Penetrating Keratoplasty in South East London 1981–1986: Epidemiological Aspects and Demands on Medical Resources

We have compared penetrating keratoplasty at a teaching hospital and a district general hospital (DGH). At the teaching hospital, the pathology was similar to previous reports, but at the DGH the patients were older (P less than 0.01) and had a worse prognosis. The vision in the unoperated eye was also frequently poor. The number of postoperative outpatient visits within a hospital was unrelated to the original disease, and there was no statistically significant difference between the two centres. At the DGH, a corneal transplant patient requires the outpatient resources equivalent to three matched cataract patients. The implications for medical manpower requirements are discussed.

Surgical management of coexisting pseudophakic bullous keratopathy and glaucoma

This technique is a 1-step surgical management approach for patients with pseudophakic bullous keratopathy, glaucoma, and an unsatisfactory intraocular lens (IOL). The outcome of 4 consecutive patients who had penetrating keratoplasty, IOL removal, vitrectomy, transscleral sutured IOL implantation, and trabeculectomy by the same surgeon were reviewed. All patients had had intracapsular cataract extraction with anterior chamber IOL implantation and were on antiglaucoma therapy. Main outcome measures were Snellen visual acuity and intraocular pressure. A 1-stage quintuple procedure can achieve relatively rapid visual rehabilitation in these high-risk eyes. The role of filtration surgery is controversial, but it was partially successful in controlling postoperative intraocular pressure.

Topical anesthesia: Proxymetacaine versus Amethocaine for clear corneal phacoemulsification

PURPOSE

To evaluate the use of proparacaine (Proxymetacaine) versus tetracaine (Amethocaine) as the topical anesthetic agent for phacoemulsification cataract surgery using a 3.5 mm clear corneal sutureless incision.

SETTING

Harold Wood Hospital, Romford, Essex, United Kingdom.

METHODS

This prospective study comprised 40 randomly selected patients. Twenty were given Proxymetacaine and 20, Amethocaine. The level of discomfort experienced during delivery of the topical anesthetic agent and during and immediately after surgery was measured using a pain score. During surgery, topical anesthesia was supplemented by intracameral lignocaine 1%.

RESULTS

Patients given Proxymetacaine experienced no stinging sensation during its administration; those given Amethocaine reported varying degrees of discomfort. The difference between groups was statistically significant (P < .01). There was no difference between groups in the amount of discomfort experienced intraoperatively or postoperatively.

CONCLUSION

Proxymetacaine is the topical analgesic of choice for phacoemulsification because it produced no discomfort on administration yet had the same analgesic properties as Amethocaine.

Why are new patients coming to the eye clinic? An analysis of the relative frequencies of ophthalmic disease amongst new patients attending hospital eye clinics in two separate locations

We have analysed 64,417 patient-attendances by 56,409 patients to a dedicated ophthalmic new patient service to assess the demographic and epidemiological parameters of this population. Forty-three point five per cent were male and 56.5% female. Nine per cent of patients were under 16 years of age while 27.5% were over 70 years. Comparison of patients attending an outreach new patient clinic with that at the main hospital showed that a higher proportion of patients under 16 years were seen at the outreach clinic (p < 0.001), whereas the main clinic saw a higher proportion of patients in the 16-69 year age group (p < 0.001).

Topical anaesthesia for cataract surgery

First, do no harm. We believe that the analgesia provided by topical anaesthetic is adequate for small-incision cataract surgery and does not compromise the safety of the surgery. In addition, the lack of amaurosis is ideal for day-case surgery, which itself is increasingly popular. If preventable, why not prevented? The greatest attraction of topical anaesthesia is its complete absence of the complications described for injectional local anaesthetic techniques. We therefore recommend that our colleagues consider topical anaesthetic for patients undergoing small-incision cataract surgery under local anaesthesia. Our policy for the past 3 years has been to use only topical or general anaesthetics for cataract surgery.

Misdiagnosis of acute angle closure glaucoma

When acute glaucoma presents in its classical form, the diagnosis is fairly simple to make. However, atypical presentations are not uncommon and the diagnosis can be missed. This inevitably leads to a delay in treatment which can permanently compromise visual function. We have studied which doctors are most likely to make a misdiagnosis and calculated the resulting delay in treatment. All patients with acute glaucoma attending Whipps Cross eye unit between 1991 and 1994 were identified and their notes obtained. Thirty-eight patients were found to have a had diagnosis of acute closed angle glaucoma. In only 39.5% was the diagnosis correctly made by the referring practitioner and a misdiagnosis resulted in a mean delay of treatment of 5.8 days. General practitioners were the most likely group to have difficulty making the diagnosis, while casualty officers were most likely to make the correct diagnosis. Because acute glaucoma can present without its typical features, there needs to be a high index of suspicion for this diagnosis. This diagnosis does not require expensive equipment or a high level of training--all our patients had a significant reduction in vision. Any patient who has a red eye and a subjective reduction in vision should be referred to an ophthalmologist the same day.

The spectrum of herpes simplex virus disease of the anterior segment in the 1990s

We have sampled our clinic population in order to ascertain the proportion with herpetic eye disease of the anterior segment. The age, gender predominance, and incidence of bilateral disease amongst such patients has not changed over the past 20 years. The predominant disease type was stromal keratitis, with significant morbidity and visual handicap. Herpetic eye disease of the anterior segment utilizes only 1% of out-patient clinic resources overall, but 17% of specialist external disease clinic time. There was a statistically significant correlation between total length of follow-up and reduced visual acuity. It would seem that the prevalence of herpetic eye disease of the anterior segment appears to have halved since comparable reports were published. In addition, the prognosis of the disease, in terms of the prevalence of visual impairment, has worsened.

Resource management of cataract patients: effect of four contemporary incisions on postoperative visits required

PURPOSE

To assess the effect of four contemporary cataract surgery incisions on the number of postoperative visits required.

SETTING

Cataract service of a large free-standing eye hospital in a capital city.

METHODS

This study comprised a prospective evaluation of three incisions for phacoemulsification and a retrospective assessment of age- and sex-matched patients having conventional corneal section extracapsular cataract extraction. All patients had age-related cataract. Main outcome measures were complications, best corrected and uncorrected visual acuities 6 weeks after surgery, and number of visits before discharge. Follow-up was at least 6 months.

RESULTS

Patients who had small and scleral incisions had better uncorrected visual acuities 6 weeks postoperatively because they had less astigmatism. Patients who had small and scleral incisions required significantly fewer postoperative visits before discharge.

CONCLUSION

A prospective assessment of the feasibility and acceptability of reduced postoperative follow-up after phacoemulsification using a scleral tunnel is required.

Resource management of cataract patients: can visual rehabilitation be achieved in three visits?

PURPOSE

To assess the feasibility and acceptability of reduced postoperative follow-up after phacoemulsification using a scleral tunnel technique.

SETTING

Cataract service of a large free-standing eye hospital in a capital city.

METHODS

In this pilot study, patients with age-related cataract requiring surgery were prospectively recruited to a standardized management protocol, the three-episode model, with assessment by an independent observer. Main outcome measures were number of postoperative visits, patient satisfaction, and refractive error at 2 and 6 weeks postoperatively.

RESULTS

Almost 90% of patients could be managed within this model of care. Patient satisfaction was high; no patient requested further hospital visits. Mean change in refractive error between 2 and 6 weeks was 0.34 diopters (D), with a modal value of 0 D. Patients were able to obtain spectacles 2 weeks postoperatively because little change in refraction occurs over the next month.

CONCLUSION

The three-episode model for the management of patients with cataract could result in significant financial savings. Such savings could be used to treat patients with cataract who otherwise would not have treatment or would have their surgery delayed.

The visual prognosis following HLA-matched keratoplasty for high-risk patients

We report the clinical details of 30 HLA-matched corneal grafts with a mean follow-up of 29 months. Few of the patients were immunologically naive as almost all had received previous unmatched grafts. The two-year survival rate was 77%, comparable with other series. A majority of patients obtained good vision, and this was statistically superior to a recent large series. Almost all remained on their topical medication indefinitely. The contralateral visual acuity was surprisingly good, but there are few published data for comparison. We were unable to document an enhanced prognosis with a higher degree of HLA-A, B or DR match, possibly because of the small numbers.

Visual prognosis following accidental vitreous loss during cataract surgery

Over the past 7 years there has been a change in the management of accidental vitreous loss during cataract surgery. There has been a reduction in immediate postoperative complications such as hyphaema. No immediate post-operative complications were observed during the last 18 months of the study. Whereas previously many of these patients remained aphakic, there was a change initially to anterior chamber intraocular lenses (IOLs) and now the vast majority receive capsule-supported sulcus-fixated posterior chamber IOLs. All patients had improved vision post-operatively by a mean of 4 Snellen lines, although they did not achieve the acuities of age- and sex-matched controls (p = 0.015).

Refractive results after corneal triple procedures (PK+ECCE+IOL)

We have analysed the refractive results of corneal triple procedures (penetrating keratoplasty with extracapsular cataract extraction and posterior chamber intraocular lens implantation) in 52 eyes of 47 patients with a mean follow-up of 39 months. The patients were predominantly old and female and most received unilateral surgery. The contralateral acuity was 6/24 or worse in more than 50% of cases at the time of surgery. Many of these patients were significantly ametropic pre-operatively. Biometry does not seem to have improved the refractive results in those patients in whom it was attempted. The majority of patients were hypermetropic when their refraction stabilised, with resulting poor uncorrected visual performance. Possible improvements are discussed.

Medical manpower requirements following penetrating keratoplasty for herpes simplex keratitis

We have compared the post-operative course of patients requiring penetrating keratoplasty for herpes simplex virus keratitis, keratoconus, and Fuchs' endothelial dystrophy with a minimum of two years follow-up. Although some expected differences (age, sex) were found between these three groups, the number of post-operative clinic visits was not different between the three groups. This is contrary to the common belief that patients requiring penetrating keratoplasty for herpes simplex keratitis are high risk, and will make greater demands on medical resources in the post-operative period. The management of our patients with herpes simplex keratitis is not statistically different from a similar group managed at another centre.

Preliminary Data Suggest a Role for Bacterial Superinfection of a Viral Keratitis after Zosteriform Spread of Herpes Simplex virus to the Eye of the Mouse

After inoculation of herpes simplex virus (HSV) on the snout of the mouse, spread to the eye occurs via neural pathways. The keratitis which ensued was clinically atypical for a pure herpetic keratitis, leading to a search for other causative agents. Preliminary data suggests that bacteriological superinfection of the viral keratitis occurs frequently, producing a unique experimental model.

Neural spread of herpes simplex virus to the eye of the mouse: microbiological aspects and effect on the blink reflex

This paper reports the microbiological aspects of zosteriform spread of herpes simplex virus (HSV) to the eye in the NIH strain of inbred mouse. Microbiological data support the concept of true zosteriform spread of herpes simplex virus from the inoculation site on the snout to the trigeminal ganglion, and thence to the eye. Following zosteriform spread of HSV to the eye, there is a frequent bacterial superinfection and this is associated with a typical clinical picture. Treatment of the mice with intensive systemic and topical antibiotics is able to alter the frequency with which this type of keratitis is seen.

Epithelial cyst in the anterior chamber after penetrating keratoplasty: a rare complication

We report the case of a 25-year-old man who had a penetrating keratoplasty for keratoconus. A year and a half after surgery a cyst was noted in the anterior chamber, which was observed to enlarge over six months. Because of anxiety about endothelial touch, it was removed surgically. Histologically the cyst was composed of stratified, non-keratinized squamous epithelium attached to loose fibrovascular tissue including islands of melanin-containing epithelial cells. This was interpreted as an epithelial implantation cyst of the anterior chamber of corneal origin attached to iris tissue.

Experimental contamination of Minims of fluorescein by Pseudomonas aeruginosa

Contamination of fluorescein solutions by Pseudomonas aeruginosa has been a concern of ophthalmologists for many years because of the severity of pseudomonas keratitis. Attempts to prevent contamination have been directed at stringent sterility control during manufacture and the introduction of single-dose disposable containers such as Minims. Deliberate contamination of Minims fluorescein with Pseudomonas aeruginosa was attempted. Under conditions likely to be met with in clinical practice the contents remained sterile. However, under extreme conditions of immersion in pure broth culture of Pseudomonas aeruginosa contamination could be achieved. The relevance of these results to clinical practice is discussed.

Informing the hospital of patients' drug regimens

Patients who are admitted to Southampton Eye Hospital are asked to bring a form from their general practitioner with details of all drugs that have been prescribed and to bring all their current medications. We carried out a study to find out what proportion of patients were taking medicines by prescription only and how many of these were known to the general practitioner. Less than half of the forms completed by the general practitioners were correct.