rapid visual recovery after penetrating keratoplasty for keratoconus

Original Article

Rapid visual recovery after penetrating keratoplasty forkeratoconusGerard Sutton FRANZCO,1 Chris Hodge BAppSc(Orth)2 and Charles NJ McGhee PhD FRANZCO3

1Department of Ophthalmology, Sydney Eye Hospital, and 2The Eye Institute, Chatswood, Sydney, New South Wales, Australia; and3Department of Ophthalmology, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand

ABSTRACT

Purpose: To ascertain the level and speed of visual recoveryafter penetrating keratoplasty for keratoconus.

Method: A retrospective review was performed of 100 con-secutive cases of penetrating keratoplasty for keratoconus,performed between 1999 and 2005. Review assessed visualfunction and the speed at which patients achieved a func-tional best corrected visual acuity (BCVA) of �6/12 eitherwith glasses or phoropter. Analysis of visual, refractive andkeratometric results were made on 76 eyes that hadreached 6 months after suture removal. Intraoperative andpostoperative complications including graft rejections wererecorded.

Results: Post keratoplasty, 43.4%, 78.9% and 96.1% ofpatients achieved a BCVA of 6/12 or better by 1, 3 and6 months, respectively.The mean time to achieve a BCVA of6/12 was 9.6 weeks. Only 5.3% of patients required a rigidgas permeable contact lens. Overall 42.4% of patients hadunaided visual acuity of 6/12 or better at 12 months. Themean refractive cylinder and standard deviation was2.78 � 1.6 D, and the mean spherical equivalent was-1.12 � 2.9 D. There were no significant intraoperativecomplications, and although 3.9% of eyes had at least onegraft rejection episode there were no graft failures.

Conclusion: Penetrating keratoplasty is an effective methodfor treating advanced keratoconus. By 3 months almost allpatients are able to achieve a BCVA of 6/12 or better withprogressive improvement over time. This technique allowsalmost half of patients to achieve an unaided vision of 6/12or better with sutures in situ.

Key words: corneal graft, double-suture, keratoconus.

INTRODUCTION

Penetrating keratoplasty is still the surgical procedure ofchoice for patients with advanced keratoconus who areunable to achieve comfortable, functional visual acuity withcontact lenses.1–9 The success rate of penetrating kerato-plasty for keratoconus has been well described with clearfunctioning graft in 88–95% of eyes at up to 10 years postsurgery.4–6,10–13

Recently newer surgical techniques such as deep lamel-lar keratectomy have been advocated because of poten-tial advantages such as reduced endothelial rejection andtectonic strength.14–16 Direct comparative studies how-ever are relatively sparse, and outcome measures suchas mean Snellen acuity are often similar.16 Closer scru-tiny of comparative studies however indicate thatspectacle-corrected vision is superior in penetratingkeratoplasties.16,17

In previous series of keratoconic patients undergoingsurgery little emphasis has been placed on speed of func-tional unaided or corrected visual recovery. Best correctedvisual acuity (BCVA) that requires a gas permeable contactlens is not the same as best spectacle-corrected visual acuitythat can be achieved earlier in the postoperative recovery. Ifa patient needs to wait up to 2 years to achieve final visualimprovement with spectacles or a contact lens, they can beseverely disabled for activities such as driving. A clearadvantage to the patient will occur if unaided or spectaclevision of 6/12 can be achieved in the early postoperativeperiod.

This study assessed the time period for functional visualrecovery after penetrating keratoplasty in a large cohort ofpatients. It also examined the type of optical correction, ifany that was required, and provides evidence that penetrat-ing keratoplasty by using the Hanna trephine is an effectiveway of treating keratoconus and providing a high qualityvisual outcome.

� Correspondence: Associate Professor Gerard Sutton, the Eye Institute, Level 3/270 Victoria Avenue, Chatswood, NSW 2067, Australia. Email:

[email protected]

Received 17 April 2008; accepted 14 October 2008.

Clinical and Experimental Ophthalmology 2008; 36: 725–730doi: 10.1111/j.1442-9071.2008.01900.x

© 2008 The AuthorsJournal compilation © 2008 Royal Australian and New Zealand College of Ophthalmologists

mailto:[email protected]

METHODS

A retrospective analysis was designed to assess data on 100consecutive patients who were treated for keratoconus withpenetrating keratoplasty utilizing the Hanna trephinebetween 1999 and 2005. All patients were intolerant of gaspermeable contact lenses and had received informed consentabout the risks and benefits of penetrating keratoplasty.All surgeries were performed by a single, experienced,fellowship-trained corneal surgeon (GS).

The Hanna trephine (Moria, Antony, France) was used inall cases, and the surgery was performed in all cases by usingthe same sized donor and host trephine. The donor tissuewas cut from the anterior surface by using the artificialchamber filled with Viscoelastic. All transplants were suturedwith a double running, non-torque 10-0 nylon of 16 bites(Fig. 1).

Patients were routinely reviewed at 1 day, 1 week,1 month, 3 months, 6 months and 1 year – with additionalreviews where necessary. Suture removal was performedbetween 18 months and 3 years depending on visual perfor-mance (in eyes with low astigmatism and good unaidedvision the sutures were left in situ as long as thought clinicallysafe). After surgery all patients were placed on Ciloxan 0.3%(Ciprofloxacin Hydrochloride, Alcon Fort Worth, USA) andMaxidex 0.1% (Dexamethasone, Alcon Fort Worth, USA)four times per day for 1 week before reducing the dosage tothree times per day for a further 3 weeks. FML (Flourometha-lone 1 mg, Allergan, Irvine USA) was then used dailythroughout the initial 12 months or until the sutures wereremoved.

Analyses included: (i) number of eyes/patients achieving6/12 or better without spectacles, (ii) number of eyes/patients achieving 6/12 or better with spectacles, (iii) time toachieve 6/12 visual function with, or (iv) without spectaclecorrection; (v) the number of eyes requiring gas permeablecontact lenses to achieve 6/12 or better visual acuity wasanalysed as a percentage of the total cohort, (vi) refractive

outcome in terms of sphere and cylinder, (vii) keratometricastigmatism, and (viii) allograft rejection rates and graftsurvival.

RESULTS

Table 1 refers to the preoperative demographic variables forthe study.

The trephination was generally centred on the geometriccentre of the cornea unless the cone was significantly inferiorand associated with inferior paracentral thinning, in whichcase the trephination was decentred slightly towards theapex of the cone. Nine patients (11.8%) developed sterilesuture infiltrates, which were managed with increased dex-amethasone to six times a day. One (1.3%) patient requiredan additional interrupted suture for a day one seidel positivewound leak.

Speed of visual recovery

The mean time to achieve a BCVA of 6/12 was9.6 weeks � 8.8 (range 1–40 weeks). These data are high-lighted in Figure 2. Almost two-thirds of the patients wereable to achieve a functional BCVA of 6/12 or better by2 months (63.2%). This increased to 78.9% at 3 months andto 97.9% at 1 year. One hundred per cent of eyes achieved abest spectacle-corrected visual acuity of 6/15 or better at thesame time point (Fig. 2).

Uncorrected and corrected visual acuity

At 1 year 42.4% of patients achieved an unaided visual acuityof 6/12 or better, and 63.6% achieved an unaided visualacuity of 6/18 or better. Figure 3 describes the percentageof eyes that achieve either an unaided or best spectacle-corrected visual acuity of 6/12 or better.

Astigmatism and spherical equivalent

The mean spectacle refractive cylinder was 2.7 D at12 months (n = 67 eyes), and appeared to increase slightlyafter suture removal to 3.13 D (n = 23 eyes) provide statisti-cal analysis.

Topographical cylinder (Orbscan, Bausch & Lomb Roch-ester, USA) based on axial map analysis was 3.4 D at6 months (n = 75) and 3.1 D at 12 months (n = 67), again

Figure 1. Double-suture corneal graft.

Table 1. Preoperative demographics of the patient group

Variable

Age 32.2 � 12.8 years, minimal 12 years,maximal 69 years

Sex 53 men/21 womenFollow up at 6 months 75/76 patients (98.7%)Follow up at 12 months 67/76 patients (88.2%)

726 Sutton et al.


increasing to 3.7 D after all suture removal (n = 23). This wasnot statistically significant at any interval (P = 0.840, 0.276,respectively).

Only eight (10.7%) eyes had a refractive cylinder greaterthan 5.0 D at 6 months. This figure increased to 12.1% at

12 months. In comparison, 16 (21.1%) eyes had a topo-graphical astigmatic value of greater than 5.0 D at 6 monthsand 18.2% at 12 months.

At 6 months the mean spherical equivalent was-1.02 � 2.9 D (n = 75), and at 12 months this increased

43.4%

63.2%

78.9%

96.1% 96.1%97.9%

0.0%

10.0%

20.0%

30.0%

40.0%

50.0%

60.0%

70.0%

80.0%

90.0%

100.0%

2196321

Months taken to achieve BCVA 6/12 or better

Figure 2. Time taken in monthsto achieve best corrected visualacuity (BCVA) 6/12 or betterpostoperatively.

30.3%

66.7%

81.8%

95.5%100.0%

7.6%

15.2%

22.7%

42.4%

56.1%

63.6%

69.7%

80.3% 81.8% 81.8%

89.4%

97.0%100.0%

0.0%

10.0%

20.0%

30.0%

40.0%

50.0%

60.0%

70.0%

80.0%

90.0%

100.0%

6 7.5 9 12 15 18 21 24 30 36 45 60 > 60

Visual acuity (6/_)

12 months postoperative BCVA12 months postoperative UCVA

Figure 3. 95.5% of patients achieve best corrected visual acuity (BCVA) of 6/12 or better after surgery. 42.4% achieve this level without anycorrection. UCVA, uncorrected visual acuity.

Visual recovery after corneal transplants 727


slightly to -1.12 � 3.0 D (n = 66). Again this change wasnot statistically significant (P = 0.873).

Graft rejection and graft survival

Three eyes (3.9%) had undergone one or more episodes ofreversible rejection during the follow-up period, but no eyessuffered corneal graft failure at a mean follow up of 22.1 � 5.1 months (range 12–34 months).

DISCUSSION

The success of penetrating keratoplasty has generally beendefined in terms of visual acuity, astigmatism and graftsurvival. The latter outcome measures reflecting the twomajor problems with the surgery: debilitating astigmatismand rejection.5,11,12,18,19

Many studies have documented the long-term success ofpenetrating keratoplasty for keratoconus.11,18–20 Zadok et al.looked at a group of patients with a mean follow-up of13.3 years and found that 91.7% of patients achieved a visualacuity of 6/12 or better. Sharif and Casey noted that 93% ofgrafts remained clear with a mean follow-up of 6.1 years with81% of eyes achieving 6/12 or better vision.20 Pramanik et al.in 2006 also with a mean follow up of 13.6 years found that73% of patients had achieved visual acuity of 6/12 or betterat last follow up, and that there was an overall graft failurerate of 6.3%.18

Brierly in 2000 reported a series of keratoconic patients,who as a group achieved a visual acuity of 6/12 or better in87% of cases.6 Interestingly however 47% achieved thisvisual acuity with gas permeable contact lenses. Watson, in2004, when comparing visual results in a small group ofpatients who underwent either penetrating keratoplasty ordeep lamellar keratoplasty, found that 95% of patientsundergoing penetrating keratoplasty achieved a BCVA of6/12 or better.16 However, again around 50% of patientsachieved this visual acuity using gas permeable contactlenses.

In a large series of keratoconic patients undergoingkeratoplasty, Lim et al. in 2000 reported excellent results inwhich 86% of eyes achieved BCVA of 6/12 better. Twenty-three per cent of patients in the cohort overall were wearinggas permeable contact lenses.5

These three papers highlight another aspect of visualfunction that is often glossed over: the percentage of eyesthat require gas permeable contact lenses to achieve theirbest vision. Ideally patients would achieve good visionwithout correction or with spectacles. Many patientsprogress to penetrating keratoplasty, at least in part, becauseof the discomfort and inconvenience of the contact lenseswear. In addition a significant percentage of patients haveatopic disease and find the wearing difficult. Anothermeasure of success should therefore be the percentage ofeyes achieving 6/12 with spectacles rather than hard contactlenses.

Probably the best reported visual outcomes have been inthe series reported by Jacobsen and Hojgaard-Olsen. Heused the Hanna trephine to cut donor and host. Onehundred per cent of eyes at last follow up had achieved aBCVA of 6/12 or better.21

Clearly however there is a relatively tight range for visualoutcome measures for penetrating keratoplasty afterkeratoconus. Most series report a BCVA of 6/12 or better ofbetween 85% and 95%. Evidence from the AustralianCorneal Graft Registry, arguably the most statistically reli-able database for these patients, strongly suggests although acentre effect for patients’ outcomes. Those patients under-going procedures with surgeons who perform over 25 pro-cedures a year have better outcomes.10

Secondary measures of success in penetrating kerato-plasty for keratoconus include astigmatism and mean spheri-cal equivalent. Javadi et al. in 2005 reported 164 eyes that hadundergone penetrating keratoplasty for keratoconus. Themean spherical error was -0.61 � 2.6 D, and the astigma-tism was 3.4 � 1.8 D. They found no correlation in theresults with trephination or suturing technique supportingthe findings in the summary paper of Frost et al.4,12

Olsen in the same year reported a mean astigmatism of2.76 D with only 15% of eyes having astigmatism of greaterthan 5 D. He reported that 77% of eyes achieved a BCVA of6/7.5 or better.13

Astigmatism as a measure of success also appears to berelatively constant with a mean of between 2.75 and4 D.4,5,12,13,21–24

This series of patients undergoing penetrating kerato-plasty for keratoconus with the Hanna trephine providesnovel information about visual recovery for both patientsand surgeons. It indicates that the vast majority of patientshave stable refractions and can be fitted with spectacles at3 months, and over two-thirds can expect to achieve a func-tional visual acuity of 6/12. In most series published thecorrected visual acuity measures include both rigid gaspermeable contact lenses and spectacles.4,5,16 In thosestudies that do report the percentage of eyes that wear gaspermeable contact lenses, the incidence ranges from 16% to50%.5,16,25

Another measure of success of penetrating keratoplastyshould be the speed at which patients can achieve functionalvision, indeed, this is the most common question asked byprospective patients. When sutures are still in situ, during thefirst 12–18 months, the fitting of a gas permeable contactlens is associated with risks to the suture, and in most casesthe use is left until the suture has been removed. If suturesremain in situ indefinitely, the risk of microbial keratitisincreases.26–28 This means that patients that can only achievetheir best visual acuity with a gas permeable contact lens mayhave to wait a considerable period of time before realizingthe benefit of their surgery. Typically the need to wear a gaspermeable contact lens is a reflection of astigmatism, irregu-lar astigmatism or anisometropia.29 Ideally patients shouldachieve unaided, or at least spectacle-corrected visual acuity,relatively early in the postoperative period. Deep anterior

728 Sutton et al.


lamellar keratoplasty (DALK) has gained in popularity as analternative to penetrating keratoplasty for the surgical man-agement of keratoconus. There are certainly theoreticaladvantages that proponents of DALK have argued makeDALK the preferred option. Speed of visual recoveryafter DALK is often quoted as a reason to choose thisprocedure.16,17 There are no studies to support this assertion.Our results suggest that visual recovery after penetratingkeratoplasty is in fact relatively quick.

In this series, 43.5% of patients eventually achieved anunaided visual acuity of 6/12 or better. This reflects a rela-tively low astigmatic outcome, but more importantly anextremely low mean spherical equivalent and, to the authors’knowledge, is the highest figure reported in the peer-reviewed literature. We could find no other study in whichuncorrected visual acuity was recorded after penetratingkeratoplasty.

The overall astigmatic results in this series are at the lowerend of the published data4,5,12,13,21 and importantly, only12.1 % had refractive cylinder greater than 5 D by 1 year.Whereas, de Toledo et al. reporting on 201 cases of penetrat-ing keratoplasty for keratoconus reported a mean cylindricalerror of greater than 5 D (5.56 D).19

This series represents the largest published series utilizingthe Hanna trephine system and a double running, non-torque suture. Jacobsen and Hojgaard-Olsen published asmaller series of 57 eyes undergoing penetrating kerato-plasty, but these included patients with Fuchs’ dystrophy andother corneal disorders likely to produce lower postoperativeastigmatism and ametropia.21 However, the spherical equiva-lent and refractive astigmatism was similar to this reportedseries. It must be pointed out however that in a recent meta-analysis study, Frost et al. reported no evidence of any advan-tage of one suture technique over another.4

Allograft rejection in penetrating keratoplasty may be ashigh as 20% in large series.19 Interestingly, the mean rate ofallograft rejection in this series was at the lower end of thepublished spectrum and may reflect the protocol of using onedrop of topical corticosteroids per day throughout the firstyear. Lim et al. had a similarly low percentage of eyes under-going rejection episodes (3%), although one eye in the serieshad a graft failure.

CONCLUSION

The focus of this study is visual function and the speed ofvisual recovery. Penetrating keratoplasty for keratoconus byusing the Hanna trephine system is capable of providing notonly good visual outcomes but rapid visual recovery. It isinsufficient to assess surgical outcomes based purely on finalSnellen acuity without describing the method in which suchfinal acuity is achieved. Functional unaided visual acuity canbe achieved in a high percentage of patients, and over two-thirds can expect to achieve this level of vision with glassesby 3 months. Further this level of vision can be achievedprior to suture removal and without the need for gas perme-able contact lenses in the vast majority of patients. When

surgical techniques such as DALK are assessed in comparisonwith penetrating keratoplasty, speed of recovery, visualacuity with spectacles and unaided visual acuity must also beassessed.

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rapid visual recovery after penetrating keratoplasty for keratoconus

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