crucial factor in recovery of central vision after repair of macula-off detachments of ⱕ7 days’ duration is the height of macular involvement before surgery.
Patients and Methods This prospective study reviewed 52 patients with macula-off RDs who underwent successful reattachment surgery within 1 week of ISSN 0161-6420/05/$–see front matter doi:10.1016/j.ophtha.2005.01.040
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Ophthalmology Volume 112, Number 7, July 2005
Figure 1. Patient 9, with a macular height of 0.8 mm. Preoperative vision, 20/200; postoperative vision, 20/30.
macular involvement. The study was conducted over an 18-month period (May 1, 2002–November 1, 2003). Internal review board ethics approval was obtained for the study. All patients were interviewed and underwent a full ocular evaluation. The following data were collected for each patient: age, gender, preoperative Snellen and logarithm of the minimum angle of resolution (logMAR) VAs, and lens status. All patients were interviewed to assign accurately the onset of macular detachment to a specific 24-hour period within the first week. Duration of macular detachment was defined as the interval between the onset of symptoms of macular detachment and macular reattachment with surgery. Primary surgical failures were excluded. Also, patients who underwent initial successful retinal reattachment but subsequently had redetachment within 6 months of primary repair were excluded from the study. Other patients excluded were those who had previous retinal surgery or prior ocular disease affecting central vision, such as macular degeneration, macular holes, degenerative myopia, and amblyopia. After a complete retinal examination, all patients underwent 3-dimensional B-scan ultrasonography to define the full extent of the detachment and to locate the center of the optic nerve and macular region accurately.17 Patients were in a seated position for 5 minutes before measurements were taken. All measurements were performed within 24 hours before surgical repair. The 3dimensional ultrasound machine used in this study consisted of a conventional B-mode ultrasound probe and receiver unit (i-Scan, Ophthalmic Technologies Inc., Ontario, Canada) coupled to a PowerMac G3 (Apple Computer Inc., Cupertino, CA) for the
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generation of digital 3-dimensional images. The B-scan probe was inserted into a rotating servomotor sleeve that rotates the probe through 180° for image acquisition. After digitization of the ultrasound image, the computer microprocessor maps the individual 2-dimensional images into a 3-dimensional grid from which any 2-dimensional cut can be displayed on the video output. After image acquisition, measurements were taken from a transverse macular cut at the level of the center of the optic nerve. Three points on the RPE 3, 4, and 5 mm temporal to the center of the nerve were identified. Digital calipers were used at these points to measure and record the perpendicular distance between the retinal pigment epithelial surface and the outer neurosensory retina of the overlying detached retina (Figs 1, 2). The 3 measurements were averaged to determine the height of macular detachment. The method of repair included pneumatic retinopexy, scleral buckling, primary pars plana vitrectomy (PPV), and combined vitrectomy scleral buckling surgery. Best-corrected postoperative vision was documented by the referring ophthalmologist at 6 months after surgery or beyond. All Snellen acuities were transformed into their logMAR equivalent (negative log of the decimal Snellen acuity). For non-Snellen acuity, the following equivalents were used: counting fingers (CF), 1.6, and hand movements, 1.9. All patients were observed for a minimum of 6 months after retinal reattachment. A statistical analysis was conducted correlating final vision with preoperative factors that included gender, patient age, duration of macular detachment within the first week, height of macular detachment, preoperative vision, and duration of follow-up. For our primary outcome, postoperative VA (logMAR representation), all potential predictor variables were evaluated individually using simple linear regression. Continuous variables included age, preoperative logMAR vision, duration of macular detachment, and follow-up duration (months). Lens status was categorized dichotomously as either phakic or pseudophakic (there were no aphakic patients recruited). As well, multivariate linear regression was performed using a backwards stepwise approach with a liberal exclusion P value of 0.15. All variables were included in the initial model before the removal process. SPSS18 was used for all analyses.
Figure 2. Patient 40, with a macular height of 1.6 mm. Preoperative vision, 20/400; postoperative vision, 20/100.
Ross et al 䡠 Correlation between Height of Macular Detachment and Visual Outcome Table 1. Summary of Collected Data of 52 Patients Ranked by Best Final Visual Acuity
Patient
Gender
Age (yrs)
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52
Female Male Female Female Male Male Female Male Male Male Male Male Male Male Female Male Male Male Female Male Female Male Female Female Male Male Female Male Male Female Male Female Male Male Male Male Female Female Male Male Male Male Male Male Male Male Male Female Male Male Male Female
60.9 56.7 39.6 68.4 60.6 51.7 61.1 62.2 55.2 46.8 59.4 45.5 14.1 74.0 72.6 85.5 38.8 58.5 60.8 74.8 67.1 60.6 82.4 73.2 48.8 58.8 77.1 52.3 60.3 29.0 54.5 71.1 53.2 69.3 65.2 61.2 28.8 71.5 53.8 63.4 73.5 58.3 46.7 61.1 77.4 57.4 67.1 79.7 77.3 56.3 63.5 78.5
Eye
Lens Status
Duration of Macular Detachment (Days)
Left Right Right Right Right Right Right Right Right Right Left Right Left Right Left Left Right Left Left Left Left Left Right Left Right Right Left Right Left Left Right Right Right Right Right Right Left Left Left Right Right Left Right Right Left Right Left Left Right Right Right Left
Pseudophakic Phakic Phakic Phakic Pseudophakic Phakic Phakic Phakic Pseudophakic Phakic Phakic Pseudophakic Phakic Pseudophakic Pseudophakic Pseudophakic Phakic Phakic Pseudophakic Pseudophakic Pseudophakic Pseudophakic Pseudophakic Pseudophakic Pseudophakic Phakic Pseudophakic Phakic Phakic Pseudophakic Pseudophakic Phakic Phakic Pseudophakic Phakic Phakic Phakic Phakic Pseudophakic Phakic Phakic Pseudophakic Phakic Pseudophakic Pseudophakic Pseudophakic Pseudophakic Pseudophakic Phakic Phakic Phakic Pseudophakic
2 2 2 3 5 2 2 3 3 7 2 4 3 3 7 4 1 7 7 1 1 2 7 1 5 5 2 2 1 1 1 1 7 3 1 7 6 7 4 7 4 5 2 7 7 4 5 7 3 2 1 7
Macular Height (mm)
Preoperative Snellen Vision
Preoperative logMAR Vision
Final Snellen Vision
Final logMAR Vision
Follow-up (mos)
0.6 1.1 2 1 0.5 0.5 0.5 0.7 0.8 1 1.1 1.1 1.2 1.2 1.6 2 0.3 0.5 0.5 0.6 0.8 0.8 1.1 1.3 1.3 1.9 2.1 4.9 0.4 0.4 0.7 0.8 0.9 1 1.3 1.3 0.7 1.5 1.3 1.6 1.8 2.6 5 5.5 2.6 2.9 4.4 4.6 5.2 1.7 0.7 1.9
20/400 20/400 CF CF HM CF CF HM 20/200 20/200 20/400 HM 20/300 CF CF HM CF CF 20/200 20/400 20/400 HM CF 20/80 CF 20/200 CF CF HM 20/200 20/400 20/40 CF HM 20/60 HM 20/200 HM HM 20/400 HM HM 20/200 20/300 CF 20/200 HM HM CF CF CF CF
1.30 1.30 1.60 1.60 1.90 1.60 1.60 1.90 1.00 1.00 1.30 1.90 1.18 1.60 1.60 1.90 1.60 1.60 1.00 1.30 1.30 1.90 1.60 0.60 1.60 1.00 1.60 1.60 1.90 1.00 1.30 0.30 1.60 1.90 0.48 1.90 1.00 1.90 1.90 1.30 1.90 1.90 1.00 1.18 1.60 1.00 1.90 1.90 1.60 1.60 1.60 1.60
20/20 20/20 20/20 20/25 20/30 20/30 20/30 20/30 20/30 20/30 20/30 20/30 20/30 20/30 20/30 20/30 20/40 20/40 20/40 20/40 20/40 20/40 20/40 20/40 20/40 20/40 20/40 20/40 20/50 20/50 20/50 20/50 20/50 20/50 20/50 20/50 20/70 20/70 20/80 20/100 20/100 20/100 20/100 20/100 20/200 20/200 20/200 20/200 20/200 20/300 CF CF
0.00 0.00 0.00 0.10 0.18 0.18 0.18 0.18 0.18 0.18 0.18 0.18 0.18 0.18 0.18 0.18 0.30 0.30 0.30 0.30 0.30 0.30 0.30 0.30 0.30 0.30 0.30 0.30 0.40 0.40 0.40 0.40 0.40 0.40 0.40 0.40 0.54 0.54 0.60 0.70 0.70 0.70 0.70 0.70 1.00 1.00 1.00 1.00 1.00 1.18 1.60 1.60
7.3 7.4 7.6 6.9 12.6 7.5 6.7 13.3 8.3 11.5 7.3 9.3 17.5 8.8 9.7 6.4 6.5 6.8 8.0 10.8 18.4 6.0.0 6.7 13.3 6.1 8.1 8.7 10.4 6 6.2 9.0 6.3 7.0 10.2 11.9 8.5 14.1 18.6 8.2 7.0 6.7 9.7 18.7 7.2 7.6 9.9 10.5 10.6 11.3 11.3 6.7 7.6
CF ⫽ counting fingers; HM ⫽ hand movements; logMAR ⫽ logarithm of the minimum angle of resolution.
Results A total of 52 patients were found to have a primary rhegmatogenous detachment for which the patient could accurately determine the onset of macular detachment and the detachment fulfilled the inclusion criteria outlined above. The age of patients ranged from 14.1 to 85.5 years, with a mean age of 60.5 years. There were 36 (69.2%) male and 16 (30.8%) female patients. There were 30
(57.7%) right eyes and 22 (42.3%) left eyes. Twenty-six (50%) were phakic, and 26 (50%) were pseudophakic. The mean duration of macular detachment was 3.75 days (range, 1–7 days). The macular height measured 3 diopters. Ultrasonography ranged from 0.3 to 5.5 m. The method of repair included pneumatic retinopexy in 29 (55.8%) cases, scleral buckling in 10 (19.2%), and primary PPV in 9 (17.3%), and 4 (7.7%) patients underwent combined vitrectomy–scleral buckling. All patients included in the study had
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Ophthalmology Volume 112, Number 7, July 2005 Table 2. Univariate Regression Analysis with Postoperative Vision as Dependent Variable Variable
P Value
Macular height Gender Age Lens status Duration of detachment Preoperative vision Follow-up duration
0.0012* 0.505 0.083 0.727 0.134 0.437 0.797
*Significant variable.
successful reattachments with the primary procedure. The mean preoperative vision was 1.87 logMAR (20/1483 Snellen), and the mean postoperative vision was 0.47 logMAR (20/60 Snellen). Thirty-six patients (69%) regained 20/50 or better vision, 14 (27%) regained 20/60 to 20/300 vision, and 2 (4%) had a final vision of CF. The duration of follow-up ranged from 6 to 18.7 months, with a mean of 9.4 months. A summary of the collected data based on final VA is shown in Table 1. For our 52 participants, we attempted to predict postoperative VA from our series of 7 risk factors presented in Table 2. Each variable initially was evaluated individually against final vision using simple linear regression. The slope of the regression line was only significant (⬎0) for macular height, indicating that postoperative logMAR acuity tends to increase (worsen) as preoperative macular height rises (slope, 0.114; 95% confidence interval, 0.022– 0.206; P ⫽ 0.016); Multivariate analysis using a backward stepwise approach did not demonstrate any significant association between postoperative vision and predictor variables (gender, age, lens status, duration of macular detachment, macular height, and preoperative vision), except for macular height.
Discussion In 1998, Ross and Kozy reported a series of 104 patients with macula-off RD of ⱕ7 days duration.13 All patients underwent scleral buckling surgery within 24 hours of presentation. Fifty nine percent of patients regained 20/50 or better vision, 25% regained VA between 20/60 and 20/200, and 5% of patients were left with VA of less than 20/200. There was no statistical difference in visual recovery in patients operated within 1 to 2 days, 3 to 5 days, or 5 to 7 days after macular involvement (P ⫽ 0.533). The major conclusion of the study is that the length of macular involvement within the first week did not influence the postoperative VA, with approximately 59% of patients in the 3 groups regaining 20/50 or better vision. Some patients with macula-off detachments for 1 to 2 days did not regain VA of greater than 20/50, whereas other patients with macula-off for 5 to 7 days regained 20/20 vision. The difference in recovery of vision was felt to be due to the height of macular involvement. In this series, 38 of 52 patients (69%) regained 20/50 or better vision, 14 (27%) regained 20/60 to 20/300 vision, and 2 (4%) were left with CF vision. The visual recovery for the entire group of patients is similar to that of other series.14,16,19 –22
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Previous studies examining the effect of height of macular detachment on visual recovery after RD have relied on clinical examination to evaluate macular height.10,16 The height of macular detachment in both studies was graded as either high or low based on the ophthalmoscopic appearance of the macula. In an article by Tani et al, a study of specific morphologic changes in the macula was undertaken to learn whether they had any predictive value regarding final VA.10 The extent of retinal evaluation at the fovea, cystoid macular edema, and preretinal fibrosis was graded. These factors were studied by multivariate regression analysis. Only the extent of macular retinal elevation (P ⫽ 0.003) showed a positive relationship to final VA. Girard and Karpouzas, in a study of 542 macula off RDs, graded the height of macular detachment clinically as either high or low.16 Their results suggested a positive relationship between shallow macular detachment and achieving a vision of 20/40 or better. To the best of our knowledge, the current series is the first to use 3-dimensional B-scan ultrasonography to measure accurately the height of macular involvement before retinal reattachment surgery and to demonstrate that the height of macular detachment is the most important preoperative variable influencing recovery of good central vision in macula-off detachments of ⱕ7 days’ duration. A direct correlation between height of macular detachment and postoperative vision, measured as a continuous variable, was found (P ⫽ 0.016) Animal studies also support this concept that the height of macular detachment is a significant determinant of the extent of outer retinal damage. In experimental detachments in owl monkeys, Machemer found that photoreceptor cell degeneration increased as the distance between the pigment epithelial layer and the photoreceptors increased.7 A study by Mervin et al in a feline model for RD supports this earlier finding.8 In macula-off detachments, disruption and loss of photoreceptor outer segments, loss of outer nuclear layer neurons (nuclei of photoreceptors), and thinning of the outer nuclear layer by approximately 20% were evident within 72 hours. Synaptic disruption within the outer plexiform layer was also present. Recently, Lewis et al23,24 were able to show that these changes could be substantially mitigated by maintaining hyperoxic conditions during the period of detachment, leading to the conclusion that loss of oxygen supply from the choriocapillaris is an important factor resulting in outer retinal damage after RD. The diffusion of nutrients, especially oxygen, through the subretinal fluid to the neurosensory retina may be a key factor for visual recovery. The outer neurosensory retina may be damaged more extensively because of reduced diffusion of oxygen and essential nutrients with higher macula-off detachments than with shallow macula-off detachments. In summary, the height of macular detachment preoperatively has been shown to be the most important factor in final recovery in patients who presented with macula-off RDs of ⱕ1 week’s duration. Visual recovery is inversely correlated with the height of macular detachment before surgery.
Ross et al 䡠 Correlation between Height of Macular Detachment and Visual Outcome
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