Characteristics and surgical outcomes of rhegmatogenous retinal detachment following myopic LASIK.

PURPOSE: To describe the clinical features and surgical outcomes of rhegmatogenous retinal detachment (RRD) following myopic laser in situ keratomileusis (LASIK).
METHODS: In a retrospective, non-comparative case series, 46 eyes that had undergone vitreoretinal surgery for management of RRD following myopic LASIK were identified. Data was reviewed with emphasis on characteristics of the RRD, employed surgical techniques, and anatomic and visual outcomes.
RESULTS: Mean pre-LASIK myopia was -9.7±3.9 (range -4.00 to -18.00) diopters (D). Mean interval between LASIK and development of RRD was 11.6±11.2 months. Posterior vitreous detachment was present in 44 eyes (95.6%). The retinal breaks included flap tears in 36 (78.3%) eyes, giant tears in 8 (17.4%) eyes and atrophic holes in 2 (4.3%) eyes. In eyes with flap tears, the breaks were multiple, large or posterior to the equator in 24(66.7%) eyes. Retinal breaks were related to lattice degeneration in 20 (43.5%) eyes of which, three had history of prophylactic barrier laser photocoagulation. Scleral buckling was performed as the initial procedure in 32 (69.6%) eyes and primary vitrectomy was undertaken in 14 (30.4%) eyes. The initial surgical procedure failed in 14 (30.4%) eyes due to proliferative vitreoretinopathy (PVR). Retinal reattachment was finally achieved in 43 (93.4%) eyes. Postoperative visual acuity ≥20/40 and ≥20/200 was achieved in 16 (34.8%) and 25 (54.3%) eyes, respectively.
CONCLUSION: Post-LASIK retinal detachment has a complex nature in eyes with moderate to high myopia. The retinal detachment is complex in terms of size, number and location of retinal breaks, is associated with a high rate of PVR and entails unfavorable visual outcomes.

INTRODUCTION

The number of patients undergoing laser in situ keratomileusis (LASIK) has been rapidly growing worldwide over the past decade.1 Anterior segment complications of LASIK have been well documented in the literature.1,2 There have been growing reports of posterior segment complications after LASIK,3–14 which have inspired investigations in this regard.15 Retinal tears and detachments are the most important types of posterior segment complications; however, the cause and effect relationship remains controversial.The present study was planned to determine the clinical features and surgical outcomes of rhegmatogenous retinal detachment (RRD) following myopic LASIK. To the best of our knowledge, this is one of the largest case series of post-LASIK RRD in the literature.

METHODS

All vitreoretinal surgeons practicing in university affiliated and private referral centers were asked to fill an information sheet for cases of post-LASIK RRD which had been managed during the past 3 years with at least 6 months’ follow-up. LASIK procedures had been performed in a routine manner. The most common types of microkeratomes were the Chiron Automated Corneal Shaper (Chiron Vision, Irvine, USA) with a superior or inferior hinge or the Hansatome microkeratome (Chiron Vision, Irvine, USA) with a nasal hinge. Laser ablation was performed using the Summit (OmniMed Technology, Waltham, USA), Nidek EC-5000 (Nidek Co. Ltd, Gamagori, Japan), and Chiron Technolas Keracor 217C (Bausch & Lomb Surgical, Claremont, USA) excimer machines.

Characteristics of retinal breaks and grade of PVR were recorded. Retinal flap tears were considered "large" if greater than one clock hour, "posterior" when completely or partially located posterior to the equator, and giant when extending >90 degrees. The updated PVR classification was used.16 Surgical procedures included scleral buckling or pars plana vitrectomy (with or without lensectomy) with endolaser and internal tamponade or a combination of both techniques. The scleral buckling procedure consisted of placement of a segmental sponge (meridional or circumferential) without drainage of subretinal fluid, or an encircling buckle with drainage of subretinal fluid.

RESULTS

Forty-six eyes of 43 patients including 28(65.1%) male subjects with mean age of 32.8± 10.2 (range 19-62) years underwent vitreoretinal surgery for post-LASIK RRD from January 1999 to June 2002. Minimum follow-up period after retinal detachment surgery was 6 months. Operated eyes included the right eye in 20 patients, the left eye in 20 patients and both eyes in 3 patients. Mean pre-LASIK spherical equivalent refractive error was −9.7±3.9 (range −4.00 to −18.00) diopters (D). Interval between LASIK and RRD was 11.6±11.2 months on average, less than 6 months in 22 (47.8%) eyes and less than one year in 33 (71.7%) eyes.

Symptoms or signs of acute posterior vitreous detachment (PVD) were present in 44 (95.6%) eyes at the time of the diagnosis of RRD which was associated with fresh vitreous hemorrhage in 11 (23.9%) eyes. The RRD was macula-on in 6 (13.0%) eyes, involved 2 or 3 quadrants and the macula in 20 (43.5%) eyes, and was total in the other 20 (43.5%) eyes. Retinal breaks were located in the temporal quadrants in 84.8%; there were only 7 eyes with retinal breaks in the nasal quadrants. Retinal breaks included flap tears in 36 (78.3%) eyes, giant tears in 8 (17.4%) eyes and atrophic holes associated with lattice degeneration in 2 (4.3%) eyes of one patient. The latter patient developed a giant retinal tear in the left eye following scleral buckling surgery (Table 1, case #30). Of 8 eyes with giant retinal tears, the breaks were associated with lattice degeneration in 3 cases. All eyes with giant retinal tears were highly myopic with refractive errors exceeding −8.00 D. The interval between LASIK and diagnosis of RRD in eyes with giant retinal tears was 12 months or less in all 8 eyes and less than 6 months in 6 eyes. Of 36 eyes with flap retinal tears, the breaks were multiple, large or posterior in 24 (66.6%) eyes. Pre-LASIK myopia in eyes with flap retinal tears ranged from −4.00 D to −18.00 D with mean and mode of −9.00 D.

Table 1

patient characteristics

No.	Sex/Age(years)	Eye	Myopia(Diopter)	BCVA beforeLASIK	Lattice	Prophylacticbarrier laser	Relation of breaks with lattice	Interval between LASIK and RD(months)	Acute PVD	Vitreoushemorrhage	Type of retinal breaks	Status of macula	PVR	Primary treatment	Result of primarytreatment	Second treatment	Third treatment	Forthtreatment	FinalVA	Final anatomic result
1	M/31	OD	−10.00	20/25	+	+	+/−	4	+	+	Multiple, large flap tears	off	B	SB & Laser	Successful	New SB (localized RD)	–	–	20/25	Reattached
		OS	−10.00	20/25	+	−	+/−	10	+	+	Multiple, large flap tears	off	B	SB & Gas	Successful	Barrier Laser (New break)	–	–	20/30	Reattached
2	F/27	OD	−9.00	20/30	−	−	−	15	+	−	Large flap tears	On	A	SB, Sponge 507	Unsuccessful(PVR)	Intraocular gas	Lensx, Vitx, ELP, SO, band	SO removal	20/200	Reattached
3	M/37	OD	−9.00	20/25	−	−	−	36	+	+	Multiple, Large posterior flap tears	Off	B	Successful	–	–	–	20/200	Reattached
4	M/48	OS	−9.00	20/50	−	−	−	22	+	−	Large, posterior flap tear	Off	B	SB	Unsuccessful (posterior break)	Vitx, FGX	–	–	20/50	Reattached
5	M/42	OS	−10.00	20/50	+	−	+	9	+	−	Multiple flap tears	Off	B	SB	Unsuccessful(PVR)	PE, Vitx, ELP, SO	Repeat Vitx, relaxing retinotomy	Repeat Vitx, Repeat retinotomy, SO	5/200	Reattached
6	M/43	OD	−6.00	20/25	+	−	+	2	+	−	Multiple flap tears	Off	C	Lensx, Vitx ELP, SO, band	successful	SO removal	–	–	10/200	Reattached
7	M/22	OD	−11.50	20/25	+	−	+	2	+	+	GRT, Multiple flap tears	Off	C	Lensx, Vitx ELP, SO, band	Unsuccessful(PVR)	Reoperation: repeat vitx & SO(failed)	Patient refusal	–	5/200	Partially reattached
8	M/19	OD	−14.00	20/120	+	+	+	1.5	+	−	Multiple flap tears	Off	B	SB	Unsuccessful(PVR)	Lensx, vitx, ELP, SO	SO removal(leading to redetachment)	repeat vitx, SO	10/200	reattached
9	M/35	OD	−10.00	20/30	+	+	−	36	+	−	flap tear	On	A	SB(Meridional sponge 507)	Successful	–	–	–	20/30	Reattached
10	M/38	OD	−10.50	20/30	−	−	−	5.5	+	+	Large, posterior flap tear	Off	A	SB(Meridional sponge 507)	Unsuccessful(open break)	Intraocular gas(leading to new inferior break)	inferior buckle: sponge 505	–	20/40	Reattached
11	M/20	OS	−4.00	20/15	−	−	−	12	+	−	Multiple flap tears	On	B	SB	Successful	Barrier laser	–	–	20/20	Reattached
12	M/39	OS	−11.00	20/60	+	−	−	2	+	+	GRT	Off	C	Vitx, ELP, SO, band	Successful	SO removal	–	–	20/200	Reattached
13	F/21	OD	−11.00	20/50	+	−	+	24	+	−	flap tears	Off	B	SB	Successful	–	–	–	20/100	Reattached
14	F/38	OS	−12.00	20/40	−	−	−	9	+	−	flap tears	Off	B	SB	Successful	–	–	–	20/100	Reattached
15	F/30	OS	−14.00	20/50	+	−	+	2	+	−	Multiple flap tears	Off	C	SB	Unsuccessful(PVR)	Vitx, FGX	Patient refusal	–	LP	Prephtisis bulbi
16	F/36	OS	−10.00	20/20	−	−	−	2	+	−	flap tears	Off	B	SB	Unsuccessful(PVR)	Vitx, SO	–	–	10/200	Inf. redetachment
17	M/26	OD	−6.00	20/20	+	−	+	4	+	+	Multiple flap tears	Off	A	SB&Gas	Successful	–	–	–	20/30	Reattached
18	M/18	OD	−9.00	20/25	−	−	−	1	+	−	flap tears	Off	A	SB	Successful	–	–	–	20/40	Reattached
19	M/23	OS	−18.00	20/40	−	−	−	2.5	+	+	GRT	Off	B	Lensx, Vitx, ELP, SO	Unsuccessful(New break)	Segmental sponge(inferior)	SO removal	–	5/200	Reattached
20	F/40	OD	−11.00	20/30	−	−	−	12	+	+	Large, posterior flap tears	Off	B	SB(Meridional sponge 507)	Unsuccessful(PVR)	Repeat Vitx, FGX	Patient refusal	–	HM	Total redetachment
21	M/62	OD	−12.00	20/30	−	−	−	1.5	+	−	Multiple flap tears	Off	B	SB	Successful	–	–	–	20/40	Reattached
22	M/21	OS	−12.00	20/30	−	−	−	12	+	−	GRT	Off	B	Lensx, vitx ELP, SO, band	Successful	SO removal	–	–	20/100	Reattached
23	F/31	OD	−7.00	20/30	+	−	+	4	+	−	Multiple Flap tears	Off	A	SB	Successful	–	–	–	20/50	Reattached
24	F/25	OS	−8.00	20/25	−	−	−	3	+	−	Flap tears	Off	B	SB	Successful	–	–	–	20/40	Reattached
25	F/54	OS	−6.00	20/25	−	−	−	8	+	−	Large, posterior Flap tears	Off	B	SB&Gas	Successful	–	–	–	20/100	Reattached
		OD	−4.00	20/20	+	−	+	24	+	−	Flap tears	Off	B	SB	Unsuccessful(PVR)	Intraocular gas	Vitx, OS	SO removal	10/200	Reattached
26	M/56	OS	−6.00	20/20	+	−	+	20	+	−	Flap tears	Off	B	SB	Successful	–	–	–	2040	Reattached
27	M/45	OS	−5.00	20/20	−	−	−	36	+	+	Multiple, posterior Flap tears	Off	A	Vitx, ELP, FGX, band	Unsuccessful(PVR)	Repeat intraocular gas	Repeat Vitx, SO	SO removal	16/200	Reattached
28	F/35	OS	−8.00	20/160	−	−	−	36	+	−	Multiple Flap tears	Off	A	SB	Successful	–	–	–	20/160	Reattached
29	M/35	OS	−9.00	20/160	−	−	−	4.5	+	+	Multiple Flap tears	Off	–	Primary vitx	Unsuccessful(PVR)	Repeat vitx	Repeat vitx	–	LP	Reattached(OA)
30	M/30	OD	−9.00	20/20	+	−	+	24	−	−	Atrophic holes	On	–	SB	Successful	Vitx for pucker	–	–	20/30	Reattached
		OS	−9.00	20/20	+	−	+	24	−	−	Atrophic holes	On	–	SB	Successful	Vitx due to GRT & Vit. Hem.	PE & PCIOL	–	20/50	Reattached
31	M/38	OS	−10.00	20/40	+	−	+	1.5	+	−	Flap tear	Off	B	SB	Unsuccessful(PVR)	Vitx, MPC, ELP, SO	ECCE, PCIOL, SO removal	Repeat vitx, SO	20/200	Reattached
32	F/26	OD	−18.00	20/40	−	−	−	36	+	−	Multiple Flap tear	Off	A	SB	Successful	–	–	–	20/120	Reattached
33	M/20	OD	−15.00	20/30	−	−	−	12	+	−	Flap tear	Off	A	SB	Unsuccessful(PVR)	Vitx, FGX	Lensx, Vitx, MPC, SO	SO removal	5/200	Reattached
34	M/42	OD	−8.00	20/20	+	−	+	5	+	−	Multiple Flap tear	Off	A	SB	Successful	–	–	–	20/30	Reattached
35	F/31	OS	−11.00	20/25	−	−	−	9	+	−	Large Flap tear	Off	B	Primary Vitx & band	Successful	–	–	–	20/200	Reattached
36	M/25	OD	−8.00	20/25	+	−	+	3	+	−	Flap tear	Off	B	SB	Successful	–	–	–	20/40	Reattached
37	M/30	OS	−9.00	20/25	+	−	+	8	+	−	Flap tear	Off	B	SB	Successful	–	–	–	20/40	Reattached
38	F/28	OS	−11.00	10/10	+	−	+	2	+	−	Flap tear	Off	A	SB	Successful	–	–	–	20/20	Reattached
39	M/25	OD	−8.00	20/25	−	−	−	3	+	−	GRT	Off	C	Vitx, ELP, SO, band	Unsuccessful(PVR)	Reoperation	SO removal	–	20/200	Reattached
40	M/30	OS	−9.00	20/25	−	−	−	24	+	−	Large flap tear	Off	C	Vitx, ELP, SO, band	Unsuccessful(PVR)	Reoperation	SO removal	–	20/200	Reattached
41	M/35	OD	−13.00	20/30	−	−	−	4.5	+	−	GRT	Off	C	Vitx, ELP, SO, band	Successful	SO removal	–	–	5/200	Reattached
42	F/25	OD	−8.00	20/25	−	−	−	12	+	−	GRT	Off	C	Vitx, ELP, SO, band	Successful	SO removal	–	–	HM	Reattached(OA)
43	F/30	OS	−9.00	20/25	+	−	+	5	+	−	GRT	Off	C	Vitx, ELP, SO, band	Successful	–	–	–	20/50	Reattached

BCVA, best-corrected visual acuity; LASIK, Laser in situ keratomileusis; RD, retinal detachment; PVD, posterior vitreous detachment; M, male; F, female; OD, right eye; OS, left eye; GRT, giant retinal tear; PVR, proliferative vitreoretinopathy; SB, clear buckling; RD, retinal detachment; Lensx, lensectomy; Vitx, vitrectomy; ELP, endolaser photocoagulation; SO, silicon oil; FGX, fluid/gas exchange; PE, phacoemulsification; PCIOL, posterior chamber intraocular lense; ECCE, extracapsular cataract extraction; MPC, membrane peeling cutting; HM, hand motions; LP, light perception; Vit, vitreous; Hem, hemorrhage; inf., inferior; OA, optc atrophy

Based on available data, lattice degeneration had been detected in 22 (47.8%) eyes prior to LASIK. Multiple areas of lattice degeneration were present circumferentially in multiple rows in most cases. Retinal breaks resulting in RRD were related to lattice degeneration in 20 (43.5%) eyes. Only 3 (13.6%) eyes had undergone prophylactic barrier laser photocoagulation before LASIK. In these eyes, new retinal breaks resulting in RRD were located at the margin of the treated lattice degeneration in 2 eyes (Table 1, right eyes of cases #1 and #5). In the remaining case, the flap tear was unrelated to the previously treated lattice degeneration (Table 1, case #9). An asymptomatic retinal tear was seen at the posterior margin of an area of lattice degeneration in one eye, (Table 1, case #9). Both eyes in another patient showed retinal breaks unrelated to lattice degeneration (Table 1, case #1).

Thirty-two eyes (69.6%) underwent scleral buckling as the initial procedure. A meridional sponge was placed in four eyes without drainage of subretinal fluid. Segmental circumferential solid silicone tire with an encircling band together with drainage of subretinal fluid was performed in the remaining cases. Retinopexy was induced either by intraoperative cryopexy or postoperative laser photocoagulation around the retinal breaks. Intravitreal gas injection was performed in 6 eyes as a supplemental procedure in the same session or in a second session because the retinal breaks remained open after scleral buckling. New retinal breaks and subsequent RDs were managed by additional scleral buckling and/or barrier laser photocoagulation in 3 eyes. New retinal break formation was a complication of intravitreal gas injection in one of these eyes (Table 1, case #10).

Of 32 eyes undergoing scleral buckling as primary treatment, 12 (37.5%) required reoperations including pars plana vitrectomy with endolaser photocoagulation and internal tamponade. Retinal reattachment could not be achieved despite placement of a buckle in one eye due to the presence of a large, posterior retinal break. Vitrectomy was indicated in one patient due to macular pucker in one eye and for management of a late-onset giant retinal tear in the fellow eye (Table 1, case #30). PVR was the cause of failure in 9 other eyes after scleral buckling. Removal of the lens (lensectomy or phacoemulsification) was combined with vitrectomy for management of anterior PVR in most such cases (Table 1).

Fourteen eyes (30.4%) underwent primary vitrectomy, endolaser photocoagulation and internal tamponade combined with an encircling band. Six of these eyes had multiple, large or posterior retinal breaks, with or without vitreous hemorrhage, including 3 eyes with PVR C; the remaining 8 eyes had giant retinal tears, 5 of which showed signs of PVR grade C before surgery. Of the 14 eyes undergoing pars plana vitrectomy as primary treatment, retinal reattachment was achieved in 8 cases but reoperations were required in the remaining 6 eyes which was due to PVR in five eyes.

Overall, PVR grade C was present in 8 of 46 (17.3%) eyes before surgery. Of these, only one eye with PVR grade CP1 underwent scleral buckling as the initial procedure while pars plana vitrectomy was performed in the remaining seven eyes. Multiple vitreoretinal procedures were necessary in these eyes.

Silicone oil (1000 cs or 5000 cs viscosity) was used for internal tamponade in 18 eyes during initial surgery or reoperations. Silicone oil was removed 3 to 6 months later in cases which the retina was reattached posterior to the buckle. Retinal redetachment, however, occurred in 2 eyes necessitating reoperations (Table 1).

Corneal flap dislocation occurred in 3 eyes; in two eyes (Table 1, right eye of case #1 and #27) this happened when the surgeon removed the corneal epithelium. The interval between LASIK and retinal detachment surgery was 36 and 4 months in these cases respectively. In one eye (Table 1, case #6), flap dislocation occurred despite no manipulation. This eye had undergone vitreoretinal surgery two months after LASIK. Flap dehiscence was managed at the end of surgery by irrigating the stromal bed and repositioning the flap followed by application of a light pressure patch. One day after the operation, the LASIK flap remained in position in the first two cases. Nevertheless in the third case, it seemed to be slightly displaced with some wrinkling requiring flap fixation with three separate 10/0 nylon sutures which were removed two weeks later; the flap remained stable and the cornea was clear thereafter.

Overall, 27 (58.7%) eyes required additional procedures. Complete retinal reattachment was finally achieved in 43 (93.4%) eyes. Three patients with retinal detachments complicated by PVR refused further operations. Before LASIK, all eyes had best-corrected visual acuity (BCVA) of 20/40 or better. Postoperative visual acuity of 20/40 or better and 20/200 or better was achieved in 16 (34.8%) and 25 (54.3%) eyes, respectively. Four eyes had final visual acuity of light perception (LP) to hand motions due to total retinal redetachment in 2 eyes (Table 1, cases #15 and #20) and optic atrophy in 2 other eyes (Table 1, cases #29 and #42). Optic atrophy was presumed to be due to perioperative intraocular pressure (IOP) elevation.

DISCUSSION

Axial myopia is one of the most important risk factors for RRD. Moderate and high myopia predispose the eye to retinal detachment because of an increased rate and severity of vitreous liquefaction and subsequent PVD which occur at a significantly younger age in myopic eyes. Moreover, myopic eyes are more likely to develop retinal tears following PVD. Lattice degeneration is also more common in myopic eyes which further increases the risk of retinal tears when PVD occurs.17

In a study performed to identify risk factors for idiopathic RRD, myopia emerged as the strongest one. Eyes with refractive error of −1.00 to −3.00 D had a four-fold risk as compared to emmetropic eyes; with refractive errors exceeding −3.00 D, the risk was nearly 10 times. The incidence of retinal detachment is about 30 per 100,000 per year in the general population vs 0.7% to 6% per year in myopic patients.17 The authors concluded that RD is primarily dependent on the architecture of the eye.

The role of LASIK as a potential additive risk factor for RRD in myopic eyes has been an issue of debate.5–14,18 It has been suggested that LASIK is a "closed eye injury" and can be considered as an additional precipitating factor.18 Theoretically, shock waves generated by the excimer laser may increase the risk of PVD.5 Arevalo et al8,10–12 hypothesized that IOP rise to levels greater than 60 mmHg induced by the pneumatic suction ring may exert traction on the vitreous base by anteroposterior compression and equatorial expansion leading to retinal breaks. Flaxel et al15 observed an actual increase in axial length after placement of the suction ring without any change in anterior chamber depth and concluded that changes in ocular dimensions may induce posterior vitreous detachment. This may also lead to anterior movement of the vitreous base resulting in traction on areas of lattice degeneration. In their clinical and experimental studies, Luna et al3 reported the occurrence of PVD following LASIK. Qin et al19 found PVD in 5 of 6 eyes with RRD among 18,342 post-LASIK eyes. In our study, PVD was observed in 44 of 46 eyes with post-LASIK RRD. Delayed retinal break formation following PVD has already been described20 which may explain the long interval between LASIK and RRD in some cases.

Several forms of retinal detachment have been considered as "complex"; these include cases with large and/or multiple retinal tears, retinal detachments due to posterior or giant retinal tears, and those with PVR.16 Giant retinal tears occur most frequently in association with myopia and ocular trauma. When both factors coexist, the risk of giant retinal tear is further increased. Farah and co-authors9 reported two cases of giant retinal tears following LASIK for high myopia; the retinal detachments developed less than 3 months after surgery and final visual acuity was 20/400 and LP. Ozdamar et al5 reported a case of simultaneous bilateral retinal detachment associated with giant retinal tears after LASIK in a highly myopic patient. Another case of bilateral retinal detachment associated with giant retinal tears has been reported in a highly myopic patient two months after LASIK.14 A significant percentage of our cases (17.3%) had giant retinal tears; all eyes were highly myopic and the time interval between LASIK and RRD was short in most cases. In addition to giant retinal tears, more than half of our patients had multiple, large posterior retinal flap tears. Overall, 70% of our cases (8 with GRT and 22 with multiple, large and posterior retinal flap tears) had complexities related to the type and size of retinal breaks. This is a higher rate in comparison with previous reports in the literature.6–14 Chan et al21 also reported complexity in their post-LASIK RRD cases including two or more breaks in 53%, 3 or more breaks in 26.7%, bilateral involvement in 30%, PVR in 8.3%, GRT in 6.7%, and extensive retinal dialysis in 5.0%. The high incidence of PVR in our series may be due to presence of large and multiple retinal breaks22–24 and the greater extent of RRD.23,25–27 Moreover, many cases were referred by anterior segment surgeons, possibly prolonging the interval between onset of RRD to diagnosis.

LASIK procedures using commercially available excimer laser machines have been approved in the United States for up to 14 D of myopia.28 In other countries higher degrees of myopia have been corrected using this technique. Nevertheless, the results have generally been worse in cases with more than 7D of myopia.28,29 In addition to structural tissue alterations, highly myopic eyes may be prone to an increased risk of retinal detachment following LASIK because of greater total laser energy and longer duration of shock waves.3 Luna et al3 noticed that PVD was more prevalent in high as compared to low myopia. Diminished hyaluronic acid and loss of compartmentalization predispose highly myopic eyes to acute PVD and development of retinal tears including GRT.

In a study by Chan et al,21 characteristics of post-LASIK retinal breaks and detachments were evaluated in 60 eyes with documented pre-LASIK retinal examinations. A large percentage of eyes had substantial myopia and complex vitreoretinal complications. Of the 60 eyes, 15% and 40% developed retinal lesions within 1 and 6 months after LASIK, respectively. Eyes that developed more extensive RD had significantly higher myopia than eyes with limited RD within 12 months after LASIK.

Our study was not designed to identify the incidence of RRD after LASIK; we were also unable to investigate the cause and effect relationship between LASIK and RRD. A large percentage of our patients were highly myopic and the occurrence of complicated RRD in such eyes is not unexpected. One may only hypothesize that LASIK might be a precipitating factor in such predisposed eyes. To prove such a relationship between LASIK and RRD, a prospective study needs to be conducted.

In our series, 43.5% of eyes with RD had one or multiple retinal breaks associated with lattice degeneration. Arevalo et al8 and Aras et al7 reported such an association in 22.5% and 40% of their patients respectively. Lattice degeneration is a significant risk factor for RRD and frequently observed on fundus examination of myopic eyes.30 Lattice degeneration is usually extensive and may be present in multiple rows in these eyes. The efficacy of prophylactic treatment of lattice degeneration in reducing the risk of RRD remains unclear.31 In a study by Folk et al32 prophylactic laser treatment of lattice degenerations was ineffective in eyes with more than 6 diopters of myopia or with more than 6 clock hours of lattice. Three patients in our series and some cases in other series developed RD following LASIK despite prophylactic barrier laser treatment of lattice degeneration. Moreover, in the series reported by Farah et al9 and also in our series, some retinal breaks were located in apparently normal areas. LASIK may aggravate pre-existing retinal pathologies including invisible vitreoretinal adhesions which may result in retinal tear formation in locations with no prior visible changes.16 In a retrospective study investigating the correlation between pre- and post-LASIK retinal lesions; the authors noticed that prophylactic treatment of lattice degeneration and retinal breaks prior to LASIK did not guarantee the prevention of vitreoretinal complications in highly myopic eyes.33

Multiple vitreoretinal procedures were performed in most of our patients and final retinal reattachment was achieved in 93.4 % of eyes which favorably compares to figures reported by Arevalo et al8,10–12 and Aras et al.7 Most patients in our series showed a dramatic decrease in visual acuity after multiple vitreoretinal operations despite retinal reattachment. Aras et al7 presented 10 cases of RD following LASIK, final BCVA was less than 20/40 in all cases and 20/200 or worse in 7 eyes. These observations show that functional results may not be as satisfactory as anatomic results in eyes with post-LASIK RRD.

Surgery in these eyes may be associated with intraoperative complications of rapid corneal haziness and LASIK flap dehiscence. A case of corneal flap dehiscence 7 months after LASIK has been reported during RD surgery.34 A similar complication occurred in 3 eyes in our series. The interval between LASIK and RD surgery was less than 6 months in two eyes and 36 months in the other eye. These observations are in accordance with a study which showed absence of bridging collagen fibers and cells between the flap and the stromal bed, indicating lack of wound repair at the LASIK interface.35

In conclusion, post-LASIK RRD usually occurs in eyes with moderate to high myopia and may have a complex nature in terms of size, number, location and type of retinal breaks, as well as a high rate of PVR. Surgeons may face corneal flap complications in these eyes. Multiple procedures may be needed and final visual results are usually not favorable. Although the retrospective nature of our study precludes determining a cause and effect relationship between LASIK and vitreoretinal complications, our findings suggest that every LASIK candidate should undergo a meticulous vitreoretinal examination. High myopia and/or presence of extensive circumferential lattice degeneration may be a warning sign. The patient should be informed that prophylactic treatment of peripheral retinal lesions does not have a proven efficacy in preventing RD following LASIK.